WO2007138053A1

WO2007138053A1 - Amphiphilic graft polymers based on polyalkylene oxides and vinyl esters

Info

Publication number: WO2007138053A1
Application number: PCT/EP2007/055197
Authority: WO
Inventors: Dieter Boeckh; Lidcay Herrera Taboada; Asimina Kavarnou-Seiler; Gerd Konrad; Birgit Reinhard; Arturo Luis Casado Dominguez; James Lee Danziger; Frank Huelskoetter
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2006-05-31
Filing date: 2007-05-29
Publication date: 2007-12-06
Anticipated expiration: 2008-11-30
Also published as: JP2009538947A; BRPI0712159B1; JP5542434B2; ES2349321T5; EP2029645B1; EP2024479A1; KR20090023374A; WO2007138054A1; US20090176935A1; CA2650067A1; US20090298735A1; EP2024479B1; MX2008014819A; DE602007007940D1; CA2650067C; CA2653880C; US8143209B2; CN101454364B; MX2008015367A; BRPI0711719B1

Abstract

Amphiphilic graft polymers based on water-soluble polyalkylene oxides (A) as a graft base and side chains formed by polymerization of a vinyl ester component (B), said polymers having an average of ≤1 graft site per 50 alkylene oxide units and mean molar masses Mw of from 3000 to 100 000.

Description

Amphiphilic graft polymers based on polyalkylene oxides and vinyl esters

Description

The present invention relates to novel amphiphilic graft polymers based on water- soluble polyalkylene oxides (A) as a graft base and side chains formed by polymerization of a vinyl ester component (B), said polymers having an average of <1 graft site per 50 alkylene oxide units and mean molar masses M_w of from 3000 to 100 000.

The invention also relates to the preparation of these graft polymers.

Graft polymers based on polyalkylene oxides and vinyl esters, in particular vinyl acetate, are known from DE-B-10 77 430 and GB-B-922 457. They are prepared by polymerizing the vinyl ester in the presence of the polyalkylene oxide, the initiator used being dibenzoyl peroxide, dilauroyl peroxide or diacetyl peroxide. In the examples of these documents, the procedure is to prepare a solution from all reactants. This solution is either heated directly to the polymerization temperature or only a portion is initially charged and heated, and the majority is metered in. In the first variant, it is also possible for larger amounts of solvent such a methyl acetate or methanol to be present (100% or 72% based on the amount of polyalkylene glycol, vinyl ester). Further procedures are merely mentioned in GB-B-922 457 but not used in the examples for preparing the graft polymers.

According to EP-A-219 048 and 285 037, graft polymers based on polyalkylene oxides and vinyl esters are suitable as graying inhibitors in the washing and aftertreatment of textiles comprising synthetic fibers. For this purpose, EP-A-285 935 and 285 038 also recommend graft polymers which comprise methyl acrylate or N-vinylpyrrolidone in copolymerized form as an additional graft monomer. For the preparation of the graft polymers used in the examples, no specific data are given; reference is made merely in general terms to DE-B-10 77 430 and GB-B-922 457.

In contrast to the inventive graft polymers, the graft polymers prepared according to the specifications in DE-B-10 77 430 and GB-B-922 57 are relatively highly branched (> 1 graft site per 50 alkylene oxide units) and have a broad molar mass distribution (poly- dispersity > 3).

It was an object of the invention to provide polymers which are suitable as an additive to washing and cleaning compositions, especially to remove hydrophobic soil from textile and hard surfaces.

We have accordingly found amphiphilic graft polymers based on water-soluble polyalkylene oxides (A) as a graft base and side chains formed by polymerization of a vinyl ester component (B), said polymers having an average of < one graft site per 50 alkylene oxide units and mean molar masses M_w of from 3000 to 100 000.

We have also found a process for preparing graft polymers, which comprises polymer- izing a vinyl ester component (B) composed of vinyl acetate and/or vinyl propionate (B1) and, if desired, a further ethylenically unsaturated monomer (B2), in the presence of a water-soluble polyalkylene oxide (A), a free radical-forming initiator (C) and, if desired, up to 40% by weight, based on the sum of components (A), (B) and (C), of an organic solvent (D), at a mean polymerization temperature at which the initiator (C) has a decomposition half-life of from 40 to 500 min, in such a way that the fraction of unconverted graft monomer (B) and initiator (C) in the reaction mixture is constantly kept in a quantitative deficiency relative to the polyalkylene oxide (A).

The inventive graft polymers are characterized by their low degree of branching (de- gree of grafting). They have, on average, based on the reaction mixture obtained, not more than 1 graft site, preferably not more than 0.6 graft site, more preferably not more than 0.5 graft site and most preferably not more than 0.4 graft site per 50 alkylene oxide units. They comprise, on average, based on the reaction mixture obtained, preferably at least 0.05, in particular at least 0.1 graft site per 50 alkylene oxide units. The de- gree of branching can be determined, for example, by means of ¹³C NMR spectroscopy from the integrals of the signals of the graft sites and the -Chb-groups of the polyalkylene oxide.

In accordance with their low degree of branching, the molar ratio of grafted to ungrafted alkylene oxide units in the inventive graft polymers is from 0.002 to 0.05, preferably from 0.002 to 0.035, more preferably from 0.003 to 0.025 and most preferably from 0.004 to 0.02.

The inventive graft polymers feature a narrow molar mass distribution and hence a polydispersity M_w/Mn of generally < 3, preferably < 2.5 and more preferably < 2.3. Most preferably, their polydispersity M_w/M_n is in the range from 1.5 to 2.2. The polydispersity of the graft polymers can be determined, for example, by gel permeation chromatography using narrow-distribution polymethyl methacrylates as the standard.

The mean molecular weight M_w of the inventive graft polymers is from 3000 to 100 000, preferably from 6000 to 45 000 and more preferably from 8000 to 30 000.

Owing to their low degree of branching and their low polydispersity, the amphiphilic character and the block polymer structure of the inventive graft polymers is particularly marked. The inventive graft polymers also have only a low content of ungrafted polyvinyl ester (B). In general, they comprise < 10% by weight, preferably < 7.5% by weight and more preferably < 5% by weight of ungrafted polyvinyl ester (B).

Owing to the low content of ungrafted polyvinyl ester and the balanced ratio of components (A) and (B), the inventive graft polymers are soluble in water or in water/alcohol mixtures (for example a 25% by weight solution of diethylene glycol monobutyl ether in water). They have pronounced, low cloud points which, for the graft polymers soluble in water at up to 50°C, are generally < 95°C, preferably < 85°C and more preferably < 75°C, and, for the other graft polymers in 25% by weight diethylene glycol monobutyl ether, generally < 90°C, preferably from 45 to 85°C.

The inventive amphiphilic graft polymers have preferably

(A) from 20 to 70% by weight of a water-soluble polyalkylene oxide as a graft base and

(B) side chains formed by free-radical polymerization of from 30 to 80% by weight of a vinyl ester component composed of

(B 1 ) from 70 to 100% by weight of vinyl acetate and/or vinyl propionate and (B2) from 0 to 30% by weight of a further ethylenically unsaturated monomer

in the presence of (A).

More preferably, they comprise from 25 to 60% by weight of the graft base (A) and from 40 to 75% by weight of the polyvinyl ester component (B).

Water-soluble polyalkylene oxides suitable for forming the graft base (A) are in princi- pie all polymers based on C2-C4-alkylene oxides which comprise at least 50% by weight, preferably at least 60% by weight, more preferably at least 75% by weight of ethylene oxide in copolymerized form.

The polyalkylene oxides (A) preferably have a low polydispersity Mw/M_n. Their polydis- persity is preferably < 1.5.

The polyalkylene oxides (A) may be the corresponding polyalkylene glycols in free form, i.e. with OH end groups, but they may also be capped at one or both end groups. Suitable end groups are, for example, Ci-C25-alkyl, phenyl and Ci-Ci4-alkylphenyl groups.

Specific examples of particularly suitable polyalkylene oxides (A) include: (A1 ) polyethylene glycols which may be capped at one or both end groups, especially by Ci-C25-alkyl groups, but are preferably not etherified, and have mean molar masses M_n of preferably from 1500 to 20 000, more preferably from 2500 to 15 000;

(A2) copolymers of ethylene oxide and propylene oxide and/or butylene oxide with an ethylene oxide content of at least 50% by weight, which may likewise be capped at one or both end groups, especially by Ci-C25-alkyl groups, but are preferably not etherified, and have mean molar masses M_n of preferably from 1500 to

20 000, more preferably from 2500 to 15 000;

(A3) chain-extended products having mean molar masses of in particular from 2500 to

20 000, which are obtainable by reacting polyethylene glycols (A1 ) having mean molar masses M_n of from 200 to 5000 or copolymers (A2) having mean molar masses M_n of from 200 to 5000 with C2-Ci2-dicarboxylic acids or -dicarboxylic esters or C6-Ci8-diisocyanates.

Preferred graft bases (A) are the polyethylene glycols (A1 ).

The side chains of the inventive graft polymers are formed by polymerization of a vinyl ester component (B) in the presence of the graft base (A).

The vinyl ester component (B) may consist advantageously of (B1 ) vinyl acetate or vinyl propionate or of mixtures of vinyl acetate and vinyl propionate, particular preference being given to vinyl acetate as the vinyl ester component (B).

However, the side chains of the graft polymer can also be formed by copolymerizing vinyl acetate and/or vinyl propionate (B 1) and a further ethylenically unsaturated monomer (B2). The fraction of monomer (B2) in the vinyl ester component (B) may be up to 30% by weight, which corresponds to a content in the graft polymer of (B2) of 24% by weight.

Suitable comonomers (B2) are, for example, monoethylenically unsaturated carboxylic acids and dicarboxylic acids and their derivatives, such as esters, amides and anhydrides, and styrene. It is of course also possible to use mixtures of different comonomers.

Specific examples include: (meth)acrylic acid, Ci-Ci2-alkyl and hydroxy-C2-Ci2-alkyl esters of (meth)acrylic acid, (meth)acrylamide, N-Ci-Ci2-alkyl(meth)acrylamide,

N,N-di(Ci-C6-alkyl)(meth)acrylamide, maleic acid, maleic anhydride and mono(Ci-Ci2- alkyl)esters of maleic acid. Preferred monomers (B2) are the Ci-Cs-alkyl esters of (meth)acrylic acid and hy- droxyethyl acrylate, particular preference being given to the Ci-C4-alkyl esters of (meth)acrylic acid.

Very particularly preferred monomers (B2) are methyl acrylate, ethyl acrylate and in particular n-butyl acrylate.

When the inventive graft polymers comprise the monomers (B2) as a constituent of the vinyl ester component (B), the content of graft polymers in (B2) is preferably from 0.5 to 20% by weight, more preferably from 1 to 15% by weight and most preferably from 2 to 10% by weight.

The inventive graft polymers are advantageously obtainable by the process which is likewise in accordance with the invention, by polymerizing a vinyl ester component (B) composed of vinyl acetate and/or vinyl propionate (B1) and, if desired, a further ethylenically unsaturated monomer (B2), in the presence of a water-soluble polyal- kylene oxide (A), a free radical-forming initiator (C) and, if desired, up to 40% by weight, based on the sum of components (A), (B) and (C), of an organic solvent (D), at a mean polymerization temperature at which the initiator (C) has a decomposition half- life of from 40 to 500 min, in such a way that the fraction of unconverted graft monomer (B) and initiator (C) in the reaction mixture is constantly kept in a quantitative deficiency relative to the polyalkylene oxide (A).

In this process, preference is given to using from 30 to 80% by weight of a vinyl ester component (B) composed of

and from 20 to 70% by weight of a water-soluble polyalkylene oxide (A) of mean molar mass M_n of from 1500 to 20 000.

The amount of initiator (C) is preferably from 0.2 to 5% by weight, in particular from 0.5 to 3.5% by weight, based in each case on component (B).

For the process according to the invention, it is essential that the steady-state concentration of radicals present at the mean polymerization temperature is substantially constant and the graft monomer (B) is present in the reaction mixture constantly only in low concentration (for example of not more than 5% by weight). This allows the reaction to be controlled, and graft polymers can be prepared in a controlled manner with the desired low degree of branching and the desired low polydispersity. The term "mean polymerization temperature" is intended to mean here that, although the process is substantially isothermal, there may, owing to the exothermicity of the reaction, be temperature variations which are preferably kept within the range of +/- 10°C, more preferably in the range of +/- 5°C.

According to the invention, the free radical-forming initiator (C) at the mean polymerization temperature should have a decomposition half-life of from 40 to 500 min, preferably from 50 to 400 min and more preferably from 60 to 300 min.

According to the invention, the initiator (C) and the graft monomer (B) are advantageously added in such a way that a low and substantially constant concentration of undecomposed initiator and graft monomer (B) is present in the reaction mixture. The proportion of undecomposed initiator in the overall reaction mixture is preferably < 15% by weight, in particular < 10% by weight, based on the total amount of initiator metered in during the monomer addition.

The mean polymerization temperature is appropriately in the range from 50 to 140°C, preferably from 60 to 120°C and more preferably from 65 to 110⁰C.

Examples of suitable initiators (C) whose decomposition half-life in the temperature range from 50 to 140°C is from 20 to 500 min are:

O-C2-Ci2-acylated derivatives of tert-C4-Ci2-alkyl hydroperoxides and tert-(Cg-Ci2- aralkyl) hydroperoxides, such as tert-butyl peroxyacetate, tert-butyl monoperoxy- maleate, tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate, tert-butyl per- oxyneoheptanoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5- trimethylhexanoate, tert-butyl peroxyneodecanoate, tert-amyl peroxypivalate, tert- amyl peroxy-2-ethylhexanoate, tert-amyl peroxyneodecanoate, 1 ,1 ,3,3-tetramethylbutyl peroxyneodecanoate, cumyl peroxyneodecanoate, tert- butyl peroxybenzoate, tert-amyl peroxybenzoate and di-tert-butyl diperoxyphtha- late; di-O-C4-Ci2-acylated derivatives of tert-Cs-Cu-alkylene bisperoxides, such as 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 2,5-dimethyl- 2,5-di(benzoylperoxy)hexane and 1 ,3-di(2-neodecanoylperoxyisopropyl)benzene; di(C2-Ci2-alkanoyl) and dibenzoyl peroxides, such as diacetyl peroxide, dipropionyl peroxide, disuccinyl peroxide, dicapryloyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, didecanoyl peroxide, dilauroyl peroxide, dibenzoyl peroxide, di(4- methylbenzoyl) peroxide, di(4-chlorobenzoyl) peroxide and di(2,4-dichlorobenzoyl) peroxide; tert-C4-C5-alkyl peroxy(C4-Ci2-alkyl)carbonates, such as tert-amyl per- oxy(2-ethylhexyl)carbonate; di(C2-Ci2-alkyl) peroxydicarbonates, such as di(n-butyl) peroxydicarbonate and di(2-ethylhexyl) peroxydicarbonate.

Depending on the mean polymerization temperature, examples of particularly suitable initiators (C) are:

at a mean polymerization temperature of from 50 to 60°C: tert-butyl peroxyneoheptanoate, tert-butyl peroxyneodecanoate, tert-amyl per- oxypivalate, tert-amyl peroxyneodecanoate, 1 ,1 ,3,3-tetramethylbutyl peroxyneode- canoate, cumyl peroxyneodecanoate, 1 ,3-di(2-neodecanoyl peroxyisopro- pyl)benzene, di(n-butyl) peroxydicarbonate and di(2-ethylhexyl) peroxydicarbonate;

at a mean polymerization temperature of from 60 to 70°C: tert-butyl peroxypivalate, tert-butyl peroxyneoheptanoate, tert-butyl peroxyneodecanoate, tert-amyl peroxypivalate and di(2,4-dichlorobenzoyl) peroxide;

at a mean polymerization temperature of from 70 to 80°C: tert-butyl peroxypivalate, tert-butyl peroxyneoheptanoate, tert-amyl peroxypivalate, dipropionyl peroxide, dicapryloyl peroxide, didecanoyl peroxide, dilauroyl peroxide, di(2,4-dichlorobenzoyl) peroxide and 2,5-dimethy[-2,5- di(2-ethy!hexanoyiperoxy)hexane;

at a mean polymerization temperature of from 80 to 90°C: tert-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-

2-ethylhexanoate, dipropionyl peroxide, dicapryloyl peroxide, didecanoyl peroxide, dilauroyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, dibenzoyl peroxide and di(4-methylbenzoyl) peroxide;

- at a mean polymerization temperature of from 90 to 100°C: tert-butyl peroxyisobutyrate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl monop- eroxymaleate, tert-amyl peroxy-2-ethylhexanoate, dibenzoyl peroxide and di(4- methylbenzoyl) peroxide;

- at a mean polymerization temperature of from 100 to 110°C: terl-buiyl monoperoxymaleate, tert-butyl peroxyisobutyrate and tert-amyl per- oxy(2-ethylhexyl)carbonate;

at a mean polymerization temperature of from 110 to 120°C: tert-butyi monoperoxymaleate, tert-butyi peroxy-3,5.5-trimethy!hexanoate and tert- amyl peroxy(2-ethylhexyl)carbonate. Preferred initiators (C) are O-C4-Ci2-acylated derivatives of tert-C4-C5-alkyl hydroperoxides, particular preference being given to tert-butyl peroxypivalate and tert-butyl per- oxy-2-ethylhexanoate.

Particularly advantageous polymerization conditions can be established effortlessly by precise adjustment of initiator (C) and polymerization temperature. For instance, the preferred mean polymerization temperature in the case of use of tert-butyl peroxypivalate is from 60 to 80°C, and, in the case of tert-butyl peroxy-2-ethylhexanoate, from 80 to 100⁰C.

The inventive polymerization reaction can be carried out in the presence of small amounts of an organic solvent (D). It is of course also possible to use mixtures of different solvents (D). Preference is given to using water-soluble or water-miscible solvents.

When a solvent (D) is used as a diluent, generally from 1 to 40% by weight, preferably from 1 to 35% by weight, more preferably from 1.5 to 30% by weight, most preferably from 2 to 25% by weight, based in each case on the sum of the components (A), (B) and (C), are used.

Examples of suitable solvents (D) include:

monohydric alcohols, preferably aliphatic Ci-Ci6-alcohols, more preferably aliphatic C2-Ci2-alcohols, most preferably C2-C4-alcohols, such as ethanol, propanol, iso- propanol, butanol, sec-butanol and tert-butanol; polyhydric alcohols, preferably C2-Cio-diols, more preferably C2-C6-diols, most preferably C2-C4-alkylene glycols, such as ethylene glycol and propylene glycol; alkylene glycol ethers, preferably alkylene glycol mono(Ci-Ci2-alkyl) ethers and alkylene glycol di(Ci-C6-alkyl) ethers, more preferably alkylene glycol mono- and di(Ci-C2-alkyl) ethers, most preferably alkylene glycol mono(Ci-C2-alkyl) ethers, such as ethylene glycol monomethyl and -ethyl ether and propylene glycol mono- methyl and -ethyl ether; polyalkylene glycols, preferably poly(C2-C4-alkylene) glycols having 2-20 C2-C4- alkylene glycol units, more preferably polyethylene glycols having 2-20 ethylene glycol units and polypropylene glycols having 2-10 propylene glycol units, most preferably polyethylene glycols having 2-15 ethylene glycol units and polypropylene glycols having 2-4 propylene glycol units, such as diethylene glycol, triethylene glycol, dipropylene glycol and tripropylene glycol; polyalkylene glycol monoethers, preferably poly(C2-C4-alkylene) glycol mono(Ci- C25-alkyl) ethers having 2-20 alkylene glycol units, more preferably poly(C2-C4- alkylene) glycol mono(Ci-C2o-alkyl) ethers having 2-20 alkylene glycol units, most preferably poly(C2-C3-alkylene) glycol mono(Ci-Ci6-alkyl) ethers having 3-20 al- kylene glycol units; carboxylic esters, preferably Ci-Cs-alkyl esters of Ci-C6-carboxylic acids, more preferably Ci-C4-alkyl esters of Ci-C3-carboxylic acids, most preferably C2-C4-alkyl esters of C2-C3-carboxylic acids, such as ethyl acetate and ethyl propionate; aliphatic ketones which preferably have from 3 to 10 carbon atoms, such as acetone, methyl ethyl ketone, diethyl ketone and cyclohexanone; cyclic ethers, in particular tetrahydrofuran and dioxane.

The solvents (D) are advantageously those solvents, which are also used to formulate the inventive graft polymers for use (for example in washing and cleaning compositions) and can therefore remain in the polymerization product.

Preferred examples of these solvents are polyethylene glycols having 2-15 ethylene glycol units, polypropylene glycols having 2-6 propylene glycol units and in particular alkoxylation products of Cδ-Cs-alcohols (alkylene glycol monoalkyl ethers and polyal- kylene glycol monoalkyl ethers).

Particular preference is given here to alkoxylation products of Cs-Ciδ-alcohols with a high degree of branching, which allow the formulation of polymer mixtures which are free-flowing at 40-70°C and have a very low polymer content at comparatively low viscosity. The branching may be present in the alkyl chain of the alcohol and/or in the polyalkoxylate moiety (copolymerization of at least one propylene oxide, butylene oxide or isobutylene oxide unit). Particularly suitable examples of these alkoxylation products are 2-ethylhexanol or 2-propylheptanol alkoxylated with 1-15 mol of ethylene oxide, C13/C15 OXO alcohol or C12/C14 or CWC-is fatty alcohol alkoxylated with 1-15 mol of ethylene oxide and 1-3 mol of propylene oxide, preference being given to 2-propylheptanol alkoxylated with 1-15 mol of ethylene oxide and 1-3 mol of propylene oxide.

In the process according to the invention, polyalkylene oxide (A), graft monomer (B1 ) and, if appropriate, (B2), initiator (C) and, if appropriate, solvent (D) are heated to the selected mean polymerization temperature in a reactor.

According to the invention, the polymerization is carried out in such a way that an ex- cess of polymer (polyalkylene oxide (A) and formed graft polymer) is constantly present in the reactor. The quantitative ratio of polymer to ungrafted monomer and initiator is generally > 10:1 , preferably > 15:1 and more preferably > 20:1.

The polymerization process according to the invention can in principle be carried out in various reactor types. The reactor used is preferably a stirred tank in which the polyalkylene oxide (A), if appropriate together with portions, of generally up to 15% by weight of the particular total amount, of graft monomers (B), initiator (C) and solvent (D), are initially charged fully or partly and heated to the polymerization temperature, and the remaining amounts of (B), (C) and, if appropriate, (D) are metered in, preferably separately. The remaining amounts of (B), (C) and, if appropriate, (D) are metered in preferably over a period of > 2 h, more preferably of > 4 h and most preferably of > 5 h.

In the case of the particularly preferred, substantially solvent-free process variant, the entire amount of polyalkylene oxide (A) is initially charged as a melt and the graft monomers (B1 ) and, if appropriate, (B2), and also the initiator (C) present preferably in the form of a from 10 to 50% by weight solution in one of the solvents (D), are metered in, the temperature being controlled such that the selected polymerization temperature, on average during the polymerization, is maintained with a range of especially +/- 10°C, in particular +/- 5°C.

In a further particularly preferred, low-solvent process variant, the procedure is as described above, except that solvent (D) is metered in during the polymerization in order to limit the viscosity of the reaction mixture. It is also possible to commence with the metered addition of the solvent only at a later time with advanced polymerization, or to add it in portions.

The polymerization can be effected under standard pressure or at reduced or elevated pressure. When the boiling point of the monomers (B) or of any diluent (D) used is ex- ceeded at the selected pressure, the polymerization is carried out with reflux cooling.

Owing to their marked amphiphilic character, the inventive graft polymers have particularly favorable interface properties. They can be used advantageously in washing and cleaning compositions, where they support the removal of hydrophobic soils from tex- tile or hard surfaces by the surfactants and thus improve the washing and cleaning performances of the formulations. Moreover, they bring about better dispersion of the removed soil in the washing or cleaning liquor and prevent its redeposition onto the surfaces of the washed or cleaned materials.

Laundry Detergents and Cleaning Compositions

The inventive laundry detergents and cleaning compositions of the present invention comprise generally from 0.05 to 10% by weight, preferably from 0.1 to 5% by weight and more preferably from 0.25 to 2.5% by weight, based on the particular overall com- position, of the amphiphilic graft polymers of the present invention. In addition, the laundry detergents and cleaning compositions generally comprise surfactants and, if appropriate, other polymers as washing substances, builders and further customary ingredients, for example cobuilders, complexing agents, bleaches, standardizers, graying inhibitors, dye transfer inhibitors, enzymes and perfumes.

The amphiphilic graft polymers of the present invention may be utilized in laundry detergents or cleaning compositions comprising a surfactant system comprising C10-C15 alkyl benzene sulfonates (LAS) and one or more co-surfactants selected from nonionic, cationic, anionic or mixtures thereof. The selection of co-surfactant may be dependent upon the desired benefit. In one embodiment, the co-surfactant is selected as a non- ionic surfactant, preferably C12-C18 alkyl ethoxylates. In another embodiment, the co- surfactant is selected as an anionic surfactant, preferably C10-C18 alkyl alkoxy sulfates (AE_xS) wherein x is from 1-30. In another embodiment the co-surfactant is selected as a cationic surfactant, preferably dimethyl hydroxyethyl lauryl ammonium chloride. If the surfactant system comprises C10-C15 alkyl benzene sulfonates (LAS), the LAS is used at levels ranging from about 9% to about 25%, or from about 13% to about 25%, or from about 15% to about 23% by weight of the composition.

The surfactant system may comprise from 0% to about 7%, or from about 0.1 % to a- bout 5%, or from about 1 % to about 4% by weight of the composition of a co-surfactant selected from a nonionic co-surfactant, cationic co-surfactant, anionic co-surfactant and any mixture thereof.

Non-limiting examples of nonionic co-surfactants include: C12-C18 alkyl ethoxylates, such as, NEODOL® nonionic surfactants from Shell; C6-C12 alkyl phenol alkoxylates wherein the alkoxylate units are a mixture of ethyleneoxy and propyleneoxy units; C12- C18 alcohol and C6-C12 alkyl phenol condensates with ethylene oxide/propylene oxide block alkyl polyamine ethoxylates such as PLURONIC® from BASF; C14-C22 mid-chain branched alcohols, BA, as discussed in US 6,150,322; C14-C22 mid-chain branched alkyl alkoxylates, BAE_x, wherein x is from 1-30, as discussed in US 6,153,577, US 6,020,303 and US 6,093,856; Alkylpolysaccharides as discussed in U.S. 4,565,647 Llenado, issued January 26, 1986; specifically alkylpolyglycosides as discussed in US 4,483,780 and US 4,483,779; Polyhydroxy fatty acid amides as discussed in US 5,332,528; and ether capped poly(oxyalkylated) alcohol surfactants as discussed in US 6,482,994 and WO 01/42408.

Non-limiting examples of semi-polar nonionic co-surfactants include: water-soluble a- mine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl moieties and hydroxyalkyl moieties containing from about 1 to about 3 carbon atoms; water-soluble phosphine oxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and 2 moieties selected from the group consisting of alkyl moieties and hydroxyalkyl moieties containing from about 1 to about 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to about 18 carbon atoms and a moiety selected from the group consisting of alkyl moieties and hydroxyalkyl moieties of from about 1 to about 3 carbon atoms. See WO 01/32816, US 4,681 ,704, and US 4,133,779.

Non-limiting examples of cationic co-surfactants include: the quaternary ammonium surfactants, which can have up to 26 carbon atoms include: alkoxylate quaternary ammonium (AQA) surfactants as discussed in US 6,136,769; dimethyl hydroxyethyl quaternary ammonium as discussed in 6,004,922; dimethyl hydroxyethyl lauryl ammonium chloride; polyamine cationic surfactants as discussed in WO 98/35002, WO 98/35003, WO 98/35004, WO 98/35005, and WO 98/35006; cationic ester surfactants as discussed in US Patents Nos. 4,228,042, 4,239,660 4,260,529 and US 6,022,844; and amino surfactants as discussed in US 6,221 ,825 and WO 00/47708, specifically amido propyldimethyl amine (APA).

Nonlimiting examples of anionic co-surfactants useful herein include: C10-C20 primary, branched chain and random alkyl sulfates (AS); C10-C18 secondary (2,3) alkyl sulfates; C10-C18 alkyl alkoxy sulfates (AE_xS) wherein x is from 1-30; C10-C18 alkyl alkoxy car- boxylates comprising 1-5 ethoxy units; mid-chain branched alkyl sulfates as discussed in US 6,020,303 and US 6,060,443; mid-chain branched alkyl alkoxy sulfates as discussed in US 6,008,181 and US 6,020,303; modified alkylbenzene sulfonate (MLAS) as discussed in WO 99/05243, WO 99/05242 and WO 99/05244; methyl ester sulfonate (MES); and alpha-olefin sulfonate (AOS).

The present invention may also relates to compositions comprising the inventive am- phiphilic graft polymers and a surfactant system comprising Cs-C-is linear alkyl sulpho- nate surfactant and a co-surfactant. The compositions can be in any form, namely, in the form of a liquid; a solid such as a powder, granules, agglomerate, paste, tablet, pouches, bar, gel; an emulsion; types delivered in dual-compartment containers; a spray or foam detergent; premoistened wipes (i.e., the cleaning composition in combination with a nonwoven material such as that discussed in US 6,121 ,165, Mackey, et al.); dry wipes (i.e., the cleaning composition in combination with a nonwoven materials, such as that discussed in US 5,980,931 , Fowler, et al.) activated with water by a consumer; and other homogeneous or multiphase consumer cleaning product forms.

In one embodiment, the cleaning composition of the present invention is a liquid or solid laundry detergent composition. In another embodiment, the cleaning composition of the present invention is a hard surface cleaning composition, preferably wherein the hard surface cleaning composition impregnates a nonwoven substrate. As used herein "impregnate" means that the hard surface cleaning composition is placed in contact with a nonwoven substrate such that at least a portion of the nonwoven substrate is penetrated by the hard surface cleaning composition, preferably the hard surface cleaning composition saturates the nonwoven substrate. The cleaning composition may also be utilized in car care compositions, for cleaning various surfaces such as hard wood, tile, ceramic, plastic, leather, metal, glass. This cleaning composition could be also designed to be used in a personal care and pet care compositions such as shampoo composition, body wash, liquid or solid soap and other cleaning composition in which surfactant comes into contact with free hardness and in all compositions that require hardness tolerant surfactant system, such as oil drilling compositions.

In another embodiment the cleaning composition is a dish cleaning composition, such as liquid hand dishwashing compositions, solid automatic dishwashing compositions, liquid automatic dishwashing compositions, and tab/unit does forms of automatic dishwashing compositions.

Quite typically, cleaning compositions herein such as laundry detergents, laundry de- tergent additives, hard surface cleaners, synthetic and soap-based laundry bars, fabric softeners and fabric treatment liquids, solids and treatment articles of all kinds will require several adjuncts, though certain simply formulated products, such as bleach additives, may require only, for example, an oxygen bleaching agent and a surfactant as described herein. A comprehensive list of suitable laundry or cleaning adjunct materi- als can be found in WO 99/05242.

Common cleaning adjuncts include builders, enzymes, polymers not discussed above, bleaches, bleach activators, catalytic materials and the like excluding any materials already defined hereinabove. Other cleaning adjuncts herein can include suds boost- ers, suds suppressors (antifoams) and the like, diverse active ingredients or specialized materials such as dispersant polymers (e.g., from BASF Corp. or Rohm & Haas) other than those described above, color speckles, silvercare, anti-tarnish and/or anti- corrosion agents, dyes, fillers, germicides, alkalinity sources, hydrotropes, antioxidants, enzyme stabilizing agents, pro-perfumes, perfumes, solubilizing agents, car- riers, processing aids, pigments, and, for liquid formulations, solvents, chelating a- gents, dye transfer inhibiting agents, dispersants, brighteners, suds suppressors, dyes, structure elasticizing agents, fabric softeners, anti-abrasion agents, hydrotropes, processing aids, and other fabric care agents, surface and skin care agents. Suitable examples of such other cleaning adjuncts and levels of use are found in U.S. Patent Nos. 5,576,282, 6,306,812 B1 and 6,326,348 B1.

Method of Use

The present invention includes a method for cleaning a targeted surface. As used herein "targeted surface" may include such surfaces such as fabric, dishes, glasses, and other cooking surfaces, hard surfaces, hair or skin. As used herein "hard surface" includes hard surfaces being found in a typical home such as hard wood, tile, ceramic, plastic, leather, metal, glass. Such method includes the steps of contacting the com- position comprising the modified polyol compound, in neat form or diluted in wash liquor, with at least a portion of a targeted surface then optionally rinsing the targeted surface. Preferably the targeted surface is subjected to a washing step prior to the aforementioned optional rinsing step. For purposes of the present invention, washing includes, but is not limited to, scrubbing, wiping and mechanical agitation.

As will be appreciated by one skilled in the art, the cleaning compositions of the present invention are ideally suited for use in home care (hard surface cleaning compositions) and/or laundry applications.

The composition solution pH is chosen to be the most complimentary to a target surface to be cleaned spanning broad range of pH, from about 5 to about 11. For personal care such as skin and hair cleaning pH of such composition preferably has a pH from about 5 to about 8 for laundry cleaning compositions pH of from about 8 to about 10. The compositions are preferably employed at concentrations of from about 200 ppm to about 10,000 ppm in solution. The water temperatures preferably range from about 5 ⁰C to about 100 ⁰C.

For use in laundry cleaning compositions, the compositions are preferably employed at concentrations from about 200 ppm to about 10000 ppm in solution (or wash liquor). The water temperatures preferably range from about 5⁰C to about 6O⁰C. The water to fabric ratio is preferably from about 1 :1 to about 20:1.

The method may include the step of contacting a nonwoven substrate impregnated with an embodiment of the composition of the present invention As used herein "non- woven substrate" can comprise any conventionally fashioned nonwoven sheet or web having suitable basis weight, caliper (thickness), absorbency and strength characteristics. Examples of suitable commercially available nonwoven substrates include those marketed under the tradename SONTARA® by DuPont and POLYWEB® by James River Corp.

As will be appreciated by one skilled in the art, the cleaning compositions of the present invention are ideally suited for use in liquid dish cleaning compositions. The method for using a liquid dish composition of the present invention comprises the steps of contacting soiled dishes with an effective amount, typically from about 0.5 ml. to about 20 ml. (per 25 dishes being treated) of the liquid dish cleaning composition of the present invention diluted in water. Examples

Preparation of inventive graft polymers

The K values reported below were measured in 3% by weight aqueous NaCI solution at 23°C and a polymer concentration of 1 % by weight.

The mean molar masses and polydispersities were determined by gel permeation chromatography using a 0.5% by weight LiBr solution in dimethylacetamide as the elu- ent and of polymethyl methacrylate (PMMA) as the standard.

The degrees of branching were determined by ¹³C NMR spectroscopy in deuterated dimethyl sulfoxide from the integrals of the signals of the graft sites and the -Chfe- groups of the polyethylene glycol. The values reported relate to all of the polyethylene glycol present in the product, i.e. including ungrafted polyethylene glycol, and correspond to the number of side chains present on average per polyethylene glycol.

Graft polymer 1

A polymerization vessel equipped with stirrer and reflux condenser was initially charged with 480 g of polyethylene glycol (M_n 12 000) under a nitrogen atmosphere and melted at 70⁰C.

After addition of 16.0 g of vinyl acetate and 0.2 g of tert-butyl peroxypivalate, dissolved in 0.9 g of dipropylene glycol, and stirring for a further 5 minutes, 304 g of vinyl acetate within 6 h (feed 1) and 4.0 g of tert-butyl peroxypivalate, dissolved in 18 g of dipropylene glycol, within 7 h (feed 2) were metered in in parallel continuously with constant flow rates at internal temperature 70°C with stirring.

After feed 2 had ended and the mixture had been stirred at 70°C for a further hour, 4.8 g of tert-butyl peroxypivalate, dissolved in 9.0 g of dipropylene glycol, were added in 3 portions at 70°C with further stirring for two hours in each case. In addition, 73 g of dipropylene glycol were added to lower the viscosity.

Residual amounts of vinyl acetate were removed by vacuum distillation at 70°C. Subsequently, a solids content of 24.3% by weight was established by adding water.

The resulting graft polymer had a K value of 28.4, a polydispersity of 1.8 (M_w 36 900, M_n 21 000) and a degree of branching of 0.8% (corresponds to 0.15 graft site/50 EO units). Graft polymer 2

A polymerization vessel equipped with stirrer and reflux condenser was initially charged with 400 g of polyethylene glycol (M_n 9000) under a nitrogen atmosphere and melted at 85°C.

After addition of 20.0 g of vinyl acetate and 0.25 g of tert-butyl peroxy-2-ethyl- hexanoate, dissolved in 0.9 g of dipropylene glycol, and stirring for a further 5 minutes, 380 g of vinyl acetate within 6 h (feed 1) and 5.0 g of tert-butyl peroxy-2-ethyl- hexanoate, dissolved in 18 g of dipropylene glycol, within 7 h (feed 2) were metered in in parallel continuously with constant flow rates at internal temperature 85°C with stirring.

After feed 2 had ended and the mixture had been stirred at 85°C for a further hour, 6.0 g of tert-butyl peroxy-2-ethylhexanoate, dissolved in 9.0 g of dipropylene glycol, were added in 3 portions at 85°C with further stirring for two hours in each case. In addition, 73 g of dipropylene glycol were added to lower the viscosity.

Residual amounts of vinyl acetate were removed by vacuum distillation at 85°C. Sub- sequently, a solids content of 23.2% by weight was established by adding water.

The resulting graft polymer had a K value of 24.0, a polydispersity of 1.9 (M_w 37 000, M_n 19 500) and a degree of branching of 0.8% (corresponds to 0.20 graft site/50 EO units).

Graft polymer 3

A polymerization pressure vessel equipped with stirrer and reflux condenser was initially charged with 1000 g of polyethylene glycol (M_n 6000) under a nitrogen atmos- phere and melted at 90°C.

Then, 1500 g of vinyl acetate within 6 h (feed 1) and 14.5 g of tert-butyl peroxy-2-ethyl- hexanoate, dissolved in 60.5 g of tripropylene glycol, within 7 h (feed 2) were metered in in parallel continuously with constant flow rates at internal temperature 90°C with stirring.

After feed 2 had ended and the mixture had been stirred at 90°C for a further hour, 17.1 g of tert-butyl peroxy-2-ethylhexanoate, dissolved in 22.6 g of tripropylene glycol, were added in 3 portions at 90°C with further stirring for two hours in each case. In ad- dition, 73 g of dipropylene glycol were added to lower the viscosity. Residual amounts of vinyl acetate were removed by vacuum distillation at 90°C. Subsequently, a solids content of 22.8% by weight was established by adding water.

The resulting graft polymer had a K value of 19.6, a polydispersity of 1.9 (M_w 35 700, M_n 18 800) and a degree of branching of 0.9% (corresponds to 0.33 graft site/50 EO units).

Graft polymer 4

After addition of 14.0 g of vinyl acetate, 1.6 g of butyl acrylate and 0.3 g of tert-butyl peroxypivalate, dissolved in 0.9 g of dipropylene glycol, and stirring for a further 5 minutes, 274 g of vinyl acetate within 6 h (feed 1) , 30.4 g of butyl acrylate within 6 h (feed 2) and 6.0 g of tert-butyl peroxypivalate, dissolved in 18 g of dipropylene glycol, within 7 h (feed 3) were metered in in parallel continuously with constant flow rates at internal temperature 70°C with stirring.

After feed 3 had ended and the mixture had been stirred at 70°C for a further hour, 7.2 g of tert-butyl peroxypivalate, dissolved in 9.0 g of dipropylene glycol, were added in 3 portions at 70°C with further stirring for two hours in each case. In addition, 73 g of dipropylene glycol were added to lower the viscosity.

Residual amounts of monomer were removed by vacuum distillation at 70°C. Subsequently, a solids content of 19.8% by weight was established by adding water.

The resulting graft polymer had a K value of 29.1 , a polydispersity of 1.9 (M_w 35 500, Mn 18 400) and a degree of branching of 0.7% (corresponds to 0.13 graft site/50 EO units).

Graft polymer 5

A polymerization pressure vessel equipped with stirrer and reflux condenser was initially charged with 1 175 g of polyethylene glycol (M_n 4000) under a nitrogen atmosphere and melted at 90°C.

After addition of 88.0 g of vinyl acetate and 0.85 g of tert-butyl peroxy-2-ethyl- hexanoate, dissolved in 3.5 g of tripropylene glycol, and stirring for a further 5 minutes, 1674 g of vinyl acetate within 6 h (feed 1) and 17.0 g of tert-butyl peroxy-2-ethyl- hexanoate, dissolved in 71 g of tripropylene glycol, within 7 h (feed 2) were metered in in parallel continuously with constant flow rates at internal temperature 90°C with stirring.

After feed 2 had ended and the mixture had been stirred at 90°C for a further hour, 39.0 g of tert-butyl peroxy-2-ethylhexanoate, dissolved in 21.0 g of tripropylene glycol, were added in 3 portions at 70°C with further stirring for two hours in each case. In addition, 73 g of dipropylene glycol were added to lower the viscosity.

Residual amounts of vinyl acetate were removed by vacuum distillation at 90°C. Sub- sequently, a solids content of 23.4% by weight was established by adding water.

The resulting graft polymer had a K value of 17.9, a polydispersity of 2.3 (M_w 26 800, Mn 1 1 700) and a degree of branching of 0.6% (corresponds to 0.33 graft site/50 EO units).

Graft polymer 6

A polymerization pressure vessel equipped with stirrer and reflux condenser was initially charged with 444 g of polyethylene glycol (M_n 6000) under a nitrogen atmosphere and melted at 90⁰C.

After addition of 0.55 g of tert-butyl per-2-ethylhexanoate, dissolved in 1.7 g of tripropylene glycol, and stirring for a further 15 minutes, 666 g of vinyl acetate within 6 h (feed 1 ) and 7.22 g of tert-butyl peroxy-2-ethylhexanoate, dissolved in 21.6 g of tripropylene glycol, within 6.5 h (feed 2), and also, beginning 3 h after the start of feed 1 , 233 g of alkoxylated 2-propylheptanol (1 mol of PO and 10 mol of EO/mol) within 3.5 h (feed 3) were metered in in parallel continuously with constant flow rates at internal temperature 90°C with stirring.

After the end of feeds 2 and 3 and subsequent stirring at 90°C for a further hour, 6.1 g of tert-butyl peroxy-2-ethylhexanoate, dissolved in 18.25 g of tripropylene glycol, were added in 3 portions at 90°C with further stirring for two hours in each case.

Residue amounts of vinyl acetate were removed by vacuum distillation at 90°C. Sub- sequently, a solids content of 86.9% by weight was established by adding water.

The resulting graft polymer had a K value of 17.6, a polydispersity of 1.8 (M_w 35 700, M_n 20 000) and a degree of branching of 0.9% (corresponds to 0.33 graft site/50 EO units). Composition Formulations

Example 7 - Granular Laundry Detergent

¹ An amphiphilic graft polymer or any mixture of polymers according to any of Examples 1 , 2, 3, 4, 5 or 6.

Example 8 - Granular Laundry Detergent Aqueous slurry composition.

¹ An amphiphilic graft polymer or any mixture of polymers according to any of Examples 1 , 2, 3, 4, 5 or 6. Preparation of a spray-dried powder.

An aqueous slurry having the composition as described above is prepared having a moisture content of 25.89%. The aqueous slurry is heated to 72⁰C and pumped under high pressure (from 5.5x10⁶Nm"² to 6.OxIO⁶Nm"²), into a counter current spray-drying tower with an air inlet temperature of from 27O⁰C to 300⁰C. The aqueous slurry is atomised and the atomised slurry is dried to produce a solid mixture, which is then cooled and sieved to remove oversize material (>1.8mm) to form a spray-dried powder, which is free-flowing. Fine material (<0.15mm) is elutriated with the exhaust the exhaust air in the spray-drying tower and collected in a post tower containment system. The spray- dried powder has a moisture content of 1.0wt%, a bulk density of 427g/l and a particle size distribution such that 95.2wt% of the spray-dried powder has a particle size of from 150 to 710 micrometers. The composition of the spray-dried powder is given below. Spray-dried powder composition.

Preparation of an anionic surfactant particle 1

The anionic detersive surfactant particle 1 is made on a 52Og batch basis using a TiIt- A-Pin then Tilt-A-Plow mixer (both made by Processall). 108g sodium sulphate sup- plied is added to the Tilt-A-Pin mixer along with 244g sodium carbonate. 168g of 70% active C25E3S paste (sodium ethoxy sulphate based on C12/15 alcohol and ethylene oxide) is added to the Tilt-A-Pin mixer. The components are then mixed at 1200rpm for 10 seconds. The resulting powder is then transferred into a Tilt-A-Plow mixer and mixed at 200rpm for 2 minutes to form particles. The particles are then dried in a fluid bed dryer at a rate of 2500l/min at 12O⁰C until the equilibrium relative humidity of the particles is less than 15%. The dried particles are then sieved and the fraction through 1 180μm and on 250μm is retained The composition of the anionic detersive surfactant particle 1 is as follows: 25.0%w/w C25E3S sodium ethoxy sulphate 18.0%w/w sodium sulphate 57.0%w/w sodium carbonate

Preparation of a cationic detersive surfactant particle 1

The cationic surfactant particle 1 is made on a 14.6kg batch basis on a Morton FM-50 Loedige mixer. 4.5kg of micronised sodium sulphate and 4.5kg micronised sodium car- bonate are premixed in the Morton FM-50 Loedige mixer. 4.6kg of 40% active mono- C12-14 alkyl mono-hydroxyethyl di-methyl quaternary ammonium chloride (cationic surfactant) aqueous solution is added to the Morton FM-50 Loedige mixer whilst both the main drive and the chopper are operating. After approximately two minutes of mixing, a 1.Okg 1 :1 weight ratio mix of micronised sodium sulphate and micronised sodium car- bonate is added to the mixer. The resulting agglomerate is collected and dried using a fluid bed dryer on a basis of 2500l/min air at 100-140⁰C for 30 minutes. The resulting powder is sieved and the fraction through 1400μm is collected as the cationic surfactant particle 1. The composition of the cationic surfactant particle 1 is as follows: 15 %w/w mono-Ci2-i4 alkyl mono-hydroxyethyl di-methyl quaternary ammonium chloride

40.76%w/w sodium carbonate 40.76%w/w sodium sulphate 3.48%w/w moisture and miscellaneous Preparation of a granular laundry detergent composition

10.84kg of the spray-dried powder of example 1 , 4.76kg of the anionic detersive surfactant particle 1 , 1.57kg of the cationic detersive surfactant particle 1 and 7.83kg (total amount) of other individually dosed dry-added material are dosed into a i m diameter concrete batch mixer operating at 24rpm. Once all of the materials are dosed into the mixer, the mixture is mixed for 5 minutes to form a granular laundry detergent composition. The formulation of the granular laundry detergent composition is described below: A granular laundry detergent composition.

Example 9 - Liquid Laundry Detergent

Ingredient A B E F⁵

² diethylenetriaminepentaacetic acid, sodium salt

³ diethylenetriaminepentakismethylenephosphonic acid, sodium salt

⁴ ethylenediaminetetraacetic acid, sodium salt

⁵ Acusol OP 301 Example 10 - Liquid Dish Handwashing Detergents

² Nonionic may be either Cu Alkyl ethoxylated surfactant containing 9 ethoxy groups. ³ 1 ,3, BAC is 1 ,3 bis(methylamine)-cyclohexane.

⁴ (N,N-dimethylamino)ethyl methacrylate homopolymer

Example 11 - Automatic Dishwasher Detergent

² Such as ACUSOL® 445N available from Rohm & Haas or ALCOSPERSE® from Alco.

³ such as SLF-18 POLY TERGENT from the ONn Corporation. Unless otherwise noted, all component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources.

All percentages and ratios are calculated by weight unless otherwise indicated. All percentages and ratios are calculated based on the total composition unless otherwise indicated.

Claims

What is claimed is:

1. An amphiphilic graft polymer based on water-soluble polyalkylene oxides (A) as a graft base and side chains formed by polymerization of a vinyl ester component (B), said polymer having an average of < 1 graft site per 50 alkylene oxide units and mean molar masses M_w of from 3000 to 100 000.

2. The graft polymer according to claim 1 which has a polydispersity M_w/Mn of < 3.

3. The graft polymer according to claim 1 or 2 which comprises < 10% by weight of polyvinyl ester (B) in ungrafted form.

4. The graft polymer according to claims 1 to 3 which has

(B1 ) from 70 to 100% by weight of vinyl acetate and/or vinyl propionate and

(B2) from 0 to 30% by weight of a further ethylenically unsaturated monomer

in the presence of (A).

5. The graft polymer according to claims 1 to 4 which comprises from 25 to 60% by weight of the graft base (A) and from 40 to 75% by weight of the vinyl ester com- ponent (B).

6. The graft polymer according to claims 1 to 5 in which the vinyl ester component (B) comprises from 70 to 100% by weight of vinyl acetate (B1 ) and from 0 to 30% by weight of a Ci-Cs-alkyl acrylate (B2).

7. An amphiphilic graft polymer obtainable by free-radical polymerization of

(B) from 30 to 80% by weight of a vinyl ester component composed of

(B1 ) from 70 to 100% by weight of vinyl acetate and/or vinyl propionate and

(B2) from 0 to 30% by weight of a further ethylenically unsaturated monomer,

in the presence of (A) from 20 to 70% by weight of a water-soluble polyalkylene oxide of mean molar mass M_n of from 1500 to 20 000,

(C) from 0.25 to 5% by weight, based on component (B), of a free radical- forming initiator

and

(D) from 0 to 40% by weight, based on the sum of components (A), (B) and (C), of an organic solvent

at a mean polymerization temperature at which the initiator (C) has a decomposition half-life of from 40 to 500 min, is polymerized in such a way that the fraction of unconverted graft monomer (B) and initiator (C) in the reaction mixture is constantly kept in a quantitative deficiency relative to the polyalkylene oxide (A).

9. A process for preparing graft polymers according to claims 1 to 8, which comprises polymerizing a vinyl ester component (B) composed of vinyl acetate and/or vinyl propionate (B1) and, if desired, a further ethylenically unsaturated monomer

(B2), in the presence of a water-soluble polyalkylene oxide (A), a free radical- forming initiator (C) and, if desired, up to 40% by weight, based on the sum of components (A), (B) and (C), of an organic solvent (D), at a mean polymerization temperature at which the initiator (C) has a decomposition half-life of from 40 to 500 min, in such a way that the fraction of unconverted graft monomer (B) and initiator (C) in the reaction mixture is constantly kept in a quantitative deficiency relative to the polyalkylene oxide (A).

10. The process according to claim 9, wherein

(B) from 30 to 80% by weight of a vinyl ester component composed of

(B 1 ) from 70 to 100% by weight of vinyl acetate and/or vinyl propionate and (B2) from 0 to 30% by weight of a further ethylenically unsaturated monomer are polymerized

in the presence of

(A) from 20 to 70% by weight of a water-soluble polyalkylene oxide of mean molar mass M_n of from 1500 to 20 000, (C) from 0.25 to 5% by weight, based on component (B), of a free radical- forming initiator

and

(D) from 0 to 40% by weight, based on the sum of components (A), (B) and (C), of an organic solvent.

1 1. The process according to claim 9 or 10, wherein vinyl acetate and/or vinyl propi- onate (B1) and, if desired, the further ethylenically unsaturated monomer (B2) and the initiator (C) are metered into a melt of polyalkylene oxide (A).

12. The process according to claims 9 to 1 1 , wherein the polymerization is undertaken at from 60 to 120°C.

13. The process according to claims 9 to 12, wherein the initiator (C) used is a tert- C4-C5-alkyl ester of aliphatic per-C4-Ci2-carboxylic acids.