KR19990061667A - Powder Coating Composition - Google Patents

Abstract

The present invention relates to a powder coating composition, and more particularly, in the construction of a powder type coating containing a thermosetting resin such as an epoxy resin and a polyester resin as a main component, a polyester resin, an epoxy resin, and an acryl as a base material. Resins and the like, including curing agents, catalysts, leveling agents, wetting agents, degassing agents, dispersants, antioxidants or light stabilizers, polyvalent basic acids and acid anhydrides, organic and A powder composition containing an inorganic filler and the like in a predetermined composition. In the case of system coating (multilayer coating) using this, it has excellent chip resistance and impact resistance, as well as smoothness and sharpness, and has a beautiful appearance. Of improved powder coating composition which can be usefully applied to low automobile body and parts coating The.

Description

Powder Coating Composition

The present invention relates to a powder coating composition, and more particularly, in the construction of a powder type coating containing a thermosetting resin such as an epoxy resin and a polyester resin as a main component, a polyester resin, an epoxy resin, and an acryl as a base material. Resins and the like, including curing agents, catalysts, leveling agents, wetting agents, degassing agents, dispersants, antioxidants or light stabilizers, polyvalent basic acids and acid anhydrides, organic and A powder composition containing an inorganic filler and the like in a predetermined composition. In the case of system coating (multilayer coating) using this, it has excellent chip resistance and impact resistance, as well as smoothness and sharpness, and has a beautiful appearance. Of improved powder coating composition which can be usefully applied to low automobile body and parts coating The.

In general, a conventional paint in liquid form prepared by dissolving a colorant and a pigment in a volatile diluent and an organic solvent, when the paint is applied, an organic solvent is volatilized to form a coating film. However, by using volatile organic solvents and diluents, there is a risk of poisoning or fire due to the volatilization of solvents, and it is necessary to adjust the viscosity of the paint to prevent wrinkles or flow during film formation. There are various problems in use, such as the need for drainage and treatment facilities for paints that are not recovered.

Currently, volatile organic compounds released in various forms affect the atmosphere in a variety of forms. Among them, VOC (Volatile Organic Solvents) is a country that uses VOC reduction as the main policy means for air quality management by influencing the environment and health due to tropospheric ozone pollution, stratospheric ozone layer destruction and global warming, depending on the type and reaction type in the atmosphere. Is increasing. VOC material refers to a hydrocarbon compound that generates ozone which causes photochemical smog through photochemical reactions with nitrogen oxides and other chemicals in the atmosphere. There is an increasing use of paints that can minimize the release of volatile organic compounds. For example, paints aimed at reducing solvents include high-solids paints with high solids content, water-based paints with organic solvents substituted for water, and powder-free solvent-based paints. The use of powder coatings is increasing. In addition, environmentally friendly coatings using paints that can reduce organic solvents as much as possible are preferred not only for legal regulations, but also to reduce environmental treatment facilities and operating costs. Most preferred in that it is not.

On the other hand, as a conventional paint to be painted on a vehicle, a liquid paint composed of a diluent, a solvent, an additive, a pigment, and an extender pigment has been widely used. However, since the diluent and the solvent are volatile organic compounds, as mentioned above, volatilization occurs during the formation of the coating film, so that the environment is polluted and there is a risk of human poisoning or fire due to the volatilization of the solvent. In order to prevent orange peel effect and sagging effect, liquid paints have to be adjusted in viscosity and a separate device and effort are required to treat unrecovered paints. Will occur. In addition, when using a synthetic resin having a high molecular weight as a component of the colorant, since the solubility of the colorant in the solvent is small, the available colorant is limited to a low molecular weight material, and the physical properties of the resulting coating film become weak, resulting in a new type of vehicle paint. Necessity is emerging.

The paint developed as this part is a powder paint, which is sprayed with a powder paint on the coated object and then heated to melt the powder to form a coating film. Powder type paints were first used in Europe in the 1950s by powder flow deposition, and in the 1960s, electrostatic powder coating machines were developed to provide thermosetting powders with excellent properties and durability using epoxy resins and polyester resins. Paint is mostly used.

In terms of quality, these powder coatings can form a thick coating film in one coating, have good processability, and do not contain organic solvents. Therefore, there is no fire air pollution, and the reclaiming of paints is possible. It has a feature that saves money. In addition, it is easy to manage the coating conditions, and there is no solvent volatilization during painting, so it does not need strict control of environmental conditions and skilled coating technology, does not need to adjust viscosity, etc. .

However, on the other hand, there is a problem that the smoothness is poor and the thin film coating of the liquid coating level is difficult, the high temperature heat curing type, the color replacement takes a long time, and the color tone is dropped.

However, the regulation of volatile organic solvents emitted from automobile manufacturing process is one of the important items in the situation where environmental regulations are strengthened. To meet these standards, alternatives such as water-soluble paints and powder coatings without organic solvent emission are required. The need for paint is increasing.

Therefore, under such regulations, the demand for water-soluble and powder coating is emphasized in automobile manufacturing plants, and the use of such paints will increase in the future. Among them, powder coatings are powder coatings for automotive coatings because of the advantages described above. This is drawing attention and research on the use of this is drawing attention.

In the present invention, it is possible to obtain a coating system and a coating composition having desired physical properties by using various types of resins and hardeners in order to obtain appropriate physical properties for each coating type, and in particular, equivalent or superior physical properties compared to existing types. It was found that the optimum physical properties can be obtained by changing the paint composition according to the change or change of the coating system.

The present invention uses a polyester resin, an epoxy resin, an acrylic resin, and the like as a thermosetting resin which is a basic material in constituting a powder-based coating material composed mainly of thermosetting resins such as epoxy resins and polyester resins. , A powder composition containing a leveling agent, a wetting agent, a pinhole inhibitor, a dispersant, an antioxidant or a light stabilizer, a polyvalent basic acid and an acid anhydride, an organic and an inorganic filler in a predetermined composition, and the system coating (multilayer coating) In the case of having excellent chip resistance and impact resistance, as well as excellent smoothness and clarity, and has a beautiful appearance, an object of the present invention is to provide an improved powder coating composition that can be usefully applied to automotive body parts and parts coating.

It is another object of the present invention to provide a method of applying the powder coating composition as described above to the coating.

The present invention provides a powder coating composition containing a thermosetting resin such as an epoxy resin and a polyester resin as a main component,

(1) Epoxy resins having two or more oxirane groups as base materials, polyester resins having two or more carboxyl end groups, polyester resins having two or more hydroxyl groups, two or At least one thermosetting resin selected from an acrylic resin having more than one hydroxyl functional group, an acrylic resin having two or more carboxyl functional groups, and an acrylic resin having a GMA (glycidyl methacrylate) functional group;

(2) at least one curing agent selected from an oxirane epoxy curing agent, an isocyanate curing agent having an isoprene diisocyanate blocking agent, an isocyanurate curing agent and a polyvalent basic acid;

(3) an additive comprising a catalyst, a polyacrylate leveling agent, a wetting agent, a dispersant, an antioxidant, and a light stabilizer;

(4) organic and inorganic pigments; And

(5) It is characterized by having a polycarboxylic acid and an acid anhydride.

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

The present invention uses polyester resins, epoxy resins, acrylic resins, and the like as main component resins, including additives such as curing agents, catalysts, leveling agents, wetting agents, pinhole inhibitors, dispersants, antioxidants, or light stabilizers, and polyvalent basic acids. A powder composition containing acid anhydride, organic and inorganic fillers and the like in a predetermined composition.

The thermosetting resin used as the base material in the present invention includes a polyester resin having a carboxyl end group, a polyester resin having a hydroxyl end group, an epoxy resin having an oxirane functional group, an acrylic resin having a carboxyl end group, and a hydroxyl group. An acrylic resin having an end group and an acrylic resin having a GMA end group can be used.

In the present invention, the epoxy resin containing two or more oxirane groups can be used that has an epoxy equivalent of 450 to 2,000 equivalents and a softening point of 60 to 130 ℃ range, the two or more carboxyl groups The polyester resins having an acid value of 20 to 85 and a Tg of 30 to 85 ° C., preferably in the range of 40 to 60 ° C., may be used, and the polyester resin having two or more hydroxyl groups may be hydrated. Those having a hydroxyl group of about 30 to 120 and having a Tg of 30 to 85 ° C., preferably 40 to 60 ° C., and having an acid value of about 20 to 50 with an acrylic resin having two or more carboxyl groups can be used. Tg is 30-85 degreeC, Preferably the thing of the range of 35-60 degreeC can be used, It is an acrylic resin which has the said two or more hydroxyl groups, and hydroxyl group is 30-120. And Tg is 30-85 degreeC, Preferably it has a range of about 35-60 degreeC, The acrylic resin which has the said 2 or more glycidyl methacrylate functional group is equivalent, about 300-800 degree. Having a Tg of 30 to 80 ° C, preferably 35 to 60 ° C, and having two or more oxirane functional groups, having an epoxy equivalent of 350 to 2,000, preferably Has a range of 450 to 1,200 and Tg has a range of 20 to 90 ° C, and preferably has a range of about 30 to 70 ° C.

As the curing agent, an epoxy resin curing agent having an oxirane group, a TGIC (triglycidyl isocyanurate) curing agent having an oxirane group and a curing agent having an isocyanate group or a curing agent having a blocked isocyanate group, and a curing agent having a carboxyl end group In addition, aliphatic and aromatic curing agents can be used, including epoxides and anhydride reactors.

A polyacrylate-based leveling agent for improving leveling, a wetting agent for improving melting and appearance, a dispersant for improving dispersibility, an antioxidant for improving paint durability, and a light stabilizer may be used.

In addition, organic pigments and inorganic pigments may be used as the pigment for color, and inorganic pigments such as titanium dioxide, calcium carbonate, silicate and the like, and organic pigments having strong colorability may be pigments representing red, blue, green, or the like. Can be used.

As such, the components of the present invention will be described in more detail as follows.

The polyester resin applied in the present invention is a polyester resin having a carboxyl functional group and a hydroxyl functional group, and has a number average molecular weight of 1,500 to 12,000, preferably 3,000 to 9,000. At this time, the glass transition temperature of polyester is 35-85 degreeC, More preferably, 40-65 degreeC is preferable. If the temperature is too low, the storage stability of the paint is lowered. If the temperature is too high, the storage stability is good, but the leveling is poor, so that a suitable glass transition temperature is preferable.

Looking at the manufacturing method of such a polyester resin is as follows.

First, as the acid, dihydric acid or more polyhydric acid is used alone or in combination, and alcohol is also used alone or in combination. The monomers used are preferably aliphatic polyhydric alcohols and aromatic polyhydric alcohols, aliphatic and aromatic polycarboxylic acids, and the like, and aromatic diols and aliphatic and aromatic polycarboxylic acids, more preferably dicarboxylic acid condensation reaction products. At this time, the polyol used is ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, butylene glycol, 1,6-hexanediol, neopentyl glycol, cyclohexane dimethanol, trimethylol propane, hydrogenation Bisphenol A and the like can be used. Among them, preferred aromatic polyols are diols such as ethylene glycol, propylene glycol, butylene glycol or 1,6-hexanediol. Suitable polycarboxylic acids are aromatic dicarboxylic acids and aliphatic dicarboxylic acids, more preferably adipic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, and the like, and phthalic anhydride and hexa Hydrophthalic anhydride, tetrachloro phthalic anhydride, pyromeric anhydride and the like. Of these, long-chain acids are particularly preferred for smoothness, clarity and gloss of the coating.

The acrylic resin used in the present invention has a number average molecular weight in the range of 3,000 to 15,000, the glass transition temperature is in the range of 30 to 85 ℃, styrene, acrylate, unsaturated hydrocarbon monomers, amide monomers, acrylic acid derivatives And acrylic resin having a glycidyl group, a hydroxyl group, and a carboxyl group derivative at the terminal thereof using a halogenated ethylenically unsaturated monomer or the like.

According to the present invention, according to the monomer composition of the acrylic resin affects the physical properties of the paint and look at it as follows.

If the content of the styrene monomer is 20% by weight or more, the crosslinking density of the formed coating film is high, and the physical properties such as impact resistance, abrasion resistance, and solvent resistance are excellent, and when the content is less than 60% by weight, the appearance, that is, smoothness and sharpness, is excellent. . Therefore, 20 to 60 weight% is preferable. In addition, the styrene component is preferably 10 to 20% by weight, and this component contributes to storage stability of the paint and gloss and smoothness of the coating film. However, if the content is too large and 30 wt% or more, the coating film is yellowed, yellowing resistance is lowered and weather resistance is poor.

On the other hand, as the acrylic monomer, methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, stearyl acrylate, cyclohexyl acrylate, benzyl One or more selected from acrylic acid derivatives such as acrylate, phenyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, 1,4-butanediol monoacrylate and dimethylaminoethyl acrylate In this case, the amount that can be contained in the total acrylic resin is preferably 50 to 80% by weight. This is because the adhesion to the base material should be 50% by weight or more, and when contained in excess of 80% by weight, the hardness of the coating film may be increased and the appearance of the coating film may be reduced, and more preferably 5 to 75% by weight. desirable.

In addition, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, stearyl Methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, 1,4-butanediol monomethacrylate Monomers having a long chain alkyl group, such as methacrylic acid derivatives such as dimethylaminoethyl methacrylate, may be used. In this case, the coating film is smoothed and the glossiness is used when it is used at 50% by weight or more, preferably 60% by weight or more. A rising and clear coating can be obtained.

Moreover, unsaturated hydrocarbon monomers, such as vinyl ester (alpha) -methylstyrene, vinyl toluene, t -butyl styrene, vinyl anisole, vinyl naphthalene, divinylbenzene, and chlorostyrene, such as vinyl acetate and a vinyl propionate; Nitriles such as acrylonitrile and methacrylonitrile; Amide monomers such as acrylamide, methacrylamide, vinylamide, N -methylol acrylamide and N -methylol methacrylamide; Vinyl chloride, vinylidene chloride, vinyl fluoride, monochlorotrifluoroethylene, tetrafluoroethylene, chloropentyl halogenated ethylenically unsaturated monomers; Α-olefins or dienes having 4 to 20 carbon atoms such as ethylene, propylene, isoprene and butadiene; Alkyl vinyl ethers such as lauryl vinyl ether; Nitrogen containing vinyl, such as vinylpyrrolidone and 4-vinylpyrrolidone, etc. can be used.

The acrylic monomers may be used alone or in combination of two or more thereof. The acrylic resin may be prepared by a polymerization method such as solution polymerization, suspension polymerization, bulk polymerization or emulsion polymerization. Preference is given to using a polymerization method.

Here, the reaction initiators are benzoyl peroxide, t -butyl hydroxide, t -butylperoxy-2-ethylhexanoate, t -butylperoxybenzoate, di- t -butylperoxide, cumene hydroperoxide And compounds such as peroxides such as dicumyl peroxide or lauroyl peroxide or azo compounds such as azobisisobutyronitrile and azobismethylvalenonitrile. As the solvent, an aliphatic or aromatic hydrocarbon solvent or a monoalcohol solvent having a polar group such as n-butane is used, and it depends on the reflux and the raw material. The final resin removes the solvent under vacuum.

In addition, to control the molecular weight may be used a polymerization regulator of the cuptan system, as a regulator n-butyl merethane, n- amyl mercantane, n- dodecyl mercantane, t- boomer cuptan or 3-epoxypropyl mer Cup shot etc. are used.

In the present invention, the acrylic resin having a carboxyl functional group may use acrylic acid, methacrylic acid, Icaconic acid, maleic acid, fumaric acid, monohydric alcohol and a combined monoester of fumaric acid and maleic acid.

In addition, an acrylic resin having a hydroxyl functional group can be produced using monomers such as hydroxyethyl acrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypropyl acrylate and the like.

Acrylic monomers having amino functional groups include t -butylaminoethyl methacrylate and t -butylamineethyl acrylate.

Examples of the curing agent of the hydroxyl functional acrylic resin include amine hardening agents hexamepoxymethylolmelamine, trimethololmelamine, trimethylether, hexamethylolmeryl hexamethylether, hexamethylolmelamine or trimethylolbenzoguanamine. Isocyanate hardeners can be used.

Moreover, in this invention, various hardening | curing agents are used and when it sees the characteristic as a hardening | curing agent which has an isocyanate derivative, a solid compound is mainly used, melting | fusing point is 60-110 degreeC, and preferable thing is 70-110 degreeC. Block polyisocyanate compounds are obtained by the reaction of blocking agents such as phenol, carolactone, alcohol and the like. Aromatic, aromatic cyclic or aliphatic polyisocyanates include isoprene diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tolyene diisocyanate, xylene diisocyanate, tolyene Diisocyanate and the like, and preferred are isoprene diisocyanate, hexamethylene diisocyanate, hydrogenated dipenyl methane diisocyanide, hydrogenated xylene diisocyanate and hydrogenated tolyene diisocyanate.

As blocking agents used for the isocyanate reaction, oximes include methylethyl ketoxime, methyl-n-amyl ketoxime, acetone oxime, cyclohexanone oxime or caprolactam. Other blocking agents that may be used include malonic esters and other aliphatic, cycloaliphatic, aliphatic and alkylmonoalcohols. Other blocking agents include the lower aliphatic alcohols methyl, ethyl, chloroethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, nonyl, 3,3,5-trimethylhexanol, decyl, lauryl alcohol and the like. Blocking agents for phenolic compounds include phenol and phenolic substituents, but phenolic substituents should not be used for adverse effects during coating. Others include dibutyl amine and tetraethylamine, ethylethanolamine.

Also, in the present invention, the aliphatic dibasic acid uses a saturated or unsaturated aliphatic dibasic acid having two or more carbon atoms, which react with an oxirane functional group to form a coating film. Examples of such dibasic acids include succinic acid, glutaric acid, adipic acid, fimer acid, azelaic acid, sebacic acid, dodecanenoic acid, brassidic acid, itaconic acid, maleic acid, citraconic acid, and ecosanic acid. In the present invention, dodecanenoic acid can be preferably used.

In addition, acid anhydrides may also be used in the present invention, which is used for improving the curing density or giving flowability or flexibility of the coating film. As the acid anhydride, one having at least one acid anhydride mainly in a solid phase at room temperature, and having a melting point of 40 to 150 ℃ can be used. Examples of such acid anhydrides are phthalic anhydride, p -chlorophthalic anhydride, hexahydrophthalic anhydride, tetratrorophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, tetrabromophthalic anhydride, cyclohexane 1, 2-dicarboxylic anhydride, cyclopentane-1,2-dicarboxylic anhydride, dodecyl succinic anhydride, succinic anhydride, maleic anhydride, methyl succinic anhydride, azelaic anhydride, polyadipic anhydride, poly Azelaic anhydride, polyceva anhydride, polydodetanoic anhydride, polyeicoanic anhydride, and the like. The acid anhydride is preferably used in 1 to 15% by weight based on the resin solid content, but excess of 15% by weight inhibits leveling, surface hardness and surface tacky, preferably 3 to 10% by weight Preferred examples are polyeico-acid noic anhydride and polydodecane noic anhydride.

In addition, the present invention uses a UV absorber and antioxidant to improve the external durability after painting. As antioxidants, for example, phenolic antioxidants, organic sulfur antioxidants or phosphite antioxidants can be used. Phenolic antioxidants include alkylphenols, monoalkylenedialkylphenols, dialkylenetrialkylphenols, traalkylphenols, bisphenol monosulfites, polyphenols, and the like. Among them, preferred phenolic antioxidants include 4,4'-butylidenebis (3-methyl-6-t-butylphenol) and tetrakis [methylene-3- (3 ', 5'-di-t-butyl- 4'-hydroxyphenyl) propionne] methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- ( 3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate. Organic sulfur antioxidants include 3,3'-thiodipropionic acid, pentaerythritol tetrakis (3-laurylthiopropionate), 2-mercapdobenzimidazole and the like. Examples of phosphite antioxidants include trifenylphosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, and cyclic neopentanetetrabisbis (octadecyl phosphite). have. Such antioxidants are available as commercially available products from Shivagai or other additive companies under the trademarks TINUVIN and IRGANOX, and if UV absorbers are used, they are based on the weight of the resin. 1.5 to 6% by weight, preferably 1.5 to 3% by weight is preferably present in the composition. If less than 1.5% by weight, the durability and yellowing of the coating film occurs, and if it is more than 6% by weight, the curability is poor and the mechanical strength is lowered.

In addition, the powder coating composition of the present invention may include a catalyst to increase the crosslinking ratio in forming the coating film. The baking temperature of such catalysts is usually 121-177 ° C. Suitable catalysts include quaternary ammonium salts, quaternary phosphonium salts, phosphines, imidazoles and metal salts, for example tetrabutylammonium chloride, bromide or yo Odide, ethyltriphenylphosphonium acetate, octosan tin, triphenylphosphine, 2-methylimidazole, 2-C ₁₁ -imidazole, 2-C ₁₇ -imidazole and dibutyltin dilaurate There is this. The preferred amount of catalyst in the composition is 0.1 to 3% by weight, preferably 1.5 to 3% by weight, based on the weight of the resin solids. If the amount is less than 0.1% by weight, the curing property is lowered and the mechanical properties are lowered. If the amount is less than 3% by weight, the appearance is degraded and the coating film is softened.

In addition, pigments added to impart a suitable color to the powder coating composition of the present invention can be included in the coating composition typically 5 to 50% by weight, preferably 10 to 40% by weight based on the total weight of the powder coating composition. have. If less than 5% by weight, concealment is lowered. If it is more than 50% by weight, the appearance is degraded and the coating film is brittle. Suitable pigments for powder coating compositions include organic or inorganic pigments. Representative inorganic pigments include zinc oxide, carbon black, titanium oxide, antimony hoist, black iron oxide, red iron oxide, red lead, cadmium yellow, zinc sulfate, lithopone. Inorganic pigments such as barium sulfite, lead sulfide, barium carbonate, white lead, alumina white, aluminum hydroxide, calcium carbonate, silicon oxide, and silicon carbonate. Organic pigments include azo type pigments, benzoimidazolone pigments, phthalocyanine pigments (green and blue), thioindigo pigments, anthraquinone pigments, flavatron pigments, indanthrene pigments, anthra pyridine pigments, and pyrantrone pigments. , Isoinflinone pigment, pinylene pigment, pyridone pigment, quinacridone pigment, etc. are used and many other kinds are used.

The coating composition may also contain certain other additives that are typically added to the powder coating composition. In particular, it may contain a pinhole inhibitor to release volatiles from the coating film during firing and a flow regulator to prevent crater formation during the finishing process. Benzoin is a very preferred pinhole inhibitor and is used in amounts ranging from about 0.3 to 3% by weight, based on the total weight of the composition. If less than 0.3% by weight, the pinhole and appearance of the coating film are poor, and if it exceeds 3% by weight, the yellowing of the coating film becomes severe and tacky, and about 0.5 to 1.5% by weight is particularly preferable.

Suitable flow regulators in the present invention include polylauryl acrylate, polybutyl acrylate, poly (2-ethylhexyl) acrylate, poly (ethyl-2-ethylhexyl) acrylate, poly lauryl methacrylate, polyisodecyl Acrylic polymers such as methacrylate and the like can be used and converted acrylate types can also be used. The flow regulator may also be an unsaturated polymer such as polyethylene glycol or polypropylene glycol and esters of fluorinated fatty acids, for example esters of polyethylene glycol having a molecular weight of at least 2,500 and perfluorooctanoic acid. In addition, polymer siloxanes having a molecular weight of 1,000 or more can also be used as flow regulators, for example polydimethylsiloxane or poly (methylphenyl) siloxane. Such a flow regulator is used in an amount of 0.5 to 5% by weight, based on the coating composition. If the content is less than 0.5% by weight, the appearance becomes poor, and when it is more than 2.5% by weight, the paint becomes tacky, the hardness of the coating film is lowered, and the physical properties are lowered. In particular, it is preferable to use 0.5 to 2.5% by weight of the flow agent.

The case of manufacturing a medium powder coating composition for a vehicle using the components used in the composition of the present invention as described above can be illustrated as follows as an example.

Thermosetting powder coating composition according to the present invention is 30 to 85% by weight resin (epoxy resin, polyester resin, acrylic resin), 5 to 40% by weight curing agent, 5 to 50% by weight pigment, 0.5 to 2.5% by weight flow agent, blocking 0.3 to 0.5 wt% of the inhibitor, 0.5 to 1.5 wt% of the light stabilizer, 0.2 to 0.5 wt% of the benzoin, 0.1 to 0.5 wt% of the electrostatic stabilizer, 0.1 to 0.5 wt% of the antioxidant, and the like, and then 2 to 6 in the mixer. After homogeneous premixing for minutes, the process is followed by uniform melt mixing using a melt mixer such as kneader or extruder at a temperature in the range of 60 to 140 ° C. This mixing process can be repeated two or more times.

After cooling the mixture in a chiller roller, the mixture was ground using a sample mill (SAMPLE MILL) or ACM 2L and passed through a 200 mesh sieve to obtain a powder coating having an average particle size of 10 to 75 μm. The particle size of the powder coating is also one of the most important factors in forming the appearance of the powder coating film. The smaller the particle size, the smoother the appearance during firing. However, if there are a lot of low particles of 10 ㎛ or less, it is difficult to transfer the paint quantity to the powder conveying pipe, and agglomeration occurs during the transfer, which adversely affects the painting workability. Care should be taken and adjustments should be made so that the distribution range is not wide. The preferred average particle size is in the range of 15 to 25 μm, in which case a good appearance can be obtained.

As a method of coating the powder coating on the substrate, there is a method such as electrostatic coating method (corona coating method, tribostatic coating method), flow deposition method, etc., and the method is pre-treated with zinc phosphate coating. After cation electrodeposition, the powder coating prepared on the specimen with the electrodeposition coating film is coated by electrostatic coating method (corona coating method) or tribostatic coating method. Then, the powder-coated substrate is baked for about 10 to 50 minutes at a temperature of 120 to 200 ° C. The coating film obtained through such a process is excellent in leveling, gloss, mechanical properties, chemical resistance, corrosion resistance, weather resistance, and the like, so that it can be appropriately applied to home appliances or automobile bodies and parts thereof.

If the powder coating composition is applied to a vehicle, the solvent-based base and the solvent-type clear coat may be coated on the above-described coating film or the water-soluble base and the solvent-type clear coat may be coated to be baked at 130 to 160 ° C. for 20 to 40 minutes. In order to form a coating film, the physical properties of the formed coating film satisfy the required physical properties of the vehicle body coating film.

Alternatively, after coating the solvent type or the aqueous type base, the powder type clear coat is applied and baked for 20 to 40 minutes at 130 to 160 ° C. to form a coating film. Get beautiful appearance and physical properties. The description of the water-soluble base coat is disclosed in Korean Patent Publication Nos. 96-22883, 95-19326, 95-18153, 94-37419, 94-38157, 94-38158, 94- It is mentioned in 37418. In particular, the base coat applied to the car body coating is important for gloss, hiding power, decorative effects, weather resistance, repainting, and can be effectively performed to improve workability and obtain an excellent coating film. Basecoats containing water-soluble metallic pigments have a more beautiful appearance than a solvent-based coating to achieve an external effect and a beautiful appearance. 10 minutes after stabilization of the base and then flash off at 80 ° C. for 10 minutes, followed by powder coating and baking at 130 to 160 ° C. for 20 to 40 minutes to obtain not only an excellent coating film but also an excellent physical property in a short time. have.

In the present invention, the solvent-based base and the solvent-type clear coat are wet on wet, the water-soluble base and the solvent-type clear coat are dried on wet, solvent-based base on the specimen having the powder coating film formed thereon. The powder clearcoat is coated with dry on wet or water-soluble base and powder clear coat with dry on wet, and baked at 130 to 170 ° C. for 20 to 40 minutes to obtain a final coating film.

When manufacturing a top coat powder composition for a vehicle using the components used in the composition of the present invention in the same manner as another example can be illustrated as follows.

50-90 wt% of powder coating resin, 10-50 wt% of curing agent, 0.3-1.5 wt% of additive, 0.5-1.5 wt% of benzoin, 0.2-3 wt% of light stabilizer, 0.3-0.5 wt% of antioxidant After that, the mixture is uniformly premixed in a mixer for 2 to 6 minutes and then melt mixed uniformly using a melt mixer such as a kneader or an extruder at a temperature range of 60 to 110 ° C. This melt mixing process may be repeated two or more times. After the mixture is cooled in a chiller roller, the mixture is ground using a sample mill (Sample Mill, manufactured by Fugi Powdal) and then manufactured through about 200 mesh sieves. Alternatively, ACM 2L (Test Mass Mill, Hoso Kawasaki) was used to prepare a powder coating having an average particle size of 8 to 20 μm.

Particle size of the powder coating is one of the most important factors in forming the appearance of the powder coating film, the smaller the particles can make the appearance smooth during firing, the lower particle size can be used to obtain a good coating film. However, if there are a lot of low particles of 5 ㎛ or less, it is difficult to transfer the paint in the quantity of powder conveying pipe and agglomeration occurs during the transfer, which adversely affects the painting workability. In addition, when the particle size of 35 ㎛ or more increases, the appearance of the paint is lowered, so the particle size management of the paint should be carefully controlled and the distribution range should not be widened. A more preferable average particle size is in the range of 10 to 20 µm, so that a good appearance can be obtained.

In addition, in order to manufacture finely divided powder coating, a commonly used micron separator or a classifier [Turbo Classifier, TC-III S and TC-III C (Nishin Engine Earring Co., Ltd.) or DS classifier [DS-2 S and DS -2 C (Nippon Pneumatic Co., Ltd.) can be used to control the particle size and particle size distribution desired.

The prepared powder coating is coated on a cold rolled iron plate with zinc phosphate film pre-treated specimens and coated with a powder coating primer surfacer or a water-soluble intermediate or solvent intermediate (KCC) on a specimen coated with cation electrodeposition. Or apply a powder coating on top of two coats of baking. The coating method is powder coated using an electrostatic coating gun or a tribostatic coating gun, which is a corona coating machine, and the base is baked for about 10 to 40 minutes in a temperature range of 130 to 170 ° C. to obtain a coating film.

Alternatively, the aqueous base may be coated, followed by powder coating to bake at 130 to 160 ° C. for 20 to 40 minutes to obtain a beautiful appearance. In particular, the base coat containing the water-soluble metallic pigment can obtain a more beautiful appearance than to apply a solvent-type coating to obtain an external effect and a beautiful appearance. After 10 minutes of stabilization of the water-soluble base and flash-off at 80 to 120 ° C for 10 minutes, and then powder coating and baking for 20 to 40 minutes at 130 to 160 ° C, a coating film having excellent physical properties as well as an excellent coating film can be obtained within a short time. You can get it.

When using the powder coating as in the present invention can be applied to the environment-friendly coating that can minimize the use of volatile organic compounds, which will be described in the case of solvent solvent and solvent clear coating on the water-soluble base, In case of coating powder clear on water soluble base and water soluble base, In case of coating powder clear on water soluble middle and water soluble base, In case of coating water clear and powder clear on water soluble medium and solvent base There is a case. However, the coating that can minimize the most volatile organic compounds is the case of coating the powder clear after coating the water-soluble base in the powder weight.

As described above, according to the present invention by using the powder coating as described above to obtain excellent physical properties by coating on the vehicle body medium and the top coating for the car body, in particular when the coating on the electrodeposition coating or the powder coating on the water-soluble or solvent base After paint is applied, the powder or solvent type clear has a beautiful appearance and excellent physical properties.

In the present invention, for example, after coating the solvent-based base and the solvent-type clear on the painted base, the powder coating system to obtain a beautiful appearance and excellent physical properties, and after coating the water-soluble base on the coated base, the exterior after coating the solvent-type clear Powder coating system to obtain excellent physical properties, water-soluble base on painted base, and then powder clear to be applied, powder coating system to obtain beautiful appearance and excellent physical properties, and solvent type coating on painted base. Powder coating system to obtain excellent appearance and excellent physical properties, solvent-based base on painted base, powder coating clear, and powder coating system to get beautiful appearance and excellent physical properties, water-soluble base on painted base After painting the powder coating clear, excellent appearance and excellent physical Powder coating system to obtain the properties, the powder coating system applying the powder coating composition of the present invention after coating the solvent-type intermediate on the coating, the powder coating system applying the powder coating composition of the present invention after coating the water-soluble intermediate on the coating Or the like for powder coating systems.

In the present invention, a solvent-based base and a powder clear are applied to the specimen on which the powder coating film is formed. For example, dry on dry or water-soluble base and powder clearcoat are dry on wet or water-soluble base and powder. The coating film obtained by coating the clear coat by dry on dry and baking for 20 to 40 minutes at 130 to 170 ° C satisfies the beautiful appearance and physical properties applied to the vehicle body.

Alternatively, dry on dry or water soluble base and powder clearcoat on specimens with water soluble or solvent intermediate coatings are dried on wet or water soluble base and powder clear coat. The final coating obtained by coating dry on dry for 15 to 40 minutes at 130 to 170 ° C satisfies the beautiful appearance and physical properties applied to the vehicle body.

Powder coatings used in the present invention are classified into various types depending on the type of resin and the curing agent type constituting the coating. According to this paint composition, epoxy powder coating, epoxy-polyester powder coating, polyester powder coating (powder coating using a curing agent such as triisocyanate hydrate, hydroxyalkylamide, curing agent using isocyanate), acrylic type Powder coatings (glycidyl methacrylate functional groups and powders that react with polyhydric basic acids, carboxyl functional groups and oxirane groups and powders react with isocyanates while reacting with isocyanates) It is classified and used selectively according to the intended use.

In such powder coatings, epoxy powder coatings and epoxy polyester powder coatings have good physical properties or durability, but have poor weather resistance and yellowing. Polyester powder coating has good physical properties, but its appearance is somewhat poor and weather resistance is good, but weather resistance is not satisfactory. Acrylic powder coatings are not the best physical properties and water resistance, but weatherability and appearance is the best type.

Although each paint type has advantages and disadvantages, in the present invention, it is selectively used according to required physical properties, and selection of an appropriate paint is characterized by obtaining optimum physical properties satisfying the required physical properties of the vehicle body coating film.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by Examples.

The following is an embodiment of the vehicle powder coating according to the resin and the curing agent for the paint production in the present invention, it is not limited to the vehicle powder coating composition. In addition, a paint was prepared using the method for producing a powder coating resin and the resin used in the present invention, and the physical properties thereof were evaluated. For information on manufacturing resin for powder coating, refer to Korean Patent Publication Nos. 91-11970, 95-12764, 95-7994, 94-3867, 95-12768 and 96-2956. Nos. 91-6389 and 90-5396, which were used in the present invention, were prepared according to the production methods for producing resins for powder coating, which show their respective uses.

Method for producing acidic polyester resin having carboxyl group at the end 1.

Preparation Example 1-1

1,050 parts by weight of terephthalic acid, 450 parts by weight of isophthalic acid, 80 parts by weight of adipic acid, 1,040 parts by weight of neopentyl glycol, 26 parts by weight of trimethylolpropane, 136 parts by weight of HPHP, 50 parts by weight of ethylene glycol, 2.5 parts by weight of dibutyltin oxide After addition and heating up to 230 ℃ reaction acidic polyester resin having a carboxyl group at the terminal was prepared using 300 parts by weight of trimellitic anhydride, 132 parts by weight of cyclohexanedicarboxylic acid, the number average molecular weight of the resin is 2,600 and the acid value is 60 Mm KOH / g and softening point is 116 ° C.

Preparation Example 1-2

1,500 parts by weight of terephthalic acid, 148 parts by weight of adipic acid, 1,092 parts by weight of neopentyl glycol, and 120 parts by weight of 1,6-hexanediol were used as a catalyst and 2.5 parts by weight of dibutyltin oxide were prepared to prepare a prepolymer. After the acidic polyester resin having a carboxyl group at the end by using 300 parts by weight of trimellitic anhydride, 140 parts by weight of succinic acid, the number average molecular weight of the resin is 300, the acid value is 76 mm KOH / g and the softening point is 117 ℃.

As the curing agent for the resin produced below, hydroxyalkylamides and oxiranes or other ester or polyacrylic curing agents are used. As the curing agent to be used, powder coating is prepared using commercially available curing agents such as PT810 (CIBA-GEIGY), PT910 (CIBA-GEIGY), PRIMID XL 552 (ROHM HAAS), POWDERLINK 1174 (CYNAMID).

Preparation Example 1-3

1,350 parts by weight of terephthalic acid, 120 parts by weight of isophthalic acid, 50 parts by weight of adipic acid, 1,300 parts by weight of neopentyl glycol, and 310 parts by weight of ethylene glycol. After preparing the prepolymer, an acidic polyester resin leaving a carboxyl group at the terminal was prepared using 120 parts by weight of trimellitic anhydride and 65 parts by weight of isophthalic acid. The acid value thereof is 29 mg KOH / g and a softening point of 120 ° C.

Preparation Example 1-4

1.8 parts by weight of zinc acetate was added to 1,400 parts by weight of dimethyl terephthalic acid, 600 parts by weight of diethylene glycol, and 960 parts by weight of neopentyl glycol, and reacted while removing methanol to 210 ° C. Then, 150 parts by weight of isophthalic acid and 50 parts of adipic acid were added thereto. The reaction was carried out at a temperature of up to 230 ° C. to react with 155 parts by weight of trimellitic anhydride and 110 parts by weight of adipic acid. The acidic poly acid had a number average molecular weight of 3,500 and an acid value of 42 mg KOH / g and a softening point of 119 ° C. An ester resin was prepared.

Preparation Example 1-5

15 parts by weight of butyltin oxide diluted in a mixture of 966 parts by weight of dodecanecandioic acid and 236 parts by weight of hexanediol are added for 30 minutes, and then reacted at 150 ° C. for 1 hour and then refluxed for 3 hours. After the reaction, the reaction residue is removed in vacuo to give a white solid.

It is also prepared by reacting with alcohols such as hexanediol, butanediol and diethylene glycol using sebacic acid and undecanedioic acid.

Method for producing polyester resin containing anhydride functional groups at the end 2

Preparation Example 2-1

3,105 parts by weight of dodecanedioic acid and 918 parts by weight of acetic anhydride are reacted under nitrogen air at 125 ° C. for 4 hours and then refluxed at 150 ° C. for 1 hour. The reaction residue is removed in vacuo to yield a pale white solid.

It is also prepared by reacting sebacic acid and undecanedioic acid with acetic anhydride.

Manufacturing method 3 of the polyester resin which has a hydroxyl group at the terminal

Preparation Example 3-1

After reacting 436 parts by weight of neopentyl glycol, 552 parts by weight of terephthalic acid and 1 part by weight of Huxquet 4201 to 230 ° C, 117 parts by weight of isophthalic acid, 25 parts by weight of sebacic acid and 28 parts by weight of trimethylolpropane were reacted with hydride. Solid materials having a carboxyl group of 35 ± 5, an acid value of 2.2 and a melting point of 110 to 115 ° C were obtained.

Method for producing acrylic resin having oxirane functional groups at the end 4

Preparation Example 4-1

105.6 parts by weight of butyl acrylate, 96 parts by weight of ethyl acrylate, 124.8 parts by weight of glycidyl acrylate, 268.8 parts by weight of methyl acrylate, 364.8 parts by weight of styrene, 19.2 parts by weight of azobisisobutyronitrile to 140 After reacting and refluxing for 1 hour, 2.5 parts by weight of azobisisonitrile was added, followed by vacuum distillation, and the solvent was removed to obtain a solid.

Method for producing acrylic resin having hydroxyl group at terminal 5

Preparation Example 5-1

253.5 parts by weight of butyl acrylate, 96 parts by weight of 2-hydroxyethyl methacrylate, 9.8 parts by weight of methacrylic acid, 295.3 parts by weight of methyl methacrylate, 305.2 parts by weight of styrene, 19.2 parts by weight of azobisisobutyronitrile The reaction mixture was raised to 140 ° C., reacted to reflux for 1 hour, and then 2.5 parts by weight of azobisisobutyronitrile was added to reflux for 1 hour, followed by vacuum distillation to remove the solvent to obtain a solid.

Method for producing acrylic resin containing carboxyl group at the end 6

Preparation Example 6-1

400 parts by weight of methyl methacrylate, 100 parts by weight of acrylic acid, 50 parts by weight of acrylamide, 300 parts by weight of 2-ethylhexyl acrylate, 150 parts by weight of styrene, and 10 parts by weight of t-butyl peroxyoctane as initiator. 3 parts by weight of zero n-dodecyl mercaptan is mixed and the solvent is reacted by dropwise reaction with 1,200 parts by weight of n-butanol over 3 hours to reflux for 2 hours, and 0.5 parts by weight of benzoyl peroxide is added to 25 parts by weight of toluene. After the reaction for 2 hours, 0.5 parts by weight of benzoyl peroxide was added to 25 parts by weight of toluene, and then reacted for 3 hours, and then the solvent was removed under vacuum to obtain an acrylic resin. The acid value of the obtained resin is 65 mg KOH / g and the number average molecular weight is 1,200.

Example 1 Preparation of Powder Coating Primer Surfacer (Medium)

Powder coating resins, curing agents, additives and pigments are pre-mixed uniformly in Henshell Mixer for 2 to 6 minutes and then uniformly dispersed using PLK 46L (BUSS Co., Ltd.) melt mixer in the temperature range of about 90 ~ 140 ℃ Let's do it. This dispersion process may be repeated two or more times. The mixture is cooled in a chiller roller, and then the mixture is ground using a sample mill (Sample Mill, manufactured by Fugi Powdal) and manufactured through about 200 mesh sieves. Alternatively, ACM 2L (Test Mass Mill, Hoso Kawasaki) was used to prepare a powder coating having an average particle size of 15 to 25 μm. In addition, a classifier [Turbo Classifier, TC-III S and TC-III C (Nishin Engine Earring Company) or DS Classifier, DS-2 S and DS-2 C (Nippon Pneumatic Company)] It was prepared using to control the size and particle size distribution of the desired particles.

The powder coating was prepared by using Onoda electrostatic coating gun (model name: GX 108) or a corrugated electrostatic coating gun (model name: GX 304), which is a corona coating machine, on a specimen coated with zinc phosphate coating on a cold rolled iron plate. Powder coated body was baked in a temperature range of 150 to 200 ° C. for about 10 to 40 minutes to obtain a coating film.

The coated film is coated with a solvent-based base and a solvent-based clear coat, a water-soluble base and a solvent-clear clear coat, a solvent-based base and a powder clear coat, or a water-soluble base and a powder clear coat. Bake for a minute to get a final coating.

Examples 2 to 22: powder coating intermediate production

Powder coating intermediate was prepared in the same manner as in Example 1 to Table 1 to Table 3, respectively.

Examples 22 to 24 Preparation of Powder Coating Clear Coat

The powder coating resin, the curing agent, and the additives are uniformly premixed in a Henshell Mixer for 2 to 6 minutes and then uniformly dispersed using a PLK 46L (BUSS) melt mixer at a temperature range of about 60 to 100 ° C. This dispersion process may be repeated two or more times. The mixture is cooled in a chiller roller, and then the mixture is ground using a sample mill (Sample Mill, manufactured by Fugi Powdal) and manufactured through about 200 mesh sieves. Alternatively, ACM 2L (Test Mass Mill, Hoso Kawasaki) was used to prepare a powder coating having an average particle size of 8 to 20 μm. In addition, in order to manufacture finely divided powder coating, a commonly used micron separator or a classifier [Turbo Classifier, TC-III S and TC-III C (Nisshin Engine Earring Co., Ltd.) or DS Classifier, DS-2 S and DS- 2C (Nippon Pneumatic Co., Ltd.)] to adjust the size and particle size distribution of the desired particles.

The powder coating was prepared by coating the powder coating primer surfacer on the specimen coated with zinc phosphate coating on the cold rolled iron plate and coated with cation electrodeposition, and then forming a coating film.The solvent-based base and the water-soluble base were dried on wet or 2 coats 2 baking method. Powder coating is applied. The coating method is powder coated using Onoda electrostatic coating gun (model name: GX 108) or friction electrostatic coating gun (model name: GX 304), which is a corona coating machine, and the material is baked for about 10 to 40 minutes at a temperature range of 130 to 170 ° C. To obtain a coating film.

The coating film finally obtained in the Example of this invention was tested by the following method, and the final physical property was confirmed.

1) Appearance

Gloss: Measured using a 20 ° / 40 ° glossmeter.

Image Sharpness: Image sharpness was measured using PGD # 4, which is the device model name (vertical / horizontal image sharpness).

2) impact resistance test

Measure using a DuPont impact tester.

Use 500g weight and 1/2 curved surface.

3) acid resistance test

Acid resistance test is conducted by spot test, and the chemical resistance of the coating film is measured by dropping 0.625ml of 10% sulfuric acid and measuring the degree of color fading or change at each temperature (50, 60, 70, 80 ℃) using a gradient oven. Evaluate.

The evaluation is as follows according to the degree of discoloration.

◎: Good state without traces in the coating film

○: state in which fine traces remain on the coating film

(Triangle | delta): The state which trace remains slightly in a coating film

X: state in which the coating film is corroded

4) hardness test

Test the strength of the coating using a Mitsubishi Uni pencil.

5) yellowing test

The yellowing degree with the paint baked one time after baking for 30 minutes twice at each paint baking temperature is measured.

6) water resistance test

The coated specimen was immersed in a water bath at 40 ° C. for 240 hours and left for one hour at room temperature to check its appearance.

There should be no discoloration of the coating, such as blisters or swelling.

7) Solvent resistance test

The gauze cloth soaked in xylene should be left unchanged for 10 minutes in the final coating.

8) oil resistance test

Immerse in engine oil for one hour and measure the degree of change in coating.

Measured with 65% relative humidity and 20 ℃.

9) Isolability Test

Under normal conditions, the specimen is soaked in gasoline for 1 hour to measure the degree of change in the coating.

10) Cold resistance chipping resistance

After leaving the painted specimens at -40 ° C for 3 hours, 50 g of chipping stones were used to collide at a pressure of 4 kg / cm 2.

Measure the size and number of impacts on the surface of 6 × 7 cm 2.

11) Weather resistance

Measure with a xenon arc weather meter.

At CAM 180 1000 hrs, gloss retention is over 80%.

division Example One 2 3 4 5 6 7 8 Preparation Example 1-1 - 60 55 50 - - - - Preparation Example 1-2 - - - - 55 50 50 50 Preparation Example 1-5 - - 7 - - 7 7 - Preparation Example 2-1 - - - - - - - 5 B-1530 ¹⁾ - - - - - - 5 - KD-013 ²⁾ 45 - - - - - 50 - KD-012 ³⁾ - 40 40 45 45 45 - 45 N 8025 ⁴⁾ 55 - - 5 - - - 5 Benzoin ⁵⁾ 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Casamid 783 ⁶⁾ 3 - - - - - - - Fascat 4352 ⁷⁾ - 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Irganox1076 ⁸⁾ 0.5 0.5 0.5 0.5 0.5 0.5 - - Irganox1010 ⁹⁾ - - - - - - 0.5 0.5 PV-5 ¹⁰⁾ 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 TiO ₂ 40 40 40 40 40 40 40 40 Carbon black 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Cy-blue 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 CaCO ₃ 10 10 10 10 10 10 10 10 SurfynolP200 ¹¹⁾ - 0.3 0.3 0.3 0.3 0.3 0.3 0.3

* Note:

1) B-1530: Huls isocyanurate curing agent with caprolactam blocked

2) N8030: Trade name of epoxy resin produced by Korea Chemical (Epoxy equivalent of 750 ~ 870)

3) N8020: Trade name of epoxy resin produced by Korea Chemical (Epoxy equivalent 600 ~ 700)

4) N 8025: Trade name of epoxy resin produced by Korea Chemical (CTBN substituted epoxy resin with epoxy equivalent 990)

5) Benzoin: Outgassing agent (BASF company)

6) B-31: Huls curing catalyst.

7) Fascat 4352: Trade name of elF atochem.

Irganox 1076: Antioxidant from Ciba-Geigy

9) Irganox 1010: Antioxidant from Ciba-Geigy

10) PV-5: Polyacrylate leveling agent of Worlee.

11) Surfynol 104: air releasing agent from Air Products and Chemicals Inc.

division Example 9 10 11 12 13 14 15 16 Preparation Example 1-3 93 90 93 - - - - - Preparation Example 1-4 - - - 95 90 95 - - Preparation Example 1-5 - 5 - - 5 - - 5 Preparation Example 2-1 - - 5 - - - 3 - Preparation Example 3-1 - - - - - - 80 80 PT 810 ¹²⁾ 7 7 7 - - - - - XL 552 ¹³⁾ - - - 5 5 5 - - B-1530 - - - - - 5 20 - BF-1540 ¹⁴⁾ - - - - - - - 20 N 8025 - 5 - - 5 - - 4 Enzoin 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Fascat 4352 - - - - 0.2 - - - DBTDL - - - - - - 0.3 0.3 Irganox1076 0.5 - 0.5 0.5 0.5 - - 0.5 Irganox1010 - 1.0 - - - 1,0 0.5 0.5 PV-5 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 TiO ₂ 30 40 30 30 40 40 30 40 Carbon black 0.2 0.15 0.2 0.2 0.2 0.2 0.2 0.2 Cy-blue 0.1 0.08 0.1 0.1 0.1 0.1 0.1 0.1 Surfynol P200 - 0.3 - 0.5 0.5 0.5 0.3 0.3 Tinuvin 144 ¹⁵⁾ 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Tinuvin 900 ¹⁶⁾ 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0

* Note:

12) PT 810: Triglycidyl isocyanurate curing agent from Ciba-Geigy.

13) XL 552: Trade name for the curing agent of hydroxyl alkylamides produced by ROHM HASS.

14) BF-1540: Unblocked Huls Hardener

15) Tinuvin 144: UV-HALS product of Ciba-Geigy.

16) Tinuvin 900: UV absorber of Ciba-Grigy.

division Example 17 18 19 20 21 22 23 24 Preparation Example 4-1 79 79 - - - - - - Preparation Example 5-1 - - 85 85 85 - - - Preparation Example 6-1 - - - - - 93 - - Preparation Example 1-5 - - - - 4 - - - Preparation Example 2-1 - - - - 3 - - - PD 3402 ¹⁷⁾ - - - - - - 78.5 71 LS 2125 ¹⁸⁾ - - - - - - - 29 DDDA ¹⁹⁾ 21 21 - - - - 21.5 - PT 810 - - - - - 7 - - B-1530 - - 15 15 - - - - N 8025 4 - - 4 4 - - - Enzoin 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Fascat 4352 - - - - 0.15 - - - Tin-Octate - - - - - - 0.2 0.3 DBTDL - - 0.3 0.3 - - - - Irganox1076 0.5 0.5 0.5 0.5 0.5 - - - PV-5 1.0 1.0 1.0 1.0 1.0 1.0 - - BYK-361 ²⁰⁾ - - - - - - 1.0 - EX 570 ²¹⁾ - - - - - - - 1.0 TiO ₂ 30 30 30 30 40 40 - - Carbon black 0.2 0.15 0.2 0.2 0.2 0.2 - - Cy-blue 0.1 0.08 0.1 0.1 0.1 0.1 - - Surfynol P200 - 0.3 - 0.5 0.5 0.3 - - Tinuvin 144 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Tinuvin 900 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0

* Note:

17) PD 3402: Acrylic resin for powder coating of glycidyl methacrylate type produced by Samjeong Co., Ltd.

18) LS 2125: A curing agent of the polycarboxylic acid type sold by Bayer.

19) DDDA: Aromatic carboxylic acid sold by Dupont.

20) BYK 361: A polyacrylate leveling agent commercially available from BK Kay.

21) EX 570: Polyacrylate leveling agent sold by Troy Chemicals.

division Example Remarks One 2 3 4 5 6 7 8 Polish 90 94 95 88 90 91 92 88 60 ° Impact resistance (cm) 40 50 45 50 50 45 50 50 1 kg Flexibility ○ ○ ○ ○ ○ ○ ○ ○ Ericsson Exam 8 7 6 7 7 6 7 7 Mm Hardness test H HB H 2H H HB 2H H Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Chipping resistance ◎ ○ ○ ◎ ○ ○ ○ ◎ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Oil resistance ○ ○ ○ ○ ○ ○ ○ ○

division Example Remarks 9 10 11 12 13 14 15 16 Polish 91 86 90 89 90 92 93 90 60 ° Impact resistance (cm) 50 45 45 50 40 50 40 50 1 kg Flexibility ○ ○ ○ ○ ○ ○ ○ ○ Ericsson Exam 7 6 6 7 5 7 5 7 Hardness test H 2H H HB HB H HB HB Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Chipping resistance ○ ◎ ○ △ △ ○ ○ ◎ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Oil resistance ○ ○ ○ ○ ○ ○ ○ ○

division Example Remarks 17 18 19 20 21 22 23 24 Polish 91 90 92 92 91 94 96 95 60 ° Impact resistance 40 40 40 35 40 45 50 50 500 g Flexibility ○ ○ ○ ○ ○ ○ ○ ○ 3/16 Ericsson Exam 5 5 5 4 5 6 6 6 Mm Hardness test H B HB HB B HB HB HB Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Chipping resistance ○ △ ○ △ △ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Oil resistance ○ ○ ○ ○ ○ ○ ○ ○

Experimental Examples 1 to 88

Coating systems for obtaining maximum physical properties while minimizing the amount of volatile organic compounds for each coating system are divided into four types shown in Table 5 below.

division TYPE 1 TYPE 2 TYPE 3 TYPE 4 Top Coat Yongjeojang Yongjeojang Powder Coating Powder Coating BASE COAT Yongjeojang Aqueous coating Yongjeojang Aqueous coating PRIMER SURFACER Powder Coating Powder Coating Powder Coating Powder Coating UNDO COAT Electrodeposition coating Electrodeposition coating Electrodeposition coating Electrodeposition coating

In each system, powder coating, solvent coating and aqueous coating are applied to the substrate which is subjected to cationic electrodeposition on the pretreated base of zinc phosphate coating on 0.8T and CR steel sheets.

In addition, the powder coating is applied directly to the place where the zinc phosphate coating is pre-germinated to obtain the same physical properties even in the final coating. In this method, a dry-on-wet or dry-on-dry coating system was also applicable to powder coating on electrodeposition coating. However, in the present invention, the coating is formed after the coating film is formed using a dry-on-dry coating system.

When coating the top coat, the base coat and the top coat were coated for each coating system by wet or dry like dry-dry method and tested for their physical properties. The coating system of the present invention was performed in the present invention, the wet-on-wet coating. When the solvent is applied on the aqueous coating, the wet-on-dry or dry-on-dry coating is applied. In the case of powder coating in the solvent coating system and powder coating in the aqueous coating, dry-on-dry coating was applied.

Comparing the coating method of the present invention with the conventional coating method is shown in the following Table 6.

Coating composition Film thickness Conventional coating method How to paint How to paint Remarks Top Coat 30 to 45 μm Yongjeojang Yongjeojang Powder Coating BASE COAT 10 to 20 μm Yongjeojang Solvent / Aqueous Coating Aqueous coating Medium (PRIMERSURFACER) 30 to 45 μm Yongjeojang Solvent / Powder Coating Powder Coating UNDO COAT 15 to 30 μm Electrodeposition coating Electrodeposition coating Electrodeposition coating Volatile Solvent 102 21-45 21 g / ㎡

division Example 1 Example 2 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example One 2 3 4 5 6 7 8 Polish 81 82 83 83 83 87 85 88 20 ° Image clarity ○ △ ○ ○ ○ △ ○ ○ Impact resistance 50 50 50 50 40 45 50 50 500 g Water resistance ○ △ ○ ○ ○ ○ ○ ○ Solvent resistance ○ △ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance ◎ ○ ○ ◎ ○ ○ ○ ○ Weather resistance △ △ △ △ ○ ○ ○ ○

division Example 3 Example 4 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 9 10 11 12 13 14 15 16 Polish 82 86 84 87 81 82 83 80 20 ° Image clarity ○ ○ △ ○ △ △ ○ ○ Impact resistance 45 35 40 45 45 40 45 500 500 g Water resistance ○ ○ △ ○ ○ ○ ○ ○ Solvent resistance ○ △ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance △ ○ ○ △ ○ △ ○ ○ Weather resistance △ ○ ○ ○ ○ △ ○ ○

division Example 5 Example 6 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 17 18 19 20 21 22 23 24 Polish 81 75 82 80 78 81 82 81 20 ° Image clarity ○ ○ △ ○ ○ ○ ○ ○ Impact resistance 45 45 45 45 45 40 40 45 500 g Water resistance ○ ○ △ ○ ○ ○ ○ ○ Solvent resistance ○ ○ △ ○ ○ ○ ○ ○ Acid resistance ○ ○ △ ○ ○ ○ △ ○ 60 ℃ Chipping resistance △ ○ △ ○ ○ ○ △ ○ Weather resistance ○ ○ ○ ○ ○ ○ ○ ○

division Example 7 Example 8 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 25 26 27 28 29 30 31 32 Polish 81 83 82 88 81 78 82 84 20 ° Image clarity ○ △ △ ○ △ ○ △ ○ Impact resistance 50 45 45 50 50 45 40 50 Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance △ ○ △ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance ○ △ ○ ○ ○ ○ ○ ◎ Weather resistance ○ ○ ○ ○ ○ △ ○ ○

division Example 9 Example 10 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 33 34 35 36 37 38 39 40 Polish 82 76 84 81 80 77 81 84 20 ° Image clarity △ △ △ ○ △ △ ○ ○ Impact resistance 50 50 50 50 50 50 50 50 Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance △ △ △ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance ○ △ ○ ○ ○ ○ ○ ○ Weather resistance ○ ○ △ ○ ○ ○ ○ ○

division Example 11 Example 12 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 41 42 43 44 45 46 47 48 Polish 79 74 80 81 74 78 76 79 20 ° Image clarity △ △ △ △ △ △ △ △ Impact resistance 50 50 50 50 40 45 40 45 Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Oil resistance ○ △ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ △ △ △ ○ 60 ℃ Chipping resistance ○ ○ ○ ○ ○ ○ ○ ◎ Weather resistance ○ ○ ○ ○ ○ ○ △ ○

division Example 13 Example 14 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 49 50 51 52 53 54 55 56 Polish 78 79 79 81 80 81 82 85 20 ° Image clarity △ △ △ △ ○ △ △ ○ Impact resistance 40 40 40 45 50 50 50 50 500 g Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance △ △ △ △ △ △ ○ ○ 60 ℃ Chipping resistance △ △ △ △ △ ○ △ ○ Weather resistance △ △ △ ○ △ ○ △ ○

division Example 15 Example 16 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 57 58 59 60 61 62 63 64 Polish 82 83 81 85 81 84 83 86 20 ° Image clarity ○ ○ ○ ○ ○ ○ ○ ○ Impact resistance 45 45 40 50 50 45 50 50 500 g Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance △ △ △ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance △ △ ○ ○ ○ ○ ○ ◎ Weather resistance △ △ ○ ○ ○ ○ ○ ○

division Example 17 Example 18 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 65 66 67 68 69 70 71 72 Polish 85 86 84 89 86 82 85 88 20 ° Image clarity ○ ○ ○ ○ ○ ○ ○ ○ Impact resistance 30 40 40 45 40 35 40 45 500 g Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ △ △ ○ ○ △ △ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance × × × △ × × × × Weather resistance ○ ○ ○ ○ ○ ○ ○ ○

division Example 19 Example 20 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 73 74 75 76 77 78 79 80 Polish 82 81 83 84 81 83 80 82 20 ° Image clarity △ △ △ ○ △ △ ○ ○ Impact resistance 45 40 45 45 45 40 50 50 500 g Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance ○ △ ○ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance ○ × ○ ○ ○ △ △ ○ Weather resistance ○ △ ○ ○ ○ △ ○ ○

division Example 21 Example 22 Remarks TYPE One 2 3 4 One 2 3 4 Experimental Example 81 82 83 84 85 86 87 88 Polish 85 86 85 88 83 84 81 84 20 ° Image clarity ○ ○ ○ ○ △ △ △ △ Impact resistance 40 45 45 40 45 45 45 45 Water resistance ○ ○ ○ ○ ○ ○ ○ ○ Solvent resistance ○ ○ ○ ○ ○ ○ ○ ○ Acid resistance ○ ○ ○ ○ ○ ○ ○ ○ 60 ℃ Chipping resistance ○ △ △ ○ ○ ○ ○ ○ Weather resistance ○ △ ○ ○ ○ ○ ○ ○

As described above, the powder coating composition of the present invention has excellent chip resistance and impact resistance, as well as smoothness and sharpness, and has a beautiful appearance, and can be usefully applied to automobile body parts and parts coatings having low volatile organic compound emission. .

Claims (25)

In a powder coating composition mainly composed of thermosetting resins such as epoxy resins and polyester resins, (1) Epoxy resins having two or more oxirane groups as base materials, polyester resins having two or more carboxyl end groups, polyester resins having two or more hydroxyl groups, two or At least one thermosetting resin selected from an acrylic resin having more than one hydroxyl functional group, an acrylic resin having two or more carboxyl functional groups, and an acrylic resin having a GMA (glycidyl methacrylate) functional group; (2) at least one curing agent selected from an oxirane epoxy curing agent, an isocyanate curing agent having an isoprene diisocyanate blocking agent, an isocyanurate curing agent and a polyvalent basic acid; (3) additives including catalysts, polyacrylate-based leveling agents, wetting agents, dispersants, antioxidants, and light stabilizers; (4) organic and inorganic pigments; And (5) polycarboxylic acids and acid anhydrides Powder coating composition characterized in that it has. The powder coating composition according to claim 1, wherein the epoxy resin comprising two or more oxirane groups has an epoxy equivalent of 450 to 2,000 equivalents and a softening point in the range of 60 to 130 ° C. The powder coating composition according to claim 1, wherein the polyester resin having two or more carboxyl groups has an acid value of 20 to 85 and a Tg of 30 to 85 ° C. The powder coating composition of claim 1, wherein the polyester resin having two or more hydroxyl groups has a hydroxyl group of 30 to 120 and a Tg of 30 to 85 ° C. The powder coating composition according to claim 1, wherein the acrylic resin having two or more carboxyl groups has an acid value of 20 to 50 and a Tg of 30 to 85 ° C. The powder coating composition according to claim 1, wherein the acrylic resin having two or more hydroxyl groups has a hydroxyl group of 30 to 120 and a Tg of 30 to 85 ° C. The powder coating composition of claim 1, wherein the acrylic resin having two or more glycidyl methacrylate functional groups has an equivalent weight of 300 to 800 and a Tg of 30 to 80 ° C. The powder coating composition of claim 1, wherein the epoxy resin having two or more oxirane functional groups has an equivalent in the range of 350 to 2,000 and a Tg in the range of 20 to 90 ° C. The polyisocyanate compound according to claim 1, wherein the polyisocyanate compound is a solid compound having a melting point of 50 to 110 ° C, and is a block polyisocyanate compound obtained by the reaction of a blocking agent selected from phenol, caprolactam and alcohol, or isoprene diisocyanate and hexamethylene diisocyanate. And a powdered polyisocyanate compound selected from hydroxylated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolyene diisocyanate, xylene diisocyanate, tolyene diisocyanate. The method of claim 1, wherein the saturated unsaturated dibasic acid having two or more carbon atoms is succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, undecanoic acid, brassic acid, citraconic acid, eco Powder coating composition comprising noic acid, or dodecanoic acid. The catalyst of claim 1, wherein the catalyst is tetrabutyl ammonium chloride, bromide or iodide, ethyltri phenylphosphonium, acetate, octotic cationic acid, triphenylphosphine, 2-methylimidazole, 2-C _11. Powder coating composition comprising 0.1 to 3% by weight based on the total coating composition of -imidazole, 2-C ₁₇ -imidazole and dibutyltin laurate. The coating composition of claim 1, wherein the coating composition comprises polylauryl acrylate, polybutyl acrylate, poly (2-ethylhexyl) acrylate, poly (ethyl-2-ethylhexyl) acrylate, polylauryl methacrylate and Powder coating composition, characterized in that it comprises a flow control agent selected from polyisodecyl methacrylate. According to claim 1, wherein the inorganic pigment is titanium oxide, carbon black, black iron oxide, red iron oxide, zinc sulfide, lithopone, barium sulfate, aluminum hydroxide, cadmium yellow, lead sulfide, lead lead, alumina white, calcium carbonate, Selected from silicon oxide and silicon carbonate; Organic pigments include azo-type pigments, benzoimidazole pigments, phthalocyanine pigments, thioindigo pigments, anthraquinone pigments, flavatron pigments, indanthrene pigments, anthrapyridine pigments, pyrantrone pigments, isoinflinone pigments, Powder coating composition, characterized in that it is selected from a pinylene pigment, a pyridone pigment and a quinna credon pigment. 2. The powder coating composition of claim 1, wherein the polycarboxylic acid and acid anhydride comprise saturated or unsaturated aromatic and aliphatic basic acids having two or more carbon atoms. 15. The polycarboxylic acid and acid anhydride according to claim 1 or 14, wherein the polycarboxylic acid and acid anhydride have at least one or more acid anhydrides in a solid phase at room temperature and have a melting point of 40 to 150 DEG C as phthalic anhydride and paracrorophthalic acid. Anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, tetrabromophthalic anhydride, cyclohexane 1,2-dicarboxy anhydride, cyclopentane-1,2-dicarboxyl anhydride, dodecyl succinic anhydride, succinic anhydride, A powder coating composition comprising one selected from maleic anhydride, methyl succinic anhydride, azelaic anhydride, polyceva anhydride, polydodecanenoic anhydride and polyenoic acid anhydride. A method of using a powder coating composition characterized by coating a zinc phosphate coating on a cold roll steel sheet and then applying the powder coating composition according to claim 1 to the cationic electrodeposited coating by electrostatic coating. The method of using a powder coating composition according to claim 16, wherein the powder coating composition is coated with a solvent-based base and a solvent clear. 17. The method of using a powder coating composition according to claim 16, wherein the powder coating composition is coated with a solvent-based clear after coating the water-soluble base on the coated base. The method of using a powder coating composition according to claim 16, wherein the powder coating composition is coated after the water-soluble base is coated on the base coated with the powder coating composition. 17. The method of using a powder coating composition according to claim 16, wherein the powder coating composition is coated with a solvent-based coating on a base coated with the powder coating composition. 17. The method of using a powder coating composition according to claim 16, wherein the powder coating clear is coated after the solvent-based base is coated on the base coated with the powder coating composition. The method of using a powder coating composition according to claim 16, wherein the powder coating composition is coated after the water-soluble base is coated on the base coated with the powder coating composition. 17. The method of claim 16, wherein the powder coating composition is coated with the solvent-based base and the solvent-type clear coat wet on wet (wet on wet), the water-soluble base and solvent-type clear coat dry on wet (dry on wet) wet), solvent-based base and powder clearcoat are dried on wet or coated with water-soluble base and powder clearcoat by dry on wet and baked at 130-170 ℃ for 10-40 minutes. How to use the powder coating composition, characterized in that. 17. The method of claim 16, wherein the powder coating composition is applied after coating a solvent-based intermediate on the coating object. The method of claim 16, wherein the powder coating composition is applied after coating the water-soluble intermediate on the coating object.