EP0436558A1

EP0436558A1 - Composition based on a michael addition product, methods for preparing it and its use

Info

Publication number: EP0436558A1
Application number: EP89909189A
Authority: EP
Inventors: Werner Alfons Jung; Peter Hoffmann
Original assignee: BASF Lacke und Farben AG
Current assignee: BASF Farben und Fasern AG
Priority date: 1988-09-28
Filing date: 1989-08-11
Publication date: 1991-07-17
Also published as: WO1990003404A1; NO176916B; BR8907681A; JPH07103290B2; DK48591D0; KR900005362A; DE3832958A1; ZA896632B; NO176916C; NO911134L; DE58904474D1; ATE89835T1; DK48591A; ES2058421T3; AU632500B2; EP0361048B1; JPH03502816A; AU4051989A; NO911134D0; EP0361048A1

Abstract

The invention concerns a curable composition containing A) compounds with at least two activated double bonds (I) based on alpha , beta -unsaturated carbonyl compounds, alpha , beta -unsaturated carboxylic esters or alpha , beta -unsaturated nitrile groups; B) compounds containing either at least one primary amino group blocked by an aldehyde or ketone with not more than 10 carbon atoms or at least two groups which can be hydrolysed to NH groups; and C) ordinary additives, possibly catalysts, possibly pigments and organic solvents. Component A or component B or component A and B are based on a branched, soluble acrylate copolymerizate P which can be obtained by copolymerization of a) 5 to 30 wt.% of monomers with at least ethylenically unsaturated polymerizable double bonds, b) 5 to 60 wt.% of momomers with one functional group and c) 5 to 90 wt.% of other ethylenically unsaturated monomers, the sum of a), b) and c) being equal to 100 wt.%. The invention also concerns methods for preparing the curable composition and its use.

Description

Curable composition based on a Michael addition product. Process for its production and its use

The invention relates to a curable composition containing

A) compounds with at least two activated double bonds (I) based on 06, (3-unsaturated carbonyl compounds, «4, β-unsaturated carboxylic acid esters or. O, β-unsaturated nitrile groups,

B) Compounds which contain either at least one primary amino group which is blocked with an aldehyde or ketone with not more than 10 C atoms or at least 2 groups which can be hydrolyzed to NH groups and

C) usual additives, optionally catalysts, optionally pigments and organic solvents.

The present invention also relates to processes for the preparation of these compositions and their use.

Compositions are known from EP 160 824 which are obtained by reacting compounds with at least two activated double bonds (I) with compounds which contain active hydrogen atoms. These compositions react under the influence of bases to form a Michael addition product. The Michael acceptor component can, for example, be derived from acrylate resins containing hydroxyl groups, epoxy resins, oligomeric polyols or oligomeric polyamines. The Michael donor component can be derived, for example, from polyols, polyamines or polymercaptans. The binders described in EP 160 824 can be used as two-component systems for

Covers are used. They cure easily under the catalysis of bases at room temperature and at elevated temperatures. The advantages of the systems described are that they do not require free isocyanates for curing. However, the known systems are disadvantageous with regard to solvent resistance, chemical resistance and elasticity of the coatings obtained from them.

Compositions are known from EP 230 296 which are obtained by reacting compounds with at least two activated double bonds with compounds which contain at least one primary amino group which are blocked with an aldehyde or ketone. These compositions react under the influence of atmospheric humidity at different temperatures to form a Michael addition product. However, these compositions are in need of improvement in terms of solvent resistance and chemical resistance of the coatings produced from them. A further disadvantage of these compositions is the high solvent content of the coating compositions, which is caused by the high viscosity of the binder solutions, since it leads to a high solvent pollution of the environment when the coating films dry. In the older, unpublished patent application DE 37 10 431, curable compositions are described which contain compounds A with at least two activated double bonds and compounds B with active hydrogen atoms. These compositions react under the influence of bases to form a Michael addition product. At least one of the compounds A and B is based on a branched acrylate copolymer P which is soluble in organic solvents. In contrast to the present application, only carbonyl compounds selected from the group acetoacetic acid, cyanoacetic acid, malonic acid, cyclopentanone carboxylic acid, cyclohexanone carboxylic acid, some alkyl esters and the reaction products of these carbonyl compounds with hydroxyl- and glycidyl-containing acrylate copolymers. Compounds B containing amino groups are not described.

Di® 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. 3 to 25% by weight of monomers with at least two polymerizable, olefinically unsaturated double bonds are used in the polymerization for the preparation of the acrylate copolymer. 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 crosslinking agents have a disadvantageous effect for toxicological reasons. The invention was therefore based on the object of providing coating compositions which can cure at low temperatures, are therefore preferably used in automotive refinishing and are largely free of isocyanate. In particular, these coating compositions should paint films with - in relation to the systems of EP 160 824 and EP 230 296 - improved solvent Mitt same _^^^ ^ tändigkeit and perform chemical resistance. Furthermore, these coating compositions should have the highest possible solids content at a viscosity of 16 to 20 s, which is favorable for processing, measured in the discharge cup according to DIN 4 at 23 ° C.

Surprisingly, this task is curable. Coating composition solved that

A) compounds with at least two activated double bonds (I) based on e, unsaturated carbonyl compounds, cl, unsaturated carboxylic acid esters or *, unsaturated nitrile groups,

B) Compounds which have either at least one primary amino group which is blocked with an aldehyde or ketone with no more than 10 C atoms or at least 2

Groups that are hydrolyzable to NH groups contain and

C) usual additives, optionally catalysts, optionally pigments and organic solvents

contains and which is characterized in that either component A or component B or components A and B are based on a branched soluble acrylate copolymer P, which is obtainable by copolymerization of ^a ) 5 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 90% by weight of further ethylenically unsaturated monomers,

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

Compounds A are compounds which contain activated olefinically unsaturated groups and can serve as a Michael acceptor. Component B are compounds which contain either at least one primary amino group - blocked with ketones or aldehydes - or at least 2 groups which can be hydrolyzed to NH groups and can serve as a Michael donor. According to the invention, at least one of components A and B should be based on the branched, soluble acrylate copolymer P, ie it should be obtainable therefrom. 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 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 P, comprises at least one primary amino group which is no longer associated with a ketone or aldehyde is blocked as 10 C atoms, or contains at least 2 groups that can be hydrolyzed to NH groups. The soluble branched acrylate copolymer P with a number average molecular weight of 1,500 to 5,000 (weight average 6,000 to 100,000) is therefore used according to the invention as a precursor for the compounds A and / or B. The branched acrylate copolymer can be obtained by copolymerization of 5 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 o R I II ιι |

CH ₂ = CCX- (CH ₂ ) _n -XCC = CH,

With

R = H or CH_

X = 0, NR ', S with R' = 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. Furthermore, di inyl compounds such as divinylbenzene are also 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 monocarboxylic acid esterified with an unsaturated alcohol containing a polymerizable double bond.

As component a, reaction products of a polyisocyanate with unsaturated alcohols or amines containing polymerizable double bonds are advantageously used. An example of this is the reaction product from 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, croton, isoerotonic, vinyl acetic and fumaric acid. le as further Beispie¬ lat be mentioned methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isopropyl acrylate, isobutyl acrylate, Pentylacry-, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, 3,5,5-trimethylhexyl acrylate, decyl acrylate, dodecyl acrylate, hexadecyl acrylate, octadecyl acrylate, octad cenyl acrylate, pentyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate,

3,5,5-trimethylhexyl methacrylate, decyl methacrylate, dodecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, butoxyethyl acrylate, butoxyethyl methacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, isobutyl methacrylate

Cyclohexyl methacrylate, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, phenoxyethyl methacrylate and phenoxyethyl acrylate. Further monomers can be used, provided that they do not lead to undesirable properties of the copolymer. The selection of component c largely depends on the desired properties of the acrylate copolymer in terms of 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 ε-caprolactone. Monomers containing hydroxyl groups can also contain esters containing hydroxyl groups acrylic acid and / or methacrylic acid can be used with a secondary hydroxyl group. These are advantageously reaction products of acrylic acid and / or methacrylic acid with the glycidyl ester of a carboxylic acid with a tertiary eC carbon atom. Examples of hydroxyl-containing ethylenically unsaturated monomers are hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyamyl acrylate, hydroxyhexyl acrylate, hydroxyoctyl acrylate and the corresponding methacrylates. Examples of OH monomers with a secondary OH group are 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate and the corresponding methacrylates.

Compositions according to the invention are advantageous in which component A is based on a soluble crosslinked acrylic copolymer, component b of the acrylic copolymer being a monomer containing hydroxyl groups, and compound (1) being a monoester • CE-unsaturated car- is acidic. In this case, the branched copolymer containing hydroxyl groups is reacted in a transesterification reaction after the polymerization with monoesters of et, 3-unsaturated carboxylic acids, 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. In this case, the compounds (1) of f3-unsaturated carboxylic acids 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, are advantageously used in this case , the corresponding methacrylates and the corresponding esters of fumaric acid, maleic acid, crotonic acid, dimethyl acrylic acid. The compounds (1) are branched in known transesterification reactions with the OH groups Acrylate copolymer P implemented.

Further production methods for component A are described below:

Component A is advantageously based on a soluble, pre-crosslinked acrylate copolymer P, the component b of which is a monomer containing hydroxyl groups, and the hydroxyl group-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.

Component A can furthermore advantageously be prepared by reacting the previously described hydroxyl group-containing acrylate copolymer P with a compound which, in addition to group (I), contains an isocyanate group. In this case, the reaction between this compound (1) and the branched acrylate copolymer takes place 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 formula

R 0 CH ₂ = CC-0-X-NC0,

where R - H, CH_, C ₂ H ₅ and X »(CH_) with n = 1-12

mean; but it can also be m-isopropenyl - *, «* -dimethyl-benzyl 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.

To produce component A, the branched acrylate copolymer containing hydroxyl groups is advantageously reacted with a compound (1) which contains an amide of an alkoxymethyl group. , γ-unsaturated carboxylic acid or the general formula

, R 0 R ¹

I II I ₀

CH ₂ ^{■ * ■} = CCNX-COOR

corresponds to

Examples of such compounds are methoxymethylacryl amide, methoxymethyl methacrylamide, butoxymethylacrylamide, butoxymethyl methacrylamide, isobutoxymethylacrylamide, isobutoxymethyl methacrylate, analog amides of fumaric acid, cotronic acid and dimethylacryl amyl acrylamide, such as methylacryl amyl acrylamide, such as methylacryl acrylamide, such as methylacryl acrylate, such as methylacryl acrylate, such as methyl acrylamide

Component A, which is based on a branched soluble acrylic copolymer and contains at least two activated double bonds, can also be prepared by reacting an acrylate copolymer containing epoxy groups. risats and a compound (1) containing a carboxyl or amino group. In this case, a monomer containing epoxide groups, such as, for example, glycidyl ester of unsaturated carboxylic acids or glycidyl ether of unsaturated compounds, is used as monomer b to prepare the acrylate copolymer P. Examples of component b are: glycidyl acrylate, glycidyl methacrylate, glycidyl ester of maleic and fumaric acid, glycidyl vinyl phthalate, glycidyl allyl phthalate, glycidyl allyl malonate. 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 from carboxylic acid anhydrides and hydroxyalkyl esters ct, (3-unsaturated acids, such as adducts from hexahydrophthalic anhydride, phthalic anhydride, phthalic anhydride) or maleic anhydride and hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate. Compound (1) can also be t-butylaminoethyl (meth) acrylate, bisacrylamino-diacetic acid or bis (acrylamidoethyl) amine. Compounds with several activated double bonds are particularly preferably used, such as bisacrylamidoacetic acid.

The branched soluble acrylate copolymer P can contain, as functional monomer b, monomers with ester functions. Advantageously, the esterification alcohol should 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. As component b are alkyl esters of acrylic acid, methacrylic acid, crotonic acid, maleic and fumaric acid, such as the corresponding methyl, ethyl, propyl, isopropyl, Butyl, isobutyl and pentyl esters. Longer-chain alcohol residues in the ester group are less favorable since their transesterification and distillation after the transesterification require excessively high temperatures. Aminoalkyl esters of the * L, β-unsaturated carboxylic acids mentioned 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.

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 resulting isocyanate group-containing acrylate copolymer is then reacted with compounds (1) which, in addition to group (I), contain OH, NH, SH or COOH groups. In this case the monomers b can be selected from the group of vinyl isocyanates, such as e.g. Vinyl isocyanate and m-isopropenyl, dimethylene benzyl isocyanate, isocyanato alkyl ester, and unsaturated carboxylic acids of the general formula

R 0

I II CH ₂ = CCOX-NCO,

where R - H, CH ₃ , C ₂ H ₅ and X - (CH2Vn 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, contain two or more structural elements (I). That way, with an addition step introduced two or more double bonds of type (I). This is advantageous in that urethane or urea groups are formed when hydroxyl groups are added to isocyanate groups, which generally greatly increase the viscosity of the binders, which is not always desirable. The reaction products of acrylic acid or methacrylic acid or another * (, - .beta.-ethylenically unsaturated carboxylic acid and glycidyl acrylate or glycidyl methacrylate are examples of this. This reaction produces a free hydroxyl group which is then added to the NCO groups of the acrylate copolymer .

Advantageously, the monomer component b for producing the acrylate copolymer can contain an alkoxymethyl group-containing amide of a ci, β-unsaturated carboxylic acid or a compound of the general formula

R 0 R ι u ι CH ₂ = CCNX-C00R

be with R = H, CH ₃ , R ¹ _ = H, alkyl, aryl R ² = alkyl X = -C-, -CH-, -CH-, -CH-

0 R ¹ OR ¹ 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, methoxy methyl methacrylamide, isobutoxia acrylamide, isobutoxime methacrylamide and isobutoxime methyl methacrylamide. The alkoxy (meth) acrylamidoglycolate alkyl ethers are also suitable.

The compounds B are compounds which contain either at least one primary amino group which is blocked with an aldehyde or ketone with not more than 10 atoms or at least 2 groups which can be hydrolyzed to form NH groups and which as Michael Donator can serve.

Examples of suitable compounds which are used in aldiminized or ketiminized form are aliphatic and / or cycloaliphatic amines having at least one, preferably two to four, primary amino groups and 2 to 24 carbon atoms. They preferably have number average molecular weights below 700. They also preferably have 0 to 4 secondary amino groups. Alkanolamines are also preferred. Examples of suitable amines are ethylenediamine, tri-, tetra-, penta-, hexa-, hepta-, nona-, deca- and dodeca- methylenediamine, 2,2,4- or 2,4,4-trimethylhexamethylene diamine, Propylene diamine, 1,3- or 1,4-butylene diamine, isophore diamine, 1,2- and 1,4-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, bis- (3-methyl-4-aminocyclohexyl) methane

2,2-bis (4-aminocyclohexyl) propane, 4,7-dioxadecane-l, 10-diamine, 4,9-dioxadodecane-l, 12-diamine, 7-methyl-4,10-dioxatride- can-l, 13-diamine, nitrilotris (ethanamine), ethanolamine, propanolamine, N- (2-aminoethyl) ethanol, polyether polyamines, bis (3-aminopropyl) methylamine, 3-amino-l-methylaminopropane, 3 -Amino-l- (cyclohexylamino-) propane, N- (2-hydroxyethyl) - ethylenediamine, tris- (2-aminoethyl-) amine and polyamines of the formula H ₂ N- (R ₂ ~ NH) -R, -NH_. n is an integer between 1 and 6, preferably 1-3, R _χ and R ₂ are the same or different alkylene groups or cycloalkylene Alkylene groups containing groups or ether groups with 2-6, preferably 2-4, carbon atoms. Examples of such polyalkylene polyamines are diethylene triamine, triethylene tetraamine, tetraethylene pentamine, dipropylene triamine, tripropylene tetramine, tetrapropylene pentamine and dibutylene triamine. Diethylenetriamine is particularly preferred.

Amino compounds which are also suitable as component B are the reaction products of an amine described in EP 203 296 which, in addition to the iminized (ie primary amino group which is blocked with an aldehyde or ketone with not more than 10 C atoms) primary amino group, also OH, Contains NH or SH groups, with a monoisocyanate, monoepoxide or a monofunctional ι, ß-unsaturated carbonyl compound. For more details, see the

EP 203 296 referenced. Cycloaliphatic amines with 5 to 15 carbon atoms, such as e.g. Isophoronediamine, 4,4'-dicyclohexylmethane diamine and 3,3'-Dirnethy1-4,4'dicyclohexylmethane diamine used. Also suitable as component B are reaction products of alkanolamines, mercaptylamines or primary amines, which also have an NH group, with di- and polyisocyanates, di- and polyepoxides and * i, β-unsaturated carbonyl compounds.

Examples of suitable di- or polyisocyanates are:

Aromatic isocyanates, such as 2,4-, 2,6-toluenediisocyanate and mixtures thereof, 4,4'-diphenylmethane diisocyanate, m-phenylene, p-phenylene, 4,4-diphenyl, 1,5-naphthalene -, 1,4-naphthalene, 4,4'-toluidine, xylylene diisocyanate and substituted aromatic systems, such as, for example, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanates or chlorodiphenylene diisocyanates and more highly functional aromatic isocyanates, such as 1, 3,5-triisocyanatobenzene, 4,4, "4" triisocyanate— triphenylmethane, 2,4,6-triisocyanatotoluene and 4,4'-diphenyldimethylmethane-2,2 ', 5,5 * -tetraisocyanate; cycloaliphatic isocyanates, such as 1,3-cyclopentane, 1,4-cyclohexane, 1,2-cyclohexane and isophorone diisocyanate; aliphatic isocyanates, such as, for example, trimethylene, tetramethylene, pentamethylene, hexamethylene, trimethylhexamethylene-1,6-diisocyanate and tris-hexamethylene triisocyanate.

Examples of suitable -i, unsaturated carbonyl compounds include <^, ß-unsaturated dicarboxylic acids or their esters, e.g. Maleic and fumaric acid.

For further details of amine adducts suitable as component B, reference is made to EP 203 296.

As already mentioned, the amines mentioned above are used in the form of the iminized compounds in the compositions according to the invention, i.e. the primary amino groups are blocked by reaction with an aldehyde or ketone with not more than 10 C atoms, preferably 3-8 C atoms. Ketones are preferably used. Examples of suitable aldehydes and ketones are acetone, methyl ethyl ketone, diethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, isobutyraldehyde, 2-pentanone, cyclohexanone, ethyl amyl ketone, diisobutyl ketone, 3-octanone and decanone. Methyl isobutyl ketone and ethyl amyl ketone are very particularly preferably used. This blocking reaction is known (cf. EP 203 296) and need not be described in more detail.

Of course, component B, which as

Michael Donator is used, based on the branched acrylate copolymer soluble in organic solvents. In the following, some manufacturing methods for the components te B, which is obtained from an acrylate copolymer with a functional group and the compound (2), represents.

The soluble branched acrylate copolymer preferably contains hydroxyl groups, which are preferably introduced into the acrylate copolymer as monomer b by the use of hydroxyalkyl esters and 1,3-unsaturated carboxylic acids. These hydroxyl-containing acrylate copolymers are reacted with compounds (2) which contain at least one primary amino group blocked with aldehydes or ketones with not more than 10 C atoms and an average of 0.8 to 1.5, preferably 1, free isocyanate group per molecule. The amount of compound (2) is chosen so that the resulting resin has an amine number of 30 to 200 mgKOH / g, preferably 60 to 150 mgKOH / g. This reaction of the acrylate copolymer containing hydroxyl groups with the compounds (2) is carried out in an isocyanatin-containing solvent at temperatures from 10 to 100 ° C., preferably 50 to 80 ° C., optionally in the presence of organic tin compounds as catalysts, up to an NCO value of practically zero.

The compounds (2) are prepared by reacting diisocyanates or polyisocyanates with a stoichiometric deficit of one or more polyamines with at least one primary amino group, which is blocked with an aldehyde or ketone with not more than 10 C atoms, and ei¬ ner isocyanate group reactive group. Examples of suitable amines are the alkanolamines with at least 4 carbon atoms already listed on page 15 of this description, amines with mercaptan groups and polyamines, preferably with differently reactive amino groups. The alkanolamines are preferably used ... The primary amino group of these compounds was added before the reaction with the isocyanates Aldehydes or ketones blocked with no more than 10 carbon atoms.

Examples of the di- and polyisocyanates suitable for the preparation of compound (2) are the compounds already listed on page 16/17 of this description. Diisocyanates with different reactive isocyanate groups, such as e.g. Isophorone diisocyanate used.

Another possibility is to use branched acrylate copolymers P containing isocyanate groups to prepare component B. In this case, monomers containing NCO groups, such as e.g. the compounds listed on page 13 of this description. This isocyanate group-containing acrylate copolymer P is then reacted with compounds (2) which, in addition to the iminized primary amino groups, contain OH, NH or SH groups. Examples of such compounds are listed on page 15 of this description.

There is also the possibility of containing glycidyl groups

To react acrylate copolymers P, which can be prepared by using monomers b with glycidyl groups - as explained on page 12 of this description - with compounds (2) which contain an NH group in addition to the iminized amino group (II). Examples of suitable compounds (2) are listed on page 15 of this description.

Of course, acrylate copolymers P which have been prepared using monomers b containing carboxyl groups can also be reacted with compounds (2) which are a reaction product of a polyepoxide having n moles of epoxy groups and (n-1) moles of a compound (3) which, in addition to iminized amino group (II) still has NH groups. Examples of suitable compounds (3) are, for example on page 15/16. Examples of suitable epoxy-amine adducts (2) are also listed in EP 203 296. Finally, there is also the possibility of using as component B compounds which have at least 2 groups which can be hydrolyzed to form NH groups. For further details, reference is made to EP 160 824.

The invention also relates to a method for producing a curable composition which

A) compounds with at least two activated double bonds (I) based on cL, β-unsaturated carbonyl compounds, eC, β-unsaturated carboxylic acid esters or • l, -unsaturated nitrile groups,

Groups that are hydrolyzable to NH groups contain and

C) usual additives, optionally catalysts, optionally pigments and organic solvents,

contains, characterized in that first the soluble branched acrylate copolymer P is prepared by copolymerization of

a) 5 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 90% by weight of further ethylenically unsaturated monomers,

wherein the sum of a, b and c is 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% by weight _; based on the total weight of the monomers a, b and c, a polymerization regulator and using polymerization initiators, a pre-crosslinked, non-gelled product being obtained, and then

the soluble branched acrylate copolymer P with a

Compound (1) is reacted which, in addition to a group capable of reacting, contains at least one active double bond (I), component A being 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 primary amino group which is blocked with an aldehyde or ketone with not more than 10 C atoms, B being obtained,

and A or B, preferably A, are processed in an organic solvent, if appropriate with pigments and customary additives, by mixing and, if appropriate, dispersing to give a coating composition, and shortly before use for curing, the other component (B or A), optionally added together with a catalyst.

When producing the acrylate copolymer P, care must be taken that a pre-crosslinked but not gelled copolymer is obtained. This can be 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 40 to 65% by weight. If divinylbenzene is used as monomer a, however, it is also possible to carry out the polymerization at temperatures of up to 140.degree. Compounds containing mercapto groups, preferably mercaptoethanol, are preferably used as polymerization regulators. 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 transamidated with alcohols or amines, it makes sense to use little or no mercapto alcohols as a regulator, since otherwise there is a risk of premature gelation during the transesterification or transamidation.

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 less or no mercaptocarboxylic acids as regulators , otherwise there is a risk of gelling. It should be mentioned at this point that, for example, 2-mercapto-propionic acid can nevertheless be used in these cases, since this compound has a carboxyl group on a secondary saturated carbon atom and is therefore less reactive than a <, β-unsaturated carboxylic acid. There must always be a coordination between the monomers b and the selection of the regulator. Furthermore, primary mercaptans and ethylenically unsaturated monomers with isocyanate groups as well as ethylenically unsaturated monomers and mercaptocarboxylic acids containing glycidyl groups cannot be combined as regulators.

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.

The reactions of the functional acrylate copolymer P with the compounds (1) and (2) which lead to the formation of components A and B are, depending on the type of functional group of the acrylate copolymer, reactions known to the person skilled in the art, such as Esterification reactions, transesterification reactions, transamidation reactions, addition reactions to form urethane bonds, urea bonds, 0-hydroxyester groups.

The curable compositions according to the invention also contain conventional additives and optionally pigments and organic solvents in conventional amounts.

Examples of customary additives are fillers, leveling agents, silicone oils, plasticizers, such as phosphoric acid esters and phthalic acid esters, viscosity-controlling additives, matting agents, UV absorbers and light stabilizers. These substances are preferably used in amounts of 0.1 to 20% by weight, based on the total composition. Examples of pigments which may be added are metal pigments, such as, for example, aluminum flake pigments and mica flakes coated with metal oxides (for example mica) as effect pigments, which are preferably used in amounts of 0.1 to 30% by weight, based on the overall composition. Color pigments can also be used, preferably in amounts of 0.1 to 60% by weight, based on the total composition.

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 coat, filler or top coat as well as a base coat containing metal pigments or as a clear coat of a multi-layer metallic coating.

These coating compositions can be applied by spraying, flooding, dipping, rolling, knife coating or brushing onto a substrate in the form of a film, the film then being cured to form a firmly adhering coating.

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. All information on parts and percentages are by weight unless expressly stated. what else is found.

Production of a branched acrylate copolymer P

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

677.3 parts xylene

Weigh and mix in the monomer tank:

120 parts of hexanediol diacrylate, 200 parts of hydroxyethyl methacrylate, 120 parts of ethylhexyl acrylate

80 parts cyclohexyl acrylate 160 parts tert-butyl acrylate 120 parts styrene

30 parts of mercaptoethanol

Weigh and mix in the initiator tank:

16 parts of 2,2 * -azobis (2-methylbutanenitrile) 169 parts of xylene

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 initiator feed is started 10 minutes later than the monomer feed. The temperature is kept at 110 ° C. during the polymerization. After the feeds have ended, polymerization is continued for 3 hours. The acrylate resin solution thus obtained has a viscosity of 7.6 dPas (measured at 23 ° C.) and a solids content of 49.6% (60 min 130 ° C.). Preparation of component A

After cooling to about 60 ° C., 477.5 parts of ethyl acrylate, 4.2 parts of hydroquinone and 8.5 parts of dibutyltin oxide are added to the acrylate copolymer solution P described above. The solution is slowly heated to 80 ° C. An air stream is continuously passed through the boiler during the reaction. After the solution had been kept at this temperature for 6 h, the temperature was slowly increased to 120 ° C. while distilling off (via column) ethanol. The excess ethyl acrylate and some solvent are then distilled off under vacuum. The acrylic resin solution thus obtained has a viscosity of 3.4 dPas (measured at 23 ° C.) and a solids content of 56% (60 min, 130 ° C.).

Preparation of ketimine component B

In a 2 liter glass kettle, a solution of 232 parts of a ketimine of ethyl amyl ketone (5-methyl-3-heptanone) and diethylenetriamine, dissolved in 84 parts of ethyl amyl ketone, is initially taken. A solution of 228 parts of a trimerized isophorone diisocyanate in 45.6 parts of xylene and 45.6 parts of 1-methoxypropyl acetate-2 is added to this solution within 120

Dripped minutes. The reaction temperature is kept at 35-40 ° C. The mixture is kept at 35 ° C. for a further 3 hours until infrared spectroscopic examination of the reaction mixture no longer shows any free isocyanate. Then 13.0. Parts of methoxypropanol were added. The ketimine solution obtained in this way has a solids content of 57% (60 min, 130 ° C.) and a viscosity of 6.4 dPas (at 23 ° C.). Production and testing of a clear lacquer coating:

25.89 parts of acrylic resin solution A and 7.74 parts of ketimine component B are mixed together and adjusted to an outlet viscosity of 25 s (DIN 4, 23 ° C.) with butyl acetate. The clear varnish is crocheted on glass panels with 200 .mu.m wet film thickness and dried as indicated:

Sample 1

After baking for 30 minutes at 100 ° C., the coated glass sheets are kept at room temperature for a further 24 h and then the mechanical properties of the resulting coating are tested: König pendulum hardness: 175 s petrol test ^a ': 0/0

Sample 2

After baking for 30 minutes at 60 ° C., the coated glass sheets are kept for 4 days at room temperature and the mechanical properties of the resulting coating are then checked:

Pendulum hardness according to König: 100 s petrol test ': 0/0

a: Felt platelets (0 5 cm) soaked with commercially available premium petrol are left covered on the film for 5 min. The marking (0 - no marking; 3 - clear marking) and the softening of the film (0 ■ no softening; 3 - clear softening) are then assessed. ^"

Claims

1. A curable composition containing

A) compounds with at least two activated double bonds (I) based on * -, £ -unsaturated carbonyl compounds, Λ, ß-unsaturated carboxylic acid esters or o, p-unsaturated nitrile groups,

B) Compounds which contain either at least one primary amino group (II) which is blocked with an aldehyde or ketone with no more than 10 C atoms or at least 2 groups which can be hydrolyzed to form NH groups

characterized in that either component A or component B or components A and B are based on a branched acrylate copolymer P which is soluble in organic solvents and which is obtainable by copolymerization of

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

c) 5 to 90% by weight of further ethylenically unsaturated monomers, the sum of a, b and c being 100% by weight.

2. Process for the preparation of a curable composition, the

A) Connections with at least two activated

Double bonds (I) based on ^., Ss -unsaturated carbonyl compounds,. , β-unsaturated carboxylic acid ester or>, β-unsaturated nitrile groups,

B) Compounds that are either at least one primary

Amino group, which is blocked with an aldehyde or ketone with no more than 10 C atoms or at least the 2 groups can be hydrolyzed to NH groups, and

C) usual additives, optionally catalysts, optionally

Pigments and organic solvents

contains, characterized in that first of all the soluble branched acrylate copolymer P is prepared by copolymerizing

b) 5 to 60% by weight of monomers with a functional group and c) 5 to 90% 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 which is reactive with the acrylate copolymer P, contains at least one activated double bond (I), and / or

the branched, soluble acrylate copolymer P is reacted to form B with a compound (2) which, in addition to a group which is reactive with the acrylate copolymer P, contains at least one pirmary amino group (II) which, with an aldehyde or ketone, contains not more than 10 C atoms is blocked, and A or B, preferably A, are processed in an organic solvent, optionally with pigments and conventional additives, by mixing and optionally dispersing to give a curable composition, and shortly before use the other component (B or A) is optionally added together with catalysts.

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).

4. Composition according to claim 1, characterized in that component B is 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, has at least one primary group Contains amino group (II), which is blocked with an aldehyde or ketone with not more than 10 carbon atoms.

5. Composition according to claim 3 or method according to claim 2, characterized in that the component b of the acrylate copolymer is a hydroxyl group-containing monomer and the compound (1) is a monoester of an oi, (i-unsaturated carboxylic acid.

6. A composition according to claim 3 or a method according to claim 2, characterized in that component b of the acrylate copolymer is a monomer containing hydroxyl groups and compound (1) is an ot-, ß-unsaturated carboxylic acid.

7. The composition according to claim 3 or the method according to claim 2, characterized in that the component b of the acrylate copolymer is a monomer containing hydroxyl groups and the compound (1) contains an isocyanate group in addition to group (I). Composition according to claim 3 or method according to claim 2, characterized in that the component b of the acrylate copolymer is a monomer containing hydroxyl groups and the compound (1) is an amide of an alkoxymethyl group of a, 3-unsaturated carboxylic acid or the compound (1) of the general formula

9. The composition according to claim 3 or the method according to claim 2, characterized in that the monomer b contains an epoxy group and the compound (1) has a carboxyl or amino group.

10. The composition according to claim 3 or the method according to claim 2, characterized in that the component b contains an ester function, the esterification alcohol not containing more than 6 carbon atoms, and the compound (1) in addition to the group (I) Contains OH, NH or SH group.

11. The composition according to claim 3 or the method according to claim 2, characterized in that the monomers b contain isocyanate groups and the compound (1)

5 in addition to group (I) have OH, NH, SH or COOH groups.

12. The composition according to claim 3 or the method according to claim 2, characterized in that b is an alkoxy

10 methyl group-containing amide of a (., Β-unsaturated carboxylic acid or a compound of the general formula

R 0 R ¹ ic IHI ^iD CH ₂ = CCNX-COOR '

with R = H, CH ₃

R = H, alkyl, aryl 0 R ² = alkyl

-C-, -CH-, -CH-, -CH- II II i OR OR ¹ COOR ¹

25 and the compound (1) in addition to group (I) OH-,

NH, SH or COOH groups.

13. The composition according to claim 4 or the method according to claim 2, characterized in that the Monomer¬ component b is a hydroxyl-containing monomer 0 and the compound (2) in addition to the group (II) on average 0.8 to 1.5, preferably 1 , has free isocyanate group.

14. The composition according to claim 4 or the method according to 5 claim 2, characterized in that b monomers with glycidyl groups and (2) contains an NH group in addition to group (II).

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

16. The composition according to claim 4 or method according to claim 2, characterized in that b are monomers with isocyanate groups and (2) in addition to the group (II) contains OH or NH groups.

17. The composition or method according to claim 5, characterized in that the compound (1) are esters - ~ -, ^ - ethylenically unsaturated carboxylic acids, the alcohol component of which have up to 6 carbon atoms.

18. The composition or method according to claim 7, characterized in that the compound (1) is an isocyanatoalkyl 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 H ₅ and X - (CH ₂ ) _n with n = 1-12

mean or that the compound (1) is m-isopropenyl «,« t-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 dimethyl acrylic acid.

19. Composition or method according to claim 8, characterized in that the compound (1) is selected from the group methoxymethylacrylamide,

Methoxymethyl methacrylamide, butoxymethylacrylamide, butoxymethyl methacrylamide, isobutoxymethylacrylamide, isobutoxymethyl methacrylamide, analogous amides of fumaric acid, crotonic acid and dimethylacrylic acid, glycolic acid derivatives, such as methyl acrylamide, glycolate methyl butyl acrylamyloglycolate, butyl acrylamyloglycolate.

20. Composition or method according to claim 9, characterized in that the compound (1) is selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, dimethylacrylic acid, fumaric acid, monomethyl ester, the reaction products of acid anhydrides and hydroxyalkyl esters. C, O-unsaturated acids or t-butylaminoethyl methacrylate or bisacrylamido¬ acetic acid or bis (acrylamidoethyl) amine.

21. The composition or method according to claim 10, characterized in that the compound b is selected from the group of the hydroxyalkyl esters ei, J-unsaturated carboxylic acids, such as methyl, ethyl, propyl, butyl, isobutyl , Isopropyl, hexyl esters of acrylic acid, methacrylic acid, fumaric acid, crotonic acid, dimethylacrylic acid and the aminoalkyl esters of the aforementioned c *. J3-unsaturated carboxylic acids.

22. The composition or method according to claim 11, characterized in that the monomers b are selected from the group m-isopropenyl-eJ -dimethylbenzyl-isocyanate, the isocyanatoalkyl esters e, {3-unsaturated carboxylic acids and the adducts, for example of isophorone diisocyanate on hydroxyalkyl (meth) acrylates.

23. The composition or method according to claim 12, characterized in that b is selected from the group N-alkoxymethyl (meth) acrylamide, alkoxy (meth) - acrylamidoglykolatalkylether, such as methoxymethylacrylamide, isobutoxymethylacrylamide.

24. The composition or method according to claim 13, characterized in that the reaction products of di- or polyisocyanates with the ketimine or aldimine of an alkanolamine having at least 4 carbon atoms are used as the compound (2).

25. Composition or method according to one of claims 1 to 24, characterized in that component a of the general formula

R 0 or R

CH ₂ = CCX- (CH ₂ ) _n -XCC = CH,

corresponds in which mean:

XX == OO ,, NNRR '' ,, S with R "- H, alkyl, aryl n» 2 to 8.

26. Composition or method according to one of claims 1 to 24, 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.

27. The composition or method according to any one of claims 1 to 24, characterized in that component a is a polycarboxylic acid or unsaturated monocarboxylic acid esterified with an unsaturated alcohol containing a polymerizable double bond.

28. Composition or method according to one of claims 1 to 24, characterized in that component a can be prepared by reacting a polyisocyanate with unsaturated alcohols or amines containing polymerizable double bonds.

29. Composition or method according to one of claims 1 to 24, 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 is methacrylic acid.

30. The method according to any one of claims 2 and 5 to 29, characterized in that compounds containing mercapto groups, preferably mercaptoethanol, are used as the polymerization regulator.

31. The method according to any one of claims 2 and 5 to 30, characterized in that peroxy esters and / or azo compounds are used as polymerization initiators.

32. Use of the curable composition according to one of claims 1 and 3 to 29 for automotive refinishing.

33. Use of the curable composition according to one of claims 1 and 3 to 29 as a clear coat, filler or top coat.

34. Use of the curable composition according to one of claims 1 and 3 to 29 as a basecoat containing metal pigments and / or as a clearcoat of a metallic coating.