KR101725784B1 - High solid and two fluid type paint composition for repairing vehicles - Google Patents

Abstract

The present invention relates to a high solids two-component coating composition for automobile repair, and more particularly, to a high solid two-component coating composition comprising 70 to 90 parts by weight of a first composition and 10 to 30 parts by weight of a second composition, Wherein the composition has a solids content of from 65 to 80% by weight, a weight average molecular weight of from 3,000 to 10,000, a number average molecular weight of from 700 to 1,500, a glass transition temperature of from 50 to 90 占 폚, 50 to 80 parts by weight of an acrylic polyol resin having 80 to 150 mg of KOH as a reference; 0.01 to 0.1 parts by weight of a curing catalyst; And 20 to 50 parts by weight of a solvent, and the second composition comprises 50 to 80 parts by weight of a polyisocyanate as a curing agent per 100 parts by weight of the second composition; And 20 to 50 parts by weight of a solvent.

Description

Technical Field [0001] The present invention relates to a high solid and two-fluid type paint composition for repairing automobiles,

The present invention relates to a high solids two-component coating composition for automobile repair, and more particularly to a high solids two-component coating composition for automobile repair, With the liquid type coating composition, it is possible to obtain an equivalent level of physical properties while reducing the environmental pollution of the existing top coat film.

Volatile Organic Compounds (VOCs) are generally organic compounds that have a sufficiently high vapor pressure under normal conditions to evaporate easily into the atmosphere. These sources include natural sources such as soil and wood, washing solvents, painting facilities, There is an artificial source such as fuel. VOCs are the cause of global warming that cause greenhouse effect. They react with nitrogen compounds in the atmosphere to cause photochemical smog and also carcinogenic. Therefore, in recent years, with the strengthening of environmental regulations, especially in developed countries, high quality is demanded. Therefore, in recent years, advanced countries are demanding high quality along with strengthening environmental regulations.

Conventionally, the top coating composition for automobile repair has been marketed as a low-priced product having excellent workability only. However, since such a product has a low solid content and a relatively high volatile solvent content, a large amount of such volatile organic compounds are discharged at the time of coating There was a problem causing environmental pollution.

It is an object of the present invention to solve the problem of environmental pollution caused by the conventional top coating composition as described above, to provide an environment-friendly property capable of improving smoothness and glossiness after painting, and further improving workability and long- By weight of the coating composition.

In order to accomplish the above object, the present invention provides a high solid two-liquid coating composition comprising 70 to 90 parts by weight of a first composition and 10 to 30 parts by weight of a second composition, wherein the first composition is a solid content An acrylic polyol resin having a content of 65 to 80% by weight, a weight average molecular weight of 3,000 to 10,000, a number average molecular weight of 700 to 1,500, a glass transition temperature of 50 to 90 ° C and a hydroxyl value of 80 to 150 mg KOH 50 to 80 parts by weight; 0.01 to 0.1 parts by weight of a curing catalyst; And 20 to 50 parts by weight of a solvent, and the second composition comprises 50 to 80 parts by weight of a polyisocyanate as a curing agent per 100 parts by weight of the second composition; And 20 to 50 parts by weight of a solvent.

The acrylic polyol resin of the present invention preferably has a weight average molecular weight of 3,000 to 10,000, a number average molecular weight of 700 to 1,500, a glass transition temperature of 50 to 90 ° C and a hydroxyl value of 80 to 150 mg KOH based on the solid weight . Because of this feature, the hardness of the coating film and the hardness of the hardened coating film are improved, so that excellent physical properties such as solvent resistance, scratch resistance and hardness can be secured. The acrylic polyol resin preferably has a solid content of 65 to 80% by weight of the resin. Such solid content plays a role of excelling in appearance such as smoothness and gloss of the coating film.

The acrylic polyol resin of the present invention requires a high solids content and a low viscosity to lower the VOC content by raising the solids content of the resin and to lower the viscosity to facilitate spraying. The content of the acrylic polyol resin is preferably 50 to 80 parts by weight based on the first composition. If the amount of the organic solvent is less than 50 parts by weight, the proportion of the organic solvent in the whole coating composition increases and the VOC content becomes high. If the amount exceeds 80 parts by weight, the viscosity of the paint may be high.

The acrylic polyol resin of the present invention is prepared by polymerizing an ethylenically unsaturated monomer, an acrylic monomer containing an acid group, a glycidyl ester, or a mixture thereof, and an acrylic monomer containing a hydroxyl group.

Examples of the ethylenic unsaturated monomer include styrene, methyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (Meth) acrylate, benzyl (meth) acrylate, isobonyl (meth) acrylate, and lauryl (meth) acrylate.

As the acrylic monomer containing an acid group, for example, (meth) acrylic acid, fumaric acid, acrylic acid dimer, maleic acid and the like can be used.

The glycidyl ester can be prepared by conducting a glycidyl ester reaction between acrylic acid, methacrylic acid, or an α-branched monocarboxylic acid and glycidol before, during, or after the polymerization reaction. The acrylic polyol resin As the monomer, a glycidyl ester reaction product between acrylic acid, methacrylic acid or Versatic 10 acid and glycidol is preferable. The glycidyl esters of versatate 10 are commercially available under the tradename " Cardura E10P ".

Examples of the acrylic monomer containing a hydroxyl group include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate and hydroxyethyl (epsilon-caprolactone) Meth) acrylate and the like can be used.

The acrylic polyol resin of the present invention has the advantages of low molecular weight, low viscosity and high solids content, but the weatherability of the coating film may be lowered due to its low molecular weight. To prevent this, it is preferable to use a monocarboxylic acid which is? -Branched as a monomer. In this case, the acrylic polyol resin preferably contains 10 to 20% by weight of the glycidyl ester reaction product of the? -Branched monocarboxylic acid based on the solid weight of the acrylic polyol resin, and when less than 10% There may be a problem in the long-term weatherability of the dried coating film, and if it exceeds 20% by weight, problems such as deterioration in solvent resistance and gloss may occur.

The acrylic polyol resin can be produced by a conventional method of polymerizing an acrylic monomer, and an acrylic polyol resin according to the present invention can be obtained by heating the above-described monomer in the presence of an initiator to a temperature of 80 to 180 ° C.

Examples of the initiator which can be used to prepare the acrylic polyol resin according to the present invention include 2,2'-azobis (2-methylbutylonitrile), 2,2'-azobisisobutyronitrile, dibenzoyl peroxide Butyl peroxybenzoate, ditertiary butyl peroxide, tertiary butyl peroxy-2-ethyl hexanoate, tertiary butyl peroxyacetate, tertiary amyl peroxy-2-ethyl hexanoate, cumyl hydroperoxide , Dicumyl peroxide, or tetramethylhydroperoxide, but the initiator that can be used in the present invention is not limited to those exemplified above.

The solvent which can be used in the polymerization reaction of the acrylic polyol resin is not particularly limited as long as it does not adversely affect the reaction. Examples thereof include aromatic hydrocarbon solvents such as toluene and xylene, methyl ethyl ketone, methyl propyl ketone, methyl butyl Ketone solvents such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, isopropyl acetate, butyl acetate, methyl cellosolve acetate, cellosolve acetate, Ester solvents such as acetate, butyl cellosolve acetate and carbitol acetate, or alcohol solvents such as n-propanol, isopropanol, n-butanol, isobutanol and tertiary butanol.

As the curing agent used in the present invention, it is preferable to use a polyisocyanate compound free from yellowing, for example, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and tetramethylxylene Diisocyanate, and the like can be used. The isocyanate of the polyisocyanate reacts with the hydroxyl group of the acrylic polyol resin to form a urethane bond. In the present invention, the content of the polyisocyanate is from 50 to 80 parts by weight based on the second composition. If the content of the polyisocyanate is less than 50 parts by weight, incomplete curing may occur when mixed with the first composition, which may cause problems in physical properties such as hardness and dryness If the amount is more than 80 parts by weight, the viscosity of the coating composition is increased, and therefore the amount of the diluting solvent used increases. As a result, the VOC content may increase.

The coating composition of the present invention is a coating composition comprising at least one of tetramethyl butane diamine, And at least one curing catalyst selected from the group consisting of:

The content of the curing catalyst used for shortening the curing time is 0.01 to 0.1 part by weight relative to the first composition. If the amount is less than 0.01 part by weight, the drying time may increase. If the amount is more than 0.1 parts by weight, There is a problem that the paint is gelled during the operation.

The solvent used in the coating composition of the present invention may be an aromatic solvent, an ester solvent, a ketone solvent or a mixture thereof. As the aromatic solvent, for example, xylene, toluene, hexane and the like can be used. As the ester solvent, for example, acetates such as butyl acetate, ethyl acetate, propyl acetate and the like can be used. , Methyl isoamyl ketone, methyl amyl ketone, and the like. The solvent is contained in an amount of 20 to 50 parts by weight for each of the first composition and the second composition. If the content of the solvent is less than 20 parts by weight, the spraying workability becomes a problem, and the leveling is not good, which affects the appearance and physical properties. If the amount exceeds 50 parts by weight, the VOC content increases and environmental problems occur. There is a problem of low adhesion and low durability.

The coating composition of the present invention may optionally contain additives in order to improve physical properties. Examples of the additives that can be used in the present invention include weathering additives, drying agents, appearance control agents, light stabilizers, antifoaming agents, ultraviolet absorbers, leveling agents, time delay agents or coupling agents. When the additive is used in the present invention, it may be added in an amount of 0.01 to 3.5 parts by weight based on the first composition.

The acrylic polyol resin used in the present invention maintains a low molecular weight and viscosity and a high solid content, and as a result, the coating composition can maintain a low molecular weight, a high viscosity and a high solid content, It is possible to minimize the amount of the organic solvent discharged into the atmosphere during coating and to maintain the existing physical properties such as solvent resistance, hardness, gloss, appearance and impact resistance . In addition, when the acrylic polyol resin contains a glycidyl ester reaction product of an? -Branched monocarboxylic acid, the problem of weatherability of the coating film attributable to low molecular weight can be overcome.

Hereinafter, the present invention will be described in detail with reference to Examples, but it should be understood that the present invention is not limited thereto.

Example  1 to 3 and Comparative Example  One

Materials Used

1) Acrylic polyol resin (a): CRT00086 # 47 manufactured by KCC (solids content: 67% by weight, number average molecular weight: 1,000, weight average molecular weight: 2600, hydroxyl value: 98 mg KOH, Tg:

2) Acrylic polyol resin (b): CRT00086, a product of KCC (solids content: 64% by weight, number average molecular weight: 1,600, weight average molecular weight: 5000, hydroxyl value: 113 mg KOH, Tg:

3) Additives: Tinuvin 1130 (light stabilizer), 292 (Ciba-Geigy) (light stabilizer), EFKA-2023 (Ciba-Geigy) (antifoaming agent), BYK 358N (BYK Chemie)

4) Solvent: butyl acetate, ketone or xylene

5) Polyisocyanate: VPLS 2025 (BAYER) (hexamethylene diisocyanate trimer)

Preparation of Coating Composition

The first and second compositions of Examples 1 to 3 and Comparative Example 1 were prepared in the compositions shown in Table 1 and Table 2, respectively, and the first composition was stirred at 1000 rpm for 20 minutes or more, To 3 were prepared by mixing the first composition and the second composition in a ratio of 3: 1, and in Comparative Example 1, the first composition and the second composition were mixed in a ratio of 2: 1.

VOC  Content and Evaluation of Physical Properties of Coating Film

2 g of each of the coating compositions obtained according to Examples 1 to 3 and the coating composition of Comparative Example 1 was taken and heated at 105 캜 for 1 hour to volatilize the solvent and calculate the remaining amount to measure the solid content (NV) The specific gravity was measured using a specific gravity cup (S224389, Sheen) at 25 DEG C, and the results are shown in Table 3.

The coating compositions of Examples 1 to 3 and Comparative Example 1 and coating films formed therefrom were subjected to the following tests at 25 ° C. The results are shown in Table 3.

1) VOC content: The formula is as follows

VOC content (g / ℓ) = (100 - mixed solid content) × 10 × mixing ratio

* Mixed solid content, mixing ratio: After mixing the first composition and the second composition, measure

2) Solvent resistance: The coating composition was coated, dried thoroughly, and then damaged with xylene. After 1 hour, the discoloration, swelling and gloss change of the coating film were visually observed.

3) Pencil hardness: tested with Mitsubishi Uni Pencil.

4) Determination of surface hardness: Measured using a pin hardness tester (Pendulum Hardness, Koenig, see ASTM D4366).

5) Appearance of coating film: Judged visually.

6) Impact resistance: Using a DUPONT tester, it was confirmed that there was no film peeling at 1/2 ", 0.5Kg, and 50cm.

As shown in Table 3, it was confirmed that the coating composition of the present invention had higher solids content and significantly lower VOC content while maintaining the solvent resistance, hardness, gloss, appearance and impact resistance of the conventional top coating composition level .

In addition, in order to evaluate the weatherability and pot life of the coating composition of the present invention, the coating composition of the present invention was prepared as follows.

Synthetic example  1: Acrylic Polyol  Preparation of Resin (A)

A thermometer and a condenser was charged with 900 g of xylene under a nitrogen atmosphere, and the temperature was raised to 160 캜. As a monomer, 1440.0 g of styrene, 144.0 g of n-butyl methacrylate, 35.0 g of methacrylic acid, 267.0 g of hydroxyethyl methacrylate, 145.0 g of hydroxypropyl methacrylate and 265.0 g of Cardura E10P, Oxy-2-ethylhexanoate (105.0 g) was added dropwise over 4 hours. Subsequently, the mixture was maintained at 165 DEG C for 2 hours, and then a mixed solution prepared by dissolving 5.4 g of initiator amyl peroxy-2-ethylhexanoate in 93.0 g of xylene was added dropwise over 10 minutes. Next, the reaction was continued for 2 hours, 20.0 g of xylene was introduced at 80 DEG C or lower, and then cooled to room temperature to obtain an acrylic polyol resin (A).

The obtained acrylic polyol resin (A) had a weight average molecular weight of 4,000, a number average molecular weight of 1,200, a hydroxyl value of 100 mg KOH / g, a solid content of 70.3% by weight, a glycidyl ester reaction product content Was 11.0 wt% based on the weight of the solid component, and was a transparent resin having a viscosity (Gardner viscosity) of Z1-Z2.

Synthetic example  2: Acrylic Polyol  Preparation of Resin (B)

A thermometer and a condenser was charged with 900 g of xylene under a nitrogen atmosphere, and the temperature was raised to 160 캜. As a monomer, 1477.0 g of styrene, 134.0 g of n-butyl methacrylate, 123.0 g of methacrylic acid, 268.0 g of hydroxyethyl methacrylate, 143.0 g of hydroxypropyl methacrylate and 265.0 g of Cardura E10P, Oxy-2-ethylhexanoate (311.0 g) was added dropwise over 4 hours. Subsequently, the mixture was maintained at 165 DEG C for 2 hours, and then a mixed solution of 5.4 g of initiator amyl peroxy-2-ethylhexanoate dissolved in 94.0 g of xylene was added dropwise over 10 minutes. Next, the reaction was maintained for 2 hours, then 19.0 g of xylene was introduced at 80 DEG C or lower and then cooled to room temperature to obtain an acrylic polyol resin (B).

The obtained acrylic polyol resin (B) had a weight average molecular weight of 4,000, a number average molecular weight of 1,000, a hydroxyl value of 90 mg KOH / g, a solid content of 72.3% by weight, and a glycidyl ester reaction product content of 10.0% by weight based on the weight of the solid content, and a viscosity (Gardner viscosity) of Z1-Z2.

Synthetic example  3: Acrylic Polyol  Preparation of Resin (C)

CRT00086 of KCC was used as the raw material (C) of the subject prepared according to the comparative synthesis example. The acrylic polyol resin was a transparent resin having a weight average molecular weight of 5,000, a number average molecular weight of 1,700, a hydroxyl value of 116 mg KOH / g, a solid content of 66.6% by weight and a viscosity (Gardner viscosity) of Z1-Z2 .

Preparation of Coating Composition

The first composition was prepared by mixing the acrylic polyol resins (A) to (C) with a curing catalyst (dibutyltin dilaurate), an additive (BYK 358N) and a solvent (xylene) as shown in the following Table 4, 5 in a ratio of 3: 1 to prepare a coating composition.

Assessment of Weatherability and Household Time

The following tests were performed to evaluate the weatherability and pot life of the above coating compositions, and the results are shown in Table 6.

1) Weatherability: Check the color difference after 500 hours of irradiation with a QUV-B lamp.

2) Pot life: Measure the time which represents the viscosity twice the initial viscosity.

As shown in Table 6, when the acrylic polyol resin of the coating composition of the present invention contains the glycidyl ester reaction product, the weatherability is further improved and the working time is prolonged to improve the workability.

Claims (12)

70 to 90 parts by weight of the first composition and 10 to 30 parts by weight of the second composition,
The first composition is a composition comprising, as a main component, a solid content of 65 to 80% by weight, a weight average molecular weight of 3,000 to 10,000, a number average molecular weight of 700 to 1,500, a glass transition temperature of 50 to 90 ° C, 50 to 80 parts by weight of an acrylic polyol resin having a solid content of 80 to 150 mg KOH; 0.01 to 0.1 parts by weight of a curing catalyst; And 20 to 50 parts by weight of a solvent,
The second composition comprises 50 to 80 parts by weight of a polyisocyanate as a curing agent per 100 parts by weight of the second composition; And 20 to 50 parts by weight of a solvent,
Wherein the acrylic polyol resin comprises from 10 to 20% by weight of the glycidyl ester reaction product of the? -Branched monocarboxylic acid based on the solids weight of the acrylic polyol resin.
High solids two-part paint composition. The acrylic polyol resin according to claim 1, wherein the acrylic polyol resin is prepared by polymerizing an ethylenically unsaturated monomer, an acrylic monomer containing an acid group, a glycidyl ester, or a mixture thereof, and an acrylic monomer containing a hydroxyl group, Coating composition. 3. The composition of claim 2 wherein the ethylenically unsaturated monomer is selected from the group consisting of styrene, methyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) (Meth) acrylate, benzyl (meth) acrylate, isobonyl (meth) acrylate and lauryl (meth) acrylate. Coating composition. The high solid two-part type coating composition according to claim 2, wherein the acrylic monomer containing an acid group is at least one monomer selected from (meth) acrylic acid, pumaric acid, acrylic acid dimer and maleic acid. 3. The high solid two-part type coating composition according to claim 2, wherein the glycidyl ester is a glycidyl ester reaction product of acrylic acid, methacrylic acid or? -Branched monocarboxylic acid. The positive resist composition according to claim 2, wherein the acrylic monomer containing a hydroxyl group is at least one selected from the group consisting of hydroxylethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, (Meth) acrylate. The high-solid two-part coating composition according to claim 1, The polyisocyanate according to claim 1, wherein the polyisocyanate is a trimeric polymer of a compound selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethylxylene diisocyanate Characterized in that the high solid two-part type coating composition comprises: The process of claim 1 wherein the curing catalyst is selected from the group consisting of tetramethyl butane diamine, bicyclooctane, dibutyl tin dilaurate, triethyl amine, diethylenetriamine, triethylenediamine, zinc octoate, bismuth carboxylate, zirconium chelate, Wherein the catalyst is at least one selected from the group consisting of calcium octoate. The high solids two-pack coating composition according to claim 1, wherein the solvent is at least one solvent selected from the group consisting of xylene, acetates and ketones. The composition of claim 1, wherein the first composition comprises Further comprising 0.01 to 3.5 parts by weight of at least one additive selected from the group consisting of weathering additives, desiccants, appearance control agents, light stabilizers, antifoaming agents, ultraviolet absorbers, leveling agents, 2-part type coating composition. delete The high solids two-part type paint according to claim 5, wherein the glycidyl ester reaction product of the? -Branched monocarboxylic acid is contained in the acrylic polyol resin in an amount of 10 to 20% by weight based on the solids weight of the acrylic polyol resin Composition.