KR0154868B1 - The method of preparation for urethane acrylate digomer and ultraviolet rays -hardening coating composition - Google Patents

Abstract

The urethane acrylate oligomers of formula (I) are prepared by reacting polyols, polyester polyols and polysiloxanes with one functional group of the diisocyanate and an acrylate having a hydroxyl group at the end of the other functional group of the diisocyanate. The ultraviolet curable coating composition of the present invention includes a urethane acrylate oligomer, a reactive monomer, a photoinitiator, a silicone-based leveling agent, and other additives of general formula (I). This UV curable coating film composition generates glass-like siloxane bonds in the coating film by the siloxane groups contained in the oligomer, so that the coating film is beautiful and durable when coated on a polycarbonate molded article.

In the above formula, X is an acrylate main chain represented by the following general formula (II), R ¹ is an aliphatic, cyclic aliphatic or aromatic compound, and Y is a main chain of polyol, polyester polyol and polysiloxane.

Description

Urethane acrylate oligomer manufacturing method and ultraviolet curable coating composition containing this oligomer

The present invention relates to an ultraviolet curable coating composition, and in particular, coated on plastic molded products, such as polymelt methacrylate, polycarbonate, polystyrene, styrene acrylonitrile, polyester, acrylonitrile-butadiene styrene, etc. It relates to an ultraviolet curable coating film composition used for the purpose of increasing the In particular, the present invention is usefully used as an ultraviolet curable coating film composition which is coated on a polycarbonate molded article for a head lamp to exhibit improved scratch resistance.

Most of these moldings have been used as a substitute for glass, and the amount of use is increasing because of its ease of processing in addition to excellent performance in its gloss and impact resistance. However, these molded products 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 thermosets, which need to be exposed to heat for a long time in order to form a coating film, resulting in low yields due to prolonged heating and high physical properties of the molded polymer material. Will fall out. In order to solve this problem of thermosetting paints, U.S. Patent Nos. 4,273,802, 4,397,723, 4,557,975, and 4,617,194 disclose UV-curable coating compositions containing two acryloyloxy groups.

In particular, US Pat. No. 4,617,194 discloses acrylic or methacrylic ester 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 condensates have been described, which have abrasion resistance, scratch resistance and weather resistance (yellowing resistance) of the resulting coatings. There was a disadvantage in that the physical properties of the back slightly.

It is an object of the present invention to provide a UV-curable coating composition for plastic processing, which is particularly excellent in scratch resistance and which is remarkable.

The above object of the present invention is achieved by the composition of the present invention composed of reactive oligomers, reactive monomers, photoinitiators, leveling agents, additives and the like prepared using polysiloxane compounds.

The present invention will be described in detail as follows.

The present invention adds and reacts cyclic aliphatic or aromatic diisocyanates to a mixture composed of polyols, polyester polyols, and polysiloxanes such that the polyols, polyester polyols, and polysiloxanes each bind to one functional group, NCO, in the diisocyanate. To the reaction product was added an acrylate of general formula (II) containing a hydroxyl group at the end, and the remaining isocyanate functional group of the diisocyanate of polyol, polyester polyol and polysiloxane bonded to the general formula (II) described above. It is composed of a method of producing a urethane acrylate oligomer having excellent scratch resistance represented by the following general formula (I) suitable for use in the photocurable coating composition by addition reaction so that the acrylate of).

In the above formula, X is an acrylate main chain represented by the following general formula (II), R ¹ is an aliphatic, cyclic aliphatic or aromatic compound, and Y is one of the main chains of polyol, polyester polyol and polysiloxane.

In the above formula, R ₂ is hydrogen or methyl group, R ₃ is an alkylene group having 1-12 carbon atoms.

The polyol used in the preparation of the urethane acrylate oligomer of the general formula (I) is polytetrahydrofuran (PTHF) having a molecular weight of 500-3000 represented by the following general formula (III). Representative of such polyols include the PRHF-650, PTHF-2000, etc. of the BASF Co., Ltd., among which, when using PTHF-1000 or PTHF-2000, scratch resistance tends to be somewhat inferior PTHF-650 is preferably used.

Wherein m is an integer of 6-42.

The polyester polyol used in the preparation of the urethane acrylate oligomer of the general formula (I) is a substance represented by the following general formula (IV), which can be obtained by the condensation reaction of an acid having two carboxyl groups and an alcohol having two hydroxyl groups. In consideration of the hardness of the cured coating film and the like, it is preferable to use a polyester polyol having a hydroxyl group of 200-250 and a molecular weight of 450-560.

In the above formula, R ⁴ is an aliphatic, cyclic aliphatic or aromatic compound having ² to 10 carbon atoms, R ⁵ is an aliphatic, cyclic aliphatic or aromatic compound having ² to 10 carbon atoms, and n is an integer of 1-3.

Acids with two carboxyl groups used in the preparation of the polyester polyester polyols described above include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, maleic acid, terephthalic acid and the like. Diethylene glycol, neopentylene glycol, and the like.

Polysiloxane used for manufacture of the urethane oligomer of the said general formula (I) is a substance which has the molecular weight 50-1000 represented by the following general formula (V). The representative examples of such polysiloxanes include Shinwol Corporation's trade names KF-6001, KF-6002, and KF-6003. However, KF-6002 and KF-6003 have low varnish viscosity and somewhat low scratch resistance. desirable.

Wherein R ⁶ and R ⁷ are alkyl, haloalkyl, cyanoalkyl or alkenyl and k is an integer from 1-18.

The polyols, polyester polyols and polysiloxanes used in the reaction with the diisocyanate are mixed in a weight ratio of 5-90 / 5-90 / 5-90, and the weight ratio is 25-35 considering the hardness and physical properties of the coating film. It is preferable to make it to / 25-35 / 30-50.

As described above, when a mixture of polyol, polyester polyol, and polysiloxane is used as the urethane oligomer, unlike a conventional pure urethane oligomer, a polysiloxane-specific Si-O bond causes a glass-like siloxane bond to the urethane structure. Since the slip resistance due to the low surface energy is introduced, the wear resistance, scratch resistance, solvent resistance and hardness of the coating film surface are improved.

Formulas (III), (IV) and (V) are acrylates containing the hydroxyl group of the general formula (II) as described above in the remaining functional groups of the diisocyanate to which the polyol, polyester polyol and polysiloxane are bonded. By addition reaction, a urethane acrylate oligomer is manufactured by a well-known method. The hydroxy group-containing acrylate used at this time is hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate and the like. There is this.

Examples of the diisocyanate used in preparing the urethane acrylate oligomer include isopron diisocyanate (3-isocyanate, methyl 3,5,5-tremethylcyclohexyl isocyanate), 4,4'-dihexoxymethylene diisocyanate, Trimethylhexamethylene diisocyanate, 1-6-hexamethylene diisocyanate, octadecylene diisocyanate, 1-4-cyclohexylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate It is preferable to use isopron diisocyanate, 4,4'- dihexyl methylene diisocyanate, etc. among the above-mentioned diisocyanate for the ultraviolet curable coating-film composition for plastics.

Urethane acrylate, which is a reactive oligomer used in the present invention, may be used in consideration of scratch resistance and various physical properties of the coating film, which may be used in the range of 5-90 wt%, i.e. when using less than 5 wt% The scratch resistance is poor, and workability is poor when using more than 90% by weight.

The reactive monomer of the present invention may be polymerized with the oligomer to affect the physical properties of the coating film, and one or more monomers may be used. The main monomers are acrylic ester monomers prepared by esterifying an alcohol with an unsaturated carboxylic acid. As the acrylate ester monomer, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, neopentyl Glycol diacrylate, ethylene glycol dimethacrylate, detraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, tripropylene glycol diacrylate, pentaerythritol triacrylate, and the like. In consideration of phosphorus, 1,6-hexane diol diacrylate, tripropylene glycol diacrylate, trimethylol propane triacrylate, pentaerythritol tetraacrylate and the like are usefully used. The amount used may be 5-80% by weight of the whole varnish composition, but in consideration of viscosity, it is preferable to use 20-60% by weight.

The photoinitiator uses a conventional polymerization initiator which exhibits activity by ultraviolet rays, and uses compounds such as benzophenone series, benzyldimethyl ketal series, acetophenone series, anthraquinone series, thioxanthone series, and 0.5-10 weight of the whole varnish composition. % use. In particular, typical photoinitiators include hydroxy-cyclohexylphenyl ketone, 2,2-dimethoxy-2phenylacetophenone, benzophenone, and phenyl-2-hydroxy-2-propylketone.

The leveling agent uses a silicon diacrylate-based or silicone polyacrylate-based compound at 0.1-5% by weight of the whole varnish composition.

Coating work on plastic molded products is spray, dipping, roll coating, etc. The coating method can be selected depending on the material of the plastic, the formation of the molded article, the thickness of the coating film and the like.

When different viscosities are required according to these coating methods, volatile diluents may be added to adjust the 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, and the like, and these may be used by mixing one or more of them. The amount used should be such that the weight ratio of varnish and diluent is 4: 1-1: 3.

Other additives add an appropriate amount of a known compound used in the coating composition to suit the characteristics of the application.

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

58 parts by weight of a polyester polyol having a molecular weight of 448 formed by condensation of adipic acid and neopentyl glycol at 222 parts by weight of isopron diisocyanate 85 parts by weight of PTHF 650, 30 parts by weight of KF-6001 and 116 parts by weight of hydroxyethyl acrylate Reaction was carried out to prepare a urethane acrylate, 30 parts by weight of this urethane acrylate, 10 parts by weight of trimethylolpropane triacrylate, 6.5 parts by weight of 1,6-hexanediol diacrylate 2.2-dimethoxy-2-phenylacetophenone 3 Part by weight, 0.5 parts by weight of Ebecryl 360 from Mercury Cotton, 30 parts by weight of methylethylkenone, and 20 parts by weight of isopropyl alcohol were stirred at 30-40 ° C. to form a photocurable varnish.

Example 2

67 parts by weight of a polyester polyol having a molecular weight of 448, 97 parts by weight of PTHF-650, and KF- prepared by condensing adipic acid and neopentyl glycol at 222 parts by weight of isopron diisocyanate in the preparation of the urethane acrylate of Example 1. A photocurable varnish was prepared in the same composition and content as in Example 1 except that 25 parts by weight of 6001 was used.

Example 3

90 parts by weight of a polyester polyol having a molecular weight of 448 prepared by condensation of adipic acid and neopentyl glycol at 222 parts by weight of isopron diisocyanate in the preparation of the urethane acrylate of Example 1, 130 parts by weight of PTHF-650 and KF- A photocured amount varnish was prepared in the same composition and content as in Example 1 except that 12.4 parts by weight of 6001 was used.

Comparative Example 1

Except for using 134 parts by weight of a polyester polyol having a molecular weight of 448 prepared by condensing adipic acid and neopentyl glycol in 222 parts by weight of isopron diisocyanate in the preparation of the urethane acrylate of Example 1, Make a curable varnish.

Claims (3)

Polytetrahydrofuran having a molecular weight of 500 to 3000 represented by General Formula (III) A polyester polyol having a hydroxyl group of 200 to 250 represented by General Formula (IV), a molecular weight of 450 to 500, and a molecular weight represented by General Formula (V) is 50 A polysiloxane having a concentration of ˜1000 is reacted with one functional group of cyclic or aromatic diisocyanate in a composition comprising a weight ratio of 5 to 90/5 to 90/5 to 90, and then the other isocyanate functional group is terminated with the general formula (II) A method for producing a urethane acrylate oligomer having excellent scratch resistance represented by the following general formula (I), characterized by addition reaction with an acrylate containing a hydroxy group. Wherein X is an acrylate backbone of general formula (III), R ¹ is an aliphatic, cycloaliphatic or aromatic compound, and Y is a polyol, polyester polyol and polysiloxane. In the above formula, R ² is hydrogen or methyl group, R ₃ is an alkylene group having 1-12 carbon atoms. Wherein m is an integer of 6-42. R ⁶ and R ⁷ are alkyl, haloalkyl, cyanoalkyl or alkenyl and k is an integer from 1-18. Paint consisting of 5-90% by weight of reactive oligomer, urethane acrylate oligomer of general formula (I), 5-80% by weight of reactive monomer, 0.5-10% by weight of photoinitiator, 0.1-5% by weight of silicone-based leveling agent and other additives Composition. The method according to claim 1, wherein the reactive monomer is an acrylic ester monomer.