DE2025173C3 - Use of a storage-stable coating composition for coating rubber-like elastic substrates - Google Patents

Description

This invention relates to the use of one in one Packaging packaged storage-stable coating compound for the production of stretchable coatings on rubber-like elastic substrates from a reaction product containing urethane groups, a Aminoplasts, an organic solvent and, if necessary, customary additives.

Recent developments in the technology of manufacturing coatings have resulted in coatings which are suitable for application on hard-to-coat substrates of various types and a number have different properties. Coatings of excellent appearance and excellent quality are obtained Durability that will stand up to harsh environmental conditions. To the coatings to which higher demands are made of vehicles, for example automobiles, which also under the action of the weather and under various other forms of wear over a need to keep their good looks for a long time.

Interest has recently turned to the use of rubber-like, elastic fabrics for Objects too. that are exposed to mechanical shock or shock loads, such as shock absorbers and molded parts of automobiles, protruding corners and surfaces of industrial machines, Floor strips and other parts of doors and house entrances, etc. The use of these substances exists increased protection against permanent damage in the material structure, but you have to put the objects To give the desired appearance, the surface of which is provided with a decorative protective coating, which in the Use can also be damaged. The coatings of the more common types, including those which have heretofore been used on rubber and similar stretchable articles, however does not have the required combination of properties. These properties are:

1. Extensibility: This property is necessary in order to take advantage of the elastic or resilient Layer support can reach its full effect without affecting the uniform surface of the Coating is damaged.

2. Tensile Strength: A high level of tensile strength is necessary to prevent the film from falling into the Use tears.

3. Package stability: For the purpose of easy handling in use, the liquid Coating mixture can be kept for a long time under given conditions without that in it resin may gel or depolymerize.

4. Resistance of the film: Certain coatings that are stretchable and have a relatively low tensile strength lose these properties with aging and especially when the coating demolishes Sunlight, the weather and similar influences is exposed.

5. Impact resistance: The coating must have an impact resistance at various temperatures that Temperatures correspond to those occurring in extreme weather conditions, i.e. H. Temperatures between -29 ° C and + 49 ° C.

6. Adhesion: The coating must have the ability to be sufficiently strong on the various substrates to adhere to which it is applied, e.g. B. stretchable materials such as foams, rubber and the like, and metals such as mild steel. In addition, the coatings must be used as intermediate layers sufficiently high adhesive strength to other coating layers and to different types of coating Have primers / primers.

7. Resistance to chemicals and moisture: These properties relate to resistance of the coatings against saponification under the action of acids and alkalis, their resistance against various solvents and their resistance to an atmosphere of high Degree of humidity and great warmth.

8. Resistance to cracking in the temperature-humidity cycle: This property is important when the coating is exposed to the rapid changes in temperature and humidity that automobiles can experience while driving or during storage. This property is tested by alternately to ^'5 the influence of exposing the coated with the coating subject to high temperatures and high humidity and low temperature and low humidity.

Other properties which are important for the usability of the coating mixers under the commercial aspect ^M relate to their sprayability at suitable solids contents, their non-toxicity and their low sensitivity to moisture.

It is very difficult to achieve the above properties in their entirety because one or several of the desired properties in most cases the use of substances and preparations make necessary, which usually cause a deterioration in the other properties desired.

Coating compositions are known and ^w based on polyurethane ^resins: n described numerous publications. DE-PS 10 90 449 shows coating compositions which contain the i <eaktio.isprodukt of 4,4'-methylene-bis (cyclohexyiisocyaate) and an alkyd resin as a film former. The alkyd resin should be dui. η condensation ^j5 tion of a polybasic acid or its anhydride with a polyhydric alcohol and a fatty acid are prepared. These reaction products can be used in admixture with urea-formaldehyde resins or melanin-formaldehyde resins.

GB-PS 11 28 943 relates to the production of a Polyurethane product that is used in combination with an aminoplast as a coating material can. For the production of the polyurethane product is a polyisocyanate with an alkyd resin from a Phthalic acid, a dimer of an unsaturated aliphatic monocarboxylic acid, and one or more Glycols unset.

In US-PS 32 42 230 are mixtures of water-soluble polyurethanes and phenolic and amino resins described. The water-soluble polyurethanes are water-soluble reaction products of Polyalkylene ether glycols and a diisocyanut.

In FR-PS 15 44 042 coating compositions are described that a polyurethane based on a Contain polyether polyol and an aminoplast.

GB-PS Il 44 250 shows coating compositions which are effective at room temperature and which contain a mixture of polyurethane polyol and an aminoplast. These coating compounds are used to coat ^Μ metals and glass.

It has now been found that by using a in a pack storage-stable coating composition packaged certain slightly cross-linked urethane Unisetzungsprodukten egg ^h 'ncs polyisocyanate and a polyester polyol, an aminoplast, an organic solvent and optionally conventional additives, coatings of high ductility and tensile strength rubber-like elastic substrates obtained.

The object of this invention is therefore the use a storage-stable coating compound packed in a pack

a) an urethane-containing urethane-group-containing substitution product of a polyisocyanate and a polyfunctional

b) an aminoplast,

c) an organic solvent and given ifalls

d) usual additives,

for covering rubber-like elastic substrates, wherein the reaction product is an ungelled, hydroxyl-containing urethane reaction product organic polyisocyanate and an organic material having multiple hydroxyl groups, wherein a larger proportion of this material is a polyester polyol made from

(a) an alkonoi component having an average functionality of at least about 1.9 and

(b) an acid component has been produced. the essentially from one or more carboxylic acids or their anhydrides with 2 to 14 Carbon atoms in the molecule and has an average functionality of at least 1.9.

wherein the alcohol component and the acid component a total of no more than about 1 Gram-moles of compounds with a functionality of 3 or more per 500 g of the alcohol component plus Contain acid component.

It is surprising that the coating compositions used in the invention are crosslinked, heat-cured Coatings result even though they are shelf-stable in a package. The one from the masses according to the invention The coatings produced exhibit the properties described in the introduction to a satisfactory degree Dimensions and in a combination. as could not be achieved with known coating compounds.

Examples of rubber-like elastic substrates or carriers are polyurethane, polyvinyl chloride and polyethylene foams, natural and synthetic rubber. Rubber foam and various elastomeric plastics.

The coating compositions contain an isoeyanate-modified component as an essential component. Hydroxyl group-containing resin which is obtained by mixing an organic material with several hydroxyl groups, a large proportion of which is an essentially linear polycster polyol . with a Polyisocyanai reacts. To produce the coating compounds, the isocyanate-modified resin is mixed with an aminoplast resin and the other components.

The alcohol component of the polyester polyol used must have an average functionality of at least eiwj 1.9 and consists of most Substantially fall from one or more diols. One can also use triols or higher polyols use as some branching is desired. however, the polyester should not be highly branched. One can also use a small amount of a monoalko Add hols especially if larger amounts of higher pole volutes are used.

If very high molecular weight polyols are used in certain cases, these can consist largely or entirely of compounds with a functionality of more than 2.

Diols of the kind that are commonly used for the production of polyesters are those

Alkylene glycols such as ethylene glycol. Propylene glycol, butylene glycol and neopentyl glycol, and other glycols, such as hydrogenated bisphenol A, cyclohexane dimethanol, caprolactone diol (the reaction product of caprolactone and ethylene glycol). hydroxyalkylated bisphenols, polyether glycols, for example poly (oxytetramethylene) glycol and the like. However, other diols of different types and, as stated, polyols can also be included higher functionality can also be used. ΑΈ Polyols of this type are for example Trimethylolpropane, trimethylolethane, peniaerithritol and the like and furthermore polyols of higher molecular weight, such as those obtained by the oxalhylation of low molecular weight polyols are called. An example of such a polyol with The higher molecular weight is the reaction product of 20 moles of ethylene oxide and 1 mole of trimethylolpropane.

The acid component of the polyester consists of essentially of carboxylic acids or anhydrides with 2 to 14 carbon atoms per molecule. The acids have an average functionality of at least about 1.3. The Säurckornpor.erite contains in most Cases at least about 75 mol% dicarb -.- n acids or their anhydrides. The functionality of the acid component is based on similar considerations that are in Relationship with the alcohol component were decisive, with the overall functionality of the System is to be taken into account.

Examples of acids that can be used are phthalic acid. Isophthalic acid, terephthalic acid, tetrahydrophthalic acid. Hexahydrophthalic acid, adipic acid, azelaic acid. Sebacic acid. Malic acid, glutaric acid, hexachloroheptenedicarboxylic acid, tetrachlorophthalic acid and other dicarboxylic acids of various types. The polyesters can contain minor amounts of a monobasic acid. such as benzoic acid. You can also use higher polycarboxylic acids, such as trimeluteic acid and tricarballyic acid use. If acids are mentioned above, the anhydrides of these can of course also be used Acids, insofar as they form anhydrides, can be used instead of the acids. The polyester contains preferably, at least as part of the acid component, an aliphatic dicarboxylic acid.

The polyester is produced by known processes, the reaction conditions and the ratio of the reactants being chosen so that a product with residual hydroxyl groups is formed. The number of hydroxyl groups contained in the product can vary, but the hydroxyl group should generally be at least about 30, preferably more than 80.

Mixtures of polyester polyols can also be used as organic material with several hydroxyl groups are used with polyether polyols. Such polyether polyols have a hydroxy equivalent of at least about 100 and contain a total of no more than about 1 gram mole with one Functionality of 3 or more per 500 g of the polyether polyol. You can also use smaller quantities other hydroxyl-containing compounds, such as niedermo- "<> lecular polyols. especially diols such as 1,4-butanediol or Neopentyl glycol monohydric alcohols and polyfunctional Compounds with one or more hydroxyl groups such as ethanolamine can be used. Suitable are also compounds, the other active, ^; Contain hydrogen-containing groups, such as water and polyfunctional amines. Examples are; IsoDhoronediamine. μ menthediamine, propylenediamine, hexamethylenediamine. Diethylenetriamine, triethylenetetrarnine, Diethanolamine and others

As an organic polyisocyanate. the one with the hydroxyl group-containing Material is implemented, you can basically use any polyisocyanate, for example Hydrocarbon polyisocyanates or substituted hydrocarbon diisocyanates. Lots of such organic Polyisocyanates are known in the literature and in practice; may be mentioned

p-phenylene diisocyanate, biphenyl diisocyanate,

Toluene diisocyanate,

S.S'-DimothyM ^ '- biphenylene diisocyanate,

1,4-tetramethylene diisocyanate,

Hexamethylene diisocyanate,

2.2,4-trimethyl-1,6-hexylene diisocyanate,

Methylene bis (phenyl isocyanate),

Lysine methyl ester diisocyanate,

Bis (isocyanate ethyl) fumarate, isophorone diisocyanate

and methyl cyclohexyl diisocyanate.
Addition products of diols with terminal isocyanate groups can also be used, such as ethylene glycol, 1,4-butylene glycol, polyalkylene glycols, etc. These compounds are iterated by adding more than one mole of a diisocyanate, for example one of the type mentioned, with one mole of a diol to form a longer chain Reacts diisocyanate. It is also possible to add the diol together with the diisocyanate.

While diisocyanates are also preferred, higher polyisocyanates can also be used as part of the organic polyisocyanates can be used, for example 1,2,4-benzene triisocyanate and polymethylene polyphenyhsocyanate.

Preference is given to using aliphatic diisocyanates since, as has been found, these are used in the finished product Coating can achieve better color retention. Examples of such diisocyanates are bis (isocyanatocyclohexyl) methane, 1,4-butylene diisocyanate and methylcyclohexyl diisocyanate. The ratio of the diisocyanate to the polyvalent compound containing hydroxyl groups, d. H. for the polyester polyol or polyether polyol is chosen so that a hydroxyl group-containing Product received. This can be achieved by the polyisocyanate in a lower than the stoichiometric amount used, i.e. less than one isocyanate group for one hydrocyl and carboxyl group in the polyvalent compound containing hydroxyl groups. A higher, i.e. H. a stoichiometric or an isocyanate level above this can then be used if the reaction takes place in the desired stage is completed, as is done by adding a compound to the remaining Isocyanate groups reacts. Examples of such compounds are water, alcohols and amines.

To the conversion between the hydroxyl-containing Material and the polyisocyanate in a desired stage of their course, which is determined by the viscosity is to finish, you can add a polyfunctional alcohol, which also results in remaining Introduces hydroxyl groups. Amino alcohols, such as ethanolamine, are particularly suitable for this purpose or diethanolamine, since the amino groups react preferentially with the isocyanate groups present. Also polyols, such as ethylene glycol, trimethylolpropane and polyester or polyethers with terminal ends Hydroxyl groups can be used for this.

Even if '..!' In common, the relationship between the Components of the polyester polyol, the polyisocyanate and any terminating agent used

can be varied, every person skilled in the art knows that the Quantities have to be churned in such a way that gelling prevents and a non-gelled hydroxyl group-containing Urethane reaction product is obtained. The hydroxyl number of the urethane conversion product should be at least 10, preferably 20 to about 200.

The urethane reaction product is mixed with an aminoplast (amine-aldehyde resin) to produce the coating material. Aminoplasts are aldehyde condensation products of melamine, urine and similar compounds. Products which are obtained by reacting formaldehyde with melamine, urea or benzguanamine are generally in use and preferred for the purposes of the present invention. However, one can also use the condensation products of other amines and amides, e.g. ! Example, aldehyde condensates of triazines, diazines, triazoles, guanidines, guanamines and a ky - "nrl;!. Examples irylsiibstiluierte derivatives of these compounds such as alkyl and aryl substituted urea w fabrics and alkyl and aryl substituted melamines of the latter compounds are N, N-dimethylurea, benzourea, dicyandiamide, formylguanarnine, acetoguanamine, ammeline.2-chloro-4,6-diamino-1,3,5-triazine,

6-methyl-2,4-diamino-1,3,4-triazine, 3,5-diaminotriazole, triaminopyrimidine. 2-mercapto-4,6-diaminopyrimidine, 2,4,6-triethyltriamino-l, 3,5-triazine and the like, albeit as an aldehyde in most cases Formaldehyde is used, similar condensation products can also be obtained from other aldehydes, for example acetaldehyde, crotonaldehyde, acrolein, benzaldehyde, furfural and others. getting produced.

Contain the amine-aldehyde condensation products Methylol or similar alkylol groups. In most cases, at least part of this will be Alkylol groups etherified by reaction with an alcohol, being in organic solvents soluble resins will be included. Any monohydric alcohol can be used for this purpose, for example methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol and others, as well as benzyl alcohol and other aromatic alcohols, cyclic alcohols such as cyclohexanol, monoethers of glycol such as diethylene glycol monoethyl ether, and halogen-substituted or other substituted alcohols such as 3-chloro-propanol. The preferred amine-aldehyde resins are etherified with methanol or butanol. In some cases the alkylol groups of the condensation product to form acyl groups, e.g. B. with acetic acid, implemented, or implemented with amines, for example morpholine.

In order to achieve optimal properties, the coating composition preferably contains a polyester poly! with a low glass transition temperature, in particular a glass transition temperature below about 25 ⁼ C. The addition of such a polyester polyol brings about a balance between flexibility and hardness. The polyether polyols optionally used in a mixture with a polyester polyol have a low glass transition temperature in many cases. Polyester polyols, which have a low glass transition temperature, consist in particular of acyclic reactants such as adipic acid, azelaic acid and alkylene glycols. Poly (neopentyl adipate) is a suitable example. Other polymeric polyols with good properties are the condensates of lactones with polyols, for example the condensation product of caprolactone and ethylene glycol. Propylene glycol or trimethylol propane. The amounts of the components used in the coating compositions depend largely on the nature of the individual components. for example of the aminoplast resin used in each case and of the type of polyester polyol used. In most cases, the coating composition contains resinous ingredients from about 50 to about 95 percent by weight urethane reaction product and from about 5 to about 50 percent by weight aminoplast resin.

The organic material having a plurality of hydroxyl groups can be polyether polyols in addition to the polyester polyol included in various ways. Either the polyether polyol can be used in the polyester as part of the Polyol components are present, or an adduct can be made from the polyether polyol and the polyisocyanate or prepare prepolymer with terminal isocyanate groups. A third possibility is that the polymeric polyol as such before or after the reaction of the polyester with the Polyisocyanate mixes with the polyester. The choice of procedure depends on the particular one used Components and the desired properties. In each of these cases, however, contains the received Product both “hard” and “soft” segments in the manner of block copolymers.

The coating compounds used in the invention, which are storage-stable in packaging and are therefore also referred to as pack-in coating compounds can be, according to conventional methods, for. B. by spreading, dipping, flowing inter alia, can be applied. In most cases, however, it is applied by spraying. One uses the methods and devices customary for this purpose.

The coatings are cured at elevated temperatures. The hardening splinted mostly in the range of about 20 to about 40 minutes at a temperature of 6O ⁰ C to 127 ° C, but may also have higher or lower temperatures and shorter in a corresponding manner and longer times are used. In detail, the curing conditions used also depend on the type of carrier and on the components used in each case for the preparation. If necessary, acidic catalysts and other curing catalysts can be added as curing auxiliaries. Such additives allow the use of lower temperatures and / or shorter curing times.

The invention is illustrated by the following examples described in more detail. These examples are intended to illustrate the invention, but not to those disclosed therein Limit details. All parts and cited in the examples and throughout the description Unless stated otherwise, percentages are parts by weight and percentages by weight.

example 1

Filling 126.9 parts of neopentyl glycol, 22.1 parts of trimethylolpropane, 72.3 parts of adipic acid and 123.2 parts of isophthalic acid into a reaction vessel and the mixture is heated for 30 minutes at 200 ⁰ C and then to 220 ° C until the resin the Gardner-Holdt viscosity F (60% solids in methyl ethyl ketone), an acid number of about 10 and a hydroxyl number of about 100. 70 parts of the polyester polyol obtained are mixed with 35 parts of methyl ethyl ketone and

7.1 parts of i Methsn-bis-feyclohexylisocyanat) heated da * mixture for 20 hours at 65.B C. then for 3 hours it is cooled to 48.9 C. and then sets 22 parts of n-butanol and 0.3 g Äthanoiamin to. The product has the (iiirdner-Holdt viscosity /.I - Z2. A content of about b0% of non-volatile solids and the acid number 3.7.

A gray coating is produced. by the urethane reaction product obtained in a Amount of 196.5 parts with 18.7 parts of hexakis (methoxymethyljmelamine, 15.8! 'Hurry poly (oxetetramethylene glycol, 7.5 parts of a 2O ° / otgen solution of cellilose acetobutyrate in a mixture of 80 parts Toluene and 20 parts of ethanol, 67.5 parts of a pigment paste, 217.5 parts of toluene. 49.5 parts of ethylene glycol monoethyl ether acetate. 99 parts of ethylene glycol monoethyl ether, 74.5 parts of diacetone alcohol and 1.5 Mix parts of p-toluenesulfonic acid.

The pigment paste used in this mixture was dissolved in a solution of one of 146 parts of neopentyl glycol. 112 parts of adipic acid, 191 parts of isophthalic acid and 103 parts of trimethylolpropane were ground. The paste was made by blending 89 parts of polyester (60% solids in xylene). 260 parts T1O2. 13 parts of a black pigment, 28 parts of xylene, 43.5 parts of methyl isobutyl ketone and 10.4 parts of butanol. Mill the mixture in a ball mill until a particle size of 6 ¹ /: Hegman is reached, and add 50 parts of toluene to the mixture.

D '<: The coating composition obtained has good storability and excellent properties. When they are cured at 12T ³ C, for example, 60 minutes, one (181% maximum elongation), and excellent tensile strength is obtained a film of superior extensibility (2.09 x 10 ⁵ g / cm measured in the Instron test apparatus). As a cover on polyurethane foam of the type

Example 3

A coating composition according to Example 1 is produced.

but uses a commercially available resinous, less highly methylated one instead of the aminoplast resin Melamine formaldehyde resin. The product has similar properties to that of Example 1.

Example 4

It is made according to Example 1 from the one described there Urethane reaction product and the pigment paste also described there using a butylated mclamine formaldehyde resin obtained from 5.5 moles of formaldehyde and 6 moles of butanol per mole of melamine of a coating compound. The resin is applied in the form of a 60% solids solution, whereby Butanol and xylene in a ratio of 25:75 can be used as solvents. The coating compound contains 110 Parts urethane reaction product, 42 parts butylated melamine resin, 10.5 parts poly (oxytetramethyien) giykoi (Mol.wt. 1000), 45 parts of pigment paste, 5 parts of cellulose acetobutyrate solution according to Example 1.130 parts Xylene, 40 parts of ethylene glycol monoethyl ether acetate. 80 parts of ethylene glycol monoethyl ether, 50 parts of diacetone alcohol and 2 parts of p-toluenesulfonic acid.

With this preparation, stretchable films are obtained which have a somewhat lower maximum elongation than the above-mentioned films, but a good tensile strength (2.65 · 10 ⁵ g / cm ² ). When applied to foam like

Described in Example 1, the coating has good impact resistance and other properties.

Example 5

A polyester containing poly (oxytetramethylene) glycol in the polyester molecule is made from 4875 parts Neopentyl glycol, 3014 parts adipic acid. 5132 parts of isophthalic acid, 921 parts of trimethylolpropane and 3750 parts

as cf lüT οίυίη ^ αιιιμίςι du Aüiuiiiubiicn Vci w'ciiuct WiTu (density 0.64 g / ccm with a Shore "A" hardness of 78) it shows satisfactory properties, especially an impact strength of more than 184 cm / kg ( measured in a Gardner Variable Impact Tester). The preparation is suitable as a primer for foams of the type mentioned and similar substances.

Example 2

It is made from the urethane reaction product according to Example 1 and one also according to Example 1, but pigment paste prepared without black pigment produces a white coating mass. The pigment contains 61.5% T1O2, 12% polyester and suitable solvents. the The coating compound has the following components:

74 parts of urethane reaction product, 10 parts of hexakis (methoxymethyl) melamine, 40 parts of pigment paste, 6 parts polyfoxytetramethylene glycol!) (Mol.wt. 1000). 5 parts of a cellulose acetobutyrate solution Example! 1, 0.5 parts of p-toluenesulfonic acid, 100 parts of methyl ethyl ketone and 50 parts of ethylene glycol monodethyl ether acetate.

Films produced from this mass have, after a curing treatment of 60 minutes at 121 ° C., a maximum elongation of 177% and a tensile strength of 135 ⁵ g / cm ² . If the composition is applied as a coating to a primed foam of the type described in Example 1, a coated product is obtained which has excellent properties, above all good impact strength.

Share Po'.yioxytctrarncthyien) glyko! (MoL weight! 000). The polyester obtained has an acid number of 5.9 and a hydroxyl number of 59. 1800 parts of this polyester are reacted in 1080 parts of methyl isobutyl ketone with 168 parts of methane bis (cyclohexyl isocyanate). The mixture is heated 6 ^! / 2 hours at 65.6 ° C and 2605 parts of the product obtained, 3.9 parts of ethanolamine and 520 parts of butanol. The product has a Gardner-Holdt viscosity of Z 3. It contains 51.2% non-volatile solids.

A coating composition is prepared from the urethane reaction product obtained by adding it in an amount of 76 parts to 7.5 parts of hexakis (methoxymethyl) melamine, 37 parts of the pigment paste according to Example 2, 5 parts of Celiulose acetate butyrate solution according to Example 1, 60 Share ÄthylengTykolmonoäthylätheracetai. 30 parts of methyl ethyl ketone, 80 parts of toluene and 0.75 parts of p-toluenesulfonic acid are mixed. Films made from this material have, when they are cured for 30 minutes at 121 ^° C., excellent extensibility (187% maximum elongation) and excellent tensile strength (1.86 · 10 ⁵ g / cm ² ). If you, as in example 2,

Used as a protective coating, they result in coatings with good overall properties.

Example 6

A mixture of 1000 parts of poly (oxytetramethylene) glycol (mol. Wt. 1000), 574 parts of polyester polyol (obtained from neopentyl glycol and adipic acid; Acid number 0.3, hydroxyl number 35), 82.3 parts of 1,4-butanediol, 128.7 parts of 1,6-hexanediol

and 892.5 parts of dimethylformamide and are 1220 parts of this mixture with 472 parts of methane bis (cyclohexyl isocyanate, 325 parts of cyclohexanone, 860 parts of dimethylformamide, 8.1 parts of diethylenetriamine and 14.4 parts Divide a 1% solution of dibutyltin acetate in cyclohexanone together. It is called that mixture obtained for W2 hours! 2I "C and there then 272 parts to 2717 parts of the resin obtained Butanol and 10.7 parts of diethanolamine are added. The product contains 40.5% non-volatile solids. It has the acid number 0.63.

A coating composition is prepared from the urethane reaction product by mixing it in an amount of 632 parts with 227 parts of pigment paste, 134 parts of methylated melamine-formaldehyde resin, 8 parts of silica pigment, 1110 parts of methyl ethyl ketone, 123 parts of toluene and 4 parts of p-toluenesulfonic acid. The pigment paste used was ground in a solution of 146 parts of neopentyl glycol, 112 parts of adipic acid, 191 parts of isophthalic acid and 103 parts of trimethyloipropane. The paste is made by mixing 89 parts of polyester (60% solids in xylene). 260 parts of TiO ₂ , 28 parts of xylene, 43.5 parts of methyl isobutyl ketone and 10.5 parts of butanol. This mixture is ground in a ball mill until a particle size of ½ Hegman is reached, whereupon 50 parts of toluene are added.

The coating composition obtained has a good shelf life

ability and excellent properties. If it is applied to polyvinyl chloride) foam and cured for 30 minutes at 121 ° C., a coating is obtained that has good impact strength at low temperatures and good tensile strength (2.5 · 10 6 g / cm ² , measured with the Instron tester).

Example 7

The procedure is as in Example 6, but hexakis (methoxymethyl) melamine is used as the aminoplast resin. The properties are essentially the same as in Example 6.

Example 8

The procedure is as in Example 6, but one with 5.5 moles of formaldehyde and 6 moles of butanol to 1 mole is used Melamine produced butylated melamine formaldehyde resin as an aminoplast resin. You get a good result se.

Example 9

The procedure is as in Example 6, but a poly (oxytctramethylcn) glycol (mol. Wt. 1000), 34 parts of 1,4-butanediol, 45 parts 1.6-hexanediol, 202 parts of polyester polyol according to the example I and 367 parts of methane bis (cyclohexyl isocyanate) produced urethane reaction product. The results are essentially the same as the results obtained in Example 6.

Claims (7)

Patent claims: 1. Use of a storage-stable top layer packed in a pack a) a reaction product containing urethane groups a polyisocyanate and a polyfunctional compound, b) an aminoplast, c) an organic solvent and optionally Ό d) usual additives, for coating rubber-like elastic substrates, the reaction product being a
contains ungelled, hydroxyl-containing urethane reaction product of an organic polyisocyanate and an organic material having a plurality of hydroxyl groups, a major proportion of this material being a polyester polyol which is composed of (a) an alcohol component having an average functionality of at least about 1.9 ^M and (b) an acid component has been prepared consisting essentially of one or more Carboxylic acids or their anhydrides with 2 to 14 carbon atoms in the molecule and has an average functionality of at least 15, wherein the alcohol component and the acid component a total of no more than about 1 gram-mole of compounds with a functionality of 3 or more per 500 g of the alcohol component plus acid component included. 2. Use according to claim 1, characterized in that the material with several Hydroxyl groups of the urethane reaction product in addition to the polyester polyol Polyether poly! having a hydroxyl equivalent of at least about 100 and a total of no more than about one gram-mole of compounds having a functionality of 3 or more Contains 500 g of the polyether polyol. 3. Use according to claim 1 or 2, characterized in that the material with several hydroxyl groups, the urethane reaction product in addition to the polyester polyol * ⁵ also contains a low molecular weight diol. 4. Use according to any one of claims 1 to 3. characterized in that the urethane reaction product has a hydroxyl number of at least 10. 5. Use according to any one of claims 1 to 4, characterized in that the urethane reaction product contains a polyester polyol with a glass penetration temperature below about 25 ° C. 6. Use of the coating composition according to one of claims 1 to 5 for coating polyurethane foam. 7. Use of the coating composition according to any one of claims I to 5 for coating polyvinyl chloride foam. 60