JP2788489B2 - Emulsifier for emulsion polymerization and method for producing polymer emulsion using the emulsifier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an emulsifier for emulsion polymerization of unsaturated monomers and a method for producing a polymer emulsion using the emulsifier. More specifically, an emulsifier for emulsion polymerization capable of maintaining the stability of the polymer emulsion during polymerization and the resulting polymer emulsion, and significantly improving the foaming property of the polymer emulsion and the water resistance when formed into a film, and a polymer using the emulsifier The present invention relates to a method for producing an emulsion.

(Prior art) Today, polymer emulsions are superior to organic solvent solutions of polymers in many aspects such as stability, workability, and cost, and are used in a wide range of fields such as paints, adhesives, and fiber processing. It is consumed in large quantities.

This polymer emulsion is produced by emulsion polymerization of an unsaturated monomer in an aqueous medium in the presence of an emulsifier, and conventionally, as an emulsifier, for example, an alkyl sulfate or a polyoxyethylene alkyl ether sulfate. Anionic low molecular surfactants or nonionic low molecular surfactants such as polyoxyethylene alkyl ether and polyoxyethylene alkyl phenyl ether are mainly used.

These emulsifiers prevent the formation of agglomerates and smoothly promote the reaction during emulsion polymerization, and the resulting polymer emulsion has stability such as chemical stability, mechanical stability, storage stability, and freeze stability. In order to maintain this, the type and amount of the unsaturated monomer to be polymerized are appropriately selected and used depending on the type of the obtained polymer emulsion and the use of the obtained polymer emulsion.

However, when an anionic low molecular surfactant is used, the resulting polymer emulsion has a drawback that it is easily affected by the electrolyte and lacks chemical stability. On the other hand, nonionic low molecular surfactants need to be used in larger amounts than anionic low molecular surfactants in order to maintain the stability of the resulting polymer emulsion, and a large amount of emulsifier remains as impurities in the product. Had the disadvantage of doing so. Furthermore, polymer emulsions obtained using these low molecular surfactants are difficult to handle because of their high foaming properties, and the surfactants that are impurities when formed into a film are water-soluble. It had a drawback of poor water resistance.

In order to solve these problems, reactive emulsifiers and polymer emulsifiers have been proposed in recent years. Examples of the reactive emulsifier include α, β-unsaturated carboxylic acid monoesters of nonionic surfactants (JP-A-56-72091) and alkylene oxide adducts of (meth) acrylic acid (JP-A- 51-5386), (meth) acrylic acid esters of polyoxyalkylene monoallyl ethers (
And a polymer emulsifier such as polyacrylic acid and / or a copolymer of acrylic acid and 2-hydroxyethyl methacrylate (Japanese Patent Application Laid-Open No.
-206604) is known.

These emulsifiers, although slightly improved in water resistance and foaming properties as compared with the low-molecular surfactant described above,
It is still necessary to use a large amount of the emulsion, and it has disadvantages such as poor stability of the high-concentration emulsion.

(Problems to be Solved by the Invention) The present invention is to solve the problems of the above-mentioned conventional emulsifiers.

Accordingly, an object of the present invention is to provide an emulsion polymerization emulsifier which can maintain the stability of emulsion polymerization and the resulting polymer emulsion, and can significantly improve the foaming property of the polymer emulsion and the water resistance of the film when formed into a film. An object of the present invention is to provide a method for producing a polymer emulsion using the emulsifier.

(Means for Solving the Problems) The present inventors have conducted intensive studies to achieve the above object, and as a result, have reached the present invention.

That is, the present invention relates to an emulsifier used when an unsaturated monomer is emulsion-polymerized in an aqueous medium to produce a polymer emulsion, and (a) a general formula (I): (Wherein, R ¹ is hydrogen or a methyl group, and X is an alkylene oxide residue having 2 to 4 carbon atoms comprising 50% by weight or more of ethylene oxide residues based on the total weight of all alkylene oxide residues. And n is an integer from 3 to 300;
² is hydrogen, an alkyl group having 1 to 3 carbon atoms or 2 to 2 carbon atoms.
And at least one structural unit (A) represented by general formula (II): (Wherein, R ³ is hydrogen or a methyl group, and R ⁴ has ⁴ carbon atoms.
An alkyl group, an alkenyl group, an aryl group, an aralkyl group, a cyclic alkyl group, a cyclic alkenyl group, or —COOR ⁵ (where R ⁵ is an alkyl group having 4 to 30 carbon atoms,
An alkenyl group, an aryl group, an aralkyl group, a cyclic alkyl group or a cyclic alkenyl group)) and at least one of the structural units (B) represented by And at least one structural unit (C) formed by copolymerization of a copolymerizable monomer with a content of the structural unit (A) of 97 to 40% by weight and a content of the structural unit (B). Is 3 to 60% by weight, structural unit (C)
Is 0 to 30% by weight, and the average molecular weight is
A polymer emulsifier comprising a polymer (C) in the range of 0 to 500,000; and (b) a low molecular ionic surfactant having a hydrophobic group having 8 to 30 carbon atoms and an ionic group. And an emulsifier for emulsion polymerization.

Further, the present invention provides a method for producing a polymer emulsion, comprising using the above-mentioned emulsifier for emulsion polymerization as an emulsifier when producing a polymer emulsion by emulsion-polymerizing an unsaturated monomer in an aqueous medium. About.

 Hereinafter, the present invention will be described in detail.

In the general formula (I) representing the hydrophilic structural unit (A) constituting the polymer (C) in the present invention,-(X) _n -represents n alkylene oxide residues having 2 to 4 carbon atoms, that is, poly An oxyalkylene group is shown, and 50% by weight or more of all the alkylene oxide residues are ethylene oxide residues. N indicating the total number of moles of the alkylene oxide is an integer of 3 to 300, preferably 3 to 100. R ² is a terminal group of a polyoxyalkylene chain, and is a hydrogen atom, an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, etc.), or an alkenyl group (vinyl group, methylvinyl group, allyl group, etc.) ).

R ⁴ in the general formula (II) representing the hydrophobic structural unit (B) is an alkyl group having 4 to 30 carbon atoms, an aryl group, —CO
Although organic group represented by OR ^5, Specific examples of groups other than the group represented by -COOR ^5, n- butyl, n- hexyl, 2-ethylhexyl group, n- octyl group, n-
Nonyl group, 1,3,5-trimethylhexyl group, decyl group,
Alkyl groups such as dodecyl group and octadecyl group; alkenyl groups such as butenyl group, decenyl group and oleyl group; aryl groups such as phenyl group, methylphenyl group, octylphenyl group, nonylphenyl group and naphthyl group; benzyl group and methylbenzyl Groups, aralkyl groups such as phenethyl group; cyclic alkyl groups such as cyclohexyl group and dimethylcyclohexyl group; cyclic alkenyl groups such as cyclopentenyl group. As the R ⁵ in the group represented by -COOR ⁵ in R ^4, R ⁴ above
And the same groups as the groups other than -COOR ^{5 in the} above.

Regarding the content of each structural unit constituting the polymer (C) in the present invention, the structural unit (A) is 97 to 40% by weight, preferably 95 to 50% by weight, and the structural unit (B) is 3 to 60% by weight. %, Preferably 5 to 50% by weight, and the total content of the structural units (A) and (B) in the polymer (C) is 70% by weight or more. Polymers outside these ranges have too high a hydrophobic or hydrophilic property, and the polyoxyalkylene chain and the hydrophobic chain cannot be balanced. Therefore, when emulsion polymerization is carried out using such a polymer, problems such as formation of a large amount of aggregates during polymerization and remarkable decrease in stability of the obtained polymer emulsion occur.

The molecular weight of the polymer (C) is desirably 1,000 to 500,000, preferably 3,000 to 300,000.

The method for obtaining the polymer (C) is not particularly limited, and it can be produced by any method. For example, (1) a vinyl monomer which forms a structural unit (A) represented by the general formula (I) by polymerization and a vinyl monomer which forms a structural unit (B) represented by the general formula (II) A method of copolymerizing a monomer with another monomer, if necessary, (2)
Esterification of a raw material polymer that produces a polymer (C) containing a structural unit (A) and a structural unit (B) by modification such as an esterification reaction with an alcohol, with an alcohol or an alkyl halide, etc. Reaction, an addition reaction of an alkylene oxide, or a method of modifying a polyoxyalkylene chain by a terminal modification reaction.

In the method (1), examples of the vinyl monomer that produces the hydrophilic structural unit (A) include a polyalkylene glycol derivative or a vinyl ester of an alkylene oxide adduct as shown below. Also contains at least 50% by weight of ethylene oxide units based on the total weight of the polyoxyalkylene chain, and these terminal alkoxylates are monomers alkoxylated with an alkyl group having 1 to 3 carbon atoms, and the terminal alkenoxylates Is a monomer alkenylated with an alkenyl group having 2 to 5 carbon atoms.

Specific examples of the vinyl monomer that forms the structural unit (A) include, for example, polyalkylene glycol mono (meth) acrylates such as polyethylene glycol mono (meth) acrylate and polyethylene glycol-polypropylene glycol mono (meth) acrylate; Glycol (meth) acrylate, methoxy polyethylene glycol-polypropylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol-polypropylene glycol (meth) acrylate, etc., alkoxylated with an alkyl group having 1 to 3 carbon atoms. Alkoxypolyalkylene glycol (meth) acrylate; carbon number 2 such as aryloxy polyethylene glycol (meth) acrylate Such as 5 alkenoxy reduction has been alkenoxy polyalkylene glycol (meth) acrylate with an alkenyl group can be exemplified, of 1
Species or two or more can be used.

In the method (1), the hydrophobic structural unit (B)
Examples of the vinyl monomer for producing the compound include aliphatic vinyl compounds such as 1-hexene, 1-octene, isooctene, 1-nonene, 1-decene, 1-dodecene, and vinylcyclohexane; styrene, α-methylstyrene, p −
Aromatic vinyl compounds such as methylstyrene, 3-phenyl-1-propene and vinylnaphthalene; butyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate,
Phenyl (meth) acrylate, naphthyl (meth) acrylate, p-methylphenyl (meth) acrylate,
Octylphenyl (meth) acrylate, nonylphenyl (meth) acrylate, dinonylphenyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, etc., as well as alkyl groups, alkenyl groups, and aryls having 4 to 30 carbon atoms Group, an aralkyl group, a cyclic alkyl group, and a (meth) acrylate having a cyclic alkenyl group.
Species or two or more can be used.

Among these monomers, a monomer which can be easily obtained and gives a polymer (C) which produces a polymer emulsion having excellent stability and water resistance is an alkyl group having 4 to 20 carbon atoms. (Meth) acrylate, alkylphenyl (meth) acrylate having an alkyl group having 1 to 10 carbon atoms as a substituent, styrene, α-methylstyrene and α-olefin having 6 to 22 carbon atoms. Monomers are particularly preferred.

As described above, the ratio of the monomer that can be used in the case of producing the polymer (C) by the method (1) is such that the content in the polymer (C) after polymerization is the structural unit ( A) 97-
40% by weight, preferably 95 to 50% by weight, structural unit (B) 3
The proportion is such that the total content of the structural unit (A) and the structural unit (B) is 70% by weight or more.

Therefore, a monomer that forms a structural unit (C) other than the structural unit (A) and the structural unit (B) after polymerization is in a range that does not impair the effects of the present invention, that is, the polymer (C) of the structural unit. It can be copolymerized with a monomer that forms the structural unit (A) and a monomer that generates the structural unit (B) by using the content within the range of 30% by weight or less.
A monomer that forms a structural unit (C) other than such a structural unit (A) and a structural unit (B), that is, a “monomer that forms the structural units (A) and (B)” "Copolymerizable monomer" means the following.

(Meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth) allyl sulfonic acid, sulfoethyl (meth) acrylate, styrene sulfonic acid, vinyl sulfonic acid, 2-acrylamide-2-methylpropane sulfonic acid, (Meth) acrylamide, N-methylol (meth) acrylamide, dimethylaminoethyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, methyl (meth) acrylate, Ethyl (meth) acrylate, n-propyl (meth) acrylate, ethylene, propylene, isobutylene, acrylonitrile and vinyl chloride.

These can be used alone or in combination of two or more.

In order to produce the polymer (C) by the method (1), the monomer component may be copolymerized by a known method using a polymerization initiator. The copolymerization can be carried out by a method such as polymerization in a solvent or bulk polymerization.

The polymerization in the solvent can be carried out batchwise or continuously, and examples of the solvent used include water; lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; benzene, toluene, xylene, cyclohexane, Aromatic, aliphatic or heterocyclic compounds such as n-hexane and dioxane; ketone compounds such as ethyl acetate, acetone and methyl ethyl ketone; Examples of the polymerization initiator include persulfates such as ammonium persulfate and sodium persulfate, peroxides such as benzoyl peroxide and lauroyl peroxide, hydroperoxides such as cumene hydroperoxide, and aliphatics such as azobisisobutyronitrile. An azo compound or the like is used. In this case, an accelerator such as an amine compound may be used in combination. The polymerization temperature is
It is appropriately determined depending on the solvent and the polymerization initiator used,
Usually, it is carried out within a range of 0 to 150 ° C.

In the bulk polymerization, peroxides such as benzoyl peroxide and lauroyl peroxide, hydroperoxides such as cumene hydroperoxide as polymerization initiators,
Using an aliphatic azo compound such as azobisisobutyronitrile and azobisdimethylvaleronitrile, 50 to 150
It is performed within a temperature range of ° C.

In addition, the copolymer obtained by copolymerization in this manner can be used as it is as a polymer emulsifier, but if necessary, the solvent used in the polymerization may be separated or removed, or another solvent or water may be used. Can be used in place of Alternatively, a basic substance such as a hydroxide or oxide of an alkali metal or alkaline earth metal, a carbonate, ammonia, or an organic amine may be added as a pH adjuster before use.

Next, when producing the polymer (C) by the method (2), the raw material polymer to be subjected to the modification and the modification method are as follows: (a) a (meth) acrylic acid-based polymer as a raw material;
A method by an esterification reaction with an alcohol which forms the structural unit (A) after the modification and an alcohol or an alkyl halide which forms the structural unit (B), (b) a (meth) acrylic acid system having the structural unit (B) A method in which an esterification reaction with an alcohol to form a structural unit (A) is performed using a copolymer as a raw material, and (c) a structure obtained by adding an alkylene oxide to a (meth) acrylic acid-based polymer having a structural unit (B). A method of introducing a unit (A), (d) a method of subjecting a (meth) acrylic acid ester-based polymer as a raw material to a transesterification reaction with an alcohol which forms a structural unit (A) and a structural unit (B) after modification. (E) (1)
And the polymer obtained by the method (a) to (c) of (2), wherein the terminal group of the polyoxyalkylene chain is an —OH group, and the terminal —OH group is used as the starting polymer. Examples of the method include denaturation by a method such as etherification, (meth) acryloylation, or dimethylacryloylation.

When the polymer (C) is obtained by each method of (2), the following conditions must be satisfied. That is, the content of the structural unit (A) in the polymer (C) after modification is 97 to 40% by weight, preferably 95 to 50% by weight, and the content of the structural unit (B) is 3 to 60% by weight. %, Preferably 5 to 50% by weight, and the total content of the structural units (A) and (B) in the polymer (C) must be 70% by weight or more,
When the alkylene oxide is added to introduce the structural unit (A), the content of the ethylene oxide unit in the polyoxyalkylene chain after the addition needs to be 50% by weight or more.

Specific examples of the method (a) include, as a (meth) acrylic acid-based polymer which is a raw material polymer that can be used, poly (meth) acrylic acid or a copolymer of acrylic acid and methacrylic acid. And one or two of these polymers and an alcohol capable of producing a structural unit (A) such as polyethylene glycol, methoxypolyethylene glycol, methoxypolyethylene glycol-polypropylene glycol, ethoxypolyethylene glycol, and allyloxypolyethylene glycol. Above, and butanol, octanol, dodecanol,
Oleyl alcohol, phenol, nonylphenol,
The polymer (C) can be obtained by esterifying one or more alcohols capable of forming the structural unit (B) such as benzyl alcohol by a known method.

Specific examples of the method (b) include, for example, a (meth) acrylate having an alkyl group having 4 to 30 carbon atoms and an alkyl having a alkyl group having 1 to 10 carbon atoms as a substituent. Phenyl (meth) acrylate, styrene, α-methylstyrene, having 4 to 30 carbon atoms
And copolymers of (meth) acrylic acid with one or two or more kinds of α-olefins having a substituent represented by the following formula (A). A method of esterifying the alcohol producing A) with a known method can be used.

Examples of the raw material polymer that can be used in the method (c) include the same copolymers as those described in the method (b). These copolymers include ethylene oxide and, if necessary, propylene oxide or propylene oxide. The polymer (C) can be obtained by adding an alkylene oxide such as butylene oxide by a known method.

The method (d) uses a lower alkyl ester of poly (meth) acrylic acid such as poly (methyl) methacrylate or poly (meth) ethyl acrylate, or a copolymer of methyl acrylate and methyl methacrylate as a raw material. One or two kinds of alcohols capable of forming a structural unit (A) such as polyethylene glycol, methoxypolyethylene glycol, methoxypolyethylene glycol-polypropylene glycol, ethoxypolyethylene glycol, and allyloxypolyethylene glycol; Using one or more of the above and alcohols capable of forming a structural unit (B) such as butanol, octanol, dodecanol, oleyl alcohol, phenol, nonylphenol, and benzyl alcohol,
The polymer (C) can be obtained by a transesterification reaction according to a known method.

The method (e) is a method in which a polymer having a polyoxyalkylene chain whose terminal group is an —OH group is used as a raw material and the terminal is modified. Examples of the etherification modification include, for example, the raw material polymer and an alkyl group having 1 to 3 carbon atoms such as methyl chloride, methyl bromide, ethyl chloride, propyl chloride, and allyl chloride or an alkenyl group having 2 to 3 carbon atoms. And a method in which a Williamson reaction is performed by a known method using at least one selected from halogenated hydrocarbons. In order to perform modification such as (meth) acryloylation or (iso) crotonoylation, the raw material copolymer and one or more kinds selected from (meth) acrylic acid, (iso) crotonic acid, dimethylacrylic acid and the like are used. May be esterified by a known method.

The hydrophobic group having 8 to 30 carbon atoms constituting the low molecular ionic surfactant (b), which is another component of the emulsifier for emulsion polymerization of the present invention, is not particularly limited. Alkyl groups such as dodecyl group and heptadecyl group; alkenyl groups such as decenyl group, 8-heptadecenyl group and oleyl group; 11-hydroxyheptadecyl group and 11
A hydroxyalkyl group such as a hydroxyundecyl group; an aryl group such as an octylphenyl group, a nonylphenyl group, and a naphthyl group. Examples of such a low molecular ionic surfactant having a hydrophobic group include an anionic surfactant, a cationic surfactant, and an amphoteric surfactant.

Examples of the anionic surfactant include lauric acid (salt), stearic acid (salt), oleic acid (salt), ricinoleic acid (salt), and 12-hydroxystearic acid (salt).
Fatty acid (salt) or a modified product thereof; alkyl sulfate (salt) such as lauryl sulfate (salt) and stearyl sulfate (salt); alkylbenzenesulfonic acid (salt) such as dodecylbenzenesulfonic acid (salt); poly Higher alcohol ethoxylate sulfate (salt) such as oxyethylene dodecyl ether sulfate (salt), polyoxyethylene nonylphenyl ether sulfate (salt), polyoxyethylene-sec-alkyl ether sulfate (salt); α- Olefin sulfonic acid (salt); alkyl naphthalene sulfonic acid (salt); dialkyl sulfosuccinic acid (salt); sulfosuccinic acid monoalkyl ester (salt); higher alcohol ethoxylate sulfosuccinic acid monoester (salt); alkyl phosphoric acid (salt); Sulfated fatty acid Ether (salt); and the like (polyoxyethylene) alkyl ether carboxylic acid (salt); petroleum sulfonic acid (salt). These can be used alone or in combination of two or more.

Each of these low molecular weight anionic surfactants is an acid having a hydrophobic group or a salt thereof, but the kind of the salt is not particularly limited. For example, alkali metal salts such as sodium salt and potassium salt; magnesium salt , Calcium salts and other alkaline earth metal salts; ammonium salts; alkylamine salts such as methylamine salts, dimethylamine salts, trimethylamine salts, ethylamine salts, diethylamine salts, triethylamine salts; monoethanolamine salts, diethanolamine salts, triethanolamine Alkanolamine salts such as salts; and pyridinium salts.

Examples of low molecular weight cationic surfactants include primary amines (salts) such as laurylamine (salt), stearylamine (salt) and benzylamine (salt); dilaurylamine (salt), distearylamine ( Tertiary amines (salts) such as lauryl dimethylamine (salt) and stearyl dimethylamine (salt); lauryl trimethyl ammonium (salt), stearyl trimethyl ammonium (salt), diamine Quaternary ammonium (salt) such as stearyldimethylammonium (salt), laurylbenzyldimethylammonium (salt), cetylpyridinium (salt); (di) hydroxyethylalkylamine (salt); polyoxyethylene alkylamine (salt) Is mentioned.

These low molecular weight cationic surfactants are amine compounds or salts thereof, or quaternary ammonium salts. The type of the salt is not particularly limited. For example, the salts of amine compounds include acetate, Formate, hydrochloride, hydrogen bromide and the like, and quaternary ammonium salts include quaternary ammonium chloride and quaternary ammonium bromide.

Examples of low-molecular zwitterionic surfactants include amino acid-type zwitterionic surfactants such as laurylaminopropionic acid (salt), stearylaminopropionic acid (salt), and nitrilolaurildiacetic acid (salt); lauryl dimethyl betaine, stearyl dimethyl Betaine types such as betaine, lauryl dihydroxyethyl betaine, 2-undecyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, 2-heptadecyl-N-sodiumcarboxymethyl-N-carboxymethyloxyethylimidazolinium betaine Zwitterionic surfactants; phosphate (salt) type zwitterionic surfactants such as lecithin; and sulfonic acid (salt) type zwitterionic surfactants.

In the emulsifier for emulsion polymerization of the present invention, the proportions of the polymer emulsifier (a) and the low molecular ionic surfactant (b) used are respectively 20 to 99% by weight, preferably 30 to 95% by weight and 1 to 80% by weight. %, Preferably 5 to 70% by weight.

In the present invention, the unsaturated monomer that can be emulsion-polymerized using the emulsifier for emulsion polymerization can be appropriately selected according to the use of the obtained polymer emulsion, and includes, for example, (meth) acrylic acid and (meth) acrylic acid. Methyl acrylate,
Ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
Acrylic unsaturated monomers such as acrylonitrile and (meth) acrylamide; vinyl ester unsaturated monomers such as vinyl acetate; vinyl halide unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl bromide; Aromatic unsaturated monomers such as styrene and α-methylstyrene;
One or a mixture of two or more of olefinic unsaturated monomers such as ethylene, propylene, butadiene, isoprene and chloroprene can be mentioned.

In the present invention, when the unsaturated monomer is emulsion-polymerized in an aqueous medium using the emulsifier for emulsion polymerization, the amount of the emulsifier used is 0.1 to 100 parts by weight of the unsaturated monomer used for polymerization. 20 parts by weight, preferably 0.2 to 5 parts by weight.

The emulsifier for emulsion polymerization may be used in combination with a commonly used low-molecular nonionic surfactant or polyvinyl alcohol, or a protective colloid such as hydroxyethyl cellulose as long as the effects of the present invention are not impaired. Absent.

In the present invention, the polymerization conditions for emulsion polymerization using the emulsifier for emulsion polymerization may be performed according to ordinary conditions. For example, the polymerization can be usually performed at a temperature of 20 to 100 ° C. depending on the type of the unsaturated monomer and the type of the polymerization initiator used. Known polymerization initiators may be used, for example, inorganic peroxides such as hydrogen peroxide, ammonium persulfate and sodium persulfate; organic peroxides such as benzoyl peroxide and peracetic acid; azobisisobutyrate An azo compound such as lonitrile and azobisdimethylvaleronitrile can be used. Further, a redox initiator using a reducing agent such as sodium hydrogen sulfite, sodium thiosulfate, and ferrous sulfate together as a polymerization accelerator may be used.

The emulsion polymerization method in the present invention may be in accordance with a usual emulsion polymerization method.For example, an unsaturated monomer or an unsaturated monomer may be emulsified in an aqueous medium containing an emulsifier for emulsion polymerization maintained at the above temperature. The polymerization may be performed by continuously feeding the emulsion and the polymerization initiator emulsified in an aqueous medium using the polymerization, or the polymerization may be performed by initially charging the unsaturated monomer and the initiator collectively. . The concentration of the unsaturated monomer at the time of emulsion polymerization may be appropriately determined depending on the use of the obtained polymer emulsion, but is generally 20 to 70% by weight.
Range.

(Effect of the Invention) The emulsifier for emulsion polymerization of the present invention strongly adheres to the polymer emulsion particles formed from the emulsion polymerization process to after the completion of the reaction and contributes to the dispersion stabilization of the particles. Compared with an emulsifier such as an activator, the obtained polymer emulsion has an effect of improving the stability such as chemical stability, mechanical stability, storage stability and freezing stability.

In addition, there is almost no bubbling when handling the obtained polymer emulsion, and the handleability is good. Furthermore, after the polymer emulsion obtained by using the emulsifier for emulsion polymerization of the present invention was formed into a film, when the film came into contact with water, since the elution of the emulsifier from the film was extremely small, the water resistance of the film was significantly improved. A polymer emulsion is obtained.

(Examples) Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Parts and% are based on weight.

Reference Example 1 50 parts of toluene was charged into a flask equipped with a thermometer, a stirrer, two dropping funnels, a gas inlet tube, and a reflux condenser.
Heated to 0 ° C. Thereafter, while maintaining the same temperature under a nitrogen stream, 75 parts of methoxypolyethylene glycol acrylate (containing 23 ethylene oxide units on average per molecule, average molecular weight of 1099) as a monomer for forming the structural unit (A) A monomer mixture solution consisting of 25 parts of dodecyl acrylate (molecular weight 240) and 50 parts of toluene as a monomer for forming the structural unit (B) was dropped over 120 minutes,
At the same time, a polymerization initiator solution comprising 1.5 parts of azobisisobutyronitrile and 50 parts of toluene was added dropwise from the other dropping funnel over 180 minutes. After the completion of the dropwise addition, the temperature was further maintained at the same temperature for 60 minutes to complete the polymerization. At this time, the polymerization rate of each monomer was 98% for methoxypolyethylene glycol acrylate as a result of GPC analysis, and 98% for dodecyl acrylate as a result of gas chromatographic analysis. GP)
C analysis and other monomers were determined by gas chromatographic analysis to determine the degree of polymerization). The average molecular weight of the obtained polymer was 22,000 as a result of GPC analysis using polystyrene as a standard (see Reference Example below). Similarly, the average molecular weight of the obtained polymer was determined by GPC analysis.) afterwards,
The solvent was distilled off under reduced pressure to obtain a polymer (1).

Reference Example 2 The same reactor as in Reference Example 1 was charged with 50 parts of toluene, the atmosphere in the flask was replaced with nitrogen under stirring, and the flask was heated to 80 ° C. in a nitrogen stream. Then, while maintaining the same temperature under a nitrogen stream,
Methoxy polyethylene glycol methacrylate (an average of 9 per molecule) is used as a monomer for forming the structural unit (A).
Containing 3 ethylene oxide units, average molecular weight 49
6) A monomer mixture solution composed of 85 parts, 15 parts of styrene (molecular weight 104) and 50 parts of toluene as monomers for forming the structural unit (B) was dropped over 120 minutes, and simultaneously from the other dropping funnel. , Azobisdimethylvaleronitrile 1.0
And a polymerization initiator solution composed of 50 parts of toluene and dropwise added over 180 minutes. After the completion of the dropwise addition, the temperature was further maintained at the same temperature for 60 minutes to complete the polymerization. At this time, the polymerization rate of each monomer is methoxypolyethylene glycol methacrylate.
98% and styrene were 99%, and the average molecular weight of the obtained polymer was 70,000. Thereafter, the solvent was distilled off under reduced pressure to obtain a polymer (2).

Reference Example 3 As in Reference Example 1, isopropyl alcohol 50 was added to the reactor.
The flask was charged with nitrogen, the atmosphere in the flask was replaced with nitrogen under stirring, and the flask was heated to 80 ° C. under a nitrogen stream. Then, while maintaining the same temperature under a nitrogen stream, 10 parts of polyethylene glycol monoacrylate (containing 5 ethylene oxide units on average per molecule, average molecular weight of 292) as a monomer for forming the structural unit (A). And 60 parts of methoxypolyethylene glycol acrylate (containing an average of 10 ethylene oxide units per molecule, average molecular weight of 526), 30 parts of 2-ethylhexyl methacrylate (molecular weight of 198) as a monomer for forming the structural unit (B), and A monomer mixture solution consisting of 50 parts of isopropyl alcohol was added dropwise over 120 minutes, and simultaneously from the other dropping funnel 1.0 parts of azobisdimethyl valeronitrile and 5 parts of isopropyl alcohol 5
A polymerization initiator solution consisting of 0 parts was added dropwise over 180 minutes. After the completion of the dropwise addition, the temperature was further maintained at the same temperature for 60 minutes to complete the polymerization. At this time, the polymerization rate of each monomer was 97% for polyethylene glycol monoacrylate, 98% for methoxypolyethylene glycol acrylate, and 99% for 2-ethylhexyl methacrylate. The average molecular weight of the obtained polymer was 10,000,000. there were. Thereafter, the solvent was distilled off under reduced pressure to obtain a polymer (3).

Reference Example 4 In the same manner as in Reference Example 1, 50 parts of toluene was charged into a reactor, the atmosphere in the flask was replaced with nitrogen under stirring, and 80 parts of nitrogen was supplied under a nitrogen stream.
Heated to ° C. Thereafter, while maintaining the same temperature under a nitrogen stream, 60 parts of methoxypolyethylene glycol methacrylate (containing 15 ethylene oxide units on average per molecule, average molecular weight of 761) as a monomer for forming the structural unit (A) And 30 parts of styrene (molecular weight: 104) and 1-decene (molecular weight: 1) as monomers for forming the structural unit (B).
40) Mix monomer solution consisting of 10 parts and 50 parts of toluene
The mixture was added dropwise over 120 minutes, and at the same time, 0.5 part of azobisisobutyronitrile and 5 parts of toluene were added from the other addition funnel.
A polymerization initiator solution consisting of 0 parts was added dropwise over 180 minutes. After the completion of the dropwise addition, the temperature was further maintained at the same temperature for 60 minutes to complete the polymerization. At this time, the polymerization rate of each monomer was 97% for methoxypolyethylene glycol methacrylate and 99% for styrene.
%, 1-decene was 95%, and the average molecular weight of the obtained polymer was 150,000. Thereafter, the solvent was distilled off under reduced pressure to obtain a polymer (4).

Reference Example 5 The same reactor as in Reference Example 1 was charged with 50 parts of benzene, the atmosphere in the flask was replaced with nitrogen under stirring, and the flask was heated to 80 ° C. in a nitrogen stream. Then, while maintaining the same temperature under a nitrogen stream,
Ethoxypolyethylene glycol methacrylate (30 on average per molecule) as a monomer to form the structural unit (A)
Containing 1 ethylene oxide unit, average molecular weight 143
6) A monomer mixture solution consisting of 90 parts, 10 parts of stearyl methacrylate (molecular weight 338) as a monomer for producing the structural unit (B) and 50 parts of benzene was dropped over 120 minutes,
At the same time, a polymerization initiator solution consisting of 1.0 part of azobisisobutyronitrile and 50 parts of benzene was added dropwise from the other dropping funnel over 180 minutes. After the completion of the dropwise addition, the temperature was further maintained at the same temperature for 60 minutes to complete the polymerization. At this time, the polymerization rate of each monomer was 97% for ethoxy polyethylene glycol methacrylate and 99% for stearyl methacrylate, and the average molecular weight of the obtained polymer was 100,000. Thereafter, the solvent was distilled off under reduced pressure to obtain a polymer (5).

Example 1 Using the polymer (1) obtained in Reference Example 1 and sodium lauryl sulfate as an emulsifier, emulsion polymerization was carried out by the following method, and the stability during polymerization and the chemical stability of the obtained polymer emulsion were obtained. , Mechanical stability, freezing stability, foaming property and water resistance of the film formed into a film were evaluated by the following methods. Table 1 shows the evaluation results.

(Emulsion polymerization method) In a flask equipped with a thermometer, a stirrer, three dropping funnels, a gas inlet tube and a reflux condenser, 120 parts of water, 1.4 parts of the polymer (1) and 0.6 parts of sodium dodecyl sulfate were charged, and nitrogen flow was carried out. Heated down to 60 ° C. Then, while maintaining the same temperature under a nitrogen stream, 16 parts of the unsaturated monomer mixture consisting of 40 parts of butyl acrylate and 40 parts of styrene,
0.96 parts out of 6.72 parts of a 5% aqueous solution of sodium persulfate and 0.9 out of 6.72 parts of a 2.5% aqueous solution of sodium bisulfite
6 parts were dripped at a time from different dropping funnels, respectively, to initiate polymerization. Thereafter, 64 parts of the remaining unsaturated monomer mixture was added dropwise over 120 minutes, and at the same time, the remaining aqueous sodium persulfate solution and aqueous sodium bisulfite solution were added dropwise over 180 minutes. After completion of the dropwise addition, the mixture was further maintained at the same temperature for 120 minutes to complete the polymerization, thereby obtaining a polymer emulsion.

(Evaluation method) (1) Stability at the time of polymerization The obtained polymer emulsion was filtered with a 80-mesh wire gauze, and the filtration residue was washed with water and dried. The amount of the obtained aggregate was represented by% by weight based on the charged monomer.

(2) Chemical stability The obtained polymer emulsion was diluted to 1% with water, and a 0.5 mol / aqueous solution of calcium chloride was added dropwise thereto, and the concentration of calcium chloride in the emulsion at the time when the aggregation of emulsion particles started was determined. It was expressed in mmol /.

(3) Mechanical stability A certain amount of the obtained polymer emulsion was stirred with a homogenizer at 10,000 rpm for 30 minutes, and the formed aggregates were removed.
The mixture was filtered through a 100-mesh wire net, and the residue was washed with water and dried. The amount of the obtained aggregates was represented by% by weight based on the solid content in the collected emulsion.

(4) Freezing stability The obtained polymer emulsion was left at -10 ° C and 20 ° C for 6 hours each, repeatedly frozen and thawed, and represented by the number of repetitions until the emulsion was broken.

(5) Foaming property 10 ml of test solution obtained by diluting the obtained polymer emulsion 10-fold with water is placed in a test tube having a volume of 50 ml and a height of 20 cm and shaken at 300 rpm for 30 seconds using a shaker. Height was displayed in cm.

(6) Water resistance After applying the obtained polymer emulsion on a slide glass, it was air-dried to form a film having a heat of 0.2 mm.
After further drying at 60 ° C. for 10 hours, the film was immersed in water, and the whitening state of the film after 24 hours was observed. The evaluation criteria are as follows.

：: No whitening Δ: Slightly whitening ×: Whitening Example 2 The procedure of Example 1 was repeated except that 1.8 parts of the polymer (2) obtained in Reference Example 2 and 0.2 part of potassium laurate were used as emulsifiers. Emulsion polymerization was carried out in the same manner, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 In Example 1, 1.5 parts of the polymer (3) obtained in Reference Example 3 and polyoxyethylene (n =
9) Emulsion polymerization was carried out in the same manner as in Example 1 except that 0.5 part of sodium dodecyl ether sulfate was used, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4 In Example 1, 1.0 part of the polymer (4) obtained in Reference Example 4 and polyoxyethylene (n = 1) were used as emulsifiers.
2)-sec-alkyl (C ₁₂ ~ ₁₄₎ except for using 1.0 parts of sulfosuccinic acid half ester sodium salt of ether performs emulsion polymerization in the same manner as in Example 1, evaluated of the obtained polymer emulsion Performed in the same manner as in Example 1. The results are shown in Table 1.

Example 5 In Example 1, 1.6 parts of the polymer (5) obtained in Reference Example 5 and n-dodecylamine hydrochloride 0.4 were used as emulsifiers.
Emulsion polymerization was carried out in the same manner as in Example 1 except that parts were used, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 1 Emulsion polymerization was carried out in the same manner as in Example 1 except that 2.0 parts of the polymer (1) obtained in Reference Example 1 was used as an emulsifier, and the obtained polymer emulsion was evaluated. Was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 Emulsion polymerization was performed in the same manner as in Example 1 except that 0.2 part of sodium lauryl sulfate was used as an emulsifier, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. Was. The results are shown in Table 1.

Comparative Example 3 Emulsion polymerization was carried out in the same manner as in Example 1 except that 2.0 parts of polyoxyethylene (n = 20) nonylphenyl ether was used as the emulsifier, and the obtained polymer emulsion was evaluated. Was performed in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 Emulsion polymerization was carried out in the same manner as in Example 1 except that 2.0 parts of an acrylate of polyoxyethylene (n = 20) nonylphenyl ether was used as the emulsifier. Evaluation of the emulsion was performed in the same manner as in Example 1. The results are shown in Table 1.

Example 6 Instead of butyl acrylate / styrene (50/50 weight ratio) in Examples 1-5 and Comparative Examples 1-4, 2-ethylhexyl acrylate / methyl methacrylate / styrene (40/40/20 weight ratio) Emulsion polymerization was performed by the following method using an unsaturated monomer mixture consisting of the following, and the obtained polymer emulsion was evaluated in the same manner as in Example 1.
Table 1 shows the evaluation results.

(Emulsion polymerization method) 70 parts of water, 0.64 part of the polymer (1) obtained in Reference Example 1 and polyoxyethylene (n) were placed in the same reactor as in Example 1.
= 12) -n-Dodecyl ether 0.16 parts of potassium acetate was charged and heated to 60 ° C under a nitrogen stream. Then, while maintaining the same temperature under a nitrogen gas stream, 32-ethylhexyl acrylate 32 parts, methyl methacrylate 32 parts, styrene 16 parts, water 50
Parts, 0.96 part of polymer (1) and polyoxyethylene (n
= 12) -26.2 parts of unsaturated monomer emulsion prepared by vigorously shaking 0.24 parts of potassium n-dodecyl ether acetate in a dropping funnel, 0.96 parts of 6.72 parts of 5% aqueous solution of sodium persulfate and sulfurous acid Sodium hydrogen 2.5
The polymerization was started by dropping 0.96 part of each of the 6.72 parts aqueous solution at a time from a separate dropping funnel. Thereafter, the polymerization was completed in the same manner as in Example 1 to obtain a polymer emulsion.

Example 7 In Example 6, 1.5 parts of the polymer (2) obtained in Reference Example 2 as an emulsifier and stearyl dimethyl betaine were used.
Emulsion polymerization was carried out in the same manner as in Example 6, except that 0.5 parts were used, 40% of each of which was charged into a reactor, and the remaining 60% was used for preparing an unsaturated monomer emulsion. The obtained polymer emulsion was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8 In Example 6, 1.0 part of the polymer (3) obtained in Reference Example 3 and 1.0 part of sodium lauryl sulfate were used as emulsifiers, and 40% of each of them was charged into a reactor.
Emulsion polymerization was carried out in the same manner as in Example 6, except that the remaining 60% was used for preparing an unsaturated monomer emulsion, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. went. The results are shown in Table 1.

Comparative Example 5 In Example 6, 2.0 parts of sodium lauryl sulfate was used as an emulsifier, of which 40% was charged into a reactor.
Emulsion polymerization was carried out in the same manner as in Example 6, except that the remaining 60% was used for preparing an unsaturated monomer emulsion, and the obtained polymer emulsion was evaluated in the same manner as in Example 1. went. The results are shown in Table 1.

Comparative Example 6 In Example 6, 2.0 parts of polyoxyethylene (n = 20) nonylphenyl ether was used as an emulsifier, of which 40% was charged into a reactor and the remaining 60% was an unsaturated monomer emulsion. The emulsion polymerization was carried out in the same manner as in Example 6 except that the emulsion was used for the preparation of E.g., and the obtained polymer emulsion was evaluated in the same manner as in Example 1. The results are shown in Table 1.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-73804 (JP, A) JP-A-60-58402 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 2/22-2/30 B01F 17/00-17/56

Claims (4)

(57) [Claims] 1. An emulsifier used for producing a polymer emulsion by emulsion-polymerizing an unsaturated monomer in an aqueous medium, comprising: (a) a general formula (I): (Wherein, R ¹ is hydrogen or a methyl group, and X is an alkylene oxide residue having 2 to 4 carbon atoms comprising 50% by weight or more of ethylene oxide residues based on the total weight of all alkylene oxide residues. And n is an integer from 3 to 300;
² is hydrogen, an alkyl group having 1 to 3 carbon atoms or 2 to 2 carbon atoms.
And at least one structural unit (A) represented by general formula (II): (Wherein, R ³ is hydrogen or a methyl group, and R ⁴ has ⁴ carbon atoms.
60, the alkyl group, an alkenyl group, an aryl group, an aralkyl group, a cyclic alkyl, cyclic alkenyl group, or a -COOR ⁵ (where,, R ⁵ is of 4 to 60 carbon atoms, an alkyl group,
An alkenyl group, an aryl group, an aralkyl group, a cyclic alkyl group or a cyclic alkenyl group)) and at least one of the structural units (B) represented by And at least one structural unit (C) formed by copolymerization of a copolymerizable monomer, wherein the content of the structural unit (A) is 97 to 40% by weight, and the content of the structural unit (B) is Is 3 to 60% by weight, structural unit (C)
Is 0 to 30% by weight, and the average molecular weight is
A polymer emulsifier comprising a polymer (C) in the range of 0 to 500,000; and (b) a low molecular ionic surfactant having a hydrophobic group having 8 to 30 carbon atoms and an ionic group. Emulsifier for emulsion polymerization. 2. A polymer emulsifier (a) in an emulsifier for emulsion polymerization.
And (1) the proportion of the low molecular ionic surfactant (b) is 20 to 99% by weight and 80 to 1% by weight, respectively.
3. The emulsifier for emulsion polymerization according to 1.). 3. The emulsion polymerization emulsifier according to claim 1, wherein the unsaturated monomer is emulsion-polymerized in an aqueous medium to produce a polymer emulsion.
A method for producing a polymer emulsion, which is used at a ratio of 0.1 to 20 parts by weight per part by weight. 4. The amount of an emulsifier for emulsion polymerization used is an unsaturated monomer.
The method for producing a polymer emulsion according to claim 3, wherein the amount is 0.2 to 5 parts by weight per 100 parts by weight.