KR20070072000A - Ultraviolet and thermal curable resin compositions and coating compositions containing the same - Google Patents

Abstract

Provided are a resin composition for a paint which can be cured by heat and UV rays and improves adhesion and weather resistance, and a transparent paint for the top coat of an automobile containing the composition. The resin composition comprises: an acrylic polyol resin which comprises 5-20 parts by weight of a silanyl group-containing acrylic monomer, 5-20 parts by weight of a hydroxyl group-containing acrylic monomer, 4-20 parts by weight of a vinyl-based monomer, 10-40 parts by weight of a non-functional acrylic monomer, 1-10 parts by weight of dipentene and 1-5 parts by weight of 2-(2'-hydroxy-5'-methacryloxyethylphenyl)-2H-benzotriazole as a UV absorbing monomer; and a urethane acrylate resin which comprises 10-80 parts by weight of an isocyanate monomer, 5-80 parts by weight of a hydroxyl group-containing acrylic monomer and 1-10 parts by weight of 2-hydroxy-3,5-diol phenyl benzotriazole as a UV absorber.

Description

Ultraviolet and thermosetting resin composition and coating composition including the same {ULTRAVIOLET AND THERMAL CURABLE RESIN COMPOSITIONS AND COATING COMPOSITIONS CONTAINING THE SAME}

The present invention relates to a UV and thermal co-curable resin and a coating composition comprising the same. More specifically, the present invention is an acrylic in which a silane group and dipentene, which is a polymerization chain transfer agent, and 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole are introduced into the molecule. Polyol resins; And a urethane acrylate resin having an unsaturated double bond and having a 2-hydroxy 3,5-diolphenyl benzotriazole which is a UV absorber in a molecule thereof, and a transparent resin coating for automobile coating comprising the same. will be.

Compared with conventional thermosetting automotive coatings, conventional transparent coatings for automotive topcoats using UV and thermo-curable resins are more environmentally friendly and have simpler facilities, resulting in improved productivity, energy savings, and high gloss of cured products. Due to the uncured oligomer during UV curing, there was a problem in that yellowing or cracking occurred after coating film composition, or adhesion with a metal base was poor.

The present inventors are trying to improve the above problems, and in the synthesis of polyol, 2- (acryl acrylate-containing monomers, hydroxyl-containing acrylic monomers, vinyl-based monomers, non-functional acrylic monomers, dipentene and ultraviolet absorbers in the molecule 2 ( Acrylic polyol resin incorporating 2'hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole; And coating compositions including acrylic monomers containing hydroxyl groups in isocyanates and urethane acrylate resins having 2-hydroxy 3,5-diolphenol benzotriazole as ultraviolet absorbers improve adhesion and high weather resistance. Thus, the present invention has been completed.

Accordingly, an object of the present invention is to provide a resin composition which improves yellowing and cracks caused by unreacted oligomers and improves adhesiveness when coating UV and heat for curing at the same time, and a transparent coating for automotive coating containing the same.

5-20 weight part of silane group containing acrylic monomers, 5-20 weight part of hydroxyl-containing acrylic monomers, 4-20 weight part of vinylic monomers, 10-40 weight part of non-functional acrylic monomers, and 1-10 weight part of dipentenes And acrylic polyol resin containing 1 to 5 parts by weight of 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole as an ultraviolet absorbing monomer; And

For paints containing urethane acrylate resin containing 10 to 80 parts by weight of isocyanate monomer, 5 to 80 parts by weight of hydroxyl group-containing acrylic monomer, and 1 to 10 parts by weight of 2-hydroxy 3,5-diolphenyl benzotriazole as ultraviolet absorber. It relates to a resin composition.

The acrylic polyol resin is a structural property containing dipentene in the molecule to prevent the occurrence of yellowing and cracks, improve the adhesion, and the flexibility and elastic properties of the coating film which is an advantage of the silane group and ester bond It improves chipping property and introduces the coating material property which is more effective to weather resistance by introducing a ultraviolet absorber into a resin composition.

The urethane acrylate resin has a characteristic of providing a more effective coating film property to weather resistance by introducing a UV absorber into the resin composition by increasing the curing density by a large number of unsaturated double bonds in the molecule, thereby increasing the curing density.

Compositional components and contents of the resin composition for coatings according to the present invention are as follows.

1) acrylic polyol resin

Examples of the silane group-containing acrylic monomer that may be used to prepare the acrylic polyol resin of the present invention may be used, but is not limited thereto.

In the above formula.

n is an integer between 1 and 4, preferably an integer of 1 or 2,

R ¹ is a hydrogen atom or an alkyl, preferably a hydrogen atom or a C _{1 -6} lower alkyl,

R ² or R ³ are each alkyl or alkoxy group, preferably a C _{1 -6} lower alkyl or C _{1 -6} lower alkoxy.

Preferred silane group-containing acrylic monomers are methacryloxy-propyltrimethoxysilane, methacryloxypropyltriethoxysilane or ethacryloxypropyltrimethoxysilane.

5-20 weight part of the total amount of this resin can be used for a silane group containing acrylic monomer. When the amount of the silane group-containing acrylic monomer is less than 5 parts by weight, the coating property and the chemical resistance, which are inherent in the silane group, are inferior when the paint is applied. When the amount is more than 20 parts by weight, the viscosity is increased due to the reaction between the silane and water in the air after preparing the transparent paint. Increases storage stability.

As the hydroxyl group-containing acrylic monomer that can be used for producing the acrylic polyol resin of the present invention, there is an acrylic monomer containing a conventional hydroxyl group used in the thermosetting resin composition for coating. Examples include, but are not limited to, mono- or di-hydroxy alkyl (meth) acrylates, lactone (meth) acrylates, and hydroxy alicyclic (meth) acrylates. Preferably 2-hydroxyethyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, carduraacrylate, kadura Methacrylate, caprolactone acrylate, caprolactone methacrylate, 2,3-dihydroxypropylacryl, 2,3-dihydroxypropylmethacrylate, 4-hydroxymethylcyclohexylmethylacrylate, and 4-hydroxymethylcyclomethylmethacrylate can be used.

The hydroxyl monomer-containing acrylic monomer may be used within 5 to 20 parts by weight of the total amount of the resin. When the amount of the hydroxyl monomer-containing acrylic monomer is less than 5 parts by weight, the crosslinking density of the coating film is lowered and the coating film properties are lowered. When the amount of the acrylic monomer containing hydroxyl groups is less than 20 parts by weight, the crosslinking density is increased and the coating film properties are improved. There is a problem in that the compatibility with the compositions is lowered and the appearance of the coating film is worsened.

As the vinyl monomer that may be used to prepare the acrylic polyol resin of the present invention, a conventional vinyl monomer used as a resin composition for coating may be used. For example, a substituted or unsubstituted styrene or vinyl acetate may be used. It is not limited to. Preferably, styrene, vinyltoluene, vinyl acetate or α-methylstyrene may be used.

The vinyl monomer may be used within 4 to 20 parts by weight of the total resin. If the amount of the vinyl monomer is less than 4 parts by weight affects the gloss and the appearance is lowered, if it exceeds 20 parts by weight may be long-term weather resistance when applying the paint.

As the non-functional acrylic monomer that can be used to prepare the acrylic polyol resin of the present invention, an alkyl (meth) acrylate substituted or unsubstituted by alicycle may be used. Preferably methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, t-butyl methacrylate, normal hexyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate Acrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, normal butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, normal octyl acrylate, iso Bonylacrylates and cyclohexylacrylates include, but are not limited to.

10-40 weight part of nonfunctional acrylic monomers can be used. If the amount of the non-functional acrylic monomer is less than 10 parts by weight or more than 40 parts by weight, the coating film may be harder or more flexible than necessary, and thus may not exhibit specific physical properties, thereby reducing appearance, scratch resistance, and chipping resistance.

Dipentene represented by compound 1 is used as a polymerization chain transfer agent that can be used to prepare the acrylic polyol resin of the present invention.

Compound 1.

Dipentene can be used within 1 to 10 parts by weight of the total resin. If dipentene is used at less than 1 part by weight, the yellowing and lowering of reactivity are exhibited, and if it is more than 10 parts by weight, an additional product can be formed, which leads to a decrease in physical properties.

The ultraviolet absorbing monomer used for preparing the acrylic polyol resin of the present invention is 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole represented by the following compound 2.

The UV absorber used in the automotive coating composition can be used in the preparation of the resin. When the compound 2 according to the present invention is used as a UV absorbing monomer modified in an acrylic monomer, the UV absorbing ability is excellent to have high weather resistance properties when forming a coating film. do.

Compound 2.

The ultraviolet absorbing monomer may be used 1 to 5 parts by weight. When the ultraviolet absorbing monomer is used in an amount less than 1 part by weight, the inherent physical properties may not be exhibited, and the weather resistance of the coating film may be lowered.

As an initiator that can be used to prepare the acrylic polyol resin of the present invention, a conventional coating composition initiator may be used. Examples of preferred initiators include 2,2'-azobis (2-methylbutylonitrile) and 2,2'-azo. Bisisobutylonitrile, dibenzoylperoxide, t -butylperoxybenzoate, di- t -butylperoxide, t -butylperoxy 2 ethylhexanoate, t-butylperoxy acetate, cumyl hydroperoxide, Dicumyl peroxide, t-butylhydro peroxide and the like. The use amount of initiator is 1-15 weight part.

Solvents that can be used to prepare the acrylic polyol resin of the present invention include aromatic hydrocarbons such as toluene or xylene; Ketones such as methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, methyl isobutyl ketone or methyl alkyl ketone; Ester solvents such as methyl acetate, ethyl acetate, normal propyl acetate, isopropyl acetate, butyl acetate, methyl cellosolve acetate, cellosolve acetate or butyl cellosolve acetate, and carbitol acetate; And alcohol solvents such as normal propanol, isopropanol, normal butanol, isobutanol or t- butanol. Solvents may be used in addition to the acrylic polyol resin in 20 to 40 parts by weight.

Acrylic polyol resin according to the present invention having a weight ratio of the above components has a solid content of 60-80%, a weight average molecular weight of 3000-50000, a hydroxyl group of 50 to 150, the glass transition temperature (Tg) is It is preferable that it is -10-60 degreeC. If the weight average molecular weight is less than 3000, all physical properties are deteriorated in terms of structural stability. If the weight average molecular weight is 50000 or more, the viscosity may be increased to affect workability and shelf life. In addition, if the glass transition temperature is -10 ℃ or less, the flexibility in forming the coating film may be reduced solvent resistance and chemical resistance, and if it is 60 ℃ or more, the chipping resistance and scratch resistance is reduced by excessive curing.

2) urethane acrylate resin

Hereinafter, the urethane acrylate resin component will be described in detail.

Isocyanate monomers that can be used to prepare the urethane acrylate resins of the present invention include alkylene isocyanates, hydrogenated alkylene isocyanates, aryl isocyanates and alicyclic isocyanates. Preferred are hexamethylene diisocyanate trimer, isophorone diisocyanate, trimethylhexamethyl diisocyanate, cyclodiisocyanate, trimethyl xylene diisocyanate, hydrogenated methylene diisocyanate, hydrogenated xylene diisocyanate, and xylene diisocyanate and the like It can be used within 10 to 80 parts by weight of the total amount.

10 to 80 parts by weight of the isocyanate monomer may be used. If the amount of the isocyanate monomer is less than 10 parts by weight, the physical properties are lowered when the coating is applied, and if it exceeds 80 parts by weight, the viscosity is increased and workability is lowered.

Examples of hydroxyl group-containing acrylic monomers that can be used to prepare the urethane acrylate resin of the present invention include hydroxy-alkyl- (meth) acrylate, hydroxy-alicyclo- (meth) acrylate and lactone- (meth) acrylate. Can be used. Preferably 2-hydroxyethyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, carduraacrylate, cardurameta Acrylate, caprolactone acrylate, caprolactone methacrylate, 2,3-dihydroxypropyl acrylate, and the like.

5 to 80 parts by weight of the total amount of the resin may be used as the hydroxyl group-containing acrylic monomer. If the amount of the hydroxyl group-containing acrylic monomer is less than 5 parts by weight, the physical properties of the coating is inferior, and if it exceeds 80 parts by weight, the viscosity increases and the synthetic stability is lowered.

1 to 10 parts by weight of 2-hydroxy 3,5-diolphenyl benzotriazole is used as the ultraviolet absorber used to prepare the urethane acrylate resin of the present invention.

If the amount of the ultraviolet absorbent is less than 1 part by weight, rapid curing may not be possible during UV absorption and UV curing when the paint is applied.

In this UV curable urethane acrylate resin composition for paints, the resin has a solid content of 80 to 100%, a number average molecular weight of 1000 to 20000, a glass transition temperature (Tg) of -60 to 60 ° C, and a reaction temperature of 50. Preference is given to those prepared at -100 ° C. However, the UV curable urethane acrylate resin having the above composition is designed so that the equivalent ratio of hydroxyl group / isocyanate group is 1 or less since crosslinking reaction occurs with acrylic polyol in the heat curing step after coating.

In addition to the composition components, a tin catalyst may be used in addition to preparing a urethane acrylate resin for promoting the reaction. Tin catalysts usable in the present invention include, but are not limited to, dibutyl tin dilaurate, dibutyl tin dimaleate, dibutyl tin diacetate, dibutyl tin dilauryl mercaptide, dimethyl tin dichlorolide, and the like. Tin catalyst may be used 0.01 to 5.0 parts by weight of the total amount of monomers. When the amount of the tin catalyst used is less than 0.01 part by weight, curing is inferior and physical properties are deteriorated.

In manufacturing the ultraviolet curable resin composition for coatings of this invention, a solvent can be used as needed. In this case, the solvent may be selected from within the solvent category that can be used to prepare the acrylic polyol resin, 20 to 40 parts by weight can be used. If the amount of the solvent used is less than 20 parts by weight, the viscosity increases during synthesis and the workability is lowered. When the amount of the solvent is used exceeds 40 parts by weight, it is difficult to control the solvent content and the solvent balance during the manufacture of the paint, thereby reducing the coating property and rheology of the coating film. do.

In the present invention, it is preferable that the equivalent ratio of the hydroxyl group of the acrylic polyol resin and the isocyanate group of the urethane acrylate resin in the paint composition is 1: 0.5 to 0.5: 1. If the equivalent ratio of isocyanate groups is less than 0.5, the degree of curing of the paint is reduced, and if it exceeds 1, the isocyanate remains in the coating film. Can be.

In another aspect, the present invention provides a transparent coating for automotive tops comprising the resin composition for coating. The automotive coating transparent paint is 20 to 50 parts by weight of the acrylic resin composition; 40 to 60 parts by weight of urethane acrylate; 0.5 to 2.0 parts by weight of a smoothing agent; 0.5-3.0 parts by weight of photoinitiator; 0.1 to 0.5 parts by weight of catalyst; It can contain 1-10 weight part of solvents.

The leveling agent that can be used in the present invention may be used a silicon-based, but is not limited thereto. Photoinitiators that can be used in the present invention may be benzoin ether, benzyl ketal, dialkoxy acetophenone, or hydroxyalkyl phenone series may be used, preferably benzyl dimethyl ketal, diethoxy acetophenone, 2-hydroxy-2-methyl -1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, acylphosphine oxide, aminoalkylphenone, and the like may be used, but are not limited thereto. Catalysts that can be used in the present invention include acids such as dodecylbenzoinsulfonic acid, paratoluenesulfonic acid, or alkyl acids; dibutyltindilaurate, dibutyltinmaleate, stenausoctoate, zirconium octoate, or Tin catalysts such as dibutyl tin diacetate, and the like, but are not limited thereto. The solvent that can be used for the top coat of the present invention is the same as the solvent that can be used to prepare the acrylic polyol resin of the present invention mentioned above.

Hereinafter, examples for describing the present invention are presented, but the present invention is not limited thereto.

Synthesis Example  1 (acrylic Polyol  Preparation of Resin, A1)

In a four-necked flask equipped with a thermometer and a cooler, 300 g and 200 g of Solvesso # 100 and butanol were added under a nitrogen atmosphere, and the temperature was raised to 125 ° C. In the solution, styrene 170g, butyl methacrylate 340g, butylacrylate 220g, hydroxyethyl acrylate 300g, methacryloxypropyltrimethoxysilane 100g, dipentene 30g, and hydroxymethacryloxyethylphenylbenzo 30 g of triazole; A mixture consisting of 55 g of 2,2'-azobis (2-methylbutylonitrile) as initiator was added over 3 hours. After the mixture was kept at 135 ° C. for 2 hours, 1.5 g of 2,2′-azobis (2-methylbutylonitrile) as an initiator was dissolved in 7.5 parts by weight of Solvesso # 100, and the dissolved mixed solution was added for 10 minutes, After a 2-hour holding reaction, the mixture was cooled to obtain a silane group-containing acrylic polyol resin.

The obtained acrylic polyol resin solution had a weight average molecular weight of 6,300, a glass transition temperature of 2 ° C, a hydroxyl group of 120, an acid value of less than 1 mg KOH / g, a solid content of 70.5%, and a viscosity (Gardner viscosity) Y, Gardner It was transparent resin whose color is one or less.

Synthesis Example  2 (acrylic Polyol  Resin, A2)

The preparation was carried out in the same manner as in Synthesis example 1, 165 g of styrene, 250 g of butyl methacrylate, 280 g of butyl acrylate, 300 g of hydroxypropyl acrylate, 145 g of methacryloxypropyl trimethoxysilane, 30 g of dipentene, The acrylic resin solution obtained by dropwise addition of a mixture consisting of 30 g of hydroxymethacryloxyethylphenylbenzotriazole and 50 g of 2,2'-azobis (2-methylbutylonitrile) as an initiator for 3 hours was a weight average molecular weight of 8400. The glass transition temperature was 20 ° C., the hydroxyl group was 107, the acid value was less than 1 mg KOH / g, the solid content was 70.3%, the viscosity (Gardner viscosity) W, and the Gardner color was 1 or less.

Synthesis Example  3 (acrylic Polyol  Resin, A3)

The preparation was carried out in the same manner as in Synthesis example 1, 144 g of styrene, 366 g of butyl methacrylate, 150 g of ethylhexyl acrylate, 150 g of methacryloxypropyltrimethoxysilane, 330 g of hydroxybutyl acrylate, and 30 g of dipentene A mixture consisting of 30 g of hydroxymethacryloxyethylphenylbenzotriazole and 25 g of 2,2'-azobis (2-methylbutylonitrile) as an initiator was added dropwise for 3 hours. The acrylic resin solution thus obtained had a weight average molecular weight of 14000, a glass transition temperature of 31 ° C, a hydroxyl group of 101, an acid value of less than 1 mg KOH / g, a solid content of 70.1%, and a viscosity (Gardner viscosity) Y +, Gardner color. It was transparent resin whose is 1 or less.

Comparative Synthesis Example  4 (acrylic Polyol  Resin, A4)

The preparation was carried out in the same manner as in Synthesis example 1, 240 g of styrene as a monomer, 493 g of butyl methacrylate, 172 g of ethylhexyl acrylate, 295 g of hydroxybutyl acrylate and 2,2'-azobis (2-methyl as an initiator A mixture consisting of 25 g of butylonitrile) was added dropwise over 3 hours. The acrylic resin solution thus obtained had a weight average molecular weight of 12000, a glass transition temperature of 28 ° C, a hydroxyl group of 101, an acid value of less than 1 mg KOH / g, a solid content of 70.1%, a viscosity (Gardner viscosity) of WY, and a Gardner color. It was transparent resin which is one or less.

Synthesis Example  5 (urethane Acrylate  Resin, B1)

587.0 g of caprolactone-modified hydroxyl acrylate (Tone-M-100), 45.0 g of 2-hydroxy-3,5-diolphenyl benzotriazole (UVA103) and 10.0 g of dibutyltin dilaurate were added to the reactor and stirred. It heated up to 60 degreeC, and 508.0 g / 127.0 g of hexamethylene diisocyanate trimer / isophorone diisocyanate trimer was added dropwise careful to exotherm for 1 hour. It was kept for 4 hours and then cooled to room temperature. Solid content of resin at this time was 99.0%, the number average molecular weight was 5700, and NCO% was the urethane acrylate resin which is 16.

Synthesis Example  6 (urethane Acrylate  Resin, B2)

The preparation method was carried out in the same manner as in Synthesis example 5. 260.0 g of hydroxyethyl acrylate, 40.0 g of 2-hydroxy-3,5-diolphenylbenzotriazole (UVA103) and 10.0 g of dibutyl tin dilaurate were added to a reactor, and the temperature was raised to 60 ° C while stirring, and hexamethylene di 750.0 g of isocyanate trimers were added dropwise to the exotherm for 1 hour. It was kept for 4 hours and then cooled to room temperature. In this case, the solid content of the resin was 99.0%, and the number average molecular weight was 1800 and the NCO% was a urethane acrylate resin of 14.

Comparative Synthesis Example  7 (urethane Acrylate  Resin, B3)

The preparation method was carried out in the same manner as in Synthesis example 5. 130.0 g of hydroxyethyl acrylate, 293.5 g of caprolactone-modified hydroxyl acrylate (Tone-M-100), and 10.0 g of dibutyl tin dilaurate were added to a reactor, and the temperature was raised to 60 ° C while stirring, and the hexamethylene diisocyanate trimer 750.0 g was added dropwise with caution to fever for 1 hour. It was kept for 4 hours and then cooled to room temperature. At this time, solid content of resin was 99.0%, the number average molecular weight was 1500, and NCO% was the urethane acrylate resin which is 17.

Example : Preparation of Coating Composition

And a photoinitiator for ultraviolet curing, by combining the hydroxyl group of the aforementioned acrylic polyol resins (A1, A2, A3 and A4) and the isocyanate group of the urethane acrylate resins (B1, B2 and B3) in a 1: 0.5-0.5: 1 equivalent ratio. In consideration of the reactivity of the intramolecular silane group, a small amount of an acid catalyst was added, and a coating composition was prepared using the silicone-based smoothing agent in the composition shown in Table 1.

The coating composition obtained as described above is applied to a UV and thermal co-curable automotive transparent paint, after applying a conventional base coat (metallic or solid color) to the base material is maintained at 80 ℃ 4 minutes and left at room temperature for 10 minutes and then transparent After coating the coating, it passed through an ultraviolet curing lamp (1500mL / cm ² ). After another 10 minutes at room temperature it was cured at 140 ℃ 30 minutes.

As the base coat paint, the physical properties of the coating film were measured using a paint made of an acrylic melamine resin system, a polyester melamine metal pigment, and a colorant, which are usually applied to automobile paints.

Physical properties measurement method is as follows.

(1) Appearance: The horizontal coating is measured by wave scan DOI.

(2) Acid resistance: It judges the damage of coating film after hold | maintaining 30 minutes at 70 degreeC temperature.

(3) Chipping resistance: chipping test after 2 hours at -40 ℃

(4) Scratch resistance: maintains 20 ° gloss after 20 repetitions with ANTEK's shower facility

(5) Crack resistance: 30 cycles test with top coat and transparent coat up to 4 times each (1 cycle: -40 ℃ * 2 hours + 110 ℃ * 2 hours + -40 ℃ * 2 hours + 110 ℃ * 2 hours + 40 ℃ hot water * 14 hours)

(6) Yellowing: Color check after over-baking (ΔE)

(7) Repaintability: Evaluation after repainting after overbaking

(8) Weather resistance: Q-PANEL's QUV device compares the coating state after 2000 hours and 4000 hours

1) The smoothing agent: polyether modified dimethylpolysiloxane copolymer

2) Photoinitiator Igacure184: 1-Hydroxy-cyclohexyl-phenyl-ketone

3) Photoinitiator Igacure819: bisacyl phosphine: phosphine oxide, phenyl bis (2,4,6-trimethyl benzyl) [Bis Acyl phosphine: phosphine oxide, phenyl bis (2,4,6-trimethyl benzyl)]

4) Acid catalyst: dodecyl benzene sulfonic acid

1) Appearance: The average value is CF (combination factors). The larger the value, the better the appearance.

2) Acid Resistance: This is a comparative value of the degree of damage.

3) Chipping resistance: After the test, the damaged coating film is compared and judged. The larger the value, the better the condition.

4) Scratch resistance: The higher the value, the higher the retention rate, which measured initial gloss and gloss after test.

5) Crack resistance: Relative comparison after test.

6) Yellowing: The color is checked after over-baking. ΔE means the difference between the initial color and the color after baking.

7) Recoating Adhesion: After coating twice, the degree of detachment of coating after test was compared.

8) Weatherability: A method of judging the state of the coating film by artificially applying heat and moisture periodically to examine the coating film after each time. Good here indicates no cracks or damage.

As described in detail above, the coating resin composition according to the present invention improves the occurrence of yellowing and cracks due to unreacted oligomers during UV and heat co-curing, improves adhesion and weather resistance, and has other application properties through dense crosslinking density. It is useful as a clear coating for automotive coatings.

Claims (6)

5 to 20 parts by weight of the silane group-containing acrylic monomer, 5 to 20 parts by weight of the hydroxyl group-containing acrylic monomer, 4 to 20 parts by weight of the vinyl monomer, 10 to 40 parts by weight of the non-functional acrylic monomer, 1 to 10 parts by weight of dipentene, and ultraviolet absorption Acrylic polyol resin containing 1 to 5 parts by weight of 2- (2'-hydroxy-5'-methacryloxyethylphenyl) -2H-benzotriazole as a monomer; And For paints containing urethane acrylate resin containing 10 to 80 parts by weight of isocyanate monomer, 5 to 80 parts by weight of hydroxyl group-containing acrylic monomer, and 1 to 10 parts by weight of 2-hydroxy 3,5-diolphenyl benzotriazole as ultraviolet absorber. Resin composition. The resin composition for coating of Claim 1 whose silane group containing acrylic monomer is a compound of following General formula (1). [Formula 1]

Where n is an integer between 1 and 4, R ¹ is a hydrogen atom or an alkyl, R ² Or R ³ is alkyl or alkoxy, respectively. According to claim 1, wherein the acrylic polyol resin has a solid content of 60-80%, a weight average molecular weight of 3000-50000, a hydroxyl group is 50-150, the glass transition temperature (Tg) is -10 ~ 60 ℃ Resin composition for coatings characterized by the above-mentioned. The resin composition for coating according to claim 1, wherein the urethane acrylate resin has a solid content of 80 to 100%, a number average molecular weight of 1000 to 20000, and a glass transition temperature (Tg) of -60 to 60 ° C. . The coating composition according to claim 1, wherein an equivalent ratio of the hydroxyl group of the acrylic polyol resin of claim 1 to the isocyanate group of the urethane acrylate resin is 1: 0.5 to 0.5: 1. The transparent coating material for automotive tops containing the resin composition for coatings of any one of Claims 1-5.