DE2128681A1 - Stoving lacquer - based on aminoplast and a copolymer contg a sulphonium-salt - Google Patents

Abstract

Stoving lacquer contaions, as binder, a mixt. of (I) 3-60 wt. % of a usual aminoplast resin (opt. partly replaced by an epoxy and/or phenoplast resin and (II) 40-97% of a copolymer contg. (a) 8-97.5 wt. % of >=1 ester of an alpha, beta-olefinically unsatd. 3-5 C carboxylic acid with a 1-8 (oxa)alkanol, (b) 2-60% of >=1 hydroxyl-gp.-contg. comonomer, (c) 0.1-19% of >=1 3-5 C olefinically unsatd. carboxylic acid, (d) =55% of >=1 further olefinically unsatd. cpd. other than (a) to (c). Component (c) is a sulphonium salt of formula (I): where R is H or Me; R' and R" are indep. H, 1-4 C alkyl, 5-7 C cycloalkyl or 6-12C aryl; and X- is an anion of na (in)org. acid. Products are used in mfre. of water-dilutable stoving lacquers having relatively low soln. visc. contg. relatively little solvent when ready for sprng appln. so that covering and filling capacity are not adversely affected. (b) may be a sulphonium-salt of an oxalkylated S-vinylthioethane.

Description

67OO Ludwigshafen, June 8th, 1971 stoving enamels

The present invention relates to stoving enamels which are a mixture of a sulfonium-containing copolymer and optionally contain an aminoplast resin as a binder.

The following properties are particularly desirable for stoving enamels: Water-thinnable, good flow for both single-pigmented and metallic-effect paints and after stoving high hardness, high elasticity, weather resistance and resistance to cleaning agents and motor fuels. aside from that such lacquers must be perfectly processable: You may z. B. do not have too high a solution viscosity, it may be When processing paints from other origins at the same time in the same paint shop, no spray mist craters are formed, or when overburning, as can happen in the event of malfunctions can change the properties of the paintwork significantly.

The aim of the present invention is now to provide water-dilutable To produce stoving enamels with a relatively low solution viscosity, which in the ready-to-spray state contain as little solvent as possible, based on binder and pigment content, and thus not the disadvantageous effect on the filling power of the paintwork, as can be seen in conventional paints with high solution viscosity. Another goal of the present invention are paints, the laokings with a particularly advantageous combination of the metal, special metal strip coatings result in the desired properties.

The present invention relates to stoving enamels containing as a binder a mixture of I. 5 to 60 percent by weight of a conventional aminoplast resin, which can optionally be partially replaced by a conventional epoxy resin and / or phenoplast resin, and

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II. 40 to 97 percent by weight of a copolymer that

a) 8 to 97 * 5 percent by weight of at least one copolymerizable Esters of an ocß-olefinically unsaturated, 3 to Carboxylic acid containing 5 carbon atoms with alkanols or oxaalkanols containing 1 to 8 carbon atoms,

b) 2 to 60 percent by weight of at least one copolymerizable olefinically unsaturated hydroxyl group-containing Monomers,

c) 0.1 to 19 percent by weight of at least one copolymerizable olefinically unsaturated carboxylic acid with 3 to 5 Carbon atoms,

as well as, if applicable
^ d) up to 55 percent by weight at least one further below

a) to c) not mentioned copolymerizable olefinically unsaturated compound,

contains copolymerized, the sum of the percentages mentioned under a) to d) being 100, characterized in that the copolymer II as component (b) is a sulfonium salt the general formula

CH ₂ = C - S - CH ₂ - CH - OH CH ₂ R ₁

Φ _χ θ

CHR ₂ OH

contains polymerized, wherein
W R is hydrogen or a methyl group,

R, and R _{2 are} identical or different from one another and are hydrogen, an alkyl group with 1 to 4 carbon atoms, a cycloalkyl group with 5 to 7 carbon atoms or an aryl group with 6 to 12 carbon atoms, and Χ ^{θ denotes} an anion of an inorganic or organic acid.

A particularly advantageous embodiment of the invention Stoving enamels consist in that as component (b) in the copolymer II a sulfonium salt of an alkoxylated S-vinylthioethanol is polymerized »

The paints according to the invention containing sulfonium groups are due to their water compatibility and low solution viscosity

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would be particularly easy to process "They result in particularly strong paintwork, which is characterized by fuel resistance, even against so-called super fuels with a high aromatic content, high hardness, high elasticity and excellent weather resistance and alkali resistance »

Among the components that make up the stoving enamels according to the invention are constructed, the following is to be carried out in detail;

The binder according to the invention contains one as component (i) Usual aminoplast resin, some of which can optionally be replaced by a conventional epoxy or phenolic resin.

The usual condensation products are suitable as aminoplast resin of formaldehyde with amino compounds such as urea or melamine or piperazine, as such or etherified with alcohols having 1 to preferably 4 carbon atoms.

Aminoρlast precondensates are also suitable. The production of aminoplast condensates, as they are suitable for the binders according to the invention, are, for. B. described in Houben-Weyl, "Methods of Organic Chemistry" (1965) Volume 14/2, page 519 ff.

Suitable epoxy resins are the usual ones, such as. B. those obtained by condensation of bisphenol A with epichlorohydrin, with epoxy values from 0.02 to 0.5, preferably from 0.2 to 0.5. The production of such epoxy resins is z. B. described in the book by A. M. Paquin "Epoxydverbindungen und Epoxydharze" (Springer-Verlag 1958).

Suitable phenolic resins are the customary condensation products from formaldehyde and phenols, alkylphenols or polynuclear phenols, whose production z. B. in "Chemistry of Phenolic Resins" by K. Hultzsch, Kunststoffrundschau 7 (1960), pp. 435-440 will.

The proportion of the aminoplast resin or the mixture of the aminoplast resin with an epoxy or phenoplast resin in the binder of the

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Stoving enamels according to the invention is from 5 to 60, preferably 5 to 40 percent by weight of the total binder, an amount of 10 to 25 percent by weight is particularly preferred of the epoxy resin or phenoplast resin in component I can be up to 50 percent by weight »

The esters of acrylic acid or methacrylic acid with straight-chain or branched alkanols or oxa alcohols are particularly suitable as esters of an olefinically unsaturated carboxylic acid (a) containing 1 to 8 carbon atoms and containing 1 to 8 carbon atoms, polymerized into the copolymer (II) contain 1 to 8, preferably 1 to 4 carbon atoms in the alcohol radical, such as. B. acrylic or methacrylic acid esters of methanol, ethanol, i-propanol, n-butanol, i-butanol, tert ", -butanol, methyl glycol, ethyl glycol or 2-ethylhexanol, and mixtures of such esters, such as eg" B ₀ methyl methacrylate / n-butyl acrylate "Esters of cc, ß-olefinically unsaturated polycarboxylic acids, in particular dicarboxylic acids such as fumaric acid, maleic acid or itaconic acid, are also suitable,

The esters of o (, ß-olefinically unsaturated carboxylic acids are polymerized into the copolymer of the binder according to the invention in an amount of 8 to 97.5, preferably 50 to 88 percent by weight.

Component (b) of the copolymer (II) is according to the invention a sulfonium salt of the general formula

R.
ι

CH ₂ = C - S - CH ₂ - CH - OH

CHR ₂
OH

where R is hydrogen or a methyl group, R, and R _{2 are} identical or different to one another and are hydrogen, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms or an aryl group having 6 to 12 carbon atoms and

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Χ ^{θ means} an anion of an inorganic or organic acid.

Suitable compounds of this type are obtained, for example, by reacting HS-CH ₂ -CH ₂ -OH or HS-CH ₂ -CH-OH or HS-CH ₂ -CH-OH

in, (

with acetylene or methylacetylene at temperatures of about 50 to 100 ⁰ C in the presence of basic catalysts under nitrogen as protective gas, the corresponding vinyl or »Isopropenylthioäther are obtained, which are then either directly polymerized and then by reacting with alkene, cycloalkene and / or aralkene oxides are converted into the sulfonium salts in the presence of organic or inorganic acids or converted into the corresponding vinyl or isopropenylsulfonium salts by alkylation with these alkene oxides in the presence of Η-active substances, preferably organic or inorganic acids, before the polymerization. Suitable aralkene, cycloalkene and alkene oxides are ζ. Β »styrene oxide, cyclohexene oxide and preferably propylene oxide and ethylene oxide.

Suitable the anions Χ ^θ forming Η-active substances are preferably inorganic and organic acids, such as. B. phosphoric acid, phosphorous acid, boric acid, formic acid, acetic acid, acrylic acid, stearic acid and oleic acid »Preferably suitable as component (b) are the sulfonium salts of oxyalkylated, especially oxyethylated S-vinylthioethanol.

The copolymerizable olefinically unsaturated hydroxyl group-containing Component (b) is present in the copolymer (II) contained in the binder in an amount of 2 to 6o, preferably 5 to 40 percent by weight polymerized "

As copolymerizable olefinically unsaturated carboxylic acids with 3 to 5 carbon atoms (c) are particularly suitable for acrylic acid and methacrylic acid. Also suitable are, for example, olefinically unsaturated dicarboxylic acids, such as maleic acid, fumaric acid or Itaconic acid, its anhydrides and half esters with alcohols with 1 to 8 carbon atoms.

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The component (c) is in an amount of. 0.1 to 19, preferably 0.5 to 10 and in particular 1.5 to 6 percent by weight im Copolymer (II) incorporated into the polymer.

In addition to the monomers mentioned under a) to c), up to 55 percent by weight of at least one further copolymerizable monomer (d) not mentioned under a) to c) can be polymerized into the copolymer (II). Such suitable monomers include vinyl compounds such as vinyl aromatics, for "example, styrene, oc -Met hy! Styrene, o-, m- and ρ-methyls Tyrol, dichlorostyrene, Vinylester of straight-chain or branched carboxylic acids having 2 to 11 carbon atoms, such "B. vinyl acetate, vinyl propionate or vinyl pivalate, vinyl amides, such as. B-N-Viny! Pyrrolidone, vinyl alkyl ethers with Γ to 8 carbon atoms in the alkyl group, such as Zo B “vinyl butyl ether and derivatives of copolymerizable #, ß-olefinically unsaturated carboxylic acids, such as. B. acrylonitrile, methacrylonitrile, acrylamide or methacrylamide »

In addition, oCβ-olefinically unsaturated components are used as component (d) Carboxylic acid esters suitable which, in addition to the polymerizable olefinic grouping, have further functional groups, for example Contain hydroxyl groups or basic groups, such as the monoesters of acrylic acid or methacrylic acid with polyvalent, in particular dihydric alcohols or alcohols having 2 to 8 carbon atoms, such as, for example, ethylene glycol monoacrylate, butanediol monoacrylate or Ν, Ν-DialkylaminoalkylacryIatB or N, N-Dialkylaminoalkylmethacrylate the general formula

R °
¹ ^ NXOC-CR = CH ₀

^R 2.

wherein R is hydrogen or a methyl group, R, and Rp are the same or different and are an alkyl radical having 1 to 4 carbon atoms, and X represents an alkylene group preferably having 2 carbon atoms, such as "B. Diäthy aminoäthylmethacrylat and N, N-dimethylaminoethyl _e!

In addition: in special cases, copolymerizable ones are suitable Compounds with multiple double bonds, such as. B, butadiene,

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Styrene and mixtures of styrene and at least one of the others mentioned under (d) are particularly suitable as component (d) Monomers. Styrene can be used in amounts of up to 55 * preferably be polymerized into the copolymer (II) in amounts of 20 to 50 percent by weight.

A corresponding selection according to the type and amount of the copolymer (II) polymerized monomers enable the person skilled in the art to determine the properties of the paint and the paintwork in each case To suit your needs.

As an example of a preferred embodiment, this includes Copolymer (II) of the binder according to the invention 35 bis 45 percent by weight of n-butyl acrylate or a mixture of n-butyl acrylate and methyl methacrylate as component (a), 6 to 40 percent by weight a sulfonium salt of oxethylated S-vinylthioethanol as component (b), 1.5 to 6, preferably 2 to 4 percent by weight Acrylic acid or methacrylic acid as component (c) and 20 to 50 percent by weight of styrene are copolymerized.

The binders according to the invention can also contain other binders customary for baking enamels in minor amounts, such as modified natural resins, such as B. cellulose esters or cellulose ethers, polyacrylates, alkyd resins and maleinized oils.

In addition to the binder components, the paints according to the invention can be used other auxiliaries, such as soluble dyes, curing catalysts, solvents, agents for improvement the course, customary inorganic pigments such. B. titanium dioxide, organic pigments, such as. B. phthalocyanine dyes, as well as other auxiliaries customary for paints.

The paints can be produced in the customary manner by mixing the components or component mixtures in customary mixing units take place. In most cases it is useful if the binder mixture of the paints is 20 to 80, in particular 30 to 00 percent by weight, based on the total weight of the directly processable stoving enamel.

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The lacquers are suitable for producing lacquers on wood, paper, ceramic material and plastics »

The paints according to the invention have proven to be particularly advantageous for metal painting "

The application of the lacquer to the objects to be lacquered can be done by the usual methods, for example by spraying on, brushing on, Pouring on, rolling on, flooding, dipping or soaking,

The stoving of the paintwork is generally carried out at temperatures from 40 to 180 ° C, in particular 120 to 150 ° C, and - depending from the temperature - within 10 to 120, in particular 20 to 60 minutes in the usual devices suitable for this purpose carried out"

As can be seen from the examples and comparative examples given below, the paints according to the invention are distinguished by the particularly advantageous property of being water-thinnable compared to commercially available externally crosslinking stoving paints, such as those described in the above-mentioned patents. _{Compared to similarly structured paints which contain polymerized monomers a} such as s «B = ethylene glycol or butanediol monoacrylate in the mixed polymer component (II) instead of the sulfonic acid monomers a, the paints according to the invention have significantly higher filling power, and those from it obtained coatings, in addition to the advantages already mentioned above, a significantly improved resistance to so-called super fuels with a high aromatic content, as is particularly desirable for metal paints, and excellent stain resistance, such as. B, against ink, shoe polish or lipstick, on,

The resistance to fuel can be shown very well by a simple test. This is on the branded Painting a cotton ball soaked with xylene placed and covered = After 15 minutes of exposure, the cotton ball will be removed "Two hours later, no changes to the Painting at the relevant point, such as ζ Β change of color, increased sensitivity to scratching and blistering

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The parts and percentages given in the examples are parts and percentages by weight »

example 1

In one with stirrer, reflux condenser, feed vessel and heating device provided glass flask are presented 50 parts of a mixture consisting of 30 parts of methyl methacrylate, 28 parts of n-butyl acrylate, 25 parts of styrene, 45 parts of oxethylated vinylthioethanol with acetic acid as the counterion, 2 parts of acrylic acid, 1.5 parts of azodiisobutyronitrile, 50 parts of xylene and 50 parts n-butanol consists of »

The initial charge is heated to reflux temperature (117 ° C.) while stirring and passing nitrogen over it has started, the feed of the remainder of the mixture is started. The feed ends in 90 minutes, 1st hour after At the end of the feed, a further 0.1 part of azodiisobutyronitrile is added and the polymerization is carried out for 3 hours at reflux temperature continued.

21 parts of the resulting polymer solution are homogenized with 9 parts of the 50 # strength butanolic solution of a customary butanol-etherified piperazine / formaldehyde condensation product, 30 parts of xylene and 7.5 parts of titanium dioxide pigment in a ball mill for 24 hours. The paint color formed is applied by means of a spray gun to unprimed thermoforming sheets, short and baked 30 minutes at 130 ⁰ C »The resulting high-gloss white paint at a thickness of 50 μ, a pendulum hardness according to DIN 53 157 of 143 and a Elasizität according to DIN 53156 from 6.5 ", the paint is very good weather-resistant. It is not attacked by super motor fuels and by most aromatic solvents (eg xylene) »The paintwork is scratch-resistant and does not show any cracks when bent sharply»

Example 2

Analogous to the manufacturing instructions for the polymer solution in

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Example 1 is a 50 # solution of a copolymer 15 parts of methyl methacrylate, 50 parts of n-butyl acrylate, 35 parts Styrene, 35 parts of oxethylated vinylthioethanol with formic acid as a counterion and 2 parts of acrylic acid in a solvent mixture of equal parts of n-butanol and xylene using 0.5 parts of methylbutenol prepared as a regulator. The expiry time the 50 # solution according to 6 DIN 53 211 is 15 seconds, after 4 DIN 53 211 52 seconds.

The polymer solution is mixed with a commercially available melamine / formaldehyde condensate in the same quantitative ratio as in Example 1 mixed »

Check for filling power

To dilute 100 g of this mixture to spray viscosity, d. H. to an outlet viscosity according to 4 DIN 53 211 of 18 seconds, 39 g of xylene are required., With a commercially available polymer, which was mixed analogously with the same melamine-formaldehyde condensate and intended for the same purpose is, to achieve the same outlet viscosity per 100 g of 50 # polymer solution, 70 g of xylene are required »This means that with a paint made from the commercially available polymer to achieve a certain paint film thickness, significantly more color must be applied, and that much more solvent must evaporate from the paint film than in the case of a paint made from the copolymer according to the invention according to the present example was produced.

Example 3

Manufacture and testing of a paint job?

21 parts of the polymer solution according to Example 2 are 4.7 parts the 50 # strength butanolic solution of a conventional one with butanol etherified piperazine / formaldehyde condensation product, 6 parts of xylene and 7.5 parts of titanium dioxide pigment in a ball mill for 24 hours homogenized. The paint that is formed is applied to unprimed deep-drawn metal sheets using a spray gun, for 2 minutes flashed off for a long time and baked for 30 minutes at 120 ° C., The paintwork obtained has the following properties?

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Pendulum hardness according to DIN 53 157s, elasticity according to DIN 53 156s Behavior when bending sharply;

Salt spray test according to DINs

Testing in the Kesternich device according to DIN 50 0l8s

No significant corrosion damage.

95 seconds
6.5

perfect, no cracks, no flaking

1.5 mm rusting under after 250 hours, practically hardly any Loss of gloss

weak drop in gloss

Grinding grooves on the metallic substrate, made with An emery paper (180 grit) are already applied by spraying once on vertical surfaces completely covered (spraying was carried out in manual mode with an air pressure of 5j5 atmospheres on a vertical surface) »

Example 4

(with comparison tests)

There were polyacrylic ester copolymers using various Hydroxyl group-containing monomers produced, all 50 # ig with xylene as .solvent and of about the same solution viscosity. Using these acrylic ester copolymers stove enamels were produced according to the following recipe:

30 parts by weight of pigment paste, consisting of 48 parts of cadmium red pigment, 44 parts of the 50% butanolic solution of a butylated melamine-formaldehyde resin and 8 parts of xylene, are mixed with 50 parts of the 50% acrylic resin solution, 5.6 parts of the above-mentioned melamine resin, 8 , 6 parts of xylene and 5 parts of an aromatic mixture having a boiling range to 15O ⁰ C mixed. If necessary, enough xylene is added that the flow viscosity according to 4 DIN 53 211 is 18 seconds.

The lacquer is then sprayed in three cross passageways, each having 1 minute Between venting the air for 5 minutes on thermoforming sheet 50 minutes baked at 120 ⁰ C for.

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Result;

Lacquer contains as an acrylic ester copolymer

Changes observed on paintwork after xylene test? immediately? after 2 hours

As 15 methyl methacrylate 53 n-butyl acrylate 15 styrene 15 butanediol monoacrylate 2 acrylic acid

Bs 15 methyl acrylate 53 n-butyl acrylate 15 styrene 15 ethylene glycol monoacrylate 2 acrylic acid

C; 15 methyl methacrylate 53 n-butyl acrylate 15 styrene 15 vinylthioethanol, oxethylated

with H, PCL · acrylic acid as counterion 2

Ds 25 methyl methacrylate 43 n-butyl acrylate 15 styrene 15 butanediol monoacrylate 2 acrylic acid

It 25 methyl methacrylate 43 n-butyl acrylate 15 styrene 15 vinylthioethanol, oxethylated

with H ^ PCk as counterion 2 acrylic acid

soft, discolored, difference in gloss

soft, gloss difference

hard, hardly any difference in gloss

soft, gloss change

hard, hardly any change in gloss

hard, discolored

hard,

Gloss difference

unchanged

Gloss change

unchanged

Example 5

20 parts of the 60 # aqueous solution of a copolymer containing 30 percent by weight styrene, 30 percent by weight n-butyl acrylate, 40 percent by weight vinylthioethanol, oxethylated with formic acid as the counterion, and 10 parts of a 30 # aqueous solution of a melamine-formaldehyde condensation product are after Addition of 7.5 parts of titanium dioxide pigment (rutile) rubbed on a ball mill for 24 hours »The weight ratio of the binders is 80 s 20 (lacquer l)"

In exactly the same way, a varnish is made from a coconut alkyd resin and a melamine-formaldehyde resin with the binding agent

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medium ratio 8o s 20 (paint II).

By spraying onto deep-drawn metal sheets, coatings are obtained which ^{are baked for 30 minutes at 120 °} C. and 24 hours at 150 ^° C. (aging test). The following results were obtained?

Burn-in shine Erich pendulum scratch 10 # conditions (black hardness solid-vinegar-soda-soda glass = value acid lye lye. 100 %) + \ + \ boiling

: L ι st d.

Lacquer I

120 °
30 ' Hours, 60 7, 2 144 " Yes 150 °
24 II 60 3, 5 152 " Yes paint

120 °
30 '51 2.9 52 "yes 0 0 0

150 °
24 hours, 43 1.7 97 "yes

⁺ ) Duration of action 12 hours at 20 ^° C

+ = constant
0 = inconsistent

Example 6

Exactly analogously to Example 5, lacquers are produced from a Triple combination of mixed polymer II, melamine resin and an epoxy resin (polymeric 2,2-bis- | 4-hydroxyphenyl-propane-glycidether with an epoxy value of approx. 0.2) in the weight ratio 75 ϊ 25 ϊ 10 (lacquer A) \ md from the combination of coconut alkyl resin / Melamine resin / epoxy resin 75; .25 s 10 (lacquer B).

Coatings produced therefrom are baked ^{at 150 ° C. for 1/2 hour.} As a comparison, a coating was tested which, as a binder, was a combination of a self-crosslinking acrylate resin containing methylolather groups and an epoxy resin in a ratio of 9; 1 contained as a binder (lacquer C),

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The painted parts were in the oily aqueous solution of a Commercial detergent boiled (test for suitability as washing machine paint).

Lacquer A was stable for 5 days without change in this test, Lacquer B was stable for a few hours and lacquer C was stable for 6 days without any noticeable change.

Example 7

A copolymer containing 30 parts of styrene, 30 parts of n-butyl acrylate and 40 parts of oxyethylated S-vinylthioethanol with acrylic acid as the counterion, prepared by oxyethylating the copolymer of styrene, n-butyl acrylate + CH ₂ = CH-S with acrylic acid as the counterion.

CH ₂

OH

ion 60% in isopropanol, 40 parts of a 30% aqueous solution of a urea / formaldehyde adduct are added, 10 parts of titanium dioxide are rubbed in, painted on wood and ^{crosslinked at 110 °} C. within 30 minutes Tempered and waterproof, that is, when exposed to water at room temperature within 24 hours, no swelling of the film is observed.

Example 8

Are 30 parts of styrene, 20 parts of methyl acrylate, 20 parts

Acrylic acid and 30 parts ι 3

CH ₂ -CH-S-CH ₂ -CH-OH

eopolymerisiert at 115 ° C within 5 hours by means of 1.5 parts of azodiisobutyronitrile, adjusted with isopropanol to a solids content of 50 weight percent and then oxpropyliert with 18.5 parts of propylene oxide at 30 ⁰ C, a solution with 20 parts produced a 50 ^ aqueous urea / formaldehyde solution can be diluted and results in spread than 100 μ film on paper after drying for 1 hour at 100 ⁰ C a good water-resistant impregnation of the paper.

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Claims (2)

Claims 1 “Stoving enamels, containing a mixture of I ₀ 3 to 6o percent by weight of a conventional aminoplast resin, which can optionally be partially replaced by a conventional epoxy resin and / or phenoplast resin, and II. 40 to 97 percent by weight of a copolymer that a) 8 to 97.5 percent by weight of at least one copolymerizable Esters of an ocß-olefinically unsaturated 3 to 5 carbon atoms containing carboxylic acid with 1 to 8 carbon atoms containing alkanols or Oxaalkanols, b) 2 to 60 percent by weight of at least one copolymerizable olefinically unsaturated hydroxyl group-containing Monomers, c) 0.1 to 19 percent by weight of at least one copolymerizable olefinically unsaturated carboxylic acid with 3 to 5 carbon atoms, as well as, if applicable d) up to 55 percent by weight of at least one additional under a) to c) not mentioned copolymerizable olefinically unsaturated compound, contains in copolymerized form, the sum of the percentages mentioned under a) to d) being 100, characterized in that the copolymer II as component (b) is a sulfonium salt of the general formula CH ₂ = CS-CH ₂ -CH-OH * Χ ^θ CH ₀ R ₁ t ei 1 CHR ₂
OH contains polymerized, wherein
R is hydrogen or a methyl group, R, and Rp are identical or different and are hydrogen, an alkyl group with 1 to 4 carbon atoms, a cycloalkyl group with 5 to 7 carbon atoms or an aryl group with 6 to 12 carbon atoms and X is an anion of an inorganic or organic acid means ^r > ?. / 088 1 - ^Hl - 2. Stoving enamels according to Claim 1, characterized in that the copolymer II contains, as component (b), a sulfonium salt of an alkoxylated S-vinylthioethanol in polymerized form " Badische Anilin- & Soda-Fabrik AG 2 Q 9 «'■ V / 0 8 8 1