Title of Invention

"NOVEL PIGMENT COMPOSITION AND PROCESS FOR THE PREPARATION THEREOF"

Abstract

The present invention relates to novel pigment compositions for use in textile printing based on novel alkali swellable cross-linked organic polymer having both hydrophilic and hydrophobic segments and to processes for the preparation thereof. The synthetic thickener is provided in the form of an emulsion polymer using processors available in the form of emulsion which also gives thickening effect.

Full Text

A PROCESS FOR THE PREPARATION OF NOVEL COPOLYMERS. Field of the Invention The present invention relates to a process for the preparation of such novel alkali swellable crosslinked organic polymer for use as thickener or thickener cum binder in pigment compositions. The present invention also relates to methods of printing employing the novel pigment compositions. The present invention also relates to novel pigment compositions containing novel thickeners for use in textile printing and the processes for the preparation thereof. In particular, the present invention relates pigment compositions for use in textile printing based on novel alkali swellable cross-linked organic polymer having both hydrophilic and hydrophobic segments. Background of the invention Thickener for imparting consistency and/or high viscosity to textile printing compositions are well known in the art. Thickened paste used for textile printing (localized coloration) is expected to display good flow on application offeree (movement of the applicator) and a restricted flow on removal of application force for enabling obtainment of sharp prints. Further textile prints are expected to display reasonable level of wash fastness properties. Fabric prints are more acceptable if they have soft and smooth feel besides excellent brightness Thickener which is one of the most important ingredients of the print paste is a very major contributor for all the three critical print properties mentioned above. In fact, due to these very requirements thickening systems consisting of oil (mineral turpentine oil) emulsified in water have gained considerable popularity in pigment printing work. After printing, the printed components of the thickening system namely MTO and water get evaporated leaving only the binder polymer on the fabric besides the pigment and thus leading to prints with high brightness plus a soft and smooth handle. The processors do not give any washing treatment to the pigment printed fabric made with the oil in water emulsion thickener and the same is packed and dispatched to the market. However, the use of oil in water emulsion thickener system leads to a number of major problems e.g. high air and water pollution, risk of explosion and fire. Any thickener for use in pigment printing work has therefore to be highly efficient and practically insoluble in wash liquor so that the handle, brightness and wash fastness. meet the requirements and expectations. With increasing cost of MTO and hydrocarbon oils any alternative thickener is also expected to afford decrement in cost of thickening. A number of natural polymers (starch, cellulose, gums, polysachharides) by themselves or in the form of their derivatives have been attempted as pigment printing thickeners without much success. They give prints, which are stiff/harsh and dull and do not have adequate wash fastness. Thus, the search for acceptable pigment printing thickener leads to specially designed synthetic polymers having high thickening efficiency and less stiffness. Since the pigment has no substantivity to the fabric, use of a binder is a must. One of the approaches therefore consists of use of binder which also doubles up as thickener. It has been demonstrated that bocks (chemical groups) which are responsible for giving high thickening efficiency also give rise to products of high glass transition temperature Tg (stiffness). Hence, a number of different polymer having various combinations of monomers have been attempted for obtaining the best balance of properties. Besides the chemical structure and the ratio of monomers employed, the properties of polymer are mainly governed by the molecular weight and its distribution. Molecular weight and its distribution are in turn governed by the procedure/technique employed for preparation of the polymer e.g. bulk/solution or emulsion polymerization technique. Each method further has its own limitation for e.g. in emulsion polymerization, solubility of monomers in water and reactivity ratios, as well as the feeding schedule have a decisive influence on the molecular weight and its distribution. Hence, polymer of same chemical structure may display an entirely different set of properties. For these reasons, a large number of synthetic polymers in different forms have been reported for application as thickeners for pigment printing. The most successful commercial products are available in the form of light fluffy powders, or as thick pastes in high boiling hydrocarbons/alcohols as such or as their ethylene oxide derivatives. However, none of the commercially successful products is based on emulsion polymerization. In principle, the advantages of emulsion polymerization process namely ease of handling and highest molecular weight development have not been exploited folly and thoroughly. Inverse emulsion systems and use of polymerisable surfactants have lead to some promising products. Description of prior art Prior art methods of printing of textiles with pigments employ oil in water emulsion thickening systems along with latex type binder. The obtained prints display excellent colour yield and brightness coupled with adequate fastness to washing, rubbing and dry-cleaning. These positive features coupled with soft handle have made this system the most preferred technology for the said use. Increasing awareness regarding the environment pollution and consequent stricter enforcement of stringent regulations all over the world have made it mandatory to printers to shift to eco-friendly alternatives. Natural and modified natural thickeners used in printing of reactive disperse and acid dyes/colouring matters are not suitable for pigment printing due to their inadequate viscosity at low concentration and flow behavior under shearing conditions. The applicability of aqueous based synthetic polymers has been explored for exploiting their beneficial effects. A number of synthetic polymeric thickeners have been developed with rheological properties similar to oil in water emulsion thickening. Different systems have been evolved replacing partially or completely the oil part. Commercially traded pigment printing thickeners are available in the form of powder or as pourable paste. Most of synthetic thickening agents are polymers and copolymer capable of developing high viscosity as a consequence of partial or total neutralization. The low solubility or insolubility of these un-neutralised polymers in water, enable to obtain dispersion or emulsion or solution in water in relatively high concentration displaying low viscosity. Polymer systems of this property have been known for a long time and they have been in various physical forms, enabling ease of usage. Aqueous solutions of uncross-linked poly (meth) acrylic acicU are known to impart high viscosity to aqueous systems at somewhat higher concentration and hence not preferred in pigment printing. Powder type thickening agents are also known to be containing cross-linked polymers having monoethylenecally unsaturated acid groups. However, these powders are fluffy in nature and take longer time for complete swelling. GB Patent No. 870,994 discloses the use of a water swellable emulsion copolymer containing 25 to 70 percent by weight of methacrylic acid, at least 10 percent by weight of a copolymerised lower acrylate component and up to 40 percent by weight of other copolymerised neutral monoethylenically unsaturated monomers. However, this emulsion suffered from the disadvantage that there was a high risk of "shock" or coagulation of the dispersed materials at the time of mixing of the acid thickener with the system to be thickened or during the addition of alkaline material. US Patent No. 3,894,980 attempts to solve this problem by providing a thickener, an aqueous dispersion of water-insoluble linear emulsion copolymer of about 15 to 40 percent by weight of acrylic acid or methacrylic acid, about 20 to 60 percent by weight of one or more acrylic acid esters and about 10 to 65 percent by weight of a C2 to C8 alkyl acrylate. Synthetic thickeners reported in this Patent are high molecular weight polymers containing substantial proportion of mono ethylenically unsaturated acidic monomer. On neutralization of the acidic moiety, carboxylate anions are formed. These repel each other causing uncoiling of the polymer and resulting in swelling and increasing in viscosity. Several other components eg. ethylenically unsaturated esters, amide, nitriles and other vinyl monomers have been employed for preparation of thickening agents for this propose. In short a suitable thickener for pigment printing, is required to have high viscosity at lowest connection and should display pseudoplastic behavior. Electrolyte insensitivity of the polymeric thickener is very desirable as some of the components of printing paste, say, water may contain electrolytes. While this patent does overcome the disadvantages of the prior art, it would have been highly desirable if the thickener could also double up as a binder. Also, the process in question could have been more economical. As will be aware to a person skilled in the art most of synthetic thickening agents are polymers and copolymer capable of developing high viscosity as a consequence of partial or total neutralization. The low solubility or insolubility of these un-neutralised polymers in water enable production of dispersion or emulsion or solution in water in relatively high concentration displaying low viscosity. Polymer systems of this property have been known for a long time and they have been in various physical forms, enabling ease of usage. Aqueous solutions of uncross-linked poly (meth) acrylic acids are known to impart high viscosity to aqueous systems at some what higher concentration and hence not preferred in pigment printing. Powder type thickening agents are also known to contain cross-linked polymers having monoethylenically unsaturated acid groups. However, these powders are fluffy in nature and take longer time for complete swelling. Unlike small molecular weight polymeric compounds the properties of the polymers are governed by molecular weight besides the nature of the building blocks, monomers. The molecular weight is governed by the synthesis technique for manufacture. The nature of the products as well as their properties are therefore, highly dependent upon the technique employed for their preparations. The various polymerization techniques yield the product in various physical forms and molecular weight. Emulsion polymerization Co-polymers with hydrophobic monomers like esters of (meth) acrylic acid, styrene etc and hydrophilic monomers like acrylic acid, methacrylic acid, itaconic acid are the products of commercial interest due to their wide application in paints, adhesives, binders, thickeners etc. Generally emulsion or emulsifier free emulsion polymerization technique is used for their synthesis. By this technique high molecular weight polymers are obtained with fairly low viscosity with better control of exothermicity of the polymerization. Strictly speaking, the polymerization of above system is not truly an emulsion polymerization process. A two loci mechanism is proposed by J.L. Guillame et al (J. of Poly Sci. Polym. Chem, 26,1937, (1988) This suggests that rate of reaction depends up on local concentration of monomer(s). For such systems theory of homogeneous particles is also applicable. This theory suggests that oligomeric particles are formed in the aqueous phase in the initial stage of polymerization which precipitate after attaining certain critical molecular weight and act as primary particles (Bajaj et al J. Appl. Polym. Sci 53 (13) 1771 (1994). The stability of emulsion is dependent on factors like temperature, chemical nature and concentration of the monomers, chemical nature of the surfactants and agitator speed and design used for polymerization. Flocculation of particles can occur after attaining certain critical size, which then become unstable. Sufficient adsorbed surfactant prevents flocculation. Particle size distribution of the emulsion is affected by emulsifier concentration, temperature of polymerization, ratio of hydrophilic to hydrophobic monomers, feed policy and feed rate etc. Inverse Emulsion Polymerization Inverse emulsion technique yields viscous latex consisting of hydrophilic polymer particles swollen by water in the continuous phase. In this technique, polymerization is done in non-aqueous solvent. Effect of polymerization conditions like initiator concentration, cross-linking agent, monomers pH, and temperature etc on thickening properties of polyacrylic acid system has been studied. Latex having good electrolyte resistance can be obtained by polymerization with non-ionic hydrophobes at a selected pH. For preparation of thickeners by inverse emulsion process, hydrophilic monomers like ethylenically unsaturated acids and amides are employed. Use of hydrophobic monomers like Hexadecyl methacrylate. Dodecyl methacrylate have also been reported. Agglomerated particles can be achieved by azeotropic distillation of organic solvent after polymerization. Heat sensitive thickeners are prepared by inverse emulsion technique from n-isopropyl acrylamide using methylene bisacryl amide as cross-linking agent in presence of sorbitan monooleate in hexane solvent. The disadvantages of inverse polymerization technique are (1) the use of costly organic solvent (2) the extra cost of solvent recovery step (3) extra step of conversion of polymer powder to an aqueous dispersion. In suspension polymerization technique, every dispersed monomer droplet acts as a tiny bulk reactor. These droplets are very active for agglomeration. Suspending agents, stirrer speed, and stirrer design play an important role in preventing agglomeration. By solution and precipitation polymerization technique comparatively low molecular weight polymers are obtained which show poor rheological properties. Solvents like benzene, ethyl acetate, cyclohexane etc have been used. N.N. dimethyl acrylamide and dimethyl aminopropyl methacrylamide with PEG dimethacrylate have been polymerized in water. Polyacrylic acid thickeners produced by precipitation polymerization in organic solvent display high thickening effect. In precipitation polymerization of acrylic based thickeners organic solvents like cyclohexane is mostly used. In the solvent, monomers are soluble while the polymers are insoluble. Crosslinked N-substituted acrylamide, acrylic acid copolymer thickeners having improved performance in alkaline condition have been documented in prior art. Enhanced performance thickeners: Optimization of copolymer composition and concentration of crosslinking agent has not enabled these thickeners to display a comparable performance to oil in water emulsion thickeners. Selection of comonomers and crosslinking agent are crucial. Copolymers of methacrylic acid and ethyl acrylate have better thickening properties than other combinations. But bad smell and effect of EA on human health have led to its replacement by methyl methacrylate. MAA-MMA based thickeners exhibit very low swelling properties due to their high Tg. During neutralization by a base, the thickener gets swelled and tend to drown the stirrer shaft with gel formation. This happens to all polymers having low swelling properties and this is known as Weissenberg effect. The use of surfactant monomers (USRE 33,008) such as monoester of ethyxylate hepadecanol (US patent 4, 616,074) or polyoxysorbate (EP 658,579) etc. has been reported to improved swelling properties as well as electrolyte stability. Unlike small molecular weight polymeric compounds the properties of the polymers are governed by molecular weight besides the nature of the building blocks, monomers. The molecular weight is governed by the synthesis technique for manufacture. The nature of the products as well as their properties are therefore very dependent upon techniques employed for their preparations. The various polymerization techniques yield the product in various physical forms and molecular weight. Objects of the invention It is therefore, an object of the present invention to provide novel acrylic based alkali swellable polymers for use as thickeners in textile printing. It is another object of the present invention to provide a novel acrylic based alkali swellable polymers for use as thickeners cum binders in textile printing. It is another object of the present invention to provide novel bisegmented polymers having enhanced thickening, binding and leveling hi aqueous systems, useful in pigment printing of textiles. It is further object of the present invention to provide a process for the preparation of a novel acrylic based alkali swellable polymers for use as thickeners/thickener cum binders in textile printing. It is yet another object of the present invention to provide a novel pigment composition for use in printing of textiles as well as a process for the preparation thereof. Summary of the invention The present invention achieves the objects of the invention by development of synthetic thickener in the form of an emulsion polymer. This approach is quite interesting from the point of view of the fact that processors are used to employing binders, which are available in the form of emulsion and would welcome if the same chemical also gives thickening effect. Otherwise they may prefer another thickener which is available in the easily handled emulsion form. Powder form thickener is somewhat difficult to handle since it is either fluffy or is coated and in that case, takes long tune to swell. Printers tend to use more than the desired quantity of the thickener because of the time lag. When increased quantity of powder form synthetic thickener is used, stiffness of the handle occurs and the cost of thickening increases. For making paste form thickener, one employs the powder thickener and a high boiler solvent cum softener which are not necessary ingredients as far as printing process is concerned and special equipment are required for paste making. Thus, the search for synthetic thickener in the emulsion form is continuing and is justified. Accordingly, the present invention provides a process for the preparation of novel copolymers for use as thickeners and/binders in textile printing which comprises copolymerising (a) at least 10 % by wt of a carboxylic acid of the kind such as herein described with (b) up to 90 % by wt of one or more comonomers consisting of vinyl compounds or mixtures thereof. The present invention also provides a pigment composition for use in textile printing which comprises up to 20 % by wt of a conventional pigment or dye, up to 20 % by wt of a binder and up to 20 % by wt of a thickener, the balance comprising of water, wherein said thickener comprises a copolymer consisting of (a) at least 10 % by wt of a carboxylic acid of the kind such as herein described with (b) up to 90 % by wt of one or more comonomers consisting of vinyl compounds or mixtures thereof. The present invention further provides a process for the preparation of a pigment composition for use in textile printing, which comprises mixing a copolymer comprising of (a) at least 10 % by wt of a carboxylic acid of the kind such as herein described with (b) up to 90 % by wt of one or more comonomers consisting of vinyl compounds or mixtures thereof with a conventional binder and water to obtain a stock paste, and mixing a conventional pigment to said stock paste, the amount of said copolymer being up to 20 % by wt, the amount of said binder being up to 20 % by wt and the amount of said pigment being up to 20% by wt, the pH of said composition being in the range of from 8 to 9.5 Detailed description of the Invention Tailor making of the polymer can give good thickening and leveling properties in water borne coatings and printing pastes. The present invention will be described in greater detail with reference to preferred embodiments. In a preferred embodiment, said one or more carboxylic acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, and mixture thereof. Preferably, said of one or more comonomers consisting of vinyl compounds is selected from esters and amides of acrylic, methacrylic, itaconic acid, maleic acid, acrylonitrile, methacrylonitrile, styrene, methyl styrene, a- methyl styrene, vinyl toluene, vinyl and vinylidene halides, vinyl acetate, vinyl esters and ethers, butadiene and isoprene or mixtures thereof. Preferably, said one or more carboxylic acid monomer is present in amount of from 20 to 50 wt %. In another preferred embodiment, said one or more comonomers consisting of vinyl compounds are selected from C1 - C4 alkyl acrylates or methacrylate or maleate or mixtures thereof. Preferably, said one or more comonomers consisting of vinyl compounds are present in an amount of from 50 to 80 wt %. In a most preferred embodiment, said one or more carboxylic acid monomer is added at a later part of the reaction in order to obtain higher alkaline viscosity at lower active solid content of the polymer. In another preferred embodiment, said copolymerisation is carried out in the presence of a free radical initiator, selected preferably, from ammonium or alkali metal persulphates. The amount of said free radical initiator is conveniently, from 0.01 to 1 wt %. The reaction temperature is preferably, in the range of 50 to 100°C. Said polymerisation is preferably, carried out in the presence of an emulsifier selected from a mixed ionic and non-ionic surfectant system. Preferably, said emulsifier is present in an amount of 0.5 to 5 % by wt. The present invention also envisages a novel process for printing textiles. Particularly, the present invention encompasses within its scope a process for printing textiles which comprises printing patterns on a textile in any conventional manner employing a pigment composition characterized in that said pigment composition comprises up to 20 % by wt of a conventional pigment or dye, up to 20 % by wt of a binder and up to 20 % by wt of a thickener, the balance comprising of water, wherein said thickener comprises a copolymer consisting of (a) at least 10 % by wt of a carboxylic acid of the kind such as herein described with (b) up to 90 % by wt of one or more comonomers consisting of vinyl compounds or mixtures thereof. In a most preferred embodiment of the present invention copolymerization is carried out as under employing: 1. at least 10% by weight of one or more monomers selected from methacryclic acid, acrylic acid, itaconic acid, fumaric acid and crotonic acid. 2. maximum 90% weight of co-monomers, consisting of vinyl compounds or mixtures thereof, selected from esters and amide of the acrylic, methacrylic, itaconic acids, acrylonitrile, methacrylonitirle, styrene, alpha methyl styrene, vinyl toluene, vinyl and vinydilene halides, butadiene and isoprene, vinyl esters and ethers. The copolymers of the present system are crosslinked up to various degrees. In this case, the copolymers comprise from 0 to 2% by wt of one or more polyunsaturated monomers, such as ethylene glycol dimethacrylate, allyl methacrylate methylene bis acrylamide and di allyl phthalate, di allyl maleate, hydroxymethyl acrylamide, hydroxymethyl methacrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate etc. Preferred components of this system are: i). (Meth) acrylic acid ii). Acrylates having 2 to 25 carbon atoms in the pendant group It is within the scope of the present invention to prepare said copolymers by emulsion polymerization technique by means of free radical mechanism with a polymeric solid content up to 40% on the total weight. A mixed ionic and non ionic surfactant system is used as emulsifying agent, preferably in the range of 0.5 to 5% by wt related to monomers. Among the radical polymerization initiators, ammonium or alkali metal persulfates, are used, prferably in amounts of 0.01 to 1% by wt related to the monomers. Temperature can preferably be in the range of from 50 to 100°C. The invention provides a polymeric latex obtained by polymerization in aqueous emulsion of a monomeric system of: a. 20-50% by wt of (meth) acrylic acid b. 40-70% by wt of alkyl acrylates having 2 to 5 carbon atoms in ester part. c. 0 to 2% by wt of one more polyunsaturated compounds. One of the major objectives of present invention is to get higher efficiency of the thickening agents by regulating the feeds of co-monomers. The reactivity ratio of (meth) acrylic acid is more than ethyl acrylate in copolymerization (Ph.D Thesis, M. Goyal, IIT, Delhi, 1993). When both acid and ester are fed, due to higher reactivity more acid monomers go to the polymer chain in the initial stage of reaction than the ester comonomer. Thus the copolymer particles obtained have more ester components on the surface. This results to lower thickening ability of the copolymer, and the reason are: 1. Non uniform copolymer chain 2. Hydrophobic esters are present on the surface of the particles, which prevent quick neutralization. In order to get uniform and regular blocks in the polymer chain more part of the acid is added in the later part of the polymerization. This enables more of the acid comonomer to remain on the surface for instant neutralization. It is seen that viscosity almost doubled in the range of solid content for printable viscosity on textile. The copolymers of the invention are used to thicken pastes. Pigment printing is carried out, preferably by adding the copolymers to the system to be thickened and or thickening the mixture by means of neutralization with bases, for example, ammonia or ammonium hydroxide. In the case of pastes for pigment printing already neutralized and ready to use, the adjustment of viscosity is obtained by simple addition of the latex in low amounts not to appreciably change the final pH. In any case, it is possible to thicken the same aqueous system by adding the copolymers in an already partially or completely neutralized from. The present invention will now be described with reference to the following non-limiting Examples, the purpose which is only to illustrate the invention: Example-1 Monomer pre emulsion was prepared by taking 120 gm DM water, 2gm neutralized sulfonated nonyl phenyl ethylene oxide condensate surfactant (anionic surfactant), 2 gm nonyl phenyl ethyele oxide condensate non ionic surfactant, 124 gm methacrylic acid, 176 gm ethyl acrylate, 10 gm di octyl maleate, 2.5 gm di allyl phthalate. Initiator system was prepared with 0.5 gm of potassium persulfate in 80 gm of DMW. 545 gm of DMW mixed with 2 gm of SLS, 2 gm of above said anionic surfactant, and 2 gm of non ionic surfactant (nonyl phenyl ethylene oxide condensate) was taken in reactor tank and temperature of the same was raised to 85°C with agitation. To it the monomer emulsion and ¾th of initiator solution was charged in 3.5 hours as in Exmple-1. 10 minutes after completion of feeding rest of the initiator solution was charged and 1 hour holding time was given at 85°C. Then the latex was cooled and discharged. Example-2 Monomer pre emulsion was prepared taking 252 gm DM water, 0.3 gm sodium lauryl sulfate (SLS), 16.5 gm neutralized sulfonated nonyl phenyl ethylene oxide condensate surfactant (anionic surfactant), 6.2 gm nonyl phenyl ethyele oxide condensate non ionic surfactant, 126 gm methacrylic acid, 250 gm ethyl acrylate. Three sets of initiators were prepared with 2.55 gm of potassium persulfate and 0.5 gm of t-butyl hydroperoxide in 60 gm, 6.5 gm and 2 gm of DMW. 250 gm of DMW mixed with 0.8 gm of SLS, 16 gm of above said anionic surfactant, solution of 0.35 gm of sodium bicarbonate in 30 gm of water was taken in a reactor tank and the temperature was raised to 75°C with agitation. To it monomer emulsion and first initiator system were charged in 3.25 hours. After feedingl hour holding time was given at 80°C. During holding second and third initiator systems were charged in 30 minutes and 15 minutes intervals. Finally, the latex was cooled and discharged. Example-3 Monomer pre emulsion was prepared taking 256.5 gm of DM water, 0.5 gm sodium lauryl sulfate (SLS), 16 gm neutralized sulfonated nonyl phenyl ethylene oxide condensate surfactant (anionic surfactant), 4.3 gm nonyl phenyl ethylene oxide condensate non ionic surfactant, 126 gm methacrylic acid, 250 gm butyl acrylate, 18.75 gm hydroxymethylmethacrylamide. Two sets of initiator systems were prepared with 2.55 gm and 0.4 gm of potassium persulfate in 80 gm and 10 gms of DMW respectively. 225 gm of DMW mixed with 0.9 gm of SLS, 16 gm of above said anionic surfactant, solution of 0.35 gm of sodium bicarbonate in 30 gm of water was taken in a reactor tank and the temperature was raised to 75°C with agitation. To it monomer emulsion and first initiator system were charged in 3.25 hours. After feeding 1 hour holding time was given at 80°C. During holding second initiator system was charged hi 30 minute intervals. Finally, the latex was cooled and discharged. Example-4 Two sets of aqueous emulsions of the monomers, viz., pre-emulsion 1 and pre-emulsion 2 were prepared. Pre-emulsion-1 was prepared consisting of 60 gm demineralized water, 1 gm non ionic surfactant (nonyl phenyl ethylene oxide condensate), 1 gm anionic surfactant (neutralized long chain aryl sulfonic acid), 93 gm ethyl acrylate, 62 gm methacrylic acid and 1.24 gm disllyphathalate. The pre-emulsion-1 was diluted with 50 gm of DM water. Pre-emulsion 2 was prepared consisting of 60 gm DM water, 1 gm anionic surfactant (nonyl pyhenyl ethylene oxide condensate), 1 gm anionic surfactnant neutralized long chain aryl sulfonic acid, 77.5 gm ethyl acrylete, 77. gm methacrlic acid 1.24 gm diallyl phthalate. This emulsion was diluted by 5 gm of DM water. A solution of 445 gm of DM water, 2 gm of sodium sulfate, 2 gms of another nonionic surfactant (neutralized long chain aryl sulfonic acid, (heated to 85°C), 10 gm of 0.65% potassium persulfate aqueous solution were initially added to above solution, then 20 gm of 0.65% potassium persulfate aqueous solution, then 20 gm of 0.65% potassium persulfate aqueous solution and 130 gm of pre-emulsion 1 were charged in 30 minutes duration followed by 168 pre-emulsion 2 in 60 minutes duration. During charging of pre-emulsions, 10 gm of 0.65% potassium persulfate aqueous solution was charged at 30 minutes interval in one shot. After feeding of pre-emulsions, 10 minutes holding time was given and then rest of 0.62% potassium persulfate solution was charged in a single short and again hold for 1 hours at 85°C. Finally, the resulting latex is cooled and discharged. Example-5 a. Pigment printing formulation was prepared by mixing 6 parts of polymer emulsion given in example 1, 9 parts TPI 2135 binder and rest demineralized water to make the volume 100. The pH of the mixture was raised to 8.5 to 9. A thick paste was obtained. b. A stock paste was prepared according to procedure (a) with 5 parts of emulsion of example 2 and 5 parts of TPI 2135. c. A stock paste was prepared according to procedure (a) with 9 parts of emulsion of example 3 and 1 parts of TPI 2135. d. A stock paste was prepared according to procedure (a) with 5 parts of emulsion of example 4 and 9 parts of TPI 2135. e. Deep shade print paste are made by 5 gm of Dyster red pigment to 100 grams of stock paste of a,b,c,d, each of the print pastes are screen printed on cotton fabric, air dried and cured for 5 minutes at 150 C. Prints are evaluated for hand, depth and brightness, wash and crock fastness and rated in scale of 1 to 5, where 5 is best and 1 is worst. The viscosities of stock pastes and print pastes are those obtained by a Brookfield RVT viscometer using spindle no 5 at 20 rpm at room temperature. Evaluation results are given in following table: (Table Removed) We Claim : 1. A process for the preparation of novel copolymers for use as thickeners and/or binders in textile printing which comprises copolymerising (a) at least 10% by wt of one or more carboxylic acid monomer of the kind such as herein described with (b) up to 90% by wt of one or more comonomers consisting of vinyl compounds or mixtures thereof, wherein said copolymerisation is carried out in presence of from 0.01 to 1 wt% of a free radical initiator of the kind such as herein described and from 0.5 to 5% by wt of an emulsifier of the kind such as herein described at a reaction temperature in the range of 50 to 100°C. 2. A process as claimed in claim 1 wherein said one or more carboxylic acid monomer is selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid and fumaric acid and any mixtures thereof. 3. A process as claimed in claim 1 or 2 wherein said one or more comonomers consisting of vinyl compounds is selected from esters and amides of acrylic, methacrylic, itaconic acid, maleic acid, acrylonitrile, methacrylonitrile, styrene, methyl styrene, a-methyl styrene, vinyl toluene, vinyl and vinylidene halides, vinyl acetate, vinyl esters and ethers, butadiene and isoprene or mixtures thereof. 4. A process as claimed in any preceding claim wherein said one or more carboxylic acid monomer is present in amount of from 20 to 50 wt%. 5. A process as claimed in any preceding claim wherein said one or more comonomers consisting of vinyl compounds are selected from Ci-C4 alkyl acrylates or methacrylate or maleate or mixtures thereof. 6. A process as claimed in any preceding claim wherein said one or more comonomers consisting of vinyl compounds are present in an amount of from 50 to 80 wt%. 7. A process as claimed in any preceding claim wherein more amount of said one or more carboxylic acid monomer is added at a later part of the reaction in order to obtain higher alkaline viscosity at lower active solid content of the polymer. 8. A process as claimed in claim 7 wherein said free radical initiator is selected from ammonium or alkali metal persulphates. 9. A process as claimed in any preceding claim wherein said emulsifier is selected from a mixed ionic and non-ionic surfactant system.

Documents:

275-del-2002-abstract.pdf

275-del-2002-claims.pdf

275-del-2002-correspondence-others.pdf

275-del-2002-correspondence-po.pdf

275-del-2002-description (complete).pdf

275-del-2002-form-1.pdf

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275-del-2002-form-2.pdf

275-del-2002-form-3.pdf

275-del-2002-form-4.pdf

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