KR20080061581A - Photo-curable paint composition and coating method using the same - Google Patents

Abstract

A photocurable coating composition is provided to realize excellent scratch resistance, adhesion and weather resistance, thereby improving the quality of a protective coating layer, particularly for a helmet. A photocurable coating composition comprises: 35-55 parts by weight of an aliphatic urethane acrylate oligomer; about 3-10 parts by weight of a multi-functional urethane acrylate oligomer; about 25-45 parts by weight of a reactive acrylic monomer; about 2-7 parts by weight of a photoinitiator; and about 2.5-8 parts by weight of additives including an adhesion enhancer. The aliphatic urethane acrylate oligomer has two functional groups. The multi-functional urethane acrylate oligomer has 6-15 functional groups.

Description

Photo-curable coating composition and coating method using the same {PHOTO-CURABLE PAINT COMPOSITION AND COATING METHOD USING THE SAME}

The present invention relates to a photocurable coating composition and a coating method using the same, and more particularly, to a photocurable coating composition having excellent adhesion to scratches, scratch resistance, weather resistance and the like and a coating method using the same.

In general, the material of the helmet is a hard molded article formed of unsaturated polyester, and in order to decorate it, a method of transferring a print transfer paper on a helmet holder is used. However, the print transfer paper is weak in scratchability and easily scratched or damaged, and thus has low durability. As a method to compensate for this problem, a protective coating is required, and as a protective coating method for a helmet, a two-component type in which an acrylic resin and a urethane resin are mixed or a one-component type made of a urethane resin is used.

However, in order to satisfy desirable hardness, scratch resistance, and the like, a new type of paint selection was required, and as an alternative, an ultraviolet curable paint has been considered. Already in foreign countries, products coated with UV curable paints have been released, and domestic companies are also actively examining them. When applying the UV curable paints as coating materials, they may have advantages of excellent workability due to fast curing time.

Generally, the ultraviolet curable paint includes oligomers, monomers, photoinitiators and additives. The photoinitiator serves to generate radicals by ultraviolet rays, and the radicals generated by the photoinitiator attack the double bonds of the oligomer and the monomer to form a three-dimensional network structure, thereby forming a rigid coating film.

In general, there are various kinds of oligomers that can be used in the UV-curable paint, oligomers that can be applied to UV-curable paint for helmet coating is known yellow polyester type acrylate, urethane acrylate and the like.

The polyester acrylate oligomer has the advantages of low cost, a variety of compounds can be obtained by the combination of polybasic acid and polyhydric alcohol, and is convenient to use in a low viscosity type. On the other hand, there is a disadvantage that the chemical resistance due to the ester bonding is bad.

Urethane acrylate oligomers have the advantages of high reactivity and excellent hardness, adhesiveness, chemical resistance and the like of the cured coating film. On the other hand, the paint has a high viscosity and has a weak weather resistance.

Urethane acrylate oligomers can also be divided into aromatic urethane acrylates and aliphatic urethane acrylates. Among these, the aromatic urethane acrylate is weak in weatherability and easy to yellow, but has an advantage of low cost, and the aliphatic urethane acrylate has good characteristics in processability, reactivity, weather resistance and chemical resistance, but has a disadvantage in being expensive.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and to provide a photocurable coating composition excellent in adhesion and scratch resistance and a coating method using the same.

Photocurable coating composition according to an aspect of the present invention is 35 to 55 parts by weight of aliphatic urethane acrylate oligomer, about 3 to about 10 parts by weight of polyfunctional urethane acrylate oligomer, about 25 to about 45 parts by weight of reactive acrylic monomer, photoinitiator about 2 to about 7 parts by weight and about 2.5 to about 8 parts by weight of an additive including an adhesion promoter.

According to the coating method according to another aspect of the present invention, by attaching a printing paper to the surface of the object to transfer a predetermined pattern. 35 to 55 parts by weight of aliphatic urethane acrylate oligomer, about 3 to about 10 parts by weight of polyfunctional urethane acrylate oligomer, about 25 to about 45 parts by weight of reactive acrylic monomer, and about 2 to about photoinitiator on the surface of the object on which the pattern of the composition is formed. A coating of the photocurable coating composition comprising about 7 parts by weight to about 8 parts by weight of an additive including an adhesion promoter. Ultraviolet rays are irradiated to the coated photocurable coating composition to form a cured coating film.

The photocurable coating composition may be coated using a spray method.

As described above, a coating film excellent in scratch resistance, adhesion, and weather resistance can be obtained, thus improving the quality of the protective coating film.

Hereinafter, the photocurable coating composition and the coating method of the present invention will be described in detail.

Photocuring composition

Photocurable coating composition according to an embodiment of the present invention is about 35 to about 55 parts by weight of aliphatic urethane acrylate oligomer, about 3 to about 10 parts by weight of polyfunctional urethane acrylate oligomer, about 25 to about 45 parts by weight of reactive acrylic monomer , About 2 to about 7 parts by weight of the photoinitiator and about 2.5 to about 8 parts by weight of the additive.

The aliphatic urethane acrylate oligomer is yellowing type and has good flexibility to increase the adhesion of the photocurable coating composition. Specifically, commercially available CN965, CN966H90, CN966J75, CN980, CN981, CN982, CN985 (above product name, SARTOMER, USA) and the like can be cited, and these may be used alone or in combination, respectively.

When the content of the urethane acrylate oligomer is less than 35 parts by weight, there is a disadvantage that the flexibility, such as after UV curing coating is lowered, and when the content of the urethane acrylate oligomer exceeds 55 parts by weight, the coating film is excessively flexible and scratch resistance Not only is this lowered, there is a disadvantage in that the viscosity of the paint is increased, resulting in problems in workability.

The polyfunctional urethane acrylate oligomer may improve scratch resistance of the coating film, and in view of the light curing speed and water resistance, it is preferable to have 6 to 15 functional groups. Specifically, commercially available U-6LHA (6-functional group), U-520 (10-functional group), U-15HA (15-functional group) (above product name, Shin-Nakamura Chemical, Japan), etc. are exemplified. Each may be used alone or in combination.

When the content of the polyfunctional urethane acrylate monomer is less than 3 parts by weight, the scratch resistance of the coating film may be lowered. When the content of the polyfunctional urethane acrylate monomer exceeds 10 parts by weight, the hardness of the coating film is excessively increased. Cracking of the surface of the coating film may occur, the viscosity of the coating film may rise, and is economically disadvantageous.

The reactive acrylic monomer may be a monofunctional or polyfunctional acrylic monomer, specifically, isobonyl acrylate (isobonyl acrylate: IBOA), isobonyl methacrylate (isobonyl methacrylate: IBOMA), tetrahydrofuryl acrylate (tetrahydrofuryl acrylate) : THFA), Acryloyl morpholine (ACMO), 2-phenoxyethyl acrylate (2-phenoxyethyl acrylate), tripropyleneglycol diacrylate (TPGDA), 1,6-hexanediol diol Acrylate (1,6-hexane diol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerytritol hexaacrylate (dipentaerytritol hexaacrylate) : DPHA) and the like. These may be used alone or mixed, respectively, it is preferable to mix the appropriate monomer in consideration of the hardness, curing time and price of the coating film.

The photoinitiator is activated by ultraviolet rays, and a conventional polymerization initiator may be used. Specifically, a benzophenone compound, a benzoin compound, a benzoin ether compound, a benzyl ketal compound, an acetophenone compound, an anthraquinone compound, a thioxoxanthone compound, or the like may be used, and each of these may be used alone or in combination. Can be used. More specifically, commercially available CIBA Chemical (Switzerland) Irgacure 184, 651, 819 (above product name, CIBA Chemical, Switzerland), Micure HP-8, Benzophenone (more product name, Miwon Corporation, Korea) and the like can be used. have.

When the content of the photoinitiator is less than 2 parts by weight, there is a high possibility that the curing does not proceed sufficiently, and when the content of the photoinitiator exceeds 8 parts by weight, the price is increased and the storage stability is lowered.

The additive may include an antifoaming agent, a slipping agent and an adhesion promoter. The antifoaming agent, the slipping agent and the adhesion enhancer may be used conventionally, and the adhesion enhancer may preferably include a phosphate-acrylic adhesion promoter and a succinate ester adhesion promoter. The adhesion promoter serves to increase adhesion to the body of the photocurable coating composition, preferably, the content of the adhesion promoter may be about 2 to about 7 parts by weight.

The photocurable coating composition may further include a solvent in order to obtain a suitable viscosity. The amount of the solvent may be about 30 to 60 parts by weight, and considering that the coating of the photocurable coating composition mainly consists of a spray method, the solvent may be exemplified by alcohol, ester cellulose or toluene, respectively. It may be used alone or in combination.

The photocurable coating composition according to the embodiment of the present invention is excellent in adhesion with a transfer paper, scratch resistance and weather resistance. Thus, the quality of the protective coating can be improved.

Coating method

According to the coating method according to an embodiment of the present invention, the printing transfer paper is attached to the surface of the object to transfer a predetermined pattern. As the transfer method, a thermal transfer method or a water transfer method may be used. The photocurable coating composition is coated on the surface of the object to which the pattern is transferred and cured to form a coating film. Curing of the photocurable coating composition is achieved by irradiation with ultraviolet rays. For example, the object may be a protective helmet manufactured by molding or the like.

The photocurable composition may include about 35 to about 55 parts by weight of an aliphatic urethane acrylate oligomer, about 3 to about 10 parts by weight of a polyfunctional urethane acrylate oligomer, about 25 to about 45 parts by weight of a reactive acrylic monomer, and about 2 to about 7 parts by weight of a photoinitiator. Parts, about 2.5 to about 8 parts by weight of the additive and about 30 to 60 parts by weight of the solvent. Since the photocurable coating composition is substantially the same as the photocurable coating composition according to an embodiment of the present invention described above, a detailed description thereof will be omitted.

The coating method according to an embodiment of the present invention can form a coating film excellent in adhesion with a transfer paper, scratch resistance and weather resistance, and can be used for not only a protective helmet but also other members manufactured by a similar method. .

Hereinafter, a photocurable coating composition and a coating method using the same will be described through specific examples and comparative examples.

Example 1

About 50 parts by weight of aliphatic urethane acrylate oligomer, about 8 parts by weight of U-15HA as polyfunctional urethane acrylate oligomer, about 15 parts by weight of 1,6-hexanediol diarylate as reactive acrylic monomer, about 10 parts by weight of isobornyl acrylate To about 7 parts by weight of acryloyl morpholine, about 5 parts by weight of Irgacure 184 as a photoinitiator, about 0.2 parts by weight of a slip agent, about 0.3 parts by weight of an antifoaming agent, and about 4.5 parts by weight of an adhesion promoter, a photocurable coating composition was prepared.

Example 2

About 40 parts by weight of aliphatic urethane acrylate oligomer, about 6 parts by weight of U-15HA as a polyfunctional urethane acrylate oligomer, about 9 parts by weight of tripropylene glycol diacrylate as a reactive acrylic monomer, about 15 parts by weight of trimethylolpropane triacrylate , About 15 parts by weight of acryloyl morpholine, about 7 parts by weight of Irgacure 184 as a photoinitiator, about 0.2 parts by weight of a slip agent, about 0.3 parts by weight of an antifoaming agent, and about 6.5 parts by weight of an adhesion promoter, to prepare a photocurable coating composition.

Example 3

About 44 parts by weight of aliphatic urethane acrylate oligomer, about 8 parts by weight of U-15HA as a polyfunctional urethane acrylate oligomer, about 10 parts by weight of dipentaerythritol hexaacrylate as a reactive acrylic monomer, about 15 parts by weight of trimethylolpropane triacrylate To about 15 parts by weight of acryloyl morpholine, about 5 parts by weight of Irgacure 184 as a photoinitiator, about 0.2 parts by weight of a slip agent, about 0.3 parts by weight of an antifoaming agent, and about 2.5 parts by weight of an adhesion promoter, a photocurable coating composition was prepared.

Comparative Example 1

About 30 parts by weight of aliphatic urethane acrylate oligomer, about 15 parts by weight of U-15HA as a polyfunctional urethane acrylate oligomer, about 20 parts by weight of trimethylolpropane triacrylate as a reactive acrylic monomer, about 25 parts by weight of acryl morpholine, photoinitiator As a photocurable coating composition, about 5 parts by weight of Irgacure 184, about 0.2 part by weight of slip agent, about 0.3 part by weight of antifoaming agent, and about 4.5 parts by weight of adhesion promoter were prepared. The composition of the components used is shown in Table 1 below.

Comparative Example 2

About 43 parts by weight of aliphatic urethane acrylate oligomer, about 10 parts by weight of U-6LHA as polyfunctional urethane acrylate oligomer, about 10 parts by weight of trimethylolpropane triacrylate as reactive acrylic monomer, about 15 parts by weight of isobornyl acrylate About 15 parts by weight of ripropylene glycol diacrylate, about 5 parts by weight of Irgacure 184 as a photoinitiator, about 0.2 parts by weight of slip agent, about 0.3 parts by weight of antifoaming agent, and about 1.5 parts by weight of adhesion promoter were prepared to prepare a photocurable coating composition. The composition of the components used is shown in Table 1 below.

Comparative Example 3

About 60 parts by weight of aliphatic urethane acrylate oligomer, about 5 parts by weight of U-15HA as urethane acrylate oligomer, about 10 parts by weight of trimethylolpropane triacrylate as reactive acrylic monomer, about 5 parts by weight of tripropylene glycol diacrylate, acryl About 10 parts by weight of royl morpholine, about 7 parts by weight of Irgacure 184 as a photoinitiator, about 0.2 parts by weight of slip agent, about 0.3 parts by weight of antifoaming agent, and about 2.5 parts by weight of adhesion promoter were prepared to prepare a photocurable coating composition. The composition of the components used is shown in Table 1 below.

Table 1

(Unit: parts by weight)

Raw material Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Aliphatic urethane acrylate 50 40 44 30 43 60 U-6LHA - - - - 10 - U-15HA 8 6 8 15 - 5 DPHA - - 10 - - - TMPTA - 15 15 20 10 10 HDDA 15 - - - 15 - TPGDA - 10 - - - 5 IBOA 10 - - - 15 - ACMO 7 15 15 25 - 10 Photoinitiator 5 7 5 5 5 7 Slip 0.2 0.2 0.2 0.2 0.2 0.2 Antifoam 0.3 0.3 0.3 0.3 0.3 0.3 Adhesion promoter 4.5 6.5 2.5 4.5 1.5 2.5 Sum 100 100 100 100 100 100

Experimental Example-Evaluation of Physical Properties of Photocurable Coating Composition

50 parts by weight of a solvent containing a mixture of alcohol, ester cellulose and toluene were mixed and stirred in each of the photocurable coating compositions prepared according to Examples 1 to 3 and Comparative Examples 1 to 3.

The photocurable coating compositions of Examples 1 to 3 and Comparative Examples 1 to 3 containing the solvent were applied to a transfer paper to a thickness of about 20 to about 30 μm using a bar coater, and then an ultraviolet curing device 1500 -2000mJ / cm ² ) to obtain a cured coating specimen.

In order to evaluate the UV curability, each cured coating film specimen was examined for the tack-freeness of the cured coating film using POWER PUCK (product name, EIT Inc., USA), which is a curable measurement photometer.

In order to evaluate the adhesion to the transfer paper, the adhesion of each cured coating film specimen was measured according to JIS D0202.

In order to evaluate the scratch resistance, each cured coating film specimen was pressed with a coating film with the same force with a coin, and the scratch was observed visually.

In order to evaluate the pencil hardness, the pencil hardness of each cured coating specimen was measured according to NCAA-II-12.

In order to evaluate the weather resistance, each cured coating specimen was placed in a QUV tester and exposed for about 100 hours, and then the change of discoloration, discoloration and gloss was measured. In the Weather-O-Meter (WOM) test, the change of color and gloss was measured by changing temperature and humidity while irradiating ultraviolet rays.

The results of the above experimental measurement are shown in Table 2 below according to the four-step evaluation method (◎: excellent, O: good, △: normal, ×: poor) (except pencil hardness).

TABLE 2

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 UV curable O ◎ O O O △ Adhesion ◎ ◎ ◎ × × ◎ Scratch resistance O O ◎ O △ × Pencil hardness 2H 2H 2H 4H 2H F Weather resistance ◎ O O × O O ◎: Excellent, O: Good, △: Normal, ×: Poor

Referring to Table 2, in the case of the coating film prepared in Comparative Example 1 containing about 30 parts by weight of an aliphatic urethane acrylate oligomer, it can be seen that the adhesion and weather resistance are reduced, and the additive is included in Comparative Example 2 containing about 2 parts by weight. In the case of the manufactured coating film, it turns out that adhesiveness falls. In addition, in the case of the coating film prepared in Comparative Example 3 containing about 60 parts by weight of an aliphatic urethane acrylate oligomer, it can be seen that scratch resistance and pencil hardness are reduced.

According to this invention, the coating film excellent in scratch resistance, adhesiveness, weather resistance, etc. can be obtained using a photocurable coating composition, Therefore, the quality of a protective coating film can be improved.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (11)

35 to 55 parts by weight of an aliphatic urethane acrylate oligomer; About 3 to about 10 parts by weight of a multifunctional urethane acrylate oligomer; About 25 to about 45 parts by weight of reactive acrylic monomer; About 2 to about 7 parts by weight of photoinitiator; And A photocurable coating composition comprising about 2.5 to about 8 parts by weight of an additive including an adhesion promoter. The photocurable coating composition according to claim 1, wherein the aliphatic urethane acrylate oligomer has a bifunctional group. The photocurable coating composition according to claim 1, wherein the polyfunctional urethane acrylate oligomer has 6 to 15 functional groups. The method of claim 1, wherein the reactive acrylic monomer is isobonyl acrylate (isobonyl acrylate), isobonyl methacrylate (isobonyl methacrylate), tetrahydrofuryl acrylate (tetrahydrofuryl acrylate), acryloyl morpholine (Acryloyl morpholine), 2-phenoxyethyl acrylate, tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate (Trimethylolpropane triacrylate), pentaerythritol triacrylate (pentaerythritol triacrylate) and dipentaerythritol hexaacrylate (dipentaerytritol hexaacrylate) comprising at least one or more selected from the group consisting of. The photocurable coating composition of claim 1, wherein the additive further comprises at least one of an antifoaming agent and a slipping agent. The photocurable coating composition of claim 1, wherein the adhesion promoter comprises at least one of a phosphate-acrylic adhesion promoter and a succinate ester adhesion promoter. The photocurable coating composition of claim 1, wherein the adhesion promoter is 2 to 7 parts by weight. The photocurable coating composition according to claim 1, further comprising 30 to 60 parts by weight of a solvent including at least one selected from the group consisting of alcohol, ester cellulose and toluene. Attaching a print transfer paper to the surface of the object to transfer a predetermined pattern; 35 to 55 parts by weight of aliphatic urethane acrylate oligomer, about 3 to about 10 parts by weight of polyfunctional urethane acrylate oligomer, about 25 to about 45 parts by weight of reactive acrylic monomer, about 2 to about photoinitiator on the surface of the object to which the pattern is transferred Coating a photocurable coating composition comprising about 2.5 to about 8 parts by weight of an additive comprising 7 parts by weight and an adhesion promoter; And And coating the photocurable coating composition with ultraviolet rays to form a cured coating film. 10. The method of claim 9, wherein the object is a protective helmet. The coating method according to claim 9, wherein the photocurable coating composition is coated by a spray method.