EP2556100A1

EP2556100A1 - Coatings that can be repaired by the application of energy

Info

Publication number: EP2556100A1
Application number: EP11712888A
Authority: EP
Inventors: Oihana Elizalde; Frederic Lucas; Angelika Maria Steinbrecher; Lydie Tuchbreiter; Axel Pfahler; Rolf Mülhaupt
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2010-04-09
Filing date: 2011-04-08
Publication date: 2013-02-13
Also published as: WO2011124710A1

Abstract

The present invention relates to coating compounds that can be repaired by the application of energy and that contain certain fatty acid esters, to thus obtained coatings that can be repaired by the application of energy, and to methods for the production thereof and to the use thereof.

Description

Through energy input reparable coatings

Description The present invention relates to energy-acceptable coating compositions containing certain fatty acid esters, coatings obtainable by energy input, as well as processes for their preparation and their use. Polyurethane based coatings are also used to heal scratches on glass. They make use of the flowability of polyurethanes in the film. Examples thereof for this US 4584229, EP 135404 A1, DE 2634816 and EP 635348 A1 called. All previously described self-healing lacquer systems according to the prior art use only a physical residual flowability of a coating after curing to heal the resulting scratches again. However, a sufficiently high flowability of the coatings requires a low crosslinking density. This leads to unsatisfactory mechanical resistance, the z. B. do not meet the requirements for automotive applications in terms of scratch resistance or chemical resistance.

A true chemical self-healing of a coating is described only in EP 355 028 A. In this case, a lower lacquer layer contains an aromatic ketone, which on UV exposure or under the influence of sunlight causes the crosslinking of lower lacquer layers and thus causes an annealing of mechanical defects by the formation of new chemical bonds , A disadvantage here is the lack of selectivity in the formation of new crosslinking points, since the crosslinking in the coating can proceed and then leads to embrittlement.

The object of the present invention is to provide reparable coatings by energy input which are at least as scratch-resistant as the coatings known hitherto in the state of the art and have a higher repairability than comparable coatings caused by energy input.

The object is achieved by coating compositions comprising as structural components (A) at least one ester which has at least two hydroxyl groups formally composed

(A1) at least one fatty acid having at least 12 carbon atoms and (A2) at least one polyol having at least three hydroxyl groups, (B) at least one optionally blocked di- or polyisocyanate, and

(C) at least one polyhydroxy compound.

The cleavage of the bond between isocyanate groups and hydroxyl groups takes place by introducing heat and / or high-energy radiation and / or by applying pressure, preferably by introducing heat and / or high-energy radiation and more preferably by introducing heat, for example thermally or by NIR. Radiation. Under the cleavage conditions, the hydroxy groups and isocyanate groups are at least partially regressed and can be rejoined. The coating material thereby becomes easier to flow in a split state than the coating, scratches can heal by running the lower-viscosity coating compound and the crosslinking compound crosslinks again by recombination of the bonds between the hydroxy groups and isocyanate groups after completion of the energy input.

In this document, the term coating composition is understood to mean the uncured composition which contains coating medium (binder) and optionally pigment and / or other typical coatings additives.

The coating is understood to mean the applied and dried and / or cured coating composition. The compounds (A) according to the invention contain on average at least 2, more preferably 2 to 20, very preferably 2 to 10, in particular 2 to 6, especially 2 to 4 and often 2 to 3 hydroxy groups.

Hydroxy groups may be present in compound (A) in amounts up to 5 mol / kg of compound (A), preferably 0.1 to 5, more preferably 0.3 to 4.5, most preferably 0.5 to 4 and especially 1 to 3 mol / kg.

The component (A1) is at least one fatty acid, for example one to five, preferably one to three, particularly preferably one to two and very particularly preferably exactly one fatty acid.

It is a preferred embodiment of the present invention that in particular natural fatty acids are used in the form of their mixtures. The fatty acid (A1) has at least 12 carbon atoms, preferably at least 14 and more preferably at least 16. As a rule, the fatty acids (A1) have up to 100 carbon atoms, preferably up to 80 and more preferably up to 60.

The compound (A1) is generally alkane, alkene, alkadiene or Alkapolyencarbonsäuren which may be straight-chain or branched, preferably straight-chain, preferably alkane or Alkencarbonsäuren, more preferably alkanecarboxylic acids.

Examples thereof are lauric acid, myristic acid, pentadecanoic acid, palmitic acid, marmoric acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, hexacosanoic acid, octacosanoic acid, triacontanoic acid, dotricosanoic acid, tritricosanic acid, tetratricosanoic acid, pentatricosanoic acid, oleic acid, linoleic acid and linolenic acid.

The compound (A2) is at least one, preferably exactly one at least trifunctional polyol, preferably with three to eight, particularly preferably with three to six and very particularly preferably with three to four hydroxy groups.

Examples of these are trimethylolbutane, trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol and isomalt.

The component (A2) may preferably also be at least partially alkoxylated, more preferably ethoxylated and / or propoxylated, most preferably ethoxylated. Per hydroxy group of the parent polyol, the degree of alkoxylation may be on average from 1 to 5, preferably from 1 to 3.

Under "ethoxylation" is the presence of groups - [- CH 2 -CH 2 -O -] -, under "propoxylation" the presence of groups - [- CH 2 -CH (CH 3) -O -] - and / or

- [- CH (CH ₃ ) -CH ₂ -O -] - understood.

This can be achieved by reacting the underlying polyols with ethylene oxide or propylene oxide. The reaction of the underlying polyols with an alkylene oxide is known per se to a person skilled in the art. Possible implementation forms can be found in Houben-Weyl, Methods of Organic Chemistry, 4th Edition, 1979, Thieme Verlag Stuttgart, Ed. Heinz Kropf, Volume 6/1 a, Part 1, pages 373-385.

Preferably, the preparation is carried out as follows: The underlying polyol is, optionally dissolved in a suitable solvent such as benzene, toluene, xylene, tetrahydrofuran, hexane, pentane or petroleum ether, at temperatures between 0 ° C and 120 ° C, preferably between 10 and 100 ° C and more preferably between 20 and 80 ° C, preferably under inert gas, such as nitrogen, submitted. For this purpose, the alkylene oxide is added continuously or in portions, optionally at a temperature of -30 ° C to 50 ° C dissolved in one of the abovementioned solvents, with thorough mixing so that the temperature of the reaction mixture between 120 and 180 ° C, preferably between 120 and 150 ° C is maintained. The reaction can take place under a pressure of up to 60 bar, preferably up to 30 bar and particularly preferably up to 10 bar.

The compounds (A) can be prepared by reacting the compounds (A1) with (A2) in the desired stoichiometric ratio, preferably acid-catalyzed and with removal of the water of reaction by means of an entraining agent.

Suitable esterification catalysts are the customary mineral acids and sulfonic acids, preferably sulfuric acid, phosphoric acid, alkylsulfonic acids (eg methanesulfonic acid, trifluoromethanesulfonic acid) and arylsulfonic acids (eg benzene, p-toluene or dodecylbenzenesulfonic acid) or mixtures thereof, but also acidic ion exchangers conceivable.

Particularly preferred are sulfuric acid, methanesulfonic acid and p-toluenesulfonic acid or mixtures thereof. They are generally used in an amount of from 0.1 to 5% by weight, based on the esterification mixture, preferably from 0.5 to 5, more preferably from 1 to 4 and very particularly preferably from 2 to 4% by weight.

Particularly suitable solvents for the azeotropic removal of the water of reaction are aliphatic, cycloaliphatic and aromatic hydrocarbons or mixtures thereof.

Preference is given to using n-pentane, n-hexane, n-heptane, cyclohexane, methylcyclohexane, benzene, toluene or xylene. Particularly preferred are cyclohexane, methylcyclohexane and toluene.

The amount used is 10 to 200% by weight, preferably 20 to 100% by weight, more preferably 30 to 100% by weight, based on the sum of alcohol and

(Meth) acrylic acid. The reaction temperature is generally 60-140 ° C, preferably 70-110 ° C, most preferably 75-100 ° C. The initial temperature is generally below 100 ° C, preferably below 90 ° C and more preferably below 80 ° C. The reaction time is usually 3 to 20 hours, preferably 5 to 15 and particularly preferably 7 to 12 hours.

However, the preparation of the compounds (A) is not essential to the invention. According to the invention, the abovementioned average functionality of hydroxyl groups of the compounds (A) is crucial. Accordingly, one or more compounds (A1) can be contained in each compound (A).

Preference is given to those compounds (A) which have a melting point of at least 40 ° C., particularly preferably at least 45 ° C. and very particularly preferably at least 50 ° C.

In addition to the compound (A), at least one further component (B) which contains at least one optionally blocked di- or polyisocyanate is present in the coating compositions according to the invention.

These may be monomers or oligomers of aromatic, aliphatic or cycloaliphatic diisocyanates, preferably of aliphatic or cycloaliphatic diisocyanates

The NCO functionality of such compounds is generally at least 1.8, and may be up to 8, preferably from 1.8 to 5 and more preferably from 2 to 4.

Suitable polyisocyanates are polyisocyanates containing isocyanurate groups, polyisocyanates containing uretinyl groups, polyisocyanates containing urethane groups or allophanate groups, polyisocyanates containing oxadiazinetrione groups or iminooxadiazinedione groups, uretonimine-modified polyisocyanates of straight-chain or branched C 4 -C 20 -alkylene diisocyanates, cycloaliphatic diisocyanates having a total of from 6 to 20 C atoms or aromatic diisocyanates having a total of 8 to 20 carbon atoms or mixtures thereof.

The diisocyanates are preferably isocyanates having 4 to 20 carbon atoms. Examples of customary diisocyanates are aliphatic diisocyanates, such as tetramethylene diisocyanate, hexamethylene diisocyanate (1,6-diisocyanatohexane), octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecylenediisocyanate, derivatives of lysine diisocyanate, trimethylhexane diisocyanate or tetramethylhexane diisocyanate, cycloaliphatic diisocyanates, such as 1, 4-, 1 , 3- or 1, 2- Diisocyanatocyclohexane, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, 1-isocyanato-3,3,5-trimethyl-5- (isocyanatomethyl) cyclohexane (isophorone diisocyanate), 1, 3 or 1, 4 Bis (isocyanatomethyl) cyclohexane or 2,4- or 2,6-diisocyanato-1-methylcyclohexane and also 3 (or 4), 8 (or 9) -bis (isocyanatomethyl) -tricyclo [5.2.1.0 ^{2 6} ] decane -lsomerengemische, and aromatic diisocyanates such as 2,4- or 2,6-toluene diisocyanate and their isomer mixtures, m- or p-xylylene diisocyanate, 2,4'- or 4,4'-diisocyanatodiphenylmethane and their isomer mixtures, 1, 3 or 1 , 4-phenylenediisocyanate, 1-chloro-2,4-phenylenediisocyanate, 1,5-naphthylenediisocyanate, diphenyl-4,4'-diisocyanate, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 3-methyldi-phenylmethane 4,4'-diisocyanate, tetramethylxylylene diisocyanate, 1,4-diisocyanatobenzene or diphenyl ether-4,4'-diisocyanate.

There may also be mixtures of said diisocyanates.

There are also higher isocyanates with an average of more than 2 isocyanate groups in consideration. Triisocyanates such as triisocyanatononane, 2,4,6-triisocyanatotoluene, triphenylmethane triisocyanate or 2,4,4'-triisocyanato-diphenyl ether or the mixtures of di-, tri- and higher polyisocyanates which are suitable for example by phosgenation of corresponding aniline / formaldehyde are suitable for this purpose - Be obtained condensates and represent methylene bridges Polyphenylpolyiso- cyanate.

The usable di- and polyisocyanates preferably have a content of isocyanate groups (calculated as NCO, molecular weight = 42) of 10 to 60% by weight, based on the diisocyanate and polyisocyanate (mixture), preferably 15 to 60% by weight and particularly preferably 20 to 55 wt%.

Preference is given to aliphatic or cycloaliphatic, in the context of this document as (cyclo) aliphatically summarized, di- and polyisocyanates, e.g. the abovementioned aliphatic or cycloaliphatic diisocyanates, or mixtures thereof.

Particularly preferred are hexamethylene diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate and 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane, very particularly preferred are isophorone diisocyanate and hexamethylene diisocyanate, particularly preferably hexamethylene diisocyanate.

Isophorone diisocyanate is usually present as a mixture, namely the cis and trans isomers, usually in the ratio of about 60:40 to 80:20 (w / w), preferably in the ratio of about 70:30 to 75:25 and most preferably in the ratio of about 75:25.

Dicyclohexylmethane-4,4'-diisocyanate may also be present as a mixture of the different cis and trans isomers. Aromatic isocyanates are those containing at least one aromatic ring system. Cycloaliphatic isocyanates are those which contain at least one cycloaliphatic ring system.

Aliphatic isocyanates are those which contain exclusively straight or branched chains, ie acyclic compounds.

For the present invention, both such di- and polyisocyanates can be used, which are obtained by phosgenation of the corresponding amines, as well as those which without the use of phosgene, d. H. after phosgene-free process, are produced. For example, EP-A-0 126 299 (USP 4 596 678), EP-A-126 300 (USP 4 596 679) and EP-A-355 443 (USP 5 087 739) disclose (cyclo) aliphatic diisocyanates, eg such as 1, 6-hexamethylene diisocyanate (HDI), isomeric aliphatic diisocyanates having 6 carbon atoms in the alkylene radical, 4,4'- or 2,4'-di (isocyanatocyclohexyl) methane and 1-isocyanato-3-isocyanato-methyl-3,5, 5-trimethylcyclohexane (isophorone diisocyanate or IPDI) are prepared by reacting the (cyclo) aliphatic diamines with, for example, urea and alcohols to give (cyclo) aliphatic biscarbamic acid esters and their thermal cleavage into the corresponding diisocyanates and alcohols. The synthesis is usually carried out continuously in a cyclic process and optionally in the presence of N-unsubstituted carbamic acid esters, dialkyl carbonates and other by-products recycled from the reaction process. Di- or polyisocyanates obtained in this way generally have a very low or even non-measurable proportion of chlorinated compounds, which leads to favorable color numbers of the products.

In one embodiment of the present invention, the di- and polyisocyanates (B) have a total hydrolyzable chlorine content of less than 200 ppm, preferably less than 120 ppm, more preferably less than 80 ppm, most preferably less than 50 ppm , in particular less than 15 ppm and especially less than 10 ppm. This can be measured, for example, by ASTM D4663-98. However, it is of course also possible to use diisocyanates and polyisocyanates (B) with a higher chlorine content.

Further to mention are

1) isocyanurate-containing polyisocyanates of aromatic, aliphatic see and / or cycloaliphatic diisocyanates. Particular preference is given here to the corresponding aliphatic and / or cycloaliphatic isocyanato-isocyanurates and in particular those based on hexamethylene diisocyanate and isophorone diisocyanate. The isocyanurates present are, in particular, trisisocyanatoalkyl or trisisocyanatocycloalkyl isocyanurates, which are cyclic trimers of the diisocyanates, or mixtures with their higher homologues containing more than one isocyanurate ring. The isocyanato-isocyanurates generally have an NCO content of 10 to 30 wt .-%, in particular 15 to 25 wt .-% and an average NCO functionality of 2.6 to 8.

Uretdione diisocyanates having aromatic, aliphatic and / or cycloaliphatic bonded isocyanate groups, preferably aliphatically and / or cycloaliphatically bonded and in particular those derived from hexamethylene diisocyanate or isophorone diisocyanate. Uretdione diisocyanates are cyclic dimerization products of diisocyanates.

The uretdione diisocyanates can be used as the sole component or in a mixture with other polyisocyanates, in particular those mentioned under 1).

Biuret group-containing polyisocyanates having aromatic, cycloaliphatic or aliphatic bound, preferably cycloaliphatic or aliphatic bound isocyanate groups, in particular tris (6-isocyanatohexyl) biuret or mixtures thereof with its higher homologs. These biuret polyisocyanates generally have an NCO content of 18 to 22 wt .-% and an average NCO functionality of 2.8 to 4.5.

Urethane and / or allophanate groups containing polyisocyanates having aromatically, aliphatically or cycloaliphatically bonded, preferably aliphatically or cycloaliphatically bonded isocyanate groups, such as those by reacting excess amounts of hexamethylene diisocyanate or isophorone diisocyanate with monohydric or polyhydric alcohols such as methanol, ethanol, etc. -Propanol, n-propanol, n-butanol, / so-butanol, se / butanol, tert-butanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-dodecanol (lauryl alcohol), 2-ethylhexanol, n-pentanol, stearyl alcohol, cetyl alcohol, lauryl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 1,3-propanediol monomethyl ether, cyclopentanol, cyclohexanol, cyclooctanol, cyclododecanol, trimethylolpropane, neopentyl glycol, pentaerythritol, 1,4-butanediol, 1, 6-hexanediol, 1, 3-propanediol, 2-ethyl-1, 3-propanediol, 2-methyl-1, 3-propanediol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, glycerol, 1,2-dihydroxypropane, 2,2-dimethyl-1,2-ethanediol, 1,2-butanediol, 1,4-butanediol, 3-methylpentan-1, 5-diol, 2- Ethylhexane-1,3-diol, 2,4-diethyloctane-1,3-diol, neopentyl glycol hydroxypivalate, ditrimethylolpropane, dipentaerythritol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2 -, 1, 3 and 1, 4-cyclohexanedimethanol, 1, 2, 1, 3 or 1, 4-cyclohexanediol or mixtures thereof can be. These urethane and / or allophanate-containing polyisocyanates generally have an NCO content of 12 to 20 wt .-% and an average NCO functionality of 2.5 to 4.5. 5) oxadiazinetrione-containing polyisocyanates, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such oxadiazinetrione-containing polyisocyanates are accessible from diisocyanate and carbon dioxide. 6) polyisocyanates containing iminooxadiazinedione groups, preferably derived from hexamethylene diisocyanate or isophorone diisocyanate. Such iminooxadiazine-dione-containing polyisocyanates can be prepared from diisocyanates by means of special catalysts. 7) Uretonimine-modified polyisocyanates.

8) carbodiimide-modified polyisocyanates.

9) Hyperbranched polyisocyanates, as are known, for example, from DE-A1 10013186 or DE-A1 10013187.

10) polyurethane-polyisocyanate prepolymers, of di- and / or polyisocyanates with alcohols. 1 1) polyurea-polyisocyanate prepolymers.

The polyisocyanates 1) to 1 1) can be used in admixture, optionally also in admixture with diisocyanates. The di- and polyisocyanates (B) may also be present at least partially in blocked form.

Such isocyanate blocking groups are described in D.A. Wieks, Z.W. Wieks, Progress in Organic Coatings, 36, 148-172 (1999), 41, 1-83 (2001) and 43, 131-140 (2001).

This is particularly preferred when the coating compositions according to the invention are to be used as one-component. Preferred compounds (B) are the urethanes, biurets and isocyanurates, particularly preferably the isocyanurates of 1,6-hexamethylene diisocyanate (HDI) or 1-isocyanato. 3-isocyanato-methyl-3,5,5-trimethyl-cyclohexane, most preferably from 1,6-hexamethylene diisocyanate.

As a result of the preparation, polyisocyanates (B) may still have a small proportion of the monomeric diisocyanate on which they are based, for example up to 5

% By weight, more preferably up to 3% by weight, most preferably up to 2, in particular up to 1, especially up to 0.5 and even up to 0.25% by weight.

Furthermore, the coating compositions according to the invention also contain at least one binder (C) and optionally paint-typical additives (D) and optionally pigments and / or fillers (E).

The binders (C) may be, for example, polyacrylate polyols, polyester polyols, polyether polyols, polyurethane polyols; polyurea; Polyester polyacrylate polyols; polyester polyurethane polyols; Polyurethane polyacrylate polyols, polyurethane modified alkyd resins; Fatty acid-modified polyester polyurethane polyols, copolymers with allyl ethers, graft polymers of the substance groups mentioned with e.g. different glass transition temperatures, as well as mixtures of said binders act. Preference is given to polyacrylate polyols, polyester polyols and polyurethane polyols.

Preferred OH numbers, measured according to DIN 53240-2 (potentiometric), are 40-350 mg KOH / g solid resin for polyester, preferably 80-180 mg KOH / g solid resin, and 15-250 mg KOH / g solid resin for polyacrylatols 80-160 mg KOH / g.

In addition, the binders may have an acid number according to DIN EN ISO 3682 (potentiometric) to 200 mg KOH / g, preferably up to 150 and particularly preferably up to 100 mg KOH / g. Particularly preferred binders (C) are polyacrylate polyols and polyesterols.

Polyacrylate polyols preferably have a molecular weight M _n of at least 500, more preferably at least 1200 g / mol. The molecular weight M _n can in principle be infinite upwards, preferably up to 50,000, more preferably up to 20,000 g / mol, very particularly preferably up to 10,000 g / mol and in particular up to 5,000 g / mol.

The hydroxy-functional monomers (see below) are used in such amounts in the copolymerization that the above-mentioned hydroxyl numbers of the polymers result, which generally correspond to a hydroxyl group content of the polymers from 0.5 to 8, preferably 1 to 5 wt .-% , These are hydroxyl-containing copolymers of at least one hydroxyl-containing (meth) acrylate with at least one further polymerizable comonomer selected from the group consisting of

(Meth) acrylic acid alkyl esters, vinyl aromatics, α, ß-unsaturated carboxylic acids and other monomers.

As (meth) acrylic acid alkyl esters may be mentioned e.g. C 1 -C 20 -alkyl (meth) acrylates, vinylaromatics are those having up to 20 carbon atoms, α, β-unsaturated carboxylic acids also include their anhydrides and other monomers are, for example, vinyl esters of carboxylic acids containing up to 20 carbon atoms, ethylenically unsaturated nitriles , Vinyl ethers of alcohols containing 1 to 10 carbon atoms and, less preferably, aliphatic hydrocarbons having 2 to 8 carbon atoms and 1 or 2 double bonds.

Preferred (meth) acrylic acid alkyl esters are those having a C 1 -C 10 -alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.

In particular, mixtures of (meth) acrylic acid alkyl esters are also suitable.

Vinyl esters of carboxylic acids having 1 to 20 carbon atoms are e.g. Vinyl laurate, vinyl stearate, vinyl propionate and vinyl acetate. α, β-Unsaturated carboxylic acids and their anhydrides can be, for example, acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid, maleic acid or maleic anhydride, preferably acrylic acid.

As hydroxy-functional monomers are monoesters of α, β-unsaturated carboxylic acids, such as acrylic acid, methacrylic acid (referred to in this document as "(meth) acrylic acid"), mentioned with di- or polyols, preferably 2 to 20 carbon atoms and at least two Hydroxy groups, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,1-dimethyl-1,2-ethanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, tripropylene glycol, 1, 4-butanediol, 1,5-pentanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1, 6-hexanediol, 2-methyl-1, 5-pentanediol, 2-ethyl-1,4-butanediol, 2-ethyl-1,3-hexanediol, 2,4-diethyl-octane-1,3-diol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3 and 1, 4-bis (hydroxymethyl) cyclohexane, 1, 2, 1, 3 or 1, 4-cyclohexanediol, glycerol, trimethylololethane, trimethylolprop trimethylolbutane, pentaerythritol, ditrimethylolpropane, di-pentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (ribitol), arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol, isomalt, poly-THF with a molecular weight between 162 and 4500, preferably 250 to 2000, poly-1, 3-propanediol or polypropylene glycol having a molecular weight between 134 and 2000 or polyethylene glycol having a molecular weight between 238 and 2000 be. Preference is given to 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- or 3-hydroxypropyl acrylate, 1,4-butanediol monoacrylate or 3- (acryloyloxy) -2-hydroxypropyl acrylate and particularly preferably 2-hydroxyethyl acrylate and / or 2-hydroxyethyl methacrylate.

As vinyl aromatic compounds are e.g. Vinyltoluene, α-butylstyrene, a-methylstyrene, 4-n-butyl-styrene, 4-n-decylstyrene and preferably styrene into consideration. Examples of nitriles are acrylonitrile and methacrylonitrile.

Suitable vinyl ethers are e.g. Vinyl methyl ether, vinyl isobutyl ether, vinyl hexyl ether and vinyl octyl ether. As non-aromatic hydrocarbons having 2 to 8 carbon atoms and one or two olefinic double bonds may be mentioned butadiene, isoprene, and ethylene, propylene and isobutylene.

Furthermore, N-vinylformamide, N-vinylpyrrolidone and N-vinylcaprolactam can be used, furthermore, ethylenically unsaturated acids, in particular carboxylic acids, acid anhydrides or acid amides, and also vinylimidazole. Epoxide group-containing comonomers such as e.g. Glycidyl acrylate or methacrylate or monomers such as N-methoxymethylacrylamide or -meth-acrylamide can be used in small amounts.

Preference is given to esters of acrylic acid or of methacrylic acid having 1 to 18, preferably 1 to 8, carbon atoms in the alcohol radical, such as e.g. Methyl acrylate. Ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-stearyl acrylate, methacrylates corresponding to these acrylates, styrene, alkyl-substituted styrenes, acrylonitrile, methacrylonitrile, vinyl acetate or vinyl stearate or any desired mixtures of such monomers.

The monomers carrying hydroxyl groups are used in the copolymerization of the hydroxyl-bearing (meth) acrylates in admixture with other polymerizable, preferably free-radically polymerizable monomers, preferably those which contain more than 50% by weight of C1-C20-, preferably Cr to C 4 -alkyl (meth) acrylate, (meth) acrylic acid, vinylaromatics having up to 20 C atoms, vinyl esters of carboxylic acids containing up to 20 C atoms, vinyl halides, non-aromatic hydrocarbons having 4 to 8 C atoms and 1 or 2 Double bonds, unsaturated nitriles and mixtures thereof exist. Particularly preferred are the polymers which in addition to the hydroxyl-bearing monomers to more than 60% by weight of C1-C10 alkyl (meth) acrylates, styrene and its derivatives or mixtures thereof. The preparation of the polymers can be carried out by polymerization by conventional methods. Preferably, the preparation of the polymers is carried out in an emulsion or in organic solution. Possible are continuous or discontinuous polymerization processes. Of the batch processes, the batch process and the feed process should be mentioned, the latter being preferred. In the feed process, the solvent is introduced alone or with part of the monomer mixture, heated to the polymerization temperature, the polymerization in the case of a monomer master initiated radically and the remaining monomer mixture together with an initiator mixture in the course of 1 to 10 hours, preferably 3 to 6 Hours, dosed. Optionally, it is subsequently subsequently activated in order to carry out the polymerization up to a conversion of at least 99%.

Examples of suitable solvents are aromatics such as solvent naphtha, benzene, toluene, xylene, chlorobenzene, esters such as ethyl acetate, butyl acetate, methyl glycol acetate, ethyl glycol acetate, methoxypropyl acetate, ethers such as butylglycol, tetrahydrofuran, dioxane, ethyl glycol ethers, ketones such as acetone, methyl ethyl ketone, halogen-containing Solvents such as methylene chloride or trichloromonofluoroethane into consideration. Further binders (C) are e.g. Polyester polyols, as obtainable by condensation of polycarboxylic acids, in particular dicarboxylic acids with polyols, in particular diols. In order to ensure a functionality of the polyesterpolyol which is suitable for the polymerization, triols, tetrols, etc., as well as trifurates, etc. are also used in some cases.

Polyester polyols are e.g. from Ullmann's Encyclopedia of Industrial Chemistry, 4th Edition, Volume 19, pp. 62-65. Preference is given to using polyesterpolyols which are obtained by reacting dihydric alcohols with dibasic carboxylic acids. Instead of the free polycarboxylic acids, it is also possible to use the corresponding polycarboxylic acid anhydrides or corresponding polycarboxylic acid esters of lower alcohols or mixtures thereof to prepare the polyesterpolyols. The polycarboxylic acids may be aliphatic, cycloaliphatic, aromatic or heterocyclic and optionally, e.g. by halogen atoms, substituted and / or unsaturated. Examples include:

Oxalic, maleic, fumaric, succinic, glutaric, adipic, sebacic, dodecanedioic, o-phthalic, isophthalic, terephthalic, trimellitic, azelaic, 1,4-cyclohexanedicarboxylic or tetrahydrophthalic, hydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetra- Hydrophthalic anhydride, glutaric anhydride, maleic anhydride, dimer fatty acids, their isomers and hydrogenation products and esterifiable derivatives such as anhydrides or dialkyl esters, for example C 1 -C 4 -alkyl esters, preferably methyl, ethyl or n-butyl esters, of the acids mentioned are used. Preference is given to dicarboxylic acids of the general formula HOOC- (CH 2) _y -COOH, where y is a number from 1 to 20, preferably an even number from 2 to 20, particularly preferably succinic acid, adipic acid, sebacic acid and dodecanedicarboxylic acid.

Suitable polyhydric alcohols for the preparation of the polyesterols 1, 2-propanediol, ethylene glycol, 2,2-dimethyl-1, 2-ethanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 3-methylpentane-1, 5-diol, 2-ethylhexane-1, 3-diol, 2,4-diethyloctane-1,3-diol, 1,6-hexanediol, poly-THF having a molecular weight between 162 and 4500, preferably 250 to 2000, poly-1,3-propanediol having a molecular weight between 134 and 1 178, poly-1,2-propanediol having a molecular weight between 134 and 898, polyethylene glycol having a molecular weight between 106 and 458, Neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, 2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, 2,2-bis (4-hydroxycyclohexyl) propane, 1, 1, 1, 2, 1, 3- and 1, 4-cyclohexanedimethanol, 1, 2-, 1, 3- or 1, 4-cyclohexanediol, trimethylolbutane, trimethylolpropane, trimethylolethane, neopentyl glycol, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, Threit , Erythritol, adonite (ribitol), Arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol or isomalt, which may optionally be alkoxylated as described above.

Alcohols of the general formula HO- (CH 2) x -OH are preferred, where x is a number from 1 to 20, preferably an even number from 2 to 20. Preferred are ethylene glycol, butane-1, 4-diol, hexane-1, 6-diol, octane-1, 8-diol and dodecane-1, 12-diol. Further preferred is neopentyl glycol.

Also contemplated are polycarbonate diols, e.g. can be obtained by reacting phosgene with an excess of the mentioned as structural components for the polyester polyols low molecular weight alcohols.

Also suitable are lactone-based polyesterdiols, which are homopolymers or copolymers of lactones, preferably terminal hydroxyl-containing addition products of lactones onto suitable difunctional starter molecules. Preferred lactones are those which are derived from compounds of the general formula HO- (CH 2) _z -COOH, where z is a number from 1 to 20 and an H atom of a methylene unit is also denoted by a d- to C ₄ - Alkyl radical may be substituted. Examples are ε-caprolactone, β-propiolactone, gamma-butyrolactone and / or methyl-e-caprolactone, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid or pivolactone, and mixtures thereof. Suitable starter components are, for example, the low molecular weight dihydric alcohols mentioned above as the synthesis component for the polyesterpolyols. The corresponding polymers of ε-caprolactone are especially preferred. Lower polyester diols or polyether diols can also be used as starters for the preparation of the lactone polymers. Instead of the polymers of lactones, it is also possible to use the corresponding, chemically equivalent polycondensates of the hydroxycarboxylic acids corresponding to the lactones.

In polyurethane paints, molecular weights M _{n of} the polyesters of 800-4000 g / mol are usual, the polyesters used here are not limited thereto.

Also suitable as binders are polyetherols which are prepared by addition of ethylene oxide, propylene oxide and / or butylene oxide, preferably ethylene oxide and / or propylene oxide and particularly preferably ethylene oxide, to H-active components. Likewise, polycondensates of butanediol are suitable. In polyurethane coatings, molecular weights of the polyethers of 500-2000 g / mol are customary, with the polyethers used here not being restricted thereto.

The polymers can be at least partially replaced by so-called reactive diluents. These may be blocked secondary or primary amines (aldimines and Ketime) or compounds having sterically hindered and / or electron-poor secondary amino groups, for example aspartic acid esters according to EP 403921 or WO 2007/39133.

As further paint typical additives (D), for example, antioxidants, stabilizers, activators (accelerators), antistatic agents, flame retardants, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, plasticizers or chelating agents can be used.

Suitable thickeners besides free-radically (co) polymerized (co) polymers, customary organic and inorganic thickeners such as hydroxymethylcellulose or bentonite.

As chelating agents, e.g. Ethylenediaminetic acid and its salts and ß-di-ketones are used.

Suitable fillers include silicates, e.g. Example by hydrolysis of silicon tetrachloride available silicates such as Aerosil® the Fa. Degussa, silica, talc, aluminum silicates, magnesium silicates, calcium carbonate, etc.

Suitable stabilizers include typical UV absorbers such as oxanilides, triazines and benzotriazole (the latter available as Tinuvin® grades from Ciba Specialty Chemicals) and benzophenones. These may be used alone or together with suitable radical scavengers, for example sterically hindered amines such as 2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butylpiperidine or derivatives thereof, e.g. For example, bis (2,2,6,6-tetra-methyl-4-piperidyl) sebacinate can be used. Stabilizers are usually used in amounts of 0.1 to 5.0 wt .-%, based on the solid components contained in the preparation.

The additives (D), insofar as they are solids, preferably have a particle size of less than 100 μm and more preferably less than 50 μm.

In a particular embodiment, the additives (D), insofar as they are solids, preferably have a particle size of 1 to 1000 nm, particularly preferably 1 to 100 nm, very particularly preferably 5 to 50 nm and in particular 5 to 25 nm.

Such particles may be constituted as described in EP 1204701 B1, paragraphs [0032] to [0059], which is herewith part of the disclosure of this document.

The particles may be uniformly or non-uniformly distributed within the finished coating. In the case of an uneven distribution, the particles are preferably present on the surface of the coating in a higher concentration than in the interior of the coating.

Furthermore, the coating compositions may contain pigments, dyes and / or fillers (E).

Pigments are according to CD Römpp Chemie Lexikon - Version 1 .0, Stuttgart / New York: Georg Thieme Verlag 1995 with reference to DIN 55943 particulate "in the application medium practically insoluble, inorganic or organic, colored or achromatic colorants". This distinguishes pigments from soluble dyes.

In this case, practically insoluble means a solubility at 25 ° C. of less than 1 g / 1000 g of application medium, preferably less than 0.5, particularly preferably less than 0.25, very particularly preferably less than 0.1 and in particular less than 0.05 g / 1000 g application medium.

Examples of pigments include any systems of absorption and / or effect pigments, preferably absorption pigments. The number and selection of the pigment components are not subject to any restrictions. They can be adapted to the particular requirements, for example the desired color impression, as desired.

Effect pigments are to be understood as meaning all pigments which have a platelet-like structure and impart special decorative color effects to a surface coating. The effect pigments are, for example, all effect pigments which can usually be used in vehicle and industrial coating. Examples of such effect pigments are pure metal pigments; such as aluminum, iron or copper pigments; Interference pigments, such as z, B. titanium dioxide coated mica, iron oxide coated mica, mixed oxide coated mica (eg with titanium dioxide and Fe2O3 or titanium dioxide and O2O3), metal oxide coated aluminum, or liquid crystal pigments.

The coloring absorption pigments are, for example, customary organic or inorganic absorption pigments which can be used in the coatings industry. Examples of organic absorption pigments are azo pigments, phthalocyanine, quinacridone and pyrrolopyrrole pigments. Examples of inorganic absorption pigments are iron oxide pigments and carbon black.

Furthermore, titanium dioxide is to be mentioned as a pigment. Examples of pigments are listed in WO 97/08255, p. 8, Z. 11 to p. 11, Z. 16, which is hereby part of the disclosure of this document.

Typically, the coating compositions of the invention are composed as follows:

(A) from 0.1 to 20% by weight, preferably from 1 to 10% by weight,

(B) from 20 to 50% by weight, preferably from 30 to 40% by weight,

(C) from 20 to 50% by weight, preferably from 30 to 40% by weight,

(D) from 0 to 5% by weight, preferably from 0.1 to 5% by weight,

(E) from 0 to 60% by weight, preferably from 0.1 to 40% by weight, with the proviso that the sum always gives 100% by weight.

The molar ratio of optionally blocked isocyanate groups in (B) to isocyanate group-reactive groups in (A) and (C) in total is generally 8: 1 to 1: 8, preferably 5: 1 to 1: 5, especially preferably 2: 1 to 1: 2 and most preferably 1, 5: 1 to 1: 1, 5.

The proportion of hydroxy groups in the compound (A) to the sum of the hydroxyl groups in the compounds (A) and (C) is generally up to 20 mol%, preferably up to 15 mol% and particularly preferably up to 10 mol %.

The preparation of the coating compositions of the invention comprising at least the components (A), (B) and (C) is carried out by mixing these components with each other. It may also be preferred to incorporate component (A) into component (B), followed by mixing with component (C), or first to mix components (A) and (C) with each other and then to mix with the component (B). component (A). It would also be conceivable to first mix (B) and (C) and then (A) to interfere.

It is a particular embodiment, first to mix the components (A) and (B) and to allow at elevated temperature optionally react at least partially in the presence of a catalyst. Subsequently, it is mixed with component (B) and optionally other coating constituents and the coating composition is applied to the substrate. In this way one obtains a substantially uniform distribution of the component (A) in the coating (see below).

In a preferred embodiment, the component (A) is mixed at a temperature above the ambient temperature with the other components, for example at 30 to 80 ° C, preferably 40 to 60 ° C. Particularly preferably, (A) is mixed in the form of a melt with the other components. It is also conceivable to mix component (A) dissolved in a solvent with the other components.

The coating compositions according to the invention can be both one-component and two-component. Two-component means that the components (B) and (C) and optionally other coating constituents are mixed together only relatively shortly before the application and then essentially react with one another after application to the substrate. Mixing usually takes place in the case of two-component paints within a period of not more than 12 hours, preferably not more than 10, more preferably not more than 9, very preferably not more than 7, in particular not more than 5 and especially not more than 3 hours before application to the substrate.

In contrast, one-component (1 K) coating compositions can be mixed together longer before application.

The coatings obtained with the coating compositions according to the invention generally have a glass transition temperature T _g above -30, preferably above -10 ° C. The upper limit is usually at glass transition temperatures T _g of not more than 120, preferably not more than 100 ° C (according to the DSC method (Differential Scanning Calorimetry) according to ASTM 3418/82).

In a preferred embodiment, component (A) forms crystalline phases in the coating with a diameter of up to 1000 nm, preferably up to 800 nm, more preferably up to 600 nm, very particularly preferably up to 400 nm and in particular up to 250 nm. The phases usually have a diameter (measured at the widest point) of at least 20 nm, preferably at least 50 nm and very particularly preferably at least 100 nm.

The crystalline phases in the coating may be substantially evenly distributed, they may substantially form a layer on the surface of the coating, or they may have a higher concentration at the surface than inside the coating. Determination of the diameter of the crystalline phases and definition of the concentration profile are carried out as described in EP 1204701 B1.

The arrangement of the crystalline phases in the coating depends strongly on the properties of the components (A), (B) and (C).

A general rule is that hydrophobic, ie long-chain fatty acids (A1) mostly cause a uniform distribution of component (A) in the coating, whereas hydrophilic, ie short-chain fatty acids (A1) cause an increase in concentration of component (A) cause the surface.

However, if a particularly hydrophilic polyhydroxy compound (C) is used, this increase in concentration towards the surface can be at least partially compensated.

For repair (self-healing) of the coatings according to the invention and cured coatings are the coatings for a period of at least 10 minutes, preferably at least 15 minutes, preferably at least 20 minutes, more preferably at least 30, most preferably at least 45 and in particular at least 60 min heated to a temperature which is at least 25, preferably at least 30 and more preferably at least 35 ° C above the glass transition temperature of the coating.

Such heating can be carried out by treatment at a corresponding temperature (for example in an oven or belt furnace) or can additionally or exclusively also be carried out by heating with NIR radiation, in which case NIR radiation is electromagnetic radiation in the wavelength range from 760 nm to 2.5 μηη, preferably from 900 to 1500 nm is designated.

The coating compositions according to the invention can be used in particular as primers, fillers, pigmented topcoats and clearcoats in the field of industrial, in particular aircraft or large vehicle painting, wood, automotive, in particular OEM or automotive refinish, or decoration. The compounds (A) lead in the coating compositions of the invention by their meltability to a self-healing effect in the coatings.

Another object of the present invention is the use of compounds fertilize (A) as a reactant with di- and polyisocyanates and the reaction products thus obtained. The advantage of such reaction products is that they lead to self-healing of the coatings in two-component polyurethane coatings. Ppm and percentages used in this specification, unless otherwise indicated, are by weight percent and ppm.

The following examples are intended to illustrate but not to limit the invention. Examples

Fatty acid (A1):

Refined, very hard montan wax (fossil plant wax), consisting

from long-chain fatty acids (C16-C36) with an acid number of 125 and a molecular weight of 600 g / mol. (Waradur® LS from Völpker Spezialprodukte GmbH)

Polyol (A2):

Hexafunctional polypropylene oxide having a OH number of 490 (according to DIN 53240) and a molecular weight of 570 g / mol started on sorbitol and prepared by potassium hydroxide catalysis.

Polyisocyanate (B1):

HDI isocyanurate with an NCO content of 22.2% and a viscosity of 2800 mPa.s at 23 ° C (Basonat® HI 100 BASF SE). Polyisocyanate (B2):

IPDI isocyanurate, 70% dissolved in butyl acetate with an NCO content of 12.1% and a Viskosiät of 600 mPa.s at 23 ° C (Vestanat® T1890 B Evonik).

Polyacrylate (C):

Macrynal® SM 636/70 BAC with an OH number of 135 mg KOH / g from Cytec. Waxy production (A):

8.0 g of the polyol A2 were mixed with 15.0 g of fatty acid A1 at 130 ° C and added 50 mg of dibutyltin dilaurate. The reaction was carried out under argon atmosphere at 170 ° C for 6 hours. This resulted in the formation of water or alcohol under redu- ciert pressure (500 mbar) removed from the reaction mixture. Subsequently, the product was precipitated in methanol and dried under vacuum.

The polyol-modified crystalline wax A (Example 1 and Example 2) and the wax (A2 - Comparison 2) were dissolved in the paint formulation at 60 ° C and the resulting films were applied to a glass substrate as follows:

The polyurethane coatings were applied to glass plates (100 mm × 150 mm) with a film-drawing bar having a gap width of 200 μm. Thus, homogeneous paint films with different levels of polyol-modified crystalline waxes could be obtained.

The paints were cured for 30 min at 130 ° C.

The paint was subjected to a scratch test. A hammer (500 g) was fitted with a ScotchBrite® 7448 type S ultrafine fleece and a defined number of double strokes were carried out. The gloss was determined using a gloss meter (Erichsen Picogloss 503) (60 ° measuring geometry) and the samples were then tempered at 130 ° C. for 30 minutes. The gloss was then measured again as described and the cycle was repeated several times

Double strokes Comparison 1 Example 1 Example 2

Gloss [%] gloss [%] gloss [%]

0 100 100 100

50 35 36 56

T = 130 ° C 67 81 95

100 19 33 68

T = 130 ° C 33 70 90

150 15 39 44

T = 130 ° C 13 65 54

200 10 28 44

T = 130 ° C 10 48 64

Claims

claims

Coating compositions containing as structural components

(A) at least one ester having at least two hydroxyl groups, formally composed of

(A1) at least one fatty acid having at least 12 carbon atoms and

(A2) at least one polyol having at least three hydroxyl groups,

(B) at least one optionally blocked di- or polyisocyanate, and

(C) at least one polyhydroxy compound.

Coating compositions according to Claim 1, characterized in that the compound (A1) is an alkane- or alkenecarboxylic acid.

Coating compositions according to Claim 1, characterized in that the compound (A1) is selected from the group consisting of lauric acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonanoic acid, arachidic acid, behenic acid, lignoceric acid, hexacosanoic acid, octacosanoic acid, triacontanoic acid , Dicricanoic acid, tritricosanoic acid, tetratricanoic acid, pentatricosanoic acid, oleic acid, linoleic acid and linolenic acid.

Coating compositions according to one of the preceding claims, characterized in that it contains three to six hydroxyl groups.

Coating compositions according to one of the preceding claims, characterized in that the compound (A2) is selected from the group consisting of trimethylolbutane, trimethylolpropane, trimethylolethane, pentaerythritol, glycerol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol, diglycerol, threitol, erythritol, adonite (Ribit ), Arabitol (lyxite), xylitol, dulcitol (galactitol), maltitol and isomalt.

Coating compositions according to one of the preceding claims, characterized in that the compound (A2) is alkoxylated one to three times per hydroxyl group.

Coating compositions according to one of the preceding claims, characterized in that the compound (A2) is ethoxylated one to three times per hydroxy group.

8. Coating composition according to one of the preceding claims, characterized in that the melting point of the compound (A) at least 45 ° C be wearing.

Coating composition according to one of the preceding claims, characterized in that compound (B) is selected from the group consisting of urethanes, biurets and isocyanurates of 1,6-hexamethylene diisocyanate (HDI) or 1-isocyanato-3-isocyanato-methyl-3,5 , 5-trimethyl-cyclohexane.

Coating composition according to one of the preceding claims, characterized in that compound (C) has a hydroxyl number of 16.5 to 264 mg KOH / g of solid resin.

Coating compositions according to one of the preceding claims, composed as follows:

(A) from 0.1 to 20% by weight,

(B) from 20 to 50% by weight,

(C) from 20 to 50% by weight,

typical paint additives (D) from 0 to 5% by weight,

Pigments and / or fillers (E) from 0 to 60% by weight, with the proviso that the sum always gives 100% by weight.

12. A process for the self-healing of cured coatings according to any one of the preceding claims, characterized in that the coating is heated for a period of at least 10 minutes to a temperature which is at least 25 ° C above the glass transition temperature of the coating.

13. Use of compounds (A) as defined in claim 1 as a reaction partner with di- and polyisocyanates in two-component polyurethane coatings.