CA1328888C - Curing component, and the use thereof - Google Patents

Abstract

Abstract of the disclosure Curing component, and the use thereof The invention relates to a curing component (A) containing active CH groups, which contains at least two groups of the formula (I) (I) or structural units of the formula (I') or (I") (I') (I") in which:

A denotes or , X and Y are identical or different and denote , CO2R1, CN, NO2, CONH2, CONR1H or CONR1R1, where the R1 radicals may be identical or different and represent a hydrocarbon radical, preferably an alkyl radical having 1 to 12 carbon atoms, which may also be interrupted by oxygen or an N-alkyl radical, with the proviso that only one of the two radicals X and Y
may represent the NO2 group;

A' denotes or , X' and Y' are identical or different and denote or

Description

~ --` 1 328888 ` HOECHST AKTIENGESELLSCHAFT HOE 87/F 295 Dr.ZR/A~

Description Curing component, and the use thereof S The curing of polyol res;ns using polyisocyanates ;s ~; kno~n. Some of these systems have proven very successful, `~ and some also have so-called cold-curing properties.

For environmental protection and industrial safety rea-' 10 sons, however, it is des;rable to have available isocyanate-free surface-coating systems ~hich, taking into account economic factors, cure as far as possible at room temperature and give high-quality coating films.

An isocyanate-free surface-coating system, based on the Michael addition, is known, for example, from German Patent 835,809. In this, substances which contain at least two methylene or methine groups activated by electron-~ithdrawing groups ~inter alia acetoacetates, acetoacetamides and cyanoacetates) are empLoyed as CH-active compounds tMichael donors). Compounds which con-tain at least two double bonds activated by an electron-~ithdrawing group ~inter a~ia esters or amides of acrylic acid and/or methacrylic acid) are used as unsaturated - 25 substances (Michael acceptors). In practice, ho~ever, relatively high temperatures are necessary for complete ; curing of the above systems.
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The same curing principle is used in EP-OS 161,679, where malonic ester group-containing oligomers or polymers func-tion as CH-active substances. At room temperature, how-ever, the crosslinking reaction aga;n proceeds relatively slo~ly here; after one day, the films still have inade-quate chemical resistance and hardness. A similar dis-advantage is exhibited by the binder system in US Patent~,408,018, uhich is likewise based on the Michael addition.

'r - 2 - t 32 8 8 8 8 An aLternative curing principle is used in the condensa-tion of silanols, which form during curing of silicon-~ containing polymers whose hydrolysis-sensitive groups on - the silicon atom react with atmospheric moisture; in this respect, cf., inter alia, EP Offenlegungsschrifte~ 50,249, 159,716 and 182,316. The relatively complex preparation of the silicone-conta;ning start;ng compounds and the dependency of the properties of the coating films on the relative atmospheric humidity are disadvantageous in this system. In addition, the polycondensation may commence, under the influence of atmospheric moisture, even before processing of the surface-coating material, which results in skin formation or in precipitation in the coating material.
'. 15 Similar problems are also exhibited by the system of EP
~ Offenlegungsschrift 34,720, which is based on an oxazoli-- dine group-containing acrylate resin, where water or atmospheric oxygen are likewise used as curing agents.
Finally, in German Offenlegungsschrift 3,541,140, a curing product made from olefinically unsaturated compounds as s binders and hydrogen-active compounds having a methanetri-monoamide structure as curing agents is described. A
disadvantage is that relatively large amounts of polyiso-cyanates, which are hazardous to health, are required for the preparation of the curing agents. In addition, the carboxamide group-containing curing agents are not in all cases perfectly soluble in the customary surface-coa~ing solvents. A further disadvantage is the great scratch - sensitivity of the films, which is probably attributable ;~ to the fact that, due to the preparation process, the curing agents still contain relatively large amounts of unreacted malonic esters, which do not react with the ole-finically unsaturated binders.

There is therefore a demand for an isocyanate-free, cold-curing system which does not have the disadvantages above and which results in cured products the propert;es of :

..

which compare well with the known isocyanates-containing systems.
~, The invention therefore relates to a curing component (A) containing active CH groups, which contains at least two groups of the formula (I) ~ X
'~ CH-A- (I) s : ,~ Y
..~
or structural units of the formula (I') or (I") t X' - CH - A' 3 (I') { X' - CH - A'~
. ..
`~` O O Y
; in which: A denotes C or C-O, the latter group being bonded to x~ 10 the CH group via the carbon atoms; X and Y are identical or .~, O
different and denote R -C, CO2Rl, CN, NO2, CONH2, CONR H or .~ CONRlRl, where the Rl radicals may be identical or different and represent an alkyl radical having 1 to 12 carbon atoms, with the : . ...
proviso that only one of the two radicals X and Y may represent ~"~, the NO2 group; A' denotes C or C-O, where the latter group is ~i bonded to the CH group via the carbon atom; X' and Y' are iden-O O l ,~ tical or different and denote C-O or C-N, with the proviso that, when A' and X' denote -COO- the radical Y' is not -CON-, the CH

. equivalent weight of the curing component (A) being from 100 to 5000 and the mean molecular weight being from 1,000 to 100,000.

; In addition, the invention relates to a process for the ~3 preparation of this curing component (A), to curable mix-tures which contain this curing component ~A), and to the use of these curable mixtures as surface-coating prepara-tions, in particular as automobile repair paints.
. S
The number of groups (I) in the curing agent according to the invention is preferably 2 to 200 and in particular 2 to 10, the larger numerical value relating to oligomeric or polymeric products and representing mean values here.
, 10 The curing component (A) preferably has the formula (II) ( ~ CH- A) R ( I I ) :~ 15 'J'" in which X, Y and A have the above meaning, R2 represents :, 2 ll the radical of a polyol R ~OH)ntA = C-0) or the radical :, O
R2 of a polycarboxylic acid R2(C02H)n(A = C) and n denotes at least two, preferably 2 to 200, in particular 2 to 10.
In the case of oligomeric or polymeric curing components, these numerical data are again mean values.
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. ~, Furthermore preferred are curing components which are ob-tained by transesterification of compounds of the formula ~^ (III) or of the formula (IV) .,. R10 C R10 ~' 30 Ch-A-R (III) l ~CH-A-R (IV) .~ X R 02C
USiR9 polyols R2(0H)n, uhere X, A and R1 have the above meaning.
The abovementioned polyo~s R2(0H)n may be polyhydric alco-hols, preferably having 2 to 12, in particular 2 to 6, carbon atoms. Examples of these are: ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4- and 2,3-butylene glycol, di-~-hydroxyethylbutanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,6-cyclohexanediol, 1,4-bis(hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxycyclo-` hexyl)propane, 2,2-bis(4-(B-hydroxyethoxy)phenyl)propane, 2-methyl-1,3-propanediol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, tris-(B-hydroxy-ethyl) isocyanurate, trimethylolethane, pentaerythritol and the hydroxyalkylation products thereof, furthermore 7,` diethylene glycol, triethylene glycol, tetraethylene gly-~;; 10 col, polyethylene glycols, dipropylene glycol, tripropy-lene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols and xylylene glycol. It is also possible to employ polyesters, which are obtained from or , using lactones, for example E-caprolactone, or hydroxy-carboxylic acids, such as, for example, hydroxypivalic acid, ~-hydroxydecanoic acid, ~-hydroxycaproic acid or thioglycol;c acid. The index n in the above formula (II) preferably represents 2 to 4 in the case of polyhydric alcohols of this type.
~; 20 The polyol may alternatively be an oligomeric or polymeric polyol compound (polyol resin) ~hose molecular ~eight Mw (weight average, determined by means of gel chromato-graphy; polystyrene standard), is usually in the range from about 309 to about 50,00û, preferably about 5,000 to '~ about 20,000. In special cases, ho~ever, the molecular ~eight ~ay be 100,000 or more. Suitable oligomers/poly-mers here are polymerization product, polycondensates or polyaddition compounds~ ~he hydroxyl number is generally 30 to 250r preferably 45 to 200 and in particular 50 to 180, mg of KOH/g. These OH group-containing compounds may optionally contain further functional groups, such as carboxyl groups.

; 35 Examples of polyols of this type are polyether polyols, polyacetal polyols, polyester amide polyols, polyamide polyols, epoxy resin polyols or the reaction products thereof uith C02, phenolic resin polyols, Polyurea poly-ols, polyurethane polyols, cellulose esters and cellulose - 6 - l 32 8 8 8 8 ether polyoLs, partially hydrolysed homopolymers and co-polymers of vinyl esters, partially acetalated polyvinyl alcohols, polycarbonate polyols, polyester polyols or acrylate res;n polyols. Polyether polyols, polyester polyols, acrylate resins and polyurethane polyols-are preferred. Polyols of this type, which may also be em-ployed in mixtures, are described, for example, in German Offenlegungsschrift 3,124,784.

Examples of polyurethane polyols are produced from the reaction of diisocyanates and polyisocyanates ~ith an excess of diols and/or polyols. Suitable isocyanates are, for example, hexamethylene diisocyanate, isophorone diiso-cyanate, toluyl diisocyanate and isocyanates formed from three moles of a diisocyanate, such as hexamethylene di-;socyanate or isophorne diisocyanate, and biurets produced from the reaction of three moles of a diisocyanate with one mole of water. Suitable polyurea polyols can be ob-- tained in a similar way by reacting diisocyanates and po~yisocyanates ~ith ecluimolar amounts of aminoalcohols, - for example ethanolamine or diethanolamine.
, . ..
. . ,:
Examples of polyester polyols are the kno~n polyconden-,~ sates made from dicarboxylic acids or polycarboxylic acids or ~he anhydrides thereof, such as phthalic anhydride, adipic acid etc., and polyols, such as ethylene glycol, ~' trimethylolpropane, glycerol etc.

Suitable polyamide polyols can be obtained in similar fashion to the polyesters by replacing the polyols, at ~` least partly, by polyamines, such as isoPhoronediamine, 'J hexamethylenediamine, diethylenetriamine etc.

Examples of polyacrylate polyols or OH group-conta;ning poLyvinyl compounds are the kno~n copolymers made from hydroxyl group-containing (meth)acrylic esters or vinyl alcohol and other vinyl compounds, such as, for example, styrene or (meth)dtrylic esters.

The polycarboxyl;c acids R2(C~2H)n above where n is pre-ferably 2 to 4 here may be of an aliphatic, cycloalipha-t;c, aromatic and/or heterocyclic nature and optionally substituted, by halogen atoms, and/or saturated. Examples , 5 ~f such carboxylic acids and der;vatives thereof ~hich may be mentioned are: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, tere-phthalic acid, isophthalic acid, trimellitic acid, pyro-mellitic acid, tetrahydrophthalic acid, hexahydrophthalic acid, di- and tetrachlorophthalic acid, endomethylene-~ tetrahydrophthalic acid and its hexachloro derivative, -~ glutaric acid, maleic acid, fumaric acid, dimeric and tri--- meric fatty acids, such as oleic acid, optionally mixed with monomeric fatty acids or cyclic monocarboxylic acids, such as benzoic acid, p-tert.-butylbenzoic acid or hexa-i hydrobenzoic acid, and furthermore the products of the react;on of the abovementioned polyols R2(0H)n ~ith cyclic carboxylic anhydrides.

- ~a The curing component (A) according to the invention is a - ~iquid of vary;ng viscosity, depending on the nature of the Polyol or polycarboxylic acid component, or a solid ~hich is substantially soluble, at least in the customary surface-activating solvents, and preferably contains less than 5X by weight, in particular less than 1% by weight, of crosslinked components. The CH equivalent weight, which is a measure of the number of groups (I) or struc-tural units tI')/~II") in ~A), is generally bet~een 100 and 5,000, preferably 200 and 2,000, and the mean molecu-30 lar weight Mw is generally between 1,000 and 100,000, preferably between 2,000 and 50,000 ~determined by gel chromatography; polystyrene standard).

It is also possible to employ mixtures of the above com-pounds as curing components tA).

uring components ~A) can be prepared by several routes.
Thus, for exa~ple, the synthesis can proceed from com-Pounds (\~) .

1 3288~8 -CH (V) y~ 2 which are acylated using chlorides of monobasic or poly-basic carboxylic acids or carboxylated using chlorofor-mates of monohydric or polyhydric alcohols or nitrated, and the products thus obtained are if appropriate, trans-esterified using polyols or transamidated using polyamines.
In the case of nitration, at least one of the two radicals X and Y must denote the -C02R1 radical, and neither of these radicals may represent an N02 group.
. ,.,~
,~
., .
Examples of compounds of the formula (V) are: dialkyl malonates of alcohols having 1 to 12, preferably 1 to 10, carbon atoms, such as dimethyl malonate, diethyl malonate, diisopropyl malonate and dioctyl malonate, the correspond-ing esters of cyanoacetic ac;d, such as, for examPle, ~`~ ethyl cyanoacetate or hexyl cyanoacetate; the correspond-ing esters of acetoacetic acid, such as ethyl acetoace-tate; diketones, such as acetylacetone; and malononitrile or malonic diamides or monoamides.

The compounds (V) are acylated in a known manner using acid chlorides of monocarboxylic acids having 1-10, pre--~¦ ferably 1 to 6 carbon atoms, or using acid chlorides of ~i polycarboxylic acids preferably having 2 to 10 carbon -~ atoms. Examples of appropriate poLycarboxylic acids are described above.
For carboxylation, the compounds (V) are reacted with - chloroformic esters of monohydric or polyhydric alcohols of the abovementioned type, such as, for example, methyl chloroformate, ethyl chloroformate or 1,6-hexanediol bis-chloroformate~
.~-i For acylation or carboxylation, the compound (V) is - initially reacted with alkal; ~etal or alkaline earth aetaL al~ox1des, preter~oly sodiu- al~oxide, potassium ~ `
1 328~88 9 _ _ alkoxides or magnesium alkoxides, such as methoxides or ethoxides, and the products are reacted with acy~ chlor-ides (R2tCOCl)m (m ~ 1-200) of monobasic or polybasic carboxylic acids or with chloroformic esters R (OCOcl)m of monohydric or polyhydric alcohols. This reaction ex-pediently proceeds in inert solvents, such as ethers and ; aLiphatic or aromatic hydrocarbons, preferably diethyl ether, tetrahydrofuran, dioxane, diethylene glycol di-methyl ether, toluene or xylene, or appropriate mixtures.
In pLace of the above alkoxides, the free metals can, less preferably, be reacted with (V).
"
The nitration can be carried out, for example, by react;ng the compounds (V) with fuming nitric ac;d or by ox;dizing ; 15 the correspond;ng nitroso compounds by methods known from the literature, for example at temperatures from 10 to 25C with or without solvent.

It is necessary to transesterify the products obtained above using polyols of the type mentioned above in order to polyfunctionalize the curing component. This trans-ester;fication, which can be omitted, for example, in the ; acylation of alcohols, is carried out, for example, by heating the acylated, carboxylated or nitrated compounds (V) with the polyols, such as polyhydric alcohols, to temperatures from B0 to 200C, preferably 100C to 160C, -. and removing the monofunctional alcohol by d;stillat;on, if appropriate under reduced pressure. The reaction usually proceeds without catalysts. However, the known ~; 30 esterification catalysts, such as metal salts of organ;c acids, for example the acetates, octanoates or naphtha-nates of tin, zinc, lead, iron, copper, chromium and cobalt, and dibutyltin oxide, may be added in amounts from 0.1 to 1.0X by weight to provide acceleration. Dibutyltin dilaurate is particularly preferred. Through a suitable choice of the weight ratio of the reaction participants in the transesterification, the formation of crosslinked esters of polyhydric alcohols can be suppressed in favor of formation of the straight-chain or branched esters ,,.

i desired. In addition, chain terminators, i.e. compounds - which react in a monofunctionaL manner under the reaction conditions, such as monoalcohols, monoamines or mono-esters, ~h;ch are preferably non-volatile, may be added to the batch for this purpose, and also to l;mit ~he " moLecular weight.
. .
; ,, i~ The transamidation using polyamines or polyamino alcohols ^ can be carried out in the same ~ay. Suitable polyamines ~, 10 are, for example, alkylenediamines, such as ethylenedia-mine and its homologs, or polyalkylenepolyamines, such as diethylenetriamine or triethylenetetramine, or cycloali-phatic polyamines, such as piperazine, or polyoxyalkylene-polyamines. Suitable polyamino alcohols are, for example, hydroxyethyldiethylenetriamine or bishydroxyethyldiethy-lenetriamine, or the products of the reaction of cyclic carbonates ~ith polyamines.
, In another me~hod of preparing the curing components - 20 according to the invention, compounds of the formula (VI) .s R 02C (VI~
,.,,.,~ CH2 X
in which R1 and X have the above meanings, are, in the ~s~ above-described ~ay, transesterified using polyols or -~ transamidated using polyamines, and these transesteri-; fication products are subsequently acylated in the manner described using chlorides of monobasic and polybasic car-~ .~
boxylic acids or carboxylated using chloroformic esters of monohydric or polyhydric alcohols or nitrated using ~, ~ nitric acid.
~ '''', P In the transesterification or transamidation of the com-35 pounds (VI) or the acylated, carboxylated or nityrated compounds (V), the reactants are normally employed in amounts such that at least one hydroxyl or amino group is transferred to (VI) or to the acylated, carboxylated or nitrated comcound (V).

.

The curing component (A) according to the invention is employed in curable mixtures together ~ith compounds (B) - ~hich contain at least t~o groups which are capable of Michael addition, i.e. groups which contain double bonds activated by at least one electron-withdrawing group (Michael acceptor). Suitable compounds (~) are described, for example, in German Patent 835,809, in US Patent 4,408,018 and in European Offenlegungsschriften 161,679 and 224,158, to which reference is made here.
The compounds (B) preferably contain at least two groups of the formuLa (VII) R3R4C = CR4-~- (VII~
in ~hich:
R3 denotes hydrogen or a hydrocarbon radical, preferably an alkyl radical, hav;ng 1 to 12, preferably 1 to 4, carbon atoms, such as the methyl, ethyl, n-propyl, ;so-propyl, n-butyl or tert.butyl group;
R4 are ;dent;cal or different and denote hydrogen, a ` 20 hydrocarbon radical, preferably an alkyl rad;cal, -having 1 to 10, preferably 1 to 4, carbon atoms, an ester group C02R1, or a -CN-, -N02-, -S02-, -CONHR -~ -CONR1R1 or -COR1 group where R1 has the above `` mean;ng; and B denotes C, C-O, C-N, ~h~re the t~o latter groups are ; bonded to the CR4 group via the carbon atom.

In the R3R4C group above, R3 and R4 preferably each represent hydrogen.
."
-~ The groups (VII) above are l;nked indirectly to one another. A suitable ;ndirect linkage here ;s, for exam-ple, a hydrocarbon radical, but preferably the rad;cal of a polyhydric alcohol R1(0H)n or of a polyvalent amine or am;no alcohol. Th;s ;ndirect l;nkage ~ay also be part of the cha-in of an oligomer and/or polymer, i.e. the groups (VII) may be present in the side chains of the oligomer or polymer or form these side chains.

In the specific embodiment, the compound (B~ has the for-mula ( V I I I ) (R3R4C = CR4-A-)mR2 (VIII) in ~hich R3, R4 and A have the meaning in the formula (VII), R2 corresponds to the meaning in the formuta (Il) and m denotes at least 2, preferably 2 to 200.

The R3R4C = CR4-A- group (VII) may be derived, for exam-ple, from a mono- or polyunsaturated mono- or dicarboxyl;c acid having 2 to 20, preferably 3 to 10, carbon atoms.

- Examples of carboxyl;c acids of this type are crotonic i,.
`~ acid, citraconic acid or the anhydride thereof, sorbic acid, fumaric acid, mesaconic acid, substituted and unsub-~' 15 stituted cinnamic acids, dihydrolevulinic acid, malonic `~ wononitrile, ~-cyanoacrylic acid, alkylidenemalonic acid, - alkylideneacetoacetic acid, preferably acrylic acid, meth-acrylic acid and/or maleic acid, or its anhydride. The possible linking of the Michael acceptor to the connecting , 20 member, such as a polymeric support, via group A, but t alternatively via the radica~ R4, can take place via ester, amide, urethane or urea groups.

-~ Corresponding to the above, the groups of the formula .~ 25 (VII) may be bonded to the radical of a polyol, a poly-awine, a polyamide or a polyiminoamide, ~here this radical ~' may also be oligomeric or polymeric.
~; ~
,'~f Suitable polyols here are in principle the same as men-,:
30 tioned above in connection ~ith the Michael donor, i.e.
polyhydric alcohols or oligomeric or polymeric polyol compounds, for example Polyether polyols, polyester poly-ols, acrylate resin polyols and polyurethane polyols.
, 35 SuitabLe amino group-containing supports (polyamines) are, for example, the abovementioned alkylenediamines and the oligomers thereof, such as ethylenediamine, propylene-diamine, butylenediamine, diethylenetriamine, tetramines and higher homologs of these amines, furthermore amino alcohols, su~h as diethanolamine or the lik~32 8~ 88 ~ The examples of compounds (B) which may be mentioned here - are: alkylglycol d;(meth)acryLate, such as as ethylene glycol diacrylates, diethylene glycol d;acrylate, propy-Lene glycol diacrylate, trimethylene glycol d;acryLate, neopentyl glycol diacrylate, 1,3-butylene glycol diacry-late, 1,4-butylene glycol diacrylate, 1,6-hexamethylene glycol diacrylate, 1,10-decamethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol tetra-acrylate, pentaerythritol triacrylate and the correspond-ing methacrylates.
;::
In addition, the acryloxy group may be bonded to polymers, for example condensation polymers, uch as polyesters, or polyaddition polymers, such as polyurethanes, polyethers or vinyl polymers, such as glycidyl (meth)acrylate copoly-mers. Examples which may be mentioned here are urethane ; acrylates, obtained by reacting polyisocyanates, such as - 20 hexamethylene diisocyanate, with hydroxyalkyl acrylates, such as hydroxyethyl acrylate, or by reacting hydroxyl group-containing polyesters, polyethers or polyacrylates with polyisocyanates and hydroxyalkyl acrylates, urethane acrylates, obtained by reacting caprolactonediol or -triol ~ith polyisocyanates and hydroxya~kyl acrylates, polyether acrylates, obtained by esterifying hydroxypolyethers using acrylic acid, polyester acrylates, obtained by esterifying hydroxypolyesters using acrylic acid, and polyacrylates, - obtained by reacting acrylic acid with vinyl polymers containing epoxide groups, for example copolymers with - glycidyl (meth)acrylate or vinyl glycidyl ether.

Mixtures of the compounds above are also possible as com-ponent (B).
The C=C equivalent ~eight of component ~B) is generally bet~een 85 and 1,800, preferably bet~een 180 and 1,200, and the molecular ~eight M~ is generally between 170 and 50,000, preferably 500 and 30,000.

The mixing ratio of the two components (A) and tB) depends on the number of available C-H-acidic hydrocarbon atoms in the curing component and on the number of unsaturated groups in the ~,~-unsaturated compounds. Since the reac-tive groups can be determined titrimetrically, precisestoichiometric mixing ratios can be produced. In general, ' the donor:acceptor group equivalent ratio is 2:1 to 1:2, '.,!~ in particular about (0.8-1.2):1 to about 1:(0.8-1.2). In - this ~ay, an adequate crosslinking density is generally achieved.

In order to accelerate the curing reaction corresponding-, ly, the curable mixtures according to the invention con-~` tain the catalysts ~hich are kno~n for the Michael !~, 15 addition, in particular Le~is bases or Bronstedt bases.
Suitable catalysts can be found, for example, in European . Offenlegungsschrift 224,158, to uhich reference is again made here.
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~'~ 20 Catalysts which may be mentioned here are, for example, sterically hindered tertiary amines, such as, for example, 1,4-diazabicyclo(2.2.2)octane (DABCO), cyclic amidines, such as, for example, 1,8-diazabicyclo(5.4.0)undec-7-ene ~ (DBU), 1,4-diazabicyclo(4.3.0)non-5-ene (DBN) inter alia, 3,:~ 25 guanidines, such as, for example, N,N,N,N-tetramethyl-guanidine, quarternary ammonium salts, such as alkyl--~ aryl- and/or benzylammonium fluorides, if appropriate in combination ~ith tetraalkoxysilanes; examples of quater-nary ammonium salts of this type which may be mentioned here are: benzyltrimethylammonium fluorides and tetra-butylammonium fluoride; in addition, the corresponding hydroxides and carbonates of quaternary ammonium salts, such as, for example, alkylbenzyldimethylammonium hydro-xide, alkyltrimethylammonium hydroxide (alkyl = C16-Cz2), benzyltrimethylammonium hydroxide and tetrabutylammonium hydroxide, may be used. The ammonium salts mentioned can be used alone or mixed or in combination ~ith tertiary aliphatic amines, such as, for example, triethylamine, N-methyldiethanolamine etc. further examples here are :

strong bases from the group comprising the metal alkoxides, such as, for example, lith;um butoxide, sodium methoxide and potassium methoxide, which can be employed with or uithout cro~n ethers.
S
~`~ A further i~portant group of catalysts is tertiary phos-; phines, such as, for example, tris-2-cyanoethylphosphine, trisdiethylaminomethylphosphine, trisdimethylaminomethyl-phosphine and trishydroxymethylphosphine, or trisphenyl-phosphine, tris-p-tolylphosphine, tris-o-anilylphosphine, phenyldi-o-anisylphosphine, diphenyl-p-anisylphosphine, diphenyl-o-anisylphosphine, diphenyl-p-dimethylaminophe-nylphosphine, methyldiphenylphosphine, methylditolylphos-phine, ethyldi-p-anisylphosphine, (diethylaminomethyl)di-phenylphosphine or ~,a-dimethylbenzyliminotris(dimethyl-amino)phosphorane, ~,~-dimethylbenzyliminomethyldiphenyL-phosphorane, t-butyliminotriphenylphosphorane, preferably ~ -dimethylbenzylimino-tri-butylphosphorane.
:
20 The amount of catalyst is generally 0.01-5Z by weight, s preferably 0.2-3~ by weight, relative to the total solids , -content of the starting material. It may be varied de-pending on the reactivity of the curing components and on the pot time and curing duration or temperature intended.
- The curable 0ixtures according to the invention exhibit pot times which vary, depending on the choice of compound -- ~A) and (8~ and on the type and quantity of the catalyst or catalyst combination, between 5 minutes and about 12 30 horus. High processing reliability is thereby ensured.

The curable mixture according to the invention may, if appropriate, contain a diluent, such as customary solvents which do not interfere with the Michael addition. The 35 catalyst may thereby be better distributed or its activity may be increased. Examples ~hich may be mentioned here are: halogenated hydrocarbons, ethers, such as diethyl ether, 1,2-dimethoxyethane, tetrahydrofuran or dioxane;
ketones, such as~ for example, methyl ethyl ketone, :
' - 16 - 1 3288~8 acetone cyclohexanone and the like; alcohols, such as methanol, ethanol, propanol, butanol and benzyl alcohol, (cyclo)aliphatic and/or aromatic hydrocarbons, such as hexane, heptane, cyclohexane, benzene, toluene, the vari-ous xylenes and aromatic solvents in the boiling range from about 150 to 180C (higher-boiling mineral oil fractions, such as (R)Solvesso). The solvents may be employed here individually or mixed.
. :, ~' 10 In addition, customary additives, such as, for example, the customary paint additives, may be present in the cur-able mixture according to the invention. Examples which may be mentioned here are: pigments (iron oxides, lead oxides, lead silicates, titanium dioxide, barium sulfate, zinc sxide, zinc sulfide, phthalocyanine complexes etc.), pigment pastes, antioxidants, (UV) stabilizers, flow-~` control agents, thickeners, defoamers and/or ~etting ~, agents, reactive thinners, fillers (talc, mica, kaolin, -' chalk, quartz powder, asbestos powder, slate po~der, : ;:
various silicas, silicates etc.), additional curing agents and addition curable compounds, and the like. Addition of these additives to the mixture may be delayed until just before processing.

In order to produce the curable mixtures according to the ; invention, components (A) and (B) and, ~here appropriate, additionally the diluent and the additives, are mixed ~ith one another. In the case of lo~-viscosity components, this can take place in the solid phase, with ~he mixture being heated to elevated temperatures if necessary. Higher-viscosity products, if the curable mixtures are not to be ^~ employed as po~der paints, are dissolved or dispersed in the diluents mentioned before mixing.

Curing of the mixtures according to the invention pro-ceeds very quickly and generally takes place at -10 to 1Q0C, preferably 0 to 80C. for example, products of good hardness are obtained after 8 to 24 hours at room temperature or after only 0.5 to 1 hour at 60C.

~,~

.~

, " . , -- 1 3288~8 The curing reaction can be carried out in one step, for example by working ~ith equivalent proportions of compo-nents ~ and (B). The pot time and the properties of ~- the product depend here on the process conditions, i.e.
on the ~yPe and quantity of the starting materials, the ~etering rate of the catalyst, the temperature program, etc. ~h~s, the elasticity of the crosslinked product can be controlled ~ithin a tolerance range, for example by means of the chain length of the oligomers and/or polymers employed for (A) and (~). Although curing is generally carried out batchwise, the scope of the inventionalso includes carrying out the mixing of the components and the performanee of the reaction continuously, for example by means of an automatic painting machine.
; As a consequence of their favorable properties - above al~ the rapid curing, even at low temperatures and even at high atmospheric humidity, and the high pendulum hard-ness, the high gloss and the good chemical resistance of the coatings - the mixtures according to the invention have a w;de var;ety of appl;cat;ons in industry, for ex-ample for the production of moldings (casting resins) for tool construction or for the production of coatings and/or intermediate coat;ngs on a ~ide variety of substrates, for example on those of an organic or inorganic nature, such as uood, ~ood fiber materials (wood sealing), tex-tiles of natural or synthetic origin, plastics, glass, ceramics, building materials, such as concrete, fiberboard, synthetic stones, but in particular on metal. In addi-t;on, the mixtures according to the invention can beemployed as components of adhesives, cements, lamination resins, synthetic resin cements and, in particular, as co~ponents of pa;nts and surface coatings for coating industrial objects, househo~d app~iances, furniture and in the bui~ding industry, such as, for example, refrigera-tors, ~ashing machines, eleGtrical appliances, ~indo~s and doors. Application can take place in a kno~n manner, such as by brushing, spraying, dipping or electrostatically.

:

A preferred field of application for the mixtures accord-- ing to the invention is in the production of automotive paints (base coats and/or top coats) and in particular of aùtomobile repair paints. In this case xylene resistance and thus si~u~taneously good resistance to premium grade gasoline is important; in addition, automobi~e repair paints should exhibit gsod curing at room temperature, and release of environmental pollutants should only be ~ow. These prerequisites are substantially fulfilled here.

In the examples below, % in each case denotes X by weight and P ;n each case denotes parts by weight.
., Exa-ples A Preparation of the curing components (A) (M;chael donor) ~' ` 1) 858.4 P of tr;ethyl methanetricarboxylate and 436.6 P
` 20 of 1,6-hexaned;ol were mixed and heated to 140C under nitrogen. At this temperature, ethanol was firstly , `A~ re~oved by d;st;llation under atmospheric pressure followed by a mixture of ethanol and triethyl methane-tricarboxylate in vacuo. A total of 362 g were dis-tilled off. 933 g of a colorless, viscous liquid having a mean molecular weight (Mw; polystyrene stan-' dard) of 70,000 and an equivalent weight of 304 g/mol ;~ remained as the residue.
: ~
2) 806.5 9 of diethylmonomethyl methanetricarboxylate and 340.9 9 of 1,4-butanediol were reacted analogously to Example 1). After removing 259 9 of volatile compo-nents by distillation, 889 9 of a pale yellow viscous ~; liquid having a mean molecular weight of 20,000 and an equ;valent weight of 427 g/mol remained.
"
3) 858 9 of triethyl methanetricarboxylate and 440 9 of trimethylolpropane were reacted at 140C analogously to Example 1). A total of 600 g of volatile components ., ~` 1 328888 were removed by distillation. A colorless, viscous Liquid having a mean molecuLar weight of 4,300 and an - equivalent weight of 295 g/mol were obtained.

4) 404 9 of diethyL acylmalonate and 231 9 of 1,6-hexane-dioL were reacted analogously to Example 1). After 101 9 of voltaile components had been removed by dis-tilLation, 534 9 of a colorless, slightly viscous Liquid having a mean molecular weight of 1,700 and an equivaLent weight of 268 g/~ol remained.

5) 404 9 of diethyl acylmalonate and 80 9 of trimethylol-propane were reacted analogously to Example 1). A
total of 158 9 of volatile components were removed by distillat;on. 326 9 of a colorless, slightly viscous - liquid having a mean molecular weight of 3,200 and an equivalent weight of 209 g/mol remained as the residue.

6) 103.31 9 of methyl diacetoacetate and 26.84 9 of tri-methylolpropane were reacted at 106C analogously to Example 1). After 60.2 9 of volatile components had been removed by distillation, 76.2 9 of a pale yellow, ~; viscous liquid having an equivalent weight of 235 remained.

.

7) 25.04 P of magnesium turnings, 25 ml of dry ethanol and 1 ml of tetrachloromethane were introduced into a Z liter four-necked flask equipped with stirrer, reflux condenser and dropping funnel, and salt formation was initiated by warming carefully. 160.17 P of diethyl maLonate, dissolved in 80 ml of ethanol, were added drop-wise at a rate such that the reaction did not become too vigorous. During the reaction time, a total of '~ 300 ml of dry diethyl ether was added in portions.
After all the malonate had been added drop~ise, the reaction mixture was kept under reflux for 2 hours , until the magnesium turnings had substantially dis-solved. 127 P of 1,6-hexanediol bischloroformate, dissolved in 100 ml of ether, were then added dropwise ` - 20 - l 328 8 88 over the course of 2 hours, and the mixture vas left to stand overnight at room temperature. The batch was hydrolysed using 60 ml of acet;c acid, dissolved in ; 300 ml of water, the organ;c phase was washed with water until neutral and dried over sodium sulfete, the ` organic solvent was removed on a rotary evaporator, and the cLear, oiLy residue was crystaLLized by rapid cooLing and trituration. 97.3 P of diethyL 1,6-hexane-dioLbismethanetricarboxyLate were obtained as a crystalLine solid of melting point 42C. The acid number was 230.

8) 287.2 P of diethyl n;tromalonate and 247.9 P of tri-!~ methyloLpropane were mixed at room temperature under nitrogen, and the mixture was sLowly heated to a maxi-mum of 140C, whereupon ethanol began to distil off.
` After S hours, the volatile components were removed at -~; a temperature of 140C in a water-pump vacuum, and a -~ total of 37.4 9 of a viscous, yellow oil having an equivalent weight of 441 9 were obtained; the mean ~; molecular ~eight was 1,646.
-- .

9) 360 P of diethyl maLonate and 50.25 P of trimethyLoL-.:-propane were mixed under nitrogen, the mixture was heated to 160C, 39 P of ethanoL were removed by dis-tiLlation over the course of 5 hours, aLl the volatile components were subsequently removed at 120C in a ~ :;
water-pump vacuum, and 179 P of a colorless oil whose mean molecular weight was 3,600 ~ere obtained. 100 P
of the reaction product obtained, dissolved in 40 P of dry ethanol, were added dropwise over the course of 2 hours to 12.52 P of magnesium turnings, 12.5 ml of dry - ethanol and 0.5 ml of tetrachloromethane, and the mix-; ture was subsequently kept under reflux for a further 3 hours until the nagnesium turnings had substantially dissolved. 52 9 of e~hyl chloroformate, dissolved in 150 ml of ether, were subsequently added dropwise over the course of 2 hours, and the mixture ~as left to react at room temperature for 2 days. After hydrolysis using water and acetic acid (5:1~ until the mixture ~as slightly acidic, the organic phase was separated off and dried over Na2S04, and the volatile components were removed in a water-pump vacuum. 202.5 9 of a carboxethylated product having an equivalent weight of 708 9 ~ere obtained.

1û) 2,090.1 9 of triethyl methanecarboxylate, 709.7 9 of 1,4-butanediol and 45û.0 9 of a polycaprolactonediol having a molecular weight of 400 g/mol were mixed, the mixture was heated at 125-135C for 7 hours under nitrogen. A total of 697.5 9 of ethanol were removed ~ by distillation. 2,552.3 9 of a colorless, viscous `~ liquid having an equivalent weight of 300 g/mol and a mean molecular weight ~Mw; polystyrene standard) of 8,300 g/mol remained as the residue.

. ., 11) 85.9 9 of triethyl methanetricarboxylate were heated - at 135-140C for 2 hours under nitreogen together with - 20 95.85 q of a polyether polyol (R Pluracol TP 440, - BASF). During this time, a total of 19.34 9 of etha-nol distilled off. 162.41 9 of a colorless, highly viscous liquid having an equivalent weight of 446 g/mol . _ ~- and a mean molecular weight (Mw; polystyrene stan-~` 25 dard) of 7,400 g/mol remained.

B Preparation of component (B) (Michael acceptor) ~`' ` ~ 1,000 P of a glycidyl group-containing acrylate resin, prepared from styrene, gLycidyl methacrylate and dimethyl ~, maleate (epoxide equivalent ueight 510), were dissolved in 680 P of xylene at 70C, and 127 P of acryl;c acid and 1 P
, of tetraethylammonium bromide were subsequently added.
u~ ~hile passing air through the mixture, stirring ~as con-tinued at 80C until the mixture had an acid number < 1.
The pale yellow solution had a solids content of 62.5Z;
C=C equivalent ~eight: 1,022.

:' - 22 - ~ 1 3 2 8 8 8 8 C Preparation of the curable mixture/coatings The amounts by weight of components (A) and (B) and of - the catalyst which are given in the table below were 5 mixed. After a spread time of 2S seconds had bee~ set using butyl acetate in accordance with 4 DIN 53211/23C, the coating material obtained was applied to glass plates .,.
, in a wet~film thickness of 100 ~m by means of an appli-cation doctor blade and cured at 60C for 30 minutes.

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Claims (22)

1. A curing component (A) containing active CH groups, which contains at least two groups of the formula (I) (I) or structural units of the formula (I') or (I") (I') (I") in which:

A denotes or , the latter group being bonded to the CH group via the carbon atom;
X and Y are identical or different and denote , CO2R1, CN, NO2, CONH2, CONR1H or CONR1R1, where the R1 radicals may be identical or different and represent an alkyl radical having 1 to 12 carbon atoms, with the proviso that only one of the two radicals X and Y may represent the NO2 group;
A' denotes or , where the latter group is bonded to the CH group via the carbon atom;

X' and Y' are identical or different and denote or , with the proviso that, when A' and X' denote -COO- the radical Y' is not -CON-, the CH equivalent weight of the curing component (A) being from 100 to 5000 and the mean molecular weight being from 1,000 to 100,000.

2. A curing component as claimed in claim 1, which has the formula (II) (II) in which X, Y and A have the above meaning, R2 represents the radical of a polyol R2(OH)n or the radical of a polycarboxylic acid R2(CO2H)n , and n denotes at least two.

3. A curing component as claimed in claim 2, wherein R2 denotes the radical of a Polyol having 2 to 12 carbon atoms, and n represents 2 to 4.

4. A curing component as claimed in claim 2, wherein R2 denotes the radical of a polyol resin R2(OH)n in which n is 2 to 200.

5. A curing component as claimed in claim 2, wherein R2 represents the radical of a polycarboxylic acid R2(CO2H)n in which n is 2 to 4.

6. A process for the preparation of a curing component as claimed in claim 1, which comprises acylating, carboxylating or nitrating a compound of the formula (V) (V) in which X and Y have the above meaning, with the pro-viso that, in the case of nitration, at least one of the two radicals X and Y must denote the -CO2R1 radi-cal and neither represents NO2, and the product thus obtained is subsequently optionally transesterified using polyols or transamidated using polyamines.

7. A process for the preparation of a curing component as claimed in claim 1, wherein a compound of the formula (VI) (VI) in which R1 and X have the above meaning, is trans-esterified using polyols or transamidated using poly-amines, and the transesterification product thus obtained is subsequently acylated, carboxylated or nitrated.

8. The process as claimed in claim 6 or 7, wherein the acylation is carried out using the chloride of a monobasic or polybasic carboxylic acid, and the car-boxylation is carried out using d chloroformate of a monohydric or polyhydric alcohol.

9. The process as claimed in claim 6 or 7, wherein the compound (V) or (VI) employed is a dialkyl malonate, an alkyl acetoacetate, an alkyl cyanoacetate or a .beta.-diketone.

10. The process as claimed in claim. 6 or 7, wherein the transesterification is carried out using a polyhydric alcohol having 2 to 12 carbon atoms.

11. A curable mixture containing a curing component (A) as claimed in claim 1 together with a compound (B) which contains at least two groups capable of Michael addition.

12. A curable mixture as claimed in claim 11, wherein the compound (B) contains at least two groups of the for-mula (VII) R3R4C = CR4-B- (VII) in which:
R3 denotes hydrogen or a hydrocarbon radical, having 1 to 12 carbon atoms;
R4 are identical or different and denote hydrogen, a hydrocarbon radical having 1 to 10 carbon atoms, an ester group CO2R1, or a -CN-, -NO2-, -SO2-, -CONHR1-, -CONR1R1 or -COR1 group where R1 has the above meaning; and B denotes , ,, where the two latter groups are bonded to the CR4 group via the carbon atom.

13. A curable mixture as claimed in claim 11 or 12, wherein the groups which are capable of Michael addition are derived from an unsaturated, at most dibasic carboxylic acid having 2 to 10 carbon atoms, and these groups are bonded to the radical of a polyol or polyamine.

14. A curable mixture as claimed in claim 13, wherein the polyol is oligomeric or polymeric and is an OH group-containing compound from the group comprising the polyesters, epoxy resins, acrylate resins and polyurethanes.

15. A curable mixture as claimed in claim 11, 12 or 14, wherein the (A):(B) equivalent ratio is 2:1 to 1:2.

16. A curable mixture as claimed in claim 11, 12 or 14, which additionally contains a catalyst from the group comprising the amides, guanidines, amidines, phosphines, quaternary ammonium fluorides or hydroxides, and alkali metal alkoxides.

17. The use of a curable mixture as claimed in claim 11, 12 or 14, in surface-coating preparations.

18. The use as claimed in claim 17 in automobile repair prints.

19. A curable mixture as claimed in claim 12, wherein R3 is an alkyl radical.

20. A curable mixture as claimed in claim 12, wherein R3 has 1 to 4 carbon atoms.

21. A curable mixture as claimed in claim 12, wherein R4 is an alkyl radical.

22. A curable mixture as claimed in claim 12, wherein R4 has 1 to 4 carbon atoms.