Indian Patents. 256675:ACRYLIC ANTIMICROBIAL FIBER AND A METHOD OF MAKING THEREOF

Title of Invention	ACRYLIC ANTIMICROBIAL FIBER AND A METHOD OF MAKING THEREOF
Abstract	An acrylic fiber having antimicrobial activity and a method of making thereof is disclosed. Micro-reservoirs are formed in the fibers in which the antimicrobial constituents are embedded.

Full Text	FORM - 2 THE PATENTS ACT, 1970 (39 OF 1970) AND THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10; rule 13) ACRYLIC ANTIMICROBIAL FIBER AND A METHOD OF MAKING THEREOF ADITYA BIRLA SCIENCE & TECHNOLOGY CO. LTD. an Indian Company of Aditya Birla Center, 2nd floor, C Wing, S. K. Ahire Marg, Mumbai 400 025, Maharashtra, India THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED. Field of the invention The present invention relates to textile fibers. Background of the invention The term "fiber" or "textile fiber" means a substance which is capable of being spun into a yarn or made into a fabric by bonding or by interlacing in a variety of methods including weaving, knitting, braiding, felting, twisting, or webbing, and which is the basic structural element of textile products. Fibers are classified on the basis of their length such as short fibers or staple fiber and long fibers or filament fiber. The fibers can also be classified on the basis of their origin such as natural fibers and man-made fibers. The term natural fibers means any fiber that exists as such in the natural state e.g. vegetable fibers or wood fibers. The other type of fibers is obtained from chemical substances. These are called man made fibers. They are rayon, polyester, nylon, acrylic (cashmilon) etc. For centuries, mankind has relied upon various plants and animals to provide raw materials for fabrics and clothing. In recent times, the industrialization and scientific advancement has provided several improved materials having far superior properties, particularly suitable for clothing. Acrylic fibers are synthetic fibers containing at least 85% of acrylonitrile monomer. The acrylic fibers are prepared from a polymer Polyacrylonitrile which is obtained by free radical polymerisation with an average molecular weight of -100,000. Typical properties of acrylic fibers include, resistance to moths, oils, and chemicals. Furthermore, they are also resistant to deterioration from sunlight exposure. The process steps involved in the preparation of Acrylic fibers are as follows: 2 The acrylic polymer is dissolved in solvents like N,N-dimethylformamide or aqueous sodium thiocyanate. Then it is metered through a multi-hole spinnerette and the resultant filaments are coagulated in an aqueous solution of the same solvent. The resultant filaments are washed, stretched, dried and crimped to obtain final acrylic fibers. Acrylic fibers are typically produced in a range of deniers from 1 to 15. Acrylic is lightweight, soft, and warm, with a wool-like feel. It dyes very well and has excellent colorfastness. It is resilient, retains its shape, and resists shrinkage and wrinkles. Acrylic fibers are commonly used in sweaters, hand-knitting yarns, rugs, awnings, boat covers, and beanies; the fiber is also used as a precursor for carbon fiber. From the spun or filament yarn, fabric is formed by knitting or weaving operations. Knitted fabrics can be made by using hooked needles to interlock one or more sets of yarns through a set of loops. The loops may be either loosely or closely constructed, depending on the purpose of the fabric. Knitted fabrics can be used for hosiery, underwear, sweaters, slacks, suits, coats, rugs and other home furnishings. Knitting is performed using either weft or warp processes. Some typical preparations that are involved in the weaving operations are warping, slashing or sizing. Sizing agents are added to the yarn by solution or pad/dry techniques. Differences in raw materials, processing chemicals, fiber diameter, post treatments and blend ratios can be manipulated, to produce a fiber having customized properties suitable for desired application. It is often desired that the acrylic fabrics possess typical properties such as thermal stability, ability to retain perfumes, antibacterial properties and the like. These properties are essential in several industrial as well as household applications. There has been a considerable interest in developing such materials. In order to impart various desirable properties to the fabric as mentioned above to the fabric, several constituents with various properties are added. Such constituents include antimicrobial agents, deodorizing agents, antistatic agents, perfumes. Besides such specific constituents, generic constituents for improving overall quality of the fabric, such as sizing agents, antimicrobial constituents for increasing yarn softness and pliability are also added. Prior Art US patent 5405644 discloses a process of manufacturing an antimicrobial fiber which involves mixing of silver-containing inorganic microbicide composition with fiber material which is further dipped in discoloration inhibitor containing solution. The process as disclosed in US 6368361 involves contacting and immersing the fiber in an aqueous solution containing a cationic surfactant with a quaternary ammonium salt group, a water-soluble protein, and an alkaline compound are dissolved. The fiber is then separated from the aqueous solution and immersed in another aqueous solution containing tea polyphenol which is an antimicrobial agent. A composite textile fabric involving a blend of two fabric layers wherein one of the fabric layers is coated with an antimicrobial agent such as silver and copper sulfide is disclosed in US Patent 6194332. 20040247653 discloses a process of preparing an antimicrobial and antiviral polymeric material which involves embedding microscopic water insoluble powder particles of ionic copper oxide into the polymer material. US 4649078 discloses a lower temperature technique for incorporating antimicrobial agents into the fibers which involves passing the fiber into a liquid containing an antimicrobial agent such as bis(tri-n-butyl tin)oxide, n-trichloromethylthio phthalimide, n-(2-methylnaphthyl)maleimide, 2,4-dichlorobenzyl alcohol and 2-(n-octyl-4-isothiazolin-3-one. US 3959556 discloses method of preparation of improved composite antimicrobial yarns which involves extruding a spinnable solution of a synthetic thermoplastic resin and an antimicrobial agent. The antimicrobials are selected from a group consisting of 2,4,4'-trichloro-2'-hydroxydiphenyl ether; 2,2'-methylenebis- (3,4,6-trichlorophenol); and 2,2'-thiobis (4,6-dichlorophenol). US 6436419 discloses a method for preparing antimicrobial polymer which involves coating of a polymer with an acid dye attached with an quaternary ammonium salt (antimicrobial agent). Earlier known processes of incorporating such antimicrobial constituents, as reported in the above mentioned patents/applications, mainly involved conventional methods like spraying, encapsulating, solvent spinning the antimicrobial constituents on the fabric. However, these methods suffer from several disadvantages which include non-uniform and improper adhesion of antimicrobial constituents onto the fiber material and gradual washing out of the antimicrobial constituents over a period of time and which affects the feel and texture of the fabric. There is thus felt a need for a process of incorporating antimicrobial constituents into fabric which overcomes these shortcomings. Objects of the Invention It is an object of this invention to provide antimicrobial acrylic fibers, wherein at least one antimicrobial constituent is incorporated in the body of the fiber. Another object of this invention is to provide a process of incorporating antimicrobial constituents into acrylic fibers which ensures uniform distribution of the antimicrobial constituent throughout the fiber length. Yet another object of this invention is to provide antimicrobial acrylic fibers wherein the antimicrobial constituents are retained in the acrylic product over a prolonged period of time. Yet another object of this invention is to provide a process of incorporating antimicrobial constituents to acrylic fibers which does not affect the feel and texture of the fabric. Still another object of this invention is to provide a process of incorporating antimicrobial constituents to acrylic fibers such that inherent properties of the acrylic fibers such as fiber strength, linear density, tenacity, heat resistance, dyeability and drying properties are not altered. 6 Definitions: As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise. "Non-aqueous phase" means a melted mixture in liquid state which is water insoluble. "Aqueous phase" means substance dissolved in water. "Acrylic Polymer dope" means regular acrylic and modacrylic polymers, containing atleast 35% acrylonitrile as a monomer for modacrylic and 85%) for regular acrylic polymer. The other comonomers can be methylacrylate, ethyl vinyl ether, vinyl bromide, vinyl chloride, vinyledene chloride, vinyl acetate, vinyl sulfonic acid, itaconic acid, and/or methylmethacrylate and sulfonated monomers such as sodium styrene sulfonate, sodium methallyl sulfonate, sodium sulfophenyl methallyl ether. "Preform mass" means an intermediate material suitable for making fibers. Summary of the Invention In accordance with this invention there is provided an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising: • at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation, 7 • at least one water insoluble antimicrobial constituent soluble in said solvent, said constituent being in the range of about 0.001 to 3.5% of the mass of the formulation, • at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40,said surfactant being in the range of 0.001 to 3% of the mass of the formulation, • acrylic polymer in the range of about 1% to 15% of the mass of the formulation, • water in the range of about 50% to 90 % of the mass of the formulation. Typically, the antimicrobial constituent is at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester), o-(2-naphthyl) methyl (3-methylphenyl) thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenoI,4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT] 2-n-octyl-4-isothiazolin-3-one, 1-phenoxy propan-2-ol, pentachlorophenol, 5-chloro-2-dichlorophenoxy phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol. Typically, the solvent is at least one solvent selected from a group of solvents consisting of C10-C44 alkanes (paraffmic hydrocarbons), polyethylene, polypropylene, polypropylene glycol, polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, polyesters, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils ,mineral oil paraffins and diethylphthalate. Typically, the surfactant is at least one non-ionic or anionic surfactant selected from a group of non-ionic or anionic surfactants consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol Typically, the phenoxy like ethoxylated non-ionic or anionic surfactant is at least one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether, Nonylphenol polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether, Polyoxyethylene(l0) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether, Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether, Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene(l00) nonylphenyl ether, Polyoxyethylene( 150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2- ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) ,Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol 15-mole ethoxylate), Surfonic N-200 (nonylphenol 20-mole ethoxylate) , Surfonic N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17 (ethoxylated and propoxylated linear primary 12-14 carbon number alcohol), Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic DNP-40 , fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters. In accordance with one preferred embodiment of the invention, the HLB value of the surfactant is between 16 and 40. In accordance with one aspect of the invention, the antimicrobial constituent, the solvent and the surfactant are processed to form micro-reservoirs which are embedded into the body of the formulation. Typically, the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm. The invention also extends to an antimicrobial acrylic fiber, yarn and fabric manufactured from a formulation in accordance with this invention. In accordance with this invention there is also provided a process for preparation of an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps : • admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent followed by heating the resulting admixture upto 95°C to obtain a non-aqueous phase; • dissolving and stirring a surfactant, optionally with a co-surfactant, in water to obtain an aqueous phase; • admixing and homogenizing the non-aqueous phase with the aqueous phase to obtain a micro-emulsion; dispersing the micro-emulsion throughout the mass of the acrylic polymer dope to obtain a preform mass wherein the antimicrobial constituent is in the form of evenly dispersed micro-reservoirs. Typically, the pH of the aqueous phase is in the range of 7 to 13. Typically, the amount of non-aqueous phase in the micro-emulsion is in the range of 0.1 to 40% of the mass of the micro-emulsion. Typically, the amount of surfactant in the micro-emulsion is in the range of 0.1 to 20% of the mass of the micro-emulsion. Typically, the proportion of antimicrobial constituent in the acrylic product is in the range of 0.001 to 5% with respect to the mass of the acrylic product. Typically, the solvent for polyacrylonitrile is at least one selected from a group consisting of sodium thiocyanate , dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, ethylene carbonate, aqueous zinc chloride and aqueous nitric acid. The polymer percentages in the acrylic dope will vary depending on the solvent For dimethyl formamide, acrylic polymer concentration soluble in polymer dope is as high as 28-32%; for dimethyl acetamide, it is as high as 22-27%; for dimethyl sulfoxide, it is as high as 20-25%; for ethylene carbonate, it is as high as 15-18%, for aqueous nitric acid, it is as high as 8-12% and for zinc chloride, it is as high as 8-12%. For Sodium thiocyanate as a solvent, acrylic polymer concentration is as high as 10-15%. Brief Description of the accompanying Drawings: The invention will be described in detail with reference to the accompanying drawings. In the accompanying drawing, Figure 1 illustrates the block diagram showing the method steps involved in the process in accordance with this invention. Figure 2 illustrates the cross-sectional view of antimicrobial acrylic fibers prepared in accordance with this invention which shows uniform distribution of micro-reservoirs of antimicrobial constituents entrapped across the length of the fibers. Detailed Description: Acrylic fibers were the first viable manufactured fibers. The reason behind the most widespread use of these fibers lies in their versatility. Furthermore, these fibers also have peculiar ability to blend easily with many fibers which makes them the fibers of choice. Though fibers and fabrics made from them have many desirable properties, oftentimes, consumers expect performance characteristics beyond those for which fibers were designed. In order to meet with these increasing expectations, various antimicrobial constituents are incorporated in the acrylic fibers. There has been a considerable interest in developing such materials. One of the additional desirable properties of acrylic fibers which has enormous demand is "antimicrobial activity". In accordance with this invention there is provided an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising: • at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation, • at least one water insoluble antimicrobial constituent soluble in said solvent, said constituent being in the range of about 0.001 to 3.5% of the mass of the formulation, • at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40,said surfactant being in the range of 0.001 to 3% of the mass of the formulation, • acrylic polymer in the range of about 1% to 15% of the mass of the formulation, • water in the range of about 50% to 90 % of the mass of the formulation. In accordance with the invention, anti-microbial constituent is typically at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester), o- (2-naphthyl) methyl (3-methylphenyl) thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenol, 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT], 2-n-octyl-4-isothiazolin-3-one, 1-phenoxy propan-2-oI, pentachlorophenol, 5-chloro-2-dichlorophenoxy phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol. The antimicrobial constituent impart antimicrobial property to the fibers and ultimately to the fabric or garments made from these fibers. In accordance with this invention , only non-aqueous solvent is used which is typically selected from a group of solvents consisting of C10-C44 alkanes (paraffinic hydrocarbons), polyethylene, polypropylene, polypropylene glycol, 13 polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils, mineral oil paraffins and diethylphthalate. Preferably, paraffin wax either alone or in combination with stearyl alcohol is used as the non-aqueous solvent. In accordance with this invention only water soluble non-ionic or anionic surfactant/co-surfactant is used. Typically, the non-ionic or anionic surfactant is selected from a group consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol. Typically, the alkyl phenoxy ethoxylated non-ionic or anionic surfactant is at least one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether, Nonylphenol polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether, Polyoxyethylene(l0) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether, Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether, Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene(l00) nonylphenyl ether, Polyoxyethylene(150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol 15-mole ethoxylate), Surfonic N-200 (nonylphenol 20-mole ethoxylate) , Surfonic N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17 (ethoxylated and propoxylated linear primary 12-14 carbon number alcohol), Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic DNP-40, fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters. The non-ionic or anionic surfactant is selected such that the lipophilic portion of the non-ionic or anionic surfactant is compatible with the antimicrobial constituent and the surfactant forms oil in water microemulsion. Surfactants with HLB values within the range of 9 to 40 are used. Preferably, non-ionic or anionic surfactants with HLB values more than 13 are used. In accordance with one preferred embodiment of the invention, the HLB value of the surfactant is between 16 and 40. In accordance with one aspect of the invention, the antimicrobial constituent, the solvent and the surfactant are processed to form micro-reservoirs which are embedded into the body of the formulation. The antimicrobial acrylic contains uniformly dispersed micro-reservoirs throughout the body of the fibers. The micro-reservoirs are discrete, nano-sized structures without any definite geometrical shape. Typically, the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm. The invention also extends to an antimicrobial acrylic fiber, yarn and fabric manufactured from a formulation in accordance with this invention. In accordance with this invention there is also provided a process for preparation of an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps : • admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent followed by heating the resulting admixture upto 95°C to obtain non-aqueous phase ; • dissolving and stirring a surfactant, optionally with a co-surfactant, in water to obtain an aqueous phase; • admixing and homogenizing the non-aqueous phase with the aqueous phase to obtain a micro-emulsion; • dispersing the micro-emulsion throughout the mass of the acrylic polymer dope to obtain a preform mass wherein the antimicrobial constituent is in the form of evenly dispersed micro-reservoirs. Typically, the pH of the aqueous phase is in the range of 7 to 13. Typically, the amount of non-aqueous phase in the micro-emulsion is in the range of 0.1 to 40% of the mass of the micro-emulsion. Typically, the amount of surfactant in the micro-emulsion is in the range of 0.1 to 20% of the mass of the micro-emulsion. Typically, the proportion of antimicrobial constituent in the acrylic product is in the range of 0.001 to 5% with respect to the mass of the acrylic product. Before arriving at the optimum concentration of the surfactant to be used, cloud point of the aqueous phase is determined. Furthermore, alkalinity of the aqueous phase matches with that of the acrylic polymer dope thereby avoiding any drastic change in the alkalinity during the emulsification and homogenization step. Typically, the melted non-aqueous phase containing antimicrobial constituent in a non-aqueous solvent along with aqueous phase containing surfactants is emulsified using high speed mixers such as Ultraturrex or a mechanical emulsifier; a colloid mill; a high pressure homogenizer and an ultrasonic emulsifier to form a microemulsion. The micro-emulsion may contain further additional antimicrobial constituents, if desired. It is important that the non-aqueous phase is maintained in liquid state throughout the mixing process. The aqueous phase therefore is typically heated upto a particular temperature to ensure that the temperature of the resulting emulsion is above the melting point of the non-aqueous solvent. If this does not happen, the resulting emulsion will break down. The active ingredients are released from the micro-reservoir into the acrylic matrix. The structure of micro-reservoir, acrylic and surrounding conditions determine the release rate of the antimicrobial constituent. The molecules of the volatile antimicrobial constituents migrate from micro-reservoirs to the surrounding primarily by diffusion. The antimicrobial constituent is released from the matrix in a controlled release manner. Preform mass is spun to fiber in a bath containing 12.5% of Sodium thiocyanate solution. The temperature of the bath is maintained at -2.5°C. Thereafter, the fiber is cold stretched, gel treated at pH 2.8 at 45°C, then hot stretch at 90°C. The void in the fibers is removed by treating the fiber at 125°C. Fiber is then relaxed and annealed at 120 C and then taken up for post-treatment. The acrylic fibers can be further subjected to post treatment to make fabric which typically involves: o Convert to Yarn in blend or pure o Convert to Warp Beam o Sizing o Fabric Manufacturing- Weaving /Knitting o Dyeing o Finishing Alternatively, the filaments so obtained are further blended using standard equipment. The blended fibers are laid in to a web using standard equipment followed by Consolidation of the web to obtain Non-woven Acrylic Fabric. The acrylic product made from the formulation in accordance with this invention contains uniformly dispersed micro-reservoirs throughout the mass which is shown in Fig. 2. The antimicrobial constituent enriched acrylic fabrics as prepared in the above examples can be tested for antimicrobial activity by various test procedures which include antimicrobial assays used to determine or confirm the effectiveness of treatments applied to medical devices, medical and commercial textiles, and other products. Test methods for measuring the antimicrobial activity include ASTM, AATCC, and other modified methods. Testing includes antibacterial and antifungal activity, with both qualitative and quantitative assays available. AATCC 100 is a qualitative test for antibacterial activity. Test acrylic fiber/fabric specimens are placed into contact with a nutrient agar which has been streaked with a microbe such as Staphylococcus aureus, Escherichia coli bacterial culture. Samples are inoculated with Staphylococcus and evaluated for percent reduction of the bacteria over selected contact periods of 1 -24 hours. Turnaround Time is usually 5 days. The specimens are then incubated at a temperature 37 °C for a period of time of 24 hours. After the 24 hour incubation period, the samples are visually checked for the growth of bacteria. The AATCC 174, Part III protocol provides a qualitative test for antifungal activity. Acrylic fiber/ fabric specimens are subjected to the growth of a common fungus, Aspergillus niger, on Sabouraud Dextrose agar. Prewet specimens are inoculated and incubated at 28 °C for seven days. Specimens are then assessed for growth of the fungus. ASTM E2180-01 test method is used for testing inhibitory mold activity of the acrylic product (fiber /fabric) prepared in accordance with this invention. The antimicrobial acrylic fibers contain the entrapped antimicrobial constituent in releasable form. Microscopic examination of the micro-reservoirs in the acrylic fibers is shown in Fig 2. The resultant acrylic fabric containing antimicrobial constituent are tested. Linear Density (Denier) of the acrylic Fibers is determined by using standard ASTM Test Method (D 1577). The denier of the standard acrylic fiber (acrylic fiber without any antimicrobial constituents) and anti-microbial enriched acrylic fiber remains the same. Thus addition of antimicrobial constituents does not change the linear density of the acrylic fibers. Tensile strength and Young's modulus of acrylic fiber sample is tested on an Instron tensile testing machine as per the ASTM CI557-03 procedure at ambient temperature. Visual appearance of the antimicrobial enriched fiber is evaluated by methods as prescribed in AATCC 124. As far as parameters like % Loss in Dry Tenacity and % loss in dry elongation are concerned, these remain the same in the antimicrobial enriched acrylic fiber and the standard fiber. Incorporation of antimicrobial constituent in accordance with this invention does not affect the visual appearance of the fiber. Feel of the fiber: The antimicrobial enriched acrylic fiber as prepared in accordance with this invention offers the same feel effect as is observed in case of plain acrylic fiber without any antimicrobial constituent (Also referred as standard). Another important concern in textile industry is dye-ability of the fabric, which is tested by comparing the dyeability of the antimicrobial constituent enriched fabric and the standard acrylic fabric. Dyeability of the antimicrobial enriched acrylic fibers as prepared in accordance with this invention remains the same as that of the standard acrylic fiber. The invention will now be described with the help of the following non-limiting examples. Examples Example 1 Example 1A- Preparation of micro emulsion Myristyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 2-Methyl-4-isothiazolin-3-one, water, phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester were added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 525 ml and Sodium thiocyanate (250 gm) to obtain (803 gm) of aqueous phase. The aqueous phase (803 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1078 gm). Example 1 B- Preparation of fiber (1078 gm) of micro-emulsion as prepared in Example 1A was mixed at 50°C with acrylic Polymer Dope containing 5000gm of acrylic polymer and 16670 gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Preform mass was spun in a bath containing 12.5% of Sodium thiocyanate solution. The temperature of the bath was maintained at -2.5°C. Thereafter, the fiber was cold stretched, gel treated at pH 2.8 at 45°C, then hot stretched at 90°C. The void in the fibers was removed by treating the fiber at 125°C. Fiber is then relaxed and annealed at 120°C and then taken up for post-treatments and was spun into fiber. The acrylic fiber thus obtained contained micro-reservoirs having the entrapped releasable thermoregulatory constituents. Although the micro reservoirs did not have any specific shape or size, they were found to be uniformly distributed throughout the body of the fiber. Example 2 Example 2A- Preparation of micro emulsion Stearyl (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT]was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase. The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm). Example 2 B- Preparation of fiber (1103 gm) of micro-emulsion as prepared in Example 2A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and the fiber was obtained by the process as described in example 1. Example 3 Example 3 A- Preparation of micro emulsion Stearyl alcohol (200gm) and Polyvinyl laurate (50 gm) were heated upto 50°C to obtain a molten mixture. To this 100 gm of chloroquinaldol was added to form a non-aqueous phase (350gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 30 gm ) was dissolved and stirred in water 525 ml and Sodium thiocyanate (250 gm) to obtain (805 gm) of aqueous phase. The aqueous phase (805 gm) was heated to the temperature of the molten non¬aqueous phase (350 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1155 gm). Example 3B- Preparation of fiber (1155 gm) of micro-emulsion as prepared in Example 3A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and the fiber was prepared by the process as described in example 1. Example 4 Example 4A- Preparation of micro emulsion Stearyl (200gm) and paraffin wax (50 gm) were heated upto 50°C to obtain a molten mixture. To this 75 gm of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester) were added to form a non-aqueous phase (325gm) Sulfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) (40gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (840 gm) of aqueous phase. The aqueous phase (840 gm) was heated to the temperature of the molten non¬aqueous phase (325 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1165 gm). Example 4B- Preparation of fiber (1165 gm) of micro-emulsion as prepared in Example 4A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Example 5 Example 5 A- Preparation of micro emulsion Stearyl alcohol (300 gm) and Myristyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 100 gm of 5-chloro-2-(2,4- dichlorophenoxy)phenol (triclosan) was added to form a non-aqueous phase (450gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 60 gm ) was dissolved and stirred in water 640ml and Sodium thiocyanate (250 gm) to obtain (950 gm) of aqueous phase. The aqueous phase (950 gm) was heated to the temperature of the molten non¬aqueous phase (450 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1400gm). Example 5 B- Preparation of fiber (1400gm) of micro-emulsion as prepared in Example 5A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Example 6 Example 6 A- Preparation of micro emulsion Stearyl alcohol (200gm) and Myristyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 80 gm of clotrimazole was added to form a non-aqueous phase (330gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 35 gm ) was dissolved and stirred in water 540 ml and Sodium thiocyanate (250 gm) to obtain (825 gm) of aqueous phase. The aqueous phase (825 gm) was heated to the temperature of the molten non¬aqueous phase (330 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1155gm). Example 6 B- Preparation of fiber (1155 gm) of micro-emulsion as prepared in Example 6A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Example 7 Example 7A- Preparation of micro emulsion Myristyl alcohol (250gm) was heated upto 50°C to obtain a molten mixture. To this 40 gm of chloroquinaldol was added to form a non-aqueous phase (290gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 35 gm ) was dissolved and stirred in water 540 ml and Sodium thiocyanate (250 gm) to obtain (825 gm) of aqueous phase. The aqueous phase (825 gm) was heated to the temperature of the molten non¬aqueous phase (290 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1115 gm). Example 7 B- Preparation of fiber (1115 gm) of micro-emulsion as prepared in Example 7A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Example 8 Example 8 A- Preparation of micro emulsion cetyl alcohol (250 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of p-chloro-m-xylenol was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase. The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm). Example 8B- Preparation of fiber (1103 gm) of micro-emulsion as prepared in Example 8A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1. Example 9 Example 9A- Preparation of micro emulsion Stearyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT]was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase. The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm). Example 9 B- Preparation of fiber (1103 gm) of micro-emulsion as prepared in Example 9A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1. Example 10 Example 10 A- Preparation of micro emulsion Stearyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of p-chloro-m-xylenol was added to form a non-aqueous phase (275gm). Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase. The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm). Example 10 B- Preparation of fiber (1103 gm) of micro-emulsion as prepared in Example 10A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1. 27 Testing procedures: The antimicrobial acrylic products as prepared in the above examples (1 to 10) were tested by using following test procedures: 1) Linear Density (Denier) of the acrylic Fibers was determined by using standard ASTM Test Method (D 1577). The denier of the standard acrylic fiber (without any antimicrobial constituents) and anti-microbial acrylic fibers as prepared in accordance with example 1B was found to be uniform(1.5 denier) irrespective of the type and quantity of the antimicrobial constituent. 2) Tensile strength and Young's modulus of acrylic fiber samples were tested on an Instron tensile testing machine as per the ASTM CI557-03 procedure at ambient temperature. 3) Emulsion stability: The stability of micro-emulsions as prepared in the above examples was evaluated by keeping the same under observation in measuring cylinders for 3 days. During this period no phase separation was observed. 4) Feel of the fabric: The acrylic fabrics as prepared in the above examples and standard fabric (acrylic fabric without antimicrobial constituents), were randomly given to twenty subjects and they were asked to evaluate the texture and feel of the fiber. The test fiber material was interchanged several times amongst the human subjects. Collective results as submitted by the human subjects confirmed that nobody could distinguish between the antimicrobial acrylic fabrics prepared in accordance with the Examples provided above and the standard fabric. 5) Dyeability: The antimicrobial acrylic fabrics as prepared in the above examples and the standard fabric as described above were dyed uniformly with reactive dyes. No noticeable difference as to the Dyeability of the two respective acrylic fabrics, with and without antimicrobial constituent was reported. 6) Visual appearance of the antimicrobial acrylic fiber was evaluated by methods as prescribed in AATCC 124. As far as parameters like % Loss in Dry Tenacity and % loss in dry elongation are concerned, these remained the same( The antimicrobial constituent enriched acrylic fabrics as prepared in the above examples can be tested for antimicrobial activity by various test procedures which include antimicrobial assays used to determine or confirm the effectiveness of treatments applied to medical devices, medical and commercial textiles, and other products. Test methods for measuring the antimicrobial activity include ASTM, AATCC, and other modified methods. Testing includes antibacterial and antifungal activity, with both qualitative and quantitative assays available. AATCC 100 (Part I) is a quanlitative test for antibacterial activity. Test acrylic fiber/fabric specimens are placed into contact with a nutrient agar which has been streaked with a microbe such as Staphylococcus aureus, Escherichia coli bacterial culture. Samples are inoculated with Staphylococcus and evaluated for percent reduction of the bacteria over selected contact periods of 1 — 24 hours. Turnaround Time is usually 5 days. The specimens are then incubated at a temperature 37 °C for a period of time of 24 hours. After the 24 hour incubation period, the samples are visually checked for the growth of bacteria. The AATCC 147, Part III protocol provides a qualitative test for antifungal activity. Acrylic fiber/ fabric specimens are subjected to the growth of a common fungus, Aspergillus niger, on Sabouraud Dextrose agar. Prewet specimens are inoculated and incubated at 28 C for seven days. Specimens are then assessed for growth of the fungus. ASTM E2180-01 test method is used for testing inhibitory mold activity of the acrylic product (fiber /fabric) prepared in accordance with this invention. All the specimen acrylic fiber and fabrics as obtained in examples 1 to 10 were tested for antimicrobial activity by following the above mentioned test protocols. The results of the above mentioned test protocols are provided in the following tables: 'Percentage kill of bacteria' is as per AATCC 100 test method and 'test results' are as per AATCC 147, not observed means no growth of said bacteria was observed on the sample. Table 1 Antimicrobial Activity of Acrylic Fibers Sr. No. % kill of bacteria Test Results Example 1 Microbe tested : S. aureus 99.8 Not Observed Example 2 Microbe tested : S. aureus 100 Not Observed Example 3 Microbe tested : E. coli 100 Not Observed Example 4 Microbe tested : S. aureus 100 Not Observed Example 5 Microbe tested : E. coli 100 Not Observed Example 7 Microbe tested : S. aureus 100 Not Observed Example 8 Microbe tested : S. aureus 100 Not Observed Example 9 Microbe tested : S. aureus 100 Not Observed Example 10 Microbe tested : S. aureus 100 Not Observed Table 2 Antimicrobial Activity of Acrylic Fabric Sr. No. % kill of bacteria Test Results Example 1 Microbe tested : S. aureus 99.8 Not Observed Example 2 Microbe tested : S. aureus 100 Not Observed Example 3 Microbe tested : E. coli 100 Not Observed Example 4 Microbe tested : S. aureus 100 Not Observed Example 5 Microbe tested : E. coli 100 Not Observed Example 7 Microbe tested : S. aureus 100 Not Observed Example 8 Microbe tested : S. aureus 100 Not Observed Example 9 Microbe tested : S. aureus 100 Not Observed Example 10 Microbe tested : S. aureus 100 Not Observed The acrylic fiber and fabric acrylic fabric specimens obtained in examples 6 and 9 contained antifungal agent and their antifungal activity was determined by AATCC 147 part III and in case of the all the specimens no fungal growth was observed meaning that all the specimen exhibited excellent antifungal activity. Furthermore, inhibitory mould activity of these specimens was tested by ASTM E 2180-01 test protocol and good inhibitory activity against Aspergillus niger was recorded. While considerable emphasis has been placed herein on the specific steps of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. We Claim: 1. An antimicrobial acrylic formulation meant for manufacture of acrylic products comprising : ■ at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation, ■ at least one water insoluble antimicrobial constituent soluble said solvent, in the range of about 0.001 to 3.5% of the mass of the formulation, ■ at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40, in the range of 0.001 to 3% of the mass of the formulation, ■ a solvent for acrylic polymer in the range of 20 to 60% of the mass of the formulation, ■ acrylic polymer in the range of about 1 to 15% of the mass of the formulation, and ■ water in the range of about 5% to 60 % with respect to the mass of the formulation. 2. A formulation as claimed in claim 1, wherein the antimicrobial constituent is at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3- one, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy- benzoic acid and propyl ester), o- (2-naphthyl) methyl (3-methylphenyl) thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenol, 4,5-dichloro-n- octyl-4-isothiazoline-3-one[DCOIT], 2-n-octyl-4-isothiazolin-3-one, 1- phenoxy propan-2-ol, pentachlorophenol, 5-chloro-2-dichlorophenoxy phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol. 3. A formulation as claimed in claim 1, wherein the solvent is at least one solvent selected from a group of solvents consisting of C10-C44 alkanes (paraffinic hydrocarbons), polyethylene, polypropylene, polypropylene glycol, polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, polyesters, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils, mineral oil paraffins and diethylphthalate 4. A formulation as claimed in claim 1, wherein the surfactant is at least one non-ionic or anionic surfactant selected from a group of non-ionic or anionic surfactants consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol. 5. A formulation as claimed in claim 8, wherein the ethoxylated alkyl phenoxy and alkyl ethoxylates,non-ionic surfactant is at least one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether, Nonylphenol-polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether, Polyoxyethylene(10) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether, Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether, Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene( 100) nonylphenyl ether, 34 Polyoxyethylene(150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol 15-mole ethoxylate), Surfonic N-"200 (nonylphenol 20-mole ethoxylate) , Surfonic N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17 (ethoxylated and propoxylated linear primary 12-14 carbon number alcohol), Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic DNP-40, fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters,. 6. A formulation as claimed in claim 1, wherein the preferred HLB value of the surfactant is 16 and 40. 7. A formulation as claimed in claim 1, wherein the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm. 8. An antimicrobial acrylic fiber manufactured from a formulation as claimed in claim 1. 9. An antimicrobial acrylic yarn manufactured from a formulation as claimed in claim 1. 10.An antimicrobial acrylic fabric manufactured from a formulation as claimed in claim 1. 1 LA process of preparation of a antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps : ■ admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent, to form a non-aqueous phase ; ■ heating the non-aqueous phase upto 95°C; ■ dissolving and stirring a surfactant, optionally with a co-surfactant, a solvent for acrylic polymer in water to obtain an aqueous phase; ■ heating the aqueous phase; ■ mixing the aqueous phase with the non-aqueous phase in liquid state to form an admixture, and homogenizing to obtain a micro-emulsion; ■ mixing the micro-emulsion with an acrylic polymer solution in a solvent and water and further homogenizing and dispersing the micro-emulsion to obtain a polymer dope wherein the antimicrobial constituent is embedded in evenly dispersed micro-reservoirs. ,rd Dated this 3ra day of July, 2008. Mohan Dewan of R. K. Dewan and Co. Applicants' Patent Attorney

Full Text

FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
ACRYLIC ANTIMICROBIAL FIBER AND A METHOD OF MAKING
THEREOF

ADITYA BIRLA SCIENCE & TECHNOLOGY CO. LTD.
an Indian Company of Aditya Birla Center, 2nd floor, C Wing, S. K. Ahire Marg, Mumbai 400 025,
Maharashtra, India

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

Field of the invention
The present invention relates to textile fibers.
Background of the invention
The term "fiber" or "textile fiber" means a substance which is capable of being spun into a yarn or made into a fabric by bonding or by interlacing in a variety of methods including weaving, knitting, braiding, felting, twisting, or webbing, and which is the basic structural element of textile products.
Fibers are classified on the basis of their length such as short fibers or staple fiber and long fibers or filament fiber. The fibers can also be classified on the basis of their origin such as natural fibers and man-made fibers. The term natural fibers means any fiber that exists as such in the natural state e.g. vegetable fibers or wood fibers. The other type of fibers is obtained from chemical substances. These are called man made fibers. They are rayon, polyester, nylon, acrylic (cashmilon) etc. For centuries, mankind has relied upon various plants and animals to provide raw materials for fabrics and clothing. In recent times, the industrialization and scientific advancement has provided several improved materials having far superior properties, particularly suitable for clothing.
Acrylic fibers are synthetic fibers containing at least 85% of acrylonitrile
monomer. The acrylic fibers are prepared from a polymer Polyacrylonitrile which
is obtained by free radical polymerisation with an average molecular weight of
-100,000. Typical properties of acrylic fibers include, resistance to moths, oils, and
chemicals. Furthermore, they are also resistant to deterioration from sunlight
exposure.
The process steps involved in the preparation of Acrylic fibers are as follows:
2

The acrylic polymer is dissolved in solvents like N,N-dimethylformamide or aqueous sodium thiocyanate. Then it is metered through a multi-hole spinnerette and the resultant filaments are coagulated in an aqueous solution of the same solvent. The resultant filaments are washed, stretched, dried and crimped to obtain final acrylic fibers. Acrylic fibers are typically produced in a range of deniers from 1 to 15.
Acrylic is lightweight, soft, and warm, with a wool-like feel. It dyes very well and has excellent colorfastness. It is resilient, retains its shape, and resists shrinkage and wrinkles. Acrylic fibers are commonly used in sweaters, hand-knitting yarns, rugs, awnings, boat covers, and beanies; the fiber is also used as a precursor for carbon fiber.
From the spun or filament yarn, fabric is formed by knitting or weaving operations. Knitted fabrics can be made by using hooked needles to interlock one or more sets of yarns through a set of loops. The loops may be either loosely or closely constructed, depending on the purpose of the fabric. Knitted fabrics can be used for hosiery, underwear, sweaters, slacks, suits, coats, rugs and other home furnishings. Knitting is performed using either weft or warp processes.
Some typical preparations that are involved in the weaving operations are warping, slashing or sizing. Sizing agents are added to the yarn by solution or pad/dry techniques. Differences in raw materials, processing chemicals, fiber diameter, post treatments and blend ratios can be manipulated, to produce a fiber having customized properties suitable for desired application. It is often desired that the acrylic fabrics possess typical properties such as thermal stability, ability to retain perfumes, antibacterial properties and the like. These properties are essential in several industrial as well as household applications. There has been a considerable

interest in developing such materials. In order to impart various desirable properties to the fabric as mentioned above to the fabric, several constituents with various properties are added. Such constituents include antimicrobial agents, deodorizing agents, antistatic agents, perfumes. Besides such specific constituents, generic constituents for improving overall quality of the fabric, such as sizing agents, antimicrobial constituents for increasing yarn softness and pliability are also added.
Prior Art
US patent 5405644 discloses a process of manufacturing an antimicrobial fiber which involves mixing of silver-containing inorganic microbicide composition with fiber material which is further dipped in discoloration inhibitor containing solution.
The process as disclosed in US 6368361 involves contacting and immersing the fiber in an aqueous solution containing a cationic surfactant with a quaternary ammonium salt group, a water-soluble protein, and an alkaline compound are dissolved. The fiber is then separated from the aqueous solution and immersed in another aqueous solution containing tea polyphenol which is an antimicrobial agent.
A composite textile fabric involving a blend of two fabric layers wherein one of the fabric layers is coated with an antimicrobial agent such as silver and copper sulfide is disclosed in US Patent 6194332.

20040247653 discloses a process of preparing an antimicrobial and antiviral polymeric material which involves embedding microscopic water insoluble powder particles of ionic copper oxide into the polymer material.
US 4649078 discloses a lower temperature technique for incorporating antimicrobial agents into the fibers which involves passing the fiber into a liquid containing an antimicrobial agent such as bis(tri-n-butyl tin)oxide, n-trichloromethylthio phthalimide, n-(2-methylnaphthyl)maleimide, 2,4-dichlorobenzyl alcohol and 2-(n-octyl-4-isothiazolin-3-one.
US 3959556 discloses method of preparation of improved composite antimicrobial yarns which involves extruding a spinnable solution of a synthetic thermoplastic resin and an antimicrobial agent. The antimicrobials are selected from a group consisting of 2,4,4'-trichloro-2'-hydroxydiphenyl ether; 2,2'-methylenebis- (3,4,6-trichlorophenol); and 2,2'-thiobis (4,6-dichlorophenol).
US 6436419 discloses a method for preparing antimicrobial polymer which involves coating of a polymer with an acid dye attached with an quaternary ammonium salt (antimicrobial agent).
Earlier known processes of incorporating such antimicrobial constituents, as reported in the above mentioned patents/applications, mainly involved conventional methods like spraying, encapsulating, solvent spinning the antimicrobial constituents on the fabric. However, these methods suffer from several disadvantages which include non-uniform and improper adhesion of antimicrobial constituents onto the fiber material and gradual washing out of the antimicrobial constituents over a period of time and which affects the feel and texture of the fabric.

There is thus felt a need for a process of incorporating antimicrobial constituents into fabric which overcomes these shortcomings.
Objects of the Invention
It is an object of this invention to provide antimicrobial acrylic fibers, wherein at least one antimicrobial constituent is incorporated in the body of the fiber.
Another object of this invention is to provide a process of incorporating antimicrobial constituents into acrylic fibers which ensures uniform distribution of the antimicrobial constituent throughout the fiber length.
Yet another object of this invention is to provide antimicrobial acrylic fibers wherein the antimicrobial constituents are retained in the acrylic product over a prolonged period of time.
Yet another object of this invention is to provide a process of incorporating antimicrobial constituents to acrylic fibers which does not affect the feel and texture of the fabric.
Still another object of this invention is to provide a process of incorporating antimicrobial constituents to acrylic fibers such that inherent properties of the acrylic fibers such as fiber strength, linear density, tenacity, heat resistance, dyeability and drying properties are not altered.
6

Definitions:
As used in the present specification, the following words and phrases are generally
intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise.
"Non-aqueous phase" means a melted mixture in liquid state which is water
insoluble.
"Aqueous phase" means substance dissolved in water.
"Acrylic Polymer dope" means regular acrylic and modacrylic polymers, containing atleast 35% acrylonitrile as a monomer for modacrylic and 85%) for regular acrylic polymer. The other comonomers can be methylacrylate, ethyl vinyl ether, vinyl bromide, vinyl chloride, vinyledene chloride, vinyl acetate, vinyl sulfonic acid, itaconic acid, and/or methylmethacrylate and sulfonated monomers such as sodium styrene sulfonate, sodium methallyl sulfonate, sodium sulfophenyl methallyl ether.
"Preform mass" means an intermediate material suitable for making fibers.
Summary of the Invention
In accordance with this invention there is provided an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising:
• at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation,
7

• at least one water insoluble antimicrobial constituent soluble in said solvent, said constituent being in the range of about 0.001 to 3.5% of the mass of the formulation,
• at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40,said surfactant being in the range of 0.001 to 3% of the mass of the formulation,
• acrylic polymer in the range of about 1% to 15% of the mass of the formulation,
• water in the range of about 50% to 90 % of the mass of the formulation.
Typically, the antimicrobial constituent is at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester), o-(2-naphthyl) methyl (3-methylphenyl) thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenoI,4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT] 2-n-octyl-4-isothiazolin-3-one, 1-phenoxy propan-2-ol, pentachlorophenol, 5-chloro-2-dichlorophenoxy phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol.
Typically, the solvent is at least one solvent selected from a group of solvents consisting of C10-C44 alkanes (paraffmic hydrocarbons), polyethylene, polypropylene, polypropylene glycol, polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, polyesters, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated

hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils ,mineral oil paraffins and diethylphthalate.
Typically, the surfactant is at least one non-ionic or anionic surfactant selected from a group of non-ionic or anionic surfactants consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol
Typically, the phenoxy like ethoxylated non-ionic or anionic surfactant is at least
one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether,
Nonylphenol polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether,
Polyoxyethylene(l0) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether,
Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether,
Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene(l00) nonylphenyl
ether, Polyoxyethylene( 150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2-
ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol
9.5-mole ethoxylate) ,Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl
phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) ,
Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol
15-mole ethoxylate), Surfonic N-200 (nonylphenol 20-mole ethoxylate) , Surfonic
N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole
ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17
(ethoxylated and propoxylated linear primary 12-14 carbon number alcohol),
Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic
DNP-40 , fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene

sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters.
In accordance with one preferred embodiment of the invention, the HLB value of the surfactant is between 16 and 40.
In accordance with one aspect of the invention, the antimicrobial constituent, the solvent and the surfactant are processed to form micro-reservoirs which are embedded into the body of the formulation.
Typically, the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm.
The invention also extends to an antimicrobial acrylic fiber, yarn and fabric manufactured from a formulation in accordance with this invention.
In accordance with this invention there is also provided a process for preparation of an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps :
• admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent followed by heating the resulting admixture upto 95°C to obtain a non-aqueous phase;
• dissolving and stirring a surfactant, optionally with a co-surfactant, in water to obtain an aqueous phase;
• admixing and homogenizing the non-aqueous phase with the aqueous phase to obtain a micro-emulsion;

dispersing the micro-emulsion throughout the mass of the acrylic polymer dope to obtain a preform mass wherein the antimicrobial constituent is in the form of evenly dispersed micro-reservoirs.
Typically, the pH of the aqueous phase is in the range of 7 to 13.
Typically, the amount of non-aqueous phase in the micro-emulsion is in the range of 0.1 to 40% of the mass of the micro-emulsion.
Typically, the amount of surfactant in the micro-emulsion is in the range of 0.1 to 20% of the mass of the micro-emulsion.
Typically, the proportion of antimicrobial constituent in the acrylic product is in the range of 0.001 to 5% with respect to the mass of the acrylic product.
Typically, the solvent for polyacrylonitrile is at least one selected from a group consisting of sodium thiocyanate , dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, ethylene carbonate, aqueous zinc chloride and aqueous nitric acid. The polymer percentages in the acrylic dope will vary depending on the solvent For dimethyl formamide, acrylic polymer concentration soluble in polymer dope is as high as 28-32%; for dimethyl acetamide, it is as high as 22-27%; for dimethyl sulfoxide, it is as high as 20-25%; for ethylene carbonate, it is as high as 15-18%, for aqueous nitric acid, it is as high as 8-12% and for zinc chloride, it is as high as 8-12%. For Sodium thiocyanate as a solvent, acrylic polymer concentration is as high as 10-15%.

Brief Description of the accompanying Drawings:
The invention will be described in detail with reference to the accompanying
drawings.
In the accompanying drawing, Figure 1 illustrates the block diagram showing the method steps involved in the process in accordance with this invention.
Figure 2 illustrates the cross-sectional view of antimicrobial acrylic fibers prepared in accordance with this invention which shows uniform distribution of micro-reservoirs of antimicrobial constituents entrapped across the length of the fibers.
Detailed Description:
Acrylic fibers were the first viable manufactured fibers. The reason behind the
most widespread use of these fibers lies in their versatility. Furthermore, these
fibers also have peculiar ability to blend easily with many fibers which makes them
the fibers of choice.
Though fibers and fabrics made from them have many desirable properties,
oftentimes, consumers expect performance characteristics beyond those for which
fibers were designed. In order to meet with these increasing expectations, various
antimicrobial constituents are incorporated in the acrylic fibers. There has been a
considerable interest in developing such materials.
One of the additional desirable properties of acrylic fibers which has enormous
demand is "antimicrobial activity".
In accordance with this invention there is provided an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising:

• at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation,
• at least one water insoluble antimicrobial constituent soluble in said solvent, said constituent being in the range of about 0.001 to 3.5% of the mass of the formulation,
• at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40,said surfactant being in the range of 0.001 to 3% of the mass of the formulation,
• acrylic polymer in the range of about 1% to 15% of the mass of the formulation,
• water in the range of about 50% to 90 % of the mass of the formulation.
In accordance with the invention, anti-microbial constituent is typically at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester), o- (2-naphthyl) methyl (3-methylphenyl) thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenol, 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT], 2-n-octyl-4-isothiazolin-3-one, 1-phenoxy propan-2-oI, pentachlorophenol, 5-chloro-2-dichlorophenoxy phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol.
The antimicrobial constituent impart antimicrobial property to the fibers and ultimately to the fabric or garments made from these fibers.
In accordance with this invention , only non-aqueous solvent is used which is typically selected from a group of solvents consisting of C10-C44 alkanes (paraffinic hydrocarbons), polyethylene, polypropylene, polypropylene glycol,
13

polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils, mineral oil paraffins and diethylphthalate.
Preferably, paraffin wax either alone or in combination with stearyl alcohol is used as the non-aqueous solvent.
In accordance with this invention only water soluble non-ionic or anionic surfactant/co-surfactant is used. Typically, the non-ionic or anionic surfactant is selected from a group consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol. Typically, the alkyl phenoxy ethoxylated non-ionic or anionic surfactant is at least one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether, Nonylphenol polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether, Polyoxyethylene(l0) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether, Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether, Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene(l00) nonylphenyl ether, Polyoxyethylene(150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) ,

Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol 15-mole ethoxylate), Surfonic N-200 (nonylphenol 20-mole ethoxylate) , Surfonic N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17 (ethoxylated and propoxylated linear primary 12-14 carbon number alcohol), Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic DNP-40, fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters.
The non-ionic or anionic surfactant is selected such that the lipophilic portion of the non-ionic or anionic surfactant is compatible with the antimicrobial constituent and the surfactant forms oil in water microemulsion. Surfactants with HLB values within the range of 9 to 40 are used. Preferably, non-ionic or anionic surfactants with HLB values more than 13 are used.
In accordance with one preferred embodiment of the invention, the HLB value of the surfactant is between 16 and 40.
In accordance with one aspect of the invention, the antimicrobial constituent, the solvent and the surfactant are processed to form micro-reservoirs which are embedded into the body of the formulation. The antimicrobial acrylic contains uniformly dispersed micro-reservoirs throughout the body of the fibers. The micro-reservoirs are discrete, nano-sized structures without any definite geometrical shape.

Typically, the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm.
The invention also extends to an antimicrobial acrylic fiber, yarn and fabric manufactured from a formulation in accordance with this invention.
In accordance with this invention there is also provided a process for preparation of an antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps :
• admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent followed by heating the resulting admixture upto 95°C to obtain non-aqueous phase ;
• dissolving and stirring a surfactant, optionally with a co-surfactant, in water to obtain an aqueous phase;
• admixing and homogenizing the non-aqueous phase with the aqueous phase to obtain a micro-emulsion;
• dispersing the micro-emulsion throughout the mass of the acrylic polymer dope to obtain a preform mass wherein the antimicrobial constituent is in the form of evenly dispersed micro-reservoirs.
Typically, the pH of the aqueous phase is in the range of 7 to 13.
Typically, the amount of non-aqueous phase in the micro-emulsion is in the range of 0.1 to 40% of the mass of the micro-emulsion.
Typically, the amount of surfactant in the micro-emulsion is in the range of 0.1 to 20% of the mass of the micro-emulsion.

Typically, the proportion of antimicrobial constituent in the acrylic product is in the range of 0.001 to 5% with respect to the mass of the acrylic product.
Before arriving at the optimum concentration of the surfactant to be used, cloud point of the aqueous phase is determined. Furthermore, alkalinity of the aqueous phase matches with that of the acrylic polymer dope thereby avoiding any drastic change in the alkalinity during the emulsification and homogenization step.
Typically, the melted non-aqueous phase containing antimicrobial constituent in a non-aqueous solvent along with aqueous phase containing surfactants is emulsified using high speed mixers such as Ultraturrex or a mechanical emulsifier; a colloid mill; a high pressure homogenizer and an ultrasonic emulsifier to form a microemulsion. The micro-emulsion may contain further additional antimicrobial constituents, if desired.
It is important that the non-aqueous phase is maintained in liquid state throughout the mixing process. The aqueous phase therefore is typically heated upto a particular temperature to ensure that the temperature of the resulting emulsion is above the melting point of the non-aqueous solvent. If this does not happen, the resulting emulsion will break down.
The active ingredients are released from the micro-reservoir into the acrylic matrix. The structure of micro-reservoir, acrylic and surrounding conditions determine the release rate of the antimicrobial constituent. The molecules of the volatile antimicrobial constituents migrate from micro-reservoirs to the surrounding primarily by diffusion. The antimicrobial constituent is released from the matrix in a controlled release manner.

Preform mass is spun to fiber in a bath containing 12.5% of Sodium thiocyanate solution. The temperature of the bath is maintained at -2.5°C. Thereafter, the fiber is cold stretched, gel treated at pH 2.8 at 45°C, then hot stretch at 90°C. The void in the fibers is removed by treating the fiber at 125°C. Fiber is then relaxed and annealed at 120 C and then taken up for post-treatment.
The acrylic fibers can be further subjected to post treatment to make fabric which
typically involves:
o Convert to Yarn in blend or pure
o Convert to Warp Beam
o Sizing
o Fabric Manufacturing- Weaving /Knitting
o Dyeing
o Finishing
Alternatively, the filaments so obtained are further blended using standard equipment. The blended fibers are laid in to a web using standard equipment followed by Consolidation of the web to obtain Non-woven Acrylic Fabric. The acrylic product made from the formulation in accordance with this invention contains uniformly dispersed micro-reservoirs throughout the mass which is shown in Fig. 2.
The antimicrobial constituent enriched acrylic fabrics as prepared in the above examples can be tested for antimicrobial activity by various test procedures which include antimicrobial assays used to determine or confirm the effectiveness of treatments applied to medical devices, medical and commercial textiles, and other products. Test methods for measuring the antimicrobial activity include ASTM, AATCC, and other modified methods. Testing includes antibacterial and antifungal activity, with both qualitative and quantitative assays available.

AATCC 100 is a qualitative test for antibacterial activity.
Test acrylic fiber/fabric specimens are placed into contact with a nutrient agar which has been streaked with a microbe such as Staphylococcus aureus, Escherichia coli bacterial culture. Samples are inoculated with Staphylococcus and evaluated for percent reduction of the bacteria over selected contact periods of 1 -24 hours. Turnaround Time is usually 5 days. The specimens are then incubated at a temperature 37 °C for a period of time of 24 hours. After the 24 hour incubation period, the samples are visually checked for the growth of bacteria.
The AATCC 174, Part III protocol provides a qualitative test for antifungal
activity. Acrylic fiber/ fabric specimens are subjected to the growth of a common
fungus, Aspergillus niger, on Sabouraud Dextrose agar. Prewet specimens are
inoculated and incubated at 28 °C for seven days. Specimens are then assessed for
growth of the fungus.
ASTM E2180-01 test method is used for testing inhibitory mold activity of the acrylic product (fiber /fabric) prepared in accordance with this invention.
The antimicrobial acrylic fibers contain the entrapped antimicrobial constituent in releasable form. Microscopic examination of the micro-reservoirs in the acrylic fibers is shown in Fig 2.
The resultant acrylic fabric containing antimicrobial constituent are tested. Linear Density (Denier) of the acrylic Fibers is determined by using standard ASTM Test Method (D 1577). The denier of the standard acrylic fiber (acrylic fiber without any antimicrobial constituents) and anti-microbial enriched acrylic fiber remains the same. Thus addition of antimicrobial constituents does not change the linear density of the acrylic fibers.

Tensile strength and Young's modulus of acrylic fiber sample is tested on an Instron tensile testing machine as per the ASTM CI557-03 procedure at ambient temperature.
Visual appearance of the antimicrobial enriched fiber is evaluated by methods as prescribed in AATCC 124. As far as parameters like % Loss in Dry Tenacity and % loss in dry elongation are concerned, these remain the same in the antimicrobial enriched acrylic fiber and the standard fiber. Incorporation of antimicrobial constituent in accordance with this invention does not affect the visual appearance of the fiber.
Feel of the fiber: The antimicrobial enriched acrylic fiber as prepared in accordance with this invention offers the same feel effect as is observed in case of plain acrylic fiber without any antimicrobial constituent (Also referred as standard).
Another important concern in textile industry is dye-ability of the fabric, which is tested by comparing the dyeability of the antimicrobial constituent enriched fabric and the standard acrylic fabric. Dyeability of the antimicrobial enriched acrylic fibers as prepared in accordance with this invention remains the same as that of the standard acrylic fiber.
The invention will now be described with the help of the following non-limiting examples.

Examples Example 1
Example 1A- Preparation of micro emulsion
Myristyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 2-Methyl-4-isothiazolin-3-one, water, phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester were added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 525 ml and Sodium thiocyanate (250 gm) to obtain (803 gm) of aqueous phase.
The aqueous phase (803 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1078 gm).
Example 1 B- Preparation of fiber
(1078 gm) of micro-emulsion as prepared in Example 1A was mixed at 50°C with acrylic Polymer Dope containing 5000gm of acrylic polymer and 16670 gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass. Preform mass was spun in a bath containing 12.5% of Sodium thiocyanate solution. The temperature of the bath was maintained at -2.5°C. Thereafter, the fiber was cold stretched, gel treated at pH 2.8 at 45°C, then hot stretched at 90°C. The void in the fibers was removed by treating the fiber at 125°C. Fiber is then relaxed and annealed at 120°C and then taken up for post-treatments and was spun into fiber.
The acrylic fiber thus obtained contained micro-reservoirs having the entrapped releasable thermoregulatory constituents. Although the micro reservoirs did not

have any specific shape or size, they were found to be uniformly distributed throughout the body of the fiber.
Example 2
Example 2A- Preparation of micro emulsion
Stearyl (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT]was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase.
The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm).
Example 2 B- Preparation of fiber
(1103 gm) of micro-emulsion as prepared in Example 2A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and the fiber was obtained by the process as described in example 1.
Example 3
Example 3 A- Preparation of micro emulsion
Stearyl alcohol (200gm) and Polyvinyl laurate (50 gm) were heated upto 50°C to obtain a molten mixture. To this 100 gm of chloroquinaldol was added to form a non-aqueous phase (350gm) Surfonic N-400 nonylphenol 40-mole ethoxylate

(surfactant) ( 30 gm ) was dissolved and stirred in water 525 ml and Sodium thiocyanate (250 gm) to obtain (805 gm) of aqueous phase. The aqueous phase (805 gm) was heated to the temperature of the molten non¬aqueous phase (350 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1155 gm).
Example 3B- Preparation of fiber
(1155 gm) of micro-emulsion as prepared in Example 3A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and the fiber was prepared by the process as described in example 1.
Example 4
Example 4A- Preparation of micro emulsion
Stearyl (200gm) and paraffin wax (50 gm) were heated upto 50°C to obtain a molten mixture. To this 75 gm of 2-Methyl-4-isothiazolin-3-one, water, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-benzoic acid and propyl ester) were added to form a non-aqueous phase (325gm) Sulfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) (40gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (840 gm) of aqueous phase.
The aqueous phase (840 gm) was heated to the temperature of the molten non¬aqueous phase (325 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1165 gm).

Example 4B- Preparation of fiber
(1165 gm) of micro-emulsion as prepared in Example 4A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass.
Example 5
Example 5 A- Preparation of micro emulsion
Stearyl alcohol (300 gm) and Myristyl alcohol (50 gm) were heated upto 50°C to
obtain a molten mixture. To this 100 gm of 5-chloro-2-(2,4-
dichlorophenoxy)phenol (triclosan) was added to form a non-aqueous phase
(450gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 60 gm )
was dissolved and stirred in water 640ml and Sodium thiocyanate (250 gm) to
obtain (950 gm) of aqueous phase.
The aqueous phase (950 gm) was heated to the temperature of the molten non¬aqueous phase (450 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1400gm).
Example 5 B- Preparation of fiber
(1400gm) of micro-emulsion as prepared in Example 5A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass.
Example 6
Example 6 A- Preparation of micro emulsion
Stearyl alcohol (200gm) and Myristyl alcohol (50 gm) were heated upto 50°C to
obtain a molten mixture. To this 80 gm of clotrimazole was added to form a

non-aqueous phase (330gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 35 gm ) was dissolved and stirred in water 540 ml and Sodium thiocyanate (250 gm) to obtain (825 gm) of aqueous phase. The aqueous phase (825 gm) was heated to the temperature of the molten non¬aqueous phase (330 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1155gm).
Example 6 B- Preparation of fiber
(1155 gm) of micro-emulsion as prepared in Example 6A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass.
Example 7
Example 7A- Preparation of micro emulsion
Myristyl alcohol (250gm) was heated upto 50°C to obtain a molten mixture. To this 40 gm of chloroquinaldol was added to form a non-aqueous phase (290gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 35 gm ) was dissolved and stirred in water 540 ml and Sodium thiocyanate (250 gm) to obtain (825 gm) of aqueous phase.
The aqueous phase (825 gm) was heated to the temperature of the molten non¬aqueous phase (290 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1115 gm).
Example 7 B- Preparation of fiber
(1115 gm) of micro-emulsion as prepared in Example 7A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass.

Example 8
Example 8 A- Preparation of micro emulsion
cetyl alcohol (250 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of p-chloro-m-xylenol was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase.
The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm).
Example 8B- Preparation of fiber
(1103 gm) of micro-emulsion as prepared in Example 8A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1. Example 9
Example 9A- Preparation of micro emulsion
Stearyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of 4,5-dichloro-n-octyl-4-isothiazoline-3-one[DCOIT]was added to form a non-aqueous phase (275gm) Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase.
The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm).

Example 9 B- Preparation of fiber
(1103 gm) of micro-emulsion as prepared in Example 9A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1.
Example 10
Example 10 A- Preparation of micro emulsion
Stearyl alcohol (200gm) and cetyl alcohol (50 gm) were heated upto 50°C to obtain a molten mixture. To this 25 gm of p-chloro-m-xylenol was added to form a non-aqueous phase (275gm).
Surfonic N-400 nonylphenol 40-mole ethoxylate (surfactant) ( 28 gm ) was dissolved and stirred in water 550 ml and Sodium thiocyanate (250 gm) to obtain (828 gm) of aqueous phase.
The aqueous phase (828 gm) was heated to the temperature of the molten non¬aqueous phase (275 gm) and both the phases were homogenized in a high speed mixer (Ultraturrex) to obtain a micro-emulsion (1103 gm).
Example 10 B- Preparation of fiber
(1103 gm) of micro-emulsion as prepared in Example 10A was mixed at 50°C with acrylic Polymer Dope containing 5000 gm of acrylic polymer and 16670gm of sodium thiocyanate and 20000 ml of water were added to obtained preform mass and fiber was obtained by the process as described in example 1.
27

Testing procedures:
The antimicrobial acrylic products as prepared in the above examples (1 to 10) were tested by using following test procedures:
1) Linear Density (Denier) of the acrylic Fibers was determined by using standard
ASTM Test Method (D 1577).
The denier of the standard acrylic fiber (without any antimicrobial constituents) and anti-microbial acrylic fibers as prepared in accordance with example 1B was found to be uniform(1.5 denier) irrespective of the type and quantity of the antimicrobial constituent.
2) Tensile strength and Young's modulus of acrylic fiber samples were tested on an Instron tensile testing machine as per the ASTM CI557-03 procedure at ambient temperature.
3) Emulsion stability: The stability of micro-emulsions as prepared in the above examples was evaluated by keeping the same under observation in measuring cylinders for 3 days. During this period no phase separation was observed.
4) Feel of the fabric: The acrylic fabrics as prepared in the above examples and standard fabric (acrylic fabric without antimicrobial constituents), were randomly given to twenty subjects and they were asked to evaluate the texture and feel of the fiber. The test fiber material was interchanged several times amongst the human subjects. Collective results as submitted by the human subjects confirmed that nobody could distinguish between the antimicrobial acrylic fabrics prepared in accordance with the Examples provided above and the standard fabric.
5) Dyeability: The antimicrobial acrylic fabrics as prepared in the above
examples and the standard fabric as described above were dyed uniformly

with reactive dyes. No noticeable difference as to the Dyeability of the two respective acrylic fabrics, with and without antimicrobial constituent was reported.
6) Visual appearance of the antimicrobial acrylic fiber was evaluated by methods as prescribed in AATCC 124. As far as parameters like % Loss in Dry Tenacity and % loss in dry elongation are concerned, these remained the same( The antimicrobial constituent enriched acrylic fabrics as prepared in the above examples can be tested for antimicrobial activity by various test procedures which include antimicrobial assays used to determine or confirm the effectiveness of treatments applied to medical devices, medical and commercial textiles, and other products. Test methods for measuring the antimicrobial activity include ASTM, AATCC, and other modified methods. Testing includes antibacterial and antifungal activity, with both qualitative and quantitative assays available.
AATCC 100 (Part I) is a quanlitative test for antibacterial activity. Test acrylic fiber/fabric specimens are placed into contact with a nutrient agar which has been streaked with a microbe such as Staphylococcus aureus, Escherichia coli bacterial culture. Samples are inoculated with Staphylococcus and evaluated for percent reduction of the bacteria over selected contact periods of 1 — 24 hours. Turnaround Time is usually 5 days. The specimens are then incubated at a temperature 37 °C for a period of time of 24 hours. After the 24 hour incubation period, the samples are visually checked for the growth of bacteria.

The AATCC 147, Part III protocol provides a qualitative test for antifungal
activity. Acrylic fiber/ fabric specimens are subjected to the growth of a common
fungus, Aspergillus niger, on Sabouraud Dextrose agar. Prewet specimens are
inoculated and incubated at 28 C for seven days. Specimens are then assessed for
growth of the fungus.
ASTM E2180-01 test method is used for testing inhibitory mold activity of the acrylic product (fiber /fabric) prepared in accordance with this invention.
All the specimen acrylic fiber and fabrics as obtained in examples 1 to 10 were tested for antimicrobial activity by following the above mentioned test protocols. The results of the above mentioned test protocols are provided in the following
tables:
'Percentage kill of bacteria' is as per AATCC 100 test method and 'test results' are as per AATCC 147, not observed means no growth of said bacteria was observed on the sample.
Table 1
Antimicrobial Activity of Acrylic Fibers
Sr. No. % kill of bacteria Test Results
Example 1
Microbe tested : S. aureus 99.8 Not Observed
Example 2
Microbe tested : S. aureus 100 Not Observed
Example 3
Microbe tested : E. coli 100 Not Observed
Example 4
Microbe tested : S. aureus 100 Not Observed
Example 5
Microbe tested : E. coli 100 Not Observed
Example 7
Microbe tested : S. aureus 100 Not Observed
Example 8
Microbe tested : S. aureus 100 Not Observed
Example 9
Microbe tested : S. aureus 100 Not Observed
Example 10
Microbe tested : S. aureus 100 Not Observed

Table 2
Antimicrobial Activity of Acrylic Fabric
Sr. No. % kill of bacteria Test Results
Example 1
Microbe tested : S. aureus 99.8 Not Observed
Example 2
Microbe tested : S. aureus 100 Not Observed
Example 3
Microbe tested : E. coli 100 Not Observed
Example 4
Microbe tested : S. aureus 100 Not Observed
Example 5
Microbe tested : E. coli 100 Not Observed
Example 7
Microbe tested : S. aureus 100 Not Observed
Example 8
Microbe tested : S. aureus 100 Not Observed
Example 9
Microbe tested : S. aureus 100 Not Observed
Example 10
Microbe tested : S. aureus 100 Not Observed
The acrylic fiber and fabric acrylic fabric specimens obtained in examples 6 and 9 contained antifungal agent and their antifungal activity was determined by AATCC 147 part III and in case of the all the specimens no fungal growth was observed meaning that all the specimen exhibited excellent antifungal activity. Furthermore, inhibitory mould activity of these specimens was tested by ASTM E 2180-01 test protocol and good inhibitory activity against Aspergillus niger was recorded.

While considerable emphasis has been placed herein on the specific steps of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim:
1. An antimicrobial acrylic formulation meant for manufacture of acrylic
products comprising :
■ at least one non-aqueous solvent in the range of about 0.01 to 7% of the mass of the formulation,
■ at least one water insoluble antimicrobial constituent soluble said solvent, in the range of about 0.001 to 3.5% of the mass of the formulation,
■ at least one water soluble nonionic surfactant having HLB value in the range of 9 to 40, in the range of 0.001 to 3% of the mass of the formulation,
■ a solvent for acrylic polymer in the range of 20 to 60% of the mass of the formulation,
■ acrylic polymer in the range of about 1 to 15% of the mass of the formulation, and
■ water in the range of about 5% to 60 % with respect to the mass of the formulation.
2. A formulation as claimed in claim 1, wherein the antimicrobial constituent
is at least one selected from a group consisting of 2-Methyl-4-isothiazolin-3-
one, Phenoxyethanol Benzoic acid, 4-Hydroxy-methyl ester, Hydroxy-
benzoic acid and propyl ester), o- (2-naphthyl) methyl (3-methylphenyl)
thiocarbamate, 5-chloro-2-(2,4-dichlorophenoxy)phenol, 4,5-dichloro-n-
octyl-4-isothiazoline-3-one[DCOIT], 2-n-octyl-4-isothiazolin-3-one, 1-
phenoxy propan-2-ol, pentachlorophenol, 5-chloro-2-dichlorophenoxy
phenol, clotrimazole, p-chloro-m-xylenol and chloroquinaldol.

3. A formulation as claimed in claim 1, wherein the solvent is at least one solvent selected from a group of solvents consisting of C10-C44 alkanes (paraffinic hydrocarbons), polyethylene, polypropylene, polypropylene glycol, polytetramethylene glycol, polypropylene malonate, polyneopentyl glycol sebacate, polypentane glutarate, polyvinyl myristate, polyvinyl stearate, polyvinyl laurate, polyhexadecyl methacrylate, polyoctadecyl methacrylate, polyethylene oxides, polyethylene glycols, Arachidyl alcohol, behenyl alcohol, Selachyl alcohol, chimimyl alcohol, polyesters, di-iso decyl phthalate, benzyl alcohol, C4 -C30 aliphatic alcohols ,C4 -C30 saturated hydrocarbons, C4 -C30 monounsaturated hydrocarbons, natural oils, mineral oil paraffins and diethylphthalate
4. A formulation as claimed in claim 1, wherein the surfactant is at least one non-ionic or anionic surfactant selected from a group of non-ionic or anionic surfactants consisting of alkyl phenoxy ethoxylated non-ionic surfactants and ethoxylated alkyl alcohol surfactants, Polyethylene-block-Poly propylene glycol-block-polyethylene glycol and Ethylenediamine tetrakis(propylene oxide-block-ethylene oxide) tetrol.
5. A formulation as claimed in claim 8, wherein the ethoxylated alkyl phenoxy and alkyl ethoxylates,non-ionic surfactant is at least one selected from a group consisting of Polyoxyethylene(8) isooctylphenyl ether, Nonylphenol-polyethylene glycol ether, Polyoxyethylene(9) nonylphenyl ether, Polyoxyethylene(10) isooctylphenyl ether, Polyoxyethylene(12) nonylphenyl ether, Polyoxyethylene(12) isooctylphenyl ether, Polyoxyethylene(40) nonylphenyl ether, Polyoxyethylene(40) isooctylphenyl ether, Polyoxyethylene( 100) nonylphenyl ether,
34

Polyoxyethylene(150) dinonylphenyl ether, Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-95(Poly (oxy-1, 2-ethanediyl), alpha- (nonyl phenyl)-omega-hydroxyl-glycol ether) ( nonylphenol 9.5-mole ethoxylate) , Surfonic N-120(nonylphenol 12-mole ethoxylate) , Surfonic N-150 (nonylphenol 15-mole ethoxylate), Surfonic N-"200 (nonylphenol 20-mole ethoxylate) , Surfonic N-300( nonylphenol 30-mole ethoxylate) , Surfonic N-400 nonylphenol 40-mole ethoxylate, Surfonic LF-7 (Alkyl polyoxyalkylene ether) , Surfonic LF-17 (ethoxylated and propoxylated linear primary 12-14 carbon number alcohol), Igepal CO-630 (nonylphenoxy poly(ethyleneoxy)ethanol,branched), Surfonic DNP-40, fatty alcohol ether sulfates, alkyl carboxylates, alkyl benzene sulfonates, sulfosuccinates, polyethanoxy ether sulphate esters and polyethanoxy ether phosphate esters,.
6. A formulation as claimed in claim 1, wherein the preferred HLB value of the surfactant is 16 and 40.
7. A formulation as claimed in claim 1, wherein the average mean size of the micro-reservoir is in the range of 5 nm to 2000 nm.
8. An antimicrobial acrylic fiber manufactured from a formulation as claimed in claim 1.
9. An antimicrobial acrylic yarn manufactured from a formulation as claimed in claim 1.

10.An antimicrobial acrylic fabric manufactured from a formulation as claimed in claim 1.
1 LA process of preparation of a antimicrobial acrylic formulation meant for manufacture of acrylic products comprising the following steps :
■ admixing a water-insoluble antimicrobial constituent with a non-aqueous solvent, to form a non-aqueous phase ;
■ heating the non-aqueous phase upto 95°C;
■ dissolving and stirring a surfactant, optionally with a co-surfactant, a solvent for acrylic polymer in water to obtain an aqueous phase;
■ heating the aqueous phase;
■ mixing the aqueous phase with the non-aqueous phase in liquid state to form an admixture, and homogenizing to obtain a micro-emulsion;
■ mixing the micro-emulsion with an acrylic polymer solution in a solvent and water and further homogenizing and dispersing the micro-emulsion to obtain a polymer dope wherein the antimicrobial constituent is embedded in evenly dispersed micro-reservoirs.

,rd
Dated this 3ra day of July, 2008.

Mohan Dewan
of R. K. Dewan and Co.
Applicants' Patent Attorney

Documents:

1394-mum-2008-abstract.doc

1394-mum-2008-abstract.pdf

1394-MUM-2008-ANNEXURE TO FORM 3(26-9-2012).pdf

1394-MUM-2008-CLAIMS(AMENDED)-(26-9-2012).pdf

1394-mum-2008-claims.doc

1394-mum-2008-claims.pdf

1394-MUM-2008-CORRESPONDENCE(13-04-2010).pdf

1394-mum-2008-correspondence(18-7-2008).pdf

1394-MUM-2008-CORRESPONDENCE(24-7-2009).pdf

1394-MUM-2008-CORRESPONDENCE(28-6-2013).pdf

1394-mum-2008-correspondence.pdf

1394-mum-2008-description(complete).doc

1394-mum-2008-drawing.pdf

1394-MUM-2008-EP DOCUMENT(26-9-2012).pdf

1394-mum-2008-form 1(18-7-2008).pdf

1394-MUM-2008-FORM 1(28-6-2013).pdf

1394-MUM-2008-FORM 1(MARKED COPY)-(28-6-2013).pdf

1394-mum-2008-form 1.pdf

1394-MUM-2008-FORM 18(24-7-2009).pdf

1394-mum-2008-form 2(titel page).pdf

1394-mum-2008-form 2.doc

1394-mum-2008-form 2.pdf

1394-MUM-2008-FORM 26(26-9-2012).pdf

1394-MUM-2008-FORM 3(13-04-2010).pdf

1394-mum-2008-form 3(3-7-2008).pdf

1394-mum-2008-form 3.pdf

1394-MUM-2008-MARKED COPY(26-9-2012).pdf

1394-MUM-2008-PETITION UNDER RULE-137(28-6-2013).pdf

1394-MUM-2008-REPLY TO EXAMINATION REPORT(26-9-2012).pdf

1394-MUM-2008-SPECIFICATION(AMENDED)-(26-9-2012).pdf

1395-mum-2008-discription(complete).pdf

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Patent Number

256675

Indian Patent Application Number

1394/MUM/2008

PG Journal Number

29/2013

Publication Date

19-Jul-2013

Grant Date

15-Jul-2013

Date of Filing

03-Jul-2008

Name of Patentee

ADITYA BIRLA SCIENCE & TECHNOLOGY CO. LTD.

Applicant Address

ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI,

Inventors:

#	Inventor's Name	Inventor's Address
1	LODHA PREETI	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,
2	MAHAJAN TUSHAR	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,
3	KAPOOR BIR	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,
4	LODHA PREETI	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,
5	MAHAJAN TUSHAR	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,
6	KAPOOR BIR	ADITYA BIRLA CENTRE, 2ND FLOOR, C WING, S.K. AHIRE MARG, MUMBAI-400 025,

PCT International Classification Number

A01N25/34

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1		1900-01-01	Not Selected