DE69326073T2 - Stabilization of active ingredients sensitive to oxidation in detergent compositions containing percarbonate - Google Patents

Abstract

Granular laundry detergents are formulated with percarbonate bleach and oxidation-sensitive ingredients such as brighteners, enzymes, perfumes and the like. The storage stability of such compositions is improved by the presence of silicate. For example, the tendency of stilbene-type brighteners to form undesirable yellow shades in the presence of percarbonate is diminished by the incorporation of silicate materials into the granules.

Description

TECHNICAL AREA

The present invention relates to granular detergent compositions containing a percarbonate bleach and one or more oxidation sensitive ingredients such as fluorescent whitening agents, enzymes, perfumes, chelating agents and the like. The compositions are formulated not only to provide good cleaning performance and bleaching performance, but also to reduce or eliminate oxidation of such ingredients during storage of the compositions.

BACKGROUND OF THE INVENTION

Formulating modern granular laundry detergents without the use of phosphate builders and under various constraints regarding fabric safety and environmental impact is a significant challenge. The formulator is faced with the need to provide detergent compositions that will remove a wide variety of soils and stains from a variety of fabrics. Detergent compositions must function effectively over a wide range of washing temperatures. They must be storage stable over a wide range of temperatures and humidities. Granular detergents should desirably be free-flowing and easy to dispense in automatic equipment. They must not foam too much or too little. To be affordable, they must be formulated using economical, yet safe and effective ingredients. Consequently, considerable investment continues to be made in the search for new and improved detergent compositions.

Inorganic bleaches such as percarbonate offer potential advantages to the detergent formulator due to their inherent cleaning ability. Furthermore, percarbonate bleaches offer potential advantages over the commonly used perborate bleach in that they do not interact adversely with important new surfactants such as the polyhydroxy fatty acid amides. In addition, there is now some evidence that perborate bleaches can sometimes undesirably complex with and stabilize "polyol" stains such as the polyphenolic materials found in chocolate. Percarbonates do not suffer from this disadvantage. In addition, when properly formulated, particularly as discussed herein, percarbonate can provide superior dosing characteristics compared to perborate.

Another type of ingredient frequently incorporated into granular laundry detergents comprises the fluorescent whitening agents, more commonly referred to as "whitening agents" or "optical bleaches". Such agents do not provide a true "bleaching" and stain removal function by themselves, as is the case with percarbonate. Rather, such agents are designed to attach to (textile) fabrics, especially white fabrics, to subtly adjust the overall visual impression from an undesirable "bleached" tint to a "bluish" tint, which the customer perceives as an improvement in the whiteness and brightness of the washed textile.

Unfortunately, it has now been discovered that granular detergents containing the desirable percarbonate bleaching agent can undesirably cause yellowing of certain oxidation-sensitive optical brighteners. It has now been further discovered that this undesirable yellowing effect is particularly problematic with the commercially important class of stilbene brighteners.

Yet another type of ingredient frequently used in granular laundry detergents comprises the various classes of detersive enzymes, including proteases, amylases, lipases, cellulases and mixtures thereof. It has now been found that such enzymes can be completely or partially inactivated in percarbonate-containing detergent compositions. Likewise, it has now been further found that other oxidation-sensitive detergent ingredients such as perfumes, unsaturated organic substances such as oleic acid, oleate soaps and oleyl sulfate, fatty amine fabric softeners and surfactants, amino chelating agents and the like are all susceptible to oxidative degradation upon storage in the presence of percarbonate bleach.

Without wishing to be limited by theory, one can now hypothesize that even with so-called "stabilized" percarbonate, there will always be some leakage of H2O2 from the percarbonate into the rest of the product during storage. This peroxide leakage is exacerbated at higher storage temperatures and relative humidities that may be encountered in warehouses. In addition, it has now been found that if the presence of metal ions, e.g. copper and iron, is minimized, the "leaked" H2O2 can be relatively harmless to oxidation-sensitive components. However, if uncontrolled metal ions are present, they can apparently catalytically degrade the leaked H2O2 to oxygen radicals that can degrade oxidation-sensitive components.

The present invention has discovered that the inclusion of certain silicate materials in percarbonate-containing laundry detergent granules prepared as described herein minimizes the aforementioned degradation problems.

STATE OF THE ART

The use of brighteners for various purposes, including their use in laundry detergents, is discussed in the Encyclopedia of Chemical Technology, Kirk-Othmer, Volume 4, 3. Ed., pages 213-226, John Wiley & Sons 1978. Problems related to stability are listed on pages 222-223. EP-451 893; US-5 236 613; Japanese A-4 227 693; Japanese 63-62442 and Japanese KOKOKU 61-16319 relate to percarbonate bleaches. Detergent enzymes and/or enzyme stabilizers are described in US Patents 4 261 868, 3 600 619, 3 519 570 and European 0 199 405.

EP-A-567 140, DE-A-41 16 701 and FR-A-2226463 describe the use of stabilized percarbonate bleach in cleaning agents.

SUMMARY OF THE INVENTION

The present invention involves the use of a silicate material (particularly water-soluble silicate, but also magnesium silicate colloids) to reduce or eliminate the oxidative degradation of oxidation-sensitive ingredients in granular detergent compositions, particularly in laundry detergents containing a percarbonate bleach. Such oxidation-sensitive ingredients include optical brighteners, perfumes, enzymes, chelating agents, fabric softening compositions, various unsaturated materials and mixtures thereof, examples of which are described below or are known to detergent formulators.

In a preferred form, the finished granular compositions of the invention comprise from 0.04 to 15% by weight of one or more of the oxidation-sensitive ingredients in combination with a detergent composition, characterized in that the detergent composition comprises:

(a) 10 to 85% by weight of the composition of particles comprising:

(i) 5 to 80 wt.% of particles of a builder which is a member selected from the group comprising zeolite builders, carbonate builders, or mixtures thereof;

(ii) 2 to 15 wt.% of a silicate, most preferably a sodium silicate;

(iii) 5 to 60% by weight of particles of a detersive surfactant or mixtures of detersive surfactants;

(iv) 0 to 70 wt.% of particles of a water-soluble inorganic sulfate salt, wherein the sulfate salt is contaminated with not more than 60 ppm iron and not more than 5 ppm copper;

(v) 0.3 to 15% by weight of a complexing agent when the water-soluble sulfate salt is present in an amount of 1% or more in the particles;

(b) from 3 to 50% by weight of the composition of percarbonate bleach particles having an average particle size in the range of 500 µm to 1000 µm, with not more than 10% by weight of the percarbonate being particles smaller than 200 µm and not more than 10% by weight of the particles being larger than 1250 µm;

(c) 7.7 to 35% by weight of the composition of water-soluble sulfate particles, said particles being dry-mixed with particles (a) and (b), the sulfate particles are contaminated with not more than 40 ppm iron and not more than 5 ppm copper, the sulphate particles have an average particle size in the range of 250 µm to 1400 µm, not more than 25% by weight of the sulphate particles are larger than 1000 µm and not more than 2% of the particles are smaller than 250 µm; and

(d) optional additional components.

To obtain optimum overall product stability, the particles (a) should have a moisture content of not more than 13% by weight, most preferably less than 10% by weight. To obtain good flowability and good dispensing ability in automatic equipment, the particles (a) should have a moisture content of at least 2% by weight. If the particles (a) are prepared by spray drying, they should preferably have a moisture content of at least 7% by weight.

Preferred compositions herein are those wherein the particles (a) comprise a builder selected from the group comprising zeolites A, P, MAP, X, Y or mixtures thereof, sodium carbonate builders and mixtures thereof.

When the particles (a) also comprise more than 1% of an optional water-soluble sulfate component, they also typically contain a complexing agent, preferably selected from the group consisting of phosphonate, aminocarboxylate and polycarboxylate complexing agents and mixtures thereof, typically in amounts of from 0.3 to 4.0% by weight in the particles.

For storage stability, the particles of percarbonate bleach (b) may be coated, e.g. with a member selected from the group comprising water-soluble carbonate, water-soluble sulfate, water-soluble citrate, dehydrated or partially hydrated zeolite, water-soluble surfactants or mixtures thereof. Whether stabilized by such agents or not, the particles of percarbonate bleach preferably have an average size in the range of 500 µm to 1000 µm. For stability purposes, it is also preferred that percarbonate particles (b) have a moisture content of not higher than 1%, more preferably not higher than 0.5% by weight of the percarbonate particles.

When the product also contains dry-blended sulphate, it is preferred, in order to impart further stability to the percarbonate, that the particles of sulphate (c) have less than 25 ppm, preferably less than 5 ppm, iron and preferably have a mean particle size in the range of 450 µm to 800 µm.

In a preferred form, the moisture content of the total compositions described herein is not higher than 8% by weight.

All percentages, ratios and proportions herein are by weight unless otherwise indicated.

DETAILED DESCRIPTION OF THE INVENTION

The brightener component and typical formulations and the formulation components used therein are described below, but are not intended to be limiting.

Percarbonate Bleach - The percarbonate bleach used herein is the conventional percarbonate material available from suppliers such as Solvay, FMC, Tokai Denka and others. If desired, and to provide additional storage stability, the percarbonate particles can be coated or "dusted" with various materials such as sodium citrate, sodium carbonate, sodium sulfate, water soluble surfactants and mixtures thereof. In this way, a stabilized percarbonate bleach can comprise 2.5% by weight of 2.5:1 sodium carbonate:sodium sulfate, or it can comprise 5% citrate. A preferred percarbonate bleach is in the form of particles having an average particle size in the range of 500 µm to 1000 µm, with no more than 10% by weight of the percarbonate being particles smaller than 200 µm and no more than 10% by weight of the particles being larger than 1200 µm. Typical compositions comprise 5 to 25% by weight percarbonate bleach.

Silicate - The silicate stabilizer employed herein includes particularly the alkali metal silicates having a SiO2:Na2O ratio ("R") in the range of 1.6:1 to 3.2:1, although silicates outside this preferred range may be useful, even if not entirely optimal. The sodium form of the silicate is usually used, although the inclusion of magnesium can further enhance the stability of the overall compositions, as will be described in more detail below. It is also convenient to form the Mg silicate form in situ by adding in the same particles (for example, in the same slurry when preparing spray dried particles) the sodium silicate and a magnesium salt (magnesium sulfate or magnesium chloride, for example). Silicates suitable for use herein include sodium silicate 1.6R solution, sodium silicate 2.OR solids or sodium silicate 3.2R solids available from Hoechst or Akzo. The ratio of silicate:oxidation sensitive components being stabilized is at least 1:1.

Brighteners - Any optical brighteners known in the art that do not contain copper or iron species may be advantageously incorporated into the detergent compositions herein at levels typically from 0.04 to 1.2% by weight. Commercial optical brighteners that may be useful in the present invention can be divided into subgroups that include, but are not necessarily limited to, derivatives of stilbene, pyrazoline, coumarin, carboxylic acid, methine cyanines, dibenzothiphene-5,5-dioxide, azoles, 5- and 6-membered heterocycles, and other miscellaneous agents. Examples of such brighteners are described in "The Production and Application of Fluorescent Brightening Agents," M. Zahradnik, published by John Wiley & Sons, New York (1982).

Specific examples of optical brighteners that can be used in the present compositions are those identified in U.S. Patent 4,790,856, issued to Wixon on December 13, 1988. These brighteners include the PHORWHITE series of brighteners. lern of Verona. Other brighteners disclosed in this publication include: Tipopal® UNPA, Tipopal® CBS and Tipopal® 5BM (trade names); available from Ciba-Geigy; Arctic White® CC and Arctic White® CWD (trade names) available from Hilton-Davis, based in Italy; the 2-(4-styryl-phenyl)-2H-naphthol([1,2-d)]triazoles; 4,4'-bis-(1,2,3-triazol-2-yl)-stilbenes;4,4'-bis-(styryl)bisphenyls; and the aminocoumarins. Specific examples of these brighteners include 4-methyl-7-diethyl-amino-coumarin; 1,2-bis(benzimidazol-2-yl)ethylene; 1,3-diphenylphrazolines; 2,5-bis(benzoxazol-2-yl)thiophene; 2-styryl-naphth-[1,2-d]oxazole; and 2-(stilbene-4-yl)-2H-naphtho-[1,2-d]triazole; see also U.S. Patent 3,646,015, issued February 29, 1972 to Hamilton.

It will be understood that while the invention can be used with all of the above-mentioned classes of brighteners and mixtures thereof, it is of particular importance for use with stilbene-type brighteners due to their tendency to yellow in the presence of percarbonate bleach. The invention is particularly useful with disodium 4,4'- bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonate, available from Ciba-Geigy as Tipopal® DMS, and disodium 4,4'-bis(4,6-di-anilino-1,3,5-triazin-2-yl)amino-stilbene-2-disulfonate brighteners.

Enzymes - Enzymes can be included in the formulations herein for a wide variety of fabric laundering purposes including, for example, the removal of protein-based, carbohydrate-based or triglyceride-based stains, and for preventing the transfer of volatile dyes and for fabric restoration. The enzymes that are included include proteases, amylases, lipases, cellulases and peroxidases, and mixtures thereof. Other types of enzymes can also be included. These can be of any origin, such as plant, animal, bacterial, fungal or yeast. However, their selection will be determined by several factors, such as pH activity and/or stability optima, thermostability, stability to active detergents, builders, etc. In this regard, bacterial or fungal enzymes are preferred, such as bacterial amylases and proteases and fungal cellulases.

Enzymes are typically incorporated in amounts sufficient to provide up to about 5 mg, on a weight basis, more usually 0.01 mg to 3 mg, of active enzyme per gram of the composition. Stated another way, the compositions herein typically comprise from 0.001 to 5% by weight, preferably 0.01-1% by weight, of a commercial enzyme preparation. Protease enzymes are typically present in such commercial preparations in amounts sufficient to provide from 0.005 to 0.1 Anson Units (AU) of activity per gram of the composition.

Suitable examples of proteases are the subtilisins obtained from special strains of B. subtilis and B. licheniforms. Another useful protease is obtained from a strain of Bacillus, with a maximum activity over the pH range of 8-12, developed and sold by Novo Industries A/S under the registered trade name ESPERASE®. The production of this enzyme and analogous enzymes is described in the British patent No. 1,243,784 to Novo. Proteolytic enzymes suitable for the removal of protein-based stains that are commercially available include those sold under the trade names ALCALASE® and SAVINASE® by Novo Industries A/S (Denmark) and MAXATASE® (trade names) by International Bio-Synthetics, Inc. (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® (trade name), International Bio-Synthetics, Inc., and TERMAMYL® (trade name), Novo Industries.

The cellulases useful in the present invention include both bacterial and fungal cellulase. Preferably they have a pH optimum between 5 and 9.5. Suitable cellulases are described in US Patent 4,435,307, Barbesgoard et al., issued March 6, 1984, which describes fungal cellulase produced from Humicola insolens and Humicola strain DSM 1800, or a cellulase 212-producing fungus belonging to the genus Aeromonas, and a cellulase extracted from the hepatopancreas of a marine mollusk (Dolabella Auricula Solander). Suitable cellulases are also described in GB-A-2 075 028; GB-A-2 095 275; and DE-OS-2247 832.

Suitable lipase enzymes for use in detergents include those produced by microorganisms of the Pseudomonas group such as Pseudomonas stutzeri ATCC 19.154 as described in British Patent 1,372,034; see also the lipases in Japanese Patent Application 53-20487, which was opened for public inspection on February 24, 1978. This lipase is available from Amano Pharmceutical Co. Ltd., Nagoya, Japan under the trade name Lipase P "Amano®", hereinafter referred to as "Amano P®". Other commercial lipases include Amano®-CES, lipases from Chromobacter viscosum, e.g. Chromobacter viscosum var. lipolyticum NRRLB 3673®, commercially available from Toyo Jozo Co., Tagata, Japan; and other Chromobacter viscosum lipases from U.S. Biochemical Corp., U.S.A. and Disoynth Co., Netherlands, as well as lipases from Pseudomonas gladioli. The LIPOLASE® enzyme derived from Humicola lanuginosa, commercially available from Novo (see also EPO 341 947), is a preferred lipase for the application described 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 the transfer of dyes or pigments removed from substrates during washing operations to other substrates in the washing solution. Peroxidase enzymes are known in the art and include, for example, horseradish peroxidase, ligninase and haloperoxidase, such as chloro- and bromoperoxidase. Detergent compositions containing peroxidase are described, for example, in the International PCT application WO-89/099813, published October 19, 1989, by O. Kirk, assigned to Novo Industries A/S.

A wide range of enzyme materials and means for incorporating them into synthetic detergent granules are also described in U.S. Patent 3,553,139, issued January 5, 1971 to McCarty et al. Enzymes are further described in U.S. Patent 4,101,457, Place et al., issued July 18, 1978, and U.S. Patent 4,507,219, Hughes, issued March 26, 1985. Enzyme materials useful in detergent formulations are described in U.S. Patent 4,261,868, Hora et al., issued April 14, 1981. The stability of SAVINASE®, ENDO GLUCANASE® A, cellulases, amylases and lipases are all improved by the practice of the present invention.

Chelating Agents - The detergent compositions herein may also optionally contain one or more iron and/or manganese chelating agents, particularly when a sulfate salt is present. Typically, the total compositions may comprise from 0.1% to 10% by weight of such chelating agents. Such chelating agents may be selected from the group consisting of aminocarboxylates, aminophosphonates, polyfunctionally substituted aromatic chelating agents, and mixtures thereof, all of which are described in more detail below. Without wishing to be bound by theory, it is believed that the utility of these materials is due in part to their exceptional ability to remove iron and manganese ions from washing solutions by forming soluble chelate complexes.

Aminocarboxylates useful as optional chelating agents include ethylenediaminetetraacetates, N-hydroxyethylethylenediaminetriacetates, nitrilotriacetates, ethylenediaminetetrapropionates, triethylenetetraaminehexaacetates, diethylenetriaminepentaacetates, and ethanoldiglycines, alkali metal, ammonium and substituted ammonium salts therein, and mixtures there.

Aminophosphonates are also useful for use as chelating agents in the compositions of the invention when at least low levels of total phosphorus are permitted in detergent compositions and include ethylenediaminetetrakis (methylenephosphonates), nitrilotris (methylenephosphonates) and diethylenetriaminepentakis (methylenephosphonates) such as DEQUEST® (trade name) ("DTPMP"). Preferably, these aminophosphonates do not contain alkyl or alkenyl groups having more than about 6 carbon atoms. HEDP, 1-hydroxyethanediphosphonate, is useful and preferably combined with aminophosphonates or aminocarboxylates for use as described herein.

Polyfunctionally substituted aromatic chelating agents are also useful in the compositions herein; see U.S. Patent 3,812,044, issued May 21, 1974, to Connor et al.. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes, such as 1,2-dihydroxy-3,5-disulfobenzene.

A preferred biodegradable chelating agent for use herein is ethylenediamine disuccinate ("EDDS"), particularly the [S,S] form as described in U.S. Patent 4,704,233, November 3, 1987, to Harturan and Perkins.

Perfumes - With respect to perfume stability, the compositions herein exhibit improved stability with respect to perfume ingredients that are sensitive to oxidation, particularly aldehydes and ketones. Thus, perfumery ingredients such as the floral scents, the woody scents, the citrus scents and the musk scents and mixtures thereof, all comprising varying amounts of aldehyde and ketone components, are advantageously employed herein. Importantly, the common perfume "carriers" such as phthalates, particularly diethyl phthalate, are also stable in the present compositions. Perfumery ingredients and/or carriers typically comprise 0.01 to 2% of the present compositions.

Additional formulation components

The formulation ingredients used in addition to those disclosed above are described below.

Detergent builders - The compositions also contain various conventional builders, or optionally mixtures of builders, usually in proportions of 5 to 60 wt%. Such builders assist in the control of mineral hardness in wash liquors and assist in the removal of particulate soil from fabrics.

Aluminosilicate (zeolite) builders are quite useful in particles (a) herein and are of great importance in most currently marketed granular heavy-duty detergent compositions. Aluminosilicate builders include those of the empirical formula:

MZ(zAlO₂ · ySiO₂)

wherein M is sodium, potassium, ammonium or substituted ammonium, z is 0.5 to 2; and y is 1; said material having an ion exchange capacity of at least about 50 milligram equivalents of CaCO₃ hardness per gram of anhydrous aluminosilicate. Preferred aluminosilicates are zeolite builders of the formula:

Naz[(AlO2 )z(SiO2 )y] xH2 O

wherein z and y are integers of at least 6, the molar ratio of z to y is in the range of 1.0 to 0.5, and x is an integer of 15 to 264.

Useful aluminosilicate ion exchange materials are commercially available. These aluminosilicates may be crystalline or amorphous in structure and may be naturally occurring aluminosilicates or synthetically derived. A process for preparing aluminosilicate ion exchange materials is described 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), Zeolite X, Zeolite Y, and Zeolite MAP. In a particularly preferred embodiment, the crystalline aluminosilicate ion exchange material has the formula:

Na 12 [(AlO 2 ) 12 (SiO 2 ) 12 ] xH 2 O

where x is 20 to 30, especially 27. This material is known as zeolite A. Dehydrated (x = 0-10) zeolite A can also be used. Preferably the aluminosilicate has a particle size of 0.1-10 µm diameter. Mixtures of zeolites with organic builders such as citrate are also useful.

Examples of other silicate builders useful herein include the sodium layered silicates described in U.S. Patent 4,664,839, issued May 12, 1987 to H. P. Rieck. NaSKS-6 is the trade name for a crystalline layered silicate sold by Hoechst (often abbreviated herein as "SKS-6" (trade name)). Unlike zeolite builders, the NaSKS-6 silicate builder does not contain aluminum. NaSKS®-6 has the δ-Na₂SiO₅ morphology form of layered silicate. It can be prepared by methods such as those described in German DE-A-34 17 649 and DE-A-37 42 043. SKS-6 is a highly preferred layered silicate for the application described herein, but other such layered silicates such as those of the general formula NaMSixO2x+1 yH2O, where 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, may be used herein. Various other layered silicates from Hoechst include NaSKS-5®, NaSKS-7® and NaSKS-11® (trade names), such as the α, β and γ forms. As mentioned above, the δ-Na2SiO5 (NaSKS-6 form) is most preferred for the application described herein. Other silicates may also be useful, such as magnesium silicate, which can serve as a lump-forming agent in granular formulations, as a stabilizer for oxygen bleaches, and as a component of foam control systems. Blends of silicates, particularly layered silicates, with organic builders such as citrates are also useful.

Examples of carbonate builders are the alkaline earth and alkali metal carbonates as described in German Patent Application No. 2 321 001, published on Nov. 15, 1973. Typical examples include calcite and sodium carbonate.

In addition to the aforementioned zeolite, silicate or carbonate builders, the final compositions herein may also optionally comprise 2% to 20% of various organic detergency builders, including, but not limited to, a wide variety of polycarboxylate compounds. Such builders may be dry blended with the overall compositions, or, less preferably, may be incorporated into particles (a). As used herein, "polycarboxylate" refers to compounds having a plurality of carboxylate groups, preferably having at least 3 carboxylates. Polycarboxylate builders may generally be added to the composition in acid form, but may also be added in the form of a neutralized salt. When used 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 comprises the ether polycarboxylates, including oxydisuccinate, as described 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 hydroxypolycarboxylates, copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1,3,5-trihydroxybenzene-2,4,6-trisulfonic acid and carboxymethyloxysuccinic acid, the various alkali metal, ammonium and substituted ammonium salts of polyacetic acids such as ethylenediaminetetraacetic acid and nitrilotriacetic acid, and polycarboxylates such as mellitic acid, succinic acid, oxydisuccinic acid, polymaleic acid, benzene-1,3,5-tricarboxylic acid, carboxymethyloxysuccinic acid and soluble salts thereof.

Citrate builders, e.g. citric acid and soluble salts thereof (especially sodium salt) polycarboxylate builders are of particular importance due to their availability from renewable resources and their biodegradability. Citrates are often used in granular compositions in combination with zeolite and/or layered silicate builders. Oxydisuccinates are also useful in such compositions and combinations.

Also useful in the detergent compositions of the present invention are the 3,3-dicarboxy-4-oxa-1,6-hexanedioates and related compounds described in U.S. Patent 4,566,984, Bush, issued January 28, 1986. Useful succinic acid builders include C5 -C20 alkyl and alkenyl succinic acids and salts thereof. A particularly preferred compound of this type is dodecenyl succinic acid. Specific examples of succinate builders include lauryl succinate, myristyl succinate, palmityl succinate, 2-dodecenyl succinate (preferred), 2-pentadecenyl succinate, and the like. Lauryl succinates are the preferred builders of this group and are described in European patent application 86200690.5/0 200 263, published on November 5, 1986.

Other suitable polycarboxylates are described 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-C₁₈ monocarboxylic acids, may also be incorporated into the compositions alone or in combination with the aforementioned builders, particularly citrate and/or the succinate builders, to provide additional builder activity. Such use of fatty acids generally results in a reduction in foaming, which should be considered by the formulator.

Although it is not preferred in situations where phosphorus-based builders can be used, the various alkali metal phosphates such as the well-known sodium tripolyphosphates, sodium pyrophosphate and sodium orthophosphate can be used.

Detersive Surfactants - The compositions herein also contain various anionic surfactants, or optionally mixtures of anionics with nonionic, zwitterionic or semipolar surfactants, typically in amounts of 5 to 40% by weight.

Non-limiting examples of surfactants useful herein include the conventional C11-C18 alkylbenzenesulfonates ("LAS") and C10-C20 primary, branched chain and random alkyl sulfates ("AS"), the C10-C18 secondary (2,3) alkyl sulfates of the formula CH3(CH2)x(CHOSO3- M+)CH3 and CH₃(CH₂)y(CHOSO₃⁻M⁺)CH₂CH₃, where x and (y + 1) are integers of at least about 7, preferably at least about 9, and M is a water-solubilizing cation, especially sodium, the C₁₀-C₁₈alkyl alkoxy sulfates ("AEXS"; especially EO 1-5- ethoxy sulfates), the C₁₀-C₁₈alkyl alkoxy carboxylates (especially the EO 1-5- ethoxy carboxylates), the C₁₀-C₁₈ glycerol ethers, the C₁₀-C₁₈alkyl polyglycosides and their corresponding sulfated polyglycosides, and the α-sulfonated C12-C18 fatty acid esters. If desired, the conventional nonionic and amphoteric surfactants such as the C10-C18 alkyl ethoxylates ("AE") including the so-called narrow peak alkyl ethoxylates and C6-C12 alkylphenol alkoxylates (particularly ethoxylates and mixed ethoxy/propoxy), C12-C18 betaines and sulfobetaines ("sultaines"), C10-C18 amine oxides, and the like, may also be included in the overall compositions. The C₁₀-C₁₈-N-alkyl polyhydroxy fatty acid amides may also be used. Typical examples include the C₁₂-C₁₈-N-methylglucamides. Other conventionally useful surfactants are listed in the standard literature.

Sulfate Salts - The compositions herein most preferably comprise a water-soluble inorganic sulfate salt having the physical and chemical parameters described above. Typical examples of such salts include sodium sulfate, magnesium sulfate and aluminum sulfate. The compositions typically comprise 12 to 25 wt% sulfate.

Additional ingredients

The compositions herein may optionally include one or more other detergent additive materials or other materials to aid or enhance 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 but non-limiting examples of such materials.

Enzyme Stabilizers - The enzymes employed herein can be further stabilized by the presence of water-soluble sources of calcium and/or magnesium ions in the final compositions which provide such ions to the enzymes. Additional stability can be provided by the presence of various other stabilizers described in the art, particularly borate species: see Severson in U.S. Patent No. 4,537,706, cited above. Typical detergents 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 ions per kilogram of the final composition. This may vary somewhat depending on the amount of enzyme present and its response to the calcium or magnesium ions. The proportion of calcium or magnesium ions Magnesium ions should be selected so that some minimum amount is always present for the enzyme after complexation with builders, fatty acids, etc. in the composition has been allowed. Any water-soluble calcium or magnesium salt may be used as a source of calcium or magnesium ions, including, but not limited to, calcium chloride, calcium sulfate, calcium malate, calcium maleate, calcium hydroxide, calcium formate, and calcium acetate and the corresponding magnesium salts. A small amount of calcium ions, generally 0.05 to 0.4 mmoles per kilo, is also often present in the composition as a result of the calcium in the enzyme slurry and formula water. In granular detergent compositions, the formulation may include a sufficient amount of a water-soluble calcium ion source to provide such amounts in the laundry liquor. Alternatively, natural water hardness may suffice.

It is understood that the foregoing levels of calcium and/or magnesium ions are sufficient to provide enzyme stability. Additional calcium and/or magnesium ions may be added to the compositions to provide an additional level of grease removal performance. Accordingly, the compositions herein may comprise from 0.05 to 2% by weight of a water-soluble source of calcium or magnesium ions, or both. The amount may, of course, vary with the amount and type of enzyme used in the composition.

The compositions herein may also optionally, but preferably, contain various additional stabilizers, particularly borate-type stabilizers. Typically, such stabilizers are used in the compositions in amounts of from 0.25 to 10%, preferably from 0.5 to 5%, more preferably from 0.75 to 3% by weight of boric acid or other borate compounds capable of forming boric acid in the composition (calculated on a boric acid basis). 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, butaneboronic acid and p-bromophenylboronic acid) may also be used in place of boric acid.

Bleach Activators - The detergent compositions herein may optionally include bleaching agents or bleaching compositions containing a bleaching agent and one or more bleach activators. If present, the amount of bleach activators is typically in the range 0.1% to 60%, more usually in the range 0.5% to 40%, of the bleaching composition containing the percarbonate bleach plus bleach activator.

The percarbonates are preferably used in the presence of bleach activators which result in the in situ formation in aqueous solution (i.e. during the washing process) of the peroxyacid corresponding to the bleach activator. Various non-limiting examples of activators are described in U.S. Patent 4,915,854, issued April 10, 1990 to Mao et al., and U.S. Patent 4,412,934. The nonanoyloxybenzenesulfonate (MOBS) and tetraacetylethylenediamine (TAED) activators are typical, and mixtures thereof may also be used. Benzoyl caprolactam and benzoyloxybenzene sulfonate activators may also be used; see also US-4,634,551 for other typical bleaching agents and activators useful herein.

Bleaching agents other than percarbonate bleaching agents are known in the art and may optionally be employed herein. One type of non-oxygen bleaching agent of particular interest includes photoactivated 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. When employed, detergent compositions typically contain from 0.025 to 1.25% by weight of such photoactivated bleaching agents, particularly sulfonated zinc phthalocyanine.

Polymeric soil release agent - Any soil release agent known to those skilled in the art may optionally be used in the compositions and methods of the 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 on hydrophobic fibers and remain there until the completion of the wash and rinse cycles, thereby serving as an anchor for the hydrophilic segments. This may allow stains occurring following treatment with the soil release agent to be more easily cleaned in subsequent laundering procedures.

The polymeric soil release agents useful herein include, in particular, those soil release agents comprising: (a) one or more nonionic hydrophilic components consisting essentially of (i) polyoxyethylene segments having a degree of polymerization of at least 2, or (ii) oxypropylene or polyoxypropylene segments having a degree of polymerization of from 2 to 10, wherein the hydrophilic segment does not comprise an oxypropylene unit unless it is linked to the adjacent units at each end by ether linkages, or (iii) a mixture of oxyalkylene units comprising oxyethylene and from 1 to 30 oxypropylene units, wherein the mixture contains a sufficient amount of oxyethylene units such that the hydrophilic component has a hydrophilicity great enough to increase the hydrophilicity of conventional synthetic polyester fiber surfaces upon attachment of the soil release agent to such a surface, wherein the hydrophilic segments preferably comprise at least about 25% oxyethylene units, and more preferably, particularly for those components having 20 to 30 oxypropylene units, at least about 50% oxyethylene units; or (b) one or more hydrophobic components comprising (i) C₃ oxyalkylene terephthalate segments; wherein the ratio of oxyethylene terephthalate: C₃ oxyalkylene terephthalate units is about 2:1 or less if the hydrophobic components also comprise oxyethylene terephthalate, (ii) C₄-C₆ alkylene or oxy-C₄-C₆ alkylene segments, or mixtures thereof, (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 thereof therein, wherein the substituents are in the form of C₁-C₄ alkyl ether or C₄ hydroxyalkyl ether cellulose derivatives or mixtures therein, and such cellulose derivatives are amphiphilic, thereby having a sufficient amount of C₁-C₄ alkyl ether and/or C₄ hydroxyalkyl ether moieties to deposit on conventional synthetic polyester fiber surfaces and to retain a sufficient amount of hydroxyls after being adhered to such conventional synthetic fiber surfaces to increase fiber surface hydrophilicity, or a combination of (a) and (b).

Typically, the polyoxyethylene segments of (a)(i) have a degree of polymerization of from 2 to 200, although higher amounts may be employed, preferably from 3 to 150, more preferably from 6 to 100. Suitable hydrophobic oxy-C4-C6 alkylene segments include, but are not limited to, end caps of polymeric soil release agents such as MO3S(CH2)nOCH2CH2O-, where M is sodium and n is an integer from 4-6, as described 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 cellulose 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 METHOCEL® (trade name) (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 hydrophobic poly(vinyl ester) segments include graft copolymers of poly(vinyl ester), e.g. C1-C6 vinyl ester, 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 type include the SOKALAN® type of material (trade name), e.g. SOKALAN® HP-22 (trade name), available from BASF (Germany).

One type of soil release agent is a random block copolymer of ethylene terephthalate and polyethylene oxide (PEO) terephthalate. The molecular weight of this polymeric soil release agent ranges 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 polymeric soil release agent is polyester having repeat units of ethylene terephthalate units containing 10-15 wt.% ethylene terephthalate units together with 90-80 wt.% polyoxyethylene terephthalate units derived from a polyoxyethylene glycol having an average molecular weight of 300-5000. Examples of this polymer include the commercially available material ZELCON® 5126 (trade name) (from Dupont) and MILEASE® T (from ICl); see also U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.

Another polymeric soil release agent is a sulfonated product of a substantially linear ester oligomer consisting of an oligomeric ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and terminal units covalently bonded to the backbone. These soil release agents are fully described 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 oligomeric anionic end-capped esters of U.S. Patent 4,721,580, issued January 26, 1988 to Gosselink, and the oligomeric block polyester compounds of U.S. Patent 4,702,857, issued October 27, 1987 to Gosselink.

Still other 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 describes terephthalate esters, particularly sulfoaryl, with anionic end caps.

If used, soil release agents generally comprise from 0.01% to 10.0% by weight of the detergent compositions herein, typically from 0.1% to 5%, preferably from 0.2% to 3.0%.

Clay Soil Removal/Anti-Redeposition Agents - The compositions of the present invention may also optionally contain water-soluble ethoxylated amines having clay soil removal and anti-redeposition properties. Granular detergent compositions containing such agents contain from 0.01 to 10.0% by weight of the water-soluble ethoxylated amines.

The most preferred clay soil removal and antiredeposition 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 described in European Patent Application 111,965, Oh and Gosselink, published June 27, 1984. Other clay soil removal/antiredeposition agents that may be employed include the ethoxylated amine polymers described in European Patent Application 111,984, Gosselink, published June 27, 1984; the zwitterionic polymers described in European Patent Application 112,592, Gosselink, published July 4, 1984; and the amine oxides described in U.S. Patent 4,548,744, Connor, issued October 22, 1985. Other clay soil removal and/or antiredeposition agents known in the art may also be used in the compositions herein. Another type of preferred antiredeposition agent includes the carboxymethyl cellulose (CMC) materials. These materials are well known in the art.

Polymeric Dispersants - Polymeric dispersants may be advantageously used at levels of 0.1 to 7% by weight in the compositions herein, particularly in the presence of zeolite and/or layered silicate builders. Suitable polymeric dispersants include polymeric polycarboxylates and polyethylene glycols, although others known in the art may also be used. Without wishing to be limited by theory, it is believed that polymeric dispersants enhance overall detergent builder performance when used in combination with other builders (including the lower molecular weight polycarboxylates) to provide crystal growth inhibition, particle soil release peptization and antiredeposition.

Polymeric polycarboxylate materials can be prepared by polymerizing or copolymerizing suitable unsaturated monomers, preferably in their acid form. Unsaturated monomeric acids which can be polymerized to form suitable polymeric polycarboxylates include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid, and methylenemalonic acid. The presence in the polymeric polycarboxylates herein of monomeric segments which do not contain carboxylate residues, such as vinyl methyl ether, styrene, ethylene, etc., is useful, provided that such segments do not constitute more than about 40% by weight.

Particularly suitable polymeric polycarboxylates may be derived from acrylic acid. Such acrylic acid-based polymers useful herein are the water-soluble salts of polymerized acrylic acid. The average molecular weight of such polymers in the acid form is preferably in the range of 2,000 to 10,000, more preferably 4,000 to 7,000, and most preferably 4,000 to 5,000. Water-soluble salts of such acrylic acid polymers may include, for example, the alkali metal, ammonium, and substituted ammonium salts. Soluble polymers of this type are known materials. The use of polyacrylates of this type in detergent compositions has been described, for example, in Diehl, U.S. Patent 3,308,067, issued March 7, 1967.

Acrylic acid/maleic acid based copolymers may also be used as a preferred component of the dispersant/antiredeposition agent. Such materials include the water-soluble salts of copolymers of acrylic acid and maleic acid. The average molecular weight of such copolymers in acid form is preferably in the range of 2,000 to 100,000, more preferably 5,000 to 75,000, most preferably 7,000 to 70,000. The ratio of acrylate to maleate segments in such copolymers is generally in the range of 30:1 to 1:1, more preferably 10:1 to 2:1. Water-soluble salts of such acrylic acid/maleic acid copolymers may include, for example, the alkali metal, ammonium and substituted ammonium salts. Soluble acrylate/maleate copolymers of this type are known materials described in European Patent Application No. 66915, published on December 15, 1982.

Another polymeric material that can be included is polyethylene glycol (PEG). PEG can exhibit dispersant performance as well as act as a clay soil remover deposition/antiredeposition agents. Typical molecular weight ranges for these purposes are 500 to 100,000, preferably 1,000 to 50,000, more preferably 1,500 to 10,000.

Polyaspartate and polyglutamate dispersants (molecular weight 10,000) can also be used, especially in conjunction with zeolite builders.

It will be understood that the present invention, while applicable to all of the above-mentioned classes of brighteners and mixtures thereof, is of particular significance for use with stilbene-type brighteners, particularly distilbene brighteners, due to their tendency to yellow in the presence of percarbonate.

Suds Suppressors - Compounds to reduce or suppress the formation of suds can be incorporated into the compositions of the present invention. Suds suppression may be of particular interest under conditions such as those found in the front loading European style laundry washing machines or in the concentrated wash process of U.S. Patents 4,489,455 and 4,489,574, or when the detergent compositions herein optionally include a relatively high sudsing surfactant additive.

A wide variety of materials can 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 suppressors of particular interest includes monocarboxylic fatty acids and salts soluble 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 suppressors typically have hydrocarbon chains of from 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.g., fatty acid triglycerides), fatty acid esters of monohydric alcohols, C18-C40 aliphatic ketones (e.g., stearone), etc. Other suds inhibitors include N-alkylated aminotriazines such as tri- to hexaalkylmelamines or di- to tetraalkyldiaminechlorotriazines formed as products of cyanuric chloride with two or three moles of primary or secondary amine having 1 to 24 carbon atoms, propylene oxide, and monostearyl phosphates such as monostearyl alcohol phosphate esters and monostearyl dikali metal (e.g., K, Na, and Li) phosphates and phosphate esters. Hydrocarbons such as paraffin and haloparaffin can be used in liquid form. Liquid hydrocarbons are liquid at room temperature and atmospheric pressure and have a pour point in the range of -40ºC and 5ºC, as well as a minimum boiling point of not less than 110ºC (atmospheric pressure). The use of waxy hydrocarbons is also known, which preferably have a melting point of less than 100ºC. Hydrocarbons are a preferred category of suds suppressors for detergent compositions. Hydrocarbon suds suppressors are described, for example, in U.S. Patent 4,265,779, issued May 5, 1981 to Gandolfo et al. The hydrocarbons thus include aliphatic, alicyclic, aromatic and heterocyclic saturated or unsaturated hydrocarbons having from 12 to 70 carbon atoms. The term "paraffin" as used herein 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, where the polyorganosiloxane is chemically adsorbed or fused to the silica. Silicone suds suppressors are well known in the art and are described, for example, 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 described in U.S. Patent 3,455,839, which relates to compositions and methods for defoaming aqueous solutions by incorporating therein small amounts of polydimethylsiloxane fluids.

Mixtures of silicone and silanized silica are described, for example, in German patent application DOS 2 124 526. Silicone defoamers and foam control agents in granular detergent compositions are described 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 foam control agent consisting essentially of:

(i) polydimethylsiloxane fluid having a viscosity of 20 cs. to 1500 cs. at 25ºC;

(ii) 5 to 50 parts per 100 parts by weight of (i) a siloxane resin consisting of (CH₃)₃ SiO1/2 units of SiO₂ units in a ratio of (CH₃)₃ SiO1/2 units and to SiO₂ units of 0.6:1 to 1.2:1; and

(iii) 1 to 20 parts per 100 parts by weight of (i) a solid silica gel.

In the preferred silicone suds suppressor used herein, the solvent for a continuous phase is certain polyethylene glycols or polyethylene-polypropylene glycol copolymers or mixtures thereof (preferred), and not polypropylene glycol. The primary silicone suds suppressor is branched chain/crosslinked and non- linear.

To further illustrate this point, typical controlled suds laundry detergent compositions optionally comprise from 0.001 to 1, preferably from 0.01 to 0.7, most preferably from 0.05 to 0.5, weight percent of the silicone suds suppressor which (1) has a non aqueous emulsion of a primary antifoam agent which is a mixture of (a) a polyorganosiloxane, (b) a resinous siloxane or a silicone resin-forming silicone compound, (c) a finely divided filler material and (d) a catalyst for accelerating the reaction of the 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 greater than 2% by 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., column 1, line 46, through column 4, line 35.

The silicone suds suppressor herein preferably comprises polyethylene glycol and a copolymer of polyethylene glycol/polypropylene glycol, all of which have an average molecular weight of less than 1000, preferably between 100 and 800. The polyethylene glycol and polyethylene/polypropylene copolymers herein have a solubility in water at room temperature of greater than 2% by weight, preferably greater than 5% by weight.

The preferred solvent herein is polyethylene glycol having an average molecular weight of less than 1000, more preferably between 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 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, especially with a molecular weight of 4000. They also preferably do not contain block copolymers of ethylene oxide and propylene oxide, such as PLURONIC® L101 (trade name).

Other suds suppressors useful herein include the secondary alcohols (e.g., 2-alkyl alkanols) and mixtures of such alcohols with silicone oils, such as the silicones described in US 4,798,679, 4,075,118 and EP 150 872. The secondary alcohols include the C6-C16 alkyl alcohols having a C1-C16 chain. A preferred alcohol is 2-butyloctanol, available from Condea under the trade name ISOFOL 12. Mixtures of secondary alcohols are available from Enichem under the trade name ISALCHEM 123. Mixed suds suppressors typically comprise mixtures of alcohol + silicone in a weight ratio of 1:5 to 5:1.

For detergent compositions used in automatic laundry washing machines, foam should not be formed to the extent that it overflows in the washing machine. Such foam suppressors, when used, are present in a "foam suppression amount". By "foam suppression amount" is meant that the formulator of the composition can select an amount of such foam control agent which is sufficient controls the foam, resulting in a low foaming laundry detergent for use in automatic laundry washing machines. The compositions herein generally comprise from 0% to 5% of the foam suppressor. When used as a foam suppressor, monocarboxylic fatty acids and salts therein are typically present in amounts up to 5% by weight of the detergent composition. Preferably, from 0.5% to 3% fatty monocarboxylate foam suppressor is used. Silicone foam suppressors are typically used in amounts up to 2.0% by weight of the detergent composition, although higher amounts can be used. This upper limit is practical in nature, primarily due to concerns about cost minimization and the effectiveness of lower amounts for effective foam control. Preferably, from 0.01% to 1% of silicone foam suppressor is used, more preferably from 0.25% to 0.5%. As used herein, these weight percent values include any silica that may be used in combination with the polyorganosiloxane, as well as any additive materials that may be employed. Monostearyl phosphate suds suppressors are generally used in amounts ranging from 0.1% to 2% by weight of the composition. Hydrocarbon suds suppressors are typically used in amounts ranging from 0.01% to 5.0%, although higher levels may be used. The alcohol suds suppressors are typically used at 0.2-3% by weight of the final compositions.

In addition to the aforementioned ingredients, the compositions herein may also be used with a variety of other additional ingredients which provide other benefits in various compositions within the scope of the invention. A variety of such additional ingredients are discussed below, without any limitation being intended.

Fabric Softeners - Various wash-added fabric softeners, particularly the very fine smectic clays or soap clays of U.S. Patent 4,062,647, Storm and Nirschl, issued December 13, 1977, as well as other softening clays known in the art, may optionally be used in the present compositions, typically at levels of 0.5 to 10 weight percent, to provide fabric softening benefits concurrently with fabric cleaning. Clay softeners may be used in combination with amine and cationic softeners, such as described 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. Mixtures of cellulase enzymes (e.g. CAREZYME® (trade name) (Novo) and clays are also useful as high performance fabric softeners. Various cationic materials can be added to improve static control.

Other Ingredients - A wide variety of other ingredients useful in the detergent compositions can be included in the compositions herein, including other active ingredients, carriers, processing aids, dyes or pigments, etc. When high foaming is desired, foaming agents depressants such as the C₁₀-C₁₆ alkanolamides are included in the compositions, typically at levels of 1% to 10%. The C₁₀-C₁₄ monoethanol and diethanolamides illustrate a typical class of such foam boosters. The use of such foam boosters with high foaming surfactant additives such as the above-mentioned amine oxides, betaines and sultaines is also advantageous. If desired, soluble magnesium salts such as MgCl₂, MgSO₄ and the like can be added at levels typically 0.1%-2% to provide additional foaming and/or stability as mentioned below.

Various cleaning ingredients used in the present compositions can optionally be further stabilized by absorbing the ingredients onto a porous hydrophobic substrate and then coating the substrate with a hydrophobic coating. Preferably, the cleaning ingredient is mixed with a surfactant before being absorbed into the porous substrate. Upon use, the cleaning ingredient is released from the substrate into the aqueous wash liquor where it performs the desired cleaning function.

To explain this process in more detail, porous hydrophobic silica (trade name SIPERNAT® D10, DeGussa) is mixed with a proteolytic enzyme solution containing 3% to 5% of ethoxylated nonionic C13-15 alcohol EO(7) surfactant. Typically, the enzyme/surfactant solution is 2.5 times 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 resulting silicone oil dispersion is emulsified or otherwise added to the final detergent matrix. By means of these methods, ingredients such as the aforementioned enzymes, bleaches, bleach activators, bleach catalysts, photoactivators, dyes, fluorescers, fabric conditioners and hydrolysable surfactants can be "protected" for use in cleaning agents, including liquid laundry detergent compositions.

Manufacturing equipment

As described above, the granular compositions of the invention are conveniently and preferably prepared using three types of particles, designated for convenience as (a), (b) and (c). The following explains the preparation of such preferred compositions. However, it is recognized that other methods of combining the detergent ingredients may be used without departing from the spirit and scope of the invention.

Various methods and equipment are available to prepare the particles (a) for use in granular detergent compositions according to the present invention. (The particles (b) and (c) can be prepared by conventional grinding and agglomeration techniques). Current commercial practice in the art involves mixing the various ingredients in an aqueous medium (the so-called "soap mix"), followed by passage through a heated spray drying tower to form granular particles such as (a) which often have a density of less than 550 g/l. When particles of such low density are desired, the spray dryer is an acceptable means for their preparation. When high density particles (above 550 g/L, preferably 650-900 g/L) are desired, and when the spray dryer is used as part of the overall process described herein, the resulting spray dried particles can be further densified, such as by use of the facilities and equipment described below. In the alternative, the formulator can eliminate the spray dryer by use of mixing, compacting and granulation equipment which is commercially available. A non-limiting description of such equipment for use described herein follows.

High speed mixer/densifiers can be used in the present process to produce high density particles. For example, the device sold under the trade name "Lödige® CB30" Recycler comprises a static cylindrical mixing drum with a central rotating shaft with mixing/cutting blades mounted thereon. In use, the ingredients for the total detergent composition are fed into the drum and the shaft/blade assembly rotates at speeds in the range 100-2500 rpm to provide thorough mixing/densification. Other such devices include the devices sold under the trade name "Shugi Granulator" and under the trade name "Drais® K-TTP 80.

Depending on the degree of compaction and/or agglomeration desired, a processing step involving further compaction may be carried out. Equipment such as that sold under the trade name "Lödige® KM600 Mixer" (trade name), also known as the "Lödige® Ploughshare Mixer", may be used. Such equipment is typically operated at 40-160 rpm. Other useful equipment includes the equipment available under the trade name "Drais® K-T 160". The Lödige CB or KM type equipment may be used alone or sequentially, e.g. using the CB for paste dispersion and the KM for agglomeration. Batch or continuous feeding may be used.

In yet another procedure, the particles (a) of the invention may be prepared using a fluid bed mixer. In this method, the various ingredients are combined in an aqueous slurry and sprayed into a fluid bed of particles comprising, for example, particles of a zeolite or layered silicate or carbonate builder to provide the particles (a). In an alternative procedure, the slurry may be sprayed into a fluid bed of zeolite or layered silicate particles plus particles of a surfactant. In such a process, the first step may optionally involve mixing the slurry using a "Lödige® CB30" or "Flexomix® 160" (trade name), available from Shugi. Fluidized or moving beds of the type available under the trade name "Escher Wyss" may be used in such processes. Other types of granule making apparatus useful herein include the apparatus described in U.S. Patent 2,306,898 to G. L. Heller, December 29, 1942.

Whichever method is used, the particles (a) are combined with percarbonate particles (b) and sulfate particles (c), suitably by dry mixing. Any additives, perfumes, etc. can be mixed in or sprayed onto the mixture of the three types of particles.

The ultimate density of the particles and compositions herein can be measured by a variety of simple techniques, usually involving metering a quantity of the granular material into a container of known volume, determining the weight of the material, and reporting the density as grams/liter. Techniques used herein allow the material to flow into the measuring container under gravity, and without pressure or other compaction in the measuring container. Density measurements should be made at room temperature. The granular material whose density is being measured should be at least 24 hours old before testing and should be kept at room temperature for 24 hours. Relative humidity is not particularly critical, but should not be so high that the particles stick together. A relative humidity of 50% or less is convenient. Of course, lumps in the material should be gently broken up before testing is performed. In a typical method, the sample of material is allowed to flow through a funnel mounted on a hopper (#150; Seedburo Equipment Company, Chicago, Illinois) into an Ohaus cup of known volume and weight (#104; Seedburo) and stand. The top of the cup is positioned about 50 mm from the bottom of the funnel, and the cup is filled to overflowing. A spatula or other smooth edge is then scraped across the top of the cup, without vibration or tapping, to level the material, filling the cup accurately and completely. The weight of material in the cup is then measured. The density can be reported as g/L, or ounces/cubic inch. Repeat runs are made and reported as an average. The relative error is about 0.4%.

The detergent compositions herein are preferably formulated so that, during use in aqueous cleaning operations, the wash water has a pH of between 6.5 and 11, preferably between 7.5 and 10.5. Techniques for regulating the pH at recommended use levels include the use of buffers, alkalis, acids, etc., and are well known to those skilled in the art.

The following Examples A and B illustrate granular detergent compositions according to the invention. EXAMPLE I

* % by weight, based on the total composition.

¹ Corresponds to 10.6% moisture in the spray dried granule component, with the component representing 47% of the final composition.

*** Percarbonate coated with 2.5% of a carbonate/sulfate mixture (2.5:1 weight ratio) with an activity of 13.25% (Average Oxygen (AvOx) content), with an average particle size of 600 µm.

** Na sulfate with 3 ppm iron, 1 ppm copper, 1% particles less than 250 um, 10 particles less than 425 um, 60% particles less than 600 um, 70% particles below 850 um, 90º10 particles less than 1000 um.

The oxidation-sensitive ingredient, such as the brightener, can be added to the product in any desired proportion in any convenient manner, such as by inclusion in the spray-dried mixture, by addition to the product as a powder, or by spraying onto the product alone (e.g., the perfume) or in a nonionic ethoxylated (AE) surfactant. With respect to brightener stability, measurement of brightener discoloration can be done by visual inspection of the stored white granules (a distinct yellow color develops) or in a more quantitative manner by standard photometric methods, e.g., Hunter White. As can be seen from the results below, brightener discoloration to yellow is significantly reduced by the compositions herein. The data demonstrate improved brightener color stability for granular composition A of Example I vs. various test products using Tinopal® DMS brightener (disodium 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonate). The following results are obtained with the Rufheller, which is sprayed and dried simultaneously with zeolite, silicate and surfactants.

Results (Hunter color measurement) Blue/Yellow Index Test composition (+ ve = g elbz -ve = blue)

Fresh product -4.20

4 weeks storage (90ºF (32ºC); 80% relative humidity), closed carton

a) Product - Percarbonate (includes "crushed" silicate) -4.09

b) Commercial granular product (ARIEL) plus percarbonate/no silicate 0.75

After 4 weeks storage at 40ºC in a closed box

c) Fresh product - 4.20

d) Product with percarbonate (includes "crushed" silicate) -3.92

e) Product with percarbonate (no "crushed" silicate) +1.67

In a modification of the foregoing, the stabilizing benefits of the silicate are further enhanced by the addition of soluble magnesium salts such as MgCl2 or MgSO4 to the spray dried particles (a), conveniently in the soap mixer. Without wishing to be limited by theory, it is hypothesized that the Mg/silicate colloids formed in the soap mixer would be highly scavenging of heavy metal cations. Magnesium salt:silicate ratios as low as 0.2:3.0 are effective.

The moisture in the above compositions can be determined by any conventional means. In a preferred simple method, the moisture is measured as moisture loss upon heating. For example, a 2-gram sample of particles is loaded onto a weighing pan of a PM400 Mettler® balance equipped with an LP16 infrared heater. The sample is heated at 160ºC for 20 minutes. The moisture content is displayed as a function of weight loss in percent. The Appropriate moisture content contributes both to the storage stability and, very importantly, to the improved dosing properties of the granules.

The improved dispensing characteristics also obtained by the aforementioned granules can be determined as follows. The detergent granules are stored in closed boxes at 90ºF (32ºC)/80% relative humidity for 4 weeks. After storage, 150 g of the detergent granules are weighed into the main compartment of a HotPoint washing machine storage drawer. The drawer is pre-weighed. Water (20ºC) is flushed through the main compartment drawer for 2 minutes at a rate of 2 liters/min. The excess water in the compartment is drained and the drawer is re-weighed. This experiment is repeated 6 times. The percent residue remaining in the drawer is expressed by the formula below. An acceptable level of residue is less than 15%. The formulations according to the invention undergo this test.

Residue = weight of drawer + product after rinsing - weight of drawer Weight of added product

The above compositions also demonstrate acceptable stability of the percarbonate, i.e. typically less than about 15% degradation as measured in a simple storage test (28ºC, sealed bottle, 6-week storage).

The above compositions according to the invention also show excellent enzyme stability during storage compared to compositions without silicate under the same storage test conditions.

The aforementioned compositions according to the invention also show an improved stability with respect to the complexing agents, the amine-based fabric softeners and the antistatic agents, the perfume and the oleyl sulfate surfactant, compared to compositions without silicate under the same storage test conditions.

Claims (11)

1. Use of a silicate material for reducing or eliminating the oxidative degradation of oxidation-sensitive components in a granular detergent composition containing a percarbonate bleach, the detergent composition comprising: (i) percarbonate bleach particles; and (ii) particles comprising the silicate material. 2. Use of a silicate material according to claim 1, wherein the oxidation-sensitive component is a member selected from the group comprising optical brighteners, perfumes, enzymes, complexing agents, fabric softeners, unsaturated materials and mixtures thereof. 3. Use of a silicate material according to claim 2, wherein the oxidation-sensitive component is an optical brightener of the stilbene type. 4. Granular detergent composition comprising 0.04 to 15 wt% of oxidation-sensitive components in combination with a detergent composition, characterized in that it comprises: (a) 10 to 85% by weight of the composition of particles comprising: (i) 5 to 80 wt.% of particles of a builder which is a member selected from the group consisting of zeolite builders, carbonate builders and mixtures thereof; (ii) 2 to 15% by weight of a silicate, most preferably a sodium silicate; (iii) 5 to 60% by weight of particles of a detersive surfactant or mixtures of detersive surfactants; (iv) 0 to 70 wt.% of particles of a water-soluble sulfate salt, the sulfate salt being contaminated with not more than 60 ppm iron and not more than 5 ppm copper; (v) 0.3 to 15% by weight of a complexing agent when the water-soluble sulfate salt is present in an amount of 1% or more in the particle; (b) from 3 to 50% by weight of the composition of percarbonate bleach particles having an average particle size in the range of 500 µm to 1,000 µm, wherein not more than 10% by weight of the percarbonate comprises particles of less than 200 µm and not more than 10 wt.% of the particles are not larger than 1,250 µm; (c) 7.7 to 35% by weight of the composition of water-soluble sulfate particles, said particles being dry-blended with particles (a) and (b), said sulfate particles being contaminated with not more than 40 ppm iron and not more than ppm copper, said sulfate particles having an average particle size in the range of 250 µm to 1,400 µm, not more than 25% by weight of said sulfate particles being larger than 1,000 µm and not more than 2% of said particles being smaller than 250 µm; and (d) optional additional components. 5. Composition according to claim 4, wherein particle (a) has a moisture content which does not exceed 13% by weight. 156. The composition of claim 5, wherein particle (a) has a moisture content of at least 2% by weight. 7. The composition of claim 4, wherein particle (a) comprises a builder selected from the group comprising zeolites A, P, MAP, X, Y or mixtures thereof, sodium carbonate builders and mixtures thereof. 8. A composition according to claim 4, wherein the percarbonate particles (b) have a moisture content of not more than 1% by weight based on the percarbonate particles. 9. A composition according to claim 4, wherein the particles of the sulfate (c) contain less than 25 ppm iron and have an average particle size in the range of 450 µm to 800 µm. 3010. Composition according to claim 4, wherein the moisture content of the total composition is not greater than 8% by weight. 11. The composition of claim 4, wherein the oxidation-sensitive ingredient is the optical brightener 4,4'-bis-[4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]-stilbene-2,2'-disulfonate.