DE1570254B1 - PROCESS FOR PRODUCING MIXED POLYMERISATES - Google Patents

Description

1 2

The present invention relates to a method zol (3) and - optionally - the other co-

for the production of copolymers, the monomeric (4) to be mixed-polymerized and in the mixed

1) 0.9 to 1.2, in particular 1 to 1.1, mol of a polymer containing up to N-hyacrylic acid from the N-hydroxymethylamide of the N-2-oxaalkylamides of acrylic and / or methacrylic or methacrylic acid to 9 carbon atoms in the ⁵ droxymethylamide groups by means of an alkanol or oxaalkvlrest oxaalkanol to form N-2-oxaalkylamide groups

'ether. The disadvantage of this process is that

2) at least 0.001 mol of an α-ethylenically unsaturated N-hydroxymethyl amide of acrylic or methacrylic saturated, mono- or dibasic carboxylic acid in separate - with yield losses with up to 6 carbon atoms and / or an i ₀ bound - process from acrylic or methacrylic alkyl or oxaalkyl half esters of such an acid amide and paraformaldehyde and divalent carboxylic acid with up to 9 carbons must be worked. Another disadvantage is that in the case of material atoms in the alkyl or oxaalkyl radical, _re i _a tively large amounts of the N-hydroxymethylamide

3) an alkyl or oxaalkyl ester of acrylic and / of acrylic or methacrylic acid while poly- or methacrylic acid with up to 20 carbon ¹ S merization occurs slightly crosslinking. Although it can atoms in the alkyl or oxaalkyl radical and / or be suppressed by working in the presence of a vinyl or alkylvinylbenzene with up to ^of free paraformaldehyde, this then interferes with 12 carbon atoms and possibly also in ^the products, especially during their processing , in addition, will the result of networking (tendency towards

..., .. ,, ·, ... ^, ²⁰ solubility of the products) is reduced by

4) em another athylenically unsaturated comono- _the copolymers with relatively low mol-

^{If more} weight is produced, it occurs again

- The amounts of the components under 1) other disadvantage: In the case of the relatively low molecular weight 4) In parts by weight 1) 4 to 45, in particular 8, granular polymers are the application-related ones up to 30 parts, 2) 0.1 to 12.5, in particular 0.5 to 25 properties are generally unsatisfactory.

7 parts, 3) 20 to 90, especially 68 to 85 parts and The third method consists essentially in

4) not more than 30, in particular not more than the N-2-oxaalkylamide of acrylic or methacrylic acid

Make up 15 parts - included in polymerized form. with the carboxylic acid and / or the alkyl or oxa

Polymeric substances of the type indicated are known; alkyl half ester (2), the alkyl or oxaalkyl ester they are used in particular as binders. 30 and / or vinyl or alkylvinylbenzene (3) as well as Each depending on the type and amount of their - if necessary - the other comonomer (4) building components are suitable, for example, for mixed polymerisation. The disadvantage of this stoving enamel, Impregnating agents or adhesives. drive is also that the N-2-oxaalkylamide

To produce the polymeric substances are in the acrylic or methacrylic acid in separate - with

Practice four procedures become known. 35 Yield losses associated - procedure

The first process essentially consists in using acrylic or methacrylic acid amide, paraformaldehyde

Acrylic or methacrylic acid amide and an alkanol or an oxaalkanol

m "NT m rcrvf Λ - γη ^and must be eitet ^{on eart} g>.

IH ₂ JN _ ^ u UCu ₃ J - LH _{2 The fourth} method consists essentially of:

_ 40 the polymerization reaction, the alkylolation of the

H ₂ JN - CO-CH = CH ₂ ) amides and etherification of the alkylolamides side by side

to run with the carboxylic acid and / or the alkyl or other in the same reaction vessel Oxaalkyl half ester (2), the alkyl or oxaalkyl ester ("one-pot reaction"). Disadvantage of this process and / or the vinyl or alkylvinylbenzene (3) and is that inhomogeneous products with unrelated

- if necessary - to polymerize the other comonomer (4) 45 satisfactory and poorly reproducible self-mixing, in the mixed polymer that leads to what may be explained by it Acrylic or Methacrylic acid amide-derived amide, that once the number of in the polymerization groups by means of paraformaldehyde in N-hydroxy competing monomers by the simultaneous transfer methylamide groups and these by means of the presence of unchanged, alkylolated and of an alkanol or oxaalkanol to form N-2-oxaalkylamide-50 oxaalkyl-substituted acid amide by two comono groups to ethereal. The disadvantage of this process is that it has different reactivities in a fluctuating conist, that when working with relatively small amounts, the concentration is increased, on the other hand, the alkylolie-paraformaldehyde not only N-hydroxymethylamidation reaction and the etherification reaction subgroups arise, but also Ν, Ν'-methylene require different reaction conditions. the bisamide groups can form, as a result of which the 55 process products almost always contain shares of Copolymers are crosslinked and highly viscous crosslinked copolymers.

soluble to insoluble products arise. The present invention provides a new one

Working with relatively large amounts of paraformaldehyde method demonstrated with which it in practical, the formation of Ν, Ν'-methylenebisamide can be technically advanced compared to the known processes to push back, however, a step-by-step approach is possible, copolymers Another disadvantage: Products are obtained that can be manufactured of the type specified at the beginning. Through the the substantial amounts of free formaldehyde produced In particular, a new process will be halted or hand in when storing. shown, which is designed as a "one-pot process" The second method essentially consists in largely eliminating the disadvantages outlined above .bis the N-hydroxymethylamide of acrylic or meth- 65 can be completely avoided, acrylic acid with the carboxylic acid and / or the alkyl accordingly is the subject matter of the invention or oxaalkyl half esters (2), the alkyl or oxa process for the production of copolymers, alkyl esters and / or the vinyl or alkyl vinyl benzene

ORiGiNAL INSPECTED

1) a total of 0.9 to 1.2 moles of an N-2-oxaalkylamide acrylic and / or methacrylic acid with up to 9 carbon atoms in the oxaalkyl radical,

2) at least 0.001 mol of an ethylenically unsaturated, mono- or divalent carboxylic acid with up to 6 carbon atoms or mixtures thereof and / or an alkyl or oxaalyl half ester of such a divalent carboxylic acid with up to 9 carbon atoms in the alkyl or oxaalkyl radical or mixtures of these half-esters,

3) an alkyl, oxaalkyl acrylate, alkyl, oxaalkyl methacrylate with up to 20 carbon atoms in the Alkyl or oxaalkyl radical or mixtures of these esters and / or styrene or alkyl styrenes with up to to 12 carbon atoms or mixtures thereof and optionally additionally

4) another ethylenically unsaturated comono-

meres

20th

- The amounts of the components under 1) to 4) in parts by weight 1) 5 to 45 parts, 2) 0.1 to 12.5 parts, 3) make up 20 to 90 parts and 4) not more than 30 parts - contained in polymerized form, by reacting of acrylic or methacrylamide with paraformaldehyde and an alkanol or oxaalkanol and the under 2) to 4) mentioned monomers with polymer formation in the presence of customary aliphatic azo compounds as polymerization initiators, which is characterized in that one

A) in a first process stage

a) 0.9 to 1.2 mol of acrylic or methacrylic acid amide,

b) 0.9 to 1.2 mol of paraformaldehyde (calculated as monomeric formaldehyde),

c) at least 0.9 mol of an alkanol or oxaalkanol containing up to 8 carbon atoms as

d) 0.001 to 0.5 mol of a tertiary, aliphatic having up to 12 carbon atoms Monoamine

holds in an oxygen-containing atmosphere for a time of 15 to 120 minutes at a temperature of 50 to 100 ⁰ C,

B) in a second process stage of the carboxylic acid and / or the half-ester (2) the total amount or a partial amount, but at least 101 equivalent percent - based on the monoamine (d) - is added for a time of 1 to 24 hours at a temperature of 80 to 140 ⁰ C holds and

C) in a third process stage - if appropriate - the remaining amount of the carboxylic acid and / or of the half ester (2), the ester and / or the styrene or alkylstyrene (3) and - if appropriate - the other comonomer (4) is added and in the presence of an aliphatic azo compound as a polymerization initiator copolymerized.

An advantageous embodiment of the method according to the invention is characterized in that stage as a carboxylic acid (2) in the second process ⁶ S (B) maleic acid and used in the third process stage (C) acrylic acid. - The advantage of this procedure is, inter alia, that it can be used to obtain polymeric substances which give particularly clear solutions in organic solvents.

Another advantageous embodiment of the method according to the invention is characterized in that that as monomer (3) 20 to 70, in particular 20 to 40 parts by weight of the 2-ethylhexyl ester of acrylic acid begins. - The advantage of this procedure is, among other things, that it is polymeric Substances can be obtained which have a particularly good pigment carrying capacity and which are particularly are suitable for stove enamelling with high resistance to condensation water, salt solutions and basic substances.

Another advantageous embodiment of the method according to the invention is characterized in that that as monomer (3) 20 to 70, in particular 20 to 50 parts by weight of the methyl ester of methacrylic acid and / or the tert-butyl ester of acrylic acid is used. - The advantage of this approach is, inter alia, that after it polymeric substances can be obtained which are particularly suitable for electrophoretically depositable stoving enamels (bath stability) and for stoving enamels that have a high resistance to the effects of weather.

Another advantageous embodiment of the method according to the invention is characterized in that that as comonomer (4) 2 to 20, in particular 5 to 12 parts by weight of the monoester of acrylic acid starts with 1,4-butanediol. - The advantage of this approach is, among other things, that after it polymeric substances can be obtained with etherified Aminoplast condensates are particularly well tolerated and at relatively low temperatures harden are.

The following can be said in detail about the starting materials for the process according to the invention:

a) Methacrylic acid amide is suitable

(H ₂ N - CO - C (CH ₃ ) = CH ₂ )

Acrylic acid amide (H ₂ N - CO - CH = CH ₂ ) and mixtures of these amides.

b) The commercially available paraformaldehyde is suitable. It is particularly useful to use an unstabilized Use paraformaldehyde, the molecular weight of which is in the range from 150 to 1200 lies.

c) Suitable alkanols are the customary, in particular the primary QC ^ alkanols, such as methanol, ethanol, n-propanol and n-butanol; also C ₅ -C ₈ alkanols, such as η-amyl alcohol, i-amyl alcohol, neopentyl alcohol and 2-ethylhexanol; suitable oxaalkanols are, for example, 3-oxabutanol, 3-oxapentanol, 3-oxaheptanol, 3,6-dioxaheptanol and 3,6-dioxadecanol. Mixtures of alkanols and / or oxaalkanols are also suitable.

d) Particularly suitable monoamines are those whose pKb value is less than 5.5. examples for suitable monoamines are trimethylamine, triethylamine, tributylamine, Ν, Ν-dimethyl-N-cyclohexylamine and N, N-dimethyl (/ 3-hydroxyethyl) amine. Mixtures of monoamines are also available suitable.

5 6

2) As carboxylic acids and alkyl or oxaalkyl. The atmosphere containing oxygen can The usual ones are most suitable; on the part can be easily maintained by a of the carboxylic acids, for example maleic acid, fumaric oxygen-containing gas via the conversion acid, acrylic acid and methacrylic acid; on the part of which is well managed. It has proven to be useful Alkyl or oxaalkyl half esters, for example, the half 5 if the atmosphere is 10 to 30 percent by volume of acid esters of maleic and fumaric acid with methanol, substance and otherwise an inert gas such as nitrogen, ethanol, n-propanol, i-propanol, amyl alcohol, 3-oxa holds. It has also proven to be useful at times pentanol and 3,6-dioxaheptanol. Mixtures of minor amounts (no more than Carboxylic acids and / or alkyl or oxaalkyl half- 30 percent by weight, based on the acrylic and / or esters are suitable. 10 methacrylic acid amide) of amido or imido stick

3) As alkyl or oxaalkyl esters of the ethylenically unsaturated ones containing acrylic and / or material atoms Methacrylic acid are also suitable to work with the relevant compounds that work with acrylic and / or usual, for example the methyl ester of meth-methacrylic acid amide are not identical. In the end acrylic acid and the ethyl, n-propyl, i-propyl, it goes without saying that a relatively short Umn-butyl, i-Butyl, tert-butyl and 2-ethylhexyl esters have a relatively high reaction temperature of acrylic acid. Furthermore, for example, the one to be assigned and vice versa are suitable.

3-oxabutyl, 3-oxapentyl, 3-oxahexyl, 3-oxaheptyl, the second stage of the process can also

3,6-Dioxaheptyl-, 3,6-Dioxaoctyl-, 3,6-Dioxanonyl-, expediently with stirring of the reaction mixture

and 3,6-dioxadecyl esters of acrylic or methacrylic be carried out. It has proven to be advantageous

acid. Mixtures of alkyl or oxaalkyl esters in the presence of a polymerization inhibitor are also added

are suitable. work; as such, the usual, e.g.

As vinyl or alkyl vinyl benzenes, phenothiazine, hydroquinone, methylene blue,

for example styrene and also, for example, o-, m-nitrosophenol and m-dinitrobenzene, in amounts of

and p-methylstyrene. «-Alkylstyrenes are also suitable- 0.001 to 0.1 percent by weight (based on the in the

if, however, in general, it is advisable to use 25 first stage acrylic and / or methacrylic

can only be used in subordinate quantities. acid amide). Provided the implementation in the present

Mixtures of vinyl or alkyl vinyl benzenes in relatively large amounts of a solvent also take place,

are suitable. It has proven to be useful, and is usually recommended, at the boiling point of the ambient

if the alkyl groups of the alkylvinylbenzenes do not work well, solvents evaporate

have more than 3 carbon atoms. 30 and - if necessary - the solvent after

4) As other comonomers, in turn, sen condensation and removal of water are suitable in the usual way. Of these, settlement material should be emphasized. Apart from that, with regard to the reaction time and the reaction with C ₂ -C ₄ alkanediols, vinyl esters of the QQ alkane temperature, the same applies to the monoesters of acrylic and / or methacrylic acid as in the first stage of the carboxylic acids and the so-called "Versatic acids" 35.

and the nitrile of acrylic and / or methacrylic acid. In the third stage of the procedure, the Um-Further For example, the amide and N-hydrogenation material are suitable, the remaining monomers, the azoverdroxymethylamide the acrylic and / or methacrylic acid bond and - if necessary - other solutions as well as other copolymerizable compounds with agents in each case in their total amount or in time

Amido or imido nitrogen atoms. Mixtures 40 successive partial amounts are also added. As azo

of comonomers are suitable. Connections are the usual ones, for example

To the proportions of the starting materials azodiisobutyric acid nitrile, azodiisobutyric acid amide

is to be said in detail that it is useful if and azodicyclohexyl carbonitrile, in amounts of about

the molar ratio of acrylic and / or methacrylic 0.3 to 5 percent by weight (based on the total

acid amide (a) to paraformaldehyde (b) 1: 1 or about 45 weight of the monomers). It can be useful

smaller - ■ about 1: 1.2 - and the molar ratio in the presence of additional auxiliaries, such as MoIe-

from acrylic and / or methacrylic acid amide (a) to alkaline weight regulators to work,

nol or oxaalkanol (c) also 1: 1 or less.

- until about 1:15 - is. The monoamine (d) and the polymeric substances held can in particular be used as

Carboxylic acid or the alkyl or oxaalkyl half-binders are used. Each dependent

Esters (2) must always be used in such amounts, depending on the type and amount of their constituent components

be that the carboxylic acid component (2) is less suitable, for example, for baking enamels, im-

at least 101 equivalent percent of the monoamine. impregnating agents or adhesives. Unless the polymer

The three stages of the process according to the invention, substances relatively large amounts of strongly polar monomers,

in particular the second and third stages, such as carboxylic acids and / or alkyl or oxaalkyl

moderately polymerized in the presence of an organic Lö- halester (2), they can

solvent carried out. Suitable as such are expediently by means of a nitrogen base in

particular excess amounts of the alkanol or an aqueous medium are taken up; she

Oxaalkanols (c) as well as benzene and C ₁ -C ₃ -AIlCyI- are in this form by means of electrophoresis on elec-

benzenes. Mixtures of solvents can also be separated from 60 trically conductive objects, which

suitable. is particularly advantageous for stoving enamels.

As a device for carrying out the process The parts and percentages given in the examples

apparatus of the usual design are suitable, in particular refer to the weight,

those with stirrer, reflux condenser or water.

ejectors, gas supply line as well as filling and filling pre- 65 Example 1

directions are provided. A) In one equipped with a stirrer and reflux condenser

The first stage of the process can be more conveniently see 6.1 parts of acrylic acid amide

wise carried out with stirring of the reaction mixture (a), 2.6 parts of paraformaldehyde (b), 6.5 parts

7 8

n-butanol (c) and 0.08 part Ν, Ν-dimethyl-N- precipitation - as long as it is at boiling point

(jff-hydroxyethyl) amine (d) contained in an oxygen until 6 parts of water are separated,

holding atmosphere for 1 hour boiled down to 9O ⁰ C Q Then, 3 parts of acrylic acid (2),

hold (agitation speed 40 rev / mm). _{180 Tdle tert} ._ Butylacrvlat _{(3)> 36 parts 2} . _Ät ii _yl .

B) Thereupon 0.25 parts of maleic acid (2), ⁵ hexyl acrylate (3), 60 parts of n-butoxymethyl meth-42 parts of n-butanol and 0.005 parts of phenothiazine acrylic acid amide (4), 54 parts of azodiisobutyric acid are added, after which the reaction mixture is nitrile and 3 , 5 parts of tert-dodecyl mercaptan added stirring is kept at 90 ° C. for 3 hours. give, after which it is slowly brought to 90 ° C.

C) Then 2.5 parts of acrylic acid (2), _{10 as} soon as the reaction starts (heat-30 parts of 2-ethylhexyl acrylate (3), 5 parts of styrene (3), development), it is cooled so that the temperature 7 , 8 parts of 1,4-butanediol monoacrylate (4) (45% in the reaction mixture remains 90 ° C. After 2 hours 1,4-butanediol), 0.3 part of azodiisobutyronitrile ^{is then} ~ ^be ! ^{90 C u} P ^d "^ total five- and 1.75 parts of tert-dodecyl mercaptan were added, f ^{al" m} intervals of 1 hour each after which the Umsetzungsgut with stirring for 6 STUN ₁₅ ^{1 T} f ^ü Azodiisobuttersäuremtnl added woden to 9O ⁰ C. Under the same conditions ^{after a further 6 hours at 90 ° C., the} resulting polymer (in the form of a solution) five times in total, is suitable as a binder for a weather-resistant hour 0.3 each time Parts of azodiisobutyronitrile for stoving finishes.

given, after which another 6 hours at 90 ° C _a o

is held. Example 4

The polymer obtained (in the form of a solution) ^The polymers are produced in 1-1 col-

Material is ideal as a binder for input ^{ben au. s ΟΜ8} \ ".., _", .. ,, ^ ₁ . ""_"R burning coatings, can be deposited in particular for pigmented electrophoretic Jn 'nem with Ruckfmßkuhler Zulaufgefaß, Wasserretisch baking finishes. ²⁵ separator and stirrer equipped reaction vessel

40.7 parts of acrylamide, 17.2 parts of paraformaldehyde

Example 2 ⁿ yd, 40.0 parts of n-butanol and 0.5 part of dimethyl

Ethanolamine poured into the flask and 1 hour

A) Stirred ^{at 90 °} C. in one with a stirrer and water separator. Then, 130 parts of n-butanol, provided vessel, 45.2 parts acrylic acid ₃₀ 130 parts of xylene, 1 part of maleic acid and 0.05 parts of amide (a), 21 parts of paraformaldehyde (b), 48 parts of hydroquinone were added and further stirring n-butanol (c), 0.5 part of N, N-dimethyl-N - (^ - hy- the mixture is heated to boiling temperature. During this process, hydroxyethyl) amine (d) and 100 parts of xylene are removed from the system under water. After 7 parts have separated off, a gentle stream of air is passed over the water for 1 hour, and the process is ended. The total duration stirred at 90 ⁰ C. ₃₅ circling the water: 1.5 hours.

B) Then 1 part of maleic acid (2), 146 parts of 111 parts of ethyl acrylate, 93 parts of n-butanol, 46 parts of xylene and 1 part of phenostyrene, 6 parts of acrylic acid, 4 parts of tert-dodecylmerthiazine are added and stirring with a captan and 1 part azodiisobutyronitrile added temperature of about 110 to 130 ⁰ C solution and then heated to 90 ° C (with stirring). After the medium has evaporated, after condensation and 4o 2 hours, 1 part of azodiisobutyronitrile is added again to the water contained in it, a further part after 3, 4, 5 and 6 hours. is returned to the reaction vessel. After the last addition, it is 6 hours at 90 ⁰ C, polymerization is continued at the specified temperature for a time. The temperature of the polymeric contents until 10.8 parts of water have been removed. sizing solution can be achieved by moderate cooling and

_ ,. . ,,. “Jj ctm a 1 - _w 45 heating, as required, slightly on the intended

^C) ÄÄ ^ ^ -> JJ ^ λ ^Ac 5. ^yl Ti, ^{e (} 'level of 90 ° C. It is a poly-249 parts of styrene (3) 3 5 parts of azodicyclohexyl _{merisate solution with an} outflow time, measured in carbomtril and 3 parts of tert-dodecyl mercaptan _DIN . _Bec her with the nozzle 6, obtained from 37 seconds, after which the reaction product 10 hours _{(after mN 53 m)} _

which is kept at 90 C. It will then be ₅₀

Another 1.5 parts of azodicyclohexylcarbonitrile were added to the comparative experiment for example 4, after which the _{apparatus described in} example 4 was kept at 90.degree. C. for a further 6 hours. _{172 parts of the} p _ara f _ORMA idehyd, 130.0 parts of n-butanol, the (in the form of a solution) obtained polymer and 130.0 parts of xylene heated to reflux. Fabric is a valuable binder, especially for 55 Now a mixture of 111.0 parts of ethyl acrylate, stoving enamels. 93 parts of styrene, 6 parts of acrylic acid, 4 parts of tert-dodecyl mercaptan, 40.7 parts of acrylamide, 0.5 parts of Example 3 dimethylethanolamine and 1 part of azodiisobutyric acid

A) In an added with stirrer and water comparable _c nitrile. After 2 hours, 31 parts of methacrylic acid are ^started with the addition of azodiisobutyronitrile amide (a), 11.7 parts of paraformaldehyde (b), ™ ^{d wei} i. ^er ^ ^h ^ ^{a as in the} previous example 26 parts of n-butanol (C) and 0.5 parts of N, N-Di- described. The temperature of the solution is, however, -hydroxyäthyl methyl-NQ?) -Amine (d) 1 hour? °, f ^ \ ^ ^{da Standl} S Y ^ass ™ stirred ^under § ^ ^ek st is the presence of air at 90 ⁰ C. (~ 115 ° C). The first azodiisobutyronitrile

65 additions are made in each case with a strong boil, the

B) Thereupon 1 part of maleic acid (2) will only be contained by very intensive cooling 111 parts of n-butanol, 111 parts of xylene and 0.05 part can. The resin obtained has an outflow time in Hydroquinone added and - under water - DIN cup 6, according to DIN 53 211, of 92.6 seconds.

109542/373

Example 5

Manufacture of stoving enamels
30 parts of the resins are mixed with 7.5 parts of titanium dioxide pigment rutile RN 56 and enough xylene that the mixture can be sprayed from a spray gun. This requires 12 parts of xylene for the resin according to Example 4, but 31 parts of xylene for the resin according to the comparative example. For painting practice, this means that with the paint made from the resin according to Example 4, with a single spray application, significantly greater paint layer thicknesses can be applied than with the paint made from the resin according to the comparative example. The specified mixtures are homogenized in a ball mill. Deep-drawn sheets are coated with both coatings (coating thickness of the coating: 60 μ). Some of the coatings are baked at some 15O ⁰ C and other at 180 ⁰ C at 13O ⁰ C. The stoving enamels have the following properties:

A- Deep drawing Behavior at burning capability sharp bending tempe- after around 80 ° C rature DIN ⁰ C 53156 Has paintwork Painting 130 0.6 min separate after thin cracks Has paintwork 150 9.4 mm separate thin cracks Painting 180 8.2 mm unchanged Painting Painting 130 0.2 mm flakes off according to ver Painting
flakes off
Painting same example 150 6.3 mm flakes off 180 4.9 mm

35

40

Claims (4)

Claim: Process for the production of copolymers which 1) a total of 0.9 to 1.2 moles of an N-2-oxaalkylamide acrylic and / or methacrylic acid with up to 9 carbon atoms in the oxaalkyl radical, 2) at least 0.001 mol of an α-ethylenically unsaturated, mono- or divalent carboxylic acid with up to 6 carbon atoms or mixtures thereof and / or an alkyl or oxaalkyl half esters of such a divalent carboxylic acid with up to 9 carbon material atoms in the alkyl or oxaalkyl radical or Mixtures of these half-esters, 3) an alkyl, oxaalkyl acrylate, alkyl, oxaalkyl methacrylate with up to 20 carbon atoms in the alkyl or oxaalkyl radical or mixtures of these esters, and / or styrene or Alkyl styrenes with up to 12 carbon atoms or mixtures thereof and optionally Additionally 4) another ethylenically unsaturated comonomer - with the amounts of the components under 1) to 4) in parts by weight 1) 5 to 45 parts, 2) 0.1 to 12.5 parts, 3) 20 to 90 parts and 4) make up no more than 30 parts - Contained in polymerized form by reacting acrylic or methacrylamide with paraformaldehyde and an alkanol or oxaalkanol and the monomers mentioned under 2) to 4) with polymer formation in the presence of customary aliphatic Azo compounds as polymerization initiators, characterized in that one A) in a first process stage ' a) 0.9 to 1.2MoI acrylic or methacrylic acid amide, b) 0.9 to 1.2 mol of paraformaldehyde (calculated as monomeric formaldehyde), c) at least 0.9 mol of an alkanol containing up to 8 carbon atoms or Oxaalkanols as well d) holds 0.001 to 0.5 mol of a tertiary, aliphatic monoamine containing up to 12 carbon atoms in an oxygen-containing atmosphere for a time of 15 to 120 minutes at a temperature of 50 to 100 ^° C., B) in a second process stage of the carboxylic acid and / or the half-ester (2) di & total amount or a partial amount, but at least 101 equivalent percent - based on the monoamine (d) - is added for a time of 1 to 24 hours at a temperature of 80 to 14O ⁰ C holds and C) in a third process stage - · if necessary - The remaining amount of the carboxylic acid and / or the half-ester (2), the ester and / or the styrene or alkylstyrene (3) and - optionally - The other comonomer (4) is added and in the presence of an aliphatic Azo compound copolymerized as a polymerization initiator.