DE2636426A1 - Thermally or radiation curable coating compsn. - contg. reaction prod. of vinyl isocyanate and unsaturated hydroxy-carboxylic acid, for printing and varnishing - Google Patents

Abstract

A hardenable coating compsn. contains a binder comprising a cpd (A) with olefinic unsaturation and urethane gps. and opt. an unsatd. cpd. (B) copolymerisable with (A) but differing from it., (A) is the reactn. prod. of vinyl isocyanate and a cpd. contg. OH gp(s) and the residue of an ester of a 3-6C carboxylic acid with alpha, beta-unsatn. Used in printing inks and (protective) varnishes for e.g. metals, wood, plastics, leather or paper. The compsn. can be cured by heating opt. in presence of initiators (e.g. organic peroxides) and accelerators (e.g. Co salts) or pref. by irradiation with UV or electron beams. The compsn. dries rapidly and adheres well partic. to metals.

Description

Hardenable coating compound

The invention relates to a curable coating composition used as a binder forming component contains a vinyl urethane, which by reaction of at least one an ester of an unsaturated carboxylic acid containing a free hydroxyl group Vinyl isocyanate has been obtained from solutions of high or low molecular weight coating agents unsaturated compounds in vinyl monomers are known. Quickly when used copolymerizable vinyl compounds such as acrylic compounds can include such Systems are cured with high-energy rays. Acrylic compounds have however the disadvantage that they are generally toxic and lead to severe skin irritation.

From DT-OS 20 64 701.2-43 a process for the production of coatings by curing olefinically unsaturated urethane-containing polymeric substances, which, optionally in a mixture with olefinically unsaturated monomeric compounds, are cured by means of ionizing radiation, is known, the olefinic unsaturated polymeric substance containing urethane groups at least two Contains units and has been obtained by reacting hydroxyl-containing oligomers or polymers having a molecular weight between 500 and 10,000 with vinyl isocyanate. However, these products still need to be improved in terms of reactivity and hardness. The object of the present invention was therefore to provide coating compositions which are further improved with regard to these properties and also have the advantage of being curable also by UV radiation and peroxides and, surprisingly, this object could be achieved in an advantageous manner with the coating compositions according to the present invention to solve. The present invention relates to a curable coating composition which, as a binder-forming component, optionally in a mixture with at least one at least one at least mono-olefinically unsaturated compound with a molecular weight between 70 and 20,000 and a boiling point above 50 ° C (A) is a vinyl urethane different from (A) (B), which is characterized in that the vinyl urethane (B) is a reaction product of an ester containing at least one free hydroxyl group of a 4, β-olefinically unsaturated carboxylic acid containing 3 to 6 carbon atoms with vinyl isocyanate.

One of the structural components of the coating compositions according to the invention is to carry out the following in detail.

(A) The optionally in combination with the vinyl urethane according to the invention (B) to be used olefinically unsaturated compound A should have a boiling point above of 500C, preferably above 100 ° C. Lower boiling compounds are generally less suitable because they are after application of the coating and Evaporate too easily before they harden. On the one hand, this can cause the composition to evaporate the coating mass change, on the other hand this can pollute the environment with odorous and sometimes toxic monomers lead to environmentally friendly Paints and printing inks are therefore compounds with a vapor pressure of less than about 10 torr at 1000C particularly preferred. The molecular weight of the component A can vary within wide limits between 70 and 20,000, i.e. both low and high molecular weight compounds are used.

Possible examples include: 1. Esters of unsaturated mono- or dicarboxylic acids, e.g.

Esters of acrylic, methacrylic, $ cyanoacrylic, croton, cinnamon, sorbin, Maleic, fumaric or itaconic acid with aliphatic, cycloaliphatic or aromatic aliphatic a- to tetravalent alcohols with 3 to 20 carbon atoms, e.g. methyl (meth) acrylate, n-, i- and t-butyl (meth) acrylate, 2-ethylhexyl acrylate, lauryl acrylate, dihydrodicyclopentadienyl (meth) acrylate, Methyl glycol acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, ethylene glycol diacrylate, Diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol di (meth) acrylate, 1,4-dimethylolcyclohexanediacrylate, pentaerythritol tri and tetra (meth) acrylate, ethyl dcyanoacrylate, Ethyl crotonate, ethyl sorbinate, diethyl maleate, diethyl fumarate and di (meth) acrylate of the alkoxylated bisphenol Ao 2. Amides of acrylic acid or methacrylic acid, the optionally on the nitrogen atom with alkyl, alkoxyalkyl or hydroxyalkyl radicals may be substituted, e.g. N, N'-dimethylacrylamide, N-isobutyl acrylamide, diacetone acrylamide, N-methylolacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide, N-butoxymethyl methacrylamide, Ethylene glycol bis (N-methylolacrylamide) ether.

3. vinyl esters of mono- or dicarboxylic acids with 2 to 20 carbon atoms, zoBo vinyl acetate, vinyl propionate, 2-ethylhexanoic acid vinyl ester, Versatic acid vinyl ester, Divinyl adipate, etc., 4. Vinyl ethers of monohydric or dihydric alcohols with 3 to 20 carbon atoms, e.g. Isobutyl vinyl ether, hexyl vinyl ether, octadecyl vinyl ether, Ethylene glycol divinyl ether, diethylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether 5. Mono-N-vinyl compounds, zoBo N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylmorpholinone, N-vinyloxazolidone, N-vinylsuccinimide, N-methyl-N-vinylformamide, N-vinylcarbazole and DivinyXurea.

6. Styrene and its derivatives, e.g. oN-methylstyrene, 4-chlorostyrene or 1,4-divinylbenzene 7.Allyl ethers and esters, e.g. trimethylolpropane diallyl ether, Trimethylolpropane triallyl ether, pentaerythritol triallyl ether, diallyl maleate, diallyl fumarate or Diallylphthalat0 8. unsaturated polyester with a molecular weight between 500 and 5000 and 0.5 to 10 double bonds per 1000 molecular weight units, for example made from a) 10 to 70 percent by weight oS, R-unsaturated dicarboxylic acid, such as maleic acid, fumaric acid or itaconic acid, b) 0 to 60 percent by weight saturated aliphatic, cycloaliphatic or aromatic dicarboxylic acids, such as succinic acid, Adipic acid, tetrahydrophthalic acid, hexahydrophthalic acid, cyclohexane-1,4-dicarboxylic acid, Phthalic acid, isophthalic acid or terephthalic acid, c) 20 to 80 percent by weight of aliphatic, cycloaliphatic or non-phenolic aromatic diols, such as ethylene glycol, Diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butene-2-diol, neopentyl glycol, 1,6-hexanediol or oxyalkylated bisphenol As d) 0 to 5 percent by weight tri- or tetracarboxylic acids, such as trimellitic acid, pyromellitic acid or benzene tetracarboxylic acid, e) 0 to 10 percent by weight of monocarboxylic acids, such as acetic acid, propionic acid or benzoic acid, f) 0 to 5 percent by weight of tri- or tetrafunctional alcohols, such as glycerol, trimethylolpropane or pentaerythritol, g) 0 to 10 percent by weight of monofunctional alcohols, such as Methanol, ethanol, propanol or butanol.

9. Unsaturated epoxy resins made for example from a) monofunctional epoxides and (meth) acrylic acid according to US Pat. No. 2,484,487, b) bifunctional epoxides and unsaturated fatty acids according to US Pat. No. 2,456,408, c) polyfunctional aromatic epoxides and crotonic acid according to US Pat. No. 2,575,440 or d) polyfunctional aromatic or aliphatic glycidic ethers and (meth) acrylic acid according to US-PS 2 824 851.

10. Unsaturated polyurethanes made from hydroxyalkyl acrylates, diisocyanates and optionally polyols or polyamines such as e.g. saturated or unsaturated Polyester polyols, polyether polyols or copolymer polyols, such as those described in, for example DT-OS 1 644 797 or for printing inks in DT-OS 2 358 948 are described.

11. Unsaturated copolymers, zoBo produced by reacting a) Copolymers containing maleic anhydride groups with unsaturated alcohols, for example according to DT-OS 2 050 893 or b) containing carboxylic acid groups Acrylic ester copolymers or polyesters with unsaturated epoxides e.g. glycidyl acrylate0 12. Butadiene polymers in which the double bonds are predominantly pendent Vinyl groups are present.

13. Diallyl phthalate prepolymers.

14. Poly-N-vinyl urethanes, e.g. produced according to DT-OS 2 064 701 by reacting vinyl isocyanate with saturated or unsaturated polyester polyols, Polyether polyols or polyfunctional alcohols.

Mixtures of the various unsaturated Compounds A can be used.

(B) The vinyl urethane (B) to be used according to the invention is they are reaction products containing at least one free hydroxyl group Esters of o (,, ß-olefinically unsaturated carboxylic acids containing 3-6 carbon atoms with vinyl isocyanate. As ester containing 3 - 6 carbon atoms o (,, ß-olefinic unsaturated carboxylic acids with one or more free hydroxyl groups that act as As a structural component of the vinyl urethanes, the esters are o>, ß-olefinically unsaturated Monocarboxylic acids, such as acrylic acid, methacrylic acid, oU-cyanoacrylic acid with two or higher-valent alcohols, such as straight-chain, branched or cycloaliphatic Diols or oxaalkanediols with up to 12 carbon atoms, such as ethylene glycol, 1,2- and 1,3-propylene glycol, butanediol-1,4, -1,3 and -1,2, pentanediol, hexanediol, Diethylene glycol, triethylene glycol, Dipropylene glycol, dibutylene glycol, Cyclohexanediol, triols such as glycerine, trimethylolpropane, tris (hydroxyethyl) isocyanurate as well as higher alcohols such as

Pentaerythritol, dipentaerythritol, sorbitol, mannitol, these being esters must contain at least one free hydroxyl group. Preferred suitable Hydroxy esters are, for example, alkylene glycol monoacrylate, propanediol monoacrylate, butanediol monoacrylate as well as epoxy acrylates from glycidyl ethers of mono- and polyfunctional alcohols or Phenols or from glycidyl esters of aliphatic, cycloaliphatic and aromatic Mono- and polycarboxylic acids and from singly or multiply epoxidized or cycloaliphatic acids Hydrocarbons.

The reaction of these hydroxyesters with vinyl isocyanate takes place in a known manner Way, preferably in the presence of tin compounds as a catalyst or of inert Solvents, with generally approximately equivalent amounts of isocyanate groups be reacted with the free hydroxyl groups of the hydroxy esters. Will however Hydroxy esters with more than one free hydroxyl group for reaction with vinyl isocyanate brought, it is sufficient in each case 1 mole of vinyl isocyanate with 1 mole of the hydroxy ester to implement. Preference is given to vinyl urethanes made from hydroxypropyl acrylate, hydroxyl butyl acrylate, Hydroxyethyl acrylate and low-viscosity epoxy acrylates, e.g. the addition product of 2 moles of acrylic acid to 1 mole of butanediol diglycidyl ether.

Component (B) can serve as the sole binder.

To achieve certain effects, e.g. for a special application Properties to be matched, it is often expedient in many cases to use the vinyl urethane to be combined with component (A). For this purpose, the vinyl urethane with up to 95, preferably 70 percent by weight of component (A) can be combined.

The coating composition according to the invention can, depending on the intended use contain the relevant additives, for example: 1. 0 up to 70, preferably 10 to 50 percent by weight of inorganic or organic pigments, e.g. soot, titanium dioxide, chalk, barite, zinc white, lithopone, chrome yellow, iron oxide yellow or complex pigment dyes, such as phthalocyanines, azo pigments, anthraquinone dyes, Quinacridone pigments, 2. 0 to 10, preferably 0.001 to 3 percent by weight of dyes, for example eosin, crystal violet, malachite green, 3. 0 to 10, preferably 1 up to 5 percent by weight leveling agent, e.g. B. butyl acetate, butanol, silicones or diluents, 4. 0 to 1, preferably 0.001 to 0.5 percent by weight of inhibitors, 5. 0 to 70, preferably 10 to 50 percent by weight fillers, 6. 0 to 10, preferably 1 to 5 percent by weight of diluent, 7. 0 to 70, preferably 10 to 50 percent by weight inert synthetic resins, e.g. aminoplasts, alkyd resins, 8.0 to 7, preferably 0.5 to 5 percent by weight of waxes, 9. 0 to 5, preferably 0.2 to 5 percent by weight of thixotropic agents.

The coating compositions according to the invention are cured by polymerization of the vinyl urethane (B) or by copolymerization of components (A) and (B), these Polymerization can be thermal, by direct heating, or by means of IR rays with the help of Initiators, but preferably by high-energy Rays take place.

In the case of thermal polymerization, temperatures between 20 and 2000C applied; the usual initiators, such as organic Peroxides or azo compounds, as well as accelerators, such as cobalt salts, ih amounts of 0.5 to 6 percent by weight can be added.

Radiation curing can be done with UV rays or electron beams take place. In the case of UV irradiation, customary photoinitiators are added like them e.g. B.J. Kosar in 'Light Sensitive Systems ", Wiley, 1965, pp. 158-193 Has. The following are preferably used: Benzoin, benzoin ether, diacetyl, benzil, benzil monoketals, Benzophenone, Michler's ketone, yanthones, anthraquinones, sulfur compounds, such as Disulfides, thiols, dithiocarbamates, or carbonyl compounds such as triphenylphosphine iron tetracarbonyl in connection with substances that split off chlorine, each in amounts of 1 to 3 percent by weight. Details of the method of curing with UV rays can be found in the article "Photopolymerization" by H. Barzynski, K. P enzien and 0. Volkert in Chemiker-Zeitung 96 (1972), pages 545 to 551, and in DT-OS 2 251 933. Die electron beam hardening is described in detail in DT-OS 2 049 715 already cited. Find there there is also more detailed information on favorable layer thicknesses, radiation doses and radiation duration.

The coating compositions according to the invention are suitable for the production of Coatings and lacquers on metals, wood, plastic, leather and paper. These coatings can serve as protective layers or for decorative purposes.

The coating compounds can also be used as a photopolymer layer for print media, such as relief or planographic printing plates, or for photoresists. The curing takes place here by imagewise irradiation of the coated carrier; on the unexposed There is no hardening, this Parts of the layer are removed again.

Finally, the coating compositions can also be used for the production of UV-curing Printing inks and printing pastes are used.

Carrier materials such as paper, metals or plastic films are used here printed with pigment-containing binders in layer thicknesses of about 0.5 to 5 μm. With UV radiation, the binders harden very quickly and the color becomes fixed on the carrier material. Those produced with the coating compositions according to the invention Printing inks are characterized by extremely fast drying when using only 1 to 2 UV lamps off in four-color printing and at maximum printing speed. the drying prints have a very good shear strength. This is for colors which are particularly critical in UV printing in this regard (such as blue and black), Greatly improved compared to comparable UV printing inks. This is especially true for Printing with the highest printing speeds and thus minimal exposure times were manufactured.

Without the addition of pigments, the binders can be used as overprint varnishes be used.

The use of the coating compositions according to the invention is particularly advantageous for printing inks and overprint varnishes.

The parts and percentages described in the example relate on weight.

Example 148 parts of butanediol monoacrylate are dissolved in 200 parts of ethyl acetate solved. 0.08 part of dibutyltin dilaurate is added and the mixture is added dropwise at 50 with stirring up to 60 ° C. 69 parts of vinyl isocyanate. The reaction is allowed to continue for 1-2 hours until the isocyanate content has fallen below 0.1%. 0.2 parts of hydroquinone methyl ether are then added to and the solvent is removed in vacuo. A pale greenish-yellow color is obtained colored liquid (yield practically quantitative).

A solution is made from the following components: 64 parts of one Addition product of 2 moles of acrylic acid to 1 mole of bisphenol A diglycidyl ether (double bond value 0.38 eq / 100 g), 16 parts of butanediol-1,4-diacrylate and 20 parts of the above reaction product.

This solution is applied to chipboard in a layer thickness of 60 Xum and with 320 Kv electrons at a belt speed of Cured 80 m / minute corresponding to a radiation dose of 0.875 Mrad. You get a scratch-resistant, non-sticky coating of high hardness (pendulum hardness according to König 200 Seconds).

Claims (1)

Patent claim Curable coating composition, which forms as a binder Component, optionally mixed with at least one at least one olefinic component unsaturated compound with a molecular weight between 70 and 20,000 and one Boiling point above 50 0C (A) contains a vinyl urethane (B) different from (A), characterized in that the vinyl urethane (B) is a reaction product of at least one an ester containing a free hydroxyl group of a 3-6 carbon atom i, R-olefinically unsaturated carboxylic acid with vinyl isocyanate.