|1.||A detergent composition, comprising: (a) at least 1% by weight of a secondary (2,3) alkyl sulfate surfactant; (b) at least 0.05% by weight of calcium ions; (c) optionally, a detersiveactive amount of a detersive adjunct material, or mixtures thereof; (d) optionally, at least 0.05% by weight of magnesium ions; and (e) optionally, a fluid carrier.|
|2.||A composition according to Claim 1, wherein said detersive adjunct material (c) is a detersive surfactant which is a member selected from the group consisting of amine oxide surfactants, polyhydroxy fatty acid amide surfactants, sulfated polyhydroxy fatty acid amide surfactants, betaine surfactants, sultaine surfactants, alkyl ethoxy carboxylate surfactants, alkyl ethoxy sulfate surfactants and mixtures thereof.|
|3.||A composition according to either of Claims 1 or 2, wherein said detersive adjunct material (c) is a polycarboxylate builder.|
|4.||A composition according to Claim 3, wherein the builder is a citrate or oxydisuccinate builder.|
|5.||A clear liquid or gel composition according to any of Claims 14.|
|6.||A colorless composition according to any of Claims 15.|
|7.||A bar or granular composition according to any of Claims 14.|
|8.||Use of a secondary (2,3) alkyl sulfate surfactant in a stable detergent composition containing at least 0.05% by weight of calcium ions.|
FIELD OF THE INVENTION
The present invention relates to cleaning compositions and methods which employ secondary (2,3) alkyl sulfate surfactants and a source of calcium ions to enhance the removal of greasy, oily stains and soils from substrates. BACKGROUND OF THE INVENTION
Most conventional detergent compositions contain mixtures of various detersive surfactants in order to remove a wide variety of soils and stains from surfaces. For example, various anionic surfactants, especially the alkyl benzene sulfonates, are useful for removing particulate soils, and various nonionic surfactants, such as the alkyl ethoxylates and alkylphenol ethoxylates, are useful for removing greasy soils.
While a review of the literature would seem to suggest that a wide selection of anionic surfactants is available to the detergent manufacturer, the reality is that many such materials are specialty chemicals which are not suitable for routine use in low unit cost items such as home laundering compositions. The fact remains that many home-use laundry detergents still comprise one or more of the conventional alkyl benzene sulfonate or primary alkyl sulfate surfactants.
One class of surfactants which has found limited use in various compositions where emulsification is desired comprises the secondary alkyl sulfates. The conventional secondary alkyl sulfates are available as generally pasty, random mixtures of sulfated linear and/or partially branched alkanes. Such materials have not come into widespread use in laundry detergents, since they offer no particular advantages over the alkyl benzene sulfonates.
It has now been discovered that a particular sub-set of the class of secondary alkyl sulfates, referred to herein as secondary (2,3) alkyl sulfates ("SAS"), offers considerable advantages to the formulator and user of detergent compositions. For example, the secondary alkyl (2,3) sulfates are more soluble in aqueous media than their counterpart primary alkyl sulfates of comparable
chain lengths. Accordingly, they can be formulated as stable, homogeneous liquid detergents. In addition, the solubility of the secondary (2,3) alkyl sulfates allows them to be formulated in the concentrated form now coming into vogue with both granular and liquid laundry detergents. They are milder to skin in, for example, hand dishwashing operations. Moreover, the secondary (2,3) alkyl sulfates as used herein appear to exhibit good compatibility with detersive enzymes. Thus, in addition to compatibility with enzymes, the secondary (2,3) alkyl sulfates are exceptionally easy to formulate as heavy-duty liquid laundry detergents.
In addition to the foregoing advantages seen for the secondary (2,3) alkyl sulfates, it has now been determined that they are both aerobically and anaerobically degradable, which assists in their disposal in the environment.
Of course, the manufacturer of full -formulated detergent compositions is concerned not only with the safety, ease-of- handling and performance of the individual components of such compositions, but also with their compatibility with each other. For example, it has been discovered that the presence of calcium ions in a properly formulated detergent composition can assist in the removal of greasy/oily stains and soils. This is particularly true for hand dishwashing compositions. However, calcium can cause instability problems when used with detersive surfactants, which tend to precipitate or phase separate in liquid compositions in the presence of calcium ions. This is problematic under circumstances where liquid compositions are being formulated, and is intolerable where homogeneous clear and/or colorless liquids or gels are desired. By the present invention it has been determined that the secondary (2,3) alkyl sulfates tend to negatively interact less with calcium ions than do the conventional primary alkyl sulfates. The overall result is that more stable compositions, especially liquids and gels, with higher overall grease/oil cleaning performance can now be secured.
BACKGROUND ART The problems associated with the formulation of stable liquid detergent compositions and means to enhance stability are
described in various patents. See, for example: U.S. 3,998,750, Payne, as well as U.S. 4,435,317, Gerritsen, and U.S. 4,671,894, Lamb.
Detergent compositions with various "secondary" and branched alkyl sulfates are disclosed in various patents; see: U.S. 2,900,346, Fowkes et al, August 18, 1959; U.S. 3,468,805, Grifo et al, September 23, 1969; U.S. 3,480,556, De itt et al, November 25, 1969; U.S. 3,681,424, Bloch et al, August 1, 1972; U.S. 4,052,342, Fernley et al, October 4, 1977; U.S. 4,079,020, Mills et al , March 14, 1978; U.S. 4,235,752, Rossall et al , November 25, 1980; U.S. 4,529,541, Wilms et al , July 16, 1985; U.S. 4,614,612, Reilly et al, September 30, 1986; U.S. 4,880,569, Leng et al , November 14, 1989; U.S. 5,075,041, Lutz, December 24, 1991; U.K. 818,367, Bataafsche Petroleum, August 12, 1959; U.K. 1,585,030, Shell, February 18, 1981; GB 2,179,054A, Leng et al , February 25, 1987 (referring to GB 2,155,031). U.S. Patent 3,234,258, Morris, February 8, 1966, relates to the sulfation of alpha olefins using H2SO4, an olefin reactant and a low boiling, nonionic, organic crystallization medium. SUMMARY OF THE INVENTION
The present invention relates to the use of a secondary (2,3) alkyl sulfate surfactant in a stable, homogeneous liquid or gel detergent compositions, or in bar or granular compositions, containing a source of calcium ions which enhances cleaning performance, especially against greasy and oily soils and stains. The invention herein provides preferably liquid and gel, but also granular and bar, detergent compositions, comprising:
(a) at least about 1%, preferably at least about 2%, typically from about 3% to about 30% by weight of a secondary (2,3) alkyl sulfate surfactant;
(b) at least about 0.05% by weight of calcium ions;
(c) optionally, a detersive-active amount of a detersive adjunct material, or mixtures thereof;
(d) optionally, at least about 0.1% by weight of magnesium ions; and
(e) optionally, a fluid carrier.
Weight ratios of calcium cations anionic surfactant herein are typically near about stoichiometric, and are conveniently in the range from about 1:16 to about 1:30. Higher ratios are useful, but may negatively impact the for ulatability of liquid and gel products. Lower ratios, say, in the range of 1:300, still provide benefits in overall product performance.
In one embodiment that is particularly useful for dishwashing and fabric laundering, the compositions contain one or more detersive adjunct materials (c) which are detersive surfactants comprising a member selected from the group consisting of amine oxide surfactants, polyhydroxy fatty acid amide surfactants, sulfated polyhydroxy fatty acid amide surfactants, betaine surfactants, sultaine surfactants, alkyl ethoxy carboxylate surfactants, alkyl ethoxy sulfate surfactants, alkyl ethoxylate surfactants, alkyl polyglycoside surfactants, and mixtures thereof.
In another embodiment, the invention comprises compositions wherein said detersive adjunct material (c) is a polycarboxylate builder, especially a citrate or oxydisuccinate builder. Such compositions are especially useful as laundry detergents.
Low-sudsing compositions which additionally comprise a suds-control agent are also provided herein. High-sudsing compo¬ sitions which are substantially free of primary C14 and higher fatty acids are also provided. In yet another embodiment, clear liquid or gel compositions and/or colorless compositions are provided. The C1--C20 secondary (2,3) alkyl sulfates can conveni¬ ently be employed herein. The C1 -C18 compounds are preferred for laundry cleaning operations. The C12-C16 compounds are preferred for dishwashing compositions. The invention herein also encompasses a method for cleaning soiled surfaces, especially dishes but including fabrics, comprising contacting said surfaces with an aqueous medium containing an effective amount (typically, at least about 0.01%, preferably at least about 0.05%) of the compositions of this invention, under conditions of agitation. Such cleaning can be carried out in an automatic cleaning apparatus, or by hand, both with and without a presoak.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. All documents cited are incorporated herein by reference.
DETAILED DESCRIPTION OF THE INVENTION Primary Ingredients
Secondary (2.3) Alkyl Sulfate Surfactants - For the conveni¬ ence of the for ulator, the following identifies and illustrates the differences between the sulfated surfactants employed herein and otherwise conventional alkyl sulfate surfactants. Conventional primary alkyl sulfate surfactants have the general formula
ROSO3-M+ wherein R is typically a linear C10-C20 hydrocarbyl group and M is a water-solubilizing cation. Branched-chain primary alkyl sulfate surfactants (i.e., branched-chain "PAS") having 10-20 carbon atoms are also known; see, for example, European Patent Application 439,316, Smith et al, filed 21.01.91.
Conventional secondary alkyl sulfate surfactants are those materials which have the sulfate moiety distributed randomly along the hydrocarbyl "backbone" of the molecule. Such materials may be depicted by the structure
CH3(CH2)n(CH0S03-M+)(CH 2 ) m CH3 wherein m and n are integers of 2 or greater and the sum of m + n is typically about 9 to 15, and M is a water-solubilizing cation. By contrast with the above, the selected secondary (2,3) alkyl sulfate surfactants used herein comprise structures of formulas A and B
(A) CH3(CH2)χ(CH0S03"M + ) CH3 and
(B) CH3(CH2)y(CH0S03-M+) CH2CH3 for the 2-sulfate and 3-sulfate, respectively. Mixtures of the 2- and 3-sulfate can be used herein. In formulas A and B, x and (y+1) are, respectively, integers of at least about 6, and can range from about 7 to about 20, preferably about 10 to about 16. M is a cation, such as an alkali metal, ammonium, alkanolammonium, alkaline earth metal, or the like. Sodium is typical for use as M to prepare the water-soluble (2,3) alkyl sulfates, but ethanola - monium, diethanolammonium, triethanolammonium, potassium, ammonium, and the like, can also be used.
By the present invention it has been determined that the physical/chemical properties of the foregoing types of alkyl sulfate surfactants are unexpectedly different, one from another, in several aspects which are important to for ulators of various types of detergent compositions. For example, the primary alkyl sulfates can disadvantageously interact with, and even be precipi¬ tated by, metal cations such as calcium and magnesium. Thus, water hardness can negatively affect the primary alkyl sulfates to a greater extent than the secondary (2,3) alkyl sulfates herein. Accordingly, the secondary (2,3) alkyl sulfates have now been found to be preferred for use in the presence of calcium ions and under conditions of high water hardness, or in so-called "under-built" situations which can occur with nonphosphate builders. Importantly, when formulating concentrated liquid detergents with calcium or magnesium ions to enhance grease cutting or sudsing performance it has now been found that the primary alkyl sulfates can be problematic due to such interactions with calcium or magnesium cations. Moreover, the solubility of the primary alkyl sulfates is not as great as the secondary (2,3) alkyl sulfates. Hence, the formulation of high-active liquid and gel detergents has now been found to be simpler and more effective with the secondary (2,3) alkyl sulfates than with the primary alkyl sulfates. With regard to the random secondary alkyl sulfates (i.e., secondary alkyl sulfates with the sulfate group at positions such as the 4, 5, 6, 7, etc. secondary carbon atoms), such materials tend to be tacky solids or pastes, and thus do not afford the processing advantages associated with the secondary (2,3) alkyl sulfates when formulating detergent bars, granules or tablets. Moreover, sudsing of the random alkyl sulfates is also less than with the secondary (2,3) alkyl sulfates herein. This is an important consideration for hand dishwashing, where users expect high, persistent sudsing. It is preferred that the secondary (2,3) alkyl sulfates be substantially free (i.e., contain less than about 20%, more preferably less than about 10%, most preferably less than about 5%) of such random secondary alkyl sulfates.
One additional advantage of the secondary (2,3) alkyl sulfate surfactants herein over other positional or "random" alkyl sulfate isomers is in regard to the improved benefits afforded by said secondary (2,3) alkyl sulfates with respect to soil redeposition in the context of fabric laundering operations. As is well-known to users, laundry detergents loosen soils from fabrics being washed and suspend the soils in the aqueous laundry liquor. However, as is well-known to detergent formulators, some portion of the suspended soil can be redeposited back onto the fabrics. Thus, some redistribution and redeposition of the soil onto all fabrics in the load being washed can occur. This, of course, is undesirable and can lead to the phenomenon known as fabric "greying". (As a simple test of the redeposition characteristics of any given laundry detergent formulation, unsoiled white "tracer" cloths can be included with the soiled fabrics being laundered. At the end of the laundering operation the extent that the white tracers deviate from their initial degree of whiteness can be measured photometrically or estimated visually by skilled observers. The more the tracers' whiteness is retained, the less soil redeposition has occurred.)
It has now been determined that the secondary (2,3) alkyl sulfates afford substantial advantages in soil redeposition characteristics over the other positional isomers of secondary alkyl sulfates in laundry detergents, as measured by the cloth tracer method noted above. Thus, the selection of secondary (2,3) alkyl sulfate surfactants according to the practice of this invention which preferably are substantially free of other positional secondary isomers unexpectedly assist in solving the problem of soil redeposition in a manner not heretofore recognized.
It is to be noted that the secondary (2,3) alkyl sulfates used herein are quite different in several important properties from the secondary olefin sulfonates (e.g., U.S. Patent 4,064,076, Klisch et al, 12/20/77); accordingly, the secondary sulfonates are not the focus of the present invention.
The preparation of the secondary (2,3) alkyl sulfates of the type useful herein can be carried out by the addition of H2SO4 to olefins. A typical synthesis using o-olefins and sulfuric acid is
disclosed in U.S. Patent 3,234,258, Morris, or in U.S. Patent 5,075,041, Lutz, granted December 24, 1991. The synthesis, conducted in solvents which afford the secondary (2,3) alkyl sulfates on cooling, yields products which, when purified to remove the unreacted materials, randomly sulfated materials, unsulfated by-products such as Cio and higher alcohols, secondary olefin sulfonates, and the like, are typically 90+% pure mixtures of 2- and 3-sulfated materials (some sodium sulfate may be present) and are white, non-tacky, apparently crystalline, solids. Some 2,3-disulfates may also be present, but generally comprise no more than 5% of the mixture of secondary (2,3) alkyl mono-sulfates. Such materials are available as under the name "DAN", e.g., "DAN 200" from Shell Oil Company.
If increased solubility of the "crystalline" secondary (2,3) alkyl sulfate surfactants is desired, the formulator may wish to employ mixtures of such surfactants having a mixture of alkyl chain lengths. Thus, a mixture of C12-C18 alkyl chains will provide an increase in solubility over a secondary (2,3) alkyl sulfate wherein the alkyl chain is, say, entirely Cχ6- The solubility of the secondary (2,3) alkyl sulfates can also be enhanced by the addition thereto of other surfactants such as the alkyl ethoxylates or other nonionic surfactants, or by any other material which decreases the crystallinity of the secondary (2,3) alkyl sulfates. Such crystallinity-interrupting materials are typically effective at levels of 20%, or less, of the secondary (2,3) alkyl sulfate.
When formulating liquid and gel compositions, especially clear liquids, it is preferred that the secondary (2,3) alkyl sulfate surfactants contain less than about 3% sodium sulfate, preferably less than about 1% sodium sulfate. In and of itself, sodium sulfate is an innocuous material. However, it dissolves and adds to the ionic "load" in aqueous media, and this can contribute to phase separation in liquid compositions and to gel breaking in the gel compositions. Various means can be used to lower the sodium sulfate content of the secondary (2,3) alkyl sulfates. For example, when the H2SO4 addition to the olefin is completed, care can be taken to remove unreacted H2SO4 before the acid form of the secondary (2,3)
alkyl sulfate is neutralized. In another method, the sodium salt form of the secondary (2,3) alkyl sulfate which contains sodium sulfate can be rinsed with water at a temperature near or below the Krafft temperature of the sodium secondary (2,3) alkyl sul- fate. This will remove a2Sθ4 with only minimal loss of the desired, purified sodium secondary (2,3) alkyl sulfate. Of course, both procedures can be used, the first as a pre- neutralization step and the second as a post-neutralization step.
The term "Krafft temperature" as used herein is a term of art which is well-known to workers in the field of surfactant sciences. Krafft temperature is described by K. Shinoda in the text "Principles of Solution and Solubility", translation in collaboration with Paul Becher, published by Marcel Dekker, Inc. 1978 at pages 160-161. Stated succinctly, the solubility of a surface active agent in water increases rather slowly with temperature up to that point, i.e., the Krafft temperature, at which the solubility evidences an extremely rapid rise. At a temperature approximately 4 * C above the Krafft temperature a solution of almost any composition becomes a homogeneous phase. In general, the Krafft temperature of any given type of surfactant, such as the secondary (2,3) alkyl sulfates herein which comprise an anionic hydrophilic sulfate group and a hydrophobic hydrocarbyl group, will vary with the chain length of the hydrocarbyl group. This is due to the change in water solubility with the variation in the hydrophobic portion of the surfactant molecule.
In the practice of the present invention the formulator may optionally wash the secondary (2,3) alkyl sulfate surfactant which is contaminated with sodium sulfate with water at a temperature that is no higher than the Krafft temperature, and which is preferably lower than the Krafft temperature, for the particular secondary (2,3) alkyl sulfate being washed. This allows the sodium sulfate to be dissolved and removed with the wash water, while keeping losses of the secondary (2,3) alkyl sulfate into the wash water to a minimum.
Under circumstances where the secondary (2,3) alkyl sulfate surfactant herein comprises a mixture of alkyl chain lengths, it will be appreciated that the Krafft temperature will not be a
single point but, rather, will be denoted as a "Krafft boundary". Such matters are well-known to those skilled in the science of surfactant/solution measurements. In any event, for such mixtures of secondary (2,3) alkyl sulfates, it is preferred to conduct the sodium sulfate removal operation at a temperature which is below the Krafft boundary, and preferably below the Krafft temperature of the shortest chain-length surfactant present in such mixtures, since this avoids excessive losses of secondary (2,3) alkyl sulfate to the wash solution. For example, for C 6 secondary sodium alkyl (2,3) sulfate surfactants, it is preferred to conduct the washing operation at temperatures below about 30 * C, preferably below about 20 * C. It will be appreciated that changes in the cation will change the preferred temperatures for washing the secondary (2,3) alkyl sulfates, due to changes in the Krafft temperature.
The washing process can be conducted batchwise by suspending wet or dry secondary (2,3) alkyl sulfates in sufficient water to provide 10-50% solids, typically for a mixing time of at least 10 minutes at about 22'C (for a C\ζ secondary [2,3] alkyl sulfate), followed by pressure filtration. In a preferred mode, the slurry will comprise somewhat less than 35% solids, inasmuch as such slurries are free-flowing and amenable to agitation during the washing process.
As an additional benefit, the washing process also reduces the levels of organic contaminants which comprise the random secondary alkyl sulfates noted above.
Calcium Ion Source - The present compositions will contain at least about 0.05% by weight of a water-soluble source of calcium ions, further details of which, along with a nonlimiting listing of suitable and convenient calcium ion sources, are listed herein¬ after under "Enzyme Stabilizers".
Detersive Adjunct Materials Enzymes - Detersive enzymes can optionally be included in the detergent formulations herein for a wide variety of fabric laun- dering purposes, including removal of protein-based, carbohydrate- based, or triglyceride-based stains, for example, for the prevention of refugee dye transfer, and for fabric restoration. The enzymes to be incorporated include proteases, amylases,
lipases, cellulases, and peroxidases, as well as mixtures thereof. Other types of enzymes may also be included. They may be of any suitable origin, such as vegetable, animal, bacterial, fungal and yeast origin. However, their choice is governed by several factors such as pH-activity and/or stability optima, thermostabil- ity, stability versus active detergents, builders and so on. In this respect bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases, and fungal cellulases.
Enzymes are normally incorporated at levels sufficient to provide up to about 5 mg by weight, more typically about 0.01 mg to about 3 mg, of active enzyme per gram of the composition. Stated otherwise, the compositions herein will typically comprise from about 0.001% to about 5%, preferably 0.1%-1%, by weight of a commercial enzyme preparation. Protease enzymes are usually present in such commercial preparations at levels sufficient to provide from 0.005 to 0.1 Anson units (AU) of activity per gram of composition.
Suitable examples of proteases are the subtilisins which are obtained from particular strains of B.subtilis and B.licheniforms. Another suitable protease is obtained from a strain of Bacillus, having maximum activity throughout the pH range of 8-12, developed and sold by Novo Industries A/S under the registered trade name ESPERASE. The preparation of this enzyme and analogous enzymes is described in British Patent Specification No. 1,243,784 of Novo. Proteolytic enzymes suitable for removing protein-based stains that are commercially available include those sold under the tradenames ALCALASE and SAVINASE by Novo Industries A/S (Denmark) and MAXATASE by International Bio-Synthetics, Inc. (The Netherlands). Other proteases include Protease A (see European Patent Application 130,756, published January 9, 1985) and Protease B (see European Patent Application Serial No. 87303761.8, filed April 28, 1987, and European Patent Application 130,756, Bott et al, published January 9, 1985).
Amylases include, for example, α-amylases described in British Patent Specification No. 1,296,839 (Novo), RAPIDASE, International Bio-Synthetics, Inc. and TERMAMYL, Novo Industries.
The cellulases usable in the present invention include both bacterial or fungal cellulase. Preferably, they will have a pH
optimum of between 5 and 9.5. Suitable cellulases are disclosed in U.S. Patent 4,435,307, Barbesgoard et al, issued March 6, 1984, which discloses fungal cellulase produced from Humicola insolens and Humicola strain DSM1800 or a cellulase 212-producing fungus belonging to the genus Aeromonas, and cellulase extracted from the hepatopancreas of a marinς- mollusk (Dolabella Auricula Solander). Suitable cellulases are also disclosed in GB-A-2.075.028; GB-A-2.095.275 and DE-OS-2.247.832.
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 British Patent 1,372,034. See also lipases in Japanese Patent Application 53-20487, laid open to public inspection on February 24, 1978. This lipase is available from Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name Lipase P "Amano," hereinafter referred to as "Amano-P." Other commercial lipases include Amano-CES, lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var. l ipolyticum NRRLB 3673, commercially available from Toyo Jozo Co., Tagata, Japan; and further Chromobacter viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands, and lipases ex Pseudomonas gladioli . The LIPOLASE enzyme derived from Humico la lanuginosa and commercially available from Novo (see also EPO 341,947) is a preferred lipase for use herein. Peroxidase enzymes are used in combination with oxygen sources, e.g., percarbonate, perborate, persulfate, hydrogen peroxide, etc. They are used for "solution bleaching," i.e. to prevent transfer of dyes or pigments removed from substrates during wash operations to other substrates in the wash solution. Peroxidase enzymes are known in the art, and include, for example, horseradish peroxidase, ligninase, and haloperoxidase such as chloro- and bromo-peroxidase. Peroxidase-containing detergent compositions are disclosed, for example, in PCT International Application WO 89/099813, published October 19, 1989, by 0. Kirk, assigned to Novo Industries A/S.
A wide range of enzyme materials and means for their incorp¬ oration into synthetic detergent granules is also disclosed in U.S. Patent 3,553,139, issued January 5, 1971 to McCarty et al ().
Enzymes are further disclosed in U.S. Patent 4,101,457, Place et al, issued July 18, 1978, and in U.S. Patent 4,507,219, Hughes, issued March 26, 1985, both. Enzyme materials useful for liquid detergent formulations, and their incorporation into such formulations, are disclosed in U.S. Patent 4,261,868, Hora et al , issued April 14, 1981. Enzymes for use in detergents can be stabilized by various techniques. Enzyme stabilization techniques are disclosed and exemplified in U.S. Patent 4,261,868, issued April 14, 1981 to Horn, et al, U.S. Patent 3,600,319, issued August 17, 1971 to Gedge, et al , and European Patent Application Publication No. 0 199405, Application No. 86200586.5, published October 29, 1986, Venegas. Enzyme stabilization systems are also described, for example, in U.S. Patents 4,261,868, 3,600,319, and 3,519,570. Enzv e Stabilizers - The enzymes optionally employed herein are stabilized by the presence of water-soluble sources of calcium ions in the finished compositions which provide calcium ions to the enzymes. Additional stability can be provided by the presence of various other art-disclosed stabilizers, especially borate species: see Severson, U.S. 4,537,706, cited above. Typical detergents, especially liquids, will comprise from about 1 to about 30, preferably from about 2 to about 20, more preferably from about 5 to about 15, and most preferably from about 8 to about 12, millimoles of calcium ion per liter of finished composition. This can vary somewhat, depending on the amount of enzyme present and its response to the calcium ions. The level of calcium ion should be selected so that there is always some minimum level available for the enzyme, after allowing for complexation with builders, fatty acids, etc., in the composition. Any water-soluble calcium salt can be used as the source of calcium ion, including, but not limited to, calcium chloride, calcium sulfate, calcium malate, calcium hydroxide, calcium formate, and calcium acetate. A small amount of calcium ion, generally from about 0.05 to about 0.4 millimoles per liter, is often also present in the composition due to calcium in the enzyme slurry and formula water. In solid detergent compositions the formulation may include a sufficient quantity of a water-soluble
calcium ion source to provide such amounts in the laundry liquor. In the alternative, natural water hardness may suffice.
It is to be understood that the foregoing levels of calcium ions are sufficient to provide enzyme stability. In the present invention, sufficient calcium ions are added to the compositions to provide the desired additional measure of grease removal performance provided by this invention. Accordingly, the compositions herein will typically comprise from about 0.05% to about 2% by weight of a water-soluble source of calcium ions, which is more than sufficient to stabilize any enzymes which may optionally be present and which provides additional cleaning.
The compositions herein may also optionally, but preferably, contain various additional stabilizers, especially borate-type stabilizers. Typically, such stabilizers will be used at levels in the compositions from about 0.25% to about 10%, preferably from about 0.5% to about 5%, more preferably from about 0.75% to about 3%, by weight of boric acid or other borate compound capable of forming boric acid in the composition (calculated on the basis of boric acid). Boric acid is preferred, although other compounds such as boric oxide, borax and other alkali metal borates (e.g., sodium ortho-, meta- and pyroborate, and sodium pentaborate) are suitable. Substituted boric acids (e.g., phenylboronic acid, butane boronic acid, and p-bromo phenylboronic acid) can also be used in place of boric acid. In addition to enzymes, the compositions herein can option¬ ally include one or more other detergent adjunct materials or other materials for assisting or enhancing cleaning performance, treatment of the substrate to be cleaned, or to modify the aesthetics of the detergent composition (e.g., perfumes, colorants, dyes, etc.). The following are illustrative examples of such other adjunct materials.
Builders - Detergent builders can optionally be included in the compositions herein to assist in controlling mineral hardness. Inorganic as well as organic builders can be used. Builders are typically used in fabric laundering compositions to assist in the removal of particulate soils.
The level of builder can vary widely depending upon the end use of the composition and its desired physical form. For "light
duty" liquids such as those used for dishwashing, typically no builder is present. When present, the compositions will typically comprise at least about 1% builder. Liquid formulations typically comprise from about 5% to about 50%, more typically about 5% to about 30%, by weight, of detergent builder. Lower or higher levels of builder, however, are not meant to be excluded. Gel compositions can tolerate only low levels of water-soluble builders, generally no more than about 5%-10%. Granular and bar compositions can contain from 10%-60% by weight of builder. If a solid or bar product is desired, the insoluble zeolite builders and/or silicate builders can be employed therein. Useful aluminosilicate ion exchange materials are commercially available. These aluminosilicates can be crystalline or amorphous in structure and can be naturally-occurring aluminosilicates or synthetically derived. A method for producing aluminosilicate ion exchange materials is disclosed in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein are available under the designations Zeolite A, Zeolite P (B), and Zeolite X. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange material has the formula: ai2.(Alθ2)l2(Siθ2)i2]-xH2θ wherein x is from about 20 to about 30, especially about 27. This material is known as Zeolite A. Preferably, the aluminosilicate has a particle size of about 0.1-10 microns in diameter.
Useful layered silicate builders are disclosed in U.S. 4,664,839. NaSKS-6 is the trademark for a crystalline layered silicate marketed by Hoechst (commonly abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na SKS-6 silicate builder does not contain aluminum. NaSKS-6 has the delta-Na2Siθ5 morphology form of layered silicate. It can be prepared by methods such as those described in German DE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a highly preferred layered silicate for use herein, but other such layered silicates, such as those having the general formula aMSi x θ +i-yH2θ wherein M is sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and y is a number from 0 to 20, preferably 0 can be used herein. Various other layered silicates from Hoechst include NaSKS-5, NaS S-7 and
NaSKS-11, as the alpha, beta and gamma forms. As noted above, the delta-Na2Siθ5 (NaSKS-6 form) is most preferred for use herein.
Organic detergent builders suitable for the purposes of the present invention include, but are not restricted to, a wide variety of polycarboxylate compounds. As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably at least 3 carboxylates. Polycarboxylate builder can generally be added to the composition in acid form, but can also be added in the form of a neutralized salt. When utilized in salt form, alkali metals, such as sodium, potassium, and lithium, or alkanolammonium salts are preferred.
Included among the polycarboxylate builders are a variety of categories of useful materials. One important category of polycarboxylate builders encompasses the ether polycarboxylates, including oxydisuccinate, as disclosed in Berg, U.S. Patent 3,128,287, issued April 7, 1964, and Lamberti et al , U.S. Patent 3,635,830, issued January 18, 1972. See also "TMS/TDS" builders of U.S. Patent 4,663,071, issued to Bush et al, on May 5, 1987. Suitable ether polycarboxylates also include cyclic compounds, particularly alicyclic compounds, such as those described in U.S. Patents 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903.
Other useful detergency builders include the ether hydroxy- polycarboxylates, copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxy benzene-2, 4, 6-trisul- phonic acid, and carboxymethyloxysuccinic acid, the various alkali metal, ammonium and substituted ammonium salts of polyacetic acids such as ethylenediamine tetraacetic acid and nitrilotriacetic acid, as well as polycarboxylates such as mellitic acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricar- boxylic acid, carboxymethyloxysuccinic acid, and soluble salts thereof.
Citrate builders, e.g., citric acid and soluble salts thereof (particularly sodium salt), are polycarboxylate builders of particular importance for heavy duty liquid laundry detergent formulations due to their availability from renewable resources and their biodegradability. Citrates can also be used in granular compositions, especially in combination with zeolite and/or
layered silicate builders. Oxydisuccinates are also especially useful in such compositions and combinations.
Also suitable in the detergent compositions of the present invention are the 3,3-dicarboxy-4-oxa-l,6-hexanedioates and the related compounds disclosed in U.S. Patent 4,566,984, Bush, issued January 28, 1986. Useful succinic acid builders include the C5-C20 alkyl and alkenyl succinic acids and salts thereof. A particularly preferred compound of this type is dodecenylsuccinic acid. Specific examples of succinate builders include: laurylsuc- cinate, myristylsuccinate, palmitylsuccinate, 2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and the like. Laurylsuccin- ates are the preferred builders of this group, and are described in European Patent Application 86200690.5/0,200,263, published November 5, 1986. Other suitable polycarboxylates are disclosed in U.S. Patent 4,144,226, Crutchfield et al , issued March 13, 1979 and in U.S. Patent 3,308,067, Diehl, issued March 7, 1967. See also Diehl U.S. Patent 3,723,322.
Fatty acids, e.g., C12- 18 monocarboxylic acids, can also be incorporated into the compositions alone, or in combination with the aforesaid builders, especially citrate and/or the succinate builders, to provide additional builder activity. Such use of fatty acids will generally result in a diminution of sudsing, which should be taken into account by the formulator. In situations where phosphorus-based builders can be used, and especially in the formulation of compositions used for hand- laundering operations, the various alkali metal phosphates such as the well-known sodium tripolyphosphates, sodium pyrophosphate and sodium orthophosphate can be used. Phosphonate builders such as ethane-l-hydroxy-l,l-diphosphonate and other known phosphonates (see, for example, U.S. Patents 3,159,581; 3,213,030; 3,422,021; 3,400,148 and 3,422,137) can also be used.
Bleaching Compounds - Bleaching Aoents and Bleach Activators - The detergent compositions herein may optionally contain bleaching agents or bleaching compositions containing a bleaching agent and one or more bleach activators. When present, bleaching agents will typically be at levels of from about 1% to about 30%, more typically from about 5% to about 20%, of the detergent
composition, especially for fabric laundering. If present, the amount of bleach activators 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.
The bleaching agents used herein can be any of the bleaching agents useful for detergent compositions in textile cleaning, hard surface cleaning, or other cleaning purposes that are now known or become known. These include oxygen bleaches as well as other bleaching agents. Perborate bleaches, e.g., sodium perborate (e.g., mono- or tetra-hydrate) can be used herein.
One category of bleaching agent that can be used without restriction encompasses percarboxylic acid bleaching agents and salts thereof. Suitable examples of this class of agents include magnesium monoperoxyphthalate hexahydrate, the magnesium salt of meta-chloro perbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid and diperoxydodecanedioic acid. Such bleaching agents are dis¬ closed in U.S. Patent 4,483,781, Hartman, issued November 20, 1984, U.S. Patent Application 740,446, Burns et al , filed June 3, 1985, European Patent Application 0,133,354, Banks et al , pub¬ lished February 20, 1985, and U.S. Patent 4,412,934, Chung et al, issued November 1, 1983. Highly preferred bleaching agents also include 6-nonylamino-6-oxoperoxycaproic acid as described in U.S. Patent 4,634,551, issued January 6, 1987 to Burns et al . Peroxygen bleaching agents can also be used. Suitable peroxygen bleaching compounds include sodium carbonate peroxy- hydrate and equivalent "percarbonate" bleaches, sodium pyrophos- phate peroxyhydrate, urea peroxyhydrate, and sodium peroxide. Persulfate bleach (e.g., 0X0NE, manufactured commercially by DuPont) can also be used.
Mixtures of bleaching agents can also be used. Peroxygen bleaching agents, the perborates, the percarbon- ates, etc., are preferably combined with bleach activators, which lead to the in situ production in aqueous solution (i.e., during the washing process) of the peroxy acid corresponding to the bleach activator. Various nonlimiting examples of activators are disclosed in U.S. Patent 4,915,854, issued April 10, 1990 to Mao et al, and U.S. Patent 4,412,934. The nonanoyloxybenzene
sulfonate (NOBS) and tetraacetyl ethylene diamine (TAED) activa¬ tors are typical, and mixtures thereof can also be used. See also U.S. 4,634,551 for other typical bleaches and activators useful herein. Bleaching agents other than oxygen bleaching agents are also known in the art and can be utilized herein. One type of non- oxygen bleaching agent of particular interest includes photo- activated bleaching agents such as 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 sulfonated zinc phthalocyanine.
Polymeric Soil Release Agent - Any polymeric soil release agent known to those skilled in the art can optionally be employed in the laundry compositions and laundry cleaning processes of this invention. Polymeric soil release agents are characterized by having both hydrophilic segments, to hydrophilize the surface of hydrophobic fibers, such as polyester and nylon, and hydrophobic segments, to deposit upon hydrophobic fibers and remain adhered thereto through completion of washing and rinsing cycles and, thus, serve as an anchor for the hydrophilic segments. This can enable stains occurring subsequent to treatment with the soil release agent to be more easily cleaned in later washing procedures. The polymeric soil release agents useful herein especially include those soil release agents having: (a) one or more nonionic hydrophile components consisting essentially of (i) polyoxyethylene segments with a degree of polymerization of at least 2, or (ii) oxypropylene or polyoxypropylene segments with a degree of polymerization of from 2 to 10, wherein said hydrophile segment does not encompass any oxypropylene unit unless it is bonded to adjacent moieties at each end by ether linkages, or (iii) a mixture of oxyalkylene units comprising oxyethylene and from 1 to about 30 oxypropylene units wherein said mixture con- tains a sufficient amount of oxyethylene units such that the hydrophile component has hydrophilicity great enough to increase the hydrophilicity of conventional polyester synthetic fiber surfaces upon deposit of the soil release agent on such surface,
said hydrophile segments preferably comprising at least about 25% oxyethylene units and more preferably, especially for such compon¬ ents having about 20 to 30 oxypropylene units, at least about 50% oxyethylene units; or (b) one or more hydrophobe components comprising (i) C3 oxyalkylene terephthalate segments, wherein, if said hydrophobe components also comprise oxyethylene terephthal¬ ate, the ratio of oxyethylene terephthalate:C3 oxyalkylene tere¬ phthalate units is about 2:1 or lower, (ii) C4-C6 alkylene or oxy C -C6 alkylene segments, or mixtures therein, (iii) poly (vinyl ester) segments, preferably poly(vinyl acetate), having a degree of polymerization of at least 2, or (iv) C1-C4 alkyl ether or C4 hydroxyalkyl ether substituents, or mixtures therein, wherein said substituents are present in the form of C1-C4 alkyl ether or C4 hydroxyalkyl ether cellulose derivatives, or mixtures therein, and such cellulose derivatives are amphiphilic, whereby they have a sufficient level of C1-C4 alkyl ether and/or C4 hydroxyalkyl ether units to deposit upon conventional polyester synthetic fiber surfaces and retain a sufficient level of hydroxyls, once adhered to such conventional synthetic fiber surface, to increase fiber surface hydrophilicity, or a combination of (a) and (b).
Typically, the polyoxyethylene segments of (a)(i) will have a degree of polymerization of from 2 to about 200, although higher levels can be used, preferably from 3 to about 150, more prefer¬ ably from 6 to about 100. Suitable oxy C4-C6 alkylene hydrophobe segments include, but are not limited to, end-caps of polymeric soil release agents such as Mθ3S(CH2)nOCH2CH2θ-, where M is sodium and n is an integer from 4-6, as disclosed in U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink.
Polymeric soil release agents useful in the present invention also include cellulosic derivatives such as hydroxyether cellu¬ losic polymers, copolymeric blocks of ethylene terephthalate or propylene terephthalate with polyethylene oxide or polypropylene oxide terephthalate, and the like. Such agents are commercially available and include hydroxyethers of cellulose such as METH0CEL (Dow). Cellulosic soil release agents for use herein also include those selected from the group consisting of C1-C4 alkyl and C4 hydroxyalkyl cellulose; see U.S. Patent 4,000,093, issued December 28, 1976 to Nicol, et al .
Soil release agents characterized by poly(vinyl ester) hydrophobe segments include graft copolymers of poly(vinyl ester), e.g., Cj-Cβ vinyl esters, preferably poly(vinyl acetate) grafted onto polyalkylene oxide backbones, such as polyethylene oxide backbones. See European Patent Application 0 219 048, published April 22, 1987 by Kud, et al . Commercially available soil release agents of this kind include the SOKALAN type of material, e.g., SOKALAN HP-22, available from BASF (West Germany).
One type of preferred soil release agent is a copolymer having random blocks of ethylene terephthalate and polyethylene oxide (PEO) terephthalate. The molecular weight of this polymeric soil release agent is in the range of from about 25,000 to about 55,000. See U.S. Patent 3,959,230 to Hays, issued May 25, 1976 and U.S. Patent 3,893,929 to Basadur issued July 8, 1975. Another preferred polymeric soil release agent is a polyester with repeat units of ethylene terephthalate units containing 10-15% by weight of ethylene terephthalate units together with 90-80% by weight of polyoxyethylene terephthalate units, derived from a polyoxyethylene glycol of average molecular weight 300-5,000. Examples of this polymer include the commercially available material ZELCON 5126 (from Dupont) and MILEASE T (from ICI). See also U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.
Another preferred polymeric soil release agent is a sulfonated product of a substantially linear ester oligomer comprised of an oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and terminal moieties covalently attached to the backbone. These soil release agents are described fully in U.S. Patent 4,968,451, issued November 6, 1990 to J. J. Scheibel and E. P. Gosselink.
Other suitable polymeric soil release agents include the terephthalate polyesters of U.S. Patent 4,711,730, issued December 8, 1987 to Gosselink et al , the anionic end-capped oligomeric esters of U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink, and the block polyester oligomeric compounds of U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.
Preferred polymeric soil release agents also include the soil release agents of U.S. Patent 4,877,896, issued October 31, 1989 to Maldonado et al , which discloses anionic, especially sulfo- aroyl, end-capped terephthalate esters. If utilized, soil release agents will generally comprise from about 0.01% to about 10.0%, by weight, of the detergent composi¬ tions herein, typically from about 0.1% to about 5%, preferably from about 0.2% to about 3.0%.
Clay Soil Removal/Anti-redeposition Agents - The laundry compositions of the present invention can also optionally contain water-soluble ethoxylated amines having clay soil removal and anti-redeposition properties. Granular detergent compositions which contain these compounds typically contain from about 0.01% to about 10.0% by weight of the water-soluble ethoxylated amines; liquid detergent compositions typically contain about 0.01% to about 5%.
The most preferred soil release and anti-redeposition agent is ethoxylated tetraethylenepentamine. Exemplary ethoxylated amines are further described in U.S. Patent 4,597,898, VanderMeer, issued July 1, 1986. Another group of preferred clay soil removal/antiredeposition agents are the cationic compounds dis¬ closed 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 can also be utilized in the compositions herein. Another type of preferred anti- redeposition agent includes the carboxy methyl cellulose (CMC) materials. These materials are well known in the art.
Chelating Agents - Laundry compositions, especially with bleaches, may also contain various chelants, typically at levels of 0.1%-3% by weight. Chelants such as the amino phosphonates (DEQUEST) can be used. A preferred biodegradable chelant is ethylenediamine disuccinate (EDDS); see U.S. Patent 4,704,233,
November 3, 1987, to Hartman and Perkins. Other such chelants are well-known in the trade and patent literature.
Polymeric Dispersing Agents - Polymeric dispersing agents can advantageously be utilized at levels from about 0.1% to about 7%, by weight, in the laundry compositions herein, especially in the presence of zeolite and/or layered silicate builders. Suitable polymeric dispersing agents include polymeric polycarboxylates and polyethylene glycols, although others known in the art can also be used. It is believed, though it is not intended to be limited by theory, that polymeric dispersing agents enhance overall detergent builder performance, when used in combination with other builders (including lower molecular weight polycarboxylates) by crystal growth inhibition, particulate soil release peptization, and anti-redeposition. Polymeric polycarboxylate materials can be prepared by polymerizing or copolymerizing suitable unsaturated monomers, preferably in their acid form. Unsaturated monomeric acids that can be polymerized to form suitable polymeric polycarboxylates include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, esaconic acid, citraconic acid and methylenemalonic acid. The presence in the polymeric polycarboxylates herein of monomeric segments, containing no carboxyl te radicals such as vinylmethyl ether, styrene, ethylene, etc. is suitable provided that such segments do not constitute more than about 40% by weight.
Particularly suitable polymeric polycarboxylates can be derived from acrylic acid. Such acrylic acid-based polymers which are useful herein are the water-soluble salts of polymerized acrylic acid. The average molecular weight of such polymers in the acid form preferably ranges from about 2,000 to 10,000, more preferably from about 4,000 to 7,000 and most preferably from about 4,000 to 5,000. Water-soluble salts of such acrylic acid polymers can include, for example, the alkali metal, ammonium and substituted ammonium salts. Soluble polymers of this type are known materials. Use of polyacrylates of this type in detergent compositions has been disclosed, for example, in Diehl, U.S. Patent 3,308,067, issued March 7, 1967.
Acrylic/maleic-based copolymers may also be used as a preferred component of the dispersing/anti-redeposition agent. Such materials include the water-soluble salts of copolymers of acrylic acid and maleic acid. The average molecular weight of such copolymers in the acid form preferably ranges from about 2,000 to 100,000, more preferably from about 5,000 to 75,000, most preferably from about 7,000 to 65,000. The ratio of acrylate to maleate segments in such copolymers will generally range from about 30:1 to about 1:1, more preferably from about 10:1 to 2:1. Water-soluble salts of such acrylic acid/maleic acid copolymers can include, for example, the alkali metal, ammonium and substituted ammonium salts. Soluble acrylate/maleate copolymers of this type are known materials which are described in European Patent Application No. 66915, published December 15, 1982. Another polymeric material which can be included is poly¬ ethylene glycol (PEG). PEG can exhibit dispersing agent perform¬ ance as well as act as a clay soil removal/antiredeposition agent. Typical molecular weight ranges for these purposes range from about 500 to about 100,000, preferably from about 1,000 to about 50,000, more preferably from about 1,500 to about 10,000.
Polyaspartate and polyglutamate dispersing agents may also be used, especially in conjunction with zeolite builders.
Brightener - Any optical brighteners or other brightening or whitening agents known in the art can be incorporated at levels typically from about 0.05% to about 1.2%, by weight, into the laundry detergent compositions herein. Commercial optical bright¬ eners which may be useful in the present invention can be classi¬ fied 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). Specific examples of optical brighteners which are useful in the present compositions are those identified in U.S. Patent 4,790,856, issued to Wixon on December 13, 1988. These brighten¬ ers include the PH0RWHITE series of brighteners from Verona.
Other brighteners disclosed in this reference include: Tinopal UNPA, Tinopal CBS and Tinopal 5BM; available from Ciba-Geigy; Arctic White CC and Artie White CWD, available from Hilton-Davis, located in Italy; the 2-(4-styryl-phenyl)-2H- naphthol[l,2-d]- triazoles; 4,4'-bis- (l,2,3-triazol-2-yl)-stil- benes; 4,4'-bis- (styryl)bisphenyls; and the aminocoumarins. Specific examples of these brighteners include 4-methyl-7-diethyl- amino coumarin; l,2-bis(-benzimidazol-2-yl)ethylene; 1,3-diphenylphrazo ines; 2,5-bis(benzoxazol-2-yl)thiophene; 2-styryl-naphth-[l,2-d]oxazole; and 2-(stilbene-4-yl)-2H-naphtho- [l,2-d]triazole. See also U.S. Patent 3,646,015, issued February 29, 1972 to Hamilton.
Suds Suppressors - Compounds for reducing or suppressing the formation of suds can be incorporated into the compositions of the present invention. Suds suppression can be of particular importance under conditions such as those found in European-style front loading laundry washing machines, or in the concentrated detergency process of U.S. Patents 4,489,455 and 4,489,574, or when the detergent compositions herein optionally include a relatively high sudsing adjunct surfactant. A wide variety of materials may be used as suds suppressors, and suds suppressors are well known to those skilled in the art. See, for example, Kirk Othmer Encyclopedia of Chemical Technology, Third Edition, Volume 7, pages 430-447 (John Wiley & Sons, Inc., 1979). One category of suds suppressor of particular interest encompasses monocarboxylic fatty acids and soluble salts therein. See U.S. Patent 2,954,347, issued September 27, 1960 to Wayne St. John. The monocarboxylic fatty acids and salts thereof used as suds suppressor typically have hydrocarbyl chains of 10 to about 24 carbon atoms, preferably 12 to 18 carbon atoms. Suitable salts include the alkali metal salts such as sodium, potassium, and lithium salts, and ammonium and alkanolammonium salts.
The detergent compositions herein may also contain non- surfactant suds suppressors. These include, for example: high molecular weight hydrocarbons such as paraffin, fatty acid esters (e-9- » fatty acid triglycerides), fatty acid esters of monovalent alcohols, aliphatic C18- 0 ketones (e.g. stearone), etc. Other suds inhibitors include N-alkylated amino triazines such as tri- to hexa-alkylmelamines or di- to tetra-alkyldiamine chlortriazines
formed as products of cyanuric chloride with two or three moles of a primary or secondary amine containing 1 to 24 carbon atoms, propylene oxide, and monostearyl phosphates such as monostearyl alcohol phosphate ester and monostearyl di-alkali metal (e.g. K, Na, and Li) phosphates and phosphate esters. The hydrocarbons such as paraffin and haloparaffin can be utilized in liquid form. The liquid hydrocarbons will be liquid at room temperature and atmospheric pressure, and will have a pour point in the range of about -40 * C and about 5'C, and a minimum boiling point not less than about 110'C (atmospheric pressure). It is also known to utilize waxy hydrocarbons, preferrably having a melting point below about lOO'C. The hydrocarbons constitute a preferred category of suds suppressor for detergent compositions. Hydrocar¬ bon suds suppressors are described, for example, in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al . The hydrocar¬ bons, thus, include aliphatic, alicyclic, aromatic, and hetero- cyclic saturated or unsaturated hydrocarbons having from about 12 to about 70 carbon atoms. The term "paraffin," as used in this suds suppressor discussion, is intended to include mixtures of true paraffins and cyclic hydrocarbons.
Another preferred category of non-surfactant suds suppressors comprises silicone suds suppressors. This category includes the use of polyorganosiloxane oils, such as polydimethylsiloxane, dispersions or emulsions of polyorganosiloxane oils or resins, and combinations of polyorganosiloxane with silica particles wherein the polyorganosiloxane is chemisorbed of fused onto the silica. Silicone suds suppressors are well known in the art and are, for example, disclosed in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al and European Patent Application No. 89307851.9, published February 7, 1990, by Starch, M. S.
Other silicone suds suppressors are disclosed in U.S. Patent 3,455,839 which relates to compositions and processes for defoaming aqueous solutions by incorporating therein small amounts of polydimethylsiloxane fluids. Mixtures of silicone and silanated silica are described, for instance, in German Patent Application DOS 2,124,526. Silicone defoamers and suds controlling agents in granular detergent compositions are disclosed in U.S. Patent 3,933,672, Bartolotta et
al, and in U.S. Patent 4,652,392, Baginski et al , issued March 24, 1987.
An exemplary silicone based suds suppressor for use herein is a suds suppressing amount of a suds controlling agent consisting essentially of:
(i) polydimethylsiloxane fluid having a viscosity of from about 20 cs. to about 1500 cs. at 25'C;
(ii) from about 5 to about 50 parts per 100 parts by weight of (i) of siloxane resin composed of (CH3)3 Si0ι 2 units of Siθ2 units in a ratio of from (CH3)3 SiOι/2 units and to Siθ2 units of from about 0.6:1 to about 1.2:1; and
(iii) from about 1 to about 20 parts per 100 parts by weight of (i) of a solid silica gel;
In the preferred silicone suds suppressor used herein, the solvent for a continuous phase is made up of certain polyethylene glycols or polyethylene-polypropylene glycol copolymers or mixtures thereof (preferred), and not polypropylene glycol. The primary silicone suds suppressor is branched/crosslinked and not linear. To illustrate this point further, typical liquid laundry detergent compositions with controlled suds will optionally comprise from about 0.001 to about 1, preferably from about 0.01 to about 0.7, most preferably from abut 0.05 to about 0.5, weight
% of said silicone suds suppressor, which comprises (1) a nonaqueous emulsion of a primary antifoam agent which is a mixture of (a) a polyorganosiloxane, (b) a resinous siloxane or a silicone resin-producing silicone compound, (c) a finely divided filler material, and (d) a catalyst to promote the reaction of mixture components (a), (b) and (c), to form silanolates; (2) at least one nonionic silicone surfactant; and (3) polyethylene glycol or a copolymer of polyethylene-polypropylene glycol having a solubility in water at room temperature of more than about 2 weight %; and without polypropylene glycol. Similar amounts can be used in granular compositions, gels, etc. See also U.S. Patents 4,978,471, Starch, issued December 18, 1990, and 4,983,316,
Starch, issued January 8, 1991, and U.S. Patents 4,639,489 and
4,749.740, Aizawa et al at column 1, line 46 through column 4, line 35.
The silicone suds suppressor herein preferably comprises polyethylene glycol and a copolymer of polyethylene glycol/poly- propylene glycol, all having an average molecular weight of less than about 1,000, preferably between about 100 and 800. The polyethylene glycol and polyethylene/polypropylene copolymers herein have a solubility in water at room temperature of more than about 2 weight %, preferably more than about 5 weight %.
The preferred solvent herein is polyethylene glycol having an average molecular weight of less than about 1,000, more preferably between about 100 and 800, most preferably between 200 and 400, and a copolymer of polyethylene glycol/polypropylene glycol, preferably PPG 200/PEG 300. Preferred is a weight ratio of between about 1:1 and 1:10, most preferably between 1:3 and 1:6, of polyethylene glycol :copolymer of polyethylene-polypropylene glycol.
The preferred silicone suds suppressors used herein do not contain polypropylene glycol, particularly of 4,000 molecular weight. They also preferably do not contain block copolymers of ethylene oxide and propylene oxide, like PLUR0NIC L101. Other suds suppressors useful herein comprise the secondary alcohols (e.g., 2-alkyl alkanols) and mixtures of such alcohols with silicone oils, such as the silicones disclosed in U.S. 4,798,679, 4,075,118 and EP 150,872. The secondary alcohols include the C6-Cιβ alkyl alcohols having a Cχ-Ci6 chain. A preferred alcohol is 2-butyl octanol, which is available from Condea under the trademark IS0F0L 12. Mixtures of secondary alcohols are available under the trademark ISALCHEM 123 from Enichem. Mixed suds suppressors typically comprise mixtures of alcohol + silicone at a weight ratio of 1:5 to 5:1. For any detergent compositions to be used in automatic laundry washing machines, suds should not form to the extent that they overflow the washing machine. Suds suppressors, when utilized, are preferably present in a "suds suppressing amount." By "suds suppressing amount" is meant that the formulator of the composition can select an amount of this suds controlling agent that will sufficiently control the suds to result in a low-sudsing laundry detergent for use in automatic laundry washing machines.
The compositions herein will generally comprise from 0% to about 5% of suds suppressor. When utilized as suds suppressors, monocarboxylic fatty acids, and salts therein, will be present typically in amounts up to about 5%, by weight, of the detergent composition. Preferably, from about 0.5% to about 3% of fatty monocarboxylate suds suppressor is utilized. Silicone suds suppressors are typically utilized in amounts up to about 2.0%, by weight, of the detergent composition, although higher amounts may be used. This upper limit is practical in nature, due primarly to concern with keeping costs minimized and effectiveness of lower amounts for effectively controlling sudsing. Preferably from about 0.01% to about 1% of silicone suds suppressor is used, more preferably from about 0.25% to about 0.5%. As used herein, these weight percentage values include any silica that may be utilized in combination with polyorganosiloxane, as well as any adjunct materials that may be utilized. Monostearyl phosphate suds suppressors are generally utilized in amounts ranging from about 0.1% to about 2%, by weight, of the composition. Hydrocarbon suds suppressors are typically utilized in amounts ranging from about 0.01% to about 5.0%, although higher levels can be used. The alcohol suds suppressors are typically used at 0.2%-3% by weight of the finished compositions.
In addition to the foregoing ingredients, the surfactant compositions herein can also be used with a variety of other adjunct ingredients which provide still other benefits in various compositions within the scope of this invention. The following illustrates a variety of such adjunct ingredients, but is not intended to be limiting therein.
Fabric Softeners - Various through-the-wash fabric softeners, especially the impalpable smectite clays of U.S. Patent 4,062,647, Storm and Nirschl, issued December 13, 1977, as well as other softener clays known in the art, can 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, Crisp et al , March 1, 1983 and U.S. Patent 4,291,071, Harris et al, issued September 22, 1981.
Adjunct Surfactants - The compositions herein can optionally contain various anionic, nonionic, zwitterionic, etc. surfactants. If used, such adjunct surfactants are typically present at levels of from about 1% to about 35% of the compositions. However, it is to be understood that the incorporation of adjunct anionic surfactants is entirely optional herein, inasmuch as the cleaning performance of the secondary (2,3) alkyl sulfates is excellent and these materials can be used to entirely replace such surfactants as the alkyl benzene sulfonates in fully-formulated detergent compositions. However, such adjunct surfactants, e.g., the betaines, sultaines and amine oxides, may be especially useful when high sudsing is desired, i.e., especially in hand dishwashing operations.
Nonlimiting examples of optional surfactants useful herein include the conventional Cn-Cis alkyl benzene sulfonates and primary and random alkyl sulfates (having due regard for the enzyme stability issues noted above), the Cio-Ciβ alkyl alkoxy sulfates (especially EO 1-5 ethoxy sulfates), the Cio-Cjβ alkyl alkoxy carboxylates (especially the EO 1-5 ethoxycarboxylates), the Cio-Ciβ alkyl polyglycosides and their corresponding sulfated polyglycosides, C12-C18 alpha-sulfonated fatty acid esters, C12-C18 alkyl and alkyl phenol alkoxylates (especially ethoxylates and mixed ethoxy/propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), Cio-Ciβ amine oxides, and the like. Other conven- tional useful surfactants are listed in standard texts.
One particular class of adjunct nonionic surfactants especially useful herein comprises the polyhydroxy fatty acid amides of the formula:
0 Rl (I) R2 - C - N - Z wherein: R 1 is H, Ci-Cs hydrocarbyl, 2-hydroxyethyl , 2-hydroxy- propyl, or a mixture thereof, preferably C1-C4 alkyl, more prefer¬ ably Ci or C2 alkyl, most preferably Ci alkyl (i.e., methyl); and R2 is a C5-C32 hydrocarbyl moiety, preferably straight chain C7-C19 alkyl or alkenyl, more preferably straight chain C9-C17 alkyl or alkenyl, most preferably straight chain C11-C19 alkyl or alkenyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 2 (in the
case of glyceraldehyde) or at least 3 hydroxyls (in the case of other reducing sugars) directly connected to the chain, or an alkoxylated derivative (preferably ethoxylated or propoxylated) thereof. Z preferably will be derived from a reducing sugar in a reductive amination reaction; more preferably Z is a glycityl moiety. Suitable reducing sugars include glucose, fructose, maltose, lactose, galactose, mannose, and xylose, as well as glyceraldehyde. As raw materials, high dextrose corn syrup, high fructose corn syrup, and high maltose corn syrup can be utilized as well as the individual sugars listed above. These corn syrups may yield a mix of sugar components for Z. It should be understood that it is by no means intended to exclude other suitable raw materials. Z preferably will be selected from the group consisting of -CH2-(CHOH) n -CH2θH, -CH(CH2θH)-(CHOH) n _ι- CH2OH, -CH2-(CHOH)2(CHOR')(CHOH)-CH2θH, where n is an integer from 1 to 5, inclusive, and R' is H or a cyclic mono- or poly- saccharide, and alkoxylated derivatives thereof. Most preferred are glycityls wherein n is 4, particularly -CH2-(CHOH)4-CH2θH.
In Formula (I), Rl can be, for example, N-methyl , N-ethyl, N-propyl, N-isopropyl, N-butyl, N-isobutyl, N-2-hydroxy ethyl, or N-2-hydroxy propyl . For highest sudsing, Rl is preferably methyl or hydroxyalkyl. If low sudsing is desired, Rl is preferably C2-C8 alkyl, especially n-propyl, iso-propyl, n-butyl, iso-butyl, pentyl, hexyl and 2-ethyl hexyl. R2-C0-N< can be, for example, cocamide, stearamide, oleamide, laura ide, myristamide, capricamide, palmitamide, tallowamide, etc.
While polyhydroxy fatty acid amides can be made by the process of Schwartz, U.S. 2,703,798, contamination with cyclized by-products and other colored materials can be problematic. As an overall proposition, the preparative methods described in WO-9,206,154 and WO-9,206,984 will afford high quality polyhydroxy fatty acid amides. The methods comprise reacting N-alkylamino polyols with, preferably, fatty acid methyl esters in a solvent using an alkoxide catalyst at temperatures of about 85 * C to provide high yields (90-98%) of polyhydroxy fatty acid amides having desirable low levels (typically, less than about 1.0%) of sub-optimally degradable cyclized by-products and also with
improved color and improved color stability, e.g., Gardner Colors below about 4, preferably between 0 and 2. (With compounds such as butyl, iso-butyl and n-hexyl, the ethanol introduced via the catalyst or generated during the reaction provides sufficient fluidization that the use of additional reaction solvent may be optional.) If desired, any unreacted N-alkylamino polyol remaining in the product can be acylated with an acid anhydride, e.g., acetic anhydride, maleic anhydride, or the like, to minimize the overall level of such residual amines in the product. Resi- dual sources of classical fatty acids, which can suppress suds, can be depleted by reaction with, for example, triethanolamine.
By "cyclized by-products" herein is meant the undesirable reaction by-products of the primary reaction wherein it appears that the multiple hydroxyl groups in the polyhydroxy fatty acid amides can form ring structures which are, in the main, not readily biodegradable. It will be appreciated by those skilled in the chemical arts that the preparation of the polyhydroxy fatty acid amides herein using the di- and higher saccharides such as maltose will result in the formation of polyhydroxy fatty acid amides wherein linear substituent Z (which contains multiple hydroxy substituents) is naturally "capped" by a polyhydroxy ring structure. Such materials are not cyclized by-products, as defined herein.
The foregoing polyhydroxy fatty acid amides can also be sulfated, e.g., by reaction with Sθ3/pyridine, and the resulting sulfated material used as an adjunct anionic surfactant herein.
Moreover, there has now been found to be a substantial and remarkable improvement in cold water solubility as a result of the blending and agglomeration of a mixture of the secondary (2,3) alkyl sulfates (SAS) herein with polyhydroxy fatty acid amide surfactants (PFAS), alkyl ethoxy!ate surfactants (AE) and primary alkyl sulfate surfactants (AS) to provide mixed SAS/PFAS/AE/AS particles. While not intending to be limited by theory, it appears that this increase in solubility may be due to the destruction of the crystallinity of the SAS. Whatever the reason, the improved solubility is of substantial benefit under cold water conditions (e.g., at temperatures in the range of 5'C to about 30'C) where the rate of solubility of detergent granules in an
aqueous washing liquor can be problematic. Of course, the improved solubility achieved herein is also of substantial benefit when preparing the modern compact or dense detergent granules where solubility can be problematic. Other Ingredients - A wide variety of other ingredients useful in detergent compositions can be included in the composi¬ tions herein, including other active ingredients, carriers, hydrotropes, processing aids, dyes or pigments, solvents for liquid formulations, etc. If high sudsing is desired, suds boosters such as the C10-C16 alkanolamides can be incorporated into the compositions, typically at 1%-10% levels. The C10-C14 monoethanol and diethanol amides illustrate a typical class of such suds boosters. Use of such suds boosters with high sudsing adjunct surfactants such as the amine oxides, betaines and sultaines noted above is also advantageous. If desired, soluble magnesium salts such as MgCl , MgSθ4, and the like, can be added at levels of, typically, 0.1%-2%, to provide additional sudsing.
Various detersive ingredients employed in the present compo¬ sitions optionally can be further stabilized by absorbing said ingredients onto a porous hydrophobic substrate, then coating said substrate with a hydrophobic coating. Preferably, the detersive ingredient is admixed with a surfactant before being absorbed into the porous substrate. In use, the detersive ingredient is released from the substrate into the aqueous washing liquor, where it performs its intended detersive function.
To illustrate this technique in more detail, a porous hydro¬ phobic silica (trademark SIPERNAT D10, DeGussa) is admixed with a proteolytic enzyme solution containing 3%-5% of C13-15 ethoxylated alcohol EO(7) nonionic surfactant. Typically, the enzyme/surfact- ant solution is 2.5 X the weight of silica. The resulting powder is dispersed with stirring in silicone oil (various silicone oil viscosities in the range of 500-12,500 can be used). The result¬ ing silicone oil dispersion is emulsified or otherwise added to the final detergent matrix. By this means, ingredients such as the aforementioned enzymes, bleaches, bleach activators, bleach catalysts, photoactivators, dyes, fluorescers, fabric conditioners and hydrolyzable surfactants can be "protected" for use in deter¬ gents, including liquid laundry detergent compositions.
Liquid detergent compositions can contain water and other solvents as carriers. Low molecular weight primary or secondary alcohols exemplified by methanol , ethanol, propanol , and isopropanol are suitable. Monohydric alcohols are preferred for solubilizing surfactant, but polyols such as those containing from 2 to about 6 carbon atoms and from 2 to about 6 hydroxy groups (e.g., 1,3-propanediol, ethylene glycol, glycerine, and 1,2- propanediol) can also be used. The compositions may contain from 5% to 90%, typically 10% to 50% of such carriers. The detergent compositions herein will preferably be formulated such that during use in aqueous laundering operations, the wash water will have a pH of between about 6.5 and about 11, preferably between about 7.5 and about 10.5. Liquid product formulations preferably have a pH between about 7.5 and about 9.5, more preferably between about 7.5 and about 9.0. Techniques for controlling pH at recommended usage levels include the use of buffers, alkalis, acids, etc., and are well known to those skilled in the art.
The following are typical, nonlimiting examples which illustrate the detergent compositions and uses of the secondary
(2,3) alkyl sulfates according to this invention. For most purposes, the preferred compositions are free of phosphate builders.
The liquid dishwashing detergents of Examples I-II are prepared by dissolving or dispersing the indicated ingredients in an aqueous carrier and adjusting the pH in the range of 6-8.
EXAMPLE I A dishwashing composition with high grease removal properties is as follows. Ingredient % (wt.)
C 2 N-methyl glucamide 9.0
C12 ethoxy (1) sulfate 5.0
Ci4 secondary (2,3) alkyl sulfate (Na)* 6.5 C12 ethoxy (2) carboxylate 4.5 C12 alcohol ethoxylate (4) 3.0
C 2 amine oxide 3.0
Sodium cumene sulfonate 2.0
Mg++ (as MgCl2) 0.2 Ca++ (as CaCl2) 0.4 Water Balance ♦ Purified to contain less than 1% Na2Sθ4. EXAMPLE II (A and B)
Ingredient % (wt . ) % (wt . )
Ci4 secondary (2,3) alkyl sulfate^ 12 8
C12-13 alkyl ether (3 avg.) sulfate 16 12 C 2-13 alkyl dimethyl amine oxide 2 2
Ci2-13 monoethanolamide 3 - -
C12 N-methylglucamide - - 8
Ca++ (as CaCl2) 0.6 0.1 Mg++ (as MgCl2) - . 0.4
Sodium cumene sulfonate
Sodium xylene sulfonate
Water, perfume, dye, minors, enzyme*** - Balance ---
*Ci2-l4 or Ci6 alkyl may be used; as Na salt **As NE0D0L 1E9
Compositions of the foregoing type exhibit good grease removal performance on dishware, with high sudsing, but with good mildness to the user's hands. The user of modern detergent compositions has appreciated the advantages of having such compositions available in a wide variety of forms, not only for convenience, but also for performance and aesthetic reasons. Accordingly, formulators of such compositions have made substantial efforts to provide detergent compositions as bars, flakes, spray-dried granules, and liquids. Most recently, a substantial proportion of consumers have begun using detergents which are available in gel form. In some Latin American countries, such as Venezuela, gel detergents are available in tub containers, and are especially popular and preferred for home dishwashing operations. Following local habits and practices, the gel is applied directly to a sponge or other wiping implement, and applied with water to the eating or cooking utensil being
cleansed. Accordingly, formulators have turned increasing atten¬ tion to the problems associated with the formulation of high quality, stable and economical gel detergent compositions.
The formulation of gels is a complex phenomenon involving the association of solute molecules in an aqueous medium. While a precise definition of the gel state is difficult, most aqueous gels can be considered as having most of the properties of a solid or semi-solid, while still containing as high as 99% water. Gels of the type used in gel detergents provided herein are typically in the form of gelatinized or gelled compositions which can have viscosities as high as 5,000,000 centipoise, and typically range from about 500,000 to about 4,000,000 centipoise.
A wide variety of means have been used to form gels, and standard formularies reveal that various commercial gums are used for this purpose in various consumer products. See, for example, M. G. deNavarre "The Chemistry and Manufacture of Cosmetics" Vol. Ill 2nd ed. 1975 Continental Press, Orlando, Florida USA. Materials such as urea and urea derivatives can also be used to form gels. In a mode which is designed to enhance the grease removal performance of the instant compositions, calcium ions, or, more preferably, a mixture of calcium and magnesium ions, are incorpor¬ ated into the gel. Levels of calcium or mixed calcium/magnesium ions up to about 2%, typically from about 0.4% to about 1.5%, provide superior grease removal in a hand dishwashing operation. Ratios of Ca:Mg of from about 5:1 to about 1:5, are preferably used. In one mode, the gel is prepared using a calcium salt and the magnesium form of an adjunct surfactant such as an alkyl ethoxy sulfate surfactant. Alternatively, water-soluble calcium and magnesium salts such as the halides, sulfates, hydroxides, and the like, can be used.
The incorporation of calcium and magnesium cations in the gels of this invention enhances cleaning performance, especially with regard to greasy soils of the type typically encountered in dishwashing operations. Unfortunately, the presence of ionic ingredients does tend to decrease gel viscosity. For lower viscosity gels herein (500,000-1,500,000 cps) the addition of common magnesium salts such as magnesium chloride, magnesium
sulfate, magnesium formate, magnesium citrate, and the like can also be used to selectively control final product viscosity. For gels of higher viscosity (above about 2,000,000 cps) such magnesium salts disrupt the desired physical properties and such common magnesium salts are preferably not used above about 0.3% levels. In order to overcome this problem and to allow the formulator to incorporate magnesium cations at levels of about 0.5% and greater, generally up to about 2%, typically 0.5%-1.5%, in the finished gels, it is preferred to add at least some of the magnesium in the form of the magnesium salt of the anionic surfactant. Stated otherwise, all of the magnesium cations can be added as the magnesium form of the surfactant, or part can come from the magnesium surfactant and part from other magnesium salts, as noted above. The magnesium form of the alkyl alkoxy sulfate surfactant can be generated i situ by combining Mg(0H)2 with the acid form of the surfactant during the mixing step herein. In an alternate mode, the use of other surfactants such as the Ci6 dimethyl amine oxides and/or C12-14 betaine surfactants will assist in the performance of magnesium-containing gels. EXAMPLE III
Gel compositions are as follows.
To 0.8 grams of magnesium sulfate, 0.8 grams of Ca formate and 6.7 grams of cocoamido propyl betaine (30% active, Albright- Wilson, United Kingdom) dissolved in 25 grams of water, 8 grams of C91-8T Dobanol (100% active, Shell, USA), 1.00 grams of boric acid and 20 grams of urea (99% active, Fisher Scientific, USA) are added and mixed at 71-74'C. Once a homogeneous mixture is obtained, 8 grams of 97.6% active coconut N-methyl glucamide and 28 grams of sodium Cjς secondary (2,3) alkyl sulfate are added and agitation is continued. (Ingredients such as detersive enzymes can be added when the temperature of the liquid reaches about 35-40 * C.) The final liquid product forms a gel on cooling.
In an alternate mode, a gel is provided without urea. To a solution formed by dissolving 0.002 grams of blue dye in 42 grams of water at 62'C, 0.25 grams of MgSθ4, 0.25 grams of CaCl2, 0.50 grams of perfume and 35% of 50% coconutalkyl C12-C 4 N-methyl glucamide paste are added with agitation. Once all the materials are dissolved, 21 grams of an 80% sodium C12-14 secondary (2,3)
alkyl sulfate paste is added. The solution is stirred for an additional 30 minutes at 77'C. At about 40'C, 0.5 grams of a commercial detersive protease composition is added and stirring is continued. Once stirring is stopped, the viscous liquid quickly solidifies into a gel after cooling.
While the preferred compositions herein are in the form of stable, homogeneous liquids and gels, other forms such as bars, granules and the like are also provided.
EXAMPLE IV A laundry bar suitable for hand-washing soiled fabrics is prepared by standard extrusion processes and comprises the following:
Ingredient % (wt . )
Ci6 secondary (2,3) alkyl sulfate, Na 30 Ci2-14 N-methylglucamide 5
Sodium tripolyphosphate 7
Sodium pyrophosphate 7
Sodium carbonate 25
Zeolite A (0.1-10μ) 5 Coconut monoethanolamide 2
Polyacrylate (m.w. 1400) 0.2
Brightener, perfume 0.2
Protease 0.3 Ca SO4 1
Mg SO4 1
Filler* Bal ance
♦ Can be selected from convenient materials such as CaCOβ, talc, clay, silicates, and the like.
In general terms, particulate detergent compositions compris¬ ing the secondary (2,3) alkyl sulfate surfactants can be prepared using a variety of well-known processes. For example, particles can be formed by agglomeration, wherein solids (including the secondary (2,3) alkyl sulfates) are forced/hurled together by physical mixing and held together by a binder. Suitable apparatus for agglomeration includes dry powder mixers, fluid beds and
turbilizers, available from manufacturers such as Lόdige, Eric, Bepex and Aeromatic.
In another mode, particles can be formed by extrusion. In this method, solids such as the secondary (2,3) alkyl sulfates are forced together by pumping a damp powder at relatively high pressures and high energy inputs through small holes in a die plate. This process results in rod like particles which can be divided into any desired particle size. Apparatus includes axial or radial extruders such as those available from Fuji, Bepex and Teledyne/Readco.
In yet another mode, particles can be formed by prilling. In this method, a liquid mixture containing the desired ingredients (i.e., one of them being secondary (2,3) alkyl sulfate particles) is pumped under high pressure and sprayed into cool air. As the liquid droplets cool they become more solid and thus the particles are formed. The solidification can occur due to the phase change of a molten binder to a solid or through hydration of free mois¬ ture into crystalline bound moisture by some hydratable material in the original liquid mixture. In still another mode, particles can be formed by compaction. This method is similar to tablet formation processes, wherein solids (i.e., secondary [2,3] alkyl sulfate particles) are forced together by compressing the powder feed into a die/mold on rollers or flat sheets. In another mode, particles can be formed by melt/solidifica¬ tion. In this method, particles are formed by melting the second¬ ary (2,3) alkyl sulfate with any desired additional ingredient and allowing the melt to cool, e.g., in a mold or as droplets.
Binders can optionally be used in the foregoing methods to enhance particle integrity and strength. Water, alone, is an operative binder with secondary (2,3) alkyl sulfates, since it will dissolve some of the secondary (2,3) alkyl sulfate to provide a binding function. Other binders include, for example, starches, polyacrylates, carboxymethylcellulose and the like. Binders are well-known in the particle making literature. If used, binders are typically employed at levels of 0.1%-5% by weight of the finished particles.
If desired, fillers such as hydratable and nonhydratable salts, crystalline and glassy solids, various detersive ingredi¬ ents such as zeolites and the like, can be incorporated in the particles. If used, such fillers typically comprise up to about 20% by weight of the particles.
Particles prepared in the foregoing manner can be subse¬ quently dried or cooled to adjust their strength, physical proper¬ ties and final moisture content, according to the desires of the formulator. The preferred overall making process for particulate products herein involves three distinct Steps: (1) agglomeration of the ingredients to form the base formula, followed by; (2) admixing various ingredients with the agglomerates formed in Step (1) (e.g., percarbonate bleach, bleach activators, and the like); and optionally, but preferably, (3) spraying materials such as perfume onto the final mix.
The base formula is agglomerated as opposed to spray dried in order to prevent degradation of some of the heat sensitive surfactants. The resulting product is a high density (ranging from 600 g/liter - 800 g/liter) free flowing detergent mix that can be used in place of current spray dried laundry detergents.
With regard to the base Agglomeration (Step 1, above), this procedure is comprised of four Steps:
(A) preparing a surfactant paste using mixers such as the Readco Standard Sigma Mixer, T-Series;
(B) agglomerating powder components with the surfactant paste using mixers such as the Eirich Mixer, R-Series;
(C) drying the agglomerates, such as in a batch-type Aeromatic fluidized bed or a continuous type static or vibrating fluidized bed (NIR0, Bepex or Carrier
(D) coating the agglomerates using a mixer such as an Eirich Mixer, R-Series.
The following describes the Agglomeration Step in more detail.
Step A - Preparation of Surfactant Paste - The objective is to combine the surfactants and liquids in the compositions into a common mix in order to aid in surfactant solubilization and
agglomeration. In this Step, the surfactants and other liquid components in the composition are mixed together in a Sigma Mixer at 140'F (60'C) at about 40 rpm to about 75 rpm for a period of from 15 minutes to about 30 minutes to provide a paste having the general consistency of 20,000-40,000 centipoise. Once thoroughly mixed, the paste is stored at 140'F (60 * C) until agglomeration Step (B) is ready to be conducted. The ingredients used in this Step include surfactants, acrylate/maleic polymer (m.w. 70,000) and polyethylene glycol "PEG" 4000-8000. Step B - Agglomeration of Powders with Surfactant Paste - The purpose of this Step is to transform the base formula ingredients into flowable detergent particles having a medium particle size range of from about 300 microns to about 600 microns. In this Step, the powders (including materials such as zeolite, citrate, citric acid builder, layered silicate builder (as SKS-6), sodium carbonate, ethylenediaminedisuccinate, magnesium sulfate and optical brightener) are charged into the Eirich Mixer (R-Series) and mixed briefly (ca. 5 seconds - 10 seconds) at about 1500 rpm to about 3000 rpm in order to mix the various dry powders fully. The surfactant paste from Step A is then charged into the mixer and the mixing is continued at about 1500 rpm to about 3000 rpm for a period from about 1 minute to about 10 minutes, preferably 1-3 minutes, at ambient temperature. The mixing is stopped when coarse agglomerates (average particle size 800-1600 microns) are formed.
Step C - The purpose of this Step is to reduce the agglomer¬ ates' stickiness by removing/drying moisture and to aid in particle size reduction to the target particle size (in the median particle range from about 300 to about 600 microns, as measured by sieve analysis). In this Step, the wet agglomerates are charged into a fluidized bed at an air stream temperature of from about 41'C to about 60'C and dried to a final moisture content of the particles from about 4% to about 10%.
Step D - Coat Agglomerates and Add Free-Flow Aids - The objective in this Step is to achieve the final target particle size range of from about 300 microns to about 600 microns, and to admix materials which coat the agglomerates, reduce the caking/lumping tendency of the particles and help maintain
acceptable flowability. In this Step, the dried agglomerates from Step C are charged into the Eirich Mixer (R-Series) and mixed at a rate of about 1500 rpm to about 3000 rpm while adding 2-6% Zeolite A (median particle size 2-5/wn) during the mixing. The mixing is continued until the desired median particle size of from about 1200 to about 400 microns is achieved (typically from about 5 seconds to about 45 seconds). At this point, from about 0.1% to about 1.5% by weight of precipitated silica (average particle size 1-3 microns) is added as a flow aid and the mixing is stopped. The following illustrates a laundry detergent composition prepared in the foregoing manner.
% (wt.) in % (wt.) in final product agglomerate
Ci4-i5 alkyl sulfate, Na 5.8 6.8
Ci6 secondary (2,3) alkyl sulfate, Na 17.3 20.4
C12-C13 ethoxylated alcohol (E03) 4.7 5.5
C12-14 N-methylglucamide 4.7 5.5
Acrylate/maleate copolymer 6.2 7.3
Polyethylene glycol (4000) 1.4 1.7
Aluminosilicate (zeolite) 8.8 10.3
Sodium citrate 1.9 2.2
Citric acid/SKS-6l 11.5 13.5
Sodium carbonate 12.2 14.4
EDDS2 0.4 0.5
Mg sulfate 0.2 0.2
Ca sulfate 0.2 0.3
Optical brightener 0.1 0.1
Moisture 7.6 8.9
Silica 3 0.4 0.5
Balance (unreacted and Na S04) _J__6 1.9
Agglomerate total 85.0 100.0
Percarbonate, Na (400-600 microns) 7.8
Silicone/PEG antifoam 0.3
Finished product total 100.0 lCo-particle of citric acid and layered silicate (2.0 ratio)
3 Hydrophobic precipitated silica (trade name SIPERNAT D-ll)
-^Sodium nonanoyloxybenzene sulfonate
The following are additional, nonli iting examples of liquid compositions according to this invention.
Ingredient % (wt.)
C12 N-methyl glucamide 9.0
C12 ethoxy (1) sulfate 6.0 DAN 214 SAS (Shell) 6.0
2-methyl undecanoic acid 4.5
C12 ethoxy (3) carboxylate 4.5
Cn alcohol ethoxylate (9) 4.0
Ci2-14 amine oxide 2.0 Sodium cumene sulfonate 2.0
Mg++ (as MgC12) 0.1
Ca++ (as Ca formate) 0.4
KCL 0.5 Water Balance
EXAMPLE VII The C12 ethoxy(l)sulfate in Example VI is replaced by an equivalent amount of DAN 216 SAS (Shell).
While the foregoing examples illustrate the practice of this invention using the secondary (2,3) alkyl sulfate surfactants and other, mainly anionic, adjunct surfactants, such compositions can also optionally contain various adjunct cationic surfactants and mixtures of cationic and nonionic adjunct surfactants. Useful cationics include the Cio-Cis alkyl trimethylammon um halides, the Cio-Cis alkyl dimethyl (Ci-Cβ) hydroxyalkylammonium halides,
ClO"Cl8 choline esters, and the like. If used, such cationic surfactants can typically comprise from 1% to 15% by weight of the compositions herein.