KR20000046302A - Micorgel water-soluble paint composition containing acryl core-shell emulsification polymer - Google Patents

Abstract

PURPOSE: A water-soluble paint composition is provided which is contained a acryl core-shell emulsification polymer having excellent weather-resistance and impact-resistance. So chemical-resistance property of a conventional paint is enhanced, and sticking property, abrasion property, anticorrosive property and impact-resistance are enhanced. CONSTITUTION: A water-soluble paint composition comprises; 33-75wt% of microgel emulsion polymer; 15-25wt% of paints comprised colored paint, screening paint and anticorrosive paint; 6-12wt% of cosolvent; 0.2-2.0wt% of dispersant; 0.1-1wt% of a polysiloxanic acid wetting agent; 0.05-0.5wt% of a polysiloxanic acid antifoaming agent; 0.5-1.5wt% of an ionic acryl copolymer levelling agent; and 1-3wt% of thickener.

Description

Microgel Water Soluble Coating Composition Containing Acrylic Core Shell Emulsion Polymer

The present invention relates to a water-soluble coating composition prepared by introducing an acrylic core shell emulsion polymer having excellent weather resistance and impact resistance into a microgel resin composition. More specifically, the present invention relates to a microgel resin which provides rust resistance, water resistance, solvent resistance and fast drying property. Including the acrylic core shell emulsion polymer, pigments, extender pigments, rust preventive pigments, co-solvents, additives, etc. in the resin composition composed of the resin improves the chemical resistance properties of existing water-based paints, adhesion to metal and old film base material, abrasiveness, and The present invention relates to a water-soluble coating composition having improved rust resistance and impact resistance.

Recently, the issue of global environmental preservation, which is gaining global attention, has emerged as an important issue in the international community, and the regulations of each country have already been enacted and the degree of regulation is being strengthened. In addition, the recent rise of the green round represents the seriousness. Developed countries have developed and applied anti-pollution paints such as low solvent paints, waterborne paints, powder paints, and special hardening paints, and continue to expand their scope. In Korea, the regulation of paint manufacturing facilities and painting facilities will begin in earnest from 1999. Therefore, it is necessary to expand water-soluble paints to industrial use, automobile use, etc. from existing construction. However, when applying water-soluble resins for paints to paints in the past and the present, they are not only inferior to existing useful paints in water resistance, impact resistance, adhesion, abrasiveness, dryness, etc., but also target properties of oil paints in painting workability and appearance. Could not meet.

On the other hand, since emulsion polymers are water-based, there is no risk of fire and no harmful organic solvents are released, which is easy to handle, but there are many challenges in terms of transparency, gloss, corrosion resistance, solvent resistance, mechanical strength, etc. An organic solvent type resin is used. In recent years, the development of emulsion polymers of various types has been newly developed along with the improvement of defects of conventional emulsion polymers. One of them is the preparation of core / shell-type emulsions called abnormal structure particles, multilayer structure particles, and composite particle emulsions. Technology. In other words, the composition of the core and the shell may be differently formed by the multi-stage emulsion polymerization process, thereby reducing costs, improving mechanical properties, providing good appearance, and imparting breathability.

U.S. Patent No. 4,539,363 discloses a method for producing a sintered microgel emulsion polymer by synthesizing core / shell-type polymer fine particles using a crosslinked core, and then neutralizing the carboxyl group of the shell composition with an amine to swell the shell, and a top coat for automobiles containing the same. The composition is described. This composition has the advantages of excellent spray workability and flow resistance due to the plasticity viscosity behavior, and the particle inside is crosslinked, so it is less affected by the penetration of organic solvent during the subsequent clear coating process, but has a high temperature of 100 ° C. or higher. In the composition that cross-links the outside of the particles by the melamine-formaldehyde resin in the car repair paints, plastic paints, building paints, etc., which are dried or baked at a relatively low temperature cannot be used because of poor water resistance. The reason is that a large amount of low molecular weight emulsifier is used during the polymerization process to synthesize small particles around 100 nm, which provides a water penetration path.

British Patent No. 2,206,591 discloses a method of blending acrylic resins with water-dispersible resins which have been converted into aqueous phase through azeotropic distillation after preparation under solvent to compensate for the poor water resistance of the microgel emulsion polymer added as the main resin for automotive refinish paints. Suggesting. This method has various problems such as the complicated polymerization process of the water-dispersible resin to be blended and the compatibility of the microgel emulsion polymer with the water-dispersible resin.

In addition, Korean Patent No. 149696 discloses a method for drastically reducing the low molecular weight emulsifier of a core / shell emulsion polymer, that is, neutralizing a core emulsion containing a sufficient amount of carboxylic acid groups prepared by conventional emulsion polymerization. Neutralization is used to prepare "similar water soluble resins" which are used as polymer dispersants to stabilize the two stage shell emulsion without the addition of an external low molecular weight emulsifier. The latex morphology of the resulting latex should be reversed core / shell structure and control of the morphology is presented as a core technology.

The present invention proposes a two-step polymerization process to reduce the amount of emulsifier in the same method as in the Republic of Korea Patent No. 149696 without using the existing core / shell two-stage process in the synthesis of the microgel emulsion polymer. That is, in the first stage fine particle manufacturing step, the polymer is prepared by the conventional emulsion polymerization method, but the anionic reactive emulsifier is sufficiently used in the hydrophilic monomer composition or the carboxylic acid group is used so that phase reversal may occur during the subsequent two-step shell polymerization. A "similar water soluble resin" is prepared using a method of neutralization after sufficient inclusion of the monomers possessed. In the two-step shell polymerization, phase inversion occurs by using a hydrophobic monomer composition using a crosslinking monomer in the monomer composition. When the resin is used as the main resin of the water-based paint, it has the advantages of the paint using the existing microgel emulsion polymer as the main resin, and at the same time, the water resistance is enhanced and can be used as a paint for construction, automobile repair, and plastic. In addition, when the coating material is prepared in the form of crosslinking the outside of the microgel resin, crosslinking density is higher than that of the non-microgel, so that the stain resistance and the denseness of the coating film are improved.

Accordingly, an object of the present invention is to provide a microgel water-soluble coating composition containing an acrylic core shell emulsion polymer excellent in weatherability and impact resistance.

The composition of the present invention for achieving the above object is 33 to 75% by weight of a microgel emulsion having a reversed phase core / shell morphology, 4 to 8% by weight of an acrylic core / shell emulsion, coloring pigments, extender pigments and rust preventive pigments 15 to 25% by weight of pigment, 6 to 12% by weight of solvent, 0.2 to 2.0% by weight of dispersant, 0.1 to 1% by weight of polysiloxane wetting agent, 0.05 to 0.5% by weight of polysiloxane antifoaming agent, 0.5 to 0.5% of ionic acrylic copolymer leveling agent 1.5 wt% and 1-3 wt% of thickener.

Looking at the present invention in more detail as follows.

The present invention provides a method for preparing a microgel emulsion polymer comprising a core / shell type morphology inverted by a two-step emulsion polymerization method to improve physical properties such as water resistance, solvent resistance, and rust resistance of existing water-based paints, and to improve weatherability and impact resistance. The present invention relates to a method for preparing an acrylic core shell emulsion polymer and to a coating composition comprising the core shell and a microgel, and more particularly, to a core emulsion containing a sufficient amount of a carboxylic acid group prepared by a conventional emulsion polymerization method. To prepare a one-stage core emulsion using a method of neutralizing the reaction mixture or by including an anionic reactive emulsifier in the core monomer composition to form a copolymer, and as a polymer dispersant, a stable secondary without containing an external low molecular weight emulsifier. Method for preparing a cross-linked shell emulsion, and the microgel as a main resin, internal crosslinked The water-free and alkali resistance, rust resistance, adhesion, weather resistance, impact resistance, etc. of the paint dry coating film are improved by containing an emulsion polymer having a particle size of 200 to 400 nanometers completely encapsulated in a solid shell having a Tg of 80 ° C. or more in a hard shell. It is related with the coating composition which gives a beautiful appearance.

Lee and Rudin report Polymer Latexes chap. 15, "Control of Core-Shell Latex Morphology", ACS symp. ser. 492, 1992, mentions the various conditions under which core / shell, reversed-phase core / shells are produced. That is, the core / shell structure can be achieved by configuring the core component and the shell component in hydrophilicity, hydrophobicity or polarity, and nonpolarity, respectively, and when the shell composition is composed of a fraction larger than the core composition, when the core particle size is large, This can be advantageously achieved when the core particles are crosslinked at high fractions. Reversed-phase core / shell structures are usually formed in the opposite direction of these conditions.

The microgel emulsion polymer of the present invention is prepared by a two step emulsion polymerization method. That is, 10 to 50 parts by weight of a monomer containing a carboxylic acid group in a molecule, 50 to 90 parts by weight of an uncrosslinked monomer containing one olefin in a molecule, and optionally two or more in the molecule relative to 100 parts by weight of the core monomer composition A cross-linking monomer containing an olefin and / or an anionic reactive emulsifier is added and reacted to prepare a core emulsion polymer, and 0.5 to 1.2 equivalents of a neutralizing agent is added to 1 equivalent of the carboxylic acid of the core emulsion polymer. Preparing a first step; And 88 to 99.9 parts by weight of a non-crosslinkable monomer containing one olefin in a molecule, and 0.1 to 12 parts by weight of a crosslinkable monomer containing two or more olefins in a molecule, based on 100 parts by weight of the shell monomer composition. A second step of manufacturing is included. Emulsion polymerization herein refers to a process that requires water in monomers, initiators and continuous phases, and sometimes includes emulsifiers, chain transfer agents and molecular crosslinkers to control molecular weight.

The emulsion polymerization step 1 is a step of preparing a hydrophilic core polymer emulsion sufficiently containing carboxylic acid groups. The core polymer contains monomers containing sufficient carboxylic acid to be neutralized with a neutralizing agent consisting of bases and to serve as a polymer dispersion stabilizer in the shell emulsion preparation stage of the second stage of polymerization. Examples of monomers containing carboxylic acids include acrylic acid, methacrylic acid, vinyl benzene acid and isopentyl benzene acid containing a single carboxylic acid and crotonic acid, itaconic acid, maleic acid, fmaric acid comprising two carboxylic acids And acid anhydrides thereof are used, and one or two or more of the above monomers are mixed and used.

In order to further reduce the content of the low molecular weight emulsifier in the core composition and to give polarity to the surface of the core particle to facilitate phase inversion, an anionic reactive emulsifier having a vinyl group which may be polymerized by radicals may be added. Examples of the anionic reactive emulsifiers include sulfonic acids with olefins, and the like, vinylsulfonic acid, arylsulfonic acid, metharylsulfonic acid, styrenesulfonic acid, acrylamido-alkyl sulfonic acid, and the like, which may be used alone or in combination.

Examples of other monomers include other vinyl compounds having one polymerized olefin in a molecule, alkyl, cycloalkyl, alkoxyalkyl acrylic acid or methacrylic esters having 1 to 18 carbon atoms and hydroxy alkyl having 2 to 8 carbon atoms. Acrylic acid or methacrylic acid esters; In addition, vinyl aromatic compounds composed of styrene and derivatives thereof, conjugate dienes having 4 to 9 carbon atoms, and other acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinyl acetate, vinyl propinate One kind or two or more kinds thereof may be used. If necessary, in order to increase the graft reaction with the shell composition to be polymerized later, one or two or more kinds of crosslinking monomers having two or more vinyl groups to be polymerized may be used. Examples include 1,4-divinylbenzene, aryl methacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, butanediol diacrylate, 1,4- Cyclohexane-diol-diacrylate, or 1,4-benzene-diol methacrylate.

The reason for neutralizing the core composition in the present invention is to disintegrate the primary particles forming the core particles to increase the number of particles per unit volume and also to form a pseudo water-soluble resin. Here, the purpose of increasing the number of particles per unit volume is to reduce the size of the final core / shell emulsion polymer particles, and the reason for the pseudo water-soluble resination of the core polymer is used as the polymer dispersant in the step of preparing the shell emulsion, which is the second step of polymerization. It is possible to prepare a core / shell emulsion polymer containing a minimum amount of emulsifier, and to give the paint composition containing the emulsified polymer with a plasticity viscosity behavior to improve spray workability, flow resistance, etc. This is to obtain a beautiful appearance and high gloss of the paint dry coating film. Therefore, the monomer containing a carboxyl group should contain 10-50 weight part with respect to a total of 100 weight part of a core polymer monomer. Generally, monomers containing carboxylic acids have different fractions present in the particles / particle surface / water phase due to differences in solubility in water. In the present invention, one or two or more kinds of monomers having a carboxyl group can be used.

In preparing the core emulsion in the present invention, one or two or more of the anionic reactive emulsifiers having vinyl groups may be selectively used to further reduce the content of the low molecular weight emulsifier and facilitate phase inversion.

Chain transfer agents may be added to control the molecular weight of the core polymer. Good chain transfer agents have high transfer activity and should not adversely affect the rate of polymerization other than giving an adjustable molecular weight distribution. For this reason, the amount of the chain transfer agent should be determined in consideration of the type and amount of the polymerization initiator. Generally, 0.1 to 0.5 parts by weight is used with respect to 100 parts by weight of the core monomer. Examples of the chain transfer agent that can be used include alkyl mercaptans having 2 to 15 carbon atoms, mercapto carboxylic acids having 2 to 8 carbon atoms, esters thereof, carbon tetrachloride and bromo trichloromethane.

The radical polymerization initiator can be used both water-soluble and oil-soluble initiators that form radicals by thermal dissociation at high temperatures and initiators that generate radicals by redox reactions at low temperatures, but the recommended initiators can impart polarity to the core surface. Water-soluble thermal dissociation radical initiator, and the amount used is 0.2 to 1.5 parts by weight based on 100 parts by weight of the core monomer. Examples of water soluble thermal dissociation initiators include ammonium, potassium, sodium persulfate and cyclohexyl hydroperoxide, cumene hydroperoxide, n-octyl hydroperoxide, t-butyl hydroperoxide, sec-butyl hydroperoxide Seeds or 1-phenyl-2methylpropyl-1-hydroperoxide and the like.

Emulsifiers are used either alone or mixed with one another or mixed with each other in order to accelerate the polymerization rate and to impart stability of the core emulsion, the amount is 0.2 to 2.0 parts by weight based on 100 parts by weight of monomers for anions, 0.1 for nonions It uses -1.0 weight part. Examples of emulsifiers include potassium laurate, potassium stearate, potassium oleate, sodium decyl sulfate, sodium dodecyl sulfate and sodium rosinate, linear or branched alkyl or alkylaryl polyethylene glycols or polypropylene glycol ethers and cioethers. And alkyl phenoxy poly (ethyleneoxy) ethanol, or a sulfated ammonium salt thereof, which is an adduct of 1 mol of nonylphenol and 5 to 12 mol of ethylene oxide.

The polymerization method of the core emulsion follows a semi-continuous process in which initial phase water and an emulsifier are added and initial initiator and monomer are injected in the same manner as the conventional emulsion polymerization method, and the reaction temperature is usually 70 to 90 ° C.

The core emulsion sufficiently containing the carboxylic acid group prepared by the above method is neutralized with a neutralizing agent consisting of a base for use as a polymer dispersant in a two stage shell emulsion polymerization. At this time, the swelling and dissolution behavior of the core polymers are competitive, and the factors influencing the competition behaviors are the type of neutralizing agent, the appropriate neutralization (pH value), the hydrophilicity of the core composition, and the core particle structure. In the present invention, it is possible to obtain a two-stage shell emulsion polymerization stability without containing an external low molecular weight emulsifier and to obtain a core-shell emulsion polymer containing a minimum amount of an emulsifier since the neutralized core emulsion serves as a polymer dispersant. Therefore, the swelling / dissolution competition behavior of the core polymer by neutralization, that is, the morphology of the neutralized core polymer should be controlled.

The neutralizers here are primary, secondary and tertiary amines such as inorganic bases ammonia, NaOH, KOH, LiOH and organic bases dimethylethanol amine, AMP 95 (manufactured by Angus) and triethyl amine. The degree of neutralization is the most important factor in the swelling / dissolution behavior of the core polymer. As the degree of neutralization increases, the dissolution behavior becomes stronger, so that the solubility of the core particles is accelerated, but the degree of neutralization does not give the stability of the two-stage shell emulsion polymerization. Therefore, in order to give stability of the two-stage emulsion polymerization, an appropriate degree of neutralization is required, and in the present invention, a neutralization degree of 7 to 75% is appropriate for the total amount of carboxylic acid groups of the core polymer, and the pH is 4.5 to 8.0.

Emulsion polymerization step 2 is a shell emulsion preparation step of preparing an emulsion without further adding an external low molecular weight emulsifier using the neutralized core polymer as a dispersion stabilizer. The monomers are used in combination with one or two or more of the monomers mentioned in the core manufacturing step, but are generally made more hydrophobic than the core composition and are selected according to the Tg of the core / shell polymer and the use of the final coating. .

In the present invention, the monomer composition of the two-stage shell polymer is 88 to 99.9 parts by weight of the monomer containing one olefin in the molecule relative to 100 parts by weight of the shell monomer composition among the monomers mentioned in the step of preparing the core emulsion polymer. And 0.1 to 12 parts by weight of a crosslinkable monomer containing two or more olefins in the molecule to prepare a shell polymer. In addition, in order to achieve a gel structure, 0.2 to 12 parts by weight of a crosslinking monomer having two or more reactive olefins is added in principle, and a particularly preferable crosslinking agent is a strong hydrophobic monomer such as 1,4-divinylbenzene.

The initiator in the shell composition may use a water-soluble initiator and a water-soluble initiator in order to make the shell composition nonpolar as in the core composition. Polymerization is also possible in the form of their redox initiators. The amount used is from 0.1 to 1.5 parts by weight based on 100 parts by weight of the monomers used in the two stage polymerization. Examples of oil-soluble initiators include dialkyl peroxides such as t-butyl benzoperoxide and 2,2'-azobis (isobutyrotytrile), 2,2'-azobis (methylbutyronitrile), 1,1 ' Compounds such as azobis (1-cyclohexane carbonitrile), and examples of reducing agents for water-soluble and oil-soluble initiators include alkali metal sulfite, hypo sulfite and sodium formaldehyde sulfoxylate. In the shell composition, the low molecular weight emulsifier is not contained.

The ratio of the polymerization monomers of the first stage core polymer and the second stage shell polymer is preferably 1: 0.5 to 1:20, more preferably 1: 1 to 1:15. The two-stage emulsion polymerization method is followed by a semi-continuous process in which water and a neutralized core emulsion are initially added and then an initiator and a monomer are added, but the polymerization temperature is 60 to 90 ° C. In addition, the reaction phase may optionally use a co-solvent which is a water phase alone or a mixed phase of butyl cellosolve, ethyl cellosolve, and texanol (available from Eastman) and water used as a coating film-forming solvent in coating applications.

The core / shell emulsions thus prepared are adjusted to pH 8-10 with the above-mentioned neutralizing agents for imparting storage stability and for application in paints. The amount of the final coating of the reversed phase core / shell emulsion polymer is used 33 to 75% by weight, when less than 35% by weight may cause poor coating film formation, adhesion failure, coating film splitting, etc., if it exceeds 75% by weight Due to the relatively low pigment content, hiding power and impact resistance may be lowered.

In the present invention, by replacing a certain amount of the relatively expensive extender pigment used in the existing paint application with an acrylic emulsion polymer, it is designed for the purpose of reducing raw material cost and improving the abrasiveness, drying property, salability and absorbing external impact after drying the coating film. , Manufactured.

In preparing the emulsion polymer of the present invention, an elastomeric rubber core particle formed by the reaction of an acrylic monomer having a relatively low Tg and a small amount of a crosslinking agent, a hard shell polymer composed of an acrylic monomer having a relatively high Tg, and a core between the two phases are formed. It comprises an interlayer copolymer consisting of one or more monomers and one or more monomers forming a shell, the emulsion is polymerized by the monomer continuous composition addition method, the inner skin of the copolymer is a soft copolymer consisting mostly of the core-forming monomer, A special particle structure, which is a hard copolymer composed mostly of shell-forming monomers, is produced, and by this method, acrylic monomers having a high Tg in a shell polymer forming step are made of a graft resin that completely encapsulates elastomeric rubber core particles. It is characterized by. In particular, the acrylic core shell emulsion polymer has a soft copolymer composed of 40 to 70% by weight of a core of an elastic rubber composed of an acrylic monomer having a relatively low Tg and a small amount of a crosslinking agent, and an innermost portion of a core formed of a core forming monomer crosslinking agent. Is 10-30% by weight of the interlayer copolymer having a special particle structure in which the hard copolymer composed of the shell-forming monomer is present, and 10-30% by weight of the hard shell composed of acrylic monomer having a relatively high Tg, It is added in an amount of 4 to 8% by weight based on the total water-soluble coating composition. If the emulsion polymer used is less than 4% by weight, the impact resistance effect is extremely slight, and the upper layer and smoothness of the coating film are lowered. In storage, it may cause a decrease in shelf life by increasing the interlaboratory force with the microgel.

The acrylic monomers used in the entire emulsion polymerization step of the present invention include monomers alone or butyl acrylate, 2-ethylbutyl acrylate, 2-ethylhexyl acrylate, and methyl meta in alkyl acrylates having 1 to 8 carbon atoms. Acrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate and butyl methacrylate are used alone or in combination of two or more. In addition, as the crosslinking agent used in the emulsion polymerization, aryl methacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol dimethacrylate, 1,4-butanediol diacryl Latex, 6-hexanediol diacrylate, and the like. In addition, the method of adding a continuous composition change used in the emulsion polymerization is disclosed in Korean Patent No. 79058, the content of which is a continuous composition change of the shell-forming monomer mixture in the preparation of a core shell emulsion polymer having a hollow inside the particle. It is a method for preventing hollow depression during curing, even by emulsion polymerization by an addition method to impart toughness to the shell to reduce the thickness of the shell. Therefore, the particle size of the final emulsion polymer produced by the present invention is an average particle diameter of 100 to 500 nanometers. 45-75% by weight of an elastomeric rubbery core composed of an acrylic monomer having a Tg of 20 ° C. or less and a small amount of a crosslinking agent, and an endothelial soft copolymer composed of most of the core-forming monomers and a crosslinking agent, and is present in a range of 15-35% and 80% by weight. An acrylic emulsion polymer composed of 15 to 35% by weight of a hard shell composed of an acrylic monomer having a Tg of 캜 or higher is produced.

Pigment polishing effect is achieved by applying an emulsion polymer having a particle size of 200 to 400 nanometers in which the internally crosslinked rubber core is completely encapsulated in a hard shell having a Tg of 80 ° C. or higher. When the coating film was dried, the internally crosslinked rubbery cores were present as fine particles, thereby buffering the impact from the outside. In paint, it is fast-drying and stable film-forming performance by selection of coarse solvents considering dryness and film-forming property of coating film and maximizes workability and dispersibility of paint using nonionic dispersant. By applying the anti-foaming property of the polysiloxane-based additives to prevent the smoothing and cratering of the coating film, and by mixing properly with the cray and polyurethane thickener can prevent the flow of the paint and maximize the smoothness.

Pigments used in the water-soluble paints of the present invention include inorganic pigments such as titanium dioxide, carbon black and iron oxide, organic pigments such as phthalocyanine blue, phthalocyanine green, and perylene red, extender pigments such as barium sulfate and magnesium silicate, and zinc. Antirust pigments, such as phosphate, strontium chromate, and zinc chromate, are used and 15-25 weight% is used with respect to the water-soluble paint of this invention. If the pigment to be used is less than 15% by weight, it may cause the hiding power, the coating hardness, the drying property, etc., and if it exceeds 25% by weight, not only the interlayer adhesion and the mechanical properties between the coatings will be lowered but also the price will be increased. . The amount of the pigment used is preferably 10 to 15% by weight based on the total paint composition. In addition, the ratio of the extender pigments of the present invention is characterized in that the ratio of barium sulphate and magnesium silicate is 1: 1.5 to 1: 2, which facilitates water solubility and improves freshness to improve the smoothness and appearance of the coating. It is a composition that can be optimized. The amount of use thereof is preferably 6 to 12% by weight based on the total coating composition. Zinc phosphate, strontium chromate, zinc chromate and the like may be used in the case of the rust preventive pigment, but in the present invention, zinc chromate, which is a non-toxic rust preventive pigment, is used because of the toxicity and carcinogenic potential of chromium. The amount of use thereof is preferably 6 to 12% by weight based on the total coating composition. When less than 6% by weight, the iron corrosion resistance is insignificant, and when it exceeds 12% by weight, the price rises and the glossiness of the coating is reduced.

In addition, in the present invention, an additive is used to sufficiently exhibit the function of the water-soluble paint. In the present invention, the following five additives are used. First, in the coating composition of the present invention, a dispersant is added to the mill base to disperse the pigment in the resin in a uniform and stable primary particle state. In the present invention, a nonionic dispersant that effectively works on oil and inorganic pigments is used. The usage-amount shall be 0.5 to 2.0 weight% with respect to all the water-soluble coating compositions. The content of the dispersant increases and decreases in proportion to the oil absorption of the pigment used.If the dispersant used is less than 0.5% by weight, the pigment dispersibility is decreased, which requires considerable energy input to disperse the pigment, which leads to an increase in the production cost. do. When it exceeds 2.0 weight%, it becomes the cause of water resistance fall and price increase. Secondly, the paint composition of the present invention is most of the solvent is water, the structure of the surface smoothing agent and the wetting agent, the other additives have a structure of a surfactant, so that a large problem of bubbles generated during stirring or painting the paint composition do. Therefore, in the present invention, in order to improve such a problem, the polysiloxane-based antifoaming agent is used in the millbase manufacturing step and the paint finishing step. The amount of the antifoaming agent is 0.05 to 0.5% by weight based on the total paint composition. Dilution is carried out in the water or co-solvent to be introduced into the mill base and paint finishing step of the addition of the antifoaming agent. If the amount of use exceeds the above-mentioned range, it becomes a cause of coating film appearance defects such as poor wettability or cratering on the substrate. Third, in the paint composition of the present invention, a wetting agent of a polysiloxane-based wetting agent is added at the post-treatment stage in order to improve wettability with the base material when forming a coating film of a water-soluble paint. The amount of the paint composition is 0.1-1.0 wt% Shall be. In the case of the wetting agent, the surface tension of the paint is lowered to give the wettability with the base, but it should not exceed the suggested amount because it provides a cause of bubble generation. Fourth, in the paint composition of the present invention, in order to give the smoothness of the surface of the coating film, a leveling agent of an ionic acrylic copolymer system is added at the post-treatment stage, and the amount thereof is 0.5 to 1.5% by weight. . Fifth, the thickeners used in the paint compositions of the present invention have a high viscosity at low shear rates (0.001 to 0.1 S ^-1 ), such as when the paint composition is stored, thereby minimizing the precipitation of pigments with a relatively high specific gravity. At the same shear rate (100-1000 S ^-1 ), the viscosity decreases to facilitate the transfer, and high shear rate (10000-100000 S ^-1 ), such as when spraying paints. Viscosity is extremely low, so that the best atomization behavior, the viscosity is recovered at a low shear rate after small adhesion, and the flow of paint and the flow of pigment particles are controlled. In the present invention, a clay thickener and a poly-based thickener Urethane-based middle agent was used. The cray and polyurethane thickeners are added in a solid ratio of 1: 1 to 1: 2, and are added at 1.0 to 3.0% by weight in the total paint composition. The cray thickener is added to the mill base, and the polyurethane thickener is post-added. In principle. In the coating composition of the present invention, one or more co-solvents selected from the group consisting of 1-methoxy-2-propanol, butyl cellussolve, and butyl carbitol are added as co-solvents. To improve the atomization of the paint during painting, and to facilitate evaporation of the solvent by the azotrop phenomenon to improve the drying properties. The amount of the cosolvent used in the present invention is 2 to 4% by weight of 1-methoxy-2-propanol, 4 to 8% by weight of butylcellulose, 2 to 4% by weight of butylcarbitol, and the content of the solvent is 6 Let it be -12 weight%.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples and Examples, but the scope of the present invention is not limited to the following examples. Abbreviations and physical property measurement methods used in the following Preparation Examples and Examples are as follows.

DIW: deionized water.

CO-436: Sulfated ammonium salt of alkylphenoxypoly (5 moles of ethylene oxy) ethanol, manufactured by Rhone-poulenc.

APS: Ammonium Persulfate

SPS: Sodium Persulfate

AIBN: 2,2'-azobisisobutyronitrile

AMPS: Sodium salt of 2-acrylamido-2-methylpropanesulfonide manufactured by Lubrizol.

MMA: Methyl methacrylate

BA: Butyl methacrylate

MAA: methacrylic acid

2-HEA: 2-hydroxyethyl acrylate

1,6-HDDA: 1,6-hexanedioldiacrylate

SM: Styrene Monomer

2-EHA: 2-ethylhexyl acrylate

DVB: 1,4-divinyl benzene

How to measure

* 1) Particle size: measured using Malvern's Autosizer Lo-C Model laser light scattering analyzer.

* 2) Viscosity: measured in CS mode using 600 mm cone-plate method of Haake RS-100 Model.

Preparation Example 1

Preparation of Inverted Core / Shell Microgel Emulsion Emulsion Polymers

Composition of Monomer Mixture I

MMA 61.0 g

BA 33.9 g

MAA 21.5g

2-HEA 29.1 g

Composition of Monomer Mixture II

SM 367.4 g

2-EHA 76.3 g

2.9 g of AMPS was added to the monomer mixture I, followed by mixing. Then, a 2 L four-necked flask equipped with a nitrogen inlet thermometer, a cooler, and a stirrer was added with DIW 630.2 g, CO-436 1.0 g, and 27.4 g of the monomer mixture I mixed with AMPS. And the temperature of the reaction portion is raised to 80 ° C. When the temperature is maintained at 80 ° C., nitrogen is injected for 5 minutes to make the reaction part nitrogen, and then nitrogen is removed. 0.42 g of APS was dissolved in 28.3 g of DIW, and then injected into the reactor and aged for 1 hour.

An initiator solution having 0.4 g of SPS dissolved in 28.3 g of DIW was added dropwise for 10 minutes, and the remaining monomer mixture I containing AMPS and 0.5 g of CO-436 dissolved in 198.0 g of DIW were simultaneously dropped for 1 hour and then maintained for 1 hour. . Here, a neutralizer solution in which 1.5 g of NaOH was dissolved in 35.4 g of DIW was added for 20 minutes and then maintained for 10 minutes.

2.2 g of DVB and 0.82 g of AIBN are mixed with the monomer mixture II, and then aged for 1 hour after dropping for 2 hours. The reactor is cooled to 40 ° C. and a 20% aqueous NaOH solution is added dropwise to adjust the pH to 9.0-9.5. Filter off with a 200 mesh filter to remove the coagulum and leave for 1 day after packing. The solids of the finally prepared emulsion were 39.8 weight percent, pH was 9.20, particle size ^{* 1)} was 97 nm, viscosity ^{* 2)} was 270 poise at 1 sec ^-1 and 2.8 poise at 500 sec-1.

Preparation Example 2

Preparation of Acrylic Core Shell Emulsion Polymer

Into a 5-liter four-necked flask equipped with a thermometer, a dropping tank, a cooler and a stirrer, 825.5 parts by weight of ion-exchanged water and 2.73 parts by weight of sodium persulfate were added, and the temperature was raised to 86 ° C. When the temperature was maintained at 86 ° C., the total emulsion was prepared in 500 parts by weight of ion-exchanged water, 9.4 parts by weight of Rhodapex CO-436 (manufactured by Long Franca), 775.1 parts by weight of butyl acrylate and 3.89 parts by weight of 1,4-butanediol diacrylate. Add 38.7 parts by weight and hold for 10 minutes. At this time, since the heat is generated, the temperature is maintained at 86 ° C. and the total emulsion is slowly added dropwise at a rate of 10.4 parts by weight, and at the same time, an aqueous solution of 1.17 parts by weight of sodium persulfate is added at a rate of 0.43 parts per minute to 50.0 parts by weight of ion-exchanged water. do. After the dropping was completed, the mixture was aged for 90 minutes to prepare an elastomeric rubbery copolymer. It was 160 nanometers when the particle diameter at this time was measured with the light-scattering measuring apparatus. A first field made of 115.0 parts by weight of ion-exchanged water, 3.36 parts by weight of Rhodapex CO-436, 96.9 parts by weight of butyl acrylate, 96.9 parts by weight of 2-ethylhexyl acrylate, and 0.97 parts by weight of 1,4-butanediol diacrylate. An emulsion was prepared in a first supply tank, and a second total emulsion prepared from 115.0 parts by weight of ion-exchanged water, 1.15 parts by weight of Rhodapex CO-436, 175.3 parts by weight of methyl methacrylate and 18.4 parts by weight of butyl acrylate was added to the second supply tank. Prepare. An aqueous solution of 1.95 parts by weight of ammonium persulfate was added to 30.0 parts by weight of ion-exchanged water, and fed at a rate of 5.1 parts per minute from the second supply tank to the first supply tank having a stirring device, and reacted from the first supply tank. The polymerization proceeds while feeding the flask at a rate of 5.1 parts by weight per minute. After supplying the mixture of monomers was completed for 1 hour to prepare an interlayer copolymer. The particle diameter at this time was 196 nanometers. A total emulsion prepared from 270.0 parts by weight of ion-exchanged water, 1.95 parts by weight of sodium persulfate, 2.06 parts by weight of Rhodapex CO-436, 350.5 parts by weight of methyl methacrylate and 39.0 parts by weight of butyl acrylate was added dropwise at a rate of 9.5 parts by weight, After aging for 90 minutes, ammonia was added 21.0 parts by weight while cooling to room temperature to terminate the reaction. The elastomeric rubber-like core-layer copolymer-shell structure thus prepared had an average particle diameter of 210 nanometers, a solid content of 44.7%, a viscosity of 32 centipoise, and a pH of 9.8.

When the microgel resin prepared by the method of Preparation Example 1 is mixed with the acrylic core-shell emulsion polymer of Preparation Example 2, coloring pigments, extender pigments, rust preventive pigments, solvents, additives, etc. Containing acrylic core shell emulsion polymer which can improve the chemical and mechanical properties of coating film, especially solvent resistance, impact resistance, and rust resistance, even under dry condition at room temperature (25 ℃) or forced drying (60 ~ 80 ℃) It becomes a microgel coating composition.

The applied water-soluble coating composition is coated by spraying and immersion coating method on steel plate or plastic aluminum that has undergone the coating treatment such as zinc phosphate and iron phosphate, or the pretreatment such as sand blast, acid treatment, etc. It can be successfully used as an alternative paint for oil-soluble two-component paints, which are used as normal-temperature drying or forced-drying water-soluble industrial coatings that provide effects, or are currently used as primer paints for automobile repairs at home and abroad. The main required properties of automotive paint primer paints can be roughly classified into exterior, quick-drying, abrasiveness, eye comfort, top compatibility, etc.

The dispersant used in the examples below may be used BYK-190 (BYK CHEMIE) or Disperse-AYD W-30 (DANIEL PRODUCT) and the like, and the antifoaming agent BYK-024 (BYK CHEMIE) or FOAMEX 7447 (TEGO CHEMIE) ), And the cray thickener may be BENAQUA-4000 (RHEOX) or BENTONE AD (RHEOX) and the like, and as a wetting agent BYK-345 or BYK-346 (BYK CHEMIE), `or TEGO Glide450 (TEGO CHEMIE Co., Ltd.) may be used, and BYK-381 (BYK CHEMIE Co., Ltd.) was selected and applied as a leveling agent.

Example 1

Weight ratio of component I of paint (unit: weight%)

Microgel Resin of Preparation Example 1 54.82

Dispersant 0.65

Antifoam 0.54

Cray-based thickener 0.20

Carbon black 0.03

Titanium dioxide 6.98

Barium Sulfate 3.19

Magnesium Silicate 5.98

Zinc Phosphate 7.97

Ion Exchange Water 2.00

Acrylic Emulsion Polymer of Preparation Example 3.99

Weight ratio of component II of paint

1-methoxy2-propanol 2.99

Butyl Cellulose 4.98

Butylcarbitol 1.99

Wetting agent 0.20

Leveling agent 0.50

Ion Exchange Water 1.99

Polyurethane thickener (10% water) 0.50

Ammonia solution (25% solution) 0.50

Each component of Component I described in Example 1 was added with stirring sequentially, premixed for 20 minutes, and then uniformly dispersed to a dispersion particle size of 15 micrometers or less using a high speed stirrer and a pearl mill to prepare a mill base. . Meanwhile, the components of Component II are stirred and mixed in a separate container for 20 minutes, and the mixed solution is added to the mill base while stirring. The water-soluble coating composition thus prepared was 49.06% solids, pH 8.6, surface tension 33.5 dyne / cm.

Comparative Example 1

Composition of paints (unit: wt%)

XK-62 (acrylic emulsion of ZENECA) 53.84

Dispersant 0.65

Antifoam 0.54

Cray-based thickener 0.20

Carbon black 0.03

Titanium dioxide 6.98

Barium Sulfate 3.19

Magnesium Silicate 7.76

Zinc Phosphate 7.97

Ion Exchange Water 5.18

1-methoxy2-propanol 2.99

Butyl Cellulose 4.98

Butylcarbitol 1.99

Wetting agent 0.20

Leveling agent 0.50

Ion Exchange Water 4.49

Polyurethane thickener (10% water) 0.50

Ammonia solution (25% solution) 0.50

The production process was the same as in Example 1 except that the main resin in Example 1 was applied with XK-62 resin, which is an acrylic emulsion resin of ZENECA, and the acrylic core shell emulsion was removed and replaced with magnesium silicate of a corresponding solid content. The water-soluble coating composition was prepared. In the case of the paint prepared in Comparative Example 1, the solid content was 50.74%, pH 8.8, and surface tension of 33.7 dyne / cm.

Comparative Example 2

Composition of paints (unit: wt%)

Microgel Resin of Preparation Example 1 54.82

Dispersant 0.65

Antifoam 0.54

Cray-based thickener 0.20

Carbon black 0.03

Titanium dioxide 6.98

Barium Sulfate 3.19

Magnesium Silicate 5.98

Zinc Phosphate 7.97

Ion Exchange Water 1.99

Acrylic Emulsion Polymer of Preparation Example 3.99

1-methoxy2-propanol 2.99

Butyl Cellulose 4.98

Butylcarbitol 1.00

Wetting agent 0.20

Leveling agent 0.50

Ion-Exchanged Water 2.99

Polyurethane thickener (10% water) 0.50

Ammonia solution (25% solution) 0.50

This comparative example 2 is for examining the effect when a coagulant deviates from a preferable addition amount. In the case of the paint prepared in Comparative Example 2, the solid content was 49.06%, pH 8.6, and surface tension 33.6 dyne / cm.

Comparative Example 3

Composition of paints (unit: wt%)

Microgel Resin of Preparation Example 1 56.82

Dispersant 0.65

Antifoam 0.54

Cray-based thickener 0.20

Carbon black 0.03

Titanium dioxide 6.98

Barium Sulfate 3.19

Magnesium Silicate 5.98

Zinc Phosphate 7.97

Ion Exchange Water 1.99

Acrylic Emulsifier 1.99 of Preparation Example 2

1methoxy2-propanol 2.99

Butyl Cellulose 4.98

Butylcarbitol 1.99

Wetting agent 0.20

Leveling agent 0.50

Ion Exchange Water 2.00

Polyurethane thickener (10% water) 0.50

Ammonia solution (25% solution) 0.50

This comparative example is to examine the effect when the acrylic core shell emulsion polymer is out of the preferred amount range. In the case of the paint prepared in Comparative Example 3, the solid had a property of 48.96%, pH 8.7, and surface tension of 33.5 dyne / cm.

Comparative Example 4

It is a paint composition which is mixed with the weight ratio 3.4: 0.6 of UU2700-A (the subject) and UU2700-B (the hardener) which are currently available for the serviceability of the two-component automotive repairs of KOREA CHEMICAL. Paints and coating properties of the industrial anticorrosive primers and automotive repair intermediate coatings of the respective Examples and Comparative Examples are shown in Tables 1 and 2, respectively.

* Condition in container: No streaks, foreign objects, hard lumps, evenly distributed.

* Spray / Dip Coating Workability

:-Atomization and painting appearance when spray coating.

-Painting appearance and precipitation / bubble occurrence during deposition coating.

* Particle size: It should be 15 micrometer or less when measured with particle size after millbase dispersion.

* Paint storage: Within 10% of the viscosity change within 6 months of paint storage, there should be no precipitate that cannot be released when stirred.

* Adhesiveness: Glass tape adhesiveness should be more than 90/100 after cross cutting at 1mm interval.

* Water resistance: After deposition for 120 hours at room temperature, there is no discoloration and gloss change after standing for 1 hour at room temperature.

* Impact resistance: It should not be cracked when testing 500g / 20cm / 1.5 inch with Dupont type impact tester.

* Corrosion resistance: Salt Fog test equipment according to ASTM B-117, shall not corrode more than 3mm after 120 hours test.

* Weather resistance: It should be less than delta E 3.0 and gloss coverage more than 80% at 24 months of outdoor exposure at horizontal angle of 45 °.

* Accelerated weather resistance: It shall be discoloration Delta E 3.0 or less after 1000 hours of exposure to accelerated weather resistance test equipment such as QUV or WOM, and gloss retention rate is 80% or more

* Drying: Drying time maintained at 60 ~ 80 ℃ based on body temperature with IR drying device.

* Abrasiveness: Attach # 320 abrasive paper to the automatic polishing machine, and it is easy to grind when polishing, and no abrasive powder is attached to the abrasive paper.

* Top coat appearance: This item is for automobile repair, and it is evaluated as gloss, clearness, and leveling after finishing top coat in the middle of the painting.

As described above, the composition according to the present invention improves the chemical resistance of the existing water-based coatings by introducing an acrylic core shell emulsion polymer having excellent weatherability and impact resistance into a microgel resin having excellent water resistance, corrosion resistance, and dryness. There is an effect of improving adhesion to the old film, abrasiveness, rust resistance, impact resistance and the like.

Claims (5)

33 to 75% by weight of a microgel emulsion having a reversed phase core / shell morphology, 4 to 8% by weight of an acrylic core / shell emulsion, 15 to 25% by weight of a pigment consisting of a coloring pigment, an extender pigment and an rust preventive pigment, and a coarse agent 6 to 12% by weight, 0.2 to 2.0% by weight of dispersant, 0.1 to 1% by weight of polysiloxane wetting agent, 0.05 to 0.5% by weight of polysiloxane antifoaming agent, 0.5 to 1.5% by weight of ionic acrylic copolymer leveling agent and 1 to 3% by weight of thickener A microgel water-soluble coating composition containing an acrylic core shell emulsion polymer, characterized in that it contains. The method of claim 1, wherein the microgel emulsion having a reversed phase core / shell morphology contains 10 to 50 parts by weight of a monomer containing a carboxylic acid group in the molecule relative to 100 parts by weight of the core monomer composition, containing one olefin in the molecule 50 to 90 parts by weight of a non-crosslinkable monomer, and optionally a crosslinking monomer and / or an anionic reactive emulsifier containing two or more olefins in a molecule are added and reacted to prepare a core emulsion polymer and to prepare a core emulsion polymer. A first step of preparing a pseudo water-soluble resin by adding 0.5 to 1.2 equivalents of a neutralizer to 1 equivalent of carboxylic acid; And a shell emulsion prepared by reacting 88 to 99.9 parts by weight of a non-crosslinkable monomer containing one olefin in a molecule and 0.1 to 12 parts by weight of a crosslinkable monomer containing two or more olefins in a molecule with respect to 100 parts by weight of the shell monomer composition. A microgel water-soluble coating composition containing an acrylic core shell emulsion polymer, which is prepared by reacting a polymer in a weight ratio of 1: 0.5 to 1:20. The method of claim 1, wherein the acrylic core / shell emulsion polymer emulsion-polymerized elastomeric rubber core consisting of a relatively low Tg acrylic monomer and a small amount of crosslinking agent, the core forming monomer and shell in the presence of the emulsion polymerized core particles Emulsion-polymerization of the forming monomer mixture by the continuous composition change addition method, the inner skin is a soft copolymer composed mostly of core-forming monomer and a crosslinking agent, the outer shell is a special copolymer having a hard copolymer consisting of a shell-forming monomer having a relatively high Tg A microgel water-soluble coating composition containing an acrylic core shell emulsion polymer is prepared by preparing an interlayer copolymer having a particle structure and then emulsion polymerizing the final hard shell in the presence of the interlayer copolymer. According to claim 1 or claim 3, wherein the acrylic core shell emulsified polymer is 45 to 75% by weight of an elastomeric rubber core composed of a relatively low Tg acrylic monomer and a small amount of crosslinking agent, the endothelial is mostly made of a core forming monomer and a crosslinking agent. A soft copolymer composed of 15% to 35% by weight of an interlayer copolymer having a special particle structure in which a hard copolymer composed of shell-forming monomers is present, and a shell composed of an acrylic monomer having a relatively high Tg. A microgel water-soluble coating composition containing an acrylic core shell emulsion polymer, characterized by consisting of 15 to 35% by weight. The microgel water-soluble coating composition according to claim 1, wherein the crosslinking monomer containing two or more olefins in the molecule is 1,4-divinylbenzene.