EP0342205A1

EP0342205A1 - Hardenable composition on the basis of a michael addition product, process for the manufacture thereof and use thereof

Info

Publication number: EP0342205A1
Application number: EP88902842A
Authority: EP
Inventors: Werner Alfons Jung
Original assignee: BASF Lacke und Farben AG
Current assignee: BASF Farben und Fasern AG
Priority date: 1987-03-28
Filing date: 1988-03-25
Publication date: 1989-11-23
Also published as: AU616886B2; BR8807437A; CA1338911C; ES2023455B3; ATE64400T1; WO1988007556A1; EP0287842B1; DE3863224D1; JPH0762047B2; ZA882144B; AU1542588A; DE3710431A1; EP0287842A1; JPH02500282A

Abstract

A hardenable composition contains as components A) compounds with at least two activated double bonds (I), which are alpha , beta -unsaturated carbonyl compounds, alpha , beta -unsaturated carboxylic acid esters or alpha , beta -unsaturated nitrile groups, and as components B) compounds containing at least two active hydrogen atoms or at least two groups with active hydrogen atoms or at least one active hydrogen atom and at least one group with an active hydrogen atom, and ordinary additives, catalysts, if necessary pigments and an organic solvent. Components A) or components B) or components A) and B) are based on a branched soluble acrylate copolymer (P) obtained by polymerization of a) 3 to 30 wt.% of monomers with at least two ethylenically unsaturated polymerizable double bonds, b) 5 to 60 wt.% of monomers with functional groups and c) 5 to 92 wt.% of other ethylenically unsaturated monomers where the sum of a), b) and c) is equal to 100 wt.%. The invention also relates to the process for manufacturing the hardenable composition.

Description

Curable composition based on a Michael additive.

Product, process for its manufacture and its use

The invention relates to a curable composition, containing as component A) compounds with at least two activated double bonds (I), which are ^, fi-unsaturated carbonyl compounds, a. , (?, - unsaturated carboxylic acid esters or π, p, -unsaturated nitriles, and compounds B), which contain at least two active hydrogen atoms or at least two groups with active hydrogen atoms or at least one active hydrogen atom and at least one group with an active hydrogen atom, and conventional additives, catalysts, optionally pigments and organic solvents.

From DE-OS 35 08 399 compositions are known which are obtained by reacting compounds with at least two activated double bonds (I) with compounds containing active hydrogen atoms. These compositions react under the influence of bases to form a Michael addition product. The Michael acceptor component can be derived, for example, from acrylate resins containing hydroxyl groups, epoxy resins, oligomeric polyols or oligomeric polyamines. The Michael donor component can, for example, be derived from polyols, polyamines or polymercaptans. The binders described in DE-OS 35 08 399 can be used as two-component systems for coatings. They pre-harden under catalysis. Bases easily at room temperature and at elevated temperatures. The advantages of the systems described exist in that they do not require free isocyanates for curing. However, the known systems are disadvantageous in terms of solvent resistance, chemical resistance and elasticity of the coatings obtained from them,

From US Pat. No. 4,408,018 Michael addition products are known from acrylate polymers with acetoacetate groups and polyacrylate crosslinking agents with double bonds activated for Michael addition. The systems known from US Pat. No. 4,408,018 also lead to coatings with disadvantageous properties with regard to solvent resistance, chemical resistance and elasticity.

EP-A-158 161 describes coating compositions which harden at low temperatures and are based on branched acrylate copolymers containing hydroxyl groups and melamine-formaldehyde resins or polyisocyanates as crosslinking agents. In the polymerization for the preparation of the acrylate copolymer 3 to 25 wt .-% of monomers are polymerizable with at least two olefinically ungesättig¬ ^'double bonds th used. The coating compositions based on the systems described have good gasoline resistance and good resistance to long-term exposure to water or water vapor. However, the melamine-formaldehyde resins or polyisocyanates used as crosslinkers have a disadvantage for toxicological reasons.

The object of the present invention was to provide coating compositions which can cure at low temperatures, therefore can preferably be used in automotive refinishing, are largely free of isocyanate and have improved properties compared with the systems from DE-OS 35 08 399 in relation have solvent resistance, chemical resistance and elasticity.

According to the invention, this problem is solved by the curable composition of the type mentioned at the outset, that either component A) or component B) or components A) and B) are based on a branched soluble acrylate copolymer (P) which can be obtained by copolymerizing

a) 3 to 30% by weight of monomers with at least two ethylenically unsaturated polymerizable double bonds,

b) 5 to 60 wt .-% monomers with a functional group and

c) 5 to 92% by weight of other ethylenically unsaturated monomers,

the sum of a), b) and c) being 100% by weight.

The compounds A) are compounds which contain activated olefinically unsaturated groups and can serve as a Michael acceptor. Compounds of component B) form carbanions under the influence of suitable catalysts, which are added to the activated double bonds of component A). The compounds of component B) are Michael donors. According to the invention, at least one of components A) and B) should be based on a branched, soluble acrylate copolymer (P), i.e. be available from this. According to the invention, component A) can therefore be obtainable by reacting the branched, soluble acrylate copolymer (P) with a compound (1) which contains at least one activated double bond (I).

It is also possible for component B) to be obtainable by reacting the branched soluble acrylate copolymer (P) with a compound (2) which, in addition to a group which is reactive with the acrylate copolymer (P), has at least one active hydrogen atom or at least one group contains an active hydrogen atom. The soluble branched acrylate copolymer (P) is therefore used in accordance with the invention as a precursor for the compounds A) and / or B). The branched acrylate copolymer can be obtained by copolymerization of 3 to 30% by weight, based on the total weight of the monomers, of monomers having at least two ethylenically unsaturated double bonds. •

Compounds of the general formula can advantageously be used as component a)

R 0 0 R

CH i. = CCX- (CH ₉ ) nXCC = CH ά

With

R = H or CH ₃

X = 0, NR ', S with R ¹ = H, alkyl, aryl n = 2 to 8 can be used.

Examples of such compounds are hexanediol diacrylate, hexanediol dimethacrylate, glycol diacrylate, glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate. Divinylbenzene, suitable as component a). Mixtures of multifunctional monomers can of course also be used.

Component a) can also be a reaction product of a carboxylic acid with a polymerizable, olefinically unsaturated double bond and glycidyl acrylate and / or glycidyl methacrylate. Component a) can furthermore be a polycarboxylic acid or unsaturated mononecarboxylic acid esterified with an unsaturated alcohol containing a polymerizable double bond. As component a), reaction products of a polyisocyanate with unsaturated, polymerizable double bonds containing alcohols or amines are advantageously used. An example of this is the reaction product of one mole of hexamethylene diisocyanate and two moles of allyl alcohol. .

Another advantageous component a) is a diester of polyethylene glycol and / or polypropylene glycol with an average molecular weight of less than 1500, preferably less than 1000, and acrylic acid and / or methacrylic acid.

Monomers with a functional group are used as component b), the selection of this functional group being based on the type of compounds (1) and (2); by reacting the soluble branched acrylate copolymers with the compound (1) or (2), the compounds (A) and (B) are obtained. The monomers b) which can be used according to the invention will be discussed at a later point.

The further polymerizable monomers ^' of component c) can advantageously be selected from the group styrene, vinyl toluene, alkyl esters of acrylic acid and methacrylic acid, alkoxyethyl acrylates and aryloxyethyl acrylates and the corresponding methacrylates, esters of maleic and fumaric acid. Other examples which may be mentioned are methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isopropyl acrylate, isobutyl acrylate, pentyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate,

3,5,5-trimethylhexyl acrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, octadecyl acrylate, octadecenyl acrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethyl butyl methacrylate, octyl methacrylate, 3,5,5-trimethyl hexyl methacyl acrylate, octyl methacrylate, octyl methacrylate, Butoxyethyl acrylate, butoxyethyl methacrylate, methyl methacrylate, ethyl methacrylate, Propyl methacrylate, isopropyl methacrylate, butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride and phenoxyethyl acrylate. Further monomers can be used, provided they do not lead to undesirable properties of the copolymer. The selection of component c) depends largely on the desired properties of the acrylate copolymer in relation to elasticity, hardness, compatibility and polarity. These properties can be controlled in part using the known glass transition temperatures of the monomers.

Component b) of the acrylate copolymer can advantageously be a hydroxyl-containing ethylenically unsaturated monomer. Examples of these are hydroxyalkyl esters of acrylic acid and / or methacrylic acid with a primary hydroxyl group. Component b) can also be at least partially a reaction product of one mole of hydroxyethyl acrylate and / or hydroxyethyl methacrylate and an average of two moles of caprolactone. However, hydroxyl group-containing esters of acrylic acid and / or methacrylic acid with a secondary hydroxyl group can also be used as monomers containing hydroxyl groups. Advantageously, these are reaction products of acrylic acid and / or methacrylic acid with the glycidyl ester of a carboxylic acid with a tertiary carbon atom. Examples of hydroxyl-containing ethylenically unsaturated monomers are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyamylacrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate and the corresponding methacrylates. Examples of OH monomers with a secondary OH group are 2-hydroxypropyl acrylate, 2-hydroxibutyl acrylate, 3-hydroxibutyl acrylate and the corresponding methacrylates.

Compositions according to the invention are advantageous in which component A) is based on a soluble crosslinked acrylate copolymer, component b) the Acrylatcopoly erisats a hydroxyl group-containing

Is monomer, and compound (1) is a monoester σ, j3-unsaturated carboxylic acids. In this case, the branched, hydroxyl-containing copolymer is reacted with monoesters <. ^ - unsaturated carboxylic acids in a transesterification reaction so that a branched polyacrylate with free olefinically unsaturated double bonds is obtained. The compound A obtained ) can then be combined with the compounds B) to form a Michael addition product. Advantageously, in this case, as compound (1) esters of & (^ - unsaturated carboxylic acids in questions whose ester groups have no more than 4 to 6 carbon atoms, such as, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isopropyl acrylate, isobutyl acrylate, pentyl acrylate, the corresponding methacrylates and the corresponding esters of fumaric acid, maleic acid, crotonic acid, dimethylacrylic acid. the compounds (1) are reacted in known transesterification reactions with the OH groups of the branched acrylate copolymer (P). ^'

The following are other manufacturing methods for the

Component A) described:

Component A) is advantageously based on a soluble pre-crosslinked acrylate copolymer (P), the

Component b) is a monomer containing hydroxyl groups, and the hydroxyl-containing acrylate copolymer is reacted with a ", ^> - unsaturated carboxylic acid (compound (1)). In this case, component A) is obtained by esterification of a hydroxyl-containing branched acrylate copolymer with an unsaturated carboxylic acid.

Furthermore, component A) can advantageously be prepared by reacting the above-described hydroxyl-containing acrylate copolymer (P) with a compound which, in addition to group (I), contains an isocyanate group. The reaction between this connection (1) and the branched acrylate copolymer takes place in this case with the formation of a urethane bond. Compound (1), which contains an isocyanate function in addition to group (I), is advantageously an isocyanatoalkyl ester of an unsaturated carboxylic acid of the general type

Formula 'R 0 ι if CH ₂ = CCOX-NCO,

where R = H, CH ₃ , C ₂ Hg and X = (CH ₂ ) _n with n = 1-12; but it can also be m-isopropenyl-ιx, c -dimethylbenzyl isocyanate or selected from the group of reaction products of diisocyanates with OH, NH, SH or COOH-functional derivatives of acrylic acid, methacrylic acid, fumaric acid, maleic acid, crotonic acid and dimethylacrylic acid.

Advantageously, for the production of component A) the branched hydroxyl group-containing acrylate copolymer is reacted with a compound (1) which is an amide of alkoxy-methyl groups of a <^, (^ - unsaturated carboxylic acid or the general formula

R 0 R ¹ l II I p

CH ₂ = CCNX-COOR corresponds, with R = H, CH ₃

R ¹ = H, alkyl, aryl R ^ = alkyl - - - -

X = -C-, -CH-, -CH-, -CH- II 11 ι 1 I 0 R OR C00R

Examples of such compounds are methoxymethyl acrylamide, methoxymethyl methacrylamide, butoxymethylacrylamide, butoxymethyl methacrylamide, isobutoxymethylacrylamide, isobutoximethyl methacrylamide, analogous ide of fumaric acid, crotonic acid and dimethylacryl acid, glycolic acid methyl amide, such as methyl acrylate, such as kolatbutylether, methyl acrylamidoglycolate and butylacrylamidoglycolate.

Component A), which is based on a branched, soluble acrylate copolymer and contains at least two activated double bonds, can also be prepared by reacting an acrylate copolymer containing epoxy groups and a compound (1) which contains a carboxyl or amino group. In this case, a monomer containing epoxide groups, such as e.g. Glycidyl esters of unsaturated carboxylic acids or glycidyl ethers of unsaturated compounds are used. Examples of component b) include: glycidyl acrylate, glycidyl methacrylate, glycidyl ester

₁₅ of maleic and fumaric acid, glycidyl vinyl phthalate, glycidyl allyl phthalate, glycidyl allyl alonate. The epoxy groups of the acrylate copolymer are then reacted with the carboxyl or amino groups of the compound (1). The compound (1) is advantageously selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, dimethylacrylic acid, fumaric acid monomethyl ester, reaction products of carboxylic acid anhydrides and hydroxyalkyl esters =. ^ - unsaturated acids, such as adducts of hexahydrophthalic anhydride, phthalic anhydride, phthalic anhydride

25 maleic anhydride and hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate. The compound (1) can furthermore be t-butylaminoethyl (meth) acrylate, bisacrylaidioacetic acid or bis (acrylamidoethyamin). Particularly preferred are compounds with several acti¬

30 fourth double bonds used, e.g. Bisacrylamido¬ acetic acid.

The branched soluble acrylate copolymer (P) can function as a functional monomer b) monomers with ester functions __. contain. The esterification alcohol should advantageously not contain more than 6 carbon atoms. To produce component A), the acrylate copolymer prepared in this way is reacted with a compound (1) which in addition to group (I) has an OH, NH or SH group. Possible components b) are alkyl esters of acrylic acid, methacrylic acid, crotonic acid, maleic and fumaric acid, such as, for example, the corresponding methyl, ethyl, propyl, isopropyl, butyl, isobutyl and pentyl esters. Longer-chain alcohol residues in the ester group are less favorable because their transesterification and distillation after the transesterification requires excessively high temperatures. Amino alkyl esters of the mentioned <, -unsaturated carboxylic acids are also suitable. Component A) is then obtained by transesterification or transamidation reactions. These reactions are known to the person skilled in the art and require no further explanation.

5 Branched acrylate copolymers containing isocyanate groups can also be used to prepare component A). In this case, monomers containing NCO groups are used as monomer b). The acrylate copolymer having isocyanate groups is then reacted with _Q compounds (1), which in addition to the group (I) OH, NH, SH or COOH groups. In this case, the monomers b) can be selected from the group of vinyl isocyanates, such as, for example, vinyl isocyanate and m-isopropenyl -σt., C <.- dimethylbenzyl isocyanate, isocyanato alkyl ester 5 cA, (i-unsaturated carboxylic acids of the general formula

R 0

I II

CH ₂ = CC-0-X-NC0, where R = H, CH ₃ , C ₂ H ₅ 0 and X = (CH ₂ ) with n = 1-12

mean.

Adducts of, for example, = isophorone diisocyanate with hydroxyalkyl (meth) acrylates, such as, for example, hydroxyethyl methacrylate, can also be used as component b). For the addition it is advantageous to select those compounds which, in addition to the OH, NH, SH or COOH group, have two or more 1 more structural elements (I) included. In this way, two or more double bonds of type (I) are introduced with an addition step. This is advantageous because the addition of hydroxyl groups to isocyanate groups

5 urethane or urea groups are formed, which generally greatly increase the viscosity of the binders, which is not always desirable. Examples of this are the reaction products of acrylic acid or methacrylic acid or another o, (-ethylenically 10 unsaturated carboxylic acid and glycidyl acrylate or glycidyl methacrylate. This reaction produces a free hydroxyl group which then attaches to the NCO groups of the acrylate copolymer lymerisats is added.

For the preparation of the acrylate copolymer, the monomer component b) can advantageously contain an alkoxymethyl group-containing amide of a -, unsaturated carboxylic acid or a compound of the general formula

R 0 R ¹ ^A CH ₂ = CCNX-COOR

with R = H, CH ₃

R ¹ = H, alkyl, aryl

25

R ² = alkyl

X = -C-, -CH-, -CH-, -CH-

«1 1 ¹ 1

0 R ** C00R

In this case, compounds are used as compound (1) which, in addition to group (I), contain OH, NH or SH groups. Examples of the monomers b) are N-alkoxymethyl (meth) acrylamides, such as methoxymethylacrylamide, methoxymethylmethacrylamide, isobutoxymethylacrylamide,

35 isobutoxymethyl methacrylarnio and isobutoxymethyl ethacrylamide. The alkoxy (eth) crylamidoglycol alkyl ethers are also suitable. Of course, component b), which as

Michael donor serves and has active hydrogen atoms, based on the soluble branched acrylate copolymer. Some production methods for component B), which is obtained from an acrylate copolymer having a functional group and the compound (2), are shown below.

The soluble branched acrylate copolymer preferably contains hydroxyl groups which react in a subsequent reaction with the compounds (2). In addition to the active hydrogen atom or the group with active hydrogen atoms, the compounds (2) contain an ester or acid group. In this case, the monomers b) are preferably selected from the group of the hydroxyalkyl esters, J-unsaturated carboxylic acids. The compounds (2) are preferably selected from the group of acetoacetic acid, cyanoacetic acid, malonic acid, cyclopentanone carboxylic acid, cyclohexanone carboxylic acid and the respective alkyl ester.

The monomers b) can also be monomers with glycidyl groups. In this case, the branched acrylate copolymer containing epoxy groups is reacted with (2), these compounds having carboxyl or amino groups in addition to group (I). Monomers with glycidyl groups have already been mentioned. Suitable compounds (2) are acetoacetic acid, cyanoacetic acid, malonic acid, cyclopentanone carboxylic acid, cyclohexanone carboxylic acid. Component B) is preferably obtained by reacting an acrylate copolymer containing carboxyl groups with compounds (2), the reaction products of a polyepoxide with n mol of epoxy groups and (n-1) mol of a compound with carboxyl or amino-carboxyl or amino groups and the like Represent group with active hydrogen. An example of this is the reaction product of one mole of trimethylolpropane triglycidyl ether and two moles of cyanoacetic acid or two moles of acetoacetic acid. In this case, the monomer component b) Ethylene-unsaturated monomers containing carboxyl groups, for example acrylic acid or methacrylic acid, are used.

A curable composition in which the soluble branched acrylate copolymer is obtainable by copolymerization of is particularly preferred

a) fertilize 3 to 30% by weight of dimethacrylates and / or divinyl compounds,

b) 5 to 60% by weight of ethylenically unsaturated monomers with a functional group,

c) 5 to 91 wt .-% ethylenically unsaturated monomers and

d) 0.1 to 20% by weight of ethylenically unsaturated monomers with a tertiary amino group.

Examples of component d) are N, N'-dimethylaminoethyl methacrylate, N, N'-diethylaminoethyl methacrylate, 2-vinylpyridine and 4-vinylpyridine, vinylpyrroline, vinylquinoline,

Vinylisoquinoline, N, N'-dimethylaminoethyl vinyl ether and 2-methyl-5-vinylpyridine. In this case, components A) and / or B) contain tertiary amino groups which catalyze the crosslinking reaction. Furthermore, these tertiary amino groups catalyze, for example, transesterification reactions with acrylic acid esters or methacrylic acid esters, which may be desirable.

The invention also relates to a process for the preparation of a curable composition comprising, as component A), compounds having at least two activated double bonds (I), which are d, _/ 3-unsaturated carbonyl compounds,; , 3-unsaturated carboxylic acid esters or α. ^ - Unsaturated nitriles, and compounds B) which have at least two active hydrogen atoms or at least 2 groups contain active hydrogen atoms or at least one active hydrogen atom and at least one group with an active hydrogen atom, and conventional additives, catalysts, optionally pigments and organic solvents, characterized in that we first produce the soluble branched acrylate copolymer (P) by Copolymerization of

b) 5 to 60 wt.% _^ monomers having a functional group and c) 5 to 92 wt .-% of other ethylenically unsaturated monomers,

the sum of a), b) and c) being 100% by weight in an organic solvent at 70 to 130 ° C, preferably at 90 to 120 ° C, using at least 0.5% by weight , preferably at least 2.5 wt .-%, based on the total weight of the monomers a), b) and c), of a polymerization regulator and using tion initiators ^"of Polymerisa¬, wherein a pre-crosslinked, non-gelled product is obtained, and then

the soluble branched acrylate copolymer (P) with a

Compound (1) is implemented, in addition to a group reactive with (P) at least one active double bond

(I) contains, whereby the component (A) is obtained, and / or

the branched soluble acrylate copolymer (P) is reacted with a compound (2) which, in addition to a group which is reactive with (P), contains at least one active hydrogen atom or at least one group with an active hydrogen atom, giving (B),

and (A) and (B) in organic solvent, optionally with pigments and conventional additives, by mixing and if necessary dispersing to a coating composition - and a catalyst is added shortly before use for curing.

In the production of the Acrylatcopoly eren (P) it is important to ensure that a pre-crosslinked but not gelled copolymer is obtained. This is through appropriate

Polymerization conditions possible. The use of monomers with at least two ethylenically unsaturated groups results in a pre-crosslinking of the acrylate copolymer, which nevertheless does not lead to gelled products due to the special reaction conditions. It is important that the polymerization is carried out at temperatures from 70 to 130 ° C., preferably at 90 to 120 ° C., with a relatively low polymerization solids content of about 50% by weight. Compounds containing mercapto groups, preferably mercaptoethanol, are preferably used as the polymerization regulator. The selection of the controller depends in particular on the type of monomer component b). If the monomer component b) contains alkyl ester groups and is then to be transesterified or amamidated with alcohols or amines, it makes sense to use little or no mercaptoalcohols as regulators, since otherwise there is a risk of premature gelation during the transesterification or transamidation consists.

If the monomer component b) is an OH monomer and the resulting hydroxyl group-containing acrylate copolymer is to be reacted with a compound containing carboxyl groups in an esterification reaction, it makes sense to use little or no mercaptocarboxylic acids as regulators, otherwise there is a risk of gelling. It should be mentioned at this point that, for example, 2-mercapropionic acid can still be used in these cases, since this compound has a carboxyl group on a secondary, saturated carbon atom and is therefore less reactive than an o, ^ -unsaturated carboxylic acid. There must always be a match between the monomers b) and the selection of the controller must be done, for example, can further primary mercaptans and ethylenically unsaturated monoethylenically mers with isocyanate and glycidyl group-containing ethylenically unsaturated monomers and mercapto carboxylic acids ^"are not combined with each other as regulator.

The selection of the polymerization initiator depends on the proportion of the polyethylenically unsaturated monomers used. If the proportion is low, the initiators customary for such temperatures, e.g. Peroxyester, use. If the proportion of the polyethylenically unsaturated monomers is higher, initiators such as e.g. Azo compounds used.

In the reactions of the functional acrylic copolymer

(P) with the compounds (1) and (2) which lead to the formation of components (A) and (B), depending on the type of functional group of the acrylate copolymer, are known to the person skilled in the art Reactions such as

Esterification reactions, transesterification reactions, transamidation reactions, addition reactions with formation of urethane bonds, urea bonds, hydroxyester groups.

The reaction between components (A), the Michael acceptor component, and component (B), the Michael donor component is catalyzed by bases. The catalysts are added shortly before processing the mixture of components A) and B). From US Pat. No. 4,408,018, strong bases, such as alkali metal hydroxides or alkali metal alcoholates, are known as catalysts for the Michael addition. However, this leads to severe yellowing and clouding of the coating agent.

In the present invention, all possible catalysts for Michael addition can be used, provided that they do not lead to yellowing of the coating agents. Suitable Nete bases that can serve as catalysts for the Michael addition are described in DE-OS 35 08 399.

The use of catalysts can largely be dispensed with if tertiary amino groups are present in component A) and / or in component B). In this case, it is advisable to mix components A) and B) with KU erstZ before processing.

Suitable Michael catalysts are, for example, catalysts from the group of diazabicyclo-octane, halides of quaternary ammonium compounds, alone or in a mixture with silicic acid alkyl esters, amidines, organic phosphonium salts, tertiary phosphines, quaternary ammonium compounds or alkali metal alcoholates. The amount of the catalyst is generally 0.01 to 5, preferably 0.02 to 2,% by weight, based on the total solids content of the starting product.

The curable compositions according to the invention cure in the temperature range from room temperature to about 100 ° C., but can also be used at higher temperatures

The low curing temperatures make them particularly suitable for automotive refinishing.

However, they can also be used as a clear lacquer, filler or topcoat and as a base lacquer containing metal pigments or as a clear lacquer of a multi-layer metallic lacquer.

The coatings obtained from the curable compositions have very good resistance to solvents and chemicals.

The invention is explained in more detail below on the basis of exemplary embodiments: Production of a branched acrylate according to the invention

Pl:

In a 4 liter stainless steel kettle are placed and heated to 100 ° C:

477 parts of xylene

477 parts of cumene ^* -

Weigh and mix in the monomer tank:

150 parts of hexanediol diacrylate

250 parts of hydroxyethyl methacrylate

150 parts of ethylhexyl methacrylate

200 parts of tert-butyl methacrylate

100 parts of cyclohexyl methacrylate

150 parts of styrene

38 parts of mercaptoethanol

The following are weighed into the initiator tank and mixed: 28 parts of 2,2'-azobis (2-methylbutanenitrile), 56 parts of xylene and 56 parts of cumene

The content of the monomer tank is metered in in 3 hours, the content of the initiator tank is metered in 3.5 hours. The feeds are started simultaneously and the temperature is kept at 110 ° C. during the polymerization. The clear acrylic resin solution thus obtained has a viscosity of 2.9 dPas and a solids content of 51%.

Production of component AI:

In a stainless steel kettle, 920 parts of the acrylic resin solution P1 are mixed with 369 parts of ethyl acrylate and 2.46 parts of hydroquinone monomethyl ether and 4.92 parts of dibutyltin oxide and slowly heated to 80 to 100 ° C. An air flow is constantly passed through the boiler. After several hours at this temperature it slowly gets under Distilling off (via column) ethanol raised the temperature to 120 ° C. A total of 520 parts of ethanol and excess ethyl acrylate and some solvent were distilled off; it is then dissolved in 257 parts of butyl acetate.

The solids content of component AI thus obtained is 54.7%, the viscosity is 1.3 dPas.

Production of component B1:

In a stainless steel kettle, 960 parts of the acrylic resin solution P1 are mixed with 108 parts of ethyl acetoacetate and slowly heated to 80 to 100 ° C. With slow heating to 130 ° C, ethanol is distilled off over a column. Component B1 thus obtained has a solids content of 55.7% and a viscosity of 2.1 dPas.

Preparation of the acrylic resin solution P2:

In a 4 liter stainless steel kettle are placed and heated to 110 ° C:

483 parts xylene 483 parts cumene

150 parts of hexanediol diacrylate are weighed into the monomer tank with mixing

250 parts of hydroxyethyl methacrylate

150 parts of ethyl hexyl acrylate

100 parts of cyclohexyl methacrylate

200 parts of tert-butyl acrylate

150 parts of styrene

38 parts of mercaptoethanol

Weigh and mix in the initiator tank

24 parts of 2,2'-azobis (2-methylbutanenitrile) 48 parts of xylene

48 parts of cumene The content of the monomer tank is added in 3 hours, the content of the initiator tank is added in 3.5 hours, the temperature in the boiler is kept at 110 C, the initiator feed is started 10 minutes later than the monomer feed; it is polymerized for 3 hours after the end of the feed. The clear acrylic resin solution P2 thus obtained has a viscosity of 4.6 dPas and a solids content of 50.2%.

Production of component B2:

1041 parts of the acrylic resin solution P2 and 138 parts of ethyl acetoacetate are heated to 80 to 100 ° C in a stainless steel kettle. The mixture is then slowly heated to 130 ° C. on a column while ethanol is distilled off. Component B2 thus produced has a viscosity of 2.2 dPas and a solids content of 54.8%.

Production and testing of clear lacquer extracts:

Clear coat 1:

15.85 parts of trimethylolpropane triacrylate and 84.15 parts of component B2 and

0.4 part of 1,8-diazabicyclo (5,4,0) -7-undecenes are mixed and knocked onto glass plates with 150 μm wet film thickness and dried as indicated.

30 min / 80 ° C:

Pendulum hardness after oven: 175 seconds; resistant to petrol after 3 hours.

Room temperature:

Pendulum hardness after 6 hours: 160 seconds; Super gasoline resistant after 6 hours. Clear coat 2:

39.89 parts of reaction product from one mole of trimerized hexamethylene diisocyanate and three moles of hydroxybutyl acrylate and 60.11 parts of component B1 and

0.4 part of 1,8-diazabicyclo (5,4,0) -7-undecenes are mixed and kneaded with 150 μm wet film starch on glass plates and dried as indicated.

30 min / 80 ° C:

Pendulum hardness after oven: 175 seconds; resistant to petrol after 3 hours.

Room temperature:

Pendulum hardness after 6 hours: 81 seconds; resistant to petrol after 6 hours.

Claims

1. Curable composition, containing as a component

A) Compounds with at least two activated Doppelbin- 'fertilize (I), which are <, (!> -Unsaturated carbonyl compounds, t. (^ - unsaturated carboxylic acid esters or c _* , -unsaturated nitrile groups, and compounds B) , which contain at least two active hydrogen atoms or at least two groups with active hydrogen atoms or at least one active hydrogen atom and at least one group with an active hydrogen atom and conventional additives, catalysts, optionally pigments and organic solvents, characterized in that either component A ) or the component

B) or components A) and B) are based on a branched, soluble acrylate copolymer (P), which is obtainable by copolymerization of

b) 5 to 60 wt .-% monomers with a functional group and

c) 5 to 92% by weight of further ethylenically unsaturated monomers,

the sum of a), b) and c) being 100% by weight.

2nd A process for the preparation of a curable composition according to claim 1, comprising as component A) compounds with at least two activated double bonds (I), which are ot, ji-unsaturated car-bonyl compounds, c _* . , ß-Unsaturated carboxylic acid esters or et, (* -unsaturated Ni tri le and compounds B) which contain at least two active hydrogen atoms or at least two groups with active hydrogen atoms or at least one active hydrogen atom and at least one group with an active hydrogen atom, and conventional additives, catalysts, optionally pigments and Organic solvent, characterized in that first the soluble branched acrylate copolymer (P) is prepared by copolymerization of

b) 5 to 60 wt .-% monomers with a functional group and

c) 5 to 92% by weight of further ethylenically unsaturated monomers,

wherein the sum of a), b) and c) is 100% by weight in an organic solvent at 80 to 130 C, preferably at 90 to 120 C, using at least 0.5% by weight, preferably at least 2.5% by weight, based on the total weight of the monomers a), b) and c), of a polymerization regulator and using polymerization initiators, a pre-crosslinked, non-gelled product being obtained, and then

the soluble branched acrylate copolymer (P) is reacted to form (A) with a compound (1) which, in addition to a group reactive with (P), contains at least one activated double bond (I), and / or

the branched soluble acrylate copolymer (P) is reacted with a compound (2) to form (B), which contains at least one active hydrogen atom or at least one group with an active hydrogen atom in addition to a group which is reactive with (P), and (A) and (B) in organic solvent, if appropriate with pigments and customary additives, by mixing and, if appropriate, be processed into a curable composition and a catalyst is added shortly before use for curing.

3. Composition according to claim 1, characterized in that component (A) is obtainable by reacting the branched soluble acrylate copolymer (P) with a. Compound (1) which contains at least one activated double bond (I).

Composition according to Claim 1, characterized in that component (B) can be obtained by reacting the branched, soluble acrylate copolymer (P) with a compound (2) which, in addition to a group which is reactive with the acrylate copolymer, has at least one active hydrogen atom or at least one contains a group with an active hydrogen atom.

5. Composition or method according to claim 3, characterized in that component b) of the Acrylatcopoly¬ merisats a hydroxyl group-containing monomer and the compound (1) is a monoester of a cd, -unsaturated carboxylic acid. - - -

Composition or process according to Claim 3, characterized in that component b) of the acrylate copolymer is a monomer containing hydroxyl groups and the compound (1) is an α-, (^ -unsaturated carboxylic acid.

7. Composition or method according to claim 3, characterized in that component b) of the Acrylatcopoly¬ merisat is a hydroxyl group-containing monomer and the compound (1) contains, in addition to group (I), an isocyanate group. '

8. The composition or process according to claim 3, characterized in that component b) of the acrylate copolymer is a monomer containing hydroxyl groups and the compound (1) is an alkoxymethyl group-containing amide of a, b -unsaturated carboxylic acid or the compound (1 ) of the general formula

R 0 R ¹ i II I p CH ₂ = CCNX-COOR, with R = H, CH ₃

R ¹ = H, alkyl, aryl

R ² = alkyl

X =

9. The composition or method according to claim 3, characterized in that the monomer b) contains an epoxy group and the compound (1) has a carboxyl or amino group.

10. The composition or method according to claim 3, characterized in that component b) contains an ester function, the esterification alcohol not containing more than 6 carbon atoms, and the compound (1) in addition to group (I) a 0H, NH or SH group contains.

11. The composition or method according to claim 3, characterized in that the monomers b) contain isocyanate groups and the compound (1) in addition to the group (I) have OH, NH, SH or COOH groups.

12. The composition or method according to claim 3, characterized in that b) an alkoxymethyl group containing amide of a ^, 0> unsaturated carboxylic acid or a compound of general formula 1

R 0 R ι II ι o CH ₂ = CCNX-C00R

with R = H, CH ₃ R ¹ = H, alkyl, aryl

R ² = alkyl

X = -C-, -CH-, -CH-, -CH-

^{H l} _χ 'i' i

0 R OR C00R

is

13. The composition or method according to claim 4, characterized in that the monomer component b) is a monomer containing hydroxyl groups and the compound (2) contains an ester or acid group in addition to the active hydrogen atoms or the group with active hydrogen atoms.

14. The composition or method according to claim 4, characterized in that b) are monomers with glycidyl groups and (2) in addition to group (I) contains a C00H or NH group.

15. The composition or method according to claim 4, characterized in that the monomer component b) contains a carboxyl group and the compound (2) is a reaction product of a polyepoxide with n mol of epoxy group. pen and (n-1) mole of a compound having CQOH or NH groups and the group having active hydrogen.

16. The composition or method according to claim 5, characterized in that the compound (1) ester c *. (-Ethyle¬ nisch- unsaturated carboxylic acids, their Alkoholkom¬ component up to 6 carbon ^atoms'.

17. The composition or method according to claim 7, characterized in that the compound (1) is an isocyanato-alkyl ester of unsaturated carboxylic acids of the general formula

R 0

I II CH ₂ = CC-0-X-NC0, where R = H, CH ₃ , C ₂ Hg and X = (CH d ₉ ) n with n = 1-12

mean or that the compound (1) is m-isopropenyl ° C, <x - dimethylbenzyl isocyanate or is selected from the group of reaction products of diisocyanates with OH-, NH-, SH- or COOH-functional derivatives of acrylic acid, methacrylic acid , Fumaric acid, maleic acid, crotonic acid and dimethylacrylic acid.

18. Composition or method according to claim 8, characterized in that the compound (1) is selected from the group methoxymethyl acrylate mid, methoxymethyl methacrylate mid, butoxymethylacrylamide, butoxymethyl methacrylamide, isobutoxymethylacrylamide, isobutoxymethyl methacrylamide, analogous amides of fumaric acid, chrotonic acid and of dimethylacrylic acid, glycolic acid derivatives, such as methyl crylamidoglycolate methyl ether, butylacrylamido glycolate butyl ether, methyl acrylamidoglycolate, butyl acrylamide glycolate.

19. The composition or process according to claim 9, characterized in that the compound (1) is selected from the group consisting of acrylic acid, methacrylic acid, chrotonic acid, dimethylacrylic acid, fumaric acid, monomethyl ester,. of the reaction products of acid anhydrides and hydroxy 'alkyl esters <x, (^ - unsaturated acids, or t-butylaminoethyl methacrylate or bisacrylamidoacetic acid or bis (acrylamidoethyl) amine.

20. Composition or method according to claim 10, characterized in that the compound b) is selected from the group of the hydroxyalkyl esters o, ^ - unsaturated carboxylic acids, such as methyl, ethyl, propyl, butyl, isobutyl, isopropyl, Hexyl ester of acrylic acid, methacrylic acid, fumaric acid, crotonic acid, dimethylacrylic acid and the aminoalkyl ester of the aforementioned o, (i-unsaturated carboxylic acids.

21. The composition or method according to claim 11, characterized in that the monomers b) are selected from the group m-isopropenyl - <*, <.- dimethylbenzyl isocyanate, the isocyanatoalkyl esters d, β-unsaturated carboxylic acids and the adducts, for example of Isophorone diisocyanate on hydroxyalky1 (meth) acry1ate.

22. The composition or method according to claim 12, characterized in that b) is selected from the group N-alkoxymethyl (meth) crylamide, alkox uneth) acrylamidoglycolate alkyl ether, such as methoxymethylacrylamide, isobutoxymethylacrylamide.

23. Composition or method according to claim 13, characterized in that the monomers b) are hydroxyalkyl esters d. (!> - unsaturated carboxylic acids and the compound (2) is selected from the group acetoacetic acid,

Cyanoacetic acid, malonic acid, cyclopentanone carboxylic acid, cyclohexanone carboxylic acid and the respective alkyl esters.

24. The composition or method according to claim 14, characterized in that the compound (2) is selected from the group acetoacetic acid, cyanoacetic acid, malonic acid, cyclopentanone carboxylic acid, cyclohexanone carboxylic acid.

25. Composition or procedure _. according to claim 15, characterized in that the compound (2) is a reaction product of one mole of trimethylolpropane triglycidyl ether and two moles of cyanoacetic acid or two moles of acetoacetic acid.

26. The composition or method according to claim 1 to 25, characterized in that component a) of the general formula

R 0 0 R

I II II I

CH = CCX- (CH ά, ₅ ) nXCC = CH d

corresponds in which mean:

R = H or CH ₃ ,

X = 0, NR ', S with R ¹ = H, alkyl, aryl n = 2 to 8.

27. The composition or method according to claim 1 to 25, characterized in that component a) is a reaction product of a carboxylic acid with a polymerizable, olefinically unsaturated double bond and glycidyl acrylate and / or glycidyl methacrylate.

28. The composition or method according to claim 1 to 25, characterized in that component a) is a polycarboxylic acid or unsaturated monocarboxylic acid esterified with an unsaturated alcohol containing a polymerizable double bond.

29. The composition or method according to claim 1 to 25, characterized in that component a) can be prepared by reacting a polyisocyanate with unsaturated alcohols or amines containing polymerizable double bonds.

'30. Composition or process according to Claims 1 to 25, characterized in that component a) is a diester of polyethylene glycol and / or polypropylene glycol with an average molecular weight of less than 1500, preferably less than 1000, and acrylic acid and / or methacrylic acid.

31. The composition or method according to claim 1, 2, 3, 5 to 12 and 16 to 22, characterized in that the soluble branched acrylate copolymer is obtainable by copolymerizing a) 3 to 30% by weight of dimethacrylates and / or divinylver - ties,

c) 5 to 91 wt .-% ethylenically unsaturated monomers and

d) 0.1 to 20% by weight of ethylenically unsaturated monomers with a tertiary amino group,

wherein the sum of a), b), c) and d) is 100% by weight and the branched acrylate copolymer obtained is then reacted with the compound (1) to component A).

32. Composition or method according to claim 1, 2, 4, 13 to 15 and 23 to 25, characterized in that the soluble branched acrylate copolymer (P) is obtainable by cooolimerization of la) 3 to 30 wt .-% dimethacrylate monomers and / or

Divinyl compounds,

b) 5 to 60% by weight of ethylenically unsaturated monomers 5 with a functional group,

c) 5 to 91 wt .-% ethylenically unsaturated monomers and

d) 0.1 to 20% by weight of monomers with a tertiary amino group,

the sum of a), b), c) and d) being 100% by weight and the soluble branched acrylate copolymer (P) then being reacted with the compound (2) to give the component (B).

33. The method according to claim 2 to 32, characterized gekennzeich¬ net that mercapto-containing compounds, preferably mercaptoethanol, are used as the polymerization regulator.

34. The method according to claim 2 to 33, characterized gekennzeich¬ net that peroxyesters and / or azo compounds are used as polymerization initiators.

35. Use of the curable composition according to claim 1 and 3 to 33 for automotive refinishing.

36. Use of the curable composition according to claim 1 and 3 to 32 as a clear coat, filler or top coat.

37. Use of the curable composition according to claims 1 and 3 to 32 as a base coat containing metal pigments and / or as a clear coat of a multi-layer metallic paint system.