JPH08113602A - Production of polymer emulsion - Google Patents

Abstract

PURPOSE: To produce a polymer emulsion having low-foaming properties and excellent polymerization stability by using a specified anionic surfactant in emulsion-polymerizing an unsaturated monomer. CONSTITUTION: An anionic surfactant represented by the formula (wherein R1 is H or methyl; R2 is a 1-4C alkyl; A is a 2-4C alkylenel; (l) is 1-3; (m) is 1-100; M is a monovalent or bivalent cation; and (n) is 1 or 2) is used in emulsion-polymerizing an unsaturated monomer. The compound represented by the formula can be obtained by effecting the addition reaction of a starting material which is a styrenized alkylphenol derivative obtained by reacting a phenol compound having 1-4C substituents with styrene or methylstyrene according to the usual method in the presence of a catalyst such as caustic soda or caustic potash with an alkylene oxide and reacting the adduct with a sulfating agent to form a sulfuric ester. When the degree of sulfation is 60% or above, the desired result can be attained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for emulsion polymerization of unsaturated monomers. More specifically, when emulsion-polymerizing monomers such as ethylenically unsaturated monomers and butadiene-based monomers, the use of a specific anionic surfactant results in low foaming and stable polymerization. The present invention relates to a method for producing a polymer emulsion having excellent properties.

[0002]

2. Description of the Related Art Conventionally, various surfactants such as acrylic acid ester polymers, ethylene-vinyl acetate copolymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, etc. have been prepared by emulsion polymerization. Methods for making polymers have been proposed.

For example, anionic surfactants such as long-chain alkyl sulfates, long-chain alkylbenzene sulfonates, polyoxyethylene alkylphenyl ether sulfates, and alkyldiphenyl ether disulfonates, or polyoxyethylene alkyl ethers, There is known a method of emulsion polymerization using a nonionic surfactant such as polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and pluronic type surfactant.

Originally, the surfactant used in the production of the polymer emulsion is not only involved in the initiation reaction and the formation reaction of the polymerization, but also the stabilization of the polymer emulsion during the polymerization and the formation of the produced polymer emulsion. It is deeply involved in the mechanical stability, chemical stability, freeze stability, pigment miscibility, storage stability, etc.

Further, it has a great influence on the physical properties such as particle size, viscosity and foaming property of the emulsion, and it is important to select a surfactant suitable for the use in selecting the surfactant.

In general, a nonionic surfactant is hardly affected by ions as can be inferred from its structure, and a polymer emulsion having good chemical stability can be obtained.
However, the amount of aggregates generated during the polymerization is relatively large compared to the anionic surfactant, and it is difficult to obtain a stable emulsion.

Since the anionic surfactant has an electrostatic repulsion effect on the hydrophilic group, a polymer emulsion having good stability can be obtained, but the anionic surfactant used is essentially Because it has the property of easily foaming,
It is a cause of various obstacles in the process of producing and using the polymer emulsion. That is, in the process of producing a polymer emulsion, the polymer emulsion being produced produces a lot of bubbles, which lowers the efficiency of heating and cooling, and hinders the recovery and removal of unreacted monomers. On the other hand, in the process of use, for example, when used in a vehicle for paints, paper processing, or adhesives, bubbles and pinholes remain in the resulting film due to foaming of the polymer emulsion, which causes the water resistance and adhesive strength of the film to increase. This is a cause of deterioration and poor finish of the final product.
An ideal surfactant in such a situation has not yet been found.

[0008]

In view of the above situation, the present invention, when emulsion-polymerizing an unsaturated monomer, uses a specific surfactant to provide a low foaming property and excellent polymerization stability. It is an object of the present invention to provide a method for producing a polymer emulsion.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted extensive studies and found that the anionic surfactant represented by the formula (I) is useful. Completed the invention.

That is, the present invention has the general formula

[0011]

Embedded image

(Wherein R ₁ is a hydrogen atom or a methyl group, R 1
₂ represents an alkyl group having 1 to 4 carbon atoms, and A represents an alkylene group having 2 to 4 carbon atoms. l is an integer of 1 to 3, m is 1 to 100
Is an integer. M is a monovalent or divalent cation.
n is an integer of 1 or 2 and is emulsion-polymerized in the presence of an anionic surfactant having a valence of the cation M), and has low foaming property and excellent polymerization stability. Another method is to produce a polymer emulsion.

In the general formula (I), A has 2 to 4 carbon atoms.
And examples thereof include an ethylene group, a propylene group, and a butylene group. These alkylene groups form an oxyalkylene group together with an oxygen atom.
The oxyalkylene group may be the same or different mixture (block or random), preferably an oxyethylene group, a propylene group, or a mixture of an oxyethylene group and a propylene group (block or random). Propylene groups are preferred.

In the above, l is an integer of 1 to 3,
The integer 2 is preferred. m is an integer of 1 to 100, preferably 5 to 70, and particularly preferably m is 5 to 50. When m is 100 or more, the emulsion polymerization stability becomes poor. R ₂ is a lower alkyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, an isopropyl group and a butyl group. A methyl or butyl group is preferable, and a methyl group is particularly preferable. M is 1 or 2
Examples are valent cations such as alkali metals such as sodium and potassium; alkaline earth metals such as calcium and magnesium; ammonium; organic amine cations such as water-soluble alkanolamines and lower alkylamines. Of these, sodium or ammonium is particularly preferable.

The following are examples of typical compounds represented by the general formula (I) used in the present invention.

1) Polyoxyethylene (7) [distyrenated (methylphenyl ether)] sulfuric acid ammonium salt 2) Polyoxypropylene (8) [distyrenated (methylphenyl ether)] sulfuric acid ammonium salt 3) Polyoxyethylene (30) [Distyrenated (methylphenyl ether)] sulfuric acid ammonium salt 4) Polyoxyethylene (12) [Distyrenated (butylphenyl ether)] sulfuric acid ester soda salt 5) Polyoxyethylene (10) [methyldistyrenated (Methylphenyl ether)] Sulfate ester soda salt 6) Polyoxypropylene (20) [Methyl distyrenated (methylphenyl ether)] Sulfate ester salt 7) [Polyoxypropylene (5) Polyoxyethylene (6)] Random [ Styrenated (methyl phenyl ether) sulfate ammonium salt 8) [polyoxypropylene (10) polyoxyethylene (20)] block [distyrenated methylphenyl ether) sulfate sodium salt.

In the above-mentioned examples, polyoxyethylene (12) shows that ethylene oxide is added on average 12 mol, and polyoxypropylene (8) is shown that propylene oxide is added on average 8 mol,
Others follow this.

The compound represented by the general formula (I) is obtained by reacting a phenol compound substituted with an alkyl group having 1 to 4 carbon atoms with styrene or methylstyrene according to a conventional method.

[0019]

Embedded image

A styrenated alkylphenol derivative represented by the formula (wherein R ₁ , R ₂ and 1 have the same meanings as described above) is used as a starting material and is produced according to a method known per se.

That is, alkylene oxide is added to compound (II) in the presence of a catalyst such as caustic soda or potassium hydroxide to produce a compound represented by the formula (III),

[0022]

[Chemical 4]

(Wherein R ₁ , R ₂ , and 1 have the same meanings as described above), then sulfuric acid anhydride, chlorosulfonic acid, sulfamic acid,
It can be converted to the anionic surfactant (I) of the present invention by converting it to a sulfuric acid ester with a sulfating agent such as sulfuric acid. The above-mentioned sulfuric acid esterification reaction does not necessarily have to be 100% reacted, and a reaction rate of 60% or more, preferably 75 to 95% can sufficiently obtain a desired effect. The sulfuric acid esterified product thus obtained can be neutralized to form an alkali metal salt such as sodium or potassium, an ammonium salt, a water-soluble alkanolamine salt, or the like.

Examples of monomers that can be advantageously emulsion polymerized by the method of the present invention include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, Esters of acrylic acid or methacrylic acid such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; halogenated vinyls such as vinyl bromide, vinyl chloride and vinylidene chloride; acetic acid, propionic acid , Vinyl esters of fatty acids such as tertiary synthetic saturated carboxylic acids: aromatic vinyls such as styrene and α-methylstyrene: monoolefins such as ethylene and butadiene, or conjugated diolefins: vinyl cyanides such as acrylonitrile : Α, β-unsaturated amides such as acrylic amide: acrylic acid Methacrylic acid, itaconic acid,
Examples include α, β-unsaturated carboxylic acids such as maleic acid and fumaric acid.

As the polymerization initiator, an initiator usually used for emulsion polymerization can be used without particular limitation. For example, potassium, sodium, ammonium persulfate or perborate, and inorganic such as hydrogen peroxide. Peroxide; organic peroxide such as benzoyl peroxide, di-t-butyl peroxide, peracetic acid; 2,2-azobisisobutyronitrile, 4-azobis- (4-cyanopentanoic) acid or its alkali A radical-forming polymerization initiator such as a metal salt can be used, and the amount thereof is 0.01 to 3.0.
%, Preferably 0.1 to 2.0%, more preferably 0.1 to 1.0% by weight.

If a peroxide is used, the above-mentioned peroxide can be used in combination with a reducing agent such as ascorbic acid, soluble sulfite, hydrosulfite or thiosulfate, if necessary. In combination with a metal monomer that generates a heavy metal ion or a metal compound that generates a metal ion in water such as ferrous sulfate, it can be used as a redox polymerization initiator.

A chain transfer agent can also be used in combination,
As such, for example, t-dodecyl mercaptan, dodecyl mercaptan, carbon tetrachloride, chloroform, triphenylmethane and the like can be used.

Furthermore, additives conventionally used in emulsion polymerization technology, such as chelating agents, buffering agents, salts of organic acids, or solvents, can be used.

The surfactant represented by the general formula (I) of the present invention is 0.5 to 10 parts by weight, preferably 1 to 7 parts by weight, and more preferably 1 to 5 parts by weight with respect to 100 parts by weight of the monomer. It is suitable to use in the range of parts by weight.

In the method for producing the polymer emulsion of the present invention, the anionic surfactant represented by the above general formula (I) exerts its function sufficiently by itself. Agents, reactive emulsifiers, high molecular weight emulsifiers, protective colloids and the like can also be used in combination. Examples of surfactants that can be used in combination include long-chain alkyl sulfates, long-chain alkylbenzene sulfonates, and polyoxyethylene alkylphenyl ethers as anionic surfactants.
Tersulfate, alkyldiphenyl ether disulfonate, etc., and nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, pluronic type Examples thereof include a surfactant.

Examples of polymeric emulsifiers that can be used in combination include polyvinyl alcohol, poly (meth) acrylic acid salts, polyhydroxyalkylene (meth) acrylate, and the like, as protective colloids that can be used in combination, such as sodium alginate. Examples thereof include anionic protective colloids such as, and nonionic protective colloids such as hydroxyethyl cellulose.

When used in combination with an anionic surfactant, a nonionic surfactant, a polymeric emulsifier and / or a protective colloid, it is contained in an amount of 0.05 to 0.5 parts by weight per 1 part by weight of the anionic surfactant according to the present invention. About 10 parts by weight is suitable.

In the present invention, the polymer emulsion is
It can be obtained by a generally known emulsion polymerization method. As such a method, there are (1) batch charging method, (2) monomer addition method and (3) monomer emulsion addition method, and a preferable method is the monomer emulsion addition method.

[0034]

INDUSTRIAL APPLICABILITY The anionic surfactant represented by the general formula (I) of the present invention has a styryl group in the hydrophobic group portion of its molecule and has a strong adsorptive power, so that it has an interface with polymerizable monomers. A polymer emulsion having excellent tension lowering ability, emulsifying power, and solubilizing power, resulting in low foaming property and excellent polymerization stability (specifically, the amount of aggregates produced during polymerization is small). It can be manufactured. Further, the polymer emulsion obtained by the present invention is surprisingly freezing stable, although it is produced with the anionic surfactant (I).
It has excellent chemical stability and water resistance, and also has good storage stability.

[0035]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, in each Example, a part represents a weight part and% represents weight%. The evaluation criteria of the obtained polymer emulsion are as follows.

1. Aggregate amount: The polymer emulsion after the completion of emulsion polymerization was filtered through a 100 mesh screen, the aggregate remaining on the screen was dried at 110 ° C. for 2 hours, and the weighed weight was expressed as a weight% with respect to the monomer used to stabilize the polymerization. It was evaluated as sex.

2. Solid content: 1 g of the polymer emulsion was taken, 5 g of pure water was added, and the evaporation residue after drying at 105 ° C. for 2 hours was expressed in%.

3. Viscosity: The viscosity of the polymer emulsion before neutralization at 25 ° C. was measured with a B-type rotary viscometer at 60 rpm (unit: mPs).

4. Foaming property: 100 ml of polymer emulsion adjusted to a solid content of 10% has a diameter of 45 mm and a height of 350
It is taken in a 500 ml graduated cylinder with a ground stopper of mm, and the whole volume (ml number) immediately after forced shaking for 30 seconds is measured,
Further, it was left still as it was, and after 5 minutes, the whole volume (number of ml) was measured.

5. Freezing stability: According to JIS-K6828, keep the polymer emulsion at −10 ° C. for 16 hours, 2
After standing at 5 ° C. for 8 hours, the mixture was stirred with a glass rod and judged based on the presence or absence of change in emulsion state and change in viscosity. ◯ ... Very stable Δ: Some changes in viscosity were observed, but overall stable × ... Very unstable and gelled overall.

6. Chemical stability: Polymer emulsion 2
0 g was placed in a 30 ml test tube, 5 ml of 40% calcium chloride aqueous solution was added, and the appearance was observed. ○: No change ×: Aggregate was generated.

7. Water resistance of polymer film: A polymer film prepared by applying a polymer emulsion on a glass plate was immersed in water at 25 ° C, and the whitening state of the film was evaluated. ◯: No whitening after 1 hour Δ: Whitening within 10 to 30 minutes x: Immediate whitening

8. Storage stability: The appearance after observing the polymer emulsion at room temperature for 6 months was observed. A: No change C: Aggregate generation or thickening is observed.

[Example 1] 120 parts of styrene, 80 parts of 2-ethylhexyl acrylate, 4 parts of acrylic acid, 95 parts of ion-exchanged water, 1 part of ammonium persulfate, and the surfactant polyoxyethylene (7) [distyrene] according to the present invention. (Methylphenyl ether)] sulfuric acid ester ammonium salt (4 parts) was mixed to prepare a monomer emulsion (304 parts).

Next, 76 parts of deionized water and 15.2 parts of the above-mentioned monomer emulsion were charged into a reactor equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, and stirring was started.
The temperature was raised to 80 ° C. in a nitrogen stream, and initial polymerization was performed for 30 minutes.
Then, the remaining monomer emulsion (288.8 parts) was added to 80 parts.
Polymerization was carried out by continuously dropping and polymerizing at 3 ° C. for 3 hours and aging for 1 hour after completion of dropping.

Example 2 Emulsification under the same conditions as in Example 1 except that 4 parts of the surfactant polyoxypropylene (8) [distyrenated (methylphenyl ether)] sulfate ester ammonium salt according to the present invention was used. Polymerization was performed to obtain a polymer emulsion.

Example 3 Emulsification under the same conditions as in Example 1 except that 4 parts of the surfactant polyoxyethylene (12) [distyrenated (butylphenyl ether)] sulfate ester soda salt according to the present invention was used. Polymerization was performed to obtain a polymer emulsion.

Comparative Example 1 Emulsion polymerization was carried out under the same conditions as in Example 1 except that 4 parts of a representative known surfactant polyoxyethylene (4) nonylphenyl ether sulfate ammonium salt was used. A combined emulsion was obtained.

COMPARATIVE EXAMPLE 2 Emulsion polymerization was carried out under the same conditions as in Example 1 except that 4 parts of a representative known surfactant, sodium dodecylbenzene sulfonate, was used to obtain a polymer emulsion.

Next, the above Examples 1 to 3 and Comparative Example 1
Table 1 shows the evaluation results of the polymer emulsions obtained in Examples 1 to 2.

[0051]

[Table 1]

[Example 4] 98 parts of butyl acrylate, 98 parts of methyl methacrylate, 4 parts of acrylic acid, 100 parts of ion-exchanged water, 1 part of ammonium persulfate, and the surfactant polyoxyethylene (7) [distyrene according to the present invention] (Methyl phenyl ether)] sulfuric acid ester ammonium salt (3 parts) was mixed to prepare 305 parts of a monomer emulsion.

Next, 100 parts of deionized water and 3 parts of the above-mentioned monomer emulsion were charged into a reactor equipped with a stirrer, a thermometer, a reflux condenser and a dropping funnel, and stirring was started. The temperature was raised to 0 and the initial polymerization was carried out for 30 minutes. Subsequently, the remaining 302 parts of the monomer emulsion was continuously dropped and polymerized at 80 ° C. for 3 hours, and after the dropping was completed, aging was carried out for 1 hour to obtain a polymer emulsion.

Example 5 Surfactant Polyoxyethylene (12) [Methyl Distyrenated (Methyl Phenyl Ether)] Sulfate Ammonium Salt 3 According to the Invention
Emulsion polymerization was carried out under the same conditions as in Example 4 except that parts were used to obtain a polymer emulsion.

[Example 6] Surfactant according to the present invention [polyoxypropylene (5) polyoxyethylene (6)] random distyrenated (methylphenyl ether)] sulfuric acid ester ammonium salt except that 4 parts were used. Emulsion polymerization was carried out under the same conditions as in Example 4 to obtain a polymer emulsion.

[Comparative Example 3] A polymer emulsion was prepared by emulsion polymerization under the same conditions as in Example 4 except that 3 parts of a representative known surfactant octylphenoxy ethoxy ethyl sulfonic acid sodium salt was used. Got

Comparative Example 4 Emulsion polymerization was carried out under the same conditions as in Example 4 except that 4 parts of a representative known surfactant polyoxyethylene (5) tridecyl ether sulfate soda salt was used. A combined emulsion was obtained.

Next, Examples 4 to 6 and Comparative Example 3 described above.
Table 2 shows the evaluation results of the polymer emulsions obtained in Examples 1 to 4.

[0059]

[Table 2]

Example 7 100 parts of butyl acrylate,
Methyl methacrylate 60 parts, styrene 36 parts, acrylic acid 4 parts, ion-exchanged water 100 parts, ammonium persulfate 1
Part and surfactant relating to the present invention polyoxyethylene (23) [distyrenated (methyl phenyl ether)]
3 parts of a sulfate ammonium salt was mixed to prepare 305 parts of a monomer emulsion. Next, stirrer, thermometer,
A reactor equipped with a reflux condenser and a dropping funnel was charged with 100 parts of deionized water and 3 parts of the above monomer emulsion, stirring was started, the temperature was raised to 80 ° C. in a nitrogen stream, and initial polymerization was carried out for 30 minutes. . Subsequently, the remaining 302 parts of the monomer emulsion was continuously added dropwise at 80 ° C. over 3 hours for polymerization, and after completion of the addition, aging was carried out for 1 hour to obtain a polymer emulsion.

[Example 8] Example 8 except that 3 parts of the surfactant [polyoxypropylene (10) polyoxyethylene (20)] block [distyrenated methylphenyl ether]] sulfuric acid ester soda according to the present invention was used. Emulsion polymerization was performed under the same conditions as in 7 to obtain a polymer emulsion.

[Comparative Example 5] Emulsion polymerization was carried out under the same conditions as in Example 7 except that 3 parts of a representative known surfactant, sodium lauryl sulfate, was used to obtain a polymer emulsion.

Comparative Example 6 Emulsion polymerization was carried out under the same conditions as in Example 7 except that 3 parts of a representative known surfactant, sodium dioctylsulfosuccinate, was used to obtain a polymer emulsion.

Next, Examples 7 to 8 and Comparative Example 5 described above.
Table 3 shows the evaluation results of the polymer emulsions obtained in Examples 1 to 6.

[0065]

[Table 3]

As is clear from the results of Table 1, Table 2 and Table 3, by using the anionic surfactant according to the present invention in the production of the polymer emulsion, low foaming property and stable polymerization were obtained. It exhibits an excellent effect.

Claims (3)

[Claims] 1. When emulsion-polymerizing an unsaturated monomer,
A method for producing a polymer emulsion, which comprises polymerizing in the presence of an anionic surfactant represented by the following general formula (I). Embedded image (In the formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a carbon atom 1
~ 4 alkyl group, A represents an alkylene group having 2 to 4 carbon atoms. l is an integer of 1 to 3 and m is an integer of 1 to 100. M is a monovalent or divalent cation. n is an integer of 1 or 2 and represents the valence of the cation M. ) 2. In the above general formula (I), A represents an alkylene group having 2 to 3 carbon atoms, m is 5 to 70, and M is
The method for producing a polymer emulsion according to claim 1, wherein is a sodium salt, an ammonium salt or a monoethanolamine salt. 3. In the above general formula (I), A represents an alkylene group having 2 to 3 carbon atoms, m is 5 to 50, and M is
The method for producing a polymer emulsion according to claim 1, wherein is a sodium salt or an ammonium salt.