CH627096A5 - Process for the production of coatings - Google Patents

Description

The invention relates to a method for producing coatings or cover layers on substrates by curing a coating composition which contains a polymerizable amino plastic resin as a binder, with the aid of UV light or with the aid of electron beams.

It is known that coatings and top layers can be produced on substrates by UV irradiation of coating compositions which contain polymerizable binders. So far, unsaturated polyesters have mainly been used as binders, but these form rather brittle and discolored coatings. In addition, acrylate-modified epoxy resins and polyurethanes were used, but these are relatively expensive or have to be synthesized using complex processes.

Polymerizable aminoplast resins are known from US Pat. No. 3,020,255, which are prepared by reacting aminoplasts with hydroxyacrylates. They can be cured together with other polymerizable compounds at elevated temperature by adding polymerization catalysts. SZ-PS 560 729 describes a process for curing aminoplast resins by ionizing radiation. The aminoplast resins are made by reacting melamine / formaldehyde condensates with (meth -) - acrylic acid in the presence of weak acids, e.g. Formic acid.

The invention was based on the object of developing a method for producing coatings by irradiation with UV light, using cheap and easy-to-produce binders.

The present invention was also based on the object of further developing this method and making it accessible to an application which is advantageous in terms of processing technology, namely the production of laminated fabrics, and to achieve curing times which are as short as possible for this application.

The invention relates to a method for producing coatings on substrates by curing a coating composition which contains polymerizable binders and optionally photoinitiators, with the aid of light of a wavelength of about 200 to 500 nm or electron beams of an energy between 50 and 500 KeV by using a Coating composition containing:

A. 99.9 to 20% by weight of a reaction product of a) optionally completely or partially etherified amine / formaldehyde condensates and b) (meth) acrylic compounds containing hydroxyl or amino groups,

wherein one third to 1 mol of the acrylic compound is used for 1 equivalent of CH2-0 groups of the amine / form aldehyde condensate,

B. 0 to 60% by weight of organic compounds which can be polymerized at room temperature and are liquid,

C. 0 to 80% by weight of pigments or fillers,

D. 0 to 20% by weight of further organic paint auxiliaries,

E. 0 to 50 wt .-% of other polymerizable unsaturated binders and optionally

F. 0.1 to 20% by weight of a photoinitiator system,

where the percentages add up to 100.

According to an advantageous embodiment of this method, the coating composition is applied to one side of a flat intermediate carrier which can be glued to the substrate to be coated using heat and / or pressure, cured and the other side of the intermediate carrier coated to one side is glued to the substrate.

It is particularly advantageous if the polymerizable aminoplast resin A used is one which, by reacting the amine / formaldehyde condensate a with the hydroxyl- or amino-acrylate b in the presence of organic or inorganic acids with a pK value of <3 , 0 was produced. Polymerizable aminoplast resins of this type show a particularly high reactivity, i.e. particularly short exposure times are possible with UV curing.

Component A is a reaction product of an amine / formaldehyde condensate a and a (meth) acrylic compound b carrying hydroxyl or amino groups.

The amine / formaldehyde condensates a) are advantageously condensation products of amino, imino or amido group-bearing aminoplast formers with 1 to 2 mol of formaldehyde per amino, imino or amido group. The aminoplast formers that can be used include: melamine, urea, benzoguanamine, acetoguanamine, acetylene diurea, ethylene urea, propylene urea, and also carbamates and urones. These compounds are expediently condensed in the weakly alkaline range with formaldehyde, depending on the reaction conditions, simple reaction products or more highly condensed polymeric compounds can be formed. They are characterized by the

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I.

-N-CH2-0 group, where 1 or 2 -CH2-0 groups can sit on a nitrogen.

These condensation products can now be used directly for the coating composition. However, it is preferred to use them in whole or in part etherified form. This etherification is generally carried out in an acidic medium, using monoalcohols having 1 to 6 carbon atoms. Preferred are condensation products of melamine with 3 to 6 molecules of formaldehyde, some of which are etherified with monoalcohols, preferably with methanol or butanol. Component a can be used in bulk or in aqueous or alcoholic solution.

The amine / formaldehyde condensates a) are reacted with (meth) acrylic compounds b) carrying hydroxyl or amino groups. Monoesters of (meth) acrylic acid with alkane diols having 2 to 4 carbon atoms, such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxypropyl (meth) acrylate and butanediol monoacrylate, are preferred. Furthermore, N-methylol (meth-) acrylic amide and N-methylol (meth-) acrylic amide etherified with butanediol are also suitable. Acrylamide and methacrylamide are suitable as compounds bearing amino groups. Particularly good results are obtained when mixtures of (meth) acrylic compounds containing hydroxyl and amino groups are used in a molar ratio of 4: 1 to 1: 4.

The quantitative ratios in the above reaction are chosen so that 1 equivalent of -CH2-0 group of the amine / formaldehyde condensate V3 is used up to 1 mole of acrylic compound.

This reaction is preferably carried out in the presence of a strong organic or inorganic acid. The pK value of the acid in aqueous solution should accordingly be below 3.0, preferably below 2.0 (pK value tabulated e.g. in Handbook of Chemistry and Physics, 48th edition, 1967/68, D90 / D91). The pK value is to be understood as the negative logarithm of the dissociation constant, whereby in the case of polybasic acids, the dissociation constant of the first stage is meant. For example, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, oxalic acid, maleic acid and phthalic acid are suitable. Hydrochloric acid is preferred. The acids are advantageously used in amounts of 2 m Val to 60 m Val, preferably 3 m Val to 40 m Val per equivalent -CH2-0 group of the amine / formaldehyde condensate. In principle, however, it is also possible to work in a weakly acidic range, in some cases also in a neutral or slightly alkaline range.

The reaction is expediently carried out in the presence of 0.01 to 0.5% by weight of inhibitors, based on components a + b, which are intended to prevent the polymerization of the acrylic compounds. Suitable are e.g. Hydroquinone, hydroquinone monoalkyl ether, phenothiazine or salts of N-nitrosocyclohexylamine.

The reaction temperature can be between 50 and 120 ° C, preferably between 70 and 100 ° C. Water and / or volatile monoalcohols formed during the condensation are distilled off in the course of the reaction. This can either be done by using vacuum, e.g. between 50 and 200 Torr, or that the reaction is carried out in the presence of azeotropic entraining agents, e.g. Cyclo-hexane. The reaction generally lasts 10 minutes to 5 hours. It is terminated by neutralizing the catalyst acid with bases such as sodium hydroxide solution, soda or amines.

The polymerizable unsaturated aminoplast resins obtained generally have a viscosity between 400 and 10,000 mPas (20 ° C.). Low-viscosity resins are already usable coating compositions. Higher viscosity

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Resins are diluted with copolymerizable organic compounds B, which are expediently liquid at room temperature. These reactive diluents can be used in amounts of from 0 to 60, preferably from 10 to 50,% by weight, based on the coating composition. For example, butanediol diacrylate, trimethylolpropane triacrylate, N-vinylpyrrolidone, divinyl urea or 2-ethylhexyl acrylate are suitable.

In order to achieve special effects, inorganic or organic pigments C, such as e.g. Titanium dioxide or fillers, such as talc, in amounts of 0 to 80, preferably 3 to 60% by weight, based on the coating composition, are added.

Furthermore, the organic additives D customary in the paint industry, such as thixotropic agents, leveling agents, deaerating agents or lubricants, can be present in amounts of up to 20% by weight.

In addition to the polymerizable unsaturated aminoplast resins A, the coating compositions may also contain 0 to 50% by weight of other polymerizable unsaturated binders E, e.g. unsaturated polyesters or acrylate-modified epoxy resins, polyurethanes and saturated polyesters.

If they are to be cured with UV light, the coating compositions contain 0.1 to 20% by weight, preferably 1 to 15% by weight, of a photoinitiator system. Photoinitiators are compounds which, alone or together with sensitizers, decompose on exposure to radicals which can initiate the polymerization. Suitable systems are, for example, benzoins, benzoin ethers, benziles, benzil ketals, disulfides, di-thiocarbamates; also benzophenone, acetophenone, anthraquinone, xanthone and thioxanthone and their derivatives in combination with organic amines.

The coating compositions are suitable for the production of coatings and cover layers on any substrates, such as wood, metal, paper or plastic, as well as fillers or printing inks.

When curing is done by irradiation with UV light, UV light of a wavelength of about 200 to 500 nm is generally used. Details on UV curing can be found in the article "Photopolymerization" by H. Barzynski, K. Penzien and O. Volkert in Chemikerzeitung 96 (1972), pp. 545-551.

As a radiation source e.g. Mercury vapor lamps are suitable which emit UV light with a wavelength of about 200 to 500, preferably between 250 and 450 nm.

The curing can take place both in air and under inert gas, e.g. Nitrogen or carbon dioxide.

The irradiation time can be between 0.01 s and several minutes, preferably between 0.05 s and 10 s.

One embodiment of this method is

that the coating composition is applied to one side of a flat intermediate carrier and the other side of the flat intermediate carrier is glued to the substrate during or preferably after the coating composition has hardened.

The flat intermediate carrier must be able to be bonded to the substrate to be coated using conventional methods using heat and / or pressure.

Suitable flat intermediate carriers are, for example

1. Plastic films, e.g. those made from optionally plasticized polyvinyl chloride or vinyl chloride copolymers, from polyolefins, such as e.g. Polyethylene, polypropylene, polyisobutylene, optionally vulcanized, natural or synthetic rubber, made of polyester, e.g. Polyethylene terephthalate, polybutylene terephthalate, made of polyamide, e.g. Polyamide-6.6.

2. Impregnation foils, e.g. those made from noble cellulose or sodium kraft paper impregnated with conventional aminoplast resins, e.g. Primer and decorative films.

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3. Metal foils, e.g. those made of aluminum.

4. Films made from modified natural products, e.g. made of wood (e.g. veneers), cellulose, cellulose derivatives, e.g. Wood foil or Cellophan®, cork or leather.

5. Fabrics and nonwovens made of inorganic and / or organic fibers, such as e.g. those made of glass fibers, asbestos, cellulose, cellulose derivatives, such as e.g. Cellulose acetate; Synthetic fibers, such as polyamide, polyester, polyolefin, polyacrylonitrile fibers, and mixtures of such fibers.

6. Papers based on cellulose, cellulose / wood pulp, synthetic fibers such as polyester, polyamide, polyolefin, polyacrylonitrile or mixtures thereof, the usual fillers such as calcium carbonate, china clay and colorants and the like. a. may contain or be provided with coatings, e.g. Wallpaper.

These flat intermediate supports can be transparent, opaque or colored. These flat intermediate supports must be able to be bonded to the substrate to be coated using customary methods using heat and / or pressure. The gluing can be done either by softening or melting the flat intermediate carrier itself when heated, possibly under pressure, and thereby gluing to the substrate, or by the flat intermediate carrier using conventional adhesives in the form of melts, solutions, dispersions or powders is impregnated or coated and then bonded to the substrate under heat and optionally pressure. Suitable adhesives for this purpose are commercially available dispersion glues, thermosetting glues such as aminoplast precondensates or solvent-based systems based on polychloroprene. Solvent-free hot melt adhesives, heat seal adhesives or two-component adhesives are also used.

The intermediate carrier is generally bonded at temperatures up to approximately 250 ° C., optionally under a pressure of 0.05 to 2.0 N / mm 2, usually in roller, continuous or multi-stage presses.

Before the flat intermediate carrier is glued, it is coated on one side with the aid of light of a wavelength of approximately 200 to 500 nm or electron beam curable coating mass. The coating composition is cured by irradiation with UV light with a wavelength of approximately 200 to 500 nm or with the aid of electron beams with an energy between 50 and 500 KeV.

If the coating compositions are hardened with the aid of electron beams, it is generally not necessary to use a photoinitiator system (F).

Details on electron beam hardening can be found e.g. in Davison, W.H.T. Process Characteristics of Electron Beam Curing, JOCCA 52, 946 (1969).

As a radiation source e.g. Van de Graaf generators and other commercially available electron beam generators, which preferably emit electrons of this energy from 150 to 350 KeV. Common assemblies for generating electron beams are e.g. in A. Charlesby, Atomic Radiation and Polymers, 1960, Pergamont Press, Oxford. The coating composition to be hardened by means of electron beams is applied using customary application methods, e.g. by casting, rolling or knife coating, generally applied to the flat intermediate carrier in a layer thickness of 10 to 50 μm. Curing by means of electron radiation is generally carried out with the exclusion of air or under inert gas, e.g. Nitrogen or carbon dioxide.

0.5 to 5, preferably 1 to 2, Mrad are suitable as the radiation dose.

A device is expediently used to carry out the method according to the invention, in which the flat intermediate carrier coated with the coating to be hardened is carried out on a conveyor belt under the radiation source.

Another variant of the method is that the intermediate carrier is impregnated with an adhesive which contains the radiation-curable coating composition, so that the coating composition can be cured and the intermediate carrier can be glued to the substrate under radiation and simultaneous exposure to heat.

The radiation-curable coating composition is cured on the gluable flat intermediate carrier before or during the gluing to the substrate to be coated.

The particular and unforeseeable advantage of the method according to the invention is that it is possible in this way to provide substrates with particularly high-quality coatings without the coating of the top layer being adversely changed, in contrast to the more thermoplastic conventional coatings, e.g. those based on acid-curing amino resins. It is also advantageous that these high-quality coatings are obtained in significantly shorter times (curing times of the coatings according to the invention <1% of the curing time of the coatings obtained with conventional amino resins) and that the coating is applied to a still wet intermediate carrier, e.g. paper pre-impregnated with conventional amino resin, even on thin paper (é 30 g / m2), leads to perfectly closed and hardened surfaces.

The lacquered, adhesive intermediate carriers obtained by the process according to the invention can also be stored rolled up as plates or in the form of webs and, if necessary, glued to the substrate to be coated (“lacquer from the roll”),

Suitable substrates are preferably wood or wood-based materials, glass, metal, paper, plastic, but also all other rigid and elastic carrier materials.

The method according to the invention is particularly suitable for the production of wood-based materials finished with highly elastic finished effect films, such as chipboard, hard fiber or blockboard.

The parts and percentages given in the examples relate to the weight.

example 1

a) Binder production

390.0 parts of hexamethoxymethylmelamine

432.0 parts butanediol monoacrylate 0.5 parts hydroquinone 4.7 parts conc. hydrochloric acid

240.0 parts cyclohexane

The reaction mixture is heated to boiling. A mixture of water and methanol is removed via an azeotropic separator. The temperature rises from 70 to 85 ° C. After neutralization with aqueous sodium hydroxide solution, the cyclohexane is removed by distillation or vacuum distillation at 90 ° C. About 700 g of resin with a viscosity of about 1,500 mPas remain in the flask.

b) UV curing:

The resin was mixed with 4% benzoin butyl ether and at a belt speed of 20 n / min in a layer thickness of 15 h under nitrogen with a high pressure mercury tube with 80 watt / cm and a length of 20 cm (HOK 2-UV- Tube) irradiated. The resulting film is nail hard and shiny.

Example 2

a) 350.0 parts of a 70% aqueous solution of a tetramethylolmelamine partially etherified with methanol

390.0 parts hydroxypropyl acrylate 0.5 parts hydroquinone 2.4 parts conc. hydrochloric acid

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About 125 g are distilled off in vacuo at 70 to 80 ° C. in the course of 3.5 hours. It is neutralized with sodium hydroxide solution.

b) The resin mixed with 4% benzoin butyl ether at a belt speed of 10 m / min and irradiation with a UV lamp HOK 5 (tube length 50 cm) gives a nail-hard, shiny film.

Example 3

a) 1140.0 parts of an 80% methanolic solution of hexamethylol-melamine partially etherified with methanol 426.0 parts of acrylamide 1170.0 parts of hydroxypropyl acrylate 1.5 parts of hydroquinone 7.2 parts of conc. Hydrochloric acid A total of approx. 410 g is distilled off in vacuo at 70 to 120 ° C. over the course of 4.5 hours. The remaining resin is filtered after neutralization.

b) If the resin is mixed with 4% benzoin butyl ether and a 30 .mu.m thick film is irradiated at a belt speed of 7 m / min with air access using a HOK 5 UV lamp, a hard, glossy lacquer film is obtained.

Example 4 a) 187 parts of benzoguanamine

Adjust 389 parts of 40% formaldehyde with saturated sodium carbonate solution to pH 8. The reaction mixture is stirred at 85-90 ° for 45 minutes. Thereafter, 0.3 parts of hydroquinone

464 parts of hydroxyethyl acrylate (containing about 10% free acrylic acid) were added. It is distilled in vacuo at 80 ° C for 0.5 hours. After adding 3.4 parts of hydrochloric acid conc. vacuum distillation is continued at 80 ° C. for 2.5 hours (weight loss approx. 325 parts). Then 6 parts of 50% sodium hydroxide solution are added.

Discharge: 725 parts of resin with a viscosity of approx. 2200 mPas (at 20 ° C).

b) 145 parts of hydroxypropyl acrylate were added to the resin obtained in a). After adding 3% benzil dimethyl ketal, 100 / .i thick layers were irradiated with a HOK 5 UV tube. At a belt speed of 12.4 m / min. a scratch-resistant paint film was obtained.

Example 5

a) The procedure was as in Example 4, but no hydrochloric acid was added. The presence of small amounts of acrylic acid made the reaction medium slightly acidic. In the vacuum distillation at 80 ° C., 250 parts were distilled off over the course of about 1 hour.

Discharge: 790 parts of resin with a viscosity of approx. 1000 mPas (at 20 ° C)

b) The procedure was as in Example 4. For a scratch-resistant

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To get the best film, the exposure time had to be doubled.

Example 6

A walnut decor paper (30 g / m2) is mixed with a mixture of approximately equal parts of a commercially available aminoplast resin based on urea / formaldehyde (e.g. Kau-rit® impregnating resin 210 liquid or 420 liquid) and a dispersion of a thermoplastic acrylic ester copolymer with the addition of 0.7 % (based on aminoplast resin)

10% formic acid as a catalyst with a resin application of 40%, based on paper weight, impregnated. The impregnate is then dried at 160 ° C to a residual moisture content of approx. 8%.

On one side of the elastic base film thus obtained, the coating composition described in Example 2b), which contains benzil dimethyl ketal as the light initiator instead of benzoin butyl ether, and additionally with 15% of a silicate-based matting agent, e.g. Silcron G 300 from SCM Corp., Baltimore, was applied in a layer thickness of 20 g / m 2 and at a belt speed of 6 m / min with a high pressure mercury tube of 80 watt / cm and a length of 60 cm at a distance of Irradiated 25 cm. The finished effect film coated in this way is glued to a chipboard at 70 or 130 ° C under a pressure of 0.4-0.6 N / mm2.

Example 7

With the impregnation solution described in Example 6, a rosewood decor paper (90 g / m2) with a resin application of 80%, e.g. Paper weight, soaked and dried at 160 ° C to a residual moisture of approx. 8%. The paint spread and the sticking of the finished effect film are carried out under the same conditions as in Example 6.

Comparative experiments on examples 6 and 7

The elastic base films described in Examples 6 and 7 are produced.

As a paint spread, however, a conventional acid-curing paint consisting of 80 parts of hexamethoxymethyl melamine, 20 parts of a branched polyether containing hydroxyl groups and an OH number of approx. 380 (viscosity at 25 ° C = 650 ± 100 mPas), 10 parts of a silicate Matting agent (eg matting agent OK 412 from Degussa) and 20 parts of semi-concentrated hydrochloric acid. The application amount is 20 g / m2 (dry). The curing takes place for 1 min. at 100 ° C.

The finished effect films obtained in this way are again stuck at 70 and 130 ° C. under a pressure of 0.4-0.6 N / mm 2.

Evaluation of the plates produced according to Examples 6 and 7 and the comparative tests

The surface was tested in accordance with technical delivery conditions TL 7100-001, issue 3 of the Federal Office of Defense Technology and Procurement. The results are summarized in Table 1.

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Assessment = 0 = best grade

5 = worst grade

Table 1

exam

Plates according to example

70 ° C 130 ° C

according to example 70 ° C 130 ° C

Comparative experiment example 6 70 ° C. 130 ° C.

Comparative experiment example 7 70 ° C. 130 ° C.

Unity

0

0

0

0

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visual assessment of the

surface

1

0

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0

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5

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5

Water resistance

0

0

0

0

1

1

1

1

Resistance to alcohol

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0

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G

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0

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0

Resistance to soda

0

1

0

1

0

0

0

0

Cooking test

0/0

0/0

0/0

0/0

1/2

0/0

1/2

0/0

Heat resistance

0

0

0

0

0

0

0

0

Resistance to embers

1

1

1

1

1

1

1

1

In addition to the procedural and economic advantages of the coating composition according to the invention already described above, it can be seen from Table 1 that even when the coating is laminated on at low temperature, at least the surface resistances equal to those of the conventional paints are obtained. The uniformity of the surface and the complete closedness of the coating are particularly advantageous.

Example 8

A walnut decor paper (30 g / m2) is pre-impregnated with a customarily curable melamine-formaldehyde condensate (e.g. ®Kauramin impregnating resin 782 liquid + 0.4% of an ammonium salt, e.g. hardener 527 liquid) with approx. 80% resin application . The coating is then carried out on the still wet film with a UV-curing coating composition prepared in accordance with Example 1 and containing a urea / formaldehyde resin instead of the melamine / formaldehyde resin under the same conditions as in Example 6.

This film is laminated onto a chipboard at 140 ° C within 1 min under a pressure of 1.2 N / mm2.

The quality inspection carried out in accordance with Table 1 gives the following values:

Unity 0

visual assessment of the surface 0

Water resistance 1

Alkali resistance 1

Resistance to soda 0

Cooking sample 0/0

Heat resistance 0

Ember resistance 0

This procedure cannot be carried out with a conventional paint. Another advantage of this film is that it is particularly easy to structure due to its high elasticity.

Example 9

A rosewood decor paper (90 g / m2) is pre-impregnated as in Example 8 with a commercial melamine resin with 80% resin application and pre-dried at 160 ° C (residual moisture: 6%).

The subsequent painting is carried out as described in Example 6, the lamination as described in Example 8.

The surface quality test gives the following values:

Unity 0

visual assessment of the surface 0

Water resistance 0

Alkali resistance 1

Resistance to soda 0

Cooking sample 0/0

Heat resistance 0

Ember resistance 0

The surface obtained is characterized by very good consistency, uniformity and high resistance.

Even lamination of this film after air-conditioning (15 h / 70 ° C) does not change the film elasticity or the surface properties.

Example 10

A walnut decor paper (30 g / m2) is mixed with a mixture of approximately equal parts of a commercially available aminoplast resin based on urea / formaldehyde (e.g. Kaurit * resin 210 liquid or 420 liquid) and a dispersion of a thermoplastic acrylic ester copolymer with the addition of 0.7% ( based on aminoplast resin)

10% formic acid as a catalyst with a resin application of 40%, based on paper weight, impregnated. The impregnate is then dried at 160 ° C to a residual moisture content of approx. 8%.

On one side of the elastic base film obtained in this way, the coating composition described in Example 2a) is additionally coated with 15% of a silicate-based matting agent, e.g. Silcron G 300 from SCM Corp., Baltimore, was applied in a layer thickness of 20 g / m 2 and under a system from Energy Science, Burlington, Mass., USA, with the type Elektrocurtain® CB 150/1515 with nitrogen irradiated with a radiation dose of 1.5 Mrad. The finished effect film coated in this way is glued to a chipboard at 70 or 130 ° C under a pressure of 0.4-0.6 N / mm2.

Example 11

With the impregnation solution described in Example 10, a rosewood decor paper (90 g / m2) with a resin application of 80% b.a. Soaked paper weight and dried back at 160 ° C to a residual moisture of approx. 8%. The paint spread and the sticking of the finished effect film are carried out under the same conditions as in Example 10.

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Comparative Tests on Examples 10 and 11 The elastic base films described in Examples 10 and 11 are produced.

As a paint spread, however, a conventional acid-curing paint consisting of 80 parts of hexamethoxymethyl melamine, 20 parts of a branched polyether containing hydroxyl groups and an OH number of approx. 380 (viscosity at 25 ° C = 650 ± 100 mPas), 10 parts of a silicate Matting agent (eg matting agent OK 412 from Degussa) and 20 parts of half-concentrated hydrochloric acid. The application amount is 20 g / m2 (dry). Curing takes place at 100 ° C for 1 min.

The finished effect films obtained in this way are again stuck at 70 and 130 ° C. under a pressure of 0.4-0.6 N / mm 2.

s Assessment of the according to Examples 10 and 11 and

Comparative tests on manufactured panels The surface was tested in accordance with technical delivery conditions TL 7 100-001, edition 3 of the Federal Office of Defense Technology and Procurement. The results are summarized in Table 2.

Assessment = 0 = best grade

5 = worst grade

Table 2

exam

Sheets according to Example 10 70 ° C 130 ° C

according to Example 11 70 ° C 130 ° C

Comparative experiment example 10 70 ° C 130 ° C

Comparative experiment Example 11 70 ° C 130 ° C

Unity

0

0

0

0

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4th

visual assessment of the

surface

0

0

0

0

3rd

5

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5

Water resistance

0

0

0

0

1

1

1

1

Resistance to alcohol

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0

4th

0

4th

0

4th

0

Resistance to soda

0

0

0

0

0

0

0

0

Cooking test

0/0

0/0

0/0

0/0

1/2

0/0

1/2

0/0

Heat resistance

0

0

0

0

0

0

0

0

Resistance to embers

0

0

0

0

1

1

1

1

In addition to the procedural and economic advantages of the coating composition according to the invention already described above, it can be seen from Table 2 that even when the coating is laminated on at a low temperature, at least the surface resistances equal to those of the conventional lacquers are obtained. The uniformity of the surface and the complete closedness of the coating are particularly advantageous.

Example 12

A walnut decor paper (30 g / m2) is pre-impregnated with a customarily curable melamine-formaldehyde condensate (e.g. ®Kauramin impregnating resin 780 liquid + 0.4% of an ammonium salt, e.g. hardener 527 liquid) with approx. 80% resin application. The coating was then applied to the still wet film using a coating composition prepared in accordance with Example 1, which instead of the melamine / formaldehyde resin contains a urea / formaldehyde resin but no photoinitiator, under the same conditions as in Example 10.

This film is laminated onto a chipboard at 140 ° C within 1 min under a pressure of 1.2 N / mm2.

The quality inspection carried out in accordance with Table 2

fung gives the following values:

Unity 0

visual assessment of the surface 0

Water resistance 0

Alkali resistance 0

Resistance to soda 0

Cooking sample 0/0

Heat resistance 0

Ember resistance 0

35 This procedure cannot be carried out with conventional paint. Another advantage of this film is that it is particularly easy to structure due to its high elasticity.

40 Example 13

A rosewood decorative paper (90 g / m2) is pre-impregnated as in Example 12 with a commercial melamine resin with 80% resin application and pre-dried at 160 ° C (residual moisture: 6%).

45 The subsequent painting was carried out as described in Example 10, the lamination as described in Example 12.

The surface quality check gives the following values:

Unity 0

50 visual assessment of the surface 0

Water resistance 0

Alkali resistance 0

Resistance to soda 0

Cooking sample 0/0

55 heat resistance 0

Ember resistance 0

The surface obtained is characterized by very good consistency, uniformity and high resistance.

Even lamination of this film after air-conditioning (15 h / 70 ° C) does not change the film elasticity or the surface properties.

s

Claims (6)

627 096 1. Process for the production of coatings or cover layers on substrates by curing a coating composition which contains polymerizable binders with the aid of light with a wavelength of 200 to 500 nm or electron beams with an energy between 50 and 500 KeV, characterized in that a coating composition, containing: A. 99.9 to 20% by weight of a reaction product from a) optionally completely or partially etherified amine / formaldehyde condensates and b) (meth) acrylic compounds containing hydroxyl or amino groups, 1/3 to 1 mol of the acrylic compound being used on one equivalent of CH2-0 group of the amine / form aldehyde condensate, B. 0 to 60 wt .-% of liquid, room temperature liquid, copolyme-risierbar, organic compounds, E. 0 to 50 wt .-% of other polymerizable unsaturated Binder, used. 2. The method according to claim 1, characterized in that one uses a component A, which was prepared by reacting the amine / formaldehyde condensates a) with the hydroxyl or amino groups containing acrylic or methacrylic compounds b) in the presence of c) an organic or inorganic acid with a pK value of <3.0 as a catalyst. 2nd PATENT CLAIMS 3. The method according to claim 1 or 2, characterized in that one applies the coating composition to one side of a flat intermediate carrier, which can be glued to the substrate to be coated using heat and / or pressure, cures and the other side of the one-sided coating Intermediate carrier glued to the substrate. 4. The method according to any one of the preceding claims, characterized in that a coating composition containing C. 0 to 80 wt .-% pigments or fillers is used. 5. The method according to any one of the preceding claims, characterized in that one uses a coating composition containing D. 0 to 20 wt .-% of other organic coating aids. 6. The method according to any one of the preceding claims, characterized in that one uses a coating composition containing F. 0.1 to 20 wt .-% of a photoinitiator system.