KR20130093851A - Method of preparing acryl-modified polyester resin composition and top clear paint composition including the resin - Google Patents

Abstract

PURPOSE: A manufacturing method of acrylic modified polyester resin composition is provided to have high hardness, elasticity, and excellent exterior acrylic modified polyester resin composition. CONSTITUTION: A manufacturing method of acrylic modified polyester resin composition comprises a step of manufacturing polyester resin by condensing with polyatomic acid with polyhydric alcohol including 95 mole% of diol and 5-10 mole% of triol, and a step of reacting 50-70 weight% of polyester resin and 30-50 weight% of acrylic monomer. Moreover, a clear paint composition comprises the manufactured acrylic modified polyester resin composition, curing agent, solvent, and additive.

Description

METHOD OF PREPARING ACRYL-MODIFIED POLYESTER RESIN COMPOSITION AND TOP CLEAR PAINT COMPOSITION INCLUDING THE RESIN}

The present invention relates to a method for producing an acrylic modified polyester resin composition and a clear coating composition using the same, and more particularly, to a method for producing an acrylic modified polyester resin composition exhibiting excellent physical and chemical properties and to a vehicle top clear coating composition using the same. It is about.

Automotive top clear coating compositions require excellent mechanical, chemical and appearance. Mechanical properties indicate flexibility, which indicates the degree of flexibility after spray coating, pencil hardness, impact resistance, and adhesion of the painted surface, and the chemical properties indicate water resistance, alkali resistance, weather resistance, and the like. Sensitivity, land feeling, and film smoothness according to discrimination.

In general, the oil-based coating composition for automobile coating is used an acrylic resin, a polyester resin, or the like, or resins in which the resins are variously modified and combined. Most of the paints having the resin as a composition are thermosetting paints used in admixture with a curing agent.

The acrylic resins and polyester resins are mainly used as paints for automobile top clears, except for products requiring special paint properties. In particular, acrylic resins having excellent mechanical and chemical properties are most frequently used.

Automotive top clear paints require high elasticity and high hardness. Typical automotive top clear paints include acrylic resins as main components, melamine resin compounds as crosslinking agents, and paint compositions prepared by adding small amounts of additives such as curing catalysts, antifoaming agents, and leveling agents.

The coating composition used a polyester resin having a low linear glass transition temperature (Tg) in order to give high elasticity so that cracks do not occur after coating the steel sheet. Since the linear polyester resin has a small molecular weight and a large hydroxyl value, there is an advantage in that compatibility with the solvent is excellent. By the way, when the linear polyester resin is used, the coating film is excellent in elasticity and excellent in screening, appearance, and the like when painted on an automobile tower, but the hardness of the coating film is lowered.

Since the resin composition for automobile top clear paints has important properties such as hardness, water resistance, and gloss, aromatic acids and alcohols having excellent durability are used as main raw materials in producing polyester resins. However, when only the aromatic monomer is used, the gloss is good, but high hardness is difficult to secure and water resistance tends to be weak.

The technical problem of the present invention is to provide a method for producing an acrylic modified polyester resin composition that can secure high hardness, high elasticity and excellent appearance.

Another object of the present invention is to provide a clear coating composition having excellent physical properties by using the acrylic modified polyester resin composition described above.

A method for producing an acrylic modified polyester resin composition for realizing the above object of the present invention is to prepare a polyester resin by condensation polymerization of a polyhydric alcohol containing 90 to 95 mol% diol and 5 to 10 mol% triol with polybasic acid. And a step of copolymerizing 50 to 70% by weight of the polyester resin and 30 to 50% by weight of the acrylic monomer monomer.

In one embodiment, the condensation polymerization of the polyhydric alcohol with polybasic acid may be performed by adding 5 to 6 ppm of at least one metal selected from the group consisting of calcium, cesium, tin, manganese, magnesium, and antimony.

In one embodiment, the step of copolymerizing the polyester resin and the acrylic monomer monomer is at least one selected from the group consisting of tert-butyl peroxide, benzoyl peroxide and tert-butyl peroxy-M-isopropyl benzene It can be carried out in the presence of a catalyst.

In one embodiment, the step of copolymerizing the polyester resin and the acrylic monomer monomer may be carried out by dropping the acrylic monomer monomer to the polyester resin in the temperature range of 100 ~ 140 ℃.

In one embodiment, the polybasic acid is 30 to 40 mol% of at least one anhydrous acid selected from the group consisting of phthalic anhydride, tetrahydrophthalic anhydride and maleic anhydride, adipic acid, succinic acid, azelaic acid and sebacic acid 30 to 40 mol% of at least one aliphatic acid selected from and 20 to 30 mol% of at least one aromatic acid among isophthalic acid and terephthalic acid.

In one embodiment, the diol is 20 to 30 mol% of 1,4-butanediol, 20 to 30 mol% of 1,6-hexanediol, 20 to 30 mol% of neopentyl glycol, and 5 to 10 mol% of trimethol propane And 10 to 20 mol% of diols obtained by addition polymerization of ethylene oxide to hydrogenate bisphenol A.

In one embodiment, the acrylic monomer is 8 to 10% by weight of normal butyl methacrylate, 5 to 7% by weight of styrene, 5 to 7% by weight of 2-hydroxyethyl methacrylate, Acryster ester having the formula -SL 7-9 wt% and methacrylic acid 1-2 wt%.

<화학식 1>

&Lt; Formula 1 >

In an embodiment, the polyester resin may have a hydroxyl value of 45 to 65 mgKOH / g, an acid value of 3 mgKOH / g or less, a glass transition temperature of 0 to 15 ° C., and a weight average molecular weight of 3,000 to 4,000.

In one embodiment, the acrylic modified polyester resin may have a weight average molecular weight of 5,500 ~ 7,500, hydroxyl value of 50 ~ 60mgKOH / g, acid value of 3mgKOH / g or less and a glass transition temperature of 10 ~ 20 ℃ range.

In order to achieve the above object of the present invention, a polyhydric alcohol comprising 90 to 95 mol% of diol and 5 to 10 mol% of triol is condensation-polymerized with polybasic acid to prepare a polyester resin and the polyester resin 50 to Provided is a clear coating composition comprising an acrylic modified polyester resin composition, a curing agent, a solvent, and an additive prepared according to a method comprising copolymerizing 70 wt% and 30-50 wt% of an acrylic monomer monomer.

In one embodiment, the acrylic modified polyester resin may have a weight average molecular weight of 5,500 ~ 7,500, hydroxyl value of 50 ~ 60mgKOH / g, acid value of 3mgKOH / g or less and a glass transition temperature of 10 ~ 20 ℃ range.

In one embodiment, the coating composition is 10 to 30% by weight of the acrylic modified polyester resin composition, 15 to 30% by weight of the acrylic resin, 10 to 25% by weight of the sagging control agent (SCA), 20 to 40% by weight of the curing agent, It may comprise 1 to 5% by weight solvent and additives.

In one embodiment, the additive may include 0.2 to 2.0 wt% of an acid catalyst, 0.1 to 1.0 wt% of an antifoaming agent, 0.2 to 2.0 wt% of a leveling agent, and 1.5 to 3.0 wt% of a light stabilizer.

The top clear coating composition prepared by using the acrylic modified polyester coating composition prepared according to the method of the present invention has an excellent hardness and elasticity of a level suitable for a use, and thus a coating film having a stable and excellent appearance can be realized.

Hereinafter, the present invention will be described in more detail. While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are further described in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In this application, the terms "comprises" or "having" are intended to indicate that there is a feature, ingredient, step, process, composition, or combination thereof described on the specification, one or more other features or ingredients, It is to be understood that it does not preclude the presence or possibility of addition of steps, processes, compositions or combinations thereof.

Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, the present invention will be described in detail.

Acrylic modified polyester resin composition according to an embodiment of the present invention is a polyhydric alcohol containing 90 to 95 mol% diol and 5 to 10 mol% triol condensation polymerization with polybasic acid to prepare a polyester resin, the polyester resin It is prepared by copolymerizing 50 to 70% by weight and 30 to 50% by weight of the acrylic monomer monomer.

The coating composition comprising the acrylic modified polyester resin as described above complements physical properties such as adhesion, flexibility, appearance and impact resistance of the polyester resin and physical properties such as hardness, chemical resistance, water resistance and solvent compatibility of the acrylic monomer. Has excellent physical properties.

Hereinafter, the present invention will be described in more detail.

Acrylic modified polyester resin composition and its manufacturing method

Method for producing an acrylic modified polyester resin composition according to an embodiment of the present invention is as follows. Condensation polymerization of a polyhydric alcohol comprising 90 to 95 mol% of diol and 5 to 10 mol% of triol with a polybasic acid to prepare a polyester resin; and 50 to 70 wt% of the polyester resin and 30 to 50 wt% of an acrylic monomer monomer. Copolymerizing the%.

The polyester resin is prepared by reacting a polybasic acid with a polyhydric alcohol. The polyhydric alcohol may provide excellent physical properties of high hardness in a state in which elasticity is secured by containing 5 to 10 mol% of a triol.

The polyhydric alcohol contains 90 to 95 mol% diol. When the content of the diol used in the production of the polyester resin is less than 90 mol% of the polyhydric alcohol, the elasticity of the polyester resin may be weak, whereas when the content of the diol exceeds 95 mol%, the acrylic acid finally prepared This is because physical properties such as chemical resistance and hardness of the modified polyester resin may be weak.

According to one embodiment of the invention, the diol is 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, methylpropanediol, methylpentanediol, 1,6-hexanediol, propylene glycol, diethylene Glycols, neopentyl glycols, diols obtained by addition polymerization of ethylene oxide to hydrogenate bisphenol A, and the like. These may be used alone or in combination of two or more thereof.

Preferably the diol is 20-30 mol% of 1,4-butanediol, 20-30 mol% of 1,6-hexanediol, 20-30 mol% of neopentylglycol, 5-10 mol% of trimetholpropane and hydrogenate 10-20 mol% of diols which addition-polymerized ethylene oxide in bisphenol A are included.

More preferably, the diol is 65 to 75 mol% of neopentyl glycol having excellent mechanical properties, 20 to 30 mol% of 1,6-hexanediol having excellent flexibility, and a diol obtained by addition polymerization of ethylene oxide to hydrogenate bisphenol A having excellent adhesion. Contains 5-15 mol%.

In addition, the polyhydric alcohol includes 5 to 10 mol% of triol. If the content of the triol used for the production of the polyester resin is less than 5 mol% of the polyhydric alcohol, the hardness improvement of the acrylic modified polyester resin is insignificant, whereas if it exceeds 10 mol%, the viscosity of the acrylic modified polyester resin This is because a large amount of organic solvent is required to prepare the paint. According to an embodiment of the present invention, the triol includes trimethylolpropane and the like.

According to one embodiment of the invention, the polybasic acid is 30 to 40 mol% anhydrous acid, including at least one selected from alicyclic acid consisting of phthalic anhydride, tetrahydro phthalic anhydride and maleic anhydride, adipic acid, succinic acid, azelaic acid And 30 to 40 mole% of aliphatic acid including at least one selected from aliphatic acid consisting of sebacic acid and 20 to 30 mole% of aromatic acid including at least one of isophthalic acid and terephthalic acid. In particular, when an alicyclic acid other than an aromatic acid alone is used in an appropriate ratio, the reaction zone capable of introducing an acrylic monomer and reacting the addition can be sufficiently provided.

The polybasic acid includes 30 to 40 mol% of at least one anhydrous acid selected from the group consisting of phthalic anhydride, tetrahydrophthalic anhydride and maleic anhydride. The acid anhydride is an element that imparts high hardness and water resistance to the acrylic modified polyester resin because the acrylic monomer is copolymerized to the carbon double bond present in the anhydrous acid.

When the anhydrous acid is less than 30 mol% of the polybasic acid, the acrylic monomer may not copolymerize well with the polyester resin produced by the polymerization of the polybasic acid and the polyhydric alcohol, and thus an acrylic modified polyester resin having excellent hardness and water resistance may not be obtained. On the other hand, when the anhydrous acid exceeds 40 mol% of the polybasic acid, the use amount of the aliphatic acid which gives a relatively elasticity is reduced, which makes the final resin weak and elastic.

The polybasic acid includes 30 to 40 mol% of at least one aliphatic acid selected from the group consisting of adipic acid, succinic acid, azelaic acid, and sebacic acid. When the aliphatic acid is less than 30 mol% of the polybasic acid, the elasticity of the acrylic modified polyester resin may be weak, whereas when the aliphatic acid is more than 40 mol%, the hardness of the acrylic modified polyester resin may be lowered.

The polybasic acid includes 20 to 30 mol% of an aromatic acid including isophthalic acid and terephthalic acid. When the aromatic acid is less than 20 mol% of the polybasic acid, the hardness, durability, and solvent resistance of the acrylic modified polyester resin may be lowered. On the other hand, when the aromatic acid exceeds 30 mol%, the elasticity and bendability of the acrylic modified polyester resin may be reduced. Can be.

According to an embodiment of the present invention, the polycondensation reaction of the polybasic acid and the polyhydric alcohol may be performed under at least one metal compound catalyst selected from the group consisting of calcium, cesium, lead, tin (Sn), manganese, magnesium and antimony. have. Preferred addition amounts range from 5 to 6 ppm.

According to one embodiment of the present invention, the polyester resin prepared using the polybasic acid and the polyhydric alcohol has a hydroxyl value of 45 ~ 65mgKOH / g, acid value of 3mgKOH / g or less, the glass transition temperature is 0 ~ 15 ℃ range It is preferable that the weight average molecular weight is in the range of 3,000 to 4,000.

When the hydroxyl value is less than 45 mgKOH / g, the viscosity of the paint prepared by the coating composition of the present invention is high, and when it exceeds 65 mgKOH / g, the molecular weight of the coating composition including the acrylic-modified polyester resin is low and mechanical properties may be lowered. Can be. In addition, when the acid value of the polyester resin exceeds 3mgKOH / g, the water resistance and chemical resistance of the acrylic modified polyester resin may be lowered.

In addition, when the weight average molecular weight of the polyester resin is less than 3,000, the strength of the formed coating film is lowered, so that the durability is weak. When the weight average molecular weight is more than 4,000, the viscosity of the polyester resin composition is increased, so that the amount of the organic solvent added in the preparation of the paint increases, It may be fragile in appearance. In addition, if the glass transition temperature is less than 0 ℃, the hardness of the formed coating film is lowered, whereas if the glass transition temperature exceeds 15 ℃, the elasticity, appearance and stiffness of the coating composition comprising the acrylic modified polyester resin may be weak. Can be.

Preparation of Acrylic Modified Polyester Resin

The acrylic modified polyester resin of this invention is manufactured by copolymerizing an acryl monomer with said polyester resin.

According to one embodiment of the invention, the acrylic monomer is preferably used 30 to 50% by weight relative to the prepared polyester resin. When the acrylic monomer is used in less than 30% by weight relative to the polyester resin, the hardness and water resistance of the acrylic modified polyester resin may be weak. On the other hand, when the acrylic monomer is used in excess of 50% by weight, self-polymerization may occur between the acrylic monomer monomers, resulting in excessively high viscosity and opacity of the acrylic modified polyester resin.

According to an embodiment of the present invention, the acrylic monomer is methyl methacrylate, normal butyl acrylate, normal butyl methacrylate, ethyl acrylate, ethyl methacrylate, styrene, Acryster ester represented by the following formula (1)- SL, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid, acrylic acid and the like. These may be used alone or in combination of two or more thereof.

More preferably the acrylic monomer is 8 to 10% by weight of normal butyl methacrylate, 5 to 7% by weight of styrene, 5 to 7% by weight of 2-hydroxyethyl methacrylate, Acryster ester-SL represented by the following formula (1) It comprises 7 to 9% by weight, methacrylic acid 1 to 2% by weight.

&Lt; Formula 1 >

According to one embodiment of the present invention, the step of copolymerizing the acrylic monomer to the polyester resin may be carried out under a catalyst. By adding the catalyst, a copolymerization reaction between the synthesized polyester resin and the acrylic monomer can be facilitated. Examples of the catalyst include tert-butyl peroxide, benzoyl peroxide, tert-butyl peroxy-m-isopropyl benzene and the like. The catalysts may be used alone or in a mixture of two or more thereof. It is preferable to use two or more catalysts because the copolymerization ratio is higher.

The step of copolymerizing the polyester resin and the acrylic monomer monomer may be carried out by dropping the acrylic monomer monomer to the polyester resin in the temperature range of 100 ~ 140 ℃.

The acrylic modified polyester resin prepared by the above method is polymerized acrylic monomer to a polyester resin having a conjugated double bond, thereby modifying the acrylic modified polyester resin for high hardness and high elasticity automotive top clear paint. It can be obtained as a composition.

The obtained acrylic modified polyester resin composition may have a weight average molecular weight of 5,500 to 7,500, a hydroxyl value of 50 to 60 mgKOH / g, an acid value of 3 mgKOH / g or less, and a glass transition temperature of 10 to 20 ° C.

The prepared acrylic modified polyester resin composition may be mixed with a curing agent, a solvent, and the like, and additives may be added as necessary to prepare a clear coating composition.

Hereinafter, an acrylic modified polyester resin and a coating composition including the same, which are prepared according to the method of manufacturing the acrylic modified polyester resin of the present invention, will be described in detail. However, the present invention is not limited to the following embodiments and may be implemented in other forms. The embodiments introduced herein are provided to make the disclosed contents more complete and to sufficiently convey the spirit and features of the present invention to those skilled in the art.

&Lt; Example 1 >

In a four-necked flask, 28.5 mol% of isophthalic acid, 39.2 mol% of tetrahydrophthalic anhydride, and 36.9 mol% of adipic acid, 403 g of polybasic acid, 5 mol% of trimethylolpropane, 58 mol% of neopentyl glycol, 20 mol% of methylpropanediol, and 304 g of polyhydric alcohol having 17 mol% of 1,6-hexanediol was reacted at an equivalence ratio (alcohol / acid) = 1.1 to 1.2 / 1. 0.3 g of dibutyltin oxide was added to the reaction as a catalyst. Thereafter, stirring was performed in a nitrogen input state. In order to remove condensed water flowing out as the reaction proceeds, but to minimize the loss of alcohol, the temperature of the condenser was gradually increased to 240 ° C. while maintaining the maximum temperature of 102 ° C. or less. It was cooled when the target viscosity (Y-Z) and acid value (3 mgKOH / g or less) were obtained, maintaining 240 degreeC. At 180 ° C. or less, 95 g of solvent cocosol 100 (K-100, SK Co., Ltd.) and 35 g of PMA were added and diluted.

The polyester resin composition obtained above was heated up at 135 degreeC, and 30 weight% of acrylic monomers were added with respect to the solid content contained in the polyester resin composition obtained above, ie, 70 weight% of a polyester resin. That is, 6.2% by weight of styrene, 7% by weight of Acryster SL, 9.5% by weight of normal butyl methacrylate, 6.3% by weight of hydroxyethyl methacrylate, and 1% by weight of methacrylic acid were added dropwise at a uniform rate for about 3 hours. It was. After dropping, the mixture was maintained for 1 hour, 0.02 g of dibutyl butyl peroxide and 0.01 g of benzoyl peroxide were added two times at an interval of 1 hour, and maintained for 2 hours. Then, the reaction was terminated to obtain an acrylic modified polyester resin. The obtained acrylic modified polyester resin was found to have a weight average molecular weight of 5,500-7,500, a hydroxyl value of 50-60 mgKOH / g, an acid value of 3 mgKOH / g and a glass transition temperature of 10-20 ° C.

<Example 2>

Performed in the same manner as in Example 1 but changing the amount of use of the components as shown in Table 1 to prepare an acrylic modified polyester resin according to the present invention.

&Lt; Comparative Example 1 &

In a four-necked flask, 487 g of polybasic acid of 65 mol% of isophthalic acid, 25 mol% of tetrahydrophthalic anhydride and 10 mol% of adipic acid, 10 mol% of ethylene oxide addition bisphenol A, 10 mol% of trimethylolpropane, and 30 mol of neopentyl glycol 442 g of polyhydric alcohols of%, 30 mol% methylpropanediol and 20 mol% of 1,6-hexanediol were reacted in an equivalent ratio (alcohol / acid) = 1.05 to 1.0 / 1. 0.3 g of dibutyltin oxide was added as a catalyst. Thereafter, stirring was performed in a nitrogen input state. In order to remove condensed water flowing out as the reaction proceeds, but to minimize alcohol loss, the temperature of the condenser was gradually increased to 240 ° C. while maintaining the maximum temperature of 102 ° C. or less. It was cooled when the target viscosity (Z-Z1) and acid value (5 mgKOH / g or less) were obtained, maintaining 240 degreeC. At 180 ° C. or below, 95 g of solvent Cosol 150 (K-150, SK Co., Ltd.) and 5 g of xylene were added and diluted. The polyester resin produced was found to have a weight average molecular weight of 8,500, a hydroxyl value of 62 mgKOH / g, an acid value of 4 mgKOH / g and a glass transition temperature of 23 ° C.

Comparative Example 2

Performed in the same manner as in Comparative Example 1 but changing the amount of the component as shown in Table 1 to prepare a polyester resin according to the comparative example.

Table 1 summarizes the ingredients used in Examples 1 and 2 and Comparative Examples 1 and 2 (g).

TABLE 1

Preparation of Coating Composition

In order to prepare a coating composition comprising the polyester resin composition obtained in Examples 1 to 2 and Comparative Examples 1 to 2 of Table 1, and to examine the coating and coating film properties of the coating composition, Examples 3 to 6 and Comparative Example 3 The coating composition was prepared as in -4, and its characteristic was examined.

<Example 3>

60% by weight of the acrylic modified polyester resin prepared in Example 1 and 40% by weight of an organic solvent were mixed to prepare an acrylic modified polyester resin composition. A mixed liquid of xylene and cocosol-150 was used as the organic solvent.

20 wt% of the acrylic modified polyester resin composition prepared above, 25 wt% of acrylic resin, 20 wt% of SCA, 35 wt% of melamine curing agent, 0.1 wt% of acid catalyst, 0.5 wt% of antifoaming agent, 0.4 wt% of leveling agent, light stabilizer 1.5 A paint composition was prepared using wt% and solvent 2 wt%. As a melamine curing agent, norumin-1286 (Noru Holdings) was used, and as a solvent, Cocozol-100 (K-100, SK Co., Ltd.), Cocozol-150 (K-150, SK Co., Ltd.) and xylene Mixed solution was used.

<Example 4>

Prepared in substantially the same manner as in Example 3, using the acrylic modified polyester resin prepared in Example 2 as an acrylic modified polyester resin to prepare a coating composition.

<Example 5>

Prepared in substantially the same manner as in Example 3, but the coating composition was prepared by adjusting the proportion of the resin as shown in Table 2.

<Example 6>

Prepared in substantially the same manner as in Example 3, but as shown in Table 2 to adjust the ratio of the resin and additives to prepare a coating composition.

&Lt; Comparative Example 3 &

The coating composition was prepared in substantially the same manner as in Example 3, but using the polyester resin prepared in Comparative Example 1.

&Lt; Comparative Example 4 &

The coating composition was prepared in substantially the same manner as in Example 3, but using the polyester resin prepared in Comparative Example 2.

The components used in Examples 3 to 6 and Comparative Examples 3 to 4 and the amounts used (wt%) are summarized in Table 2.

<Table 2>

Each component used in Table 2 is as follows.

1): Noro Creek 0804 (Arc Resin: Noro Holdings))

2): NOROESTER 0033 (ACRIC modified polyester resin: NOROHOLDINGS)

3): NORU ANTI-SAG (flow prevention Acryric resin: NORO HOLDINGS)

4): Solvent K-100 (SK)

5): Solvent XYLENE

6): Hardener Norumin 1286 (Noruf Holdings)

7): Defoamer SN354 (Sannov Cosa)

8): UVA EVERSORB80 (EVERLIGHT CHEMICAL)

9): HALS (hindered amine light stabilizer)

10): Surface adjuster DISPALONLC901 (Kusmoto Chemical)

11): Surface regulator KF-69

12): Curing Catalyst CATALYST 6000 (Mitsui Chemical)

13): slip agent BYK310 (product made by BYK)

As a method of performing a top clear coating for automobiles using the prepared coating composition, it may be coated by a conventional method such as air spray and electrostatic coating, and the coating film thickness is preferably formed to be about 30 to 40 μm as a cured coating film. Do. Typical coating systems apply oily or water-based base coats on the electrodeposition and intermediate coatings within 15 to 20 microns and then within 5 to 10 minutes of setting time (in water, 2 to 5 minutes at 60 to 80 ° C). Water-drying with blow) The top clear can be coated and heated at 140-150 ° C for 20-40 minutes to crosslink and cure both coating layers at once.

Physical property evaluation of coating film

In order to evaluate the physical properties of the coating film, the coating composition prepared in Examples 3 to 6 and Comparative Examples 3 to 4 was applied to the electroplated CR steel sheet to form a coating film.

Zinc phosphate-treated steel sheets were used as CR steel sheets, and epoxy electrodeposition paints (KED 2500), waterborne intermediate paints (DWP-300), and water-based top coats (DWB3000) were used for the undercoat. After electrodeposition and intermediate coating, apply 15 ~ 20 microns of water-based base coat on dried film, then perform water-drying with HOT AIR BLOW at 60 ~ 80 ℃ for 2 ~ 5 minutes, then apply top clear coating composition and apply about 140 ~ 150 It heated at about 20 to 40 minutes and crosslinked and hardened both coating layers at once.

The film properties of each of the prepared specimens were evaluated. Evaluation items and conditions were as follows.

Hardness: It was evaluated using Mitsubishi and Chinese pencil.

Gloss: measured at 20 Hz and 60 Hz with MICRO-TRI-GLOSSMETER from BYK.

Appearance (Spilarity): The size and appearance quality of the surface curvature were measured by analyzing the structure spectrum of the painted surface using a wave-scan DOI.

Adhesiveness: About 100 1mm / 2mm cross cuts were produced and peeled off using a tape, and then there was a check that there was a surface peeled off.

Impact resistance: Using a Dupont (Dupont) impact machine using a weight of about 500g, the impact was measured by applying a shock at a height of about 30cm or more.

Flex resistance: When the base was bent in a round steel having a circumference of 3/16 inch, it was confirmed that the coating film was free of cracks and peeling.

Water resistance: I was immersed for about 20 days in hot water of about 40 ~ 50 ℃, and then visually confirmed the abnormality of the coating film.

Chipping resistance: After keeping for 3 hours at -20 ℃, impact with a 50g stone of crushed stone at a pressure of 4bar to check the peeling state.

Weather resistance: Q-PANEL's QUV instrument and ATLAS's WOM test instrument were evaluated for 2000 hours after appearance color abnormalities.

Flowability: It was evaluated according to the standard test method of workability considering line conditions.

Pinhole property: evaluated according to the standard test method of workability considering the line conditions.

The evaluation criteria were ◎ excellent, ○ good, △ moderate and ㅧ poor.

<Table 3>

As can be seen in Table 3, the coating film formed by using the coating composition (Examples 3 to 6) including the acrylic modified polyester resin composition of the present invention was prepared using the coating compositions prepared by Comparative Examples 3 and 4. It can be seen that it is excellent in pencil hardness and flexibility compared to the formed coating film. That is, the coating films of Comparative Examples show similar performance as the coating films prepared using the coating composition of the present invention in terms of appearance and workability, but the flexibility is weak and the physical properties are deteriorated. On the other hand, in the case of the coating film manufactured using the coating composition of Examples 3-6, it can confirm that flexibility and hardness show the outstanding performance simultaneously.

As described above, according to the present invention, by copolymerizing an acrylic monomer to a polyester resin having a double bond, the physical properties such as adhesion, flexibility, appearance and impact resistance of the polyester resin and hardness, chemical resistance, water resistance and solvent of the acrylic monomer An acrylic modified polyester resin for automobile top clear coating compositions exhibiting excellent physical properties such as compatibility, etc. can be prepared.

By producing the automotive top clear coating composition using the acrylic modified polyester resin, it is possible to form a coating film having excellent hardness and elasticity and excellent appearance suitable for automotive top clear coating composition applications. Thus, a stable coating film can be formed by manufacturing the coating composition for automobile top clear which is excellent in physical and chemical reasons.

In addition, the clear coating composition according to the present invention is a UNIVERSAL TYPE that can be used in parallel when the lower paint type is an oil paint and a water-based paint.

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

Claims (15)

Preparing a polyester resin by condensation polymerization of a polyhydric alcohol including 90 to 95 mol% of diol and 5 to 10 mol% of triol with polybasic acid; And
50 to 70% by weight of the polyester resin and 30 to 50% by weight of the acrylic monomer monomer copolymerization method of producing an acrylic modified polyester resin composition. The method of claim 1, wherein the condensation polymerization of the polyhydric alcohol with a polybasic acid is performed by adding 5 to 6 ppm of at least one metal selected from the group consisting of calcium, cesium, tin, manganese, magnesium, and antimony. Manufacturing method. The method of claim 1, wherein the step of copolymerizing the polyester resin and the acrylic monomer monomer comprises at least one selected from the group consisting of tert-butyl peroxide, benzoyl peroxide and tert-butyl peroxy-m-isopropyl benzene. A process for the production which is carried out in the presence of a catalyst. The method of claim 1, wherein the step of copolymerizing the polyester resin and the acrylic monomer monomer is carried out by dropping the acrylic monomer monomer to the polyester resin in a temperature range of 100 ~ 140 ℃. According to claim 1, wherein the polybasic acid is 30-40 mol% of at least one anhydrous acid selected from the group consisting of phthalic anhydride, tetrahydro phthalic anhydride and maleic anhydride, adipic acid, succinic acid, azelaic acid and sebacic acid 30 to 40 mol% of at least one aliphatic acid selected from and at least one aromatic acid 20 to 30 mol% of isophthalic acid and terephthalic acid. According to claim 1, wherein the diol is 20 to 30 mol% of 1,4-butanediol, 20 to 30 mol% of 1,6-hexanediol, 20 to 30 mol% of neopentyl glycol, 5 to 10 mol% of trimethol propane And 10 to 20 mol% of diols obtained by addition polymerization of ethylene oxide to hydrogenate bisphenol A. According to claim 1, wherein the acrylic monomer is 8 to 10% by weight of normal butyl methacrylate, 5 to 7% by weight of styrene, 5 to 7% by weight of 2-hydroxyethyl methacrylate, Acryster ester having the formula -7 to 9% by weight of SL and 1 to 2% by weight of methacrylic acid.

&Lt; Formula 1 >
The method according to claim 1, wherein the polyester resin has a hydroxyl value of 45 to 65 mgKOH / g, an acid value of 3 mgKOH / g or less, a glass transition temperature of 0 to 15 ° C, and a weight average molecular weight of 3,000 to 4,000. . According to claim 1, wherein the acrylic modified polyester resin has a weight average molecular weight of 5,500 ~ 7,500, hydroxyl value of 50 ~ 60mgKOH / g, acid value of 3mgKOH / g or less, and the glass transition temperature is in the range of 10 ~ 20 ℃. Manufacturing method. Preparing a polyester resin by condensation polymerization of a polyhydric alcohol including 90 to 95 mol% of diol and 5 to 10 mol% of triol with polybasic acid; And
50 to 70% by weight of the polyester resin and 30 to 50% by weight of the acrylic monomer monomer, a clear coating composition comprising an acrylic modified polyester resin composition, a curing agent, a solvent and an additive prepared according to the method. The method of claim 10, wherein the acrylic modified polyester resin has a weight average molecular weight of 5,500 ~ 7,500, hydroxyl value of 50 ~ 60mgKOH / g, acid value of 3mgKOH / g or less and the glass transition temperature is characterized in that the range of 10 ~ 20 ℃ Coating composition. The coating composition according to claim 10, wherein the polyester resin has a hydroxyl value of 45 to 65 mgKOH / g, an acid value of 3 mgKOH / g or less, a glass transition temperature of 0 to 15 ° C, and a weight average molecular weight of 3,000 to 4,000. . The acrylic monomer according to claim 10, wherein the acrylic monomer is 8 to 10% by weight of normal butyl methacrylate, 5 to 7% by weight of styrene, 5 to 7% by weight of 2-hydroxyethyl methacrylate, and an acrylic ester having the following Chemical Formula 1. 7 to 9% by weight of SL, and 1 to 2% by weight of methacrylic acid.

&Lt; Formula 1 >
The coating composition according to claim 10, wherein the coating composition is 10 to 30% by weight of acrylic modified polyester resin composition, 15 to 30% by weight of acrylic resin, 10 to 25% by weight of SCA, 20 to 40% by weight of solvent, 1 to 5% by weight of the solvent, and A paint composition comprising an additive. The coating composition according to claim 10, wherein the additive comprises 0.2 to 2.0 wt% of an acid catalyst, 0.1 to 1.0 wt% of an antifoaming agent, 0.2 to 2.0 wt% of a leveling agent, and 1.5 to 3.0 wt% of a light stabilizer.