KR101138789B1 - Glossy top coat clear paint composition for PCM print on home appliance - Google Patents

Abstract

The present invention relates to a gloss top clear coating composition for PCM home appliance printing having excellent processability, mechanical properties, chemical resistance, and good clarity, and more particularly, has an aromatic, aliphatic, or cyclo aliphatic structure. Glossy top coat for PC home appliance printing that requires high gloss and high sensation by forming a clear top coat composition by mixing additives such as curing agent, curing accelerator, surface conditioner and solvent with polyester resin synthesized by condensation reaction of alcohol and polyacid. It provides a clear coating composition.

Description

Gloss top coat clear paint composition for PCM print on home appliance}

The present invention relates to a gloss top clear coating composition for PCM home appliance printing having excellent processability, mechanical properties, chemical resistance, and good clarity, and more particularly, has an aromatic, aliphatic, or cyclo aliphatic structure. Glossy top coat for PC home appliance printing that requires high gloss and high sensation by forming a clear top coat composition by mixing additives such as curing agent, curing accelerator, surface conditioner and solvent with polyester resin synthesized by condensation reaction of alcohol and polyacid. It provides a clear coating composition.

The demand for high glossiness / high gloss at the high gloss level is increasing in home appliance print products coated with PCM gravure offset method. As home appliances increase not only from simple white home appliances, but also to increase the role of interiors, they have various patterns / colorful colors / beautiful appearances, and have delicate processing, excellent hardness and chemical resistance, which are basic physical properties that PCM should have. The development of clear paint applied to the printing products for dragon was in progress.

The conventional gloss clear for printing for home appliances used a polyester resin having a number average molecular weight of 10,000 to 25,000 in order to exhibit excellent processability. As a result, a workable coating film was obtained, but there was a disadvantage that it did not exhibit a beautiful appearance and excellent sensibility. There was a limit to the brilliant color due to the fine yellowing.

Accordingly, the present inventors have conducted intensive research to overcome the above limitations, and as a result, when the number average molecular weight of the polyester resin having excellent flexibility and sensibility is adjusted to 2,000 to 8,000, the appearance and appearance are beautiful while securing the processability of PCM home appliances. The present invention has been accomplished by discovering that a coating film showing spirituality can be obtained. In particular, in the present invention, it is possible to prevent whitening of the coating film during panel processing by increasing the selectivity by using a hardening agent of the type with excellent selectivity and adjusting the use of the incompatible additive to an appropriate amount.

In the present invention, a print clear paint composition for home appliances comprising a polyester resin for PCM as a main component,

(1) 40 to 75% by weight of polyester resin,

(2) 3 to 20 wt% of the curing agent,

(3) 0.3 ~ 4% by weight of curing accelerator,

(4) 1 to 10% by weight of a polyacrylate surface modifier, and

(5) The present invention relates to a print clear paint composition for home use, which contains 10 to 25 wt% of a solvent.

The present invention is described in more detail as follows.

The polyester resin used in the present invention is a polyester resin having a hydroxyl group synthesized by condensation of a polyhydric alcohol having a aromatic, aliphatic or cycloaliphatic structure with a polyacid, having a number average molecular weight of 2,000 to 8,000, and a glass transition temperature. Is -5 to 85 ° C, and a resin having a hydroxyl group of 10 to 150 is used.

The oil-modified polyester resin in the present invention can be prepared by the condensation reaction of a polyhydric alcohol and a polyacid, wherein the polyhydric alcohol is 1.6-hexanediol, glycerin, neopentyl glycol, ethylene glycol, diethylene glycol, trimethyl Olpropane and the like can be used. As the polyacid, terephthalic acid, phthalic anhydride, adipic acid, maleic anhydride, tetrahydrophthalic anhydride, isophthalic acid and derivatives thereof can be used. Examples of the polyester resin obtained as a result of the condensation reaction are products of KCC, R00505 (number average molecular weight: 2,500, hydroxyl group 90), # 3-8 (number average molecular weight: 3,000, hydroxyl group 45), # 3-11 (number average molecular weight: 2,500, hydroxyl 58) and the like.

In the composition according to the present invention, it is preferable to use the polyester resin in an amount of 40 to 75% by weight of the total coating composition. If the content is less than 40% by weight, the processability, the sensibility and the impact resistance of the coating film are greatly reduced, 75 When it exceeds weight%, the solvent resistance and hardness of a coating film fall rapidly.

Melamine resin is used as a hardening | curing agent in this invention. A methoxy melamine resin or mixed melamine resin having a molecular weight of 300 to 1,000 can be used. It is preferable to use 3-20 weight% of melamine resin with respect to the whole coating composition, and when it is less than 3 weight%, solvent resistance and hardness fall rapidly, and when it exceeds 20 weight%, the flexibility of a coating film will fall rapidly.

Examples of methoxy-type melamine resins on the market include CYMEL-303, CYMEL-327, CYMEL-370 [CYTEC company], BE-370, BE-3717 [BIP company], RESIMINE AQ-717, RESIMINE AQ-730, RESIMINE AQ-747, RESIMINE AQ-7550 [SOLUTIA Corporation], and the like butoxy-type melamine resins include RESIMINE-750, RESIMINE-7512 [SOLUTIA Corporation], BE-630, BE-692 [BIP Corporation]. As the imino-type melamine resin, there are CYMEL-325, CYMEL-327, CYMEL-328, and the like butoxy / methoxy mixed resin CYMEL-254, CYMEL-235, CYMEL-1168, CYMEL-1156, CYMEL-1170 [CYTEC Corporation], RESIMINE-751, RESIMINE-755 [SOLUTIA Corporation], and the like.

In the present invention, methoxy type melamine resin or butoxy / methoxy mixed melamine resin is preferably used. When the imino-type melamine resin is used alone, the workability is drastically reduced. When the butoxy-type melamine resin is used alone, the compatibility with the polyester resin is lowered, the sensibility and gloss are lowered, and the hardness is lowered.

In the present invention, the curing accelerator is a raw material used to improve the density of the coating film by promoting the curing of the polyester resin and melamine, which are the main resins, and the sulfonic acid optionally shielded by amine or epoxy resin with respect to the entire coating composition. Use by weight. If the amount is less than 0.3% by weight, the solvent resistance and hardness are drastically decreased, and if it is more than 4% by weight, the flexibility of the coating film is drastically reduced.

As sulfonic acid used as a curing accelerator, there may be mentioned P-toluenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, dodecylbenzenedisulfonic acid, and in the present invention, dinonylnaphthalenesulfonic acid and P-toluenesulfonic acid are used. It is preferable.

Commercially available curing accelerators include NACURE 2107 and NACURE 2500. Examples of dodecylbenzenedisulfonic acid include NACURE 5225 and NACURE 5414. Examples of dinonylnaphthalenesulfonic acid include NACURE 1323 and NACURE 1419. , NACURE 1557, NACURE 1953, and the like, and examples of dinonylnaphthalenedisulfonic acid include NACURE 3483, NACURE 3327, and the like. In the present invention, the sulfonic acid is a material that can be dissociated by heat, it is more preferable to shield with a shielding material such as amine or epoxy resin.

The surface modifier used in the present invention is to adjust the leveling by adjusting the flow of the surface of the paint while degassing or blistering the bubble in the coating material of polyester resin and incompatible polyacrylate based resin. It is preferable to use the surface modifier in an amount of 1 to 10% by weight based on the total coating composition. If it is less than 1% by weight, the defoaming and surface flow of the paint may be drastically lowered, resulting in a deterioration of the appearance of the coating film. This is because the time-flowing property decreases and the selectivity of the coating film decreases rapidly.

Commercially available polyacrylate-based surface modifiers include BYK-340, BYK-350, BYK-354, BYK-392, URAD DD27, LA-45, CRA59002, and RESIMIX.

In the present invention, the organic solvent may be used by mixing at least one selected from esters, ketones, hydrocarbons, alcohols in a range of 10 to 25% by weight based on the total coating composition.

The coating composition of the present invention is prepared by mixing an effective amount of a polyacrylate with a surface modifier to a PCM paint containing a polyester resin and a melamine resin as a main component, and has a high gloss and processability. It is useful for the preparation of.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples are only for the understanding of the present invention, and the scope of the present invention in any sense is not limited to these examples.

Example  1-4 and Comparative example  1-4

Each Example and the comparative example paints were mix | blended with the composition ratio of following Table 1.

The paint coat was painted 3 ~ 6㎛ for FP1817-W003 (S) [KCC products], which is a polyester coat coat for home appliances. The baking conditions were 210 ~ 216 at the maximum temperature of 270 ℃, 32s, and 27HZ. It was adjusted to ℃. At this time, the coating method is BAR coating, BAR is NO. 12 was used. The base intermediate paint was coated with FJ2604-P-W720 [KCC product] 15 ~ 17㎛, baking conditions were 270 ℃, 32s, wind speed 27HZ, and the maximum temperature of the material was adjusted to 224 ~ 232 ℃. At this time, the coating method is BAR coating, BAR is NO. 24 was used. The baking oven used an automatic discharge oven manufactured by Japanese frost-heat.

The material used was a 0.45mm GI material manufactured from POSCO steel sheet, and the zinc content of the material was 87 mg / m 2. Pretreatment of the material is treated with the product of Parkarizing Co., Ltd., the throughput was applied to 20 ~ 40mg / ㎡.

The composition of Table 1 was prepared based on the solid content, and the solvent used in the paint was excluded. Solvents used in paints were used to control the flowability and viscosity required to prepare the paints.

Experimental Example

After coating the coating compositions of Examples 1 to 4 and Comparative Examples 1 to 4 BAR, a coating film was prepared by baking at 270 ° C. and 32 s in an automatic discharge oven.

Each physical property was evaluated by the following method, and the results are shown in Table 2.

Experimental Method

1. Gloss (GLOSS 60 ’)

60 ′ gloss was measured using a BYK or SHEEN polisher.

2. Processability

Processing the air at 180 degrees using an air vice at room temperature confirmed crack formation on the machining site with a 22x magnifier and evaluated as follows:

Ｘ: significant cracks occur

△: One or two point cracks occur

○: No crack

3. Solvent resistance

Methyl ethyl ketone (MEK) was applied to the cloth, and the coating was rubbed with a 1 kg load.

4. Pencil Hardness

At room temperature, the pencil lead of Mitsubishi Uni pencil was ground 90 degrees to sandpaper to make the shim flat. Standing at a 45 degree angle to the coating film was pushed forward with a 500g load a total of five experiments to confirm the scratches of the coating film. If scratches occurred more than 3 times out of 5 times, it was judged as under specification. Hardness order (highest to weakest): 2H->H->F->HB->B-> 2B

5. Chemical resistance

The coated specimens were immersed in 5% acetic acid solution, 5% hydrochloric acid solution, benzene, xylene and toluene and left at room temperature for 24 hours, after which the discoloration or swelling of the coating film was evaluated as follows:

Ｘ: coating film is discolored due to severe discoloration or swelling.

△: minute discoloration occurs or minute swelling occurs

○: no discoloration and no swelling

[Remarks]

R00505 is a polyester resin with a KCC product number average molecular weight of 2,500 and a hydroxyl group of 90.

● # 3-8 is a polyester resin having a number average molecular weight of 3,000 and a hydroxyl group of 45 under KCC's product name.

● # 3-11 is a polyester resin having a number average molecular weight of 2,500 and a hydroxyl group of 58 under the KCC product name.

● # 3-4 is KCC's product name, and is a polyester resin having a number average molecular weight of 11,500 and a hydroxyl group of 9.

2231-PE is a polyester resin with a KCC product number average molecular weight of 1,000 and a hydroxyl group of 300.

Claims (7)

(1) a resin having a hydroxyl group synthesized by condensation of a polyhydric alcohol having a aromatic, aliphatic or cycloaliphatic structure with a polyacid, wherein the polyester resin has a number average molecular weight of 2,500 to 3,000 and a hydroxyl value of 45 to 90; 40-75 wt%,
(2) 3 to 20% by weight of a methoxy or butoxy / methoxy mixed melamine resin curing agent,
(3) 0.3 ~ 4% by weight of curing accelerator,
(4) 1 to 10% by weight of a polyacrylate surface modifier, and
(5) 10-25 wt% of solvent
Printed clear paint composition for home use, characterized in that it contains. The composition according to claim 1, wherein the glass transition temperature of the polyester resin is -5 to 85 ° C. delete The composition according to claim 1, wherein the melamine resin curing agent has a molecular weight of 300 to 1,000. The composition of claim 1 wherein the curing accelerator is sulfonic acid optionally masked by an amine or epoxy resin. The composition according to claim 5, wherein the sulfonic acid is at least one selected from P-toluenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and dodecylbenzenedisulfonic acid. The composition according to claim 1, wherein the solvent is at least one selected from esters, ketones, hydrocarbons and alcohols.