EP0117569A1

EP0117569A1 - Detergent compositions containing polyacetal carboxylate detergency builders

Info

Publication number: EP0117569A1
Application number: EP84200054A
Authority: EP
Inventors: Thomas Edward Cook; William Ajalon Cilley
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1983-01-28
Filing date: 1984-01-18
Publication date: 1984-09-05
Also published as: GR79172B; JPS59187098A; AU2387084A

Abstract

Detergent compositions are disclosed which contain polyacetal carboxylates as detergency builders, said compositions providing a washing solution pH of from about 6 to about 8.5 in a 0.2% by weight solution in water at 20 °C.

Description

Technical Field

This invention relates to detergent compositions containing polyacetal carboxylate detergency builder materials and which - - provide a pH of from about 6.0 to about 8.5 in aqueous washing solutions. These compositions deliver excellent soil removal performance relative to detergent compositions containing other types of polycarboxylate and polyphosphate detergency builder materials at said pH.

Background Art

The property possessed by some materials for improving detergency of surface active agents such as soaps and synthetic detergents and the use of such materials in detergent compositions is known. Such cleaning boosters have been called detergency builders and such builders permit the attainment of better cleaning performance than is possible when so-called unbuilt compositions are used. The mechanisms by which builders perform their function are only partially understood. It is known that good builders must be able to effectively remove the alkaline earth metal ions, particularly calcium ions, from the wash water by precipitation or sequestration since these ions can be detrimental to the detergency process. The provision of reserve alkalinity has also been considered an important function of detergency builders. However, it is difficult to predict which compounds possess detergency builder properties under a specific set of conditions and which compounds do not. This is due to the complex nature of detergency and the countless factors which contribute to overall results.
Sodium tripolyphosphate (STP) has been found to be a highly efficient detergency builder and this compound has been widely used for decades in detergent formulations. However, because of the recent emphasis on removing phosphates from detergent compositions for environmental reasons, the detergent industry has been looking for materials suitable for use as detergency builders which do not contain phosphorus, and which are environmentally acceptable from other standpoints such as biodegradability. It has been difficult, however, to simultaneously deliver effective cleaning performance and biodegradability from materials that contain no phosphorus. Inorganic builders other than polyphosphates, e.g., carbonates and silicates, are generally less satisfactory for use as builders in detergent formulations.
At least one type of organic polycarboxylate, specifically a water soluble nitrilotriacetate (NTA) such as sodium nitrilotriacetate, has proven very satisfactory from the standpoints of effectiveness as a detergency builder and biodegradability.
Use of water soluble polyphosphates such as sodium tripolyphosphate and polycarboxylates such as the nitrilotriacetates in detergent compositions tend to provide their water solution with an alkaline pH in the range of 8.5 to 11. It has been generally recognized that optimum fabric detergency for a wide range of fabrics and soils is obtained at pH values above about 9. Alkalinity in itself can have some value in the detergency process, but it also can substantially affect detergency builder performance.
For some fabric washing operations, use of detergent compositions that provide a neutral or less alkaline washing solution than pH 9 is necessary or highly recommended. This includes the washing of "fine" fabrics, such as wool and silk and of fabrics having dyes or finishes not stable at alkaline pH values. Detergent compositions in which the active ingredients from a detergency standpoint are limited to surface active agents (surfactants) are typically employed in such applications. It should be recognized that soaps, i.e., the water soluble salts of fatty acids, generally provide alkaline pH values in water solution. A reduction in the pH value of a soap solution by means of addition of acidic material can cause precipitation of fatty acids and consequent loss of surface activity.
It is an object of this invention to provide detergent compositions that contain effective detergency builders yet provide washing solution pH values of from about 6.0 to about 8.5.
U.S. Patent 4,144,226, Crutchfield et al, discloses ether and acetal carboxylates useful as detergent builders having the emper- ical formula
wherein M is a cation, alkyl group, etc., n averages at least 4 and R₁ and R₂ are radicals which stabilize the polymer. A washing solution between pH 9 and pH 10 is said to be usual.
U.S. Patent 4,146;495, Crutchfield et al, disposes detergent compositions containing a polymer with polyacetal carboxylate segments of the structure
where M is a cation and n is at least 4, the segments comprising at least 50% of the polymer by weight.
U.S. Patent 4,233,422, Dryroff et ai, discloses a process for making polyacetal carboxylates from an ester of glyoxylic acid and stabilization against rapid depolymerization by addition of terminal alkyl groups via dialkyl sulfate and metal hydride addition.
U.S. Patent 4,204,052, Crutchfield et al, discloses copolymers of acetal carboxylates and their use in detergent compositions. The patent states that the compounds of the invention will be used generally in an alkaline medium
U.S. Patent Disclosure T995,003, Zimmerman, discloses detergent compositions containing acetal carboxylate polymers, a chlorine bleach and a surfactant.
Canadian Patent 941,765, Mast, discloses detergent compositions providing a solution pH of 6 to 8.5 and containing: (a) a specified non-calcium sensitive surfactant; (b) a proteolytic enzyme with activity in the pH range of 6 to 8.5; and (c) a polycarboxylate builder compound.
U.S. Patent 3,658,727, Mast, discloses phosphorus containing builders in detergent compositions containing a proteolytic enzyme, said compositions providing a solution pH of 6 to 8.5.
U.S. Patent 4,284,524, Gilbert, discloses detergent compositions containing polyacetal carboxylates. A solution pH range of 9 to 10.9 is specified.
European patent application 0 015 024, published 03.09.80,discloses detergent compositions containing a combination of polyacetal carboxylate and aluminosilicate as the builder. It is disclosed that the pH of detergent solutions is usually between 9 and 10.
European patent application 0 021 491, published 07.01.8l,discloses the combination of polycarboxylates, including polyacetals, and aluminosilicate builders in a nonioniclcationic surfactant system. It is disclosed that the compositions are preferably formulated so as to have a pH of at least about 7 in a laundry solution. Preferred compositions are said to have the ability to maintain a pH of about 8 to 11 throughout the washing operation.
European patent application 0 095 205, published 30.11.83,discloses detergent compositions containing 5-40% fatty acid which provide an initial pH of 6.0 to 8.5 in the washing solution. The possible use of polyacetal polycarboxylates is disclosed by incorporation by reference of U.S. Patent 4,284,532, Leikhim et at.

Summary of the Invention

The present invention encompasses a detergent composition, which contains:

(a) from about 3% to about 40% by weight of a surfactant selected from the group consisting of anionic, cationic, nonionic, ampholytic and zwitterionic surfactants and mixtures thereof; and
(b) from about 5% to about 70% by weight of a stabilized water-soluble polymer comprising polyacetal carboxylate segments having the structure:
wherein M is selected from the group consisting of alkali metal, ammonium, tetralkyl ammonium and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl chain; n averages at least 4; and the total number of polyacetal carboxylate segments comprise at least 50% by weight of the total polymer,

In a preferred embodiment, the detergent composition contains from about 0.005% to about 0.4% by weight of pure enzymes selected from the group consisting of proteolytic enzymes, amylolytic enzymes and mixtures thereof, said enzymes preferably having activity in the pH range of 6.0 to 8.5 than at higher pH values.
In another preferred embodiment, the detergent composition contains a peroxygen bleaching agent selected from the group consisting of peroxyacid bleaching agents and peroxyacid precursors comprising peroxy compounds in combination with a peroxygen bleach activator, said peroxyacid bleaching agent and peroxyacid, formed by the reaction of said peroxy compound and said peroxygen bleach activator, preferably having pKa values below about 8.5.

Disclosure of the Invention

This invention relates to the use of an improved detergency builder for use in detergent compositions that provide washing solution pH values from about 6.0 to about 8.5. The builder delivers excellent particulate soil removal performance at low pH values relative to other detergency builders and provides conditions at which certain detergent composition adjuncts can deliver their full potential benefit to the detergency process.
The essential materials in the detergent composition of this invention are a detergent surfactant and a polyacetal carboxylate detergency builder material.

Surfactant

The detergent surfactant represents from about 3% to about 40%, preferably from about 5% to about 30%, and more preferably from about 10% to about 20% by weight of the detergent composition. Suitable surfactants are any of those generally known in the art. More specifically, the surfactant can be selected from the group consisting of anionic, nonionic, ampholytic, zwitterionic and cationic surfactants, and compatible mixtures thereof.
Suitable surfactants for use herein are described in U.S. Patent 3,936,537, Baskerville et at, issued February 3, 1976, the disclosure of which are incorporated herein by reference.
Anionic surfactants useful herein are disclosed in U.S. Patent 3,664,961, Norris, issued May 23, 1972, and in U.S. Patent 3,919,678, Laughlin et al, issued December 30, 1975, both incorporated herein by reference.
Useful anionic surfactants include the water-soluble salts, particularly the alkali metal, ammonium and alkylolammonium salts, of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 10 to about 20 carbon atoms and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of aryl groups.) Examples of this group of synthetic surfactants are the sodium and potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C₈-C₁₈ carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkylbenzene sulfonates in which the alkyl group contains from about 9 to about 15 carbon atoms, in straight chain or branched chain configuration, e.g., those of the type described in U. S. Patents 2,220,099 and 2,477,383. Especially valuable are linear straight chain alkylbenzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 11 to 13, abbreviated as C_11-13LAS.
Other anionic surfactants herein are the sodium alkyl glyceryl ether sulfonates, especially those ethers of higher alcohols derived from tallow and coconut oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfates containing from about 1 to about 4 units of ethylene oxide per molecule and wherein the alkyl groups contain from about 8 to about 12 carbon atoms; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing about 1 to about 4 units of ethylene oxide per molecule and wherein the alkyl group contains from about 10 to about 20 carbon atoms.
Other useful anionic surfactants herein include the water-soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxy-alkane-l-sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; alkyl ether sulfates containing from about 10 to 20 carbon atoms in the alkyl group and from about 1 to 4 motes of ethylene oxide; water-soluble salts of olefin sulfonates containing from about 12 to 24 carbon atoms; and beta-alkyloxy alkane sulfonates containing from about 1 to 3 carbon atoms in the alkyl group and from about 8 to 20 carbon atoms in the alkane moiety.
Water-soluble salts of the higher fatty acids, i.e., "soaps", can be useful anionic surfactants herein, but as discussed hereinafter, are not necessarily stable throughout a pH range of from about 6 to about 8.5. Soaps can be made by direct saponification of fats and oils or by the neutralization of free fatty acids. Examples of soaps are the sodium, potassium, ammonium, and alkylolammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, and preferably from about 12 to about 18 carbon atoms. Sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow are commonly employed, but ammonium or substituted ammonium soaps, e.g., ethanolamine soaps, have superior stability at the pH values of washing solutions within the invention.
Particularly preferred anionic surfactants are the alkali metal (especially sodium) salts of C_11-13 alkylbenzene sulfonates, C_12-18 alkyl sulfates, C_12-18 alkyl polyethoxy sulfates containing from about 1 to about 4 moles of ethylene oxide, and mixtures thereof.
Anionic surfactants in which the cation is magnesium can find use in the compositions of the invention. The polyacetal carboxylate segments of the detergency builder will preferentially sequester calcium ions from washing solutions.
Nonionic surfactants can be prepared by a variety of methods well known in the art. As described hereinafter many nonionic surfactants are prepared by condensing ethylene oxide with an -OH containing hydrocarbyl moiety, e.g., an alcohol or alkyl phenol, under conditions of acidic or basic catalysis.
Nonionic surfactants for use herein comprise the typical nonionic surface active agents well known in the detergency arts. Useful nonionic surfactants include those described in U.S. Patent 4,075,118, issued to Gault et al on February 21, 1978, in U.S. Patent 4,079.078, issued to Collins on March 14, 1978, and in U.S. Patent 3,963,649, issued to Spadini et al on June 15, 1976, all incorporated herein by reference.
Suitable, water-soluble, nonionic surface-active agents useful in the detergent composition of the present invention include:

1. Water-soluble, semi-polar nonionic, tertiary amine oxides represented by the general formula
wherein the arrow is a conventional representation of a semi-polar bond; R₁ represents a high molecular, straight or branched, saturated or unsaturated, aliphatic hydrocarbon, hydroxyhydro- carbon, or alkyloxyhydrocarbon radical, preferably an alkyl radical, having a total 8 to 24, preferably 12 to 18, most preferably 12 carbon atoms, or a mixture of dodecyl with decyl and tetradecyl radicals, whereby at least 50% of the radicals are dodecyl; R₂ and R₃, which may be the same or different, represent each a methyl, ethyl, hydroxymethyl, and hydroxyethyl radical. They are generally prepared by direct oxidation of appropriate tertiary amines, according to known methods. A specific example of a tertiary amine oxides is dimethyldodecylamine oxide.
2. Water-soluble, semi-polar nonionic, tertiary phosphine oxides as represented hereinafter by the general formula
wherein R₁, R₂ and R₃ have the same meaning as hereinbefore for amine oxides, and the arrow is a conventional representation of a semi-polar bond, and which can be prepared by alkylating an alkyl phosphine derivative and oxidizing said reaction product - - as described for example in the French patent specification No. 1,317,586.
3. Water-soluble amides as represented by the general formula R₄--CO-N(H)_m-1(R₅OH)_3-m wherein R₄ is saturated or unsaturated, aliphatic hydrocarbon radical having from 7 to 21, preferably from 11 to 17 carbon atoms; R₅ represents a methylene or ethylene group; and m is 1, 2, or 3, preferably 1. Specific examples of said amides are mono-ethanol coconut fatty acid amide, diethanol dodecyl fatty acid amide, and dimethanol oleyl amide;
4. Condensation products obtained by condensing from 1 to about 20 moles of ethylene oxide with one mote of an organic, hydrophobic compound, aliphatic or alkyl aromatic in nature, having 8 to 24 carbon atoms, and at least one reactive hydrogen atom, preferably a reactive hydroxyl, amino, amido, or carboxy group.

General examples are:

a. the condensates of ethylene oxide with aliphatic alcohols of more than 8 carbon atoms. The alcohols can be derived from the naturally occurring fatty acids, but also from various branched-chain higher alcohols. among the preferred alcohol-ethylene oxide condensation products are those made from alcohols derived from tallow and coconut fatty acids. The alcohols may be primary, secondary, or tertiary. Most preferred are condensation products of about 1 to about 12 moles of ethylene oxide per mole of an aliphatic alcohol having from 9 to about 18 carbon atoms;
b. condensates of ethylene oxide with alkylphenols,. whereby the phenols may be mono- or polyalkylated and the total number of side-chain carbon atoms is as low as 5 to as high as 18 carbon atoms. The aromatic nucleus bearing the phenolic hydroxyl may be benzene, naphthalene, or diphenyl, preferably benzene. Specific examples are condensation products of one mole nonylphenol with 9 to 15 moles of ethylene oxide;
c. condensates of ethylene oxide with the fatty acid esters, preferably mono-fatty acid esters of the sugar alcohols, sorbitol and manitol, and, but less preferred, of di- and polysaccharides. Specific examples are the polyoxyethylene sobitan-monolauric acid esters, having 20 and more thylene oxide units; and the polyoxyethylene derivatives of fatty acid partial esters of hexitol anhydrides generally known under the trade name TWEEN; ICI America, Inc., Wilmington, Del.;
d. polyethenoxy esters or esters made by reacting ethylene oxide with carboxylic acids. The acids can be natural fatty acids or fatty acids made from oxidized paraffin wax, or mono- or polyalkylated benzoic and naphthenic acids. Preferred are aliphatic fatty acids having from 10 to 20 carbon atoms, and benzoic acids with 5 to 18 carbon atoms in the alkyl groups. Specific examples and preferred condensation products are tall oil- ethylene oxide and oleic acid-ethylene oxide condensation products having 9 to 15 ethylene oxide units;
e. condensation products of fatty acyl alkanolamides of the type C_7-17 alkyl-CO-NHC₂HqOH, C_7-17 alkyl-CO-N-(C₂H₄OH)₂ with ethylene oxide. Preferred are condensation products of one more coconut-CO-N-(C₂H₄OH)₂ with ethylene oxide. Preferred are condensation products of one mole coconut-CO-NH-C₂H₄OH with 5 to 20 moles of ethylene oxide. Specific examples of polyethenoxy alkanolamides of fatty acids are the commercial products, marketed under the trade name ETHOMID; Armak Industrial Chemicals, Chicago, III.;
f. condensation products of C_8-18 alkyl, C_8-18 alkenyl and C_5-18 alkylaryl amines and ethylene oxide. A specific and preferred example is the condensation product of one mole of a dodecylamine with 9-12 moles of ethylene oxide;
g. copolymers of ethylene oxide and propylene oxide having a molecular weight of from about 500 to 15,000, preferably from about 1000 to 5000, and containing from about 40% to about 95% by weight of ethylene oxide. Such copolymers can optionally contain hydroxy or amine groups onto which the alkylene oxides can be polymerized. Condensates of ethylene oxide with a hydrophobic base formed by condensing propylene oxide with propylene glycol are preferred copolymers.

5. Alkylpolysaccharides having a hydrophobic group containing from about 8 to about 20 carbon atoms and a polysaccharide hydrophilic group containing from about 1.5 to about 10 saccharide units.
It is to be recognized that mixtures of the foregoing nonionic surfactants are also useful herein.
Preferred nonionic surfactants herein are those obtained by the condensation of from about 1 to 12 moles of ethylene oxide with a C₁₀-C₂₀ aliphatic alcohol. Especially preferred are those obtained by the condensation of from about 5 to 8 moles of ethylene oxide with a C₁₂-C₁₅ aliphatic alcohol.
An especially preferred nonionic surfactant is obtained by the condensation of about 6 to 7 moles of ethylene oxide with a C₁₂-C₁₃ aliphatic alcohol.
Ampholytic surfactants include derivatives of aliphatic or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic moiety can be straight chain or branched and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and at least one aliphatic substituent contains an anionic water-solubilizing group.
Zwitterionic surfactants include derivatives of aliphatic, quaternary, ammonium, phosphonium, and sulfonium compounds in which one of the aliphatic substituents contains from about 8 to 18 carbon atoms.
Cationic surfactants useful in the compositions of the invention include quaternary ammonium compounds having the formula:
wherein R is an alkyl or alkyl benzyl group having from about 8 to about 18 carbon atoms in the alkyl chain; each R³ is selected from the group consisting of -CH₂CH₂-, -CH₂CH(CH₃)-, -CH CH-(CH₂0H)-, -CH₂CH₂CH₂-, and mixtures thereof; each R⁴ is selected from the group consisting of C_1-4 alkyl, C_1-4 hydroxyalkyl, benzyl, ring structures formed by joining the two R⁴ groups, -CH₂CHOHCHOHCOR⁶CHOHCH₂0H wherein R⁶ is any hexose or hexose polymer having a molecular weight less than about 1000, and hydrogen when y is not 0; R⁵ is the same as R⁴ or is an alkyl chain wherein the total number of carbon atoms of R² plus R⁵ is not more than about 18; each y is from 0 to about 10 and the sum of the y values is from 0 to about 15; and X is any compatible anion.
Preferred of the above are the alkyl quaternary ammonium surfactants, especially the mono-long chain alkyl surfactants described in the above formula when R⁵ is selected from the same groups as R⁴. In general, di-long chain alkyl quaternary ammonium surfactants are not compatible with anionic surfactants without physical separation as disclosed in U.S. Patent 3,936,537 issued February 3, 1976, to Baskerville et al, incorporated herein by reference. The most preferred quaternary ammonium surfactants are the chloride, bromide and methylsulfate C_8-16 alkyl trimethylammonium salts, C_8-16 alkyl di(hydroxyethyl)methylammonium salts, the C_8-16 alkyl hydroxyethyldimethylammonium salts, and C_8-16 alkyloxypropyltrimethylammonium salts. Of the above, decyl trimethylammonium methylsulfate, lauryl trimethylammonium chloride, myristyl trimethylammonium bromide and coconut trimethylammonium chloride and methylsulfate are particularly preferred.
Under cold water washing conditions, i.e., less than about 65°F. (18.3°C), the C_8-10 alkyltrimethyl ammonium surfactants are particularly preferred since they have a lower Kraft boundry and, therefore, a lower crystallization temperature than the longer alkyl chain quaternary ammonium surfactants herein.
Cationic diquaternary ammonium surfactants useful herein are of the formula:
wherein the R², R³, R⁴, R⁵, y and X substituents are as defined above for the quaternary ammonium surfactants. These substituents are also preferably selected to provide diquaternary ammonium surfactants corresponding to the preferred quaternary ammonium surfactants. Particularly preferred are the C_8-16 alkyl pentamethylethylenediammonium chloride, bromide and methylsulfate salts.
Cationic amine surfactants useful herein are of the formula:
wherein the R², R³, R⁴, R and y substituents are as defined above for the quaternary ammonium surfactants. Particularly preferred are the C_12-16 alkyl dimethyl amines.
Cationic diamine surfactants useful herein are of the formula
wherein the R², R³, R⁴, R⁵ and y substituents are as defined above. Preferred are the C_12-16 alkyl trimethylethylene diamines. The disclosure and compositions of European Patent Application 0 095 205, published 30.11.1983, bv Wertz et al. are incorporated herein by reference.
In one embodiment of the present invention, the detergent surfactant is selected from the group consisting of cationic and nonionic surfactants, and mixtures thereof, particularly those described in U.S. published Patent Applications 4,222,905, Cockrell, filed June 26, 1978; 4,259,217, Murphy, filed June 26, 1978; and European Patent Application 0 004 121, Murphy, published September 19, 1979; the disclosures of which are incorporated herein by reference.
In preferred embodiments of the invention, the surfactant comprises at least about 30% anionic surfactant by weight of total surfactant and any cationic surfactant does not comprise compounds with more than a single C_12-18 alkyl group.

Polyacetal Carboxylate

The detergent compositions herein contain from about 5% to about 70%, preferably from about 10% to about 50%, by weight of a stabilized water-soluble polymer comprising polyacetal carboxylate segments having the structure
wherein M is selected from the group consisting of alkali metal, ammonium, tetraalkyl, ammonium and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl and alkanol chains; n averages at least 4; and the total number of polyacetal carboxylate segments comprise at least 50% by weight of the total polymer.
The polyacetal carboxylates for use herein are more fully described in U.S. Patent 4,146,495 of Crutchfield et aI, the disclosure of which is incorporated herein by reference.
These polyacetal carboxylates can be prepared by bringing together under polymerization conditions an ester of glyoxylic acid and a polymerization initiator. The resulting polyacetal carboxylate ester is then attached to chemically stable end groups to stabilize the polyacetal carboxylate against rapid depolymerization in alkaline solution, converted to the corresponding salt, and added to a surfactant.
For the purposes of this invention, the term "rapid depolymerization in alkaline solution" shall mean that in an aqueous solution of 0.5 molar sodium hydroxide containing 10 grams per liter of polyacetal carboxylate, the average chain length of the polyacetal carboxylate will be reduced by more than 50%, as determined by Proton Magnetic Resonance, after 1 hour at 20°C.
Any number of esters of glyoxylic acid can be used to prepare the polyacetal carboxylates of the present invention. Such esters can be made by the reaction of an alcohol containing from 1 to 4 carbon atoms with glyoxylic acid hydrate under conditions known to those skilled in the art. Thereafter, the ester hemiacetal can be converted to the corresponding aldehyde ester by any number of techniques known to those skilled in the art, such as the reaction of the ester hemiacetal with phosphorus pentoxide. The product of the above reaction is then polymerized by techniques known to those skilled in the art using an initiator in accordance with the following genera! equation:
The resulting polyacetal carboxylate ester is then reacted at its termini with a reagent which produces a chemically stable end group to stabilize the polyacetal carboxylate against rapid depolymerization. The stabilized polyacetal carboxylate is then reacted with a base, such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, alkanolammonium hydroxide, and the like to make the polyacetal carboxylate salt suitable for use as a builder and as a sequestrant.
The glyoxylic acid can be converted to the ester by reaction with any number of alcohols, such as methanol, ethanol, propanol, isopropanol, and the like. It is only necessary that the ester group does not interfere with the subsequent polymerization. Methanol is preferred.
Any number of initiators can be used for the polymerization. Nonionic or ionic initiators provide satisfactory results. Suitable initiators include 2-hydroxypyridine -H₂0 complex; triethyl amine; ethylvinyl ether trifluoroacetic acid, and the like. Even traces of hydroxy ion or cyanide ion will trigger the polymerization under nonaqueous conditions. Compounds such as diethylsodiomalonate or sodiomethylmalonate esters have been used with good results.
Any number of chemically reactive groups can be added to the polyacetal carboxylate termini to stabilize the polyacetal carboxylate against rapid depolymerization. The specific nature of the chemically reactive group is not important in the proper function of the polyacetal carboxylate in its intended use. As an example, suitable chemically stable end groups include stable substituent moieties derived from otherwise stable compounds, such as alkanes, such as decane, dodecane, octadecane and the like; alkenes such as ethylene, propylene, butylene, decene, dodecene and the like; branched chain hydrocarbons, both saturated and unsaturated, such as 2-methyl butane, 2-methyl butene, 4-butyl-2,3-dimethyl octane and the like; aromatic hydrocarbons such as benzene, toluene, xylene and the like; cycloalkanes and cycloalkenes such as cyclohexane and cyclohexene and the like; haloalkanes such as chlorobutane, dichloropentane and the like; alcohols such as methanol, ethanol, 2-propanol, cyclohexanol and the like; polyhydric alcohols such as 1 ,2-ethane diol, 1,4-benzene diol and the like; mercaptans such as methane thiol, 1 ,2-ethanedithiol and the like; ethers such as methoxyethane methyl ether, ethyl ether, ethoxypropane and cyclic ethers such as ethylene oxide, epichlorohydrin, tetramethylene oxide and the like; aldehydes and ketones such as ethanol, acetone, propanal, methylethyl ketone and the like; and carboxylate-containing compounds such as the alkali metal salts of carboxylic acids, the esters of carboxylic acids and the anhydrides. The above listing is intended to be instructive and is not intended to be limited since chemically stable end groups that stabilize the polyacetal carboxylate against rapid depolymerization include nitrilo groups and halides such as chlorides, bromides and the like. Particularly suitable end groups include alkyl groups and cyclic alkyl groups containing oxygen: such as oxyalkyl groups like methoxy, ethoxy and the like; carboxylic acids such as -CH₂COOM,
and the like; aldehydes, ethers and other oxygen-containing alkyl groups such as -OCHCH₃OC₂H₅, (̵OCH₂CH₂O)̵_1-4OH, (̵OCH₂CH₂O)-_1-4H,
and the like. In the above examples of suitable end groups, M is alkali metal, ammonium, alkanol amine, alkyl groups having 1 to 4 carbon atoms, tetraalkyl ammonium groups and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl chain, and R is hydrogen or alkyl group of 1 to 8 carbon atoms. As will occur to those skilled in the art in light of the present disclosure, the chemically stable end groups at the polyacetal carboxylate termini can be alike or unlike.
As a further example of the polyacetal carboxylates of the present invention wherein the end groups can be different, one end group can be a polymer, and particularly a polymer with an anionic charge, which permits one or more of the polyacetal carboxylates of the present invention to be appended to the polymer, or on the other hand, the polyacetal carboxylates of the present invention can be the part of a block copolymer having a polymer chain at each of the polyacetal carboxylate termini. Preferred polymers that are anionic or can be made anionic include: polymers of cellulose acetate, cellulose propionate, cellulose acetate butyrate, polyvinyl acetate, polyvinyl alcohol and the like. In the case of an anionic polymer, the polymer can be used to initiate the polymerization to form the polyacetal carboxylates wherein the polymer adds to the termini as one of the chemically stable end groups to stabilize that end of the polyacetal carboxylate against rapid depolymerization and thereafter the other end of the polyacetal carboxylate can be stabilized with a compound such as ethylene oxide or the like, as described above.
In one embodiment of this invention, diethylsodiomalonate or sodiomethylmalonate is used as an initiator to form the polymer. These compounds not only serve to initiate the polymerization, but also the ester adds to the termini as one of the chemically stable end groups to stabilize that end of the polyacetal carboxylate against rapid hydrolysis in an alkaline solution. These compounds can be prepared from the corresponding esters using sodium hydride in a solvent, such as tetrahydrofuran, by techniques known to those skilled in the art.
Accordingly, it can be seen that in one embodiment of this invention the builder mixture contains a water-soluble polyacetal carboxylate havinq the structure;
wherein M is selected from the group consisting of alkali metal, ammonium, tetraalkyl ammonium groups and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl chain; n averages at least 4; and R₁ and R₂ are individually any chemically stable group which stabilizes the polyacetal carboxylate against rapid depolymerization.
The number of repeating units, i.e., the value of n, in the polyacetal carboxylate is important since the effectiveness of the polyacetal carboxylate salt as a detergency builder is affected by the chain length. Even when there are as few as four repeating units (i.e., n averages 4), the polyacetal carboxylate salt shows some effectiveness as a sequestrant, chelating agent and builder. Although there is no upper limit to the desired number of repeating units, which may be as high as 400, or even higher, there does not seem to be an advantage to having more than about 200 repeating units. When the number of repeating units exceeds about 100, significant improvement in sequestration, chelating and builder properties is not observed. Thus, it is preferred that the polyacetal carboxylate contain between about 10 and about 200 units, and even more preferred that the polyacetal carboxylate contains between about 50 and about 100 repeating units.
The most important factors believed to control the chain length include (1) the initiator concentration, (2) the temperature of the polymerization, (3) the purity of the starting materials, and (4) the presence of solvents and their levels. As will occur to those skilled in the art, the concentration of the initiator, solvents and their levels, and the temperature of the polymerization reaction are all interrelated and the desired chain length can easily be controlled by simple experimentation by controlling these variables. Generally speaking, the lower the temperature at the beginning of the polymerization, the higher the chain length. For example, when polymerization was initiated with one mole percent 2-hydroxy pyridine -H₂0 complex at a temperature of -70°C., the resulting polyacetal carboxylate contained 60 repeating units as determined by Proton Magnetic Resonance (PMR). On the other hand, when one mole percent 2-hydroxy pyridine -H₂0 complex was used at about 20°C, the resulting polyacetal carboxylate had only about 20 repeating units.
The polyacetal carboxylate can also contain other polymer fragments, and accordingly, the polymer can be a linear homopolymer or copolymer, or it can be branched. To form a copolymer, the polyacetal carboxylate segments are polymerized with any number of chain extending agents known to those skilled in the art. It is only necessary that the chain extending agent does not cause the polyacetal carboxylate to depolymerize or become insoluble in water. Either aliphatic or aromatic chain extending agents can be used, but aliphatic chain extending agents are preferred to make the polymer more environmentally acceptable, and aliphatic chain extending agents having from 1 to 4 carbon atoms, such as ethylene oxide or propylene oxide, are especially preferred.
It is important that a copolymer contains at least 4 repeating units (i.e., n averages at least 4) of the acetal carboxylate to insure that the copolymer will effectively sequester calcium and magnesium ions and provide builder properties. It is preferred that the copolymer contain at least 10 repeating units of acetal carboxylate, or more, say 50 or 100 repeating units, for the reasons described above. As will occur to those skilled in the art in light of the present disclosure, having at least 4 acetal carboxylate units in a copolymer prepared by block or graft polymerization techniques should not present a problem, but when acetal carboxylate esters are copolymerized with a chain extending agent, the amount of acetal carboxylate should be at least about 50% by weight, based on the total weight of the polymer, to insure that the polymer will effectively sequester calcium and magnesium ions and retain its builder properties. It is preferred that the amount of acetal carboxylate is 80% by weight, based on the total weight of the polymer, or even higher.
As will occur to those skilled in the art, any number of chain extending agents can be copolymerized with the polyacetal carboxylates of the present invention. It is only necessary that the chain extending agent will provide at least two reactive sites. Suitable chain extending agents include: polyhydric alcohols, such as ethylene glycol, propylene glycol and the like; epoxy compounds, such as ethylene oxide, propylene oxide, epihalohydrin epoxysuccinates and the like; aldehydes, such as formaldehyde, acetaldehyde, and the like. It is particularly beneficial when the chain extending agent contains substituent carboxy groups.
Thus, it can be seen that in one embodiment of this invention the builder mixture contains a stabilized water-soluble polymer comprising polyacetal carboxylate segments having the general formula:
where Y is at least one chain extending agent, preferably alkyl or oxyalkyl having 1 to 4 carbon atoms, p averages at least 4, q is at least 1, and M is selected from the group consisting of alkali metal, ammonium, tetraalkyl ammonium groups and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl chain. Furthermore, the polyacetal carboxylates having a chain extending agent can be stabilized by the same techniques used above using suitable reagents or polymers as described above.
The polyacetal carboxylate ester can be converted to the corresponding alkali metal, ammonium, tetraalkyl ammonium or alkanol amine salts by conventional saponification techniques. Generally, the use of the alkali metal salts, particularly the sodium salt, is preferred. However, in some formulations where greater builder solubility is required, the use of ammonium or alkanol ammonium salts may be desirable.
The detergent compositions of the invention provide a pH of from about 6 to about 8.5, preferably from about 6.5 to about 8, and most preferably about 7, in a 0.2% by weight water solution at 20°C. This characteristic can be provided by any suitable means including the addition of acidic material or use of anionic surfactants in a unneutralized acid form. The detergent compositions of the invention are generally used in aqueous washing solutions containing from about 0.05% to about 1% of the detergent composition by weight. Use as a laundry detergent composition is a preferred embodiment, but the compositions can also be used for hard surface cleaning such as dishwashing or interior household surfaces.
As disclosed hereinbefore enzymes are useful in the compositions of the invention.
The pure enzyme component can be incorporated in an amount of from about 0.005% to about 0.2%, preferably from about 0.02% to about 0.09%. If incorporated, the proteolytic enzyme component should give to the composition a proteolytic activity of at least about 0.003 Anson Units per liter, preferably from about 0.003 to about 0.125 Anson Units per liter of wash solution and most preferably, from about 0.016 to about 0.063 Anson Units per liter of wash solution. Above about 0.1 Anson units per titer of wash solution additional proteolytic enzyme provides only a minimal increase in performance. Other enzymes including amylolytic enzymes or amalyses can be incorporated, e.g. Rapidase (Gist-Brocades N.V.) and Termamyl (Novo Industri AS). The cleaning advantages contributed by amylolytic enzymes is particularly enhanced by the low solution pH values provided by _- compositions of the invention.
Preferably the enzyme components are characterized by an isoelectric point of from about 6 to about 9, most preferably from about 6.5 to about 8.5. Preferred enzymes have an activity at pH values of 6.0 to 8.5 than at higher pH values.
Examples of suitable proteolytic enzymes include many species which are known to be adapted for use in detergent compositions and, in fact, have been used in detergent compositions. Sources of the enzymes include commercial enzyme preparation such as "Alcalase", sold by Novo Industries, and "Maxatase", sold by Gist-Brocades Delft, The Netherlands, which contain from about 10% to about 20% pure enzyme. Other enzyme compositions include those commercially available under the trade names SP-72 ("Esperase"), manufactured and sold by Novo Industries, AS, Copenhagen, Denmark, and "AZ-Protease", manufactured and sold by Gist-Brocades Delft, The Netherlands.
A more complete disclosure of suitable enzymes can be found in U.S. Patent 4,101,457, Place et aI, issued July 18, 1978, incorporated herein by reference.
Peroxygen bleaches useful in the practice of this invention are selected from the group consisting of peroxyacid bleaching agents and peroxyacid precursors comprising peroxy compounds in combination with a peroxygen bleach activator, said peroxyacid bleaching agent and peroxyacid formed by the reaction of said peroxy compound and said peroxygen bleach activator having pKa values below about 8.5. A preferred peroxyacid bleaching agent is metachloroperoxybenzoic acid which has a pKa value of 7.53. Other suitable peroxyacid bleaching agents are perlauric acid and diperoxydodecanedioic acid.
The compositions of this invention can contain detergency builder materials additional to the essential polyacetal carboxylate.
Optional water-soluble detergency builders can be selected from the various water-soluble, alkali metal, ammonium or substituted ammonium phosphates, polyphosphates, phosphonates, polyphosphonates, carbonates, silicates, borates, polyhydroxy sulfonates, polyacetates, carboxylates, and polycarboxylates. Alkali metal, especially sodium, salts are preferred for economy if product stability and solution pH considerations allow their use.
Specific examples of inorganic phosphate builders are sodium and potassium tripolyphosphate, pyrophosphate, polymeric metaphosphate having a degree of polymerization of from about 6 to 21, and orthophosphate. Examples of polyphosphonate builders are the sodium and potassium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane l-hydroxy-1,1-diphosphonic acid and the sodium and potassium salts of ethane, 1,1,2-triphosphonic acid. Other phosphorus builder compounds are disclosed in U.S. Patents 3,159,581, 3,213,030; 3,422,021; 3,422,137; 3,400,176; and 3,400,148, incorporated herein by reference.
Examples of nonphosphorus, inorganic builders are sodium and potassium carbonate, bicarbonate, sesquicarbonate, tetraborate decahydrate, and silicates having a weight ratio of Si0₂ to alkali metal oxide of from about 0.5 to about 4.0, preferably from about 1.0 to about 2.4.
Water-soluble, nonphosphorus organic builders useful herein include the various alkali metal, ammonium and substituted ammonium polyacetates, carboxylates, polycarboxylates and polyhydroxy sulfonates. Examples of polyacetate and polycarboxylate builders are the sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, mellitic acid, benzene polycarboxylic acids, and citric acid.
Polymeric polycarboxylate builders are set forth in U.S. Patent 3,308,067, Diehl, issued March 7, 1967, incorporated herein by reference. Such materials include the water-soluble salts of homo- and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid.
Other useful builders herein are sodium and potassium carboxymethyloxymalonate, carboxymethyloxysuccinate, cis-cyclo- hexanehexacarboxylate, cis-cyclopentanetetracarboxylate, phloro- glucinol trisulfonate, and the copolymers of maleic anhydride with vinyl methyl ether or ethylene.
Additional detergency builders useful herein are water- insoluble crystalline or amorphous aluminosilicate ion exchange materials. Crystalline material useful herein is of the formula
wherein z and y are at least about 6, the molar ratio of z to y is from about 1.0 to about 0.5 and x is from about 10 to about 264. Amorphous hydrated aluminosilicate materials useful herein have the empirical formula
wherein M is sodium, potassium, ammonium or substituted ammonium, z is from about 0.5 to about 2 and y is 1, said material having a magnesium ion exchange capacity of at least about 50 milligram equivalents of CaC0₃ hardness per gram of anhydrous aluminosilicate.
The aluminosilicate ion exchange builder materials herein are in hydrated form and contain from about 10% to about 28% of water by weight if crystalline, and potentially even higher amounts of water if amorphous. Highly preferred crystalline aluminosilicate ion exchange materials contain from about 18% to about 22% water in their crystal matrix. The crystalline aiumi- nosilicate ion exchange materials are further characterized by a particle size diameter of from about 0.1 micron to about 10 microns. Amorphous materials are often smaller, e.g., down to less than about 0.01 micron. Preferred ion exchange materials have a particle size diameter of from about 0.2 micron to about 4 microns. The term "particle size diameter" herein represents the average particle size diameter of a given ion exchange material as determined by conventional analytical techniques such as, for example, microscopic determination utilizing a scanning electron microscope. The crystalline aluminosilicate ion exchange materials herein are usually further characterized by their calcium ion exchange capacity, which is at least about 200 mg equivalent of CaC0₃ water hardness/g of aluminosilicate, calculated on an anhydrous basis, and which generally is in the range of from about 300 mg eq./g to about 352 mg eq./g. The aluminosilicate ion exchange materials herein are still further characterized by their calcium ion exchange rate which is at least about 2 grains/gallon/minute/gram/gallon of aluminosilicate (anhydrous basis), and generally lies within the range of from about 2 to 6 grains/gallon/minute/gram/gallon, based on calcium ion hardness. Optimum aluminosilicate for builder purposes exhibit a calcium ion exchange rate of at least about 4 grains/gallon/minute/gram/gallon.
The amorphous aluminosilicate ion exchange materials usually have a Mg⁺⁺ exchange capacity of at least about 50 mg. eq. CaC0₃/g (12 mg Mg⁺⁺/g) and a Mg⁺⁺ exchange rate of at least about 1 grain/gallon/minutelgram/gallon. Amorphous materials do not exhibit an observable diffraction pattern when examined by Cu radiation (1.54 Angstrom Units).
Aluminosilicate ion exchange materials useful in the practice of this invention are commercially available. The aluminosilicates useful in this invention 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 discussed in U.S. Patent 3,985,669, Krummel, et al, issued October 12, 1976, incorporated herein by reference. Preferred synthetic crystalline aluminosilicate ion exchange materials useful herein are available under the designations Zeolite A, Zeolite B, and Zeolite X. In an especially preferred embodiment, the crystalline aluminosilicate ion exchange material has the formula
wherein x is from about 20 to about 30, especially about 27.
In a preferred embodiment especially suitable for use in liquid detergent compositions, fatty acids containing from about 12 to about 18 carbon atoms are utilized as detergency builders. Such fatty acids are useful to control washing solution pH to within the desired range and act as fatty soil solvents when applied to fabrics in an undiluted form.

Other Optional Ingredients

Other ingredients which are conventionally used in detergent compositions can be included in the detergent compositions of the present invention. These components include other detergency builders, antistatic and fabric-softening agents, color speckles, suds boosters or suds suppressors, anti-tarnish and anticorrosion agents, soil suspending agents, soil release agents, dyes, fillers, optical brighteners, germicides, hydrotropes, perfumes, and other optional detergent compounds.
As used herein, all percentages, parts and ratios given are by weight, unless otherwise specified.
The following nonlimiting examples illustrate the compositions of the present invention.

EXAMPLE I

A liquid detergent having the following composition was prepared:
To the ingredients listed above the following detergency builders were added on an anhydrous basis replacing water:

(A) no builder
(B) 23.9% sodium nitrilotriacetate(l)
(C) 19.5% polymeric acetal carboxylate⁽¹⁾ having the following formula
x being a distribution of values to provide an average molecular weight of approximately 5000 to 6000 on a weight basis.

⁽¹⁾ levels to provide theoretical equivalency of calcium sequestration.
The detergent compositions A, B & C were tested as follows.
Identical clay-soiled polyester/cotton swatches were washed in aqueous solutions having dissolved therein 920 parts per million of the detergent compositions described. Washing solution pH was adjusted by addition of NaOH or HCI as necessary. The swatches were washed for 10 minutes in a miniature washing machine containing 1-1/2 gallons of washing liquor at 100°F and artificial water hardness (molar equivalents of 2 moles Ca to 1 mole Mg⁺⁺) at a level of 4 grains of CaCO₃ equivalent per gallon. The swatches comprised approximately 4% by weight of the washing liquor. After washing, the swatches were spun dry and rinsed with 1-1/2 gallons of water, at 100°F, having the same water hardness as that of the water they were washed in. The swatches were then dried in a miniature electric dryer. A Hunter Reflectometer was used to obtain a reflectance reading (in Hunter Whiteness Units) for each of the laundered swatches. A higher reflectance reading indicates greater cleaning effectiveness. The results were as follows:
Composition C containing the polymeric acetal carboxylate has a cleaning advantage at pH values below 9 relative to Composition B containing a nitrilotriacetate.

EXAMPLE II

(A) no builder
(B) 14.0% sodium nitrilotriacetate⁽¹⁾
(C) 11.1% polymeric acetal carboxylate⁽¹⁾ used in Example 1.

(1) levels to provide theoretical equivalency of calcium sequestration.

The testing procedure of Example 1 was repeated except for product usage of 1770 ppm with the following results:
Composition C containing the polymeric acetal carboxylate has a cleaning advantage at pH values below 9 relative to Composition B containing a nitrilotriacetate.

EXAMPLE III

Washing solutions were prepared containing the following ingredients:
Stained fabrics were prepared using white denim cotton and two natural stains - tea and grape juice.
Stain removal evaluations were conducted using the washing procedure and pH adjustments described in Example I. Added levels of polymeric acetal carboxylate (as in Example 1), sodium tripolyphosphate and metachloroperoxybenzoic acid bleach are tabulated below. Percent stain removal is calculated as follows.
A laundry load consisting of one set of the stained fabrics , four clean terry cloth towels and one terry cloth towel soiled with 1.5 grams of a mixture of artificial body soil and vacuum cleaner soil was placed in the miniature wash system described in Example
After drying, each of the stained fabrics was visually graded by comparing it to its unwashed counterpart. A grading scale of 0 to 5 was used, with 0 indicating no stain removal and 5 indicating 100% stain removal. Each fabric was graded by three graders and the average grade for each fabric was calculated. This average was then scaled from 0 to 100, with 100 being 100% stain removal. Also, the mean for the set of fabrics was calculated.

EXAMPLE IV

(a) A granular detergent composition is prepared having the following composition:
- 35% C₁₂ alkylbenzene sulfonate
- 30% sodium nitrilotriacetate
- 25% sodium sulfate
- remainder water and miscellaneous
The composition is prepared by the agglomeration of dry ingredients with sufficient water to hydrate anhydrous salts.
(b) A granular detergent is prepared having the following coposition:
- 35% C₁₂ alkylbenzene sulfonate
- 25% polymeric acetal carboxylate⁽¹⁾ as used in Example 1
- 30% sodium sulfate
- remainder water and miscellaneous

(1) level to provide theoretical equivalency of calcium sequestration to 30% sodium nitrilotriacetate.

The composition is prepared by the agglomeration of dry materials with sufficient water to hydrate anhydrous salts.
Water solutions containing compositions (a) and (b) at a 0.2% level by weight are prepared and adjusted to a pH of 7 by the addition of H₂S0₄. The detergency of the two solutions is compared following the procedure of Example I. Composition (b) containing a polymeric acetal carboxylate has a detergency advantage over Composition (a) containing sodium nitrilotriacetate at a wash solution pH of 7.

EXAMPLE V

The ability of a detergency builder to sequester calcium ions is a measure of potential effectiveness in detergent compositions.

Sequestration Evaluation Procedure

A calcium ion electrode was used to measure calcium ion sequestration of detergency builder materials. Calcium concentration standards were prepared and used to establish a plot of millivolt values that correspond to a range of calcium ion concentrations with the particular calcium ion electrode.
The procedure was used to measure the extent of Ca⁺⁺ depletion of three detergency builder materials at theoretically equivalent sequestration levels based on carboxylate content (molar basis)
Conclusion: Sodium nitrilotriacetate has an sequestration advantage over the polymeric acetal carboxylate at pH 9.5 when compared at theoretical sequestration equivalence (carboxylate molar basis). The polymeric acetal carboxylate has an advantage at pH 7.5. Polyplymaleic acid is poorer at both pH values.

EXAMPLE VI

An evaluation of the relative effectiveness of three detergency builder materials in detergent compositions containing linear C_11.1 alkyl benzene sulfonate (C_11.1 LAS) was conducted.

Builders: (a) polymeric acetal carboxylate (as in Example I)
(b) sodium nitrilotriacetate
(c) polymaleic acid (Polyscience Lot #3-0823) Minature washers were prepared containing 225 ppm of C_11.1 LAS and 2.8 grams of detergency builder (active basis) in 2 gallons of 100°F water. Water hardness and solution pH as adjusted as indicated below. Cleaning effectivenss was compared using artifically soiled fabrics as indicated. Round robin paired comparison grading of washed, rinsed, and dried fabrics was conducted. Panelists indicated no difference (0), a slight difference (1), a moderate difference (2), a large difference (3), or a very large difference (4), i.e., a nine point scale. Average grades were was follows:

Conclusion: On an equal active compound weight basis the polymeric acetal carboxylate has a cleaning advantage over nitrilotriacetate and polymaleate builder materials. The relative advantage is greater at pH 7.5 than at pH 9.5.

Claims

1. A detergent composition comprising:

(a) from about 3% to about 40% by weight of a surfactant selected from the group consisting of anionic, cationic, nonionic, ampholytic and zwitterionic surfactants and mixtures thereof; and

(b) from about 5% to about 70% by weight of a stabilized water-soluble polymer comprising polyacetal carboxylate segments having the structure:

wherein M is selected from the group consisting of alkali metal, ammonium, tetralkyl ammonium and alkanol amine groups having from 1 to about 4 carbon atoms in the alkyl chain; n averages at least 4; and the total number of polyacetal carboxylate segments comprise at least 50% by weight of the total polymer,

said detergent composition providing a pH of from about 6.0 to about 8.5 in a 0.2% by weight water solution at 20°C.

2. The composition of Claim 1 wherein said detergent composition provides a pH of from about 6.5 to about 8.0 in a 0.2% by weight water solution at 20°C.

3. The composition of Claim 1 which additionally comprises from about 0.005% to about 0.4% by weight of pure enzymes selected from the group consisting of proteolytic enzymes, amylolytic enzymes and mixtures thereof, said enzymes having activity at pH values of 6.0 to 8.5 greater than activity at higher pH values.

4. The composition of Claim 1 which additionally comprises a peroxygen bleaching agent selected from the group consisting of peroxyacid bleaching agents and peroxyacid precursors comprising peroxy compounds in combination with a peroxygen bleach activator.

5. The composition of Claim 1 wherein said compostion is granular.

6. The composition of Claim 1 wherein said composition is liquid.

7. The composition of Claim 2 wherein said composition comprises from about 10% to about 40% of said stabilized water-soluble polymer.

8. The composition of Claim 7 wherein said composition comprises an anionic surfactant.

9. The composition of Claim 8 wherein said anionic surfactant is selected from the group consisting of alkyl sulfates, alkyl ethoxy ether sulfates, alkyl benzene sulfonates, olefin sulfonates, paraffin sulfonates and mixtures thereof.