|Title of Invention||
"A PROCESS FOR MANUFACTURE OF A LAUNDRY DETERGENT BAR"
|Abstract||The present invention relates to an improved process for the manufacture of a laundry detergent bar including the steps of providing at least one detersive surfactant, and at least one adjunct bar ingredient, and mixing the detersive surfactant and the adjunct bar ingredient to form a detergent premix. A shear-sensitive material is added to the detergent premix, and mixed to form a homogenized detergent composition. The homogenized detergent composition is then extruded under shear into the shape of a laundry detergent bar. In this manufacturing process, the shear rate in the extruding step is from about 1 to about 1000 min-1, and the total shear in the homogenization step and the extruding step is from about 300 to about 5000.|
|Full Text||The present invention relates to a process for manufacturing a laundry detergent bar, and a laundry detergent bar made by that process.
In societies where mechanical washing machines are not common, laundry detergent bars comprising synthetic organic surfactants and detergency builders are commonly used in the laundering of clothes. Technical developments in the field of laundry detergent bars have concerned formulating bars which are effective in cleaning clothes; which have acceptable sudsing characteristics in warm and cool water and in hard and soft water; which have acceptable in-use wear rates, hardness, durability, and feel; which have low smear and which have a pleasing odor and appearance. Laundry detergent bar processes are also well known in the art Prior art disclosing laundry detergent bars and laundry detergent bar processes include; U.S. Patent 2,178,370, Okenfuss, issued April 13, 1965; and Philippine Patent 13778 to Anderson, issued September 23,1980.
A laundry detergent bar manufacturing process typically combines a surfactant and various adjunct bar ingredients, such as a builder, dye, chelant, soil suspension agents, etc. to form a highly viscous paste which is then extruded into a bar. In order to ensure proper homogenization of the detergent paste, a high shear is typically employed throughout the entire manufacturing process. A process employing high shear and a high temperature also promotes many desired chemical and binding reactions, such as, for example, neutralization of
an acid surfactant by an alkaline material. A high shear may also be required to properly structure the bar, e.g., to prevent the final laundry detergent bar from being either too soft, or too brittle,
It is known that certain materials, such as bleaches and enzymes may be degraded by the laundry detergent bar manufacturing process. Degradation of these materials is undesirable for aesthetic and cleaning reasons. For example, when an oxygen bleach degrades, it evolves oxygen gas. In a laundry detergent bar, the evolution of gas within the bar may cause undesirable physical characteristics such as bar layering and bar puffing, Furthermore, layered bars can easily crumble during use. In addition, less oxygen bleach is available to bleach the clothes, resulting in a reduction of bleaching activity.
In order to reduce degradation, the typical manufacturing process adds materials such as bleaches and enzymes immediately prior to plodding and/or extrusion. However, it has been found that even with addition immediately prior to extrusion, these materials still undergo degradation. Furthermore, in these processes, the bleach and/or enzyme may not be property homogenized into the bar composition. This results in bars which have an uneven distribution of these materials.
Accordingly, the need remains for an improved process for manufacturing of laundry detergent bars wherein shear-sensitive materials may be successfully incorporated into the laundry detergent bar.
This need is met by the present invention wherein it has now been discovered that the high shear which is present in the typical laundry detergent bar manufacturing process causes the degradation of materials such as bleach and enzymes. Accordingly, such a material is hereinafter described as a "shear-sensitive material." It has also been found that when the shear rate and total shear at extrusion are controlled, the degradation of a shear-sensitive material is significantly reduced.
Accordingly, the present invention relates to an improved process for the manufacture of a laundry detergent bar including the steps of providing at least one detersive surfactant, and at least one adjunct bar ingredient, and mixing the detersive surfactant and the adjunct bar ingredient to form a detergent premix. A shear-sensitive material is added to the detergent premix, and mixed to form a
homogenized detergent composition. The homogenized detergent composition is then extruded under shear into the shape of a laundry detergent bar. In this manufacturing process, the shear rate in the extruding step is from about 1 to about 1000 min-1, and the total shear in the extruding step is from about 300 to about 5000.
According to another embodiment of the present invention, an improved process for the manufacture of a laundry detergent bar includes the steps of providing at least one detersive surfactant, and at least one adjunct bar ingredient, and mixing the detersive surfactant and the adjunct bar ingredient to form a detergent premix. A shear-sensitive material is added to the detergent premix, and mixed in a moderate speed mixer to form a homogenized detergent composition. The homogenized detergent composition is then extruded under shear into the shape of a laundry detergent bar. In this manufacturing process, the shear rate in the extruding step is from about 1 to about 1000 min'1, and the total shear in the extruding step is from about 300 to about 5000.
Another embodiment of the invention includes a laundry detergent bar made by the processes described herein.
These and other features, aspects, and advantages of the present invention will become evident to those skilled in the art from a reading of the present disclosure with the appended claims.
In accordance with the present invention it has now been found that the high shear in the typical laundry detergent bar manufacturing process causes the degradation of materials such as a bleach and enzyme. By controlling the shear rate and total shear, the improved process of the invention significantly reduces the degradation of a shear-sensitive material, resulting in improved cleaning performance and improved bar physical properties.
All percentages, ratios, and proportions herein are by weight, unless otherwise specified. Furthermore, all percentages herein are by weight of the final laundry detergent bar composition, unless specified. All temperatures are in degrees Celsius (°C) unless otherwise specified. All documents cited are incorporated herein by reference.
The term "min'1n as used herein, refers to units of inverse minutes,
The term "neutralized anionic surfactant" as used herein refers to any already neutralized anionic surfactant; i.e., this term includes both an anionic surfactant which has been provided in the pre-neutralized form, as well as an anionic surfactant which has been provided in the acid form and neutralized in a previous step of the process.
The term "RPM" as used herein refers to revolutions per minute.
In accordance with the present invention, it has been recognized that certain materials degrade when exposed to shear in the laundry detergent bar manufacturing process. Such a material is hereinafter described as a "shear-sensitive material." The present invention provides for a manufacturing process in which the shear rate and total shear are controlled, once the shear-sensitive material is added. It has been found that controlling the shear rate at the extrusion step is particularly important to prevent degradation of the shear-sensitive material.
This improved process provides many surprising advantages over the typical laundry detergent bar manufacturing process. For example, because degradation of the shear-sensitive material is significantly reduced, a lower amount of shear-sensitive material may be added to a laundry detergent bar formulation, while maintaining the same cleaning benefits. Because shear-sensitive materials are typically expensive, this improved process allows laundry detergent bars to be produced at a lower per>unit cost. The present invention also allows a wider variety of shear-sensitive materials to be incorporated into laundry detergent bars. This provides greater formulation flexibility, providing enhanced performance, and lowered per-unit costs, The improved process also results in bars containing the shear-sensitive materials with more consistent cleaning and physical properties, which possess acceptable storage stability, and deliver good in-use shear-sensitive material activity. Furthermore, for a laundry detergent bar, such good in-use shear-sensitive material activity permits consumers to actually expend less physical effort (i.e., reduced rubbing of clothes with the bar) to achieve acceptable laundering results.
Without intending to be limited by theory, it is believed that shear can cause a shear-sensitive material to degrade via a variety of mechanisms. For example, to perform its catalytic function, an enzyme typically requires a specific conformation. Shear may disrupt or deform this conformation, degrading (i.e. denaturing) the enzyme and reducing its catalytic activity when a consumer uses
the laundry detergent bar. The process of the current invention controls shear rate and total shear after an enzyme is added, and thereby maintains enzymatic activity.
Without intending to be limited by theory, it is believed that with certain other shear-sensitive materials, such as those contained within a particle, the rate and the amount of degradation may be directly proportional to the surface area of the particle. For example, an oxygen bleach, or a bleach activator contained within a particle may degrade when exposed to external moisture. Typically, in an intact particle, only the outer surface of the particle is exposed to moisture, and therefore, only the oxygen bleach on the surface of the particle will degrade. Thus, assuming an even distribution of oxygen bleach throughout the particle, the amount and rate of oxygen bleach degradation is directly proportional to the amount of surface area which is exposed to moisture. However, shear may cause a particle, such as that containing an oxygen bleach, to fragment. Fragmentation of the particle results in a greater surface area and a correspondingly greater exposure of the oxygen bleach to degrading moisture. This results in a more rapid and increased amount of oxygen bleach degradation. This degradation results in reduced cleaning benefits, as well as layering and puffing of the laundry detergent bar, Accordingly, the controlled shear rate and total shear of the present invention decreases such degradation by reducing particle fragmentation.
Without intending to be limited by theory it is also believed that shear can degrade a material by actually severing the material. For example, a wax aids bar processing by fluidizing the detergent paste, However, if too much shear is applied, then aesthetic and physical problems occur in the finished product. For example, the finished laundry detergent bar may take too long to harden, and may form undesirable layers,
Accordingly, the present invention solves such degradation problems by providing an improved process for the manufacture of a laundry detergent bar, The process described herein includes the steps of providing at least one detersive surfactant and at least one adjunct bar ingredient, and mixing the detersive surfactant and the adjunct bar ingredient to form a detergent premix. A shear-sensitive material is added to the detergent premix, and mixed to form a homogenized detergent composition. The homogenized detergent composition is then extruded under shear into the shape of a laundry detergent bar.
In the process of the present invention, at least one detersive surfactant is provided. The detersive surfactant may be in any physical form useful in a laundry detergent bar composition, such as a liquid, a paste, a flake, a noodle, etc. A preferred detersive surfactant is selected from the group consisting of a cationic surfactant, an anionic surfactant, a nonionic surfactant, an ampholytic surfactant, a zwitterionic surfactant, and mixtures thereof. Nonlimiting examples of detersive surfactants useful in the laundry detergent bar include, the conventional C11-C18 alkyl benzene sulfonates ("LAS") and primary, branched-chain and random C10-C20 alkyl sulfates ("AS"), the C10-C18
secondary (2,3) alkyl sulfates of the formula CH3CH2)x(CHOSO3'M+) CH3 and CH3 (CH2)y(CHOS03"M+) CH2CH3 where x and (y +1) are integers of at least
about 7, preferably at least about 9, and M is a water-solubilizing cation, especially sodium, unsaturated sulfates such as oleyl sulfate, the C10-C18alkyl alkoxy sulfates ("AEXS"; especially EO 1-7 ethoxy sulfates), C10-C18 alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarfaoxylates), the C10-C18 glycerol ethers, the C10-C20 alkyl polyglycosides and their corresponding sulfated polyglycosides, and C12-C20 alpha-sulfonated fatty acid esters.
If desired, the conventional nonionic and amphoteric surfactants such as the C12-C18 ethoxylates fAE") including the so-called narrow peaked alkyl ethoxylates and C6-C12 alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), C10-C18 amine oxides, and the like, can also be included in the overall compositions. The C10-C18 N-alkyl polyhydroxy fatty acid amides can also be used. Typical examples include the C12-C18N-methylglucamides. See WO
92706154--to Cook, et at., published April 16, 1992. Other sugar-derived surfactants include the N-alkoxy polyhydroxy fatty acid amides, such as
N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl glucamides can be used for low sudsing. C10-C20 conventional soaps may also be used. If high sudsing is desired, the branched-chain C10-C16soaps may be
used. Mixtures of anionic and nonionic surfactants are especially useful. Other conventional useful surfactants are listed in standard texts.
The detersive surfactant, and particularly an anionic surfactant, may be provided in either the pre-neutralized form, such as a neutralized anionic surfactant paste, and/or as the acid form of the surfactant, and neutralized in the process described herein. In a preferred embodiment, the acid form of the
surfactant is provided as the detersive surfactant, and is neutralized by the adjunct bar ingredient to form the detergent premix,
The total amount of detersive surfactant useful herein is from about 0,5% to about 60%, preferably from about 10% to about 50% and more preferably from about 15% to about 30% of the laundry detergent bar, by weight.
In addition to the detersive surfactant, at least one adjunct bar ingredient is provided. The adjunct bar ingredient may provide a wide variety of chemical, cleaning, and aesthetic benefits. For example, the adjunct bar ingredient may neutralize the acid form of the detersive surfactant, enhance cleaning performance, treat the substrate to be cleaned, and/or to modify the aesthetics of the laundry detergent bar. Non-limiting examples of the adjunct bar ingredient useful herein include a brightener, a builder, a clay soil removal/antiredeposition agent, a dye transfer inhibitor, an enzyme stabilizing system, a fabric softener, and mixtures thereof. The laundry detergent bar may also comprise other ingredients including a processing aid, a dye or pigment, a soil release agent, a dispersing agent, a suds suppressor, etc.
Bn'ghtening or whitening agents known in the art can be incorporated herein at levels typically from about 0.05% to about 1.2%, by weight of the laundry detergent bar. Commercial optical brighteners which may be useful in the present invention can be classified into subgroups, which include, but are not necessarily limited to, derivatives of stilbene, pyrazoline, coumarin, carboxylic acid, methinecyanines, dibenzothiphene-5,5-dioxide, azoles, 5- and 6-membered-ring heterocycles, and other miscellaneous agents. Examples of such brighteners are disclosed in 'The Production and Application of Fluorescent Brightening Agents", M. Zahradnik, Published by John Wiley & Sons, New York (1982)1 Anionic brighteners are preferred herein.
Builders can optionally be included in the compositions herein to assist in controlling mineral hardness and to assist in the removal of particulate soils. Inorganic as well as organic builders may be used. Inorganic or phosphate-containing detergent builders useful herein include, but are not limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphates (exemplified by the tripolyphosphates, pyrophosphates, and glassy polymeric meta-phosphates), phosphonates, phytic acid, silicates, carbonates (including bicarbonates and sesquicarbonates), sulphates, and aluminosilicates. However, non-phosphate builders are required in some locales. Importantly, the
compositions herein function surprisingly well even in the presence of the so-called "weak" builders (as compared with phosphates) such as citrate, or in the so-called "underbuilt" situation that may occur with zeolite or layered silicate builders.
The compositions of the present invention may also optionally contain water-soluble ethoxylated amines having clay soil removal and antiredeposition properties. The most preferred soil release and antiredeposition agent is ethoxylated tetraethylenepentamine. Exemplary ethoxylated amines are further described in U.S. Patent 4,597,898 to VanderMeer, issued July 1,1986. Another group of preferred clay soil removal-antiredeposition agents are the cationic compounds disclosed in European Patent Application 111,965, Oh and Gosselink, published June 27, 1984. Other clay soil removal/antiredeposition agents which can be used include the ethoxylated amine polymers disclosed in European Patent Application 111,984, Gosselink, published June 27, 1984; the zwitterionic polymers disclosed in European Patent Application 112,592, Gosselink, published July 4,1984; and the amine oxides disclosed in U.S. Patent 4,548,744, Connor, issued October 22, 1985. Other clay soil removal and/or antiredeposition agents known in the art may also be utilized in the compositions herein, Another type of preferred antiredeposition agent includes the carboxy methyl cellulose (CMC) materials. These materials are well known in the art.
The compositions of the present invention may also include one or more materials effective for inhibiting the transfer of dyes from one fabric to another during the cleaning process. Generally, such dye transfer inhibiting agents include polyvinyl pyrrolidone polymers, polyamine N-oxide polymers, copolymers of N-vinylpyrrolidone and N-vinylimidazole, manganese phthalocyanine, peroxidases, and mixtures thereof. If used, these agents typically comprise from
about 0:01% to about 10% by weight of the composition, preferably from about 0.01% to about 5%, and more preferably from about 0.05% to about 2%.
If an enzyme is present herein, then the adjunct bar ingredient of the present invention may include an enzyme stabilizing system, to reduce, for example, enzyme degradation caused by chemical reactions. Enzymes for use in detergents can be stabilized by various techniques. Enzyme stabilization techniques are disclosed and exemplified.in U.,S,.3,60O,319,.August 17, 1971, Gedge et al, EP 199,405 to. Venegas, issued June 24, 1992 and EP 200,586, to Valet, issued July 12, 1989. Enzyme stabilization systems are also described,
for example, in U.S. 3,519,570,A to McCarty, issued July 7, 1970 useful Bacillus, sp. AC13 giving proteases, xylanases and cellulases, is described in WO 94/01532 A to Bisgard-Frantzen, et at, published January 20, 1994. A preferred enzyme stabilizing system includes calcium ions, magnesium ions, boric acids, propylene glycols, short chain carboxylic acids, boronic acids, and mixtures thereof, and is designed to address different stabilization problems depending on the type and physical form of the enzyme.
Various through-the-wash fabric softeners, especially the impalpable smectite clays of U.S. Patent 4,062,647, Storm and Nlrschl, issued December 13,1977, as well as other softener clays known in the art, may optionally be used typically at levels of from about 0.5% to about 10% by weight in the present compositions to provide fabric softener benefits concurrently with fabric cleaning. Clay softeners can be used in combination with amine and cationic softeners as disclosed, for example, in U.S. Patent 4,375,416 to Crisp et al., March 1, 1983 and U.S. Patent 4,291,071 to Harris et al., issued September 22,1981.
The total amount of adjunct bar ingredient useful herein is from about 40% to about 99.5%, preferably from about 50% to about 90%, and more preferably from about 70% to about 85% of the laundry detergent bar, by weight.
The laundry detergent bars of the present invention may be processed in soap or detergent bar making equipment with some or all of the following key equipment: a moderate speed mixer, mill, extruder, logo stamp/cutter, cooling tunnel and wrapper. Accordingly, the detersive surfactant and the adjunct bar ingredient are provided and added to a mixer. The mixer then combines these ingredients to form a detergent premix. This mixing step may take place in, for example, in one or more moderate speed mixers.
The moderate speed mixer according to the present invention is a mixer having a rotatable central shaft, and typically, several radially-extending arms. As employed in the present invention, a "moderate speed mixer" is a mixer in which the central shaft rotates at a speed of less than about 750 RPM, preferably less than about 500 RPM, more preferably less than about 250 RPM, and even more preferably from about 30 to about 100 RPM, A preferred moderate speed mixer suitable for use herein is a Lodige KM "Ploughshare". The KM mixer has a rotatable central shaft and several arms extending from the central shaft with a triangular attachment on the end of the arms known as the "plow." Inside the mixer cavity are several smaller blades extending from the wall of the mixer
which can be rotated at high speeds. Of course, other moderate speed mixers may also be employed in the present invention and are available from a variety of sources including Schugi. Also useful herein are twin-screw mixers, commercially sold as Eirich, O'Brien and Drais mixers. The moderate speed mixer may be operated at a moderate shear rate, or at a low shear rate, as desired, by adjusting the shaft speed, the plow configuration, etc.
While the entire process herein may be completed in a single moderate speed mixer and extruded therefrom, it is preferred that the process of the present invention utilize at least two mixers and at least one extruder, with at least one of the mixers being a moderate speed mixer. In a preferred embodiment, the detergent premix is formed in a moderate speed mixer, and then transferred to a second moderate speed mixer, wherein the detergent premix is cooled and the shear-sensitive material is added. The shear-sensitive material is substantially evenly distributed throughout the homogenized detergent composition.
Certain detersive surfactants, notably anionic surfactants, require shear in order to properly structure the detergent premix. Accordingly, in a preferred embodiment of the present invention, the detersive surfactant and the adjunct bar ingredient are mixed under shear in a moderate speed. mixer to form the detergent premix. In a preferred embodiment of the invention, the detergent premix comprises a neutralized anionic surfactant. It is especially preferred that the acid form of an anionic surfactant is provided as the detersive surfactant, and is neutralized by the adjunct bar ingredient in a moderate speed mixer under shear to form the detergent premix, Without intending to be limited by theory, it is believed that a moderate speed mixer at this step insures both complete neutralization of the acid, and proper structuring of the detergent premix.
The forming of the detergent premix may involve many exothermic reactions, such as acid-base neutralization reactions, Furthermore, if formed under high shear, mechanical energy may transform into thermal energy, resulting in a batch temperature of 100 °C, or more. However, it has also been found that certain shear-sensitive materials may also be degraded by such high temperatures. For example, an oxygen bleach may degrade when added to a detergent premix whose temperature is greater than 70 °C.
To lower the temperature between the formation of the detergent premix and the adding of the shear-sensitive material, it is preferred that the process of
the invention further include a cooling step before the addition of the shear-sensitive material to the detergent premix. The cooling step may include, for example, an air cooling step whereby air is blown through the mixer, and/or a water cooling step whereby cool water is pumped through a water jacket placed around at least portion of the mixer. Another extrusion method circulates a coolant (e.g., liquid nitrogen, or cooled water) within a cooling jacket, or within the screw. However, if the detergent premix is cooled too much, then it becomes too thick to process effectively and efficiently. Therefore, it is preferred that the temperature of the detergent premix and the homogenized detergent composition in the adding step, in the homogenization step, and in the extrusion step remains between about 40 °C to about 80 °C, preferably between about 50 °C to about 70 oC, and more preferably between about 50 °C to about 60oC.
In the process of the present invention, at least one shear-sensitive material is provided, and then added to the detergent premix. The shear-sensitive material useful herein provides a benefit when included in a laundry detergent bar. However, when the shear-sensitive material is exposed to shear, and especially high shear rates and a high total shear, this benefit is reduced via degradation. A preferred shear-sensitive material for use herein includes an enzyme, a bleach, a bleach activator, a wax, and mixtures thereof. The shear-sensitive material may be composed of a single ingredient, or a plurality of ingredients; i.e., a bleach included within a particle, or an enzyme included within an enzyme prill.
Enzymes are normally incorporated into a laundry detergent bar at levels sufficient to provide a "cleaning-effective amount" The term "cleaning effective amount,' refers to any amount capable of producing a cleaning, stain removal, soil removal, whitening, deodorizing, or freshness-improving effect on substrates such as fabrics, and the like. Accordingly, a preferred enzyme useful herein includes a protease, an amylase, a lipase, a cellulase, a cutinase, a peroxidase, and mixtures thereof of any suitable origin, such as vegetable, animal, bacterial, fungal and yeast origin. Preferred selections are influenced by factors such as pH-activity and/or stability optima, thermostability, and stability to active detergents, builders and the like. In this respect bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases, and fungal cellulases.
Suitable examples of proteases are the subtilisins which are obtained from particular strains of B. subtilis and B. licheniformis. One suitable protease is
obtained from a strain of Bacillus, having maximum activity throughout the pH range of 8-12, developed and sold as ESPERASE® by Novo Industries A/S of Denmark, hereinafter "Novo". Other suitable proteases include ALCALASE® and SAVINASE® from Novo and MAXATASE® from International Bio-Synthetics, Inc., The Netherlands; as well as Protease A and Protease B as disclosed in EP 130,756 A to Bott, published January 9, 1985. See also a high pH protease from Bacillus sp. NCIMB 40338 described in WO 93/18140 A1 to Aaslyng et al,, published September 16, 1993. Enzymatic detergents comprising protease, one or more other enzymes, and a reversible protease inhibitor are described in to Hansen et al., published March 5,1992, Other preferred proteases include those of WO 95/10591 A1 to Baeck et al., published April 20, 1996. When desired, a protease having decreased adsorption and increased hydrolysis is available as described in WO 95/07791 A1 to Gerber, published March 23, 1995. A recombinant trypsin-like protease for detergents suitable herein is described in WO 94/25583 to Branner et al., published November 10, 1994, An especially preferred protease is described in U.S. Patent 5,679,630 to A. Baeck, et al, issued October 21, 1997, entitled "Protease-Containing Cleaning Compositions," and U.S. Patent 5,677,272 to C. Ghosh, et al, issued October 14, 1997, entitled "Bleaching Compositions Comprising Protease Enzymes."
Amylases suitable herein, especially for, but not limited to automatic dishwashing purposes, include, for example, -amylases described in GB 1,296,839 to Outtrup H, et al., published November 22, 1972 to Novo; RAPIDASE®, International Bio-Synthetics, Inc. and TERMAMYL®, Novo. FUNGAMYL® from Novo is especially useful. Engineering of enzymes for improved stability, e.g., oxidative stability, is known. See, for example J. Biol. Chem.-,.Vol. 260, No. 11, June 1985, pp. 6518-6521. Certain preferred embodiments of the present compositions can make use of amylases having improved stability in detergents such as automatic dishwashing types, especially improved oxidative stability as measured against a reference-point of TERMAMYL® in commercial use in 1993. These preferred amylases herein share the characteristic of being "stability-enhanced" amylases, characterized, at a minimum, by a measurable improvement in one or more of: oxidative stability, e.g., to hydrogen peroxide / tetraacetylethylenediamine in buffered solution at pH 9-10; thermal stability, e.g., at common wash temperatures such as about 60 °C; or alkaline stability, e,g,, at a pH from about 8 to about 11, measured versus the
above-identified reference-point amylase. Stability can be measured using any of the art-disclosed technical tests. See, for example, references disclosed in WO 94/02597 to Bisgard-Frantzen and Svendsen, published February 3, 1994. Stability-enhanced amylases can be obtained from Novo or from Genencor International. One class of highly preferred amylases herein have the commonality of being derived using site-directed mutagenesis from one or more of the Bacillus amylases, especially the Bacillus -amylases, regardless of whether one, two or multiple amylase strains are the immediate precursors, Oxidative stability-enhanced amylases vs. the above-identified reference amylase are preferred for use, especially in bleaching, more preferably oxygen bleaching, as distinct from chlorine bleaching, laundry detergent bars herein. Such preferred amylases include (a) an amylase according to the hereinbefore referenced WO 94/02597 to Bisgard-Frantzen and Svendsen, published February 3,1994, as further illustrated by a mutant in which substitution is made, using alanine or threonine, preferably threonine, of the methionine residue located in position 197 of the B, licheniformis alpha-amylase, known as TERMAMYL®, or the homologous position variation of a similar parent amylase, such as B. amyloliquefaciens, B. subtilis, or 8. stearothermophilus; (b) stability-enhanced amylases as described by Genencor International in a paper entitled "Oxidatively Resistant alpha-Amylases" presented at the 207th American Chemical Society National Meeting, March 13-17 1994, by C. Mitchinson; (c) particularly preferred amylases herein include amylase variants having additional modification in the immediate parent as described in WO 95/10603 A to Bisgard-Frantzen, et al,, published April 20, 1995 and are available from the assignee, Novo, as DURAMYL®. Other particularly preferred oxidative stability enhanced amylase include those described in WO 94/18314 to Antrim, et al., to Genencor International, published August 18, 1994 and WO 94/02597 to Bisgard-Frantzen and Svendsen, published February 3, 1994, to Novo. Any other oxidative stability-enhanced amylase can be used, for example as derived by site-directed mutagenesis from known chimeric, hybrid or simple mutant parent forms of available amylases. Other preferred enzyme modifications are accessible, See WO 95/09909 A to Borch, et al., published April 13,1995, to Novo.
Suitable lipase enzymes for detergent usage include those produced by microorganisms of the Pseudomonas group, such as Pseudomonas stutzeri ATCC 19.154, as disclosed in GB 1,372,034 to Dijk and Berg, published October
The bleach useful herein has a bleaching activity when used in a laundry detergent bar, and includes an oxygen bleach, a reducing bleach, a chlorine bleach, a photobleach, and mixtures thereof. Preferably, the bleach is in a solid, particulate, form. Moreover, it is preferred that the bleach particle be highly soluble in water. The oxygen bleach can include, for example, a peroxygen compound, a peracid, an enzymatic source of hydrogen peroxide, and mixtures thereof. A hypohalite such as a chlorine bleach like hypochlorite, may also be used. When present, the laundry detergent bar will contain the bleach at levels of from about 1% to about 30%, more typically from about 5% to about 20%, by weight of the final composition.
Preferably, an oxygen bleach will be used herein. Common oxygen bleaches of the peroxygen type include hydrogen peroxide, inorganic peroxides, superoxides, organic hydroperoxides, inorganic peroxohydrates, organic peroxohydrates, inorganic peroxoacids, and the organic peroxyacids, including hydrophilic and hydrophobic mono- or di- peroxyacids. These can be peroxycarboxylic acids, peroxyimidic acids, amidoperoxycarboxylic acids, or their salts including the calcium, magnesium, or mixed-cation salts. Peracids of various Kinds can be used both in free form and as precursors known as "bleach activators" which, when combined with a source of hydrogen peroxide, perhydrolyze to release the corresponding peracid. Preferred oxygen bleaches include OXONE™ by DuPont, CUROX™ from Akzo or CAROAT™ from Degussa, percarbonate, perborate, and mixtures thereof.
Mixed oxygen bleach systems are generally useful, as are mixtures of any oxygen bleaches with the known bleach activators, organic catalysts, enzymatic catalysts- and mixtures thereof; moreover such mixtures may further include bnghteners, photobleaches and dye transfer inhibitors of types well-known in the art.
Examples of an oxygen bleach useful herein includes, for example, dry particles having an average particle size in the range from about 500 micrometers to about 1,000 micrometers, not more than about 10% by weight of said particles being smaller than about 200 micrometers and not more than about 10% by weight of said particles being larger than about 1,250 micrometers, Percarbonates and perborates are widely available in commerce, for example from FMC, Solvay and Tokai Denka.
30, 1974. See also lipases in Japanese Patent Application 53,20487 to Inugai, published February 24, 1978. This lipase is available from Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name LIPASE P "AMANO," or "AMANO-P." Other suitable commercial lipases include Amano-CES, lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var. lipolyticum NRRLB 3673 from Toyo Jozo Co., Tagata, Japan; Chromobacter viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands, and lipases ex Pseudomonas gladioli. LIPOLASE® enzyme derived from Humicola lanuginosa and its variants are commercially available from Novo. See also EP 341,947 to Cornelissen, et al., issued August 31, 1994. Lipase and amylase variants stabilized against peroxidase enzymes are described in WO 94/14951 to Halkier, et al., published July 7, 1994 A to Novo. See also WO 92705249 to Clausen, et al., published April 2,1992 and .
Cellulases usable herein include both bacterial and fungal types, preferably having a pH optimum between 5 and 9.5. U.S. 4,435,307, Barbesgoard et al, March 6, 1984, discloses suitable fungal cellulases from Humicola insolens or Humicola strain DSM1800 or a cellulase 212-producing fungus belonging to the genus Aeromonas, and cellulase extracted from the hepatopancreas of a marine mollusk, Dolabelia Auricula Solander. Suitable cellulases are also disclosed in 68-8-2.075.028 to Barbesgaar, et al., issued March 28, 1984; GB-B-2.095.275 to Murata, et al,, issued August 7, 1985 and DE-OS-2.247.832 to Horikoshi and Ikeda, issued June 27,1974. CAREZYME® and CELLUZYME® (Novo) are especially useful. See also WO 91/17243 to Hagen, et al., published November 14,1991 as to Novo.
Cutinase enzymes suitable for use herein are described in WO 88/09367A to Kolattukudy, et al,, published December 1,1988 to Genencor.
Peroxidase enzymes may be used in combination with oxygen sources, e.g., percarbonate, perborate, hydrogen peroxide, etc,, for "solution bleaching" or prevention of transfer of dyes or pigments removed from substrates during the wash to other substrates present in the wash solution. Known peroxidases indude horseradish peroxidase, ligninase, and haloperoxidases such as chloro-or bromo-peroxidase. Peroxidase-containing detergent compositions are disclosed in , October 19, 1989 to Novo and WO 89/09813 A to Damhus, et al., published October 19,1989 to Novo.
A photobleach may also be used herein. A preferred photobleach includes the sulfonated zinc and/or aluminum phthalocyanines, See U.S. Patent 4,033,718, issued July 5, 1977 to Holcombe et al. If used, detergent compositions will typically contain from about 0.025% to about 1.25%, by weight, of such bleaches, especially sulfonate zinc phthalocyanine.
The shear-sensitive material may also comprise a bleach activator, either alone, or in conjunction with a bleach, If present, the amount of bleach activator will typically be from about 0.1% to about 60%, more typically from about 0.5% to about 40% of the bleaching composition comprising the bleaching agent-plus-bleach activator.
A preferred bleach activator useful herein includes amides, imides, esters and anhydrides. Commonly at least one substituted or unsubstituted acyl moiety is present, covalently connected to a leaving group as in the structure R-C(0)-L, wherein L denotes a leaving group. With respect to the above bleach activator structure, the atom in the leaving group connecting to the peracid-forming acyl moiety R-(C)0- is most typically 0 or N. Bleach activators can have non-charged, positively or negatively charged peracid-forming moieties and/or non-charged, positively or negatively charged leaving groups. One or more peracid-forming moieties or leaving-groups may be present See, for example, U.S, 5,595,967 to Kellett, et al., issued January 21,1997, U.S. 5,561,235 to Bums, et al., issued October 1, 1996, U.S. 5,560,862 to Burns, et al., issued October 1, 1996 or the bis-(peroxy-carbonic) system of U.S, 5,534,179 to Kellett, et al,, issued July 9,1996. Bleach activators can be substituted with electron-donating or electron-releasing moieties either in the leaving-group or in the peracid-forming moiety or moieties, changing their reactivity and making them more or
less suited to particular pH or wash conditions. For example, electron-withdrawing groups such as N02 improve the efficacy of bleach activators
intended for use in mild-pH (e.g., from about 7.5- to about 9.5) wash conditions. In one preferred mode of use, bleach activators are combined with a source of hydrogen peroxide, such as the perborates or percarbonates, in a single product. Conveniently, the single product leads to in situ production in aqueous solution (i.e., during the washing process) of the percarboxylic acid corresponding to the bleach activator,
Of the above classes of bleach precursors, preferred classes include the esters, including acyl phenol sulfonates, acyl alkyl phenol sulfonates or acyl
oxybenzenesulfonates (OBS leaving-group); the acyl-amides; and the quaternary ammonium substituted peroxyacid precursors including the cationic nitriles. Preferred hydrophobia bleach activators include sodium nonanoyloxybenzene sulfonate (NOBS or SNOBS), substituted amide types described in detail hereinafter, such as activators related to NAPAA, and activators related to certain imidoperacid bleaches, for example as described in U.S. Patent 5,061,807 to Gethoffer, et al,, issued October 29, 1991 and assigned to Hoechst Aktiengesellschaft of Frankfurt, Germany. Japanese Laid-Open Patent Application (Kokai) No. 4-28799 to Yamada, et al., published January 31, 1992 for example describes a bleaching agent and a bleaching detergent composition comprising an organic peracid precursor described by a general formula and illustrated by compounds which may be summarized more particularly as conforming to the formula:
wherein L is sodium p-phenolsulfonate, R1 is CH3 or C12H25 and R2 is H. Analogs of these compounds having any of the leaving-groups identified herein and/or having R1 being linear or branched C6-C16 are also useful.
A wax may also be included herein as a shear-sensitive material. A wax is included In a laundry detergent bar to ease processing and to provide structuring and binding benefits. A wax can further act as an emulsifier and suds booster, by complexing with the surfactant. The wax useful herein is an animal wax, a mineral wax, a petroleum wax, and a synthetic wax. A preferred wax useful herein includes coconut monoethylene amide, beeswax, shellac wax, ozocerite, ceresin, montan, ethylenic polymers, a paraffin wax, a camauba wax, and mixtures thereof.
The detergent premix and the shear-sensitive material is then mixed,
preferably under shear, to form a homogenized detergent composition, and
extruded under shear into the shape of a laundry detergent bar. Shear results
/from the interaction of many factors in a laundry detergent bar manufacturing
process. For example, factors which influence shear include; the mixer itself, the screw which transports the detergent paste to the extruder, the clearances between the screw and the barrel which surrounds it, the viscosity of the detergent paste, and the shape and width of the extrusion die. While relatively high shear may be desirable at some steps, e.g., to mix the surfactant and the adjunct ingredient, once the shear-sensitive material is added, the shear rate and total shear must be controlled so as to minimize degradation of the shear-sensitive material,
The shear rate and total shear may be controlled by many means. This may be achieved, for example, by transferring the detergent premix to another mixer which has different shear characteristics, by strictly controlling the mixer speed, by controlling the screw speed during extrusion, by increasing the size of the hole(s) in the extrusion die, by using 'constant pitch screws, and/or by decreasing the pressure drop across the extrusion die. For example, the pressure drop across the extrusion die may be adjusted by changing the length of the extrusion die, or by adjusting the size/shape of the extrusion die. In the present invention, the shear rate in the extruding step is from about 1 to about 1000 min-1, and the total shear in the homogenization step and the extruding step is from about 300 to about 5000. It is preferred that the shear rate and total shear are controlled by transferring the detergent premix into a moderate speed mixer, as described hereinbefore.
The shear rate is defined (using the two-plate shear concept) as the speed differential between adjacent flow layers/plates. The shear rate equals the change in velocity of the flow layer (measured in m/min) divided by the distance between, the plates (measured in m), Therefore, the shear rate, in units of min'1, can be calculated for any specific step. Total shear is calculated by multiplying the shlar rate by the residence time at that shear. Accordingly, total shear is unit less,
The shear-sensitive material must be mixed with the detergent premix in a homogenization step, to form a homogenized detergent composition, In a process described herein, the homogenization step takes place in a mixer, and the homogenized detergent composition is dumped into an extruder for the extruding step, In an alternate embodiment, such as where multiple extruders are used in series, the homogenization step to form the homogenized detergent composition takes place within the extruder, immediately prior to the extruding
step. In either of the above processes, the typical amount of time spent to homogenizing the shear-sensitive material and detergent premix into a laundry detergent composition is negligible compared to the time spent extruding the laundry detergent composition into the form of a bar. Furthermore, the typical shear rate at homogenization is low or minimal, as compared to the shear rate during extrusion.
The extruding step, as described herein, includes all aspects of, for example, preliminary plodding, refining plodding, and final plodding. Each extruder includes a variety of shear factors which contribute to the shear rate and the total shear, for example, the outerbarrel shear factor, the innerbarrel shear factor and the screwflights shear factor. The shear rate for the various shear factors at the extruding step can be calculated according to the following formulas
shear rate for each shear factor volumetric flowrate, in m3/min extruder worm depth, in m extruder worm diameter, in m worm pitch distance/length, in m pitch angle relative to vertical worm speed, in RPM number of worm flights.
The shear rate for each shear factor, during extrusion is from about 1 to about 1000 min-1, preferably from about 2 to about 700 min-1, more preferably from about 4 to about 400 min-1.
The total amount of shear present from the time that the shear-sensitive material is added can be calculated by adding the shear present during the homogenizing step and the shear present during the extruding step. However, as previously noted, the shear present at the homogenization step is typically negligible as compared to that present at the extrusion step. Furthermore, it has been found that the total shear at the extrusion step plays a significantly greater role in providing improved bar physical properties and preventing the degradation of the shear-sensitive material. Accordingly, in addition to the shear rate at extrusion, the total shear at the extrusion step must be controlled.
The total shear at the extrusion step can be calculated according to the following formula:
5 = shear rate
T = total shear
t = residence time, in min.
The shear for each extruder, which takes into account residence time of the material during the extrusion step, is preferably from about 10 to about 2000, more preferably from about 100 to about 700 and more preferably from about 200 to about 500 per extruder. As there are typically from about 1 to about 4 extruders, the total shear for the extrusion step is therefore from 300 to 5000, preferably from 500 to 2100 and more preferably from 700 to 1500.
As the homogenized detergent composition is forced through the extrusion' die, it experiences a pressure drop, from one side of the die, to the other, It has been found that the pressure drop across the extrusion die, and its relationship to the viscosity of the material, also significantly influences the shear rate and the total shear. The pressure drop, P, can be calculated according to the following formula:
where Q = volumetric flowrate through the die, in m3/min
P = pressure drop through the die k = die (or drilled plate) constant, in m3 µ, = viscosity of the material,
For round dies, this equation becomes:
For irregular-shaped dies, the proper equation is:
die cross-sectional area, in m2
total wetted periphery, in m
land or length of orifice parallel to material flow, in m
radius of round die, in m.
It is preferred that the laundry detergent composition herein is extruded through an extrusion die, where the pressure dropA/iscosity ratio (P/µ) across the extrusion die is less than about 4 X 1013/min, preferably less than 1 x 1013/min. If more than one extrusion die is used in the process described herein, then it is preferred that the pressure drop/viscosity ratio (P/µ) across the final extrusion die is less than about 4 X 1013/min, preferably less than 1 x 1013/min. The viscosity is measured at the temperature of the homogenized detergent composition during the actual extrusion step.
The homogenized detergent composition is then extruded under shear into the shape of a bar. The extruder useful herein has a barrel containing at least one extruding screw. The extruding screw rotates in order to force the homogenized detergent composition through an extrusion die. .The extruder may contain a single extruder screw, or multiple extruder screws having either a uniform or variable extruder screw diameter, The multiple extruder screws may
be either counter-rotating or co-rotating. Each extruder screw has one or more flights which spiral the length of the extrusion screw, The flight(s) may have either a constant pitch or a variable pitch, with the flights being either variable or uniform in flight depth.
Such extruders are also described as "plodders" and are available, for example, from Mazzoni (Busto Arsizio, Italy); Binacchi (Gazzada Schiano, Italy), APV-Baker (Peterborough, United Kingdom), and Warner & Pfleiderer (Stuttgart, Germany). The extruders useful herein include those commonly described as preliminary plodders, refining plodders, and final plodders. A preferred extruder is a duplex vacuum plodder with tangential twin screws of uniform diameters ranging from 150 mm to 350 mm, an extruding screw length to extruding screw diameter ratio of about 1:5 to about 1:8, and constant flight pitch lengths of about 70 mm to about 300 mm.
The shear rate during extrusion may be controlled by, for example, adjusting the viscosity of the homogenized detergent composition, using a refining plodder having large plate holes (e.g., greater than 1 cm in diameter), using an extruder screw having a constant screw pitch, heating or cooling the homogenized detergent composition, increasing the pitch length, reducing flow rate, and heating or cooling a portion of the extruder (e.g., the extrusion die). The total shear during extrusion may be controlled by, for example, adjusting the shear rate during extrusion, adjusting the residence time of the homogenized detergent composition, or adjusting the number of extruders.
To reduce air pockets within the formed bar, the extruding step is typically conducted under vacuum, Typically, the homogenized detergent composition will be conveyed to a double vacuum plodder, operating at high vacuum, e.g. 400 to 740 mm of mercury vacuum, so that entrapped air is removed. In addition to removing air pockets, extruders may also serve to form the finished laundry detergent bar's desired shape and desired aesthetics. For example, the extruder reduces cracking and affects the look, shape, surface feel, and smoothness of the finished product.
After extrusion as described above, the laundry detergent bar is typically stamped with the product brand name, and cut to the desired bar length, with conventional stamping and cutting equipment. The laundry detergent bar is usually cooled, for example in a cooling tunnel, before it is wrapped, packed into cases, and sent to storage, Cooling tunnels, wrappers, and packing machinery
are well known in the art. The laundry detergent bar is typically stored for at least 24 hours to age and harden the bar, before it is shipped and sold.
Laundry detergent bars manufactured by the process described herein have acceptable physical properties, including reduced layering caused by air pockets in the bar. While laundry detergent bars may contain air pockets from, for example, air trapped therein during the mixing stage, these air pockets are typically removed by plodding and/or extruding the laundry detergent bar under vacuum, However, such a vacuum does not remove the air pockets formed by chemical reactions which occur after extrusion. For example, when an oxygen bleach degrades in the extruded laundry detergent bar, it forms oxygen gas, which gather into air pockets, or rise to the'surface to give the bar a "puffed" appearance upon storage. The air pockets appear as layers throughout the bar. These layers may also weaken the bar integrity. However, because the process described herein reduces oxygen bleach degradation, this process significantly reduces such post-extrusion air pocket formation and layering. Accordingly, the process described herein produces laundry detergent bars which possess improved bar integrity. Laundry detergent bar integrity includes factors such as hardness, the rate of drying, etc.
The laundry detergent bars of the present invention possess acceptable hardness. A preferred method to measure hardness is to measure the penetration of a needle through the laundry detergent bar surface under a standard weight, for 5 seconds using a cone penetrometer. One such penetrometer Is made by Associated Instrument Manufacturers India Pvt. Ltd. (Model number AIM 512), The weight of the rod and the cone is 149 grams and an additional 50 gram weight is placed on the cone. The penetration reading of a fresh bar made as per the present invention will typically be about 20-30 (1/10 mm) and after 40 minutes it would be around 15-20 (1/10 mm). Laundry detergent bars aged about 3 days at ambient conditions will typically have a bar penetration reading of about 5-12 (1/10 mm).
Yet another physical property of consumer relevance is the rate of drying of the bar after usage and storage under high humidity conditions. A preferred method to measure this property is to place a bar with dimensions of 75 mm x 55 mm with one of its large flat surface in contact with about 20 ml of water in a petri
dish for 2 hours and then scraping the gel formed. This procedure is repeated for a second cycle except that the gel is not scraped off from the bar surface after the second contact with water. The bar is then stored under 30 degrees C and 88% Relative Humidity for 24 hours and then the bar surface which was exposed to the water is graded for dryness on a 1-5 grading scale by experienced operators as illustrated below:
Dryness Grade Physical state of the bar surface
1 very wet, very soft, melting, soft core
2 wet, soft gel, hard core
3 somewhat dry (moist), feels soft
4 somewhat dry (moist), feels hard
5 completely dry, hard
For good consumer acceptance, the dryness grade is typically between 3.5-5.0. Preferred bars of the present invention have a dryness grade within this range.
Examples of the invention are set forth hereinafter by way of illustration and are not intended to be in any way limiting of the invention.
The acid form of LAS is provided as a detersive surfactant. Excess STPP and excess sodium carbonate are provided as an adjunct bar ingredient, and mixed for about 12 minutes to form a detergent premix containing a neutralized anionic surfactant. The detergent premix is then cooled, via air cooling, to a temperature of about 55 °C, and sodium perborate is added as a shear-sensitive material. The detergent premix and the sodium perborate are mixed under shear in extruder 1, to form a homogenized detergent composition. The homogenized detergent composition is transferred to extruder 2, and then extruder 3, and finally extruded, into the shape of a laundry detergent bar, from extruder 3, The homogenized detergent composition is formed virtually instantaneously upon adding the shear-sensitive material to extruder 1.
Extrusion of the homogenized detergent composition is conducted under shear using three extruders, specifically, under a shear rate and residence time for each extruder at:
The extruded laundry detergent bar is then sent to storage. After 24 hours, no puffing is observed. After 5 days, no layering is observed. These bars possess acceptable oxygen bleach activity.
A laundry detergent bar is manufactured according to the process as described in Example 1, except as noted. Pre-neutralized coconut fatty alkyl sulfate paste is added to and mixed with the detergent premix in a mixer where the shaft speed is about 90 RPM. The detergent premix is then cooled by transferring it onto a moderate speed mixer, specifically, a KM mixer by Lodige, where further mixing and structuring takes place at a shaft speed of about 30 RPM. The shear-sensitive material (particulate sodium perborate and an enzyme prill) is added to the detergent premix, and dumped into an extruder, where it is formed into the homogenized detergent composition.
The extrusion step is conducted in a single extruder, under a shear rate of about 300 min-1, with a total residence time of about 12 minutes. The extruding of the homogenized detergent composition is conducted under both vacuum and shear. Specifically, the extruder uses a constant pitch screw and extrusion holes having a diameter of 1 cm. Accordingly, the total shear of the homogenization step and the extruding step is about 3600.
The bars made by the above process possess acceptable physical properties, no bar layering, and no bar puffing after 5 days. These bars possess acceptable enzyme and oxygen bleach activity,
A laundry detergent bar is manufactured according to the process as described in Example 1, except as noted. The detergent premix and the shear-sensitive material (a wax) are added to a moderate speed mixer set to a shaft speed of about 60 RPM, and a temperature of about 50 oC. The moderate speed mixer forms the homogenized detergent composition and dumps it into the series of three extruders.
Furthermore, the pressure drop/viscosity ratio across the extrusion die of extruder 3 is about 1 X 1013/min. The extruded laundry detergent bar is then sent to storage. After 24 hours, these bars are of an acceptable hardness, and no puffing is observed. After 5 days, no layering is observed.
A process for the manufacture of a laundry detergent bar comprising the steps of:
A. providing at least one detersive surfactant, such as herein described and one
or more adjunct bar ingredient such as herein described;
B. mixing the detersive surfactant and the adjunct bar ingredient to form a
detergent premix; characterised by
C. adding a shear-sensitive material being selected from bleaches, enzymes and combinations thereof to the detergent premix;
D. mixing the detergent premix and the shear-sensitive material to form a homogenized detergent composition; and
E. extruding the homogenized detergent composition under shear into the shape of a laundry detergent bar or
optionally extruding the homogenised composition through an extrusion die,
wherein the pressure drop/viscosity ratio across the extrusion die is less than about 4 X 1013/min,
having the shear rate in the extruding step from about 1 to 1000 min" , the total shear in the extruding step from about 300 to about 5000.
2. The process as claimed in claim 1, wherein the temperature of the detergent premix
and the homogenized detergent composition in the adding step, in the homogenization step,
and in the extruding step remains between 40°C to 80°C.
3. The process as claimed in claim 1 wherein the mixing step to form a detergent
premix is conducted under shear in a moderate speed mixer.
4. The process as claimed in any of the preceding claims, wherein the detergent premix
comprises a neutralized anionic surfactant.
5. A process for the manufacture of a laundry detergent bar substantially as herein
before described in any of the Examples.
|Indian Patent Application Number||995/DEL/1999|
|PG Journal Number||13/2008|
|Date of Filing||20-Jul-1999|
|Name of Patentee||THE PROCTER & GAMBLE COMPANY|
|Applicant Address||ONE PROCTER & GAMBLE PLAZA, CINCINNATI, STATE OF OHIO, UNITED STATES OF AMERICA.|
|PCT International Classification Number||C11D 9/00|
|PCT International Application Number||N/A|
|PCT International Filing date|