KR20040065938A - Composition of coil coating's wrinkle type paint, and method for preparing the same and coil coating color sheet - Google Patents

Abstract

PURPOSE: A wrinkle-type paint composition for coil coating is provided to forming a film having a wrinkled surface with improved processability and weather-resistance, as compared with the film prepared by using an inorganic flatting agent. CONSTITUTION: The wrinkle-type paint composition for coil coating comprises 30-50 parts by weight of a high weather-resistant polyester-based resin paint; 3-8 parts by weight of methylated melamine resin; 0.1-1.0 parts by weight of an acid catalyst; 0.1-1.0 parts by weight of an amine catalyst; 1.0-5.0 parts by weight of an organic filler; 1.0-5.0 parts by weight of an inorganic filler; and 0.3-2 parts by weight of a polyacrylate resin. The wrinkle-type paint composition is coated in a thickness of about 20-30 micrometer based on the dried film.

Description

Composition of coil coating's wrinkle type paint, and method for preparing the same and coil coating color sheet}

The present invention relates to a method for producing a near low gloss paint using wrinkles on the surface. For more details, please refer to the melamine curable main resin of high weather resistant polyester resin and monomer, which has been used as pre-coated metal (PCM) paint. Acid catalysts, When curing using an amine catalyst, which is a catalyst, it causes a difference in curing between the inside of the coating film and the surface of the coating film, causing wrinkles on the surface of the coating film. The invention relates to a method.

The coating method of the heat-curing paint is a post-coating method for coating and drying a work-molded material and a pre-coating method for molding and coating a steel sheet coated according to the required use in advance. Post coating method is cheap coating equipment cost, there is an advantage in small quantity production, but there is a disadvantage that it is difficult to produce a uniform product and mass production. On the other hand, the pre-coating method is able to mass-produce a uniform quality product in a short time, there is an increase in the need to reduce the loss of paint, the hygiene stability of workers, environmental pollution is increasing demand. Steel plate coated by pre-coating goes through a separate process forming process after painting, so in addition to general coating properties such as workability, adhesion, durability, corrosion resistance, water resistance, etc., the high speed workability, fast curing, paint stability at high temperatures, Etc. are required. The main uses of pre-coated metal paints are divided into building exterior materials used for roofing and wall materials of buildings and home appliances (external cases such as refrigerators, microwaves, washing machines, and outdoor air conditioners). This high gloss paint is the mainstream, but for building materials, it is a classic and profound feeling, reflection of light, and ripples on the wall. (A steel plate coated with paint for pre-coating metal is used to make the wall of the building so that the steel sheet is bulging. In order to reduce the aesthetic appearance, the gloss is getting lower and lower. In general, as a method of lowering the gloss in pre-coated metal paints, a matting agent is added to a high gloss gloss (70% or more measured with a 60 ° gloss) to reduce gloss. Phosphorus silica, barium sulfate, calcium carbonate, etc. are used, and the role of this matting agent is added to the paint, giving unevenness to the surface of the coating after drying, thereby reducing the gloss by diffusely reflecting the light incident on the surface. The lower the gloss of, the more the matting agent should be added to the paint, so that the workability at the surface of the coated coating film is poor, and the chemical resistance and weather resistance are deteriorated. Therefore, the armored paint with less than 30% of gloss is caused by the matting agent included in the paint, which causes pores on the surface of the film after coating, and the moisture, air, heat, and ultraviolet rays that age the coating easily pass through it, thereby deteriorating the durability of the coating. As a result, the lower the gloss, the lower the durability of the coating.

The present inventors have studied to solve such defects, and as a result, develop a low gloss paint of 10% or less without using a conventional matting agent. For more details, refer to 30 to 50 parts by weight of the highly weather-resistant polyester resin which has been used as a pre-coated metal paint and 3 to 8 parts by weight of the resin of the melamine cured name of the monomer. 0.1 to 1.0 parts by weight of an acid catalyst as a catalyst Using 0.1 to 1.0 parts by weight of an amine catalyst, which is a catalyst, causes the difference in curing between the inside of the coating film and the surface of the coating film during curing, thereby causing wrinkles on the surface of the coating film. Wrinkles generated on the surface of the coating film is a method of diffusely reflecting light to lower the gloss of the surface of the coating film. If this is described in more detail, as shown in Figure 1 It is composed of acid catalyst and block As the amine catalyst, which is a catalyst, volatilizes on the surface of the coating film, curing proceeds by the acid catalyst. At this point, the acid catalyst Blocking with the catalyst causes no curing. As the surface is cured to form a coating film and the inside is not cured, wrinkles are formed on the surface due to the difference between the surface and the internal hardening. The catalyst is volatilized and curing of the entire coating film occurs. Since the surface of the fully cured coating film has fine wrinkles, it is generally used as a matting agent (inorganic matter). Silica, barium sulfate, calcium carbonate, etc.) can be added to lower gloss than lower gloss, so the processability is extremely excellent, and the durability and chemical resistance are excellent. Moreover, the hardness of the coating film was improved using the organic and inorganic filler, and the designability was provided. Therefore, the melamine curable resin of the high weather resistance polyester resin and monomer, which are the core raw materials of the present invention, Acid catalysts, An amine catalyst which is a catalyst. An outline of the organic and inorganic fillers and a composition containing the same will be described.

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High Weatherability Polyester Resin Composition

It is made by the condensation reaction of basic acid and alcohols, and representative basic acids include phthalic acid, phthalic anhydride, benzoic acid, isophthalic acid, telephthalic acid, tetrahydrophthalic anhydride, hexahydro phthalic anhydride, cyclo hexadicarboxylic acid, adipic acid, Dimers prepared from azelaic acid, citric acid tall oil fatty acids, trimellitic anhydride and the like, and unsaturated organic acids include maleic acid, maleic anhydride, fmaric acid, succinic anhydride and the like. In addition, representative polyols that can be used in the preparation of highly weatherable polyester resins include ethylene glycol, propylene glycol, butylene glycol, 1.6-pentanediol, diethylene glycol, neopentyl glycol, dimethyl hydropropyl, dimethyl hydroxypropio Nate, trimethanol propane, triethanol propane and the like. Resin of linear polyisocyanate is added to the polyol synthesize | combined with the said basic acid and alcohols, and is resynthesized, maintaining isothermally between 80-100 degreeC. Thus prepared resin has improved chemical resistance, processability, weather resistance, mechanical properties and the like compared to general high weatherability polyester. The number average molecular weight is 10,000-30,000, and the average functional group is adjusted to 2-4 range.

Composition of Methylated Melamine Resin

Methylated melamine resin was a hexamethoxymethylmelamine resin having a solid content of 98%, using a resin manufactured by American-made melamine manufacturer Cytec.

Acid catalyst

Paints of highly weatherable polyester and methylate melamine are used as catalysts for enhancing curing reactivity and blocking the amine catalysts and the above-mentioned acid and unblocked acid catalysts. As the acid catalyst used in the present invention, a blocked acid catalyst having a pH of 6 to 7 and an activity of 25% was used. The acid catalyst used was a product manufactured by King, USA.

Amine Catalyst

When the amine catalyst is combined with an acid catalyst, which is a catalyst, in paint, when heated, the amine catalyst on the surface volatilizes by heat, and the surface is dried first. With catalyst Due to the late drying of the inside of the catalyst, due to the difference in curing between the surface of the coating film and the inside of the coating film, wrinkles are generated on the surface of the coating film and irregularities are generated on the surface. The first amine (R-NH₂), the second amine (R-NH-R), the third amine (R₃-N) according to the number substituted by hydrocarbon, and in one molecule, depending on the number of amino groups, aliphatic amine, Divide into aromatic amines. The amine catalyst used here is an aliphatic second amine.

Organic filler

As the organic filler, nylon powder, polyacrylonitrile powder, acryl powder mainly composed of methyl methacryl, polytetrafluoroethylene powder, etc. are used. When the nylon powder is added to the coating film and heat-cured, the unevenness of the coating film is unique. Shape can be given. In particular, since nylon has a low melting point of 36 ° C., a soft uneven shape with a slippery appearance is obtained by melting during heating. Nylon powder improves the processability of the entire coating film by melting each powder particle and forming a net structure at the time of melting. However, in order to expect the effect of improving the workability by the net structure of nylon, 10% or more should be added. Since the polyacrylonitrile powder does not melt under the heating conditions of the pre-coated metal paint, a coating film having a relatively rough uneven appearance can be obtained. Polyacrylonitrile powder has a stronger resistance to friction than inorganic powders of the same size, thereby providing a slip property of the coating film, thereby preventing scratching of the coating film. Polytetrafluoroethylene powder is effective in lubricity and anti-scratch blocking. The organic filler used here uses polyacrylonitrile powder which is excellent in weatherability and imparts slip property to the surface.

Inorganic filler

Inorganic fillers used for coating are largely divided into three types. The first is an extender pigment used to increase the solid content of the paint and reduce the cost. The second is a matting agent that acts as a quencher to reduce the gloss of the paint. As a filler for granting, it is being used in different roles. The inorganic filler used in the present invention is similar to the general matting agent used to reduce the gloss of paint, but its role and composition are different. In general, the matting agent used for the matting of the paint is an amorphous porous material of silica, but in the present invention, an inorganic filler, an alumina ceramic component having excellent weather resistance, was used. The subcatalyst plays a role of stably forming wrinkles of the coating film upon dissociation.

Manufacturing process of final paint and coated steel sheet

30 to 50 parts by weight of the highly weatherable polyester resin coating material and 30 to 45 parts by weight of the solvent are dispersed in the pigment used for the paint color, and 3 to 8 parts by weight of the methylate melamine and the acid catalyst are dispersed in the dispersed mill base paint. 0.1-1.0 parts by weight of paint was prepared, and then 0.3-2 parts by weight of polyacrylate resin, which is an acrylic resin, and 0.1-1.0 parts by weight of amine, which is a minor solvent, 1.0-5.0 parts by weight of an inorganic filler and an organic filler were added thereto. Mixing to obtain a coating composition. In this continuous coating process, hot dip galvanized steel sheet, alloyed hot dip galvanized steel sheet, electrogalvanized steel sheet, hot dip galvanized steel sheet, hot dip aluminum-zinc alloy plated steel sheet, or aluminum plate with dry paint thickness of 3-8 After the coating is made to have a thickness and undergoes a process such as heating, cooling, and drying, the composition of the coating material is coated with a dry coating thickness of 20-30 μm, and then a coated steel sheet is obtained through a process such as heating, cooling, and drying. In the case where the acid catalyst and the amine as the subcatalyst were each 0.1 parts by weight or less, the wrinkles of the coating film were not well formed, and in the case of 1.0 or more, the wrinkles became large and a uniform wrinkle shape could not be obtained. In addition, when the organic and inorganic fillers were 1.0 or less, wrinkles were unstable, and when 5.0 or more, the coating film became hard, resulting in poor workability. The film thickness was not well formed wrinkles at less than 20 microns, and when the film thickness is more than 30 microns, the coating film boils due to heat, thereby losing its function as a coating film. Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is not limited thereto.

<Example 1>

30 to 50 parts by weight of the highly weatherable polyester resin coating material and 30 to 45 parts by weight of the solvent are dispersed in the pigment used for the paint color, and 3 to 8 parts by weight of the methylate melamine and the acid catalyst are dispersed in the dispersed mill base paint. 0.1-1.0 parts by weight of paint was prepared, and then 0.3-2 parts by weight of polyacrylate resin, an acrylic resin, and 0.1-1.0 parts by weight of amine, which was a minor solvent, and 1.0-5.0 parts by weight of an inorganic filler and an organic filler were added thereto. Mixing was carried out to obtain a green paint composition. The coating material is degreased, washed with water, and dried on a hot dip galvanized steel sheet. The primer coating is then coated with a dry coating thickness of about 5 μm in a continuous roll coating process. After heating, cooling, and drying to 220 ° C., the composition of the pleated paint is coated with a dry coating thickness of about 20-30 μm as a top coat, and then heated, cooled, and dried to reach a material surface reaching temperature of 210 to 250 ° C. The corrugated paint and the coated steel sheet of the present invention were prepared.

Wrinkle Paint TestⅠ

It is possible to confirm the measured value of the gloss and the two-dimensional surface roughness of the coated film after adjusting the coating thickness at the time of coating by evaluating the wrinkle-like paint in a short time. The dry film thickness was measured between 60 micron and 30 micron, and the gloss and secondary aid were measured at 60 ° at 1m / sec. The results are shown in Table 1.

Wrinkle Paint Test II

After evaluating the corrugated paint in a short time, it is possible to confirm the measured value of the glossiness and the two-dimensional surface roughness of the package after adjusting the wind speed during the coating. At a thickness of 20 microns, a typical automatic discharge oven used for coil coating coating experiments was used to measure 60 ° mirror gloss and two-dimensional roughness at 1m / sec and 5m / sec. The girl is shown in Table 2.

Wrinkle Paint Test III

As a method of evaluating corrugated paints in a short period of time, it is possible to confirm the measured value of gloss and two-dimensional surface roughness of the coated film after adjusting the wind speed according to the temperature received by the material. At a thickness of 20 microns, a typical automatic discharge oven used for coil coating coating experiments was used to measure 60 ° mirror gloss and two-dimensional roughness at 1m / sec and 5m / sec. The results are shown in Table 3.

Wrinkle Paint Test IV

In order to check the weather resistance of the corrugated paint, we compared the weather resistance with the coated steel sheet to make the coated steel sheet in order to compare with the fluorine resin coating material having the best weatherability as the coil coating paint. The results are shown in Table 4. In addition, the experimental results for the pencil hardness, impact, processability, Gloss (60 °) are also shown in Table 5.

<Example 2>

In <Example 1>, it carried out similarly to Example 1 except having replaced the high weather-resistant polyester-based resin material instead of 100 weight part of polyester resins.

<Example 3>

In <Example 1>, it carried out similarly to Example 1 except having replaced the high molecular polyester-type high polymer resin (molecular weight 20,000-40,000) instead of 100 weight part of polyester resin.

Table 1 Glossiness and Two-Dimensional Roughness by Wrinkle Coating Thickness

1) P.M.T: 220 ± 5 ℃ × 45 sec

2) Dry film thickness: PRIMER 5 ㎛ + TOP 25 ㎛

3) Wind speed: 2.5m / s

4) In two-dimensional surface roughness

Ra: The value obtained by integrating the highest height and the lowest depth of the surface irregularities over a certain length range by the measured length.

Rt: The sum of the highest height and the lowest depth of surface irregularities over a certain length range.

Table 2 Glossiness and Two-Dimensional Roughness by Corrugated Paint

1) P.M.T: 220 ± 5 ℃ × 45sec

2) Dry film thickness: PRIMER 5㎛ + TOP 25㎛

3) in two-dimensional surface roughness

Ra: The value obtained by integrating the highest height and the lowest depth of the surface irregularities over a certain length range by the measured length.

Rt: The sum of the highest height and the lowest depth of surface irregularities over a certain length range.

Table 3 Gloss and Two-dimensional Roughness by P.M.T of Pleated Paint

1) Dry film thickness: PRIMER 5㎛ + TOP 25㎛

2) Wind speed: 2.5m / s

3) Drying Time: 45sec

4) In two-dimensional surface roughness

Ra: The value obtained by integrating the highest height and the lowest depth of the surface irregularities over a certain length range by the measured length.

Rt: The sum of the highest height and the lowest depth of surface irregularities over a certain length range.

Table 4 Comparison of weathering resistance and corrosion resistance between corrugated paint and fluorine resin

Table 5 Property Test Results

The present invention does not use an inorganic matting agent, which has been generally used to lower the surface gloss of a coated film as a paint, and causes a curing difference between the inside of the coating film and the surface of the coating film during curing, thereby causing wrinkles on the surface of the coating film. The wrinkles generated on the surface of the coating film are diffusely reflected by the light to reduce the glossiness of the surface of the coating film. Since the coating film of this coating material does not use an inorganic quencher compared with the coating film of the existing coating material, the workability is improved and the weather resistance is improved among the physical properties of the coating film.

Claims (5)

Coil coating to create wrinkles on the coating film after coating by adding acid catalyst and amine to polyester resin, or high weathering polyester resin, or high polymer polyester high polymer resin, methylated melamine resin Wrinkle-type coating composition for, and its manufacturing method. 2. The composition of the corrugated coating material for coil coating and its manufacturing method according to claim 1, wherein 0.1 to 1.0 parts by weight of acid catalyst and 0.1 to 1.0 parts by weight of argin are added. The composition according to claim 1, wherein the inorganic filler and the organic filler are added in an amount of 1.0 to 5.0 parts by weight. The composition according to claim 1, wherein 0.3 to 2 parts by weight of polyacrylate resin, which is an acrylic resin, is added. The method of claim 1, wherein the thickness of the coating film coated with the electrical coating composition is a dry coating thickness of about 20 ~ 30㎛, the composition of the corrugated coating material for coil coating and its manufacturing method.