KR0149696B1 - Method for preparing emulsion polymers having core-shell structure by two-step emulsion polymerization and paint composition containing the same - Google Patents

Abstract

The present invention relates to a method for preparing a two-stage emulsified neutralizer having a core-cell structure containing a minimum amount of an emulsifier and to a coating composition containing the emulsified polymer, and more particularly, to a method prepared by an existing emulsion polymerization method. The neutralized core emulsion containing sufficient carboxylic acid groups was neutralized with a neutralizing agent to prepare a stable two-stage cell emulsion without the addition of an external low molecular weight emulsifier using the neutralized one-stage core emulsion as a polymer dispersant. A method for producing a stable emulsion polymer of core-cell structure containing a low molecular weight emulsifier and a coating composition containing such an emulsion polymer.

According to the present invention, the water resistance, alkali resistance, rust prevention property, and adhesion of the paint dried coating film are improved, and a beautiful appearance and high gloss are obtained.

Description

Method for preparing emulsion polymer of core-cell structure by two-step emulsion polymerization method and coating composition containing same

The present invention relates to a method for producing an emulsion polymer by a two-step emulsion polymerization method having a core-cell structure containing a minimum amount of an emulsifier, and more specifically to a coating composition comprising the emulsion polymer. By neutralizing the core emulsion containing a sufficient amount of the carboxylic acid group produced by the law with a neutralizing agent, and by using a polymer dispersant, the neutralized one-phase core emulsion to prepare a stable secondary cell emulsion without containing an external low molecular weight emulsifier Ultimately, a method of preparing a stable emulsion polymer having a core-cell structure containing a minimum amount of a low molecular weight emulsifier, and including such an emulsion polymer in the paint to improve the water resistance, alkali resistance, rust resistance, and adhesion of the paint dry coating film, It relates to a coating composition that gives a beautiful appearance and high gloss.

The emulsion polymer composition contains a nonionic or ionic low molecular weight emulsifier or dispersant as a dispersion stabilizer, which forms a stable micelle in the water phase to provide a polymerization site where vinyl monomers can be radically initiated polymerized, as well as the resulting emulsion polymer. It functions to stably disperse the particles in the water phase. For this purpose, 0.5 to 2% by weight of emulsifier was used in the conventional emulsion polymerization, and these emulsifier molecules remain in the paint dry coating film, reducing adhesion to the substrate and providing a path for water penetration. This adversely affected the water resistance, alkali resistance and rust resistance.

Thus, an emulsifier-free emulsifying method has been developed as a method for solving the above problems due to emulsifiers, the basic concept of which not only provides stability of emulsion particles without using the low molecular weight emulsifiers described above. Finally, it acts as a dispersion stabilizer for polymers that act as main resins for paints.

The above patents use a water-soluble resin prepared by neutralizing a solution polymer containing a carboxyl group with a neutralizing agent as a dispersion stabilizer for secondary emulsion polymerization, and the water-soluble-emulsion composite resin prepared therefrom is a main resin of a paint composition requiring high gloss. It is recommended.

US Pat. No. 4,465,803 to Kansai Paint discloses a water-soluble vinyl polymer obtained by solution polymerization of a vinyl monomer having an unsaturated double bond and an unsaturated monomer comprising a carboxylic acid, and neutralizing it with a neutralizing agent. EP 450,451 discloses an example in which a water-soluble resin obtained by neutralizing a primary copolymer obtained by solution polymerization of maleic anhydride and an alpha-olefin with a neutralizing agent is applied as a dispersion stabilizer for secondary emulsion polymerization.

Table 1 shows the characteristics and performance of the water-soluble resin, water-dispersible resin and emulsion resin,

Emulsion resin is excellent in mechanical properties, that is, water resistance, alkali resistance and weather resistance, but the gloss and pigment dispersibility is inferior to water-soluble resin, the coating composition containing the emulsion resin is smoothness of the paint during brush or roller coating work It is not so good that the brush or roller marks remain in the paint drying coating, which does not give a beautiful appearance, and the gloss is low. Generally, the emulsion coating composition which requires gloss is water-soluble acrylic and polyurethane to improve pigment dispersibility and improve smoothness. It includes polyester, alkyd, or epoxy resin, there is a problem that becomes unstable due to the organic solvent and additives added during the paint production is sufficient or solidification occurs.

For this reason, as mentioned in the above patent, in order to impart stability of the two-stage emulsion polymerization, not only the function of the dispersion stabilizer but also the function of the main resin of the coating composition, the water-soluble resin is included in the preparation of the resin so that the above-mentioned, unstable enough And while solving the problem of coagulation, the excellent mechanical properties of the emulsion to complement the high gloss and pigment dispersibility of the water-soluble resin.

However, since the patent uses a solution polymerization method using an organic solvent in the preparation of the water-soluble resin, it must undergo a complicated process of extracting the solvent under reduced pressure after neutralization, and the solid content of the water-soluble resin and the emulsion resin prepared therefrom is 1 There is a problem in that the productivity is low because polymerization stability is obtained when: 5 or less.

Two-stage latex polymers are known to exist in various morphology forms, which are determined by factors such as the relative hydrophilicity, miscibility, and molecular weight between the first and second stage polymers.

The core-cell structure is a form in which a two-stage polymer forms a cell and surrounds the core one-stage polymer. US Pat. No. 4,515,914 discloses a styrene / butadiene core polymer prepared in one stage as a two-stage mono vinyl cell polymer. One example of a core-cell latex that encapsulates is described. As such, the core-cell structure consists of a hydrophobic core polymer and a hydrophilic cell polymer.

In contrast, J. Poly. Published by Lee and Ishikawa. Sci., 21, 147-154 (1983) The inverse core-cell structure in The Formation of Inverted Core-Shell Latexes is a structure in which the polymer produced in step 2 becomes the core and is encapsulated by the polymer produced in step 1 The first stage polymer should have sufficient hydrophilicity to allow the polymer to be solubilized by a change in pH, and the second stage polymer should have sufficient hydrophobicity so that the polymer is not solvated by a change in pH.

Factors affecting the formation of latex having an inverse core-cell structure include not only the hydrophilicity of the hydrophilic polymer mentioned above, but also interfacial tension, molecular weight, and the like, and are affected by the degree of phase separation of the hydrophilic and hydrophobic polymer.

European Patent No. 338,486 of S. Johnson & Johnson, Inc. reports the preparation of a latex having an inverse core-cell structure by adjusting the pH of the hydrophilic polymer prepared in step 1 and then mixing / polymerizing it with the step 2 hydrophobic monomer. have.

Accordingly, the present invention is to apply a method of producing a "similar water-soluble resin" which makes the manufacturing process simpler without going through a complicated solvent removal step in producing a water-soluble resin used as a dispersion stabilizer in emulsion polymerization, and the conventional emulsification By neutralizing the core emulsion containing a sufficient amount of carboxylic acid groups produced by the polymerization method with a neutralizing agent, the polymer dispersant which enables the preparation of a stable two-stage cell emulsion without containing the external low molecular weight emulsifier is thus prepared. It is an object of the present invention to provide a method for preparing an emulsion polymer having a core-cell structure by a two-step emulsion polymerization method in which the core-cell emulsion polymer of the present invention thus prepared contains a minimum amount of an emulsifier.

In addition, the core-cell emulsified polymer of the present invention is included as a main resin of the coating composition, so that sufficient or no solidification does not occur during the storage of the coating, which gives a beautiful appearance and high gloss when the coating is applied to the coating, and has water resistance, alkali resistance and It is an object of the present invention to provide a coating composition that also provides excellent weather resistance.

The emulsion composition of the present invention is prepared by a two-step emulsion polymerization method having a core-cell structure, and the detailed composition and manufacturing process for each step are as follows.

Emulsion polymerization herein refers to a process that requires water as monomers, initiators and continuous phases, sometimes including a chain regulator and a crosslinking agent to control the molecular weight of the emulsifier.

A. Emulsion Polymerization Stage 1

The first step of emulsion polymerization is the preparation of a hydrophilic core polymer emulsion containing sufficient carboxylic acid groups. The step of neutralizing the core polymer with a neutralizing agent consisting of a base is sufficient to serve as a polymer dispersion stabilizer in the second step of preparing a cell emulsion. Monomers containing an acid are contained.

Examples of monomers comprising 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 and two carboxylic acids; Acid anhydrides thereof are used, and one or two or more of the above monomers are mixed and used.

In addition, as monomers that can be used in combination with the monomer containing the carboxylic acid group, there are monomers having a vinyl group which can be polymerized by radicals, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, Isopropyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate Alkyl or cycloalkyl acrylic acid or methacrylic acid esters having 1 to 18 carbon atoms, such as butyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, lauryl methacrylate and cyclohexyl methacrylate Methoxy butyl acrylate, methoxy butyl methacrylate, methoxy Alkoxy alkyl acrylic or methacrylic acid esters such as ethyl acrylate, methoxy ethyl methacrylate and 2-hydroxy ethyl acrylate, 2-hydroxy ethyl methacrylate, 2-hydroxy propyl acrylate, 2-hydroxy Hydroxy alkyl acrylic acid or methacrylic acid ester having 2 to 8 carbon atoms such as propyl methacrylate. Also styrene, alpha-methyl styrene, ortho-methyl styrene, meta-methyl styrene, para-methyl styrene, ortho-ethyl styrene, meta-ethyl styrene, para-ethyl styrene, ortho-methyl-para-isopropyl styrene , Vinyl aromatic compounds such as para-chloro styrene, ortho, para-dichloro styrene, para-chloro styrene, ortho, para-dibromostyrene, para-bromostyrene, and 1,3-butadiene, 2-methyl- Conjugated dienes having 4 to 9 carbon atoms such as 1,3-butadiene, 2,3-dimethyl-1,3butadiene, pentadiene, 2-neopentyl-1,3butadiene, and others acrylonitrile, methacrylonitrile, etc. This can be used.

As will be described in detail below, the reason for neutralizing the core polymer in the present invention is to dissociate the initial particles forming the core particles to increase the number of particles per unit volume to form a pseudo water-soluble resin. The purpose of increasing the number of particles per unit volume here is to reduce the size of the final core-cell emulsion polymer particles, and the reason for the pseudo water-soluble resination of the core polymer is the minimum amount used as the polymer dispersant in the step of preparing the cell emulsion, which is the second stage of polymerization. It is not only able to manufacture the core-cell emulsion polymer containing the emulsifier of, but also to improve the smoothness of the coating composition containing the emulsion polymer, so as to obtain the fine appearance and high gloss of the paint dry coating film.

For this reason, the monomer containing a carboxylic acid group should be contained in 10-40 weight part with respect to a total of 100 weight part of core polymer monomers.

In preparing the core emulsion in the present invention, the composition of the monomer is 0 to 50 parts by weight of alkyl or cycloalkyl acrylic acid or methacrylic acid ester having 1 to 18 carbon atoms and alkoxy alkyl acrylic acid or meta to 100 parts by weight of the total monomers. 0 to 5 parts by weight of acrylic acid ester, 0 to 10 parts by weight of hydroxy alkyl acrylic acid or methacrylic acid ester having 2 to 8 carbon atoms, 0 to 90 parts by weight of vinyl aromatic compound, 0 to 5 parts by weight of conjugated diene having 4 to 9 carbon atoms It consists of 10-40 weight part of monomers containing 0-30 weight part of acrylonitrile, methacrylonitrile, and carboxylic acid.

And if necessary, ie, to increase the molecular weight of the polymer to obtain excellent mechanical properties, a crosslinking agent is involved, such as ethylene glycol dimethacrylate, glycerol diacrylate, 1,4-cyclohexane-diol-da. Acrylate, 1,4-benzene-diol methacrylate, and the like.

In addition, a chain conversion agent is used to control the molecular weight of the core polymer. In the present invention, since the solid content of the core emulsion is prepared at 8 to 15% by weight, the degree of neutralized core emulsion when neutralized with a neutralizing agent is not very high. The dry coat gloss of paints applied with core-cell emulsion polymers prepared using chain converting agents was about 2-3 higher.

A good chain converting agent has a high chain converting capacity, and in addition to giving an adjustable molecular weight distribution, the polymerization rate should not adversely affect. For this reason, the amount of the chain converting agent should be determined in consideration of the type and amount of the polymerization initiator, and generally 0.1 to 0.5 parts by weight is used for 100 parts by weight of the core monomer. Examples of chain converting agents that can be used include mercaptoacetic acid having 2 to 8 carbon atoms, such as mercaptoacetic acid, 2-mercapto propionic acid, 3-mercapto propionic acid, 2-mercapto benzene acid, mercapto succinic acid and mercapto isophthalic acid, etc. Carboxylic acids and their esters, carbon tetrachloride, bromotri chloromethane and the like are also used.

Radical polymerization initiators can be used both as initiators that generate radicals by thermal dissociation at high temperatures and by which redox reactions are produced by redox reactions at low temperatures, but in the present invention, thermal dissociation initiators are used to obtain the best results. The amount is 0.2 to 1.5 parts by weight based on 100 parts by weight of the core monomer, and examples thereof include ammonium, potassium, sodium persulfate, cyclohexyl hydroperoxide, cumene hydroperoxide, n-octyl hydroperoxide and t-butyl Water-soluble thermal dissociation initiators such as hydroperoxide, sec-butyl hydroperoxide, 1-phenyl-2-methylpropyl 1-hydroperoxide and the like are used.

Emulsifiers are used either alone or mixed with each other or mixed with each other in order to accelerate the polymerization rate and 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 anion, non-ionic 0 to 1.0 parts by weight is used.

The polymerization method of core emulsion is based on the process of initial injection of a continuous phase water and an emulsifier like the conventional emulsion polymerization method, and the injection of an initiator and a monomer, and the reaction temperature is 75-85 degreeC.

B. Core Emulsion Neutralization Step

The core emulsion sufficiently containing the carboxylic acid group prepared by the above method is thickened with a neutralizing agent consisting of a base for use as a polymer dispersant in a two-step cell emulsion polymerization step, wherein the core polymer is competitive with each other in swelling and dissolution behavior. The factors that decisively affect this competition behavior are the type of neutralizing agent, the appropriate degree of neutralization (pH value) and the core particle structure.

In the present invention, it is possible to obtain a two-stage cell emulsion polymerization stability without containing an external low molecular weight emulsifier, and to obtain a core-cell emulsion polymer containing a minimum amount of emulsifier, so that the neutralized core emulsion serves as a polymer dispersant. Therefore, the core technology of the present invention is a method of controlling the swelling / dissolution competition behavior of the core polymer by neutralization, that is, the morphology of the neutralized core polymer.

The neutralizing agents used in the present invention are primary, secondary and tertiary amines such as inorganic bases ammonia, NaOH, KOH, LiOH and organic bases dimethyl ethanolamine, 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 and the solubility of the core particles is promoted, but too high the degree of neutralization does not give stability to the two-stage cell emulsion polymerization. In order to give stability of the step emulsion polymerization, an appropriate degree of neutralization is required, and in the present invention, a degree of neutralization of 5 to 75% is appropriate for the total amount of carboxylic acid of the core polymer, and the pH is 4.5 to 8.0.

C. Emulsion Polymerization Stage 2

Emulsion polymerization step 2 is a cell emulsion preparation step of preparing an emulsion without the addition of an external low molecular weight emulsifier using the neutralized core polymer as a dispersion stabilizer.

Monomers are used by mixing one or two or more of the monomers mentioned in the core manufacturing step of the first step, depending on the glass transition temperature of the core-cell polymer and the use of the final paint.

In the present invention, the monomer composition of the two-stage cell polymer is 1-70 parts by weight of alkyl or cycloalkyl acrylic acid or methacrylic acid ester having 1 to 18 carbon atoms, alkoxy alkyl acrylic acid or methacrylic acid ester with respect to 100 parts by weight of monomer. Parts by weight, 0-15 parts by weight of hydroxy alkyl acrylic acid or methacrylic acid ester of 2 to 8 carbon atoms, 12-88 parts by weight of vinyl aromatic compound, 0-5 parts by weight of conjugated diene of 4 to 9 carbon atoms, acrylonitrile, It consists of 0-30 weight part of methacrylonitrile and 0-8 weight part of monomers containing carboxylic acid.

The initiator uses a water-soluble initiator consisting of ammonium or alkali metal persulfate and an oil-soluble initiator used in the core polymer production step, and the amount of the initiator is 0.1 to 1.5 parts by weight based on 100 parts by weight of the monomer used in the two-stage polymerization.

Examples of oil-soluble initiators include dialkyl peroxides such as t-butyl benzoperoxide, 2,2'-azobisisobutyronitrile, 2,2'-azobismethylbutyronitrile, 1,1'-azobis- Azo compounds such as 1-cyclohexane carbonitrile.

In addition, the low molecular weight emulsifier is characterized in that it does not contain.

The ratio of the first stage core polymer and the second stage polymerization monomer is preferably 1: 4 to 1:20, and most preferably 1: 10.5 to 1:15.

The two-step emulsion polymerization method is a step of initially inserting the neutralized core emulsion and water, followed by an initiator and a monomer. The polymerization temperature is 75 to 84 ° C.

In addition, the reaction phase is a water phase alone or a mixture of water and a high boiling point solvent such as butyl cellosolve, ethyl cellosolve, and texanol (available from Eastman Co., Ltd.), which are used as coating solvents for coating film formation, is used. 0 to 200 parts by weight is used for 100 parts by weight of the emulsion.

The core-cell emulsion thus prepared adjusts the pH to 8-10 with the above-mentioned neutralizing agent for imparting storage stability and for application to paints.

D. Preparation of Paint Composition

The pseudo water-soluble emulsion containing the minimum amount of the low molecular weight emulsifier prepared by the present invention is used as the main resin of the high gloss paint, so that the resin solid content is 15 to 30 parts by weight based on 100 parts by weight of the paint.

Pigment and additives (antifreeze, antifoaming agent, pH adjusting agent, coarse solvent, dispersant) are blended in the mill base, and the mixture is stirred at 2000-3000 RPM for about 90 minutes and dispersed to a particle size of 5 micrometers or less.

Dispersant uses a nonionic and anionic dispersant, 0.2 ~ 0.7 parts by weight.

In the case of a white paint, various types of titanium dioxide are used alone, and in the case of a colored paint, red iron oxide, yellow iron oxide alone, or a mixture of titanium dioxide and an organic pigment is used. In the case of white paint, the amount of pigment is used so that the pigment volume percentage (PVC) is 10-30.

Defoamer is added by dividing the defoamer of siloxanes into the same amount in mill base and finishing stage, but the total amount uses 0.05-0.5 weight part with respect to 100 weight part of paint.

pH adjuster uses AMP 95 (manufactured by Angus), ammonia, dimethylethanolamine and 0.1 to 0.2 parts by weight based on 100 parts by weight of paint.

In addition, in order to prevent the flow of the coating composition and to smooth the coating, a thickening agent is used. A nonionic polyurethane-based auxiliary thickening agent is used alone or in combination with an ASE thickener. The amount used is 0.5 to 2.5 parts by weight based on 100 parts by weight of paint when using polyurethane thickener alone, and 0.2 to 1.0 parts by weight of polyurethane based on 0.5 parts by weight of paint based on 100 parts by weight of ASE based Use 1.0 parts by weight.

A high boiling point solvent is used as a cosolvent for forming a coating film, and the amount is 5 to 10 parts by weight based on 100 parts by weight of the resin solids used. If the amount is 5 parts by weight or less, cracks occur in the coating in winter and 10 parts by weight. If it is more than a portion, stickiness occurs in the coating in summer.

In the following preparation, the method of preparing the emulsion composition of the present invention will be described in more detail. The examples show the performance of the coating composition containing the emulsion, but do not limit the scope of the present invention.

Core Preparation

[Production Example 1]

Into a four-necked flask equipped with a nitrogen inlet, thermometer, cooler and stirrer, add 803.3 parts by weight of distilled water and 3.0 parts by weight of sodium dibenzenesulfate and raise the temperature of the reaction to 80 ° C. To make the reaction part in a nitrogen atmosphere, and then remove nitrogen.

Next, 15.5 parts by weight, which is 10% of the monomer mixture described below, is added thereto, followed by adding 2.33 parts by weight of ammonium persulfate, which is a radical polymerization initiator, and 10 parts by weight of distilled water solution.

After holding for 10 minutes, the remaining monomer mixture was injected for 90 minutes, aged for 1 hour, and then the conversion rate If it is measured and 97% or more, it cools to 30 degreeC. Filter off with a 400 mesh filter to remove the coagulum.

The prepared core emulsion had a solids content of 15.8 percent, a pH of 2.3, and a particle size. Is 35 mm.

[Production Example 2]

441.9 parts by weight of distilled water and 3.0 parts by weight of sodium dibenzenesulfate were added to a four-necked flask equipped with a nitrogen inlet, a thermometer, a cooler, and an agitator, and the temperature of the reaction section was raised to 80 ° C. When 80 ° C. is maintained, nitrogen is injected for 5 minutes to make the reaction part nitrogen atmosphere, and then nitrogen is removed.

Next, 15.5 parts by weight, which is 10% of the monomer mixture described below, is added thereto, followed by adding 2.33 parts by weight of sodium persulfate, which is a radical polymerization initiator, and 40 parts by weight of distilled water solution.

After holding for 10 minutes, the remaining monomer mixture was injected for 90 minutes, aged for 1 hour, and the conversion ratio ^{* 1)} was measured to be 97% or more, and then cooled to 30 ° C. Filter off with a 400 mesh filter to remove the coagulum.

The prepared core emulsion had a solids content of 24.8 percent, a pH of 2.5 and a particle size ^{* 2)} of 40 nm.

[Manufacture example 3]

In Preparation Example 2, 0.23 parts by weight of bromotrichloromethane is mixed with the monomer to be used.

The prepared core emulsion had a solids content of 24.9 percent, a pH of 2.5 and a particle size ^{* 2)} of 41.5 nm.

[Production Example 4]

Four-necked flask equipped with nitrogen inlet, thermometer, cooler and stirrer octyl phenyl based with 803.3 parts by weight of distilled water, 0.78 parts by weight of sodium dibenzenesulfate and hydrophilic-lipophilic balance with 13-14 and 9-10 ethylene oxide repeaters 1.00 parts by weight of a nonionic emulsifier was charged and the temperature of the reaction portion was raised to 80 ° C. When 80 ° C is maintained, nitrogen is injected for 5 minutes, the reaction part is placed in a nitrogen atmosphere, and nitrogen is removed.

Next, 15.5 parts by weight, which is 10% of the monomer mixture described below, is added thereto, followed by adding 2.33 parts by weight of ammonium persulfate, which is a radical polymerization initiator, and 40 parts by weight of distilled water solution.

After holding for 10 minutes, a mixture of the remaining monomers and 0.78 parts by weight of N-dodecyl mercaptan was injected for 90 minutes, and after 1 hour of aging, the conversion ratio ^{* 1)} was specified and cooled to 30 ° C. if it was 97% or more. Filter off with a 400 mesh filter to remove the coagulum.

The prepared core emulsion had a solid content of 15.8 percent, a pH of 2.3, and a particle size ^{* 2)} of 37.6 nm.

Production Example 5

In the above preparation 23.3 parts by weight of methacrylic acid and 15.5 parts by weight of itaconic acid were mixed instead of 38.8 parts by weight of methacrylic acid, the solids content of the polymer was 15.9 percent and the pH was 2.65.

[Production of Similar Water Soluble-Emulsion Resin]

Example 1

A four-necked flask equipped with a nitrogen inlet, a thermometer, a cooler, and a stirrer was initially charged with 143.1 parts by weight of the core emulsion prepared in Preparation 1 and 195.0 parts by weight of distilled water, and the temperature of the reaction portion was raised to 80 ° C. When 80 ° C. is maintained, nitrogen is injected for 5 minutes to make the reaction part nitrogen atmosphere, and then nitrogen is removed.

Insert 2.7 parts by weight of ammonia and 22.8 parts by weight of distilled water for 30 minutes. After holding for 30 minutes, 1.78 parts by weight of sodium persulfate and 26.7 parts by weight of distilled water solution are added, and the following monomer mixture is added for 120 minutes.

After 90 minutes of holding, the conversion rate was measured to be 98% or more, and the reaction part was cooled to 45 ° C and the pH was adjusted to 9.0-9.5 with ammonia and distilled water mixture.

Filter off with a 200 mesh filter to remove the coagulum.

The prepared emulsion had a solids content of 43.3 weight percent, a pH of 9.10, a particle size of 121.3 nm, and a Din Cup # 4 viscosity of 25 ° C. at 16.2 seconds.

Example 2

In a four-necked flask equipped with a nitrogen inlet, a thermometer, a cooler and a stirrer, 122.2 parts by weight of the core emulsion prepared in Preparation 1 and 168.7 parts by weight of distilled water were initially charged, and the temperature of the reaction part was raised to 80 ° C. When 80 ° C is maintained, nitrogen is injected for 5 minutes, the reaction part is placed in a nitrogen atmosphere, and nitrogen is removed.

66.6 parts by weight of 1% NaOH aqueous solution is injected for 10 minutes. After holding for 20 minutes, 1.65 parts by weight of sodium persulfate and 26.7 parts by weight of distilled water solution are added, and the following monomer mixture is added for 120 minutes.

After 90 minutes of holding, the conversion rate was measured to be 98% or more, and the reaction part was cooled to 45 ° C. and the pH was adjusted to 9.0˜9.5 with a 20% NaOH aqueous solution and distilled water mixture.

Filter off with a 200 mesh filter to remove the coagulum.

The solids content of the prepared emulsion was 43.2 weight percent, pH was 9.23, particle size was 90 nm, and the Din Cup # 4 viscosity at 25 ° C. was 18.5 seconds.

Example 3

In a four-necked flask equipped with a nitrogen inlet, a thermometer, a cooler, and a stirrer, 122.2 parts by weight of the core emulsion prepared in Preparation Example 1 and 201.0 parts by weight of distilled water were initially charged, and the temperature of the reaction part was raised to 80 ° C. When 80 ° C is maintained, nitrogen is injected for 5 minutes, the reaction part is placed in a nitrogen atmosphere, and nitrogen is removed.

2.2 parts by weight of dimethylethanolamine and 22.8 parts by weight of distilled water are charged for 30 minutes. After holding for 30 minutes, 2.69 parts by weight of sodium persulfate and 26.7 parts by weight of distilled water solution are added, and the following monomer mixture is injected for 120 minutes.

After 90 minutes of holding, the conversion rate was measured to be 98% or more, and the reaction part was cooled to 45 ° C and the pH was adjusted to 9.0-9.5 with a mixture of dimethylethanolamine and distilled water.

The coagulum is removed by filtration with a 200 mesh filter.

The solids content of the prepared emulsion was 43.4 weight percent, pH was 9.05, particle size was 115.2 nm, and the viscosity of Din Cup # 4 at 25 ° C. was 13.4 seconds.

Example 4

In Example 2, 78.2 parts by weight of the core emulsion prepared in Preparation Example 2 and 201.4 parts by weight of distilled water were initially charged, and 78.1 parts by weight of a 1% NaOH aqueous solution was used. The prepared emulsion had a solid content of 43.4% and a pH of 9.36 at 25 ° C. and a Din Cup # 4 viscosity of 13.1 seconds.

Example 5

In Example 4, the core emulsion prepared in Preparation Example 3 was used. The prepared emulsion had a solid content of 43.4% and a pH of 9.27 at 25 ° C. and a Din Cup # 4 viscosity of 12.4 seconds.

Example 6

In Example 2, 122.2 parts by weight of the core emulsion prepared in Preparation Example 4 and 222.5 parts by weight of distilled water were initially charged, and 11.5 parts by weight of a 1% NaOH aqueous solution was used. The solid content of the emulsion thus prepared was 43.4%, the pH was 9.36, and the viscosity of Din Cup # 4 was 14.5 seconds at 25 ° C.

Example 7

In Example 6, the core emulsion prepared in Preparation Example 5 was used. The solid content of the emulsion thus prepared was 43.4%, the pH was 9.36, and the viscosity of Din Cup # 4 was 14.1 sec at 25 ° C.

Example 8

Example 6 is an example of an emulsion prepared using an oil-soluble initiator in place of sodium persulfate, which is a water-soluble initiator.

In a four-necked flask equipped with a nitrogen inlet, a thermometer, a cooler, and a stirrer, 122.2 parts by weight of the core emulsion prepared in Preparation Example 4 and 250.4 parts by weight of distilled water were initially charged, and the temperature of the reaction part was raised to 80 ° C. When 80 ° C is maintained, nitrogen is injected for 5 minutes, the reaction part is placed in a nitrogen atmosphere, and nitrogen is removed.

11.5 parts by weight of an aqueous 1% NaOH solution was injected for 10 minutes, and after holding for 20 minutes, 2.8 parts by weight of 2.2'-azobisisobutyronitrile, which is an oil-soluble initiator, was dissolved in the monomer mixture below and injected for 120 minutes.

After 90 minutes of holding, the conversion rate was measured to be 98% or more, and the reaction part was cooled to 45 ° C and the pH was adjusted to 9.0 to 9.5 with a 1% NaOH aqueous solution and distilled water mixture.

Filter off with a 200 mesh filter to remove the coagulum.

Solids of the prepared emulsion were 43.2 weight percent, pH was 9.05, and particle size was 80 nm.

Comparative Example 1

A. Preparation of Water Soluble Dispersions

Into a four-necked flask equipped with a nitrogen inlet, thermometer, cooler and stirrer, 91.8 parts by weight of isopropyl alcohol and 243.7 parts by weight of methyl ethyl ketone are initially charged and the reaction temperature is raised to 79-80 ° C.

When the solvent starts to reflux, 10.0 parts by weight of 2.2'-azobisisobutyronitrile, which is a radical initiator, is dissolved in the following monomer mixture while injecting nitrogen, and the mixture is injected for 120 minutes and maintained for 4 hours.

Cool the temperature of the reaction section to 45 ° C. and inject 61.9 parts by weight of dimethylethanolamine and hold for 30 minutes. Next, 1077.6 parts by weight of midstream was added thereto, and stirred for 30 minutes, and then a reduced pressure distillation apparatus was mounted in the cooler, followed by stirring at 300-400 mmHg pressure, 70-80 ° C. temperature, and 400-800 RPM for 1 hour to remove the solvent. .

The prepared water-soluble polymers had a refractive index of 1.332 to 1.334, a solid content of 26.5 weight percent, and a pH of 7.6.

B. Preparation of Water-Emulsion Resin

The 250.0 parts by weight of the water-soluble resin dispersion and 246.7 parts by weight of distilled water prepared above were initially charged in the reaction portion and heated to 80 ° C. 2.6 parts by weight of sodium persulfate and 50.0 parts by weight of distilled water were added and the following monomers were injected for 90 minutes and then maintained for 120 minutes.

Cooled to room temperature and filtered through a 400 mesh filter to remove the coagulum. Solid content of resin is 43.5%, pH is 7.5 and particle size is 125nm.

[Paint application comparison test]

Table 2 shows the optimized paint application formulation of the present invention, and the paint was prepared by applying the similar water-soluble emulsion resins prepared in Examples 1-8. In addition, the paint was prepared by applying the following paint formulation to the emulsion prepared in Comparative Example 1 and an existing emulsion resin containing a large amount of low molecular weight emulsifier.

In the production process, premixed distilled water, propylene glycol, dispersant, antifoaming agent, pH adjusting agent, texanol in the millbase step, and then adding titanium dioxide and stirring H.SD. (High Speed Dissolver) for 90 minutes. The particle size is less than 5 micrometers and the pH is 10.01.

In the finishing step, while slowly stirring, the resin and the antifoam are added sequentially, and after 10 minutes of stirring, the paint KU viscosity is adjusted to 80 to 85 KU at 25 ° C. with a thickener and water. Paint solids range from 45 to 46 percent by weight, paint pH from 9.0 to 9.2 and particle sizes less than 10 micrometers.

The physical properties of the paint prepared by applying the similar water-soluble emulsion resins prepared in Examples 1 to 8, the emulsion prepared in Comparative Example 1, and an existing emulsion resin containing a large amount of low molecular weight emulsifier are shown in Table 3 below. .

[Test Methods]

1) Seal the paint in tinken and leave at 50 ℃ for 120 hours, and the KU viscosity should not change ± 8KU.

2) Seal the paint in tinken and repeat it for 3 hours at -5 ℃ for 16 hours and 25 ℃ for 8 hours, and the KU viscosity should not change + 8KU.

3) Paint with a bird applicator so that the thickness of the wet film on the glass plate is 150 microns, and dry it for 24 hours at 25 ℃ / 55% constant temperature and humidity conditions and measure it with a gloss meter.

4) Paint twice with a brush so that the dry film thickness is 80 micrometers on the slate plate, dry for 72 hours, and mask the backside with liquid paraffin. After immersing in fresh water for 24 hours and taking out the film, the gloss holding ratio was measured after 2 hours.

5) Specimen preparation and measuring method is the same as 2) above, but immersed in aqueous calcium hydroxide solution.

Claims (23)

Neutralize the core one-step emulsion containing a sufficient amount of carboxylic acid groups prepared by the emulsion polymerization method with a neutralizing agent, wherein the appropriate neutralization degree of the core polymer is 5 to 75 percent with respect to the total amount of the carboxylic acid groups of the core polymer, Is 4.5 to 8.0, and the neutralized one-stage core emulsion is used as a polymer dispersant to prepare a stable secondary cell emulsion without the addition of an external low molecular weight emulsifier. Process for the preparation of two stage emulsion polymers. The method of claim 1, wherein the monomer containing a carboxylic acid group is neutralized with a neutralizing agent consisting of a base sufficient to serve as a polymer dispersion stabilizer in the cell emulsion preparation step of the polymerization step 2, the amount of the monomers total 100 A method for producing a two-stage emulsion polymer having a core-cell structure, characterized in that contained in 10 to 40 parts by weight with respect to parts by weight. The method of claim 1, wherein the monomer comprising a carboxylic acid is acrylic acid, methacrylic acid, vinyl benzene acid and isopentyl benzene acid and single carboxylic acid, crotonic acid, itaconic acid comprising two carboxylic acids A method for producing a two-stage emulsion polymer having a core-cell structure, characterized in that one or two or more are mixed and used from the group consisting of maleic acid, fmaric acid and acid anhydrides thereof. The monomer composition of the first stage core polymer is 0-50 parts by weight of alkyl or cycloalkyl acrylic acid or methacrylic acid ester having 1 to 18 carbon atoms, alkoxy alkyl acrylic acid or methacrylic acid based on 100 parts by weight of the total monomers. 0-5 parts by weight of ester, 0-10 parts by weight of hydroxy alkyl acrylic acid or methacrylic acid ester having 2 to 8 carbon atoms, 0-90 parts by weight of vinyl aromatic compound, 0-5 parts by weight of conjugated diene having 4 to 9 carbon atoms , Acrylonitrile, methacrylonitrile 0-30 parts by weight and a monomer comprising a carboxylic acid 10-40 parts by weight of a method for producing a two-stage emulsion polymer having a core-cell structure. The monomer according to claim 1, wherein the monomer having a vinyl group that can be polymerized by a radical includes alkyl or cycloalkyl acrylic acid or methacrylic ester having 1 to 18 carbon atoms, alkoxy alkyl acrylic acid or methacrylic acid ester, and having 2 to 8 carbon atoms. 2 having a core-cell structure, characterized in that it is selected from the group consisting of hydroxy alkyl acrylic or methacrylic acid esters, vinyl aromatic compounds, conjugated dienes having 4 to 9 carbon atoms, acrylonitrile, and methacrylonitrile. Process for preparing a step emulsion polymer. The method for preparing a two-stage emulsion polymer having a core-cell structure according to claim 1, wherein a chain conversion agent is used in an amount of 0.1 to 0.5 parts by weight based on 100 parts by weight of the core monomer to adjust the molecular weight of the core polymer. The method of claim 1, wherein the radical polymerization initiator is ammonium, potassium, sodium persulfate, cyclohexyl hydroperoxide, cumene hydroperoxide, n-octyl hydroperoxide, t, wherein radicals are produced by thermal dissociation at high temperatures. Use of 0.2 to 1.5 parts by weight of a water-soluble thermal dissociation initiator such as -butyl hydroperoxide, sec-butyl hydroperoxide and 1-phenyl-2-methylpropyl 1-hydroperoxide by 100 parts by weight of the core monomer A process for producing a two-stage emulsion polymer having a core-cell structure. According to claim 1, In order to accelerate the polymerization rate and impart stability of the core emulsion, anionic or nonionic emulsifiers are used alone or mixed with each other, the amount is 0.2 to 2.0 parts by weight based on 100 parts by weight of monomers, Method for producing a two-stage emulsion polymer having a core-cell structure, characterized in that 0 to 1.0 parts by weight for non-ions. The method of claim 1, the core emulsion polymerization method is a two-step emulsification having a core-cell structure according to the process of the initial injection of the water and emulsifier of the continuous phase, the injection of the initiator and monomer, the reaction temperature is 75 ~ 80 ℃ Method of Making Polymers. The neutralizing agent according to claim 1, wherein the neutralizing agent used to neutralize the core polymer includes primary bases such as inorganic bases such as ammonia, NaOH, KOH, LiOH and organic bases such as dimethylethanolamine, AMP 95 (manufactured by Angus) and trityl amine; A method for producing a two-stage emulsion polymer having a core-cell structure, characterized in that it is selected from secondary and tertiary amines. The method of claim 1, wherein the monomer in preparing the two-stage cell polymer is a monomer comprising carboxylic acid, alkyl having 1 to 18 carbon atoms or cycloalkyl acrylic acid or methacrylic acid ester, alkoxy alkyl acrylic acid or methacrylic acid ester Hydroxy alkyl acrylic acid or methacrylic acid ester having 2 to 8 carbon atoms, vinyl aromatic compound, conjugate diene having 4 to 9 carbon atoms, acrylonitrile and methacrylonitrile selected from one or two and mixed, The monomer composition is a monomer containing 0 to 8 parts by weight of carboxylic acid, 1 to 70 parts by weight of alkyl or cycloalkyl acrylic acid or methacrylic acid ester having 1 to 18 carbon atoms, and 0 to 5 parts by weight with respect to 100 parts by weight of the monomer. Alkoxy alkyl acrylic acid or methacrylic acid ester, 0-15 parts by weight of hydroxy alkyl acrylic Acids or methacrylic acid esters, 12-88 parts by weight of vinyl aromatic compounds, 0-5 parts by weight of conjugate dienes having 4 to 9 carbon atoms, and 0-30 parts by weight of acrylonitrile and methacrylonitrile. Method for producing a two-stage emulsion polymer having a cell structure. The method of claim 1, wherein the initiator in preparing the two-stage cell polymer is a water-soluble initiator consisting of an alkali metal or ammonium persulfate and an oil-soluble initiator, the amount of use is 0.1 to 100 parts by weight of the monomer used in the two-stage polymerization Process for producing a two-stage emulsion polymer having a core-cell structure, characterized in that 1.5 parts by weight. 13. The oil-soluble initiator of claim 12, wherein the oil-soluble initiator is a dialkyl peroxide such as t-butyl benzoperoxide and 2,2'-azobisisobutyronitrile, 2,2'-azobismethylbutyronitrile, 1,1 ' -Azo compound such as azobis1-cyclohexane carbonitrile. A process for producing a two-stage emulsion polymer having a core-cell structure. The two-step emulsion having a core-cell structure according to claim 1, wherein the ratio of the first-stage core polymer and the two-stage polymerized monomer is 1: 4 to 1:20, and more preferably 1: 10.5 to 1:15. Method of Making Polymers. According to claim 1, The two-step emulsion polymerization method according to the process of injecting the initiator and monomer after the initial injection of water and neutralized core emulsion, 2, having a core-cell structure, characterized in that the polymerization temperature is 75 ~ 84 ℃ Step of preparing a polymer. The reaction phase according to claim 1, wherein the reaction phase 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 agent for coating film formation in coating applications. Method for producing a two-stage emulsion polymer having a core-cell structure, characterized in that used in 0 to 200 parts by weight based on 100 parts by weight. The coating composition containing the resin solid content 15-30 weight part with respect to 100 weight part of paints the emulsion polymer containing the minimum amount of low molecular weight emulsifiers of Claim 1. The coating composition according to claim 17, wherein an additive such as a pigment, an antifreeze, an antifoaming agent, a pH adjusting agent, a cosolvent, a dispersant, and the like are blended into the mill base. The method of claim 18, wherein the pigment is used in the white paint of various grades of titanium dioxide alone, and in the case of colored paint, red iron oxide, yellow iron oxide alone or a mixture of titanium dioxide and an organic pigment, in the case of a white paint pigment The amount of the coating composition, characterized in that the pigment volume percent (PVC) is used to 10 to 30. The antifoaming agent according to claim 18, wherein the antifoaming agent of siloxane is divided into the same amount at the mill base and the finishing step, but the total amount is 0.05 ~ 0.5 parts by weight based on 100 parts by weight of paint. The coating composition according to claim 18, wherein the pH adjusting agent uses AMP 95 (manufactured by Angus), ammonia, dimethethanolamine, and 0.1 to 0.2 parts by weight based on 100 parts by weight of the paint. 19. The method of claim 18, in order to prevent the flow of the coating composition and smooth coating, a nonionic polyurethane-based thickening agent is used alone or in combination with an ASE-based thickening agent, and the amount of the polyurethane-based thickening agent is used alone. When used, 0.5 to 2.5 parts by weight is used per 100 parts by weight of paint, and when used in combination with ASE, polyurethane is used by 0.2 to 1.0 parts by weight and 0.5 to 1.0 parts by weight for ASE based on 100 parts by weight of paint. Coating composition. The coating composition according to claim 18, wherein the coating agent for forming a coating film uses a high boiling point solvent, the amount of which is 5 to 10 parts by weight based on 100 parts by weight of the resin solids used.