KR970004600B1 - UV Curing Coating Composition and Method for Manufacturing Urethane Modified Epoxy Acrylate Oligomer - Google Patents

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Description

UV Curing Coating Composition and Method for Manufacturing Urethane Modified Epoxy Acrylate Oligomer

The present invention relates to an ultraviolet curable coating film composition, and in particular, aesthetics of a molded article by coating on a plastic molded article such as polymethyl methacrylate, polycarbonate, polystyrene, styrene-acrylonitrile, polyester, acrylonitrile-butadiene-styrene, The present invention relates to an ultraviolet curable coating film composition containing a urethane-modified epoxy acrylate oligomer used for the purpose of increasing durability.

Most of these molded products have been used as a substitute for glass, and its use is increasing because of its excellent gloss and impact resistance and easy processing. However, these molded articles tend to have a weak surface wear resistance, scratch resistance, solvent resistance, and the like.

Thus, attempts to remedy these defects have long been in progress. Silicone resins and melamine resins are mainly used for this purpose, and these are thermosetting, which requires exposure to heat for a long time in order to form a coating film, so that the heating time is long and the yield decreases, and the high temperature affects the physical properties of the molded polymer material. Get mad. U.S. Patent Nos. 4,273,802, 4,397,723, 4,557,975, 4,617,194 and the like describe an ultraviolet curable coating composition using an acrylate oligomer containing two acryloyloxy groups in order to improve the problems of the above-mentioned thermosetting paints. It is.

In particular, US Pat. No. 4,617,194 discloses acrylic methacrylate monomers of aliphatic polyols containing at least three acryloyloxy or methacryloyloxy and bisphenols containing at least four acryloyloxy or methacryloyloxy. -UV curable varnishes prepared using acrylic or methacrylic ester resins of polyglycidyl ethers of a formaldehyde condensate are described, but these varnishes have properties such as abrasion resistance, scratch resistance, and weather resistance (yellowing resistance) of the cured product. There was a downside to this somewhat.

It is an object of the present invention to provide a UV-curable coating composition for plastics processing which overcomes these shortcomings and is excellent in curability, wear resistance, weather resistance, adhesion and scratch resistance.

The object of the present invention described above is achieved by a composition obtained by combining urethane-modified epoxy acrylate with bisphenol A-type epoxy acrylate, if necessary, as a reactive oligomer and blending a reactive monomer, photoinitiator, leveling agent and other additives.

As the reactive oligomer used in the present invention, the urethane-modified epoxy acrylate of the general formula (I) may be used alone or in a mixture with the bisphenol A type epoxy acrylate of the general formula (II).

R ¹ in the general formula (I) is an aliphatic, cyclic aliphatic or aromatic compound.

The urethane-modified epoxy acrylate oligomer used in the present invention is compensated for by the introduction of urethane groups such as weather resistance defects, which are disadvantages of general epoxy acrylates, cracks in coatings due to curing shrinkage during curing, and poor adhesion to the substrate. The above-mentioned properties appearing in the coating film are improved. That is, urethane-modified epoxy acrylate has high strength, excellent scratch resistance, fast curing speed, and flexibility, elasticity, adhesion, and strong weather resistance of urethane bonds due to the introduction of epoxy groups.

The urethane-modified epoxy acrylate oligomer of the general formula (I) is prepared by addition reaction of the hydroxyl group of the bisphenol A-type epoxy acrylate of the general formula (II) with a functional group (NCO) of aliphatic, cyclic aliphatic or aromatic diisocyanate. The urethane acrylate oligomer of the general formula (I) may be used alone or in combination with bisphenol A-type acrylate, the amount of which may be used 10-80% by weight of the total composition. When the urethane acrylate of the general formula (I) is mixed with the bisphenol A-type epoxy acrylate of the general formula (II), it may be used in a weight ratio of 1 / 9-10 / 0. In particular, when using a mixed oligomer, it is useful to react with the functional group of diisocyanate at less than 1/2 of the hydroxyl group equivalent of General formula (II). That is, the mixing ratio of the urethane-modified epoxy acrylate and the bisphenol A-type epoxy acrylate can be adjusted according to the equivalent ratio control of the diisocyanate and the bisphenol A-type epoxy acrylate. In particular, when the functional group number of the diisocyanate exceeds 1/2 of the hydroxy group equivalent of the general formula (II), it is preferable to avoid the risk of gel formation during the reaction.

Diisocyanates used in the preparation of such urethane-modified epoxy acrylate oligomers include isophorone diisocyanate (3-isocyanate methyl 3,5,5-trimethyl cyclohexyl isocyanate), 4,4'-dicyclohexylmethane-diisocyanate , Trimethylhexamethylene-diisocyanate, 1,6-hexamethylene diisocyanate, 2,4,4-trimethyl 1,6-hexamethylene diisocyanate, octadecylene diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and the like, and most suitable for the UV curable coating composition for double sheets is 3-isocyanate methyl 3,5,5-trimethylcyclohexyl isocyanate or 4,4 ' -Cyclohexylmethane-diisocyanate.

The reactive monomer of the present invention is polymerized with the oligomer to affect the physical properties of the coating film. Reactive monomers may be one or more monomers, which are typically acrylic ester monomers, which are prepared by esterifying an alcohol with an unsaturated carboxylic acid, 1,3-butanediol diacrylate, 1,4-butanedioldi Acrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, neopentylene glycol diacrylate, ethylene glycol diacrylate, tetraethylene glycol dimethacrylate, Polyethylene glycol dimethacrylate, tripropylene glycol diacrylate, pentaerythritol tetraacrylate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, pentaerythritol triacrylate, and the like. have.

Considering the physical properties and economics of the coating film, as the reactive monomer, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, trimethylol propane triacrylate, pentaerythritol tetraacrylate, and the like are usefully used. The amount of the varnish composition may be used in an amount of 10 to 80% by weight, but it is preferable to use 20 to 60% by weight in consideration of viscosity and the like.

The photoinitiator uses a conventional polymerization initiator which is activated by ultraviolet rays, and 0.5 to 10% by weight of compounds such as bezophenone series, benzyldimethyl ketal series, acetophenone series, anthraquinone series, and thioxanthone series are used. do. Particularly representative of such photoinitiators are hydroxycyclohexyl phenylketone, 2,2-dimethoxy2-phenyl acetophenone, benzophenone, phenyl-2-hydroxy-2-propylketone.

The leveling agent uses a silicone diacrylate-based or silicone polyacrylate-based compound in an amount of 0.1 to 5% by weight of the whole varnish composition.

The painting work on the plastic molded article is spraying, dipping, placoating, etc., which can be advantageously selected depending on the material of the plastic, the shape of the molded article, the coating thickness, and the like.

Depending on the coating method, a volatile diluent may be added and adjusted to an appropriate viscosity.

In addition, the volatile diluent increases the adhesion of the coating film by giving a chemical impact on the surface of the plastic molded part before curing during painting. Diluents that can be used include ketones, alcohols, acetates, aromatic compounds, etc. These may be used in combination of one or more, and the amount of the varnish / diluent weight ratio is 4/1/1/3 can be used.

Other additives can use a well-known compound by changing the addition amount according to various requirements.

Hereinafter, the preparation method and the effect of the present invention will be described in detail through Examples and Comparative Examples. However, the following examples do not limit the scope of the present invention.

Example 1

Urethane-modified epoxy acrylates prepared by reacting 1 equivalent of bisphenol A-type epoxy acrylate and 0.1 equivalent of isoprone diisocyanate by addition reaction of R8828 (Bisphenol-type epoxy resin of Korea Chemical, Epoxy equivalent: 184 ~ 194) with acrylic acid 30 Parts by weight, 10 parts by weight of trimethylolpropane triacrylate, 6.5 parts by weight of 1,6-hexanediol diacrylate, 3 parts by weight of 2,2-dimethoxy-2-phenyl acetophenone, silicone polyacrylate Evercryl 1360) of 0.5 parts by weight, methyl ethyl ketone 30 parts by weight and 20 parts by weight of isopropyl alcohol at 20 ~ 30 ℃ stirred to make an ultraviolet curable varnish.

Example 2

An ultraviolet curable varnish was prepared in the same composition and content as in Example 1 using a urethane-modified epoxy acrylate prepared in Example 1 using an urethane-modified epoxy acrylate prepared in an equivalent amount of isopron diisocyanate at 0.2 equivalent.

Example 3

An ultraviolet curable varnish was prepared in the same composition and content as in Example 1 using a urethane-modified epoxy acrylate prepared in Example 1 with an equivalent of 0.3 equivalent of isopron diisocyanate in preparing the urethane-modified epoxy acrylate.

Comparative Example 1

A UV curable varnish was prepared with the same composition and content as in Example 1 except that the bisphenol A-type epoxy acrylate of Example 1 was used alone without using a urethane-modified epoxy acrylate as the reactive oligomer.

TABLE 1

※ ◎: Most Good ○: Good △: No

※ Curing condition: 80 watts / cm, 2 light irradiation distance 10cm

※ Dry film thickness: 7 ~ 10㎛

※ ABS: Acrylonitrole Butadiene-Styrene

※ PC: Polycarbonate

* 1) Measured according to JIS D0202 (Cross-Cut)

* 2) Measured according to JIS D0202 (cross-cut)

* 3) Measured according to JIS D0202 (Uni-pencil used)

* 4) Discoloration observation after sunlight × 7 days

* 5) BYK's Dual-O-meter

* 6) Room temperature after 24 hours deposition

* 7) Use of dual abrasion tester (model 505) (weight mg loss)

Claims (8)

10 to 80% by weight of reactive oligomer comprising urethane-modified epoxy acrylate of formula (I), 10 to 80% by weight of reactive monomer, 0.5 to 10% by weight of photoinitiator, 0.01 to 1% by weight of leveling agent and other additives Photocurable coating film composition, characterized in that. Wherein R ¹ is an aliphatic, cycloaliphatic or aromatic compound. The method of claim 1, wherein the reactive monomer is trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, tripropylene glycol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, tripropylene glycol Photocurable coating composition, characterized in that selected from triacrylate, tripropylene glycol diacrylate and neopentyl glycol diacrylate. The photocurable coating composition according to claim 1, wherein the photoinitiator is selected from benzophenone, benzyldimethyl ketal, acetophenone, anthraquinone and thioxanthone. The photocurable coating composition according to claim 1, wherein the leveling agent is selected from silicone diacrylates, silicone polyacrylates, and polysiloxanes. The photocurable coating composition of claim 1, wherein the reactive oligomer comprises a bisphenol-A epoxy acrylate of Formula (II) together with the urethane-modified epoxy acrylate of Formula (I). The urethane modified epoxy acrylate oligomer represented by the following general formula (I) characterized by addition-reacting the hydroxyl group of the phenol phenol type epoxy acrylate of the following general formula (II) with the functional group of aliphatic, cyclic aliphatic, or aromatic diisocyanate. Manufacturing method. Wherein R ¹ is an aliphatic, cyclic aliphatic or aromatic compound. 7. A process according to claim 6, characterized in that it is reacted with less than 1/2 equivalents of diisocyanate equivalent of the hydroxyl group equivalent of bisphenol A type epoxy acrylate. The diisocyanate according to claim 6, wherein the diisocyanate is isophorone diisocyanate (3-isocyanate methyl 3,5,5-trimethylcyclohexyl isocyanate) 4,4'-dihexoxylmethane-diisocyanate, trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,4,4-trimethyl 1,6-hexamethylene diisocyanate, octadecylene diisocyanate, 1,4-cyclohexylene diisocyanate, 2,4-toluene diisocyanate, And 2,6-toluene diisocyanate.