JPH07216005A - Aqueous emulsion composition and its production - Google Patents

Abstract

PURPOSE:To form a film having high water resistance, adhesion to substrates, surface smoothness and transparency from an aqueous emulsion composition simply by drying. CONSTITUTION:This composition is obtained by carrying out the emulsion copolymerization of a polymerizable composition containing polymerizable unsaturated monomers and a plasticizer in the presence of a reactive emulsifying agent in an aqueous medium containing a hydrophilic organic solvent. The polymerizable unsaturated monomers can be constituted of such monomers capable of forming a polymer having 10-65 deg.C glass transition temperature (Tg) e.g. (A) 25-90wt.% rigid monomer capable of forming a polymer having >=50 deg.C Tg, (B) 10-70 wt.% soft monomer capable of forming a polymer having <=25 deg.C T. and (C) 0.1-10wt.% unsaturated monomer having carboxyl group. The amounts of the components based on 100 pts. wt. monomers are l-20 pts.wt. plasticizer, 1-60 pts.wt. hydrophilic organic solvent and 0.1-10 pts.wt. reactive emulsifying agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous emulsion composition which can be used as a coating agent, an adhesive agent, a fiber processing agent, an adhesive agent for a substrate such as wood, metal, paper, plastic, slate and the like, and a method for producing the same. .

[0002]

BACKGROUND OF THE INVENTION Aqueous resin dispersions are excellent in non-pollution, resource saving and workability, unlike solvent type. Therefore, the aqueous resin dispersion liquid is widely used as a coating agent for paints, an adhesive, a fiber processing agent, an adhesive, and the like. However, the polymer of the aqueous resin dispersion is present in the form of particles and has a high molecular weight of generally 500,000 to 1,000,000. Therefore, not only the permeability to the base material and the adhesion to the base material are small, but also the film forming property is inferior to that of the resin solution, and it is difficult to obtain a smooth coating film.

In order to solve these problems, it has been proposed to add a water-soluble resin to a microemulsion or an aqueous resin dispersion having a small particle size. However, in order to reduce the particle size of the polymer, a large amount of emulsifier is generally required, and therefore the emulsifier reduces the water resistance of the coating and the adhesion to the substrate. In addition, addition of a water-soluble resin also reduces the water resistance of the coating, and is not suitable for practical use.

In order to improve water resistance, it has been proposed to use a radically polymerizable reactive emulsifier in place of a non-reactive emulsifier such as an anionic surfactant or a nonionic surfactant. However, an aqueous emulsion obtained by emulsion polymerization using a reactive emulsifier is still insufficient in water resistance and adhesion to a substrate, and the surface smoothness and transparency of the coating are likely to be lowered.

Further, a crosslinkable aqueous resin composition has been proposed. For example, in JP-A-63-284280, a zinc ammonium carbonate aqueous solution or a zirconyl ammonium carbonate aqueous solution is added to a styrene-acrylic copolymer emulsion or (meth) acrylic polymer emulsion having a carboxyl group introduced, Adhesives having a pH of 6.8 or higher have been proposed. Further, in JP-A-5-105799, dispersed particles of an emulsion are composed of a phase of a copolymer having an epoxy group introduced therein and a phase of a copolymer having a carboxyl group introduced therein, and a specific amount based on the epoxy group. Emulsion compositions containing the sulphonic ions of are disclosed. However, these compositions are cross-linking compositions.
Therefore, if the reactivity is increased to improve the water resistance, the pot life becomes shorter, and if the reactivity is decreased to increase the stability, a highly water resistant coating film cannot be formed at room temperature, and after heat treatment, etc. Processing is required.

[0006]

Therefore, an object of the present invention is to provide an aqueous emulsion composition capable of forming a coating excellent in water resistance and adhesion to a substrate by simply drying without taking any special means. There is in providing the manufacturing method.

Another object of the present invention is to provide an aqueous emulsion composition capable of forming a film having excellent surface smoothness and transparency and a method for producing the same.

[0008]

MEANS FOR SOLVING THE PROBLEMS The present inventors have found that when emulsion polymerization is carried out in a system containing a plasticizer and / or a hydrophilic organic solvent, the polymerization stability decreases, and when emulsion polymerization is carried out in the presence of a reactive emulsifier, Although the polymerization stability was improved, it was found that the water resistance, the adhesion to the substrate, and the surface smoothness of the coating film were still insufficient, probably because the film-forming property was deteriorated. As a result of further investigation based on these findings, when the polymerizable monomer is emulsion polymerized in a system in which a plasticizer, a hydrophilic organic solvent and a reactive emulsifier are combined, the plasticizer is efficiently and stably incorporated in the polymer particles. It was found that the water resistance, the adhesion to the substrate, or the like can be remarkably improved due to the permeation or diffusion, and the present invention has been completed.

That is, the present invention is obtained by polymerizing a polymerizable composition containing a polymerizable unsaturated monomer and a plasticizer in an aqueous medium in the presence of a hydrophilic organic solvent and a reactive emulsifier. Aqueous emulsion composition.

The polymerizable unsaturated monomer may be composed of an unsaturated monomer within a range that forms a polymer at a suitable glass transition temperature, for example, about 10 to 65 ° C. The plurality of unsaturated monomers are (A) at least one hard monomer forming a polymer having a glass transition temperature of 50 ° C. or higher, and (B) at least one soft monomer forming a polymer having a glass transition temperature of 25 ° C. or lower. It may be composed of a monomer, (C) a monomer having a carboxyl group or a salt thereof, and the like. The ratio of these monomers can be appropriately selected, and for example, (A) hard monomer 2
5 to 90% by weight, (B) 10 to 70% by weight of the soft monomer,
And (C) a monomer having a carboxyl group or a salt thereof can be appropriately selected within a range of about 0.1 to 10% by weight.

The ratio of the plasticizer is, for example, about 1 to 20 parts by weight, and the ratio of the hydrophilic organic solvent is, for example, about 5 to 60 parts by weight, based on 100 parts by weight of the total amount of the polymerizable unsaturated monomer. The proportion of the reactive emulsifier can be appropriately selected from the range of, for example, about 0.1 to 10 parts by weight. The content of the (E) hydrophilic organic solvent in the aqueous medium can be selected within a range that does not impair emulsion polymerization stability, for example, within a range of about 1 to 30 parts by weight relative to 100 parts by weight of water.

In the method of the present invention, a polymerizable composition containing a polymerizable unsaturated monomer and a plasticizer is emulsion-polymerized in an aqueous medium in the presence of a hydrophilic organic solvent and a reactive emulsifier to obtain an aqueous solution. An emulsion composition is produced.

In the following, acrylic monomers and methacrylic monomers are collectively referred to as (meth) acrylic monomers unless otherwise specified. Further, the “glass transition temperature” means a value calculated by the following Tobolsky calculation formula.

1 / Tg = Wa / Tga + Wb / Tgb + ... [wherein Tg is the glass transition temperature (° K) of the copolymer, T
ga is the glass transition temperature (° K) of the homopolymer of monomer a, Tgb is the glass transition temperature (° K) of the homopolymer of monomer b, Wa is the weight fraction of monomer a, and Wb is the single Quantity b
Of the polymerizable unsaturated monomer,
(M) An acrylic monomer, a styrene monomer, a vinyl ester, a monomer having a functional group, and other monomers are included. As these polymerizable monomers, one or more monomers of the same or different series can be used.

Examples of (meth) acrylic monomers include:
An alkyl group having about 1 to 20 carbon atoms, a cycloalkyl group,
A (meth) acrylate having an aryl group or an aralkyl group is included. More specifically, examples of the (meth) acrylic monomer include methyl (meth) acrylate,
Ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (ta) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n- Amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, n-heptyl (meth) acrylate, isoheptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) Alkyl (meth) acrylates such as acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate; cyclohexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acryl Such as theft and the like.
These (meth) acrylic monomers can be used alone or in combination of two or more.

Among the (meth) acrylic monomers, a (meth) acrylate having a linear or branched alkyl group having 1 to 12 carbon atoms, particularly about 1 to 10 carbon atoms is preferable.

The styrene-based monomer includes, for example, styrene, α-methylstyrene, p-methylstyrene, vinyltoluene and the like. The preferred styrenic monomer includes styrene. Examples of the vinyl ester include vinyl acetate, vinyl caproate, vinyl propionate, vinyl versatate (VeoVa, etc.) and the like. Styrene-based monomers and vinyl esters may be used alone or in combination of two or more.

As the monomer having a functional group, an α, β-ethylenically unsaturated compound having a hydroxyl group, for example, 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate and the like; α, β-ethylenically unsaturated compound having a glycidyl group, such as glycidyl (meth) acrylate, etc .; Unsaturated compound having a methylol group, such as N-methylol (meth) acrylamide and the like; Acidic monomers such as α,
β-ethylenically unsaturated carboxylic acids (for example, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, unsaturated polycarboxylic acids such as itaconic acid, maleic acid, fumaric acid and maleic anhydride, itaconic acid Monoesters such as monoesters of unsaturated polyvalent carboxylic acids such as monoesters, maleic acid monoesters, fumaric acid monoesters and the like), α, β-ethylenically unsaturated sulfonic acids (eg sodium styrene sulfonate) , Sodium vinyl sulfonate, etc.) and the like. Monomers having these functional groups may be used alone or in combination of two or more.

Examples of other monomers include fumaric acid esters and maleic acid esters corresponding to these (eg, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, di (2-ethylhexyl) fumarate), (Meth) acrylonitrile, vinyl chloride, vinylidene chloride, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, diacetone (Meth) acrylamide etc. are mentioned. Other monomers may be used alone or in combination of two or more.

Preferred aqueous resin emulsions include, for example, (1) a (meth) acrylic emulsion containing a (meth) acrylic monomer as a main component (for example, a (meth) acrylic monomer alone or as a copolymer). Coalesce, emulsion containing (meth) acrylic resin such as (meth) acrylic-styrene copolymer), (2) styrene emulsion containing styrene monomer as main component (for example, styrene- (meth) acrylic copolymer) (Emulsion containing styrene resin such as polymer), (3) Vinyl acetate emulsion containing vinyl acetate as a main component (for example, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl acetate- (meth) acrylic copolymer) And a vinyl acetate-based resin such as a vinyl acetate-VeoVa copolymer).

More preferred aqueous resin emulsions include (meth) acrylic emulsions, (meth) acrylic-styrene emulsions, and styrene- (meth) acrylic emulsions.

When the (meth) acrylic, (meth) acrylic-styrene or styrene- (meth) acrylic emulsion is constituted, the polymerizable unsaturated monomer has a glass transition temperature of 10 to 65 ° C., preferably Is 15 to 50 ° C,
More preferably, it is composed of an unsaturated monomer forming a homopolymer or a copolymer at about 20 to 40 ° C., particularly a plurality of unsaturated monomers forming a copolymer having the above glass transition temperature. .

When the polymerizable unsaturated monomer is composed of a plurality of unsaturated monomers, (A) the glass transition temperature is 50 ° C. or higher, preferably 60 to 120 ° C., more preferably 70 to 11
At least one hard monomer forming a hard polymer at about 0 ° C., and (B) glass transition temperature of 25 ° C. or lower, preferably −100 ° C. to 0 ° C., more preferably −10 to −1.
It is preferred to combine with at least one soft monomer forming a soft polymer at around 00 ° C.

The hard monomer has, for example, 1 to 1 carbon atoms.
Alkyl methacrylate of about 6 (for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, methacrylic acid t
-Butyl etc.), styrene, acrylonitrile and the like. Preferred hard monomers include methyl methacrylate, ethyl methacrylate, styrene, acrylonitrile. The soft monomer has, for example, 1 to 1 carbon atoms.
Acrylic acid ester having about 12 alkyl groups and methacrylic acid ester having alkyl group having about 4 to 12 carbon atoms (for example, ethyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, n-methacrylate) -Hexyl, lauryl methacrylate, etc.) and the like. A preferred soft monomer includes an acrylate ester having an alkyl group having about 2 to 10 carbon atoms.

The preferred polymerizable unsaturated monomer is adhesiveness,
In order to enhance the stability of the emulsion, in addition to the hard monomer component and the soft monomer component, an acidic monomer, preferably an unsaturated monomer having a carboxyl group or a salt thereof, particularly an α, β-ethylenic monomer is used. It contains a saturated monocarboxylic acid or a salt thereof. Preferred α, β-ethylenically unsaturated monocarboxylic acids include (meth) acrylic acid, especially acrylic acid.

A preferred monomer combination is a hard monomer selected from methacrylic acid alkyl ester, styrene monomer, and (meth) acrylonitrile (eg, methyl methacrylate, styrene, acrylonitrile, etc.).
And a soft monomer (for example, an acrylic acid ester having an alkyl group having about 2 to 10 carbon atoms) selected from an acrylic acid alkyl ester, and α, β-ethylenically unsaturated such as acrylic acid or methacrylic acid. Combinations with carboxylic acids are included. The stability of the emulsion can be further enhanced by neutralizing the carboxyl group of the α, β-ethylenically unsaturated carboxylic acid with a basic substance such as ammonia or amines.

The proportions of (A) hard monomer, (B) soft monomer and (C) unsaturated monomer having a carboxyl group or a salt thereof are within a range capable of forming a copolymer having the above glass transition temperature. Can be appropriately selected within, for example, (A) hard monomer 25 to 90% by weight, preferably 30 to 80% by weight, more preferably 40 to 80% by weight, (B) soft monomer 10 to 70. %, Preferably 15 to 50% by weight, more preferably about 20 to 50% by weight, and (C) an unsaturated monomer having a carboxyl group or a salt thereof (0.1 to 0.1).
It is 0% by weight, preferably 1 to 7% by weight, more preferably 2 to 5% by weight. If the amount of the hard monomer (A) used is less than 25% by weight, the smoothness and glossiness of the coating film will deteriorate, and if it exceeds 90% by weight, the water resistance will easily decrease. Further, if the amount of the soft monomer (B) is less than 10% by weight, the water resistance of the coating film is lowered, and if it exceeds 70% by weight, the adhesion to the substrate is easily lowered. Moreover, when the amount of the unsaturated monomer (C) is out of the above range, the polymerization stability may decrease.

The plasticizer (D) includes phthalic acid plasticizers, fatty acid plasticizers, polyester plasticizers, phosphoric acid plasticizers, epoxy plasticizers and the like. These plasticizers may be used either individually or in combination of two or more.

Examples of the phthalic acid type plasticizer include, for example, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dihexyl phthalate, diheptyl phthalate, di n-octyl phthalate, di2-ethylhexyl phthalate, butyl lauryl phthalate. ,, dinonyl phthalate, didecyl phthalate, ditridecyl phthalate, butylbenzyl phthalate, burtiphthalyl butyl glycolate, etc., having an alkyl group having about 1 to 14 carbon atoms (preferably 2 to 12, more preferably about 4 to 12 alkyl). A phthalate ester having a group).

Examples of the fatty acid plasticizer include adipic acid derivatives such as tributyl citrate, dioctyl adipate and diisodecyl adipate, azelaic acid derivatives such as dioctyl azelate, and sebacic acid derivatives such as dibutyl sebacate and dioctyl sebacate. An alkyl ester of a polycarboxylic acid having about 2 to 12 carbon atoms and the like are included. Polyester plasticizers include low molecular weight to high molecular weight plasticizers. Phosphoric acid plasticizers include tricresyl phosphate, trioctyl phosphate, and the like, and epoxy plasticizers include alkyl epoxy stearate, epoxidized soybean oil, diisodecyl 4,5 epoxytetrahydrophthalate, and the like.

[0031] Preferred plasticizers include those not inactive or adversely affecting the reaction, for example, phthalic acid plasticizers,
Particularly, a phthalic acid ester having a linear or branched alkyl group having about 4 to 12 carbon atoms is included.

The amount of the plasticizer can be appropriately selected according to the type of the plasticizer, the glass transition temperature of the polymer, etc. within a range that does not impair the polymerization stability, the water resistance of the coating, and the like. The amount is 1 to 20 parts by weight, preferably 2 to 17 parts by weight, and more preferably 5 to 15 parts by weight, relative to 100 parts by weight of the saturated monomer. If the amount of the plasticizer (D) is less than 1 part by weight with respect to 100 parts by weight of the polymerizable unsaturated monomer, the adhesion to the base material is deteriorated, and if it exceeds 20 parts by weight, the polymerization stability is deteriorated and coarse. Particles are easily generated.

The polymerizable composition containing the polymerizable monomer and the plasticizer undergoes emulsion polymerization in an aqueous medium in the coexistence of the hydrophilic organic solvent (E). If emulsion polymerization is carried out in the coexistence of such a hydrophilic organic solvent (E), the plasticizer (D) can efficiently permeate and diffuse into the polymer particles. it can. The hydrophilic organic solvent may be contained in the polymerizable unsaturated monomer containing the plasticizer or may be contained in the aqueous medium. Emulsion polymerization is often carried out usually in an aqueous medium containing a hydrophilic organic solvent.

The hydrophilic organic solvent (E) is a water-soluble solvent,
Examples thereof include alcohols, ketones such as acetone, ethers such as dioxane and tetrahydrofuran, cellosolves, carbitols, acetonitrile, aprotic polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide. These hydrophilic organic solvents may be used alone or in combination of two or more.

As alcohols, monohydric alcohols having 1 to 4 carbon atoms (for example, methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and t-butyl alcohol); dihydric alcohols (For example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, etc.); and polyhydric alcohols (eg, glycerin, etc.) and the like.

The cellosolves include, for example, methyl cellosolve (ethylene glycol monomethyl ether), ethyl cellosolve, propyl cellosolve, isopropyl cellosolve, butyl cellosolve, isobutyl cellosolve, isoamyl cellosolve, phenyl cellosolve, benzyl cellosolve, etc. Is, for example,
Diethylene glycol monomethyl ether, carbitol (diethylene glycol monoethyl ether), diethylene glycol monopropyl ether, diethylene glycol monobutyl ether and the like are included.

Preferred hydrophilic organic solvents include solvents that do not adversely affect polymerization stability and reaction, for example, water-soluble solvents having an alcoholic hydroxyl group (monohydric alcohols, cellosolves, carbitols, etc.). Be done. The solubility parameter SP of the hydrophilic organic solvent is, for example, 8.5 to 15.0, preferably 9 to 14, and more preferably 9.5 to 13. Such hydrophilic organic solvents include, for example, monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol and butanol, cellosolves and carbitols.

The solubility parameter SP is, for example,
JH Hildebrand, RL Scott; “Solubility of Non
-electrolytes ”Chap. 20, Rein hold (1950) can be calculated according to the following formula.

SP = (E / V) ^0.5 [where E is the heat of molar evaporation (cal) and V is the molecular volume (c)
c) is represented. The value of the solubility parameter SP of the solvent is, for example, H. Burr
ell; Off. Dig., 29 , 1069 (1957) can be referred to.

The amount of the hydrophilic organic solvent can be selected within a range that does not impair the polymerization stability, the water resistance of the coating, and the like. For example, 1 to 60 parts by weight relative to 100 parts by weight of the polymerizable unsaturated monomer,
Preferably 5 to 50 parts by weight, more preferably 10 to 50
It is about part by weight (for example, 15 to 45 parts by weight). When the hydrophilic organic solvent (E) is used in such a range, the plasticizer (D) can be efficiently and stably impregnated, penetrated or diffused into the emulsion particles, probably because of the water resistance of the coating and the adhesion to the substrate. Sexuality is greatly improved.

The content of the (E) hydrophilic organic solvent in the aqueous medium can be selected within a range that does not impair the polymerization stability and the like. For example, 1 to 40 parts by weight, preferably 100 parts by weight of water is preferable. The amount is 5 to 35 parts by weight, more preferably 10 to 30 parts by weight.

The aqueous emulsion composition of the present invention comprises a polymerizable composition containing the polymerizable unsaturated monomer and the plasticizer in the presence of a hydrophilic organic solvent and a reactive emulsifier (F) in an aqueous medium. Obtained by polymerizing. Examples of the reactive emulsifier (F) include radically polymerizable α, β-
Any reactive emulsifying agent may be used as long as it has an ethylenically unsaturated group and surface-active ability. The reactive emulsifier is
Usually, it has an α, β-ethylenically unsaturated group such as a vinyl group, an allyl group, or a (meth) acryloyl group, and an ionically dissociable group such as a sulfonyl group or a salt thereof or a hydrophilic group such as an alkyleneoxy group. In many cases, it may constitute an anionic or nonionic surfactant. The reactive emulsifier includes, for example, compounds represented by the following general formulas (1) to (4).

[0043]

[Chemical 1]

[0044]

[Chemical 2] In the general formulas (1) and (2), R ₁ represents a hydrocarbon group which may have a substituent (for example, a linear or branched alkyl group having 4 to 18 carbon atoms, or 4 to 18 carbon atoms). Alkenyl group or aralkyl group such as benzyl), R ₂ represents a hydrogen atom or a methyl group, and M represents an organic base or an inorganic base (for example, an alkali metal, NH ₄ residue, an amine residue or an alkanolamine residue). Show.

[0045]

[Chemical 3] (In the formula, R _1a represents a hydrocarbon group which may have a substituent (for example, an alkyl group having 4 to 18 carbon atoms and a carbon number of 4 to 1).
8 alkenyl group or aralkyl group such as benzyl), and R _1b represents a hydrogen atom or a hydrocarbon group which may have a substituent (eg, an alkyl group having 4 to 18 carbon atoms, a hydrocarbon group having 4 to 18 carbon atoms). An alkenyl group or an aralkyl group such as benzyl), R ₂ represents a hydrogen atom or a methyl group,
A represents an alkylene group having 2 to 4 carbon atoms, and n is 2 to 20
An integer of 0, M represents an organic base or an inorganic base (for example, alkali metal, NH ₄ residue, amine residue or alkanolamine residue).

[0046]

[Chemical 4] (In the formula, R ₁ is a hydrocarbon group which may have a substituent (for example, an alkyl group having 8 to 24 carbon atoms, 8 to 2 carbon atoms)
4 represents an alkenyl group, an aryl group such as phenyl, an aralkyl group such as benzyl) or an acyl group, and R ₂ represents a hydrogen atom or a methyl group. X represents a hydrogen atom, a nonionic or an anionic hydrophilic group, A represents an alkylene group having 2 to 4 carbon atoms, and n is an integer of 0 to 100.) The amount of the reactive emulsifier is polymerization stability and coarse particles. Can be selected within a range that does not impair the generation of water, the mechanical and chemical stability of the emulsion, and the water resistance of the coating. For example, 0.1 to 10 parts by weight relative to 100 parts by weight of the polymerizable unsaturated monomer. The amount is preferably 0.5 to 7.5 parts by weight, more preferably 1 to 7 parts by weight (for example, 2 to 7 parts by weight).
If the amount of the reactive emulsifier is less than 0.1 parts by weight relative to 100 parts by weight of the polymerizable unsaturated monomer, the polymerization stability, mechanical or chemical stability may be impaired, and 10 parts by weight may be used. If it exceeds, the water resistance of the coating and the adhesion to the substrate may decrease.

The average molecular weight of the polymer contained in the aqueous emulsion is, for example, about 5 × 10 ⁴ to 50 × 10 ⁴ ,
It is preferably about 8 × 10 ⁴ to 30 × 10 ⁴ . In the aqueous emulsion, the average particle size of the polymer particles is
It can be selected within a range that does not impair dispersion stability, adhesion, etc., and is, for example, 0.01 to 5 μm, preferably 0.05 to 2 μm.
m, and more preferably about 0.1 to 1 μm.

Furthermore, the polymer particles may be homogeneous or may have a heterophasic structure (eg core / shell structure, microdomain structure, etc.). Further, the shape of the polymer particles may be spherical, or may be an irregular shape such as sucrose.

The film-forming temperature of the aqueous emulsion composition varies depending on the glass transition temperature of the polymer, the amount of the plasticizer, the additives, etc., but it is usually 0 to 50 ° C., preferably 10 to 4
The temperature is 0 ° C, more preferably about 15 to 35 ° C. The solid content (ineffective content) of the aqueous emulsion composition is not particularly limited and may be, for example, about 30 to 60% by weight.

The aqueous emulsion composition of the present invention comprises a polymerizable composition containing the polymerizable unsaturated monomer and a plasticizer,
It can be produced by emulsion polymerization in the presence of a hydrophilic organic solvent and a reactive emulsifier in an aqueous medium.

The emulsion polymerization can be carried out using a polymerization initiator. As the polymerization initiator, potassium persulfate, sodium persulfate, persulfate such as ammonium persulfate,
A water-soluble polymerization initiator such as hydrogen peroxide can be used. The polymerization initiator may constitute a water-soluble redox type polymerization initiator system.

In order to adjust the molecular weight of the polymer, various chain transfer agents, for example, alcohols such as catechols, thiols and mercaptans may be used.
The amount of the chain transfer agent used is, for example, about 0.01 to 3 parts by weight, preferably about 0.05 to 2.5 parts by weight, based on 100 parts by weight of the total amount of the polymerizable unsaturated monomer.

In the emulsion polymerization, a surfactant such as an anionic surfactant or a nonionic surfactant may be used, if necessary, as long as the water resistance of the coating is not impaired.
You may use together protective colloids, such as polyvinyl alcohol and a water-soluble polymer.

The polymerization method can be carried out in accordance with a conventional emulsion polymerization method. For example, a method in which a polymerizable unsaturated monomer containing a plasticizer is charged at once and polymerized, a polymerizable unsaturated monomer is used. Continuously or intermittently, a polymerizable unsaturated monomer and at least one component of a hydrophilic organic solvent, a reactive emulsifier and a polymerization initiator are continuously or intermittently supplied. While polymerizing, etc. Further, in the case of continuously supplying, a method of polymerizing while dropping a polymerizable unsaturated monomer, a pre-emulsion method of preliminarily emulsifying and polymerizing a monomer, a method of combining the above methods, etc. Can be adopted. In addition, in emulsion polymerization, a conventional method such as a multistage polymerization method or a seed polymerization method can be employed. In these methods, the polymerizable composition containing the polymerizable monomer and the plasticizer may contain at least a part of the hydrophilic organic solvent, and may be subjected to the polymerization.

The polymerization reaction can be selected according to the kind of the polymerization initiator and is usually 40 to 100 ° C., preferably 50 to 90.
C., more preferably about 60 to 85.degree. C., and the reaction time is usually 1 to 12 hours (for example, 3 to
It is about 10 hours).

When an acidic monomer is used, if a basic substance is added to adjust the pH at an appropriate stage from the start to the end of emulsion polymerization or after the end of emulsification, the emulsion polymerization stability, freeze stability and mechanical stability are improved. It is possible to improve stability, chemical stability and the like. PH of emulsion is 5
As described above, it is often 6 to 9, more preferably 7 to 9 and often neutral or anionic (alkaline). Examples of the basic substance include organic bases (eg, amines such as ethylamine, diethylamine, triethylamine, alkolinamines such as morpholine, ethanolamine, diethylethanolamine, triethanolamine, morpholine); inorganic bases (eg, ammonia, water) Sodium oxide, potassium hydroxide, etc.) can be used.

When the aqueous emulsion composition is used, various additives such as a film forming aid, a dispersant such as a surfactant, an emulsifier, a surface conditioner, a preservative, etc.
Defoaming agents, coloring pigments, extender pigments, fillers, thickeners, organic solvents (for example, alcohols such as ethanol and isopropanol, cellosolves, carbitols, aliphatic, alicyclic or aromatic hydrocarbons, acetic acid Esters such as ethyl, ketones such as acetone and methyl ethyl ketone, ethers and the like) may be added.

[0058]

According to the aqueous emulsion composition and the method for producing the same of the present invention, a mixture of a polymerizable unsaturated monomer and a plasticizer is polymerized in the presence of a hydrophilic organic solvent and a reactive emulsifier. Therefore, only by drying, it is possible to form a film having excellent water resistance and adhesion to a substrate. It can also form a film with high surface smoothness, gloss and transparency.

R

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples.

Example 1 In a reactor (2 liter flask) equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inflow tube, 870 parts by weight of deionized water and a reactive emulsifier represented by the following formula (Aqualon HS -10, 25 parts by weight of Dai-ichi Kogyo Seiyaku Co., Ltd. was charged.

[0061]

[Chemical 5] After replacing the inside of the container with nitrogen gas, 150 parts by weight of isopropyl alcohol was added and heated to 80 ° C., 320 parts by weight of methyl methacrylate, 120 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of acrylic acid and 40 parts of dihexyl phthalate. A mixture of 30 parts by weight of a 5% aqueous potassium persulfate solution was added dropwise in parallel to the reactor over a period of 1 hour. After the dropwise addition was completed, heating was continued for another 2 hours, then cooled to room temperature, and neutralized by adding 5 parts by weight of 25% aqueous ammonia to obtain an aqueous emulsion composition.

Example 2 Emulsion polymerization was carried out in the same manner as in Example 1 except that 150 parts by weight of n-butyl acrylate was used instead of 120 parts by weight of 2-ethylhexyl acrylate to obtain an aqueous emulsion composition.

Example 3 Methyl methacrylate 260 was used as the polymerizable unsaturated monomer.
Parts by weight, 20 parts by weight of styrene, isobutyl acrylate 2
Emulsion polymerization was carried out in the same manner as in Example 1 except that 20 parts by weight and 20 parts by weight of acrylic acid were used to obtain an aqueous emulsion composition.

Example 4 Example 1 was repeated except that the reactive emulsifier used in Example 1 was replaced with 25 parts by weight of a reactive emulsifier represented by the following formula (Latherm S-180A, manufactured by Kao Corporation). Emulsion polymerization was carried out in the same manner to obtain an aqueous emulsion composition.

[0065]

[Chemical 6] Example 5 In the same manner as in Example 1 except that the reactive emulsifier used in Example 1 was replaced with 25 parts by weight of a reactive emulsifier represented by the following formula (Eleminol JS-2, manufactured by Sanyo Chemical Industry Co., Ltd.). Emulsion polymerization was carried out to obtain an aqueous emulsion composition.

[0066]

[Chemical 7] Example 6 Example 1 was repeated except that the reactive emulsifier used in Example 1 was replaced with 25 parts by weight of a reactive emulsifier represented by the following formula (Aderica Asorp SE-10N, manufactured by Asahi Denka Kogyo Co., Ltd.).
Emulsion polymerization was carried out in the same manner as above to obtain an aqueous emulsion composition.

[0067]

[Chemical 8] Example 7 Emulsion polymerization was carried out in the same manner as in Example 1 except that butyl cellosolve was used instead of the isopropyl alcohol used in Example 1 to obtain an aqueous emulsion composition.

Comparative Example 1 Emulsion polymerization was carried out in the same manner as in Example 1 without using isopropyl alcohol to obtain an aqueous emulsion composition.

Comparative Example 2 Emulsion polymerization was carried out in the same manner as in Example 1 without using the dihexyl phthalate used in Example 1 to obtain an aqueous emulsion composition.

Comparative Example 3 Emulsion polymerization was conducted in the same manner as in Example 1 except that 25 parts by weight of a non-reactive emulsifier (polyoxyethylene alkyl sulfate ammonium salt) was used in place of the reactive emulsifier used in Example 1. An aqueous emulsion composition was obtained.

With respect to the dry coatings of the aqueous emulsion compositions obtained in the above Examples and Comparative Examples, the water resistance of the coating, the adhesion to the substrate, the surface smoothness of the coating and the transparency of the coating were measured by the following test methods. , Was examined as follows.

(1) Water resistance test 5 g of an aqueous emulsion composition adjusted to a solid content concentration of 25% by weight was applied to a glass plate (8 cm × 6 cm), and the temperature was 20 ° C.
A test piece was obtained by drying for 1 week.

(A) Whitening time: The glass plate on which the film was formed was immersed in water at 20 ° C., a newspaper of 8 point type was laid down, and the time until the type became unreadable was measured.

(B) Water absorption: 5% of glass plate with coating
The piece was cut into a size of 5 cm × 5 cm, immersed in water at 20 ° C., and the increased weight after 48 hours was measured, and the water absorption rate was expressed as a weight percentage (%) relative to the film.

(2) Adhesion to substrate The aqueous resin composition was applied on the substrate shown in the table so that the film thickness after drying was 20 μm, and dried at 20 ° C. for 1 week to prepare a test piece. . The test piece was subjected to a cross-cut peeling test using an adhesive tape (registered trademark Cellotape manufactured by Nichiban Co., Ltd.) and evaluated according to the following criteria.

Excellent: The coating does not peel at all Good: A part of the coating (30 to 50%) peels off: Most of the coating (70 to 100%) peels (3) Smoothness of the glass plate The smoothness of the coating film formed above was visually evaluated according to the following criteria.

Excellent: Very good smoothness Good: Slightly poor smoothness Poor: Poor smoothness (4) Transparency The transparency of the coating film formed on the glass plate was visually evaluated according to the following criteria.

Excellent: Transparency is extremely good Good: Transparency is slightly inferior Poor: Transparency is inferior. The results are shown in the table. As is clear from the table, the use of the aqueous resin dispersions of Examples can greatly improve the water resistance and the adhesion to the substrate, as well as the surface smoothness and transparency of the coating film, as compared with the emulsions of Comparative Examples. Be improved.

[0079]

[Table 1]

Claims (11)

[Claims] 1. An aqueous emulsion composition obtained by polymerizing a polymerizable composition containing a polymerizable unsaturated monomer and a plasticizer in an aqueous medium in the presence of a hydrophilic organic solvent and a reactive emulsifier. object. 2. The aqueous emulsion composition according to claim 1, wherein the polymerizable unsaturated monomer is composed of a plurality of unsaturated monomers forming a copolymer having a glass transition temperature of 10 to 65 ° C. 3. The polymerizable unsaturated monomer forms (A) at least one hard monomer forming a polymer having a glass transition temperature of 50 ° C. or higher, and (B) a polymer having a glass transition temperature of 25 ° C. or lower. The aqueous emulsion composition according to claim 1, which is composed of at least one soft monomer and (C) a monomer having a carboxyl group or a salt thereof. 4. The polymerizable unsaturated monomer comprises (A) a hard monomer of 25 to 90% by weight, (B) a soft monomer of 10 to 70% by weight, and (C) a carboxyl group or a salt thereof. The aqueous emulsion composition according to claim 1, which is composed of 0.1 to 10% by weight of the monomer. 5. The aqueous emulsion composition according to claim 1, wherein the ratio of the plasticizer is 100 parts by weight with respect to 100 parts by weight of the polymerizable unsaturated monomer. 6. The aqueous emulsion composition according to claim 1, wherein the ratio of the hydrophilic organic solvent to 100 parts by weight of the polymerizable unsaturated monomer is 1 to 60 parts by weight. 7. The aqueous emulsion composition according to claim 1, wherein the ratio of the reactive emulsifier to 100 parts by weight of the polymerizable unsaturated monomer is 0.1 to 10 parts by weight. 8. (A) At least one hard monomer 30 to form a polymer having a glass transition temperature of 60 to 120 ° C.
80% by weight, (B) at least one soft monomer forming a polymer having a glass transition temperature of -100 to 0 ° C. 15 to 5
0% by weight and (C) 1 to 7% by weight of an unsaturated monomer having a carboxyl group or a salt thereof, and a polymerizable unsaturated monomer 100 forming a copolymer having a glass transition temperature of 15 to 50 ° C. A polymerizable composition containing (D) 5 to 15 parts by weight of a plasticizer, and (E) 5 to 50 parts by weight of a hydrophilic organic solvent to 100 parts by weight of a polymerizable unsaturated monomer. An aqueous emulsion composition obtained by polymerizing in an aqueous medium in the presence of 0.5 to 7.5 parts by weight of a reactive emulsifier with respect to 100 parts by weight of a polymerizable unsaturated monomer. 9. (A) Methacrylic acid alkyl ester,
Styrene monomer, at least one hard monomer selected from (meth) acrylonitrile and forming a polymer having a glass transition temperature of 70 to 110 ° C., selected from (B) alkyl acrylate, and having a glass transition temperature. At least 1 to form a polymer of -10 to -100 ° C
Unsaturated monomer containing one soft monomer and (C) an unsaturated monomer having a carboxyl group or a salt thereof (10)
The ratio of (D) phthalic acid-based plasticizer to 0 parts by weight is 5 to
15 parts by weight, the ratio of the water-soluble organic solvent (E) to 10 parts by weight of the polymerizable unsaturated monomer is 10 to 50 parts by weight, and the ratio of the reactive emulsifier to 100 parts by weight of the polymerizable unsaturated monomer is 1 to The aqueous emulsion composition according to claim 8, which is 7 parts by weight. 10. The aqueous emulsion composition according to claim 8, wherein the content of the hydrophilic organic solvent (E) in the aqueous medium is 1 to 40 parts by weight with respect to 100 parts by weight of water. 11. A method for producing an aqueous emulsion composition, which comprises emulsion-polymerizing a polymerizable composition containing a polymerizable unsaturated monomer and a plasticizer in an aqueous medium in the presence of a hydrophilic organic solvent and a reactive emulsifier. Method.