EP0866879A1

EP0866879A1 - Use of aqueous solutions or dispersions of copolymers of carboxyl-group-containing monomers, ethylenically unsaturated acetals, cetals or orthocarboxylic acid esters and optionally other copolymerisable monomers as leather tanning agents

Info

Publication number: EP0866879A1
Application number: EP96942289A
Authority: EP
Inventors: Walter Denzinger; Axel Kistenmacher; Gerhard Wolf; Michael Kneip; Norbert Greif; Knut Oppenländer
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1995-12-12
Filing date: 1996-12-02
Publication date: 1998-09-30
Also published as: WO1997021839A1; US6033442A; AU1139897A; DE19546254A1

Abstract

Copolymers of (A) 5 to 95 mol % of ethylenically unsaturated monocarboxylic acids or dicarboxylic acids with 3 to 10 C-atoms, their anhydrides, their alkali metal salts, alkaline earth metal salts or ammonium salts or mixtures thereof; (B) 5 to 95 mol % of ethylenically unsaturated acetals, cetals or orthocarboxylic acid esters of the general formula (I), in which the variables have the following meanings: R?1 to R12¿ are, independently of each other, hydrogen or an organic radical and a to d are, independently of each other, 0 or 1; and (C) 0 to 70 mol % of other copolymerisable monomers. The invention relates to the use of aqueous solutions or dispersions of said copolymers or hydrolysis products or polymeric analogous reaction products of said copolymers as tanning agents for single tannage, pre-tannage and co-tannage of dehaired skins and hides, and retannage of leather and skins.

Description

7/21839 PCIYEP96 / 05318

Use of aqueous solutions or dispersions of copolymers of monomers containing carboxyl groups, ethylenically unsaturated acetals, ketals or orthocarboxylic acid esters and optionally other copolymerizable monomers as leather tanning agents

description

The present invention relates to the use of aqueous solutions or dispersions of copolymers of monomers containing carboxyl groups, ethylenically unsaturated cyclic or semicyclic acetals, ketals or orthocarboxylic acid esters and optionally other copolymerizable monomers as leather tanning agents. Because part of this

Copolymers represents new substances, the invention further relates to these copolymers.

In leather production, the main tanning is usually done with mineral tanning agents such as basic chrome,

Aluminum and / or zirconium salts carried out alone or in combination with synthetic tanning agents. Subsequent retanning with natural or synthetic tanning agents serves to improve leather properties such as feel, softness, grain and fullness.

Syntans, i.e. water-soluble condensation products from e.g. Naphthalenesulfonic acid and formaldehyde or from phenolsulfonic acid, formaldehyde and urea, also lignosulfonic acids and also polymers and copolymers based on acrylic acid and other unsaturated polymerizable carboxylic acid, generally in combination with the aforementioned syntanes.

For example, in US-A 2 205 882 (1) and US-A 2 205 883 (2) the use of polyacrylic acid, of copolymers of acrylic and methacrylic acid, of styrene-maleic anhydride copolymers, of polymethacrylic acid and of copolymers of Methacrylic acid with styrene or methyl methacrylate for tanning leather described. A disadvantage of these products is that the desired softness and fullness can often not be achieved. Furthermore, these products generally lighten the color. In addition, it can be observed that such product only in a limited concentration when retanning

I.

Leather can be used, since higher amounts are used the leather hardens, which can lead to scar fracture.

The known polymeric retanning agents for leather are still in need of improvement with regard to their fullness and softness, which they lend to the leather, and in terms of their dyeing behavior. The object of the present invention was therefore to provide such retanning agents with corresponding improved properties.

Accordingly, the use of aqueous solutions or dispersions of copolymers

A) 5 to 95 mol% of ethylenically unsaturated mono- or dicarboxylic acids with 3 to 10 carbon atoms, their anhydrides, their alkali metal, alkaline earth metal or ammonium salts or mixtures thereof,

B) 5 to 95 mol% of ethylenically unsaturated acetals, ketals or orthocarboxylic acid esters of the general formula I

in which the variables have the following meaning

R ^ R ^{2 are} independently hydrogen,

Cx- to Cir _j -alkyl, Ci- to C] _o-alkoxy, amino, Cx- to C ₄ -alkylamino or di-C ₃ - to C ₄ -alkylamino,

R ^3, R ^4, R ^5, R ^6, R ^8, R ^9, R ^10, R ⁿ are independently hydrogen ^¬ material, Ci- to C ₁₀ alkoxy, amino, Ci to C ₄ alkylamino, di-Cj .- to C ₄ alkylamino, C _ß - to C ₁₄ aryl, C ₇ - to C ₁₈ aralkyl, carboxyl, Ci to C ₂₀ alkoxycarbonyl, C ₂ interrupted by one to five non-adjacent oxygen atoms - to -C ₈ alkyl or sulfo or phosphono groups,

R ^{7 is} hydrogen, C _x - to Cι ₀ alkyl, C ₆ - to Cι ₄ aryl, C ₇ - to Cι ₈ aralkyl or

Ci to Cio acyl, Ri2 hydrogen, Ci- to C_o-alkyl,

Ci to Cio alkoxy, hydroxyl or Ci to Cio acyloxy and

a, b, c, d independently of one another the number 0 or 1, where

R ² and R ⁴ together also represent a 1,3- or 1,4-alkylene group with 3 to 12 carbon atoms and

R ⁵ and R ⁷ together can also form a 1,2- or 1,3-alkylene group having 2 to 12 carbon atoms, and

C) 0 to 70 mol% of further copolymerizable monomers

or their hydrolysis products or polymer-analogous reaction products have been found as tanning agents for single tanning, pretanning and tanning of the bare and fur bare and for retanning leather and fur.

Suitable carboxyl group-containing monomers of group A are, in particular, monoethylenically unsaturated mono- or dicarboxylic acids or their corresponding anhydrides with 3 to 6 carbon atoms, such as e.g. Acrylic acid, methacrylic acid, ethyl acrylic acid, allyl acetic acid, crotonic acid, vinyl acetic acid, maleic acid, maleic acid monoalkyl ester, itaconic acid, mesaconic acid, fumaric acid, citraconic acid, methylene malonic acid and their alkali metal, alkaline earth metal or ammonium salts and mixtures thereof. In the case of dicarboxylic acid monoalkyl esters, the number of carbon atoms given relates to the dicarboxylic acid skeleton; the alkyl group in the ester radical can independently have 1 to 20 carbon atoms, in particular 1 to 8 carbon atoms. The corresponding monoethylenically unsaturated dicarboxylic anhydrides are maleic anhydride, itaconic anhydride, citraconic anhydride or their

Mixtures into consideration. Acrylic acid, methacrylic acid, maleic acid itaconic acid and maleic anhydride are preferred. The group B monomers are monoethylenically unsaturated acetals, ketals or orthocarboxylic acid esters with a cyclic or semicyclic structure.

The variables R ¹ and R ² are preferably independently of one another, hydrogen, Ci to _C4 alkyl, especially methyl and ethyl, Ci to C ₄ alkoxy, especially methoxy and ethoxy, N- (Cι- to _C4 alkyl ) ammo, especially N-methylammo and N-ethylamino, and N, N- (di-C 1 -C ₄ -alkyl) amino, in particular N, N-dimethylamino and N, N-diethylamino.

The variables R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ preferably independently denote hydrogen, C 1 -C ₄ -alkyl, in particular methyl and ethyl, C 1 -C ₄ -alkoxy, in particular methoxy and ethoxy, N- (C 1 -C ₄ -alkyl) amino, in particular N-methylamino and N-ethylamino, N, N- (di-C 1 -C ₄ -alkyl) amino, in particular N , N-dimethylamino and N, N-diethylamino, phenyl, tolyl, benzyl, carboxyl,

Ci to C ₄ alkoxycarbonyl, especially methoxycarbonyl and ethoxycarbonyl, and groupings of the formula -CH ₂ OCH ₃ , -CH ₂ OCH ₂ CH ₃ , -CH ₂ CH ₂ OCH ₃ , CH ₂ CH ₂ OCH ₂ CH ₃ , -CH ₂ 0 (C ₂ H ₄ 0) _m CH ₃ , -CH ₂ 0 (C ₃ H ₆ 0) _n CH ₃ and -CH ₂ 0 (C ₄ H ₈ 0) _P CH ₃ (m, n, p = 2 to 4) .

The variable R ⁷ preferably represents hydrogen, Ci to C ₄ alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, see. -Butyl and tert. -Butyl, phenyl, tolyl, C ₇ - to -C ₂ aralkyl such as benzyl and 2 -phenylethyl and Ci- to C ₄ -acyl such as formyl, acetyl, propionyl and butyryl.

The variable R ¹² is preferably hydrogen, Ci to C ₄ alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, see. -Butyl and tert-butyl, Ci to C ₄ alkoxy such as methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, see. -Butoxy and tert. -Butoxy, hydroxyl and Ci- to C ₄ -acyloxy such as acetoxy, propionyloxy and butyryl - oxy. R ^{12 is} particularly preferably hydrogen.

1,3- or 1,4-alkylene groups formed together by R ² and R ⁴ are especially -CH ₂ CH ₂ CH ₂ , -CH (CH ₃ ) CH ₂ CH ₂ -, -CH (CH ₃ ) CH ₂ CH (CH ₃ ) - _, -CH ₂ CH (CH ₃ ) CH ₂ -, -CH (C ₄ H ₉ ) CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -, -CH (CH ₃ ) CH ₂ CH ₂ CH ₂ - and -CH (C ₄ H9) CH ₂ CH ₂ CH ₂ -.

1,2- or 1,3-alkylene groups formed together by R ⁵ and R ⁷ are especially -CH ₂ CH ₂ -, -CH (CH ₃ ) CH ₂ -, -CH (CH ₃ ) CH (CH ₃ ) -, -CH (C ₂ H ₅ ) CH ₂ -, -CH (C ₄ H ₉ ) CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH (CH ₃ ) CH ₂ CH ₂ -, -CH (CH ₃ ) CH ₂ CH (CH ₃ ) -, -CH ₂ CH (CH ₃ ) CH ₂ - and -CH (C ₄ H ₉ ) CH ₂ CH ₂ -.

In a preferred embodiment, the copolymers contain as monomers B 5, 6-dihydro-4H-pyrans of the general formula Ia

(R ³ and R ⁶ = hydrogen, a and b = 1, c and d = 0) or

2.5 dihydrofurans of the general formula Ib

(R ¹ and R ² = hydrogen, a, b and d = 0, c = 1)

polymerized in, the variables designated by the formulas Ia and Ib having the meanings given above.

The following are examples of monomers B:

^{0 00 0}

⁰ OCH ₃ ° OCH ₃

The following are very particularly preferred as monomers B ^:

6-methoxy-5, 6-dihydro-4H-pyran OCH ₃ 2,5-dimethoxy-2,5-dihydrofuran

The preferably carboxyl group-free monomers of group C include, for example:

Ci to C ₃ o esters of acrylic acid or methacrylic acid, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, octadecyl (meth) acrylate and phenoxyethyl 1-acrylate;

Hydroxyalkyl esters of acrylic acid or methacrylic acid, e.g. Hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and butanediol-1,4-monoacrylate;

Alkyloxyalkyl esters of monoethylenically unsaturated

C ₃ - to Cicrmono- or -dicarboxylic acids, such as, for example, methyl diglycol acrylate and methyl pentaglycol methacrylate;

Diesters of maleic acid, e.g. Maleic acid dimethyl ester and maleic acid dibutyl ester;

linear and branched-chain α-olefins or mixtures thereof, such as e.g. Ethene, propene, butene, isobutene, pentene, cyclopentene, hexene, cyclohexene, octene, 2, 4, 4-trimethyl-1-pentene, optionally in a mixture with 2,4,4-trimethyl-2-pentene, 1- Octene,

Cβ-io-olefin, 1-dodecene, Cι ₂ " ₁ 4 -olefin, C ₂₀ - ₂₄ -olefin; metallocene-catalyzed oligo-olefins, such as oligopropene, oligohexene and oligo-octadecene; olefins with high α-olefin produced by cationic polymerization Proportion, such as reactive polyisobutene;

Acrylamides and alkyl substituted acrylamides such as e.g. Acrylamide, methacrylamide and N-tert. -Butyl acrylamide;

Vinyl and allyl alkyl ethers with 1 to 40 carbon atoms in the alkyl radical, where the alkyl radical can also carry further substituents such as a hydroxyl group, an amino or dialkylamino group or one or more alkoxylate groups, examples being: methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, 2- (diethylamino) ethyl vinyl ether, 2- (di-n-butylamino) ethyl - vinyl ether, methyl diglycol methyl ether and the corresponding allyl ether;

monomers containing sulfo groups, such as e.g. Allylsulfonic acid, methallylsulfonic acid, styrene sulfonate, vinyl sulfonic acid,

Allyloxybenzenesulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid;

Acrylamides or (meth) acrylates which have tertiary amino groups, e.g. 2- (N, N-Dimethylaπuno) ethyl (meth) acrylate, 2- (N, N-diethylammo) ethyl (meth) acrylate, 2 dimethylaminoethyl (meth) acrylamide and 3-dimethylammopropyl (meth) acrylamide, respectively their salts formed with mineral acids or their quaternization products with alkyl halides or alkyl sulfates;

Vinyl esters of ci- to C ₂ o-carboxylic acids, such as, for example, vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate and vinyl laurate;

N-vinyl carboxamides of carboxylic acids with 1 to 8 carbon atoms, such as e.g. N-Vmylformamide, N-Vinyl-N-methylformamide and N-Vmylacetamide;

further comonomers, e.g. Styrene, α-methylstyrene, butadiene, N-methylpyrrolidone, N-methylimidazole, acrolein, methacrolein, acrylonitrile, 4-methylpyridm, indene and diallyl-dimethylammonium chloride.

Preferred comonomers of the group C include methyl (meth) acrylate, ethyl (meth) acrylate, lauryl (meth) acrylate, butene, isobutene, 2,4,4 trimethyl-1-pentene, 1 octene, C _8-0 ₀ -olefin, 1 Dodecene, Cι ₂ -ι ₄ -01efin, C ₂₀ - ₂₄ -olefin, oligopropene, oligohexene, oligo-octadecene, reactive polyisobutene, methyl stearate, 2-acrylamido-2-methylpropane sulfonic acid, ethylhexyl methyl ether, styrene, acrolein and acrylonitrile.

The group A and C monomers are generally customary polymer building blocks and are readily accessible.

The group B monomers described by the general formula I can be obtained by various preparation methods. Examples include: Production from halogen / O-alkyl acetals with alcohols, production from aldehydes or ketones with hydroxy compounds, production from enol ethers with alcohols, production from enones and enol ethers according to a [4 + 2] cycloaddition or from ethers through electrolysis. These and other manufacturing methods are summarized in general form, for example in: Houoen-Weyl, Methods of Organic Chemistry, Vol. E14a / 1, ed. K. Hage¬mann, Thieme-Verlag 1991.

M.J. Han et al. describe in J. Pol. Sei., Part A, Polymer Chemistry, Vol. 28, 2719-2728 (1990) (3) copolymers of maleic anhydride with 5, 6 -dihydro-4H-pyran and various derivatives thereof, e.g. 6-methoxy-5, 6-dihydro-4H-pyran, 6-ethoxy-5, 6-dihydro-4H-pyran, 6-acetoxy-5, 6-dihydro-4H-pyran and 6-hydroxy-5, 6 - dihydro-4H-pyran. The copolymerization is carried out at a temperature of 70 ° C. in acetone using 2 -2'-AZODIS- (ISO-butyromtrile) as the initiator. The polymers are obtained in yields of between 20 and 72%. The copolymers were tested for their effectiveness against tumor cells.

The described copolymers of the present invention are preferably composed of 10 to 90 mol% of the monomers A and 10 to 90 mol% of the monomers B. Become

Monomers C co-polymerized in, their proportion is preferably 10 to 70 mol%.

The polymerization can be carried out in the presence or absence of inert solvents or inert diluents as bulk polymerization. It is advantageous when using solvents or diluents that both good dissipation of the heat of polymerization and low viscosity ensure smd. Such solvents can be used which are able to dissolve both the monomers and the resulting polymer. In this case it is a solution polymerization. The method of precipitation polymerization can also be used advantageously. Here, the monomers are at least partially soluble in the solvent, but not the resulting polymer. The product therefore fails in the course of the polymerization. This ensures a low viscosity during the polymerization and enables the solid product to be easily separated if necessary. Emulsion and suspension polymerization are further polymerization methods which can advantageously be used to prepare the copolymers described. Here, the monomers are present in dispersed form in a continuous phase. Water is usually used as the continuous phase, but hydrocarbons or other solvents can also be used. The advantage of these methods is that the polymerization can be carried out at low viscosities and the products, in particular when water is used as the continuous phase, can usually be used directly for their intended use.

In the case of precipitation, suspension or emulsion polymerization, the use of emulsifiers or protective colloids can be advantageous for stabilizing the droplets or particles. Examples of emulsifiers that can be used are: alkylphenol ethoxylates, primary alcohol ethoxylates, linear

Alkylbenzenesulfonates, alkyl sulfates, ethylene oxide / propylene oxide block copolymers or alkyl polyglucosides.

Protective colloids that can be used are, for example: cellulose derivatives, polyethylene glycol, polypropylene glycol, copolymers of ethylene glycol and propylene glycol, polyvinyl acetate, polyvinyl alcohol, polyvinyl ether, starches and starch derivatives, dextran, polyvinyl pyrrolidone, polyvinyl pyridine, polyethylene imine, polyvinyl imidomolezole, polyimide imidazole -methylsuccinimide, Polyvmyl -1, 3 -oxazoli - don-2, polyvinyl-2-methylimidazole and copolymers containing maleic acid or maleic anhydride. The emulsifiers or protective colloids are usually used in concentrations of 0.05 to 15% by weight, based on the monomers.

The method of precipitation or solution polymerization is preferably used to prepare the polymers described. Suitable solvents or diluents, for example toluene, o-xylene, p-xylene, ethylbenzene, technical mixtures of alkylaromatics, cyclohexane, technical aliphatic mixtures, acetone, cyclohexanone, tetrahydrofuran, dioxane, glycols and glycol derivatives, polyalkylene glycols and their derivatives , Diethyl ether, tert. -Butylmethyl ether, methyl acetate, ethanol, isopropanol and water or mixtures of different solvents, such as water / isopropanol or isopropanol / diethylene glycol. When water is used, there is a risk that some of the ethylenically unsaturated acetal used will saponify before it is polymerized. This can be prevented if the polymerization is carried out in a pH range which prevents saponification. This range can be found above pH 3. When using carboxyl- or sulfo group-containing monomers in aqueous solution, these are preferably used in partially neutralized form in order to ensure the correct pH range. It is also possible to work using a buffer system.

The polymerization can be carried out continuously or batchwise. The polymerization temperature can be selected in the range from 20 ° C. to 250 ° C., preferably in the temperature range from 50 ° C. to 160 ° C. The polymerization is preferably carried out in such a way that at least some of the monomers and the initiator are metered into the reaction vessel during the polymerization. The inflow time can be chosen arbitrarily, as a result of which the heat released during the polymerization is released over a defined period of time. The amount of monomers flowing into the reactor per unit of time can be kept constant; however, it is also possible to adjust the monomer flow or

To change the initiator flow during the polymerization. This makes it possible, for example, to achieve specific molecular weight distributions or modified copolymer composition compositions.

The copolymers described are generally prepared using free-radical initiators. Suitable radical initiators are preferably all those compounds which, at the polymerization temperature chosen in each case, have a half-life in the range from 1 minute to 10 hours. If the polymerization is first started at a lower temperature and ends at a higher temperature, it is expedient to work with at least two initiators which disintegrate at different temperatures, namely initially an initiator which disintegrates even at a lower temperature for starting the polymerization to use and then to complete the main polymerization with an initiator which decomposes at a higher temperature. As a rule, an initiator which is soluble in the particular solvent or diluent is used. In the case of polymerization in the dispersed phase, it is also possible to use initiators which are soluble only in the phase.

Peroxides or azo compounds are usually used as polymerization initiators, such as, for example, acetylcyclohexanesulfonyl peroxide, diacetyl peroxidicarbonate, dicyclohexyl peroxidicarbonate, di-2-ethylhexyl peroxydicarbonate, tert. -Butyl-perneodecanoate, 2,2'-azobis- (4-methoxy-2, 4-dimethylvalero-nitrile), 2, 2'-azobis- (2-methyl N-phenylpropionamide) dihydrochloride, tert. -Butyl perpivalate, dioctanoyl peroxide, dilauroyl peroxide, 2,2 'azobis (2,4-dimethylvaleromtnl), dibenzoyl- peroxide, tert. Butyl per-2-ethylhexanoate, tert. -Butylpermalemat, 2 2 '-azobis (isobutyronitrile), dimethyl 2-2' -azo bisisobutyrate, sodium persulfate, potassium persulfate, ammonium persulfate, bis (tert-butyl peroxide) cyclohexane, tert. Butyl peroxyisopropyl carbonate, tert. -Butylperacetat, Hydrogen peroxide, 2,2-Bιs (tert -butylperoxy) -butane, Dicumylperoxid, Di -tert. -amyl peroxide, di-tert. -butyl peroxide, Pmanhydroperoxid or tert. -Butyl hydroperoxide.

If, in addition to the initiators mentioned, salts or complexes of heavy metals, e.g. Copper, cobalt, manganese, iron, vanadium, cerium, nickel or chromium salts or organic compounds such as benzom, dimethylaniline or ascorbic acid, the half-value tents of the radical initiators indicated can be reduced. So you can, for example, tert. Activate butyl hydroperoxide with the addition of 5 ppm copper (II) acetylacetonate in such a way that polymerisation can take place at 100 ° C. The reducing component of redox catalysts can also be formed, for example, from compounds such as sodium sulfite, sodium bisulfite, sodium formaldehyde sulfoxylate and hydrazine.

Based on the monomers used in the polymerization, 0.01 to 20% by weight is preferably used

0.05 to 15% by weight of a polymerization initiator or a mixture of several polymerization initiators. 0.01 to 30% by weight of the reducing compounds are added as redox components. Heavy metals are used in the range of 0.1 to 100 ppm, preferably 0.5 to 10 ppm. It is often advantageous to use a combination of peroxide, reducing agent and heavy metal as the redox catalyst.

In order to produce polymers with a low average molecular weight, the polymerization is expediently carried out in m

In the presence of regulators. Suitable regulators are, for example, mercapto compounds, such as mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid, butyl mercaptan, n-dodecyl mercaptan or tert. Dodecyl mercaptan. Also suitable as controllers

Allyl alcohol, propionaldehyde, n-butyraldehyde and isobutyraldehyde, formic acid, ammonium formate, propionic acid, hydrazine sulfate, hydroxylammonium sulfate and butenols. If the polymerization is carried out in the presence of regulators, 0.05 to 20% by weight, based on the monomers used in the polymerization, are required. The Copolymers have a number average molecular weight of 500 to 1,000,000, preferably 800 to 150,000.

If the polymerization is carried out as bulk polymerization, the polymer must be converted into an aqueous solution or dispersion in order to obtain a usable product. For this purpose, one can, for example, after the end of the polymerization water to admit polymer and the mixture be solved ⁱ emer ge ^¬ suitable temperature or disperse. If necessary, the polymer can also be added as a melt or solid, with stirring, to a stirred tank charged with water.

When an organic Losungs- or precipitating agents used in the polymerization, as it must in order to arrive at a USAGE ^¬ dung capable product, be replaced ater largely removed and replaced with _W. In the case of a Fällungspolymeri ^¬ sation is possible to proceed in that the polymer is isolated by drying, filtration, or distilling off the solvent and then treated with this water. ^¬ often times it is advantageous to use a steam volatile solvent ^¬ medium to use for polymerization. This offers the possibility of removing the solvent by steam distillation. The method of steam distillation can also be used advantageously after a

Use solution polymerization in a steam-volatile ^solvent . The use of a defoamer or a foam damper can be advantageous here.

The cyclic and semicyclic acetals polymerized as monomers B can be saponified to the corresponding aldehydes in a polymer-analogous manner. May continue to einpolymeri ^¬ overbased ketals or Orthocarbonsäureester be converted into the corresponding ^¬ ketones or carboxylic acids. The presence of free or hydrated aldehyde groups, ketone groups or carboxyl groups in the polymers can increase both the water solubility of the products and their effectiveness. The formation of aldehyde, ketone or Orthocar- bonsauregruppen favor, heating the aqueous polymer solution or dispersion over a longer time ^¬ space. Extensive hydrolysis of the acetal groups enters into ^¬ particular, during steam distillation in an acidic medium. In order to accelerate the process of hydrolysis, a catalyst, such as p-toluenesulfonic acid, can also be added. In principle, with these Hydrolysis conditions also convert carboxylic anhydride structures from the monomers A into carboxyl groups.

The aldehyde-containing polymers obtained after the acetals have been opened can, if appropriate, also be converted in a polymer-analogous manner. For example, these can be converted to alcohols to give hemiacetals or acetals, to mercaptans to thioacetals, to ammonia or primary amines to Schiff bases, to hydroxylamines to oximes, to hydrazines to hydrazone, to secondary amines to enamines and with sodium bisulfite to bisulfite addition compounds put. Furthermore, the aldehyde groups can be reductively converted to alcohols or amines. Likewise, ketone or carboxyl groups obtainable by hydrolysis can be implemented in a polymer-analogous manner by methods known per se.

If a group A comonomer is a monoethylenically unsaturated dicarboxylic acid anhydride, such as e.g. Malemsaure¬ anhydride used, this anhydride group can be implemented in a polymer analog. The prerequisite for this is that the

Polymerization took place in the non-aqueous medium, so the anhydride group is not hydrolyzed. In order to partially esterify the anhydride groups contained in the copolymer, they are reacted with alcohols. The esterification is carried out with such amounts of alcohols that

10 to 70% of the total carboxyl groups resulting from the copolymerized dicarboxylic acid anhydride portions are esterified. This esterification is preferably carried out in the absence of water. Suitable alcohols can contain 1 to 40, preferably 3 to 30, carbon atoms. Primary, secondary and tertiary alcohols can be used.

Both saturated aliphatic alcohols and unsaturated alcohols, such as oleyl alcohol, can be used here. Monohydric, primary or secondary alcohols are preferably used, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol and isomers, n-hexanol and isomers, n-octanol and isomers, such as, for example, 2-ethylhexanol ; Nonanols, decanols, dodecanols, tridecanols, cyclohexanol, tallow fatty alcohol, stearyl alcohol, alkoxylated Ci to C ₃₀ alcohols, such as, for example, methyl diglycol and methyl pentaglycol, or polyalkylene glycols, such as, for example, polyethyleneglycol, polypropylene glycol and polytetrahydrofuran, as well as the technically available throughdioxydosulfane, as well as the technically available throughdioxydosulfane or alcohol mixtures with 9 to 19 carbon atoms, such as C _g / n-oxo alcohol, C ₃ / i ₅ -oxo alcohol, and Ziegler alcohols with 12 to 24 carbon atoms. Alcohols are preferably used with 3 to 30 C-atoms, such as n-butanol, isobutanol, Amyl¬ alcohol, 2-ethylhexanol, tridecanol, tallow fatty alcohol, stearyl alcohol, _C9 / u-oxo, C _{_13/15} -oxo alcohol, Cι ₂ / ι ₄ -Al - fole ^® and Cι ₆ / ιe-Alfoie. The esterification can optionally be accelerated by a catalyst such as p-toluenesulfonic acid.

The copolymers containing anhydride groups can also be amidated or imidized by adding primary or secondary amines. The amidation / imidization is carried out with amounts of amines such that 10 to 70% of the total carboxyl groups resulting from the copolymerized dicarboxylic acid anhydride units are amidated or 10 to 70% of the polymerized dicarboxylic acid anhydride units are imidized.

Ammonia and primary and secondary nurse can be used to form the amide. The amide formation is preferably carried out in the absence of water by reaction of the anhydride groups of the copolymer with ammonia or the amines. The primary and secondary amines in question can have 1 to 40, preferably 3 to 30, carbon atoms. Suitable amines are, for example, methylamine, ethylamine, n-propylamine, isopropylamine, n-butylamine, isobutylamine, hexylamine, cyclohexylamine, methylcyclohexylamine, 2-ethylhexylamm, n-octylamine, isotridecylamm, tallow fatty amine, stearylamm, oleylamine, dimethylamm, diethyl n-propylamine, di-isopropylamine, di-n-butylamm, di-isobutylamine, dihexylamine, di-cyclohexylamine, di-methylcyclohexylamine, di-2-ethylhexylamine, di-n-octylamine, di-isotridecylamm, di- Tallow fat amine, di-stearylamm, di-oleylamine, ethanolamm, di-ethanol amine, n-propanolamine, di-n-propanolamine, sarcosine, taurine and morpholine. By choosing suitable reaction conditions, imide structures can be produced with ammonia or primary amines from the dicarboxylic acid anhydride units of the copolymer.

After the partial conversion of the anhydride groups into half-ester, half-amide or imide groups and possibly subsequent hydrolytic opening of the acetal, ketal or orthoester groups, the remaining anhydride groups of the polymer can be hydrolysed. The hydrolysis of further of the anhydride groups still present in the copolymer can also be carried out simultaneously with the partial neutralization still required, by adding an aqueous base to the partially esterified, amidated or imidized copolymer which still contains anhydride groups. to A suitable catalyst, such as 4-dimethylaminopyridine, can optionally also be added to accelerate the hydrolysis of the anhydride groups.

The copolymers containing carboxyl groups are generally converted into a neutralized form. 10 to 95% of the carboxyl groups are preferably neutralized. As a base, e.g. Alkali or alkaline earth metal hydroxides, e.g. Sodium hydroxide, potassium hydroxide or magnesium hydroxide, alkali or alkaline earth metal carbonates, such as e.g. Sodium carbonate or potassium carbonate, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethanolamine, diethanolamine, dimethylethanolamine, triethanolamine or morpholine can be used. The neutralization can either already take place during the polymerization, for example by using partially neutralized monomers, or can be carried out after the polymerization and, if appropriate, after the hydrolytic opening of the acetal, ketal or orthocarboxylic acid ester structures.

The copolymer solutions or dispersions obtainable in this way can be used excellently as tanning agents in leather and fur production. For example, the copolymers used according to the invention can be used for the sole tanning or pre-tanning of pelts and pelts in aqueous liquors. In the case of single tanning and pre-tanning of pelts and pelts, the procedure is expediently such that the speckled pelts, for example cowhide pelts with a gap thickness of 1.5 to 4 mm, or pelts, for example sheepskin pelts, at a pH of 2 to 7, in particular 2.5 to 4.5 and a temperature of 15 to 40 ° C., in particular 20 to 35 ° C., are treated with an aqueous solution or dispersion of the copolymers used according to the invention for a period of 2 to 20 hours the. The treatment takes place, for example, by drumming in the barrel. The required amounts of copolymers used according to the invention are normally 2 to 30% by weight, in particular 5 to 25% by weight, based on the pelt weight. The fleet length, i.e. the percentage weight ratio of the treatment liquor to the goods is usually

30 to 200% for the bare and 100 to 2000% for the bare, each based on the bare weight.

After the treatment, the leather or fur is usually adjusted to a pH of 2 to 8, in particular 3 to 5, for which purpose, for example, magnesium oxide, sodium carbonate, sodium hydrogen carbonate or an organic acid such as formic acid or its salts, optionally treated with other tanning agents and, if desired, colored and greased towards the end or after the end of the tanning process.

Furthermore, the copolymers used according to the invention can be used for tanning pelts and pale skin together with the tanning agents of the main tanning, which can be, for example, chrome, aluminum, titanium or zircon tanning. In this case, the working conditions with regard to pH, temperature and duration of the treatment are adjusted to the requirements of the main components of the tanning, the same applies to the treatment apparatus and the liquor length as well as to the aftertreatment. The amount of copolymer used according to the invention is normally 0.1 to 20% by weight, in particular 0.5 to 14% by weight, based on the pale weight.

Furthermore, the copolymers used according to the invention can be used for retanning leather and fur which have already been tanned, for example chrome leather ("wet blue"), "wet white" (with, for example, aldehydes or pelts or pelts pretanned with synthetic tanning agents) or vegetable tanned leather or fur, be used in aqueous liquor. Chrome leather is preferably retanned. In this case, the procedure is generally such that the pickled pelts and skins, for example round pelts with gap thicknesses of 1.5 to 4 mm, with, for example, a chromium-containing tannin such as a chromium III salt, e.g. Cr (III) sulfate, tanned in a manner known per se, the pre-tanned skin thus obtained is deacidified and at a pH of 2 to 7, in particular 2.5 to 6, and at temperatures of 15 to 60 ° C., in particular at 25 to 45 ° C. for a period of 0.25 to 12 hours are treated with an aqueous solution or dispersion of the copolymers used according to the invention. This treatment takes place, for example, by drumming in a barrel. The amount of copolymers used according to the invention is normally 2 to 30% by weight, in particular 5 to 25%, based on the shaved weight of the leather. The liquor length is usually 30 to 200% for bare and

100 to 2000% for pelts, each based on the fold weight of the leather.

After and if necessary also before the treatment, the leather or fur is usually adjusted to a pH of 3 to 5, for which purpose magnesium oxide or an organic acid such as formic acid or its salts is used, for example. and colors and greases towards the end or after treatment if desired.

The thus retanned leather or skin tanning can before the disadvantages with the inventively used copolymers additionally _ä suddenly with other tanning agents as other Polymergerb _S toffen, synthetic or vegetable tanning agents be ^¬ concerns have been. The inventively USAGE ^¬ Deten copolymers can be used simultaneously with such additional tanning agents.

As additionally or simultaneous tanning all _above usual means having a tanning effect on Bare Bare and coat into consideration. Eme comprehensive treatment of such tanning agents found, for example m Ullmann Enzyklopä ^¬ of Industrial Chemistry, 3rd Edition, 11.Band, S.585 to 612 (1960). Tannin classes to be mentioned individually are the mineral tannins, for example chromium, aluminum, titanium and zirconium salts, the synthetic tannins, the vegetable tannins and the polymer tannins.

D _i e leather produced with the inventively used copolymers provide excellent results posted L _i chtechtheit and Warmestabilitat. This is particularly noticeable on chrome-pretanned leather. In addition, the copolymers used according to the invention have very good fullness, high softness and good solid grain even when used in quantities. With large quantities, the leather does not get stuck.

Surprisingly _Ü is no longer ben disadvantage of polymers based on acrylic and methacrylic acid-base in farbeπschen behavior in the inventively used copolymers gege ^¬. Thus, such products provide leather with very dark-emer cycles F _ä coloring and can be achieved with an improved Durchfarbung wherein gle _i chzeitig very gleichmaßige and level dyeings.

Em particular advantage of the inventively copolymers used is the fact that they can, in contrast to herk _ö mmlichen syntans no health hazard Denden unsulfo- _i Erten phenols n as residual monomers contained and Ver ^¬ gle _i ch to herk _ö mmlichen polymer tanning by the increased React _i v _i t t _ä the aldehyde functions latently present in the copolymer t _i ons a better exhaustion of the tanning liquors ore ⁱ elen and so that a lower pollution of the wastewater with organic substances is observed.

Since some of the copolymers described are new, the present invention also relates to copolymers of

in which the variables have the following meaning

R ^L , R ^{2 are} independently hydrogen,

Ci to Cio alkyl, Ci to Cirj alkoxy, Ammo, Ci to C ₄ alkylamino, or

Di-Ci to C ₄ alkylamino,

R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ , R ^{1: L} independently of one another hydrogen, Ci to Cio alkoxy, Ammo, Ci to C ₄ alkylammo, di Ci to C ₄ alkyl ammo, C ₆ to C ₄ aryl, C ₇ to Ciβ aralkyl, carboxyl, Ci to C ₂ rj alkoxycarbonyl, C interrupted by one to five non-adjacent oxygen atoms ₂ - to Ciβ-alkyl or sulfo or phosphono groups,

R ^{7 is} hydrogen, C _x - to Cι ₀ alkyl,

C _ß - to Cι ₄ aryl, C ₇ - to Ci ₈ "aralkyl or Ci- to Cio-acyl,

Ri ^{2 is} hydrogen, C _x - to Cι ₀ alkyl,

Ci to Cio alkoxy, hydroxyl or Ci to Cio acyloxy and

a, b, c, d independently of one another the number 0 or 1, where R ² and R ⁴ together also represent a 1,3- or 1,4-alkylene group with 3 to 12 carbon atoms and

C) 0 to 70 mol% of further copolymerizable monomers

with the exception of those, as monomer A maleic anhydride and as monomer B 6-acetoxy-5, 6-dihydro-4H-pyran,

Contain 6-methoxy-5, 6-dihydro-4H-pyran, 6-ethoxy-5, 6-dihydro-4H-pyran or 6-hydroxy-5, 6-dihydro-4H-pyran in copolymerized form,

and hydrolysis products and polymer-analogous reaction products of these copolymers.

The disclaimed copolymers of maleic anhydride and the four monomers B mentioned above are already known from (3), but are recommended there for an entirely different use.

Examples

Unless otherwise stated, the percentages relate to the weight.

The K values of the copolymers were determined according to H. Fikentscher, Cellulose-Chemie, Vol. 13, 58-64 and 71-74 (1932) in aqueous solution on the sodium salts of the copolymers at a concentration of 1% by weight, a pH Value of 7 and a temperature of 25 ° C determined.

The solids contents were determined by drying at 2 hours / 80 ° C. in vacuo.

Preparation of the copolymers

example 1

147.0 g of maleic anhydride and 1178 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater and heated to 110 ° C. under inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5,6-dihydro-4H-pyran, was metered in uniformly into this solution over 3 hours. Starting with inflow 1, 4 hours were the inlet 2, consisting of 22.6 g tert. -Butyl-per-2-ethyl hexanoate and 94 g of toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, a light brown, low-viscosity suspension was obtained. 200 g of demineralized water were added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. When the steam distillation had ended, a brown solution was present. The solution was cooled and neutralized with 154.0 g sodium hydroxide solution (50%). A dark brown, clear solution with pH 7.2 and a solids content of 33.4% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 15.0.

Example 2

147.0 g of maleic anhydride and 1178 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated to 110 ° C. under inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly into this solution over 3 hours. Starting with feed 1, feed 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl- per-2-ethylhexanoate and 94 g toluene, metered in evenly. The reaction mixture was then post-polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, a light brown, low-viscosity suspension was obtained. 200 g of demineralized water were added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. After the steam distillation had ended, a brown solution was present. 0.32 g of p-toluenesulfonic acid was added to the solution and the mixture was stirred at 100 ° C. for 1 hour. The solution was then cooled and neutralized with 154.0 g of sodium hydroxide solution (50%). A black-brown, clear solution with pH 7.2 and a solids content of 33.6% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 15.0.

Example 3

147.0 g of maleic anhydride and 1178 g of o-xylene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated to 145 ° C. under inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was uniformly added to this solution over 3 hours added. Starting with feed 1, feed 2 consisting of 22.3 g of tert was added over 4 hours. -Butyl- per-2-ethylhexanoate and 94 g o-xylene, evenly added. The reaction mixture was then polymerized at 145 ° C. for a further 2 hours. After the end of the polymerization, a brown, low-viscosity suspension was obtained. 200 g of demineralized water were added to the reaction mixture and the solvent o-xylene was distilled off azeotropically by introducing steam. When the steam distillation had ended, a brown solution was present. The solution was cooled and neutralized with 120.0 g of sodium hydroxide solution (50%). A dark brown, clear solution with pH 7.1 and a solids content of 41.0% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 12.2.

Example 4

200.0 g of 6-methoxy-5, 6-dihydro-4H-pyran and 1350 g of toluene were placed in a stirred 4 -1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater, and 1350 g of toluene were added to 110 under inert gas ° C heated. Feed 1, consisting of 200.0 g of methacrylic acid, was metered in uniformly into this solution over 2 hours. Starting with feed 1, feed 2 consisting of 4.0 g of 2,2'-azoisobutyronitrile and

250 g of toluene are metered in uniformly. The reaction mixture was then polymerized at 110 ° C. for a further 1.5 hours. The suspended solid product was filtered off and washed with toluene. The slightly yellowish powdery product was dried in vacuo. 234 g of the copolymer were isolated.

For transfer into an aqueous solution, 90.0 g of the copolymer with 360 g of fully demineralized water were placed in a 2-1 glass reactor provided with a water vapor inlet tube and Liebig cooler and slowly heated to 100.degree. Water vapor was passed through the mixture during 4 hours. A slightly brownish, cloudy solution with pH 3.0 and a solids content of 9.3% was obtained. The K value of a 1% strength aqueous solution adjusted to pH 7 using sodium hydroxide solution was 46.9.

Example 5

In a stirred 2-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater, 40.0 g of 6-methoxy-5, 6-dihydro-4H-pyran and 600 g of xylene are introduced and heated to 90 ° C. under inert gas. Feed 2, consisting of 160.0 g of methacrylic acid and 100 g of o-xylene, was metered in uniformly into this solution over the course of 2 hours. Simultaneously with feed 1, feed 2 consisting of 4.0 g of tert was added over 3 hours. -Butyl- per 2-ethylhexanoate and 100 g o-xylene, evenly added. The reaction mixture was then polymerized at 90 ° C. for a further 1.5 hours. After the solvent had been separated off in a rotary evaporator, 205.0 g of the copolymer were obtained in the form of a fine white powder.

For transfer into an aqueous solution, 175.0 g of the copolymer and 525 g of fully demineralized water were placed in a 2-1 glass reactor with a Liebig cooler and slowly heated to 100.degree. Nitrogen was passed through the mixture for 30 mm and residues of o xylene were distilled off. The mixture was cooled to 50 ° C. and neutralized by slowly adding 120.0 g of sodium hydroxide solution (50%). A yellow, cloudy solution with pH 7.15 and a solids content of 25.0% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 61.4.

Example 6

26.1 g of 6-methoxy-5, 6 dihydro-4H-pyran and 600 g of xylene were placed in a stirred 2-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and at 90 ° under inert gas C heated. Feed 2, consisting of 173.9 g of methacrylic acid and 100 g of o-xylene, was metered in uniformly into this solution over the course of 2 hours. Simultaneously with feed 1, feed 2 consisting of 4.0 g of tert was added over 3 hours. -Butyl- per-2-ethylhexanoate and 100 g o-xylene, evenly metered. The reaction mixture was then polymerized at 90 ° C. for a further 1.5 hours. After the solvent had been separated off in a rotary evaporator, 217.0 g of the copolymer were obtained in the form of a fine white powder.

195.0 g of the copolymer and 550 g of fully demineralized water were converted into one in order to transfer my aqueous solution

2-1 glass reactor with Liebig cooler and slowly heated to 100 ° C. Nitrogen was passed through the mixture for 40 mm and residues of o-xylene were distilled off. The mixture was diluted with 200 g of deionized water, cooled to 50 ° C. and neutralized by slowly adding 135.0 g of sodium hydroxide solution (50%). A yellow, cloudy solution with a pH of 7.15 and a solids content of 24.4% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 66.3.

Example 7

40.0 g of 6-methoxy-5, 6-dihydro 4H-pyran and 600 g of o-xylene were placed in a stirred 2-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater and placed under inert gas Heated to 110 ° C. Feed 2, consisting of 160.0 g of methacrylic acid and 100 g of o-xylene, was metered in uniformly into this solution over the course of 2 hours. Simultaneously with feed 1, feed 2 consisting of 4.0 g of tert was added over 3 hours. -Butyl- per-2-ethylhexanoate and 100 g o-xylene, evenly metered in. The reaction mixture was then polymerized at 110 ° C. for a further 1.5 hours. After the solvent had been separated off in a rotary evaporator, 206.0 g of the copolymer were obtained in the form of a fine white powder.

For transfer to an aqueous solution, 170.0 g of the copolymer and 510 g of fully demineralized water were placed in a 2-1 glass reactor with a Liebig cooler and slowly heated to 100.degree. Nitrogen was passed through the mixture for 45 mm and residues of o-xylene were distilled off. The mixture was cooled to 50 ° C. and neutralized by slowly adding 115.0 g of sodium hydroxide solution (50%). A yellow, cloudy solution with pH 7.15 and a solids content of 27.2% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 46.4.

Example 8

147.0 g of maleic anhydride and 1178 g of toluene were placed in a stirred 4 liter glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated under reflux under inert gas. To this solution, feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly over 3 hours. Simultaneously with feed 1, feed 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl- per-2-ethylhexanoate and 94 g toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, he kept a light brown, low-viscosity suspension. At an internal temperature of 100 ° C to the reaction mixture 318 g of deionized water and 38 g sodium hydroxide solution (50%) were added to give ^¬. Then, by introducing water vapor Solvent toluene distilled off azeotropically. The solution was cooled and neutralized with 117.0 g sodium hydroxide solution (50%). A dark brown, slightly cloudy solution with pH 7.1 and a solids content of 34.3% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 14.1.

Example 9

147.3 g of maleic anhydride and 1179 g of toluene were placed in a stirred 2 -1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater and heated to reflux under inert gas. Feed 1, consisting of a mixture of 137.1 g of 6-methoxy-5, 6-dihydro-4H-pyran and 33.7 g of 1-octene, was metered in uniformly into this solution over 3 hours. Starting with feed 1, feed 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl-per-2-ethylhexanoate and 94 g toluene, metered in evenly. The reaction mixture was then polymerized for a further 2 hours at 110 ° C. After the end of the polymerization, a yellow, low-viscosity suspension was obtained. At an internal temperature of 100 ° C., 318 g of demineralized water were added to the reaction mixture. The solvent toluene was then distilled off azeotropically by introducing steam. The solution was cooled and neutralized with 155.0 g sodium hydroxide solution (50%). A red-brown, clear solution with pH 7.1 and a solids content of 39.1% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 13.8.

Example 10

152.5 g of maleic anhydride and 1179 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 3 automatic feed metering devices, reflux condenser and oil bath heater and heated under reflux under inert gas. To this solution, feed 1, consisting of 129.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly over 3 hours. Starting with feed 1, feed 2, consisting of 36.5 g of methacrylic acid, was metered in uniformly over 3 hours. Also starting at the same time as feed 1, feed 3, consisting of 22.6 g of tert, was added over 4 hours. -Butyl- per-2-ethylhexanoate and 94 g toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, a yellow, low-viscosity suspension was obtained. At a

Internal temperature of 100 ° C., 318 g of demineralized water were added to the reaction mixture. Then by conduct water vapor the solvent toluene distilled off azeotropically. The solution was cooled and neutralized with 182.0 g sodium hydroxide solution (50%). A red-brown, clear solution with pH 7.1 and a solids content of 40.3% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 20.2.

Example 11

147.0 g of maleic anhydride and 1178 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater and heated to 95 ° C. under inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly into this solution over 5 hours. Starting with feed 1, feed 2, consisting of 22.6 g, was tert during 6 hours. Butyl per-2-ethyl hexanoate and 94 g of toluene, metered in uniformly. The reaction mixture was then polymerized at 95 ° C. for a further 2 hours. After the end of the polymerization, a yellow, low-viscosity suspension was obtained. At an internal temperature of 85 ° C., 318 g of completely deionized water were added to the reaction mixture. The toluene solvent was then azeotropically distilled off by introducing steam. The solution was cooled and neutralized with 155.0 g of sodium hydroxide solution (50%). A red-brown, clear solution with pH 7.1 and a solids content of 34.3% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 14.5.

Example 12

139.9 g of maleic anhydride and 1179 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated under reflux under inert gas. To this solution, feed 1, consisting of a mixture of 130.2 g of 6-methoxy-5, 6-dihydro-4H-pyran and 48.0 g of 1-dodecene, was metered in uniformly over 3 hours. Starting with feed 1, feed 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl-per-2-ethylhexanoate and 94 g toluene, metered in evenly. The reaction mixture was then polymerized for a further 2 hours at 110 ° C. After the end of the polymerization, a two-phase mixture consisting of an upper yellow, clear phase and a lower brown phase was obtained. At an internal temperature of 90 ° C, 318 g of demineralized water were added to the reaction mixture given. The toluene solvent was then distilled off azeotropically by introducing steam. The solution was cooled and neutralized with 148.0 g sodium hydroxide solution (50%). A red-brown, clear solution with pH 7.1 and a solids content of 33.1% was obtained. The K value of 1% aqueous solution of the copolymer (pH 7) was 14.4.

Example 13

27.2 g of maleic anhydride and 1179 g of cyclohexane were placed in a stirred 4-1 glass reactor with anchor stirrer, 3 automatic feed metering devices, reflux condenser and oil bath heating and heated to 70 ° C. under inert gas. To this mixture, feed 1, consisting of 240.8 g of 6-methoxy-5, 6-dihydro-4H-pyran and feed 2, consisting of 48.0 g of 1 dodecene, was metered in uniformly over 3 hours. In the same way as feed 1 and 2, feed 3 consisting of 3.2 g of tert was added over 4 hours. -Amylperpivalat and 94 g cyclohexane, metered in evenly. The reaction mixture was then polymerized for a further 2 hours at 70.degree. After the end of the polymerization, the solvent was distilled off and then 318 g of demineralized water were added to the reaction mixture and the batch was heated to 100.degree. The solution was cooled and adjusted to pH 7 with sodium hydroxide solution. A brown solution with a solids content of 42.1% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 36.

Example 14

25.2 g of maleic anhydride and 341 g of tetrahydrofuran were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated under reflux under inert gas. Feed 1, consisting of 294.7 g of 2,5-dimethoxy-2,5-dihydrofuran, was metered in uniformly into this solution over 3 hours. Starting with feed 1, feed 2, consisting of 6.4 g of 2,2-azo-bis (2,4-dimethylvalerontrium) and 50 g of tetrahydrofuran, was metered in uniformly over 4 hours. The reaction mixture was then polymerized for a further 2 hours at 67.degree. After the end of the polymerization, the solvent was distilled off and 318 g of demineralized water were added to the reaction mixture. The mixture was then heated to 100 ° C. and adjusted to pH 7 with sodium hydroxide solution. A yellow-brown solution with a solids content of 43.1% was obtained. The K value of a 1% aqueous solution of the copolymer (pH 7) was 18.3.

Example 15

138.0 g of maleic anhydride and 1179 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater and heated under reflux under inert gas. Feed 1, consisting of 182.0 g of 2,5-dimethoxy-2,5-dihydrofuran, was metered in uniformly into this solution over 3 hours. Starting with feed 1, feed 2 consisting of 12.8 g was tert during 4 hours. -Butyl-per-2-ethyl-hexanoate and 94 g of toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, the internal temperature was lowered to 90 ° C. and 320 g of demineralized water were added to the reaction mixture. The toluene solvent was then distilled off azeotropically by introducing steam. The solution was cooled and adjusted to pH 7 with sodium hydroxide solution. A red-brown solution with a solids content of 40.8% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 25.5.

Example 16

In a stirred 4 1 glass reactor with anchor stirrer, 2 automatic feed metering devices. The reflux condenser and oil bath heater were placed in 144.9 g of maleic anhydride and 231 g of butanediol monomethyl ether and heated to 90 ° C. under an inert gas. Feed 1, consisting of a mixture of 113.6 g of 6-methoxy-5, 6-di-hydro-4H-pyran and 61.5 g of styrene, was metered in uniformly into this mixture over 3 hours. Starting with feed 1, feed 2 consisting of 9.6 g of tert was added over 4 hours. -Butyl-per-2-ethylhexanoate, evenly added. The reaction mixture was then polymerized at 90 ° C. for a further 2 hours. After the end of the polymerization, the internal temperature was raised to 160 ° C. over 45 minutes and the water formed was distilled off. An aqueous, neutral solution with a solids content of 36.1% was then prepared by adding demineralized water and sodium hydroxide solution. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 29.2. Example 17

134.1 g of 6-methoxy-5, 6-dihydro-4H-pyran, 650 g of fully demineralized water and 3.2 g were placed in a stirred 4 -1 glass reactor with anchor stirrer, 3 automatic feed metering devices, reflux condenser and oil bath heater Natπumdihydrogenphosphat submitted and heated under inert gas to 80 ° C internal temperature. To this solution, feed 1, consisting of 141.2 g of acrylic acid sodium salt, and feed 2, consisting of 90 g of a 50% aqueous solution of acrylamide, were metered in uniformly over 3 hours. Starting with feeds 1 and 2, feed 3, consisting of a solution of 3.2 g of 2,2'-azobis-2-methylpropionamidine dihydrochloride in 50 g of deionized water, was metered in uniformly over 4 hours. The reaction mixture was then polymerized at 80 ° C. for a further 2 hours. After the end of the polymerization, the internal temperature was lowered and the reaction mixture was adjusted to pH 7 with dilute sodium hydroxide solution. A clear solution with a solids content of 25.8% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 70.8.

Example 18

133.8 g of maleic anhydride and 1179 g of toluene were placed in a stirred 4 -1 glass reactor with anchor stirrer, 3 automatic feed metering devices, reflux condenser and oil bath heater and heated to reflux under inert gas. To this solution, feed 1, consisting of 93.4 g of 6-methoxy-5,6-dihydro-4H-pyran, and feed 2, consisting of 92.8 g of dimethylaminopropyl methacrylamide, were metered in uniformly over 3 hours. Beginning with feed 1, feed 3 consisting of 22.6 g was tert during 4 hours. -Butyl -per-2-ethyl¬ hexanoate and 94 g of toluene, metered in uniformly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, the internal temperature was lowered to 90 ° C. and 320 g of completely demineralized water were added to the reaction mixture. The toluene solvent was then distilled off azeotropically by introducing steam. The solution was cooled and adjusted to pH 7.1 with sodium hydroxide solution. A red-brown solution with a solids content of 40.8% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 31.5. Example 19

147.0 g of maleic anhydride and 1178 g of toluene were placed in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating and heated to 111 ° C. under inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly into this solution over 3 hours. Simultaneously with feed 1, feed 2 consisting of 22.6 g was tert during 4 hours. Butyl per-2-ethyl hexanoate and 94 g of toluene, metered in uniformly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. 209.0 g of Tπdecylamm were added to the resulting light brown, low-viscosity suspension and the reaction mixture was heated to 160 ° C. over 45 minutes. 200 g of fully demineralized water were then added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. When the steam distillation had ended, a brown dispersion was present. The dispersion was cooled and adjusted to pH 7 with dilute sodium hydroxide solution. A brown dispersion with a solids content of 26.3% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 19.9,

Example 20

147.0 g of maleic anhydride, 400 g of toluene and 3.2 g of a copolymer of maleic anhydride and dusobutene, the anhydride groups of which were 60%, were in a stirred 4 -1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating n decanol had been esterified, initially charged and heated to 111 ° C. under an inert gas. Feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly into this solution over 3 hours. Simultaneously with feed 1, feed 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl- per-2-ethylhexanoate and 80 g toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, he kept a light brown, low-viscosity suspension. 200 g of completely demineralized water were added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. After the steam distillation had ended, a brown solution was present. The solution was cooled and neutralized with 158.0 g sodium hydroxide solution (50% ⁾ . It became a dark brown, clear solution pH 7.3 and a solids content of 34.4%. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 16.2.

Example 21

147.0 g of maleic anhydride, 400 g of toluene and 3.2 g of polyoctadecyl methyl ether were placed in a stirred 4 l glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heating, and the mixture was heated to 110 ° C. under inert gas. To this solution, feed 1, consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran, was metered in uniformly over 3 hours. Starting with feed 1, feed 2, consisting of 22.6 g of tert-butyl per-2-ethylhexanoate and 80 g of toluene, was metered in uniformly over 4 hours. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, a light brown, low-viscosity suspension was obtained. 200 g of demineralized water were added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. After the steam distillation had ended, a slightly cloudy, brown solution was present. The solution was cooled and neutralized with 158.0 g sodium hydroxide solution (50%). A dark brown, clear solution with pH 7.1 and a solids content of 32.7% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 13.9.

Example 22

147.0 g of maleic anhydride, 400 g of toluene and 3.2 g of a copolymer of maleic anhydride and styrene with a number average molecular weight of were in a stirred 4-1 glass reactor with anchor stirrer, 2 automatic feed metering devices, reflux condenser and oil bath heater

110,000, submitted and heated to 111 ° C under inert gas. Feed 3 consisting of 171.0 g of 6-methoxy-5, 6-dihydro-4H-pyran and 16.0 g of n-dodecyl mercaptan was metered in uniformly into this solution over 3 hours. At the same time as inlet 1, inlet 2 consisting of 22.6 g of tert was added over 4 hours. -Butyl-per-2-ethylhexanoate and 80 g toluene, metered in evenly. The reaction mixture was then polymerized at 110 ° C. for a further 2 hours. After the end of the polymerization, a light brown, low-viscosity suspension is obtained. 200 g of demineralized water were added to the reaction mixture and the organic solvent was distilled off azeotropically by introducing steam. After finishing After steam distillation there was a brown solution. The solution was cooled and neutralized with 155.0 g sodium hydroxide solution (50%). A dark brown, clear solution with pH 7.1 and a solids content of 36.6% was obtained. The K value of a 1% strength aqueous solution of the copolymer (pH 7) was 11.2.

Application in leather production

Example 23 (single use)

Pickled bare bones with a gap thickness of 3 mm were mixed in 50% water and 50% pickle liquor at 20 ° C. and a pH of 3.0 with 4% based on solids content, a copolymer prepared according to Example 2. The walk time was 180 minutes. The liquor was then heated to 40.degree. C., mixed with 0.8% commercially available magnesium oxide and left at this temperature for 180 minutes with milling. The mixture was then cooled to room temperature and agitated overnight in a barrel. The pH was then 4.0. The mixture was heated to 40 ° C. and adjusted in portions over a period of 5 hours to pH 6.8 using sodium bicarbonate. The leather was rinsed with water and stored on trestle overnight. The shrink temperature was 81 ° C. In contrast, the shrinking temperature of untreated nakedness was only 68 ° C.

Example 24 (retanning from chrome leather to furniture leather)

A cowhide blue with a fold thickness of 1.2 mm was first washed with 300% water at 30 ° C and then in 100%

Deacidify the liquor at 30 ° C with sodium formate and sodium bicarbonate to a pH of approx. 5.0. After a brief rinse, the leather in 100% float with 3%, based on the solid was ^¬ product, the polymer prepared in Example 1 retanned at 40 ° C in the barrel. After 90 minutes of drumming, the leather was rinsed again and dyed in 100% liquor at 50 ° C. with 1% of a commercially available metal complex leather dye, greased with 8% of a commercially available fat liquor and adjusted to a pH of 4.0 with formic acid. The leather was stored on trestle overnight, then stretched wet and dried. After shavings, tunnels and millen, a soft, very full leather with a deep, even color and good through-coloring in the cut was obtained. The mill grain showed a fine, even image, even in the flames and flanks. Examples 25 and 26

Analogously to Example 24, 3%, based on the solids content of the products, of the copolymers from Examples 3 and 4 were used for retanning chrome bovine leather into furniture leather. In both cases, very full and soft leathers were obtained, which were particularly impressive due to their good depth of color with good color throughout and a uniform mill grain.

Comparative example A (retanning from chrome leather to furniture leather)

A commercially available polymer based on methacrylic acid was used in the same way as in Example 24 for retanning chrome cowhide

Furniture leather used. The leather thus obtained showed less fullness and, with the same amount of dye, a lighter color both on the surface and in the cut.

Example 27 (retanning from chrome leather to upper leather with a high amount of polymer used)

A 1.5 mm thick beef wet blue was rinsed in the usual manner, washed and then deacidified in 100% liquor with sodium formate at 30 ° C. to a pH of 4.5. After washing, it was drummed in 100% liquor with 5%, based on the solids content, of the copolymer from Example 1, 90 mm at a temperature of 40 ° C. The leather was then washed again and dyed in 100% liquor at 50 ° C. with 1% of a commercially available leather dye within 20 minutes. This was followed by greasing in the same liquor with 4% of a commercially available fat liquor. The pH was then adjusted to 3.6 with formic acid. After a short rinse, the leather was stretched out, dried, machined, and stolled. Leather was obtained with good fullness and firm grain, a round, supple handle and a very level, deep color.

Examples 28 to 48 (retanning from chrome leather to shoe upper leather with a high amount of polymer used)

Analogously to Example 27, 5%, based on the solids content, of the copolymers from Examples 2 to 22 were used as retanning agents. In all cases, very full and deep-colored leather was obtained, which varied in softness depending on the comonomer. Commercially available polymers based on acrylic acid compared to the same procedure The above examples are too hard, rough leather with an uncomfortable grip.

Example 49 (retanning from chrome leather to upper leather with a low amount of polymer tanning agent)

A 1.8 mm thick fold was rinsed in the usual way, washed and then deacidified in 100% liquor with sodium formate to a pH of 4.4. After a new wash, drumming in 100% liquor at 30 ° C. was first carried out for 30 minutes with 1.0% of a commercial dispersant (phenolsulfonic acid-formaldehyde condensation product). The copolymer from Example 1 was then retanned at 30 ° C. in the same liquor with 1%, based on the solids content. After 90 mm of flexing, the leather was rewound again. The dyeing was carried out in 200% liquor with 1% of a commercially available leather dye at 40 ° C., the greasing was carried out with 4% of a commercially available fat liquor. The pH was then adjusted to 3.6 with formic acid. After a short spool, the leather was stretched out, dried, machined and pounded. A leather with good fullness and softness, very good firm grain and very good dyeing behavior was obtained, both in the surface color and in the penetration of the dye in the leather cross-section.

Comparative Example B

Analogously to Example 34, a commercial tanning agent based on acrylic acid was used instead of the product from Example 8. Compared to Example 24, the fullness, softness and color of the leather was much worse.

Claims

claims

1. Use of aqueous solutions or dispersions of copolymers

A) 5 to 95 mol% of ethylenically unsaturated mono- or dicarboxylic acids with 3 to 10 C atoms, their anhydrides, their alkali metal, alkaline earth metal or ammonium salts or mixtures thereof,

The meaning of the variables is as follows

R ^X , R ² independently of one another are hydrogen,

Ci- to Cio-alkyl, C _x - to Cio-alkoxy, Ammo, Ci- to C ₄ -alkylamino or di-Ci- to C ₄ -alkyl¬ amino,

R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ independently of one another are hydrogen, Ci to Cio alkoxy, Ammo, Ci to C ₄ alkylamino, Di-Ci bis C ₄ -alkyl¬ amino, Cζ - Cι to ₄ -aryl, C ₇ - to Cig-aralkyl, carboxyl, Ci- to C ₂₀ alkoxycarbonyl, by one to five non-adjacent oxygen atoms un terbrochenes C ₂ - to C alkyl or Sulfo or phosphono groups,

R ^{7 is} hydrogen, Ci to Cio alkyl,

Cβ - Cι to ₄ -aryl, C ₇ - to Ciβ-aralkyl or

R ^{12 is} hydrogen, Ci to Cι ₀ alkyl,

Ci to Cio alkoxy, hydroxyl or Ci to Cio acyloxy and

a, b, c, d independently of one another the number 0 or 1, where R ² and R ⁴ also together eme a 1,3- or 1,4-alkylene group with 3 to 12 carbon atoms and

C) 0 to 70 mol% of other copolymerizable monomers

or their hydrolysis products or polymer-analogous reaction products as tanning agents for tanning alone, pre-tanning and co-tanning of bare and bare fur and for retanning leather and fur.

2. Use of aqueous solutions or dispersions of copolymers according to claim 1, wherein the copolymers contain, as monomers A, acrylic acid, methacrylic acid, maleic acid, itaconic acid or maleic anhydride in copolymerized form.

3. Use of aqueous solutions or dispersions of copolymers according to claim 1 or 2, wherein the Copolymeri¬ sate as monomers B 5, 6-dihydro-4H-pyrans of the general formula la

or 2, 5-dihydrofurans of the general formula Ib

R ^θ . _^ R ⁱ²

R9 ^' OR ⁷ Ib

polymerized included.

4. Use of aqueous solutions or dispersions of copolymers according to claim 1 or 2, wherein the copolymer seeds as monomers B 6-methoxy-5, 6-dihydro-4H-pyran or

2, 5-Dιmethoxy-2, 5-dihydrofuran copolymerized.

5. Use of aqueous solutions or dispersions of copolymers according to claims 1 to 4, wherein the copolymers as monomers C methyl (meth) acrylate,

Ethyl (meth) acrylate, lauryl (meth) acrylate, butene, isobutene, 2,4,4-trimethyl-1-pentene, l-octene, C ₈ -io-01efin, 1-dodecene, Cι ₂ -ι ₄ -01efm, C ₂ o " ₂₄ -01efm, oligopropene, oligohexene, oligooctenadecene, reactive polyisobutene, methyl stearate, 2-acrylamido-2-methylpropanesulfonic acid, ethylhexylvmyl ether, styrene, acrolein or acrylonitrile contained in copolymerized form.

6. A process for single tanning, pre-tanning and co-tanning of blocks and bare fur and for retanning leather and hide, characterized in that aqueous solutions or dispersions according to claims 1 to 5 are used as tanning agents.

Copolymers

in which the variables have the following meaning

R!, R ² independently of one another hydrogen, Ci- to Cχo-alkyl, C _l " ^bls Cι ₀ -alkoxy, Ammo,

Ci to C ₄ alkylamino or di-Ci to C ₄ alkylamino,

R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ independently of one another hydrogen, Ci to Cio alkoxy, Ammo,

Ci to C ₄ alkylamino, di-Ci to C ₄ alkyl ammo, C ₆ - to Cι ₄ -aryl, C ₇ - to Ciβ-aralkyl, carboxyl, Ci- to _{C2o-alkoxycarbonyl,} by em up to five non-adjacent oxygen atoms interrupted C ₂ - to cis-alkyl or sulfo- or

Phosphono groups,

R ^{7 is} hydrogen, Ci to Cio alkyl,

C _ξ - to Cι ₄ aryl, C ₇ - to Cι ₈ aralkyl or Ci- to Cio-acyl, Ri ^{2 is} hydrogen, Ci to Cio alkyl,

Ci to Cio alkoxy, hydroxyl or Ci to Cio acyloxy ^and

a, b, c, d independently of one another the number 0 or 1, where ^¬ at

C ₎ 0 to 70 mol% of further copolymerizable monomers

with the exception of those which anhydride as the monomer A and the monomer B Malemsaure ^¬ 6-acetoxy-5, 6-dihydro-4H-pyran, 6-methoxy-5,6-dihydro-4H-pyran, 6-ethoxy-5, 6-dihydro-4H-pyran or 6-hydroxy-5, 6-dihydro-4H-pyran contained in copolymerized form, and hydrolysis products and polymer-analogous reaction products of these copolymers.