DE2404742A1 - PROCESS FOR THE MANUFACTURING OF COPOLYMERS UNSATURATED ALDEHYDE - Google Patents

Description

IiOECHST AG, - File number: - HOE lK / ¥ 031 -

Date: January 31, 1974 ~

Process for the production of copolymers of unsaturated aldehydes

It is known that unsaturated aldehydes can be homo- or copolymerized with unsaturated compounds. the Polymerizations can be carried out both in bulk and in solution, emulsion or suspension. According to these procedures becomes under the conditions of radical polymerization e.g. acrolein polymerized with or without comonomers in the presence of peroxides, azo compounds or redox catalysts.

In the bulk process, the polymer is isolated by dissolving it in an organic solvent, e.g. xylene, and subsequent precipitation in methanol.

Solution polymerization is carried out in an inert organic solvent (e.g. benzene, xylene) in the presence of a primary Polymerized alcohol; in this way gel formation is prevented and stable polymer solutions are obtained. Possibly the products can be obtained in powder form by evaporation of the solvent.

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The emulsion polymerization is carried out in an aqueous medium in the presence of redox catalysts and emulsifiers, wherein Polymer latices are obtained.

According to the suspension process, unsaturated aldehydes in an aqueous medium with free radical initiators or redox catalysts, optionally in the presence of protective colloids (e.g. polyacrylamide, methyl cellulose, alkylbenzenesulfonates), Chelating agents ^. (e.g. ethylenediaminetetraacetic acid) and metal salts (e.g. iron-II-sulfate, silver nitrate) polymerized, whereby white, powdery polyaldehydes are obtained.

If, by the suspension process, unsaturated aldehydes are copolymerized with CJβ-unsaturated monomers, which are practically insoluble in water, powdery products are formed, if at all, with smaller proportions of comonomers. If, on the other hand, the polymerization is carried out with higher comonomer proportions, for example above about 15 to 20 % , based on the total monomers, then no longer powdery suspension polymers but rubber-like, sticky materials are obtained.

Powdery copolymers have now been found, consisting of

a) from structural units of the general formula

t J- O

_C - C -
dd

R ₂ CHO

wherein R ₁ , R ₂ and R, hydrogen or each an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, two or three of these radicals may be the same, in particular wherein R ₁ , Rp and R ^ are each hydrogen

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b) from structural units of the general formula

wherein R ₁ , R _p and R, hydrogen or in each case an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, where 2 or 3 of these radicals are optionally the same, in particular wherein R ₁ , R ₂ and R-, each hydrogen, mean, and where R ^ hydrogen, an optionally alkyl-substituted or halogenated, aromatic or aliphatic hydrocarbon radical, halogen, nitrile, a carboxylate, alkylcarboxy, carboxamide, alkylketo, hydroxyl,

/means

Hydroxyalkyl or alkoxy group ^ where the aliphatic hydrocarbon radicals (alkyl radicals) each have 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, and the aromatic hydrocarbon radicals 6 to 14 carbon atoms, and the structural units b) also have more than can be of a type in which Ru has different meanings in the general formula, preferably in which Rj denotes a phenyl radical or a phenyl radical and an oxymethyl group,

and the proportion of structural units b) in the copolymer is from 20 to 60% by weight, preferably from 20 to 40% by weight.

A process for the production of aldehyde groups has also been found containing polymers by suspension copolymerization of an unsaturated aldehyde or a mixture of two or several unsaturated aldehydes of the general formula

R ₁ FU
^ C = C-CHO,
R ₂

wherein R ₁ , R _g and R, hydrogen or in each case an alkyl radical having up to 10 carbon atoms, preferably 1 to 4 carbon atoms, two or three of these radicals may be the same, in particular wherein R ₁ , R ₂ and R ^ are each hydrogen,

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mean, with a ^ ß-unsaturated compound or a mixture from two or more, ^, ß-unsaturated compounds of the general formula

wherein R ,, R ₂ and R ^, hydrogen or in each case an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, where 2 or J> of these radicals are optionally the same, in particular wherein R ,, Rp and R, each hydrogen, and where Rh is hydrogen, an optionally alkyl-substituted or halogenated, aromatic or aliphatic hydrocarbon radical, halogen, nitrile, a carboxylate, alkyl, carboxy, carboxamide, alkylketo, hydroxyl, hydroxyalkyl or alkoxy group, where the aliphatic hydrocarbon radicals (alkyl radicals) each have 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, and the aromatic hydrocarbon radicals 6 to 14 carbon atoms,

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2 4 O A 7 Λ 2

characterized,

that the polymerization is carried out in the aqueous phase at a water / monomer phase ratio of 0.5 to 2, preferably from 0.75 to 1, in the presence of 10 to 50% by weight , preferably 10 to 50% by weight, based on the amount of water , a metal salt, 0.1 to 5 wt. ^, preferably 0.5 to 1 wt. ^, based on the monomers, a suspension stabilizer, and a catalyst which decomposes into free radicals at a temperature of 20 to 150 ⁰ C, preferably 60 to 1 ^ 0 ⁰ C, performs.

Suitable for copolymerization by the process according to the invention unsaturated aldehydes are those of the general formula

\ 0> = C-CHO,
R ₂

wherein R ₁ , R ₂ and R- * are hydrogen or each an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, two or three of these radicals being possibly the same. Unsaturated aldehydes with 3 to 5 carbon atoms, for example acrolein, crotonaldehyde, methacrolein, 2-methylbutene-2-al and ^ -methylbutene-2-al, are particularly suitable.

As c ε, ß-unsaturated comonomers can be used, for example are: vinyl compounds - e.g. vinyl chloride, vinyl acetate, vinyl propionate etc., acrylic and (Xl-alkyl acrylic acids and their derivatives, such as esters, amides, nitriles, e.g. acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, methyl methacrylate, acrylamide, N-methyl acrylamide, Ν, Ν-dimethylacrylamide, acrylonitrile, methacrylonitrile etc., allyl compounds, e.g. allyl chloride, allyl alcohol, allyl acetate etc., alkyl esters of maleic and fumaric acids, vinyl alkyl ethers and vinyl alkyl ketones, e.g. vinyl methyl ether, vinyl ethyl ether, Vinyl methyl ketone, vinyl isobutyl ketone etc.

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Particularly suitable comonomers are vinyl aromatic compounds, for example styrene and cAMe thy I styrene, as well as their benzene nucleus alkylated and halogenated derivatives.

Mixtures of several monomers can also be used for the polymerization, in particular vinyl aromatic compounds in Combination with unsaturated monomers containing hydroxyl groups, e.g. allyl alcohol, polygamy as a crosslinker for the aldehyde component to serve. urotyl alcohol and methallyl alcohol,

The process according to the invention can preferably be used to copolymerize unsaturated aldehydes having J> to 5 carbon atoms which are more or less soluble in water, such as, for example, acrolein, crotonaldehyde, methacrolein, 2-methylbutene-2-al and 3-methylbutene-2-al, namely with (χΐ, β-unsaturated compounds which have practically no or only little water solubility, such as styrene or δ-methylstyrene.

In the copolymerization of sC, ß-unsaturated aldehydes with ethylenic unsaturated monomers, the components can be polymerized in any desired mixing ratios, with different Reactivities in the extreme case of pure aldehyde or pure monomer is homopolymerized. In practice you will However, the aim is to produce polymers with the most uniform possible Moiekülbau, i.e. with a largely homogeneous distribution of the individual Monomer building blocks to produce. Education uniform built-up polymer will only be guaranteed if the components are used in the "azeotropic mixing ratio" during the polymerization. are available, which is calculated from the corresponding copolytation parameters r for a given system can be. For example, for the styrene / acrolein system, the "azeotropic mixture ratio" is 75/25 parts by weight. The uniformity of the polymer structure can also be increased by feeding in individual monomers.

A monomer mixture is expediently polymerized with 10 to 60 wt. ^, Preferably 20 to 40 wt. ^, Portion anöd, ß-

unsaturated aldehydes. "

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The water / monomer ratio (phase ratio) in the The polymerization approach can be varied within wide limits. A more frequent limit of the phase relationship results from -that at a given salt concentration the consumption of metal salt increases rapidly with increasing phase ratio. On the other hand, if the amount of water used is too small, so difficulties arise in stirring; one therefore works in general within a phase ratio range of 0.5 to 2, preferably from 0.75 to 1.

A necessary prerequisite for the formation of a powdery suspension polymer is the use of a metal salt, which is dissolved in water as a suspension medium. If the polymerizations are carried out without added metal salts, then not powdery polymers, but rubber-like, sticky masses obtained.

Salts suitable for use in the process according to the invention must have sufficient water solubility and must not interact with the protective colloid, which can lead to precipitation and clumping of the dissolved protective colloid. On the one hand, the dissolved salts reduce the solubility of the monomers in water and, on the other hand, the protective colloid remains completely dissolved even at higher salt concentrations. Compounds that meet this requirement are, in particular, the alkali metal salts of mineral acids, such as lithium chloride, sodium chloride, sodium phosphate , potassium chloride, potassium bromide, etc.

The salts are preferably in water before the polymerization dissolved and 'optionally filtered, provided that it is technical grade salts. The concentrations of the Salt solutions are of minor importance for the formation of the suspension polymer and can accordingly be used in further limits can be varied; the upper limit of the concentration is generally determined by the saturation concentration of the relevant salt, down through a critical concentration

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tion established, with v / elcher just still suspension polymer is formed, ie with approx. 8 wt. % metal salt; the concentrations are 10 to 50% by weight , preferably 10 to 30% by weight , based on the suspension medium (water).

Organic macromolecules are used as suspension stabilizers, which have surface activity and have hydrophilic groups so that they are soluble in water. Farther The water solubility of these polymers must be sufficiently high so that they can be used by the process according to the invention Salts are not precipitated in the polymerization plot and thus lose their effectiveness as a protective colloid

/ for example would. Properties of the type mentioned have / the compound class of polyvinylamides, for example poly-N-vinyl acetamide, PcIy-N-vinyl propionamide, poly-N-vinyl butyramide and cyclic polyvinyl amides, for example poly-N-vinylpyrrolidone. Good characteristics as suspension stabilizers have in particular copolymers containing more than 90 $> consist of poly-N-vinyl-N-alkylamides next few percent Acrylsäureestera. Copolymers of 90 to 99 * 9 % poly-N-vinyl-N-methyl-acetamide and 10 to 0.1 % 2-ethylhexyl acrylate are particularly advantageously used. Of course, copolymers of higher alkyl-substituted acid amides (e.g. N-vinyl-N-methylpropionamide, N-vinyl-N-ethylbutyramide) and esters of o £, ß-unsaturated carboxylic acids and dicarboxylic acids of the general formulas:

' ^0R 6' in R ₇ -C-COOR ₉ Rg, R ₉ and R. CH _O = CR _C -C ' will, I '
Rg-C-COOR ₁₀ used where R ^, Rg, R ₇ , I ₀ water

substance, a straight-chain or branched, substituted or unsubstituted alkyl radical with 1 to 10, preferably 1 to ^, carbon atoms, two or more of these radicals can also be the same.

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The amounts of suspension stabilizer used for the polymerization are in the range from 0.1 to 5% by weight, preferably from 0.5 to 1% by weight , based on the monomers. It is expedient to proceed in such a way that the desired amount of stabilizer and salt is dissolved in the suspension medium water and this solution (liquor) is placed in the polymerization flask. The monomer which contains the catalyst in dissolved form is then added with stirring. If necessary, only part of the protective colloid can be initially dissolved in the liquor, and the remainder is added in the course of the polymerization.

As polymerization catalysts compounds may be used which decompose below about 150 ⁰ C in radicals. These are in particular peroxides, e.g. t-butyl peroxide, di-t-butyl peroxide, dicumyl peroxide, lauroyl peroxide, propionyl peroxide, benzoyl peroxide, t-butyl peroxy isobutyrate, t-butyl percctoate, t-butyl peracetate, t-butyl peroxycrotonate, e.g. od ^! -Azo-di- (isobutyronitrile), <y-, ~ P -Azo-di - (- ^ - cyanovaleric acid) etc. The catalysts are used in small amounts, which depend on the type of catalyst and the reaction temperature; in general, 0.05 to 5% by weight, preferably 0.1 to 1% by weight, based on the monomer.

The polymerization temperatures can also be varied within wide limits and depend in particular on whether the polymerization is carried out under atmospheric pressure or under higher pressure. In the case of polymerization under atmospheric pressure, the reaction temperature is determined by the boiling point of the lowest-boiling component, according to which optimal catalysts can be selected accordingly. In general, one will polymerize at temperatures from 20 ° to 150 ⁰ C, but preferably from βθ to 130 ⁰ C, with a corresponding pressure the boiling points of the components is established.

The polymerization is expediently carried out under an inert gas atmosphere executed; to do this, the reaction mixture is flushed with nitrogen, helium or carbon dioxide.

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The polymers are advantageously worked up by pouring the entire polymer suspension into water, Allow to settle and the supernatant, diluted liquor decanted off. In this way, a large part of it gets solved Metal salt removed. Of course, the polymer can also be separated from the liquor by filtration or centrifugation will.

advantageous

Further purification takes place by steam distillation with stirring and subsequent filtration; this method is used to remove unreacted monomer components and further metal salt. It is then advantageously dried under reduced pressure at temperatures of preferably from 50 to 60.degree. White, fine-grained, powdery and free-flowing polymers are obtained.

The technical progress of this process is thus that under the conditions of free radical polymerization in an aqueous medium, the reaction can be carried out in a simple manner by adding certain Metal salts can be controlled so that you do not get sticky, rubbery masses, but powdery suspension polymers.

A further advantage is that the polymerizations with small phase ratios, relatively short polymerization times and good yields occur, so that aldehyde-group-containing polymers with high space-time yields are obtained by this process can be produced.

The inventive method can be unsaturated Aldehydes copolymerize with ethylenically unsaturated compounds, as a result of which polymers are obtained which have the aldehyde groups further reactions are accessible.

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It is "known that by polymerization of unsaturated Aldehydes produce polymers that contain free aldehyde groups and other reactions typical for aldehydes, • are accessible. For example, these polymers can become water-soluble through the action of sulfurous acid or through reaction with monovalent ones Alcohols are acetalized or crosslinked with polyhydric alcohols. Leaves solutions containing the aldehyde groups When polymers act on substances that have OH groups, acetalization causes the polymer to bond chemically to the fabric. In this way, for example, textiles, skins, leather, paper, etc. impregnate.

Another field of application for polymers containing aldehyde groups consists in the production of thermosetting films and molding compounds by mixing with polyols or containing OH groups Connections, creating products with improved mechanical and thermal properties.

The polymers of unsaturated aldehydes produced by the process of the invention have free aldehyde groups in the macromolecule: a styrene / acfolein copolymer produced according to Example 1 shows ^/ carbpnyl band at 170 cm in the infrared spectrum. Furthermore, the reaction with fuchsin sulphurous acid gives the color reaction typical of aldehyde groups; a blue-colored polymer is obtained which does not lose its color even after prolonged treatment with water. The unsaturated aldehydes are thus largely polymerized in via the CC double bond.

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Examples
Comparative example

For cleaning purposes, acrolein is distilled over copper shavings under nitrogen.

1500 g of water were placed in a ^ liter four-necked flask flushed with nitrogen and equipped with a stirrer, reflux condenser and thermometer and, with stirring, 7 * 5 g of suspension stabilizer A1 (copolymer of 99% by weight of polyvinyl methylacetamide and 1% by weight of # 2-A ' ethylhexyl acrylate; K value: 85). The mixture was heated to 70 ° C. with stirring and nitrogen passed through, then 1128 g (75% by weight ) of styrene, 372 g (25% by weight) of acrolein and 3 g of azodiisobutylronitrile were added and polymerization was carried out at this temperature. After about 2 hours, a highly viscous polymer formed and after 2 1/2 to 3 hours led to clumping of the batch with the formation of a rubber-like, sticky mass which was finally discarded.

A 10 liter four-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blanket was charged with a 26% strength (saturated) salt solution consisting of 2665 g of water and 935 g of sodium chloride. With stirring, was 18 g of suspension stabilizer A 1 and heated with stirring and nitrogen bubbling at 70 ⁰ C. Once this temperature was reached, was added 2,700 g (75 wt. ^) Of styrene, 900 g (25 wt.%) Acrolein and 7.2 g azodiisobutyronitrile to and polymerized under a blanket of nitrogen for 8 hours at 70 ⁰ C and 2 Stunlen at 80 ⁰ C. During this reaction time a fine-grain white powder precipitated. After a total of 10 hours, the mixture was cooled, the polymer suspension was poured into 10 liters of water and the polymer was allowed to settle. The supernatant solution was then decanted off and the polymer was subjected to a 5-hour steam distillation to remove residual monomers; it was then filtered and dried at approx. 40 ° C. in vacuo.

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3393 g (9 % yield) of a white, powdery polymer were obtained which was insoluble in most organic solvents such as benzene, toluene, acetone and chloroform. On heating, it dissolved in ethylbenzene and dimethyl sulfoxide. The styrene / acrolein copolymer showed the following characteristics: RSV: 0.30 dl / g (measured on a solution of 1 g of the polymer in 100 ml of dimethyl sulfoxide at 25 ^° C.)
Grain size: 25 to 250 u

Vicat softening point: 95 ° C (according to DIN 53 ^ 60 in air) Glass temperature Tg: 79 ° C.

Beisgiel_2

123 g of sodium chloride were dissolved in 1110 g of water (10% strength by weight solution), 7 * 5 g of suspension stabilizer A1 were added and the mixture was heated to 70.degree. After reaching this temperature, 1128 g (75 wt. ^) Styrene (25 wt ^.) Acrolein gave 372 g and 7.5 g of lauroyl peroxide to and polymerized for 8 hours at 72 ⁰ C and 2 hours at 80 ⁰ C. After a total of The reaction time was 10 hours and the polymer was worked up as described in Example 1; Yield: 1396 g (93 %)

Belsgiel_3

There are (15 wt ^ solution.) 225 g of sodium chloride in 1275 g water "dissolved and I5 g of a commercially available polyvinylpyrrolidone (K-value: 90) was added after a temperature was reached of 70 ⁰ C, was added 1128 g (75. wt. ^) of styrene, 372 g (25 ^) acrolein wt. and 7 * 5 g of lauroyl peroxide to and polymerized for 6 hours at 72 ⁰ C and 3 hours at 8l ° C. After 9-hour reaction time, the polymer was worked up in the manner described. 1390 g (93 %) of white, powdery polymer with the following characteristics were obtained: RSV: 0.22 (dl / g), Vicat softening point: 90 ° C., Tg: 79 ° C.

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Example_4

A solution of 150 g of potassium bromide in 600 g of water was placed in a 2 liter four-necked flask (20% strength by weight solution); 7.5 g of suspension stabilizer A 1 were added to this. ^{A mixture of 56 2} J g styrene, 186 g acrolein and 3 × 75 S lauroyl peroxide was allowed to run in with stirring and polymerization was carried out at 72 ° C. for 6 hours and at 80 ° C. for 2 hours. After cooling to room temperature, it was worked up in the usual way; Yield: 69O g = 92 $>.

Beisgiel_5

The polymerization was carried out as set out in Example 4 using primary sodium phosphate instead of potassium bromide. 65O g (86.5 %) of a styrene / acrolein copolymer were obtained.

Beisgiel_6

In a 6-liter four-necked flask was added a saturated (26 wt. ^ Strength) solution of 585 g of sodium chloride in water and added 11.3 g I665 S Suspensicnsstabilisator A 1 added. After the temperature had reached 70 ° C, I615 g (72 wt.%) Styrene, 525 g (23 wt. ^) Acrolein and 110 g (5 wt. ^) Of allyl alcohol was added and g by addition of ¹ I ^ azodiisobutyronitrile Polymerized at 70 ° C. for 8 hours and at 80 ^{° C. for 2 hours.} After a total of 10 hours of polymerization time, the product was cooled and worked up in the manner described. 1930 g (86 ^) of a styrene / acrolein / ayl alcohol terpolymer were obtained.

/ one
RSV: 0.14 dl / g (measured on ⁷ solutions of 1 g of the polymer in

100 ml dimethyl sulfoxide at 25 ° C) Vicat softening point: 92 ° C
Tg: 87 ⁰ C

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Claims (1)

hoe 031 Patent claims: 1. Powdered copolymers consisting of " a) from structural units of the general formula where R ,, R ₂ and R ^, hydrogen or in each case an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, two or three of these radicals may be the same, in particular where R ₁ , R ^ and R. are each hydrogen, mean, • Λ IAl. i \ A J. L-Jf and b) from structural units of the general formula σ
ι Ri, wherein R., R ₂ and R-, hydrogen or in each case an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, where 2 or J> of these radicals are optionally the same, in particular wherein R ₁ , R 2 and R-, respectively Hydrogen, and where R ₁ , hydrogen, an optionally alkyl-substituted or halogenated, aromatic or aliphatic hydrocarbon radical, halogen, nitrile, a carboxylate, alkylearboxy, carboxamide, alkylketo, hydroxyl, hydroxyalkyl or alkoxy group / , the aliphatic hydrocarbon radicals (alkyl radicals) each having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, and the aromatic hydrocarbon radicals 6 to 14 carbon atoms / b) have atoms, and the structural units / can also be of more than one type * in which R ₁ , in the general paragraph, has different meanings, preferably in which - 16 '509832/0857 - 16 - HOE 7V? 031 R ₂ denotes a phenyl radical or a phenyl radical and an oxymethyl group, and the proportion of structural units b) in the copolymer is from 20 to 60% by weight, preferably from 20 to 40% by weight. Process for the preparation of polymers containing aldehyde groups by suspension copolymerization of an unsaturated aldehyde or a mixture of two or more unsaturated aldehydes Aldehydes of the general formula ^R i ^R - *
4 »3 C = C-CHO, wherein R ₁ , Rp and R_ are hydrogen or in each case an alkyl radical having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, two or three of these radicals may be the same, in particular wherein R., Rp and R ^, each denote hydrogen, with an oC, ß-unsaturated compound or a mixture of two or more ^, ß-unsaturated compounds of the general formula where R ₂ ^ is hydrogen, an optionally alkyl-substituted or halogenated, aromatic or aliphatic hydrocarbon radical, halogen, nitrile, a carboxylate, alkylcarboxy, carboxamide, alkylketo, hydroxyl, hydroxyalkyl or alkoxy group, the aliphatic hydrocarbon radicals (alkyl radicals ) each have 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, and the aromatic hydrocarbon radicals 6 to 14 carbon atoms,
characterized, - I ₇ - 509832/0857 - 17 - 'hoe 7Vf 031 wherein the polymerization in aqueous phase at a phase ratio water / monomer of 0.5 to 2, preferably 0.75 to 1, in the presence of 10 to 50 wt.% _s preferably 10 to 50 wt.% j based on the amount of water, a metal salt, 0.1 to 5 wt.%, preferably 0.5 to 1 wt $ _o, based on the monomers, of a suspension stabilizer and a decomposing into radicals ¹ catalyst at a temperature of 20 to 150 ⁰ C, preferably 60 to 150 ⁰ C ₅ performs. J>. Process according to Claim 2, characterized in that the metal salt used is an alkali metal as a mineral acid. 4. The method according to claim 2, characterized in that sodium chloride is used as the metal salt «, 5. The method according to claim 1, characterized in that one a polyvinylamide is used as a suspension stabilizer. 6. The method according to claim 2, characterized in that one copolymerized a monomer mixture of acrolein, styrene and allyl alcohol. ORIGINAL INSPECTED 5 09832 / 08B7