JPH01172412A - Manufacture of polymer particle - Google Patents

Abstract

PURPOSE:To produce easily crushable polymer particles in a high yield with environmental poluttion minimized, by subjecting a monomer such as a (meth) acrylate to suspension polymerization in the presence of a specific dispersion stabilizer, and adding a specific electrolyte to it. CONSTITUTION:A monomer is subjected to suspension polymerization in the presence of a dispersion stabilizer comprising three components, that is, a polymer compound (A) having a sulfonic acid group, a carboxyl group or an alkali metal salt group thereof in the molecule, an electrolyte (B-1) having a monovalent cation and an electrolyte (B-2) having a divalent or trivalent cation, and an electrolyte having a mono-, di- or tri-valent cation. As the monomer, one which contains 80wt.% or more at least one monomer selected from the group consisting of (meth)acrylates, aromatic vinyl compounds, cinnamates, (meth) acrylimide, and (meth)acrylonitrile is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing polymer particles, and more specifically, to a method for producing easily friable polymer particles in a high yield while reducing environmental pollution. The present invention relates to a method for producing polymer particles with a small amount of particles.

(Prior art and problems) Particulate polymers are used in toner resins for copying machines, resins for dental repairs, binder resins for green molded bodies of castings and ceramics, light diffusing agents, matting agents, adsorption column fillers, etc. It is used in various fields such as cosmetic additives,
The particle size, particle size distribution, resin composition, properties, etc. required for these particulate polymers are wide-ranging.

These particulate polymers are mainly produced by the suspended M polymerization method, but a technology that can meet the wide range of demands mentioned above has not yet been established, and their applications and amounts are still limited. has been done. Especially when the particle size is 100
- When producing the following polymer particles, there is a possibility that hemotsmer, etc. may escape in the water or the atmosphere during the production process, or that the yield may decrease due to the production of emulsion particles of 1- or less, and environmental pollution may occur. It has problems such as causing

Suspension polymerization has long been known as a method for polymerizing water-insoluble vinyl monomers in an aqueous medium.
It has advantages such as the particle size of the produced polymer is relatively large, making recovery work easy, and the purity of the produced polymer is relatively high.

Various stabilizers are added to stabilize the suspension polymerization reaction of monomers.1Stabilizers commonly used include nonionic synthetic polymers such as polyethylene oxide and polyvinyl alcohol, modified sodium lignin sulfonate, and modified sodium lignin sulfonate. (semi-)natural polymeric substances such as methylcellulose;
Ionic water-soluble polymeric substances such as sodium polyacrylate and poorly water-soluble inorganic compounds such as calcium carbonate and calcium phosphate are known.

However, when the above-mentioned substances are used as stabilizers, the stability of the dispersion system is insufficient, the particle size of the produced polymer increases, the formation of emulsion polymers, the amount of polymerized scale deposits increases,
There are problems such as coloration and turbidity of the polymer, and a decrease in the purity of the polymer.

Therefore, in order to improve the stability of the dispersion system during polymerization and reduce the amount of polymerized scale adhesion, we created a monomer mixture whose main component is (meth)acrylic acid ester, which has a special structure containing sulfonic acid groups. A method is known in which a polymerized substance is used in combination with an electrolyte containing a relatively large amount of monovalent cations (Japanese Patent Publication No. 4377/1983 and Japanese Patent Publication No. 6/1983).
0-49205).

However, although the above method is certainly effective in stabilizing the dispersion system during polymerization and reducing the amount of polymerized scale attached, it is said that it cannot produce fine particulate polymers with a particle size of 100° or less. There's a problem.

The present inventors conducted a study on a method for producing polymer particles with a particle size of lO〇 or less in high yield and without causing environmental pollution, and as a result, conducted a polymerization reaction using a specific dispersion stabilizer. It has been discovered that by adding an electrolyte after that, it is possible to obtain secondarily aggregated polymer particles that are easily friable, and the present invention has been achieved based on this discovery.

(Means to solve the problem) That is, the method for producing polymer particles of the present invention is as follows.

The monomer is (A) a polymer compound having a sulfonic acid group, a carboxyl group, or an alkali metal salt thereof in the molecule, (B-1) an electrolyte having a monovalent cation, and (B-2) a divalent Alternatively, it is characterized in that after suspension polymerization is carried out in the presence of a dispersion stabilizer made of an electrolyte having a trivalent cation, an electrolyte having a monovalent, divalent or trivalent cation is added.

The monomers used in the method of the present invention generally include those having copolymerizability, such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, and tert-acrylate. butyl,
Acrylic acid esters such as 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate,
tert-butyl methacrylate, 2-methacrylate
Methacrylic acid esters such as ethylhexyl, cyclohexyl methacrylate, phenyl methacrylate, and benzyl methacrylate; Aromatic vinyl compounds such as styrene, vinyltoluene, α-methylstyrene, monochlorostyrene, and dichlorostyrene; Cinnamate esters such as methyl cinnamate ; methacrylic acid imides such as methacrylic acid glutarimide; acrylonitrile or methacrylonitrile, preferably containing 80% by weight or more of at least one compound selected from the above group; Other monomers, such as vinyl esters of carboxylic acids such as vinyl acetate and vinyl propionate; acrylic acid,
Methacrylic acid, maleic anhydride, fumaric acid, cinnamic acid,
α,β-unsaturated acids such as sorbic acid; amides or imides of α,β-unsaturated acids such as acrylamide, methacrylamide, phenylmaleimide, cyclohexylmaleimide; vinyl halides such as vinyl chloride, vinylidene chloride, etc. In addition, polyfunctional monomers copolymerizable with these may be contained in an amount not exceeding 20% by weight, such as ethylene glycol dimethacrylate, tetraethylene glycol diacrylate, 1,4-butanediol diacrylate. , 1,3-butylene glycol dimethacrylate, 1,6-hexanediol diacrylate, divinylbenzene, etc.; trimethylolpropane triacrylate, triallyl trimellitate, allyl sorbate, diallyl maleate, diallyl fumarate ,
Trifunctional compounds such as triallyl cyanurate and triallyl isocyanurate; tetrafunctional compounds such as pentaerythritol tetraacrylate, etc. may be contained in an amount not exceeding 20% by weight.

In the method of the present invention, when carrying out suspension polymerization of the above-mentioned monomers, the above-mentioned (A) and (B-1) are used as dispersion stabilizers.
and (B-2) are used together.

That is, the polymer compound of component (A) constituting the dispersion stabilizer used in the present invention has a structural unit such as (meth)acrylic acid, an ester thereof, or a salt thereof, and
Contains a sulfonic acid group, a carboxyl group, or an alkali metal salt thereof in the molecule. As an alkali metal, Ll,
Na, etc. are mentioned. This component (A) is usually used in an amount of 0.005 to 5 parts by weight per 100 parts by weight of the monomer to be polymerized.

Such component (A) is produced, for example, as follows.

First, acrylate ester σ and/or methacrylate ester (acrylic compound [abbreviated as II),
Salts of acrylic acid and/or methacrylic acid (acrylic compounds [abbreviated as 1) and the following formula: [wherein R, w and K each represent H or CH; X is 10-1-NH- or represents -N(C)13)-; represents MifH, Li, Na, K or NHa; n represents an integer of 1 to 3] (acrylic compound [abbreviated as ml)] , ([II + [111+ [II[] )
For 100 parts by weight, [II is 0 to 40 parts by weight, [
11] in a composition ratio of 0 to 100 parts by weight and [ml] in a composition ratio of 0 to 100 parts by weight, and then produced in water and/or an organic solvent. The organic solvents used at this time include methanol, ethanol, acetone, methyl ethyl ketone,
Examples include N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, and the like.

The above-mentioned compound [I
The concentrations of I, [II] and [ml are not particularly limited, but when water is normally used as a solvent, it is preferably in the range of 5 to 40% by weight in order to facilitate the handling of the resulting polymer. , and the polymerization temperature is 30 to 150°C,
The polymerization time is preferably 1 to 20 hours.

Next, as a polymerization initiator, when water is used as a solvent, water-soluble inorganic oxides such as persulfates, perborates, and excessive acid salts may be used alone or in combination with a water-soluble reducing agent. In addition to redox initiation systems or redox initiation systems that combine hydrogen peroxide or hydroperoxide with a reducing agent, etc.
．． Azo compounds such as 2'-7zobis-2-cyanopentanoic acid can be used. Further, examples of the water-soluble reducing agent mentioned above include dextrose, Rongalit, acidic sodium sulfate, acidic sodium sulfite, and the like. Furthermore, when an organic solvent or a mixture of water and an organic solvent is used as a solvent, an organic polymerization initiator soluble in these, such as azobisisobutyronitrile, 2,2'-7zobis-2,4-dimethyl Valeronitrile, acetyl peroxide, cumene hydroperoxide, etc. can be used as the polymerization initiator.
+ [111+ [m]) 0 per 100 parts by weight
．． 005 to 5 parts by weight are used.

In addition to the polymerization initiator, a water-soluble mercaptan such as mercaptoethanol may be added for the purpose of adjusting the degree of polymerization, and these may be added in an amount of 0.01 to 3 parts by weight per 100 parts by weight of the starting material. use

The polymer compound (A) thus produced is produced in a suspended state in a solvent, and the viscosity of the suspension at a polymer concentration of 10% is preferably 20 to 20,000 cp.

Next, the components constituting the dispersion stabilizer used in the present invention (
B-1) and (B-2) will be explained.

Examples of the component (B-1) include electrolytes containing cations of alkali metals such as Li, Na, and ammonium ions, such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, carbon atoms of 1 to 4 carbon atoms, etc. salts of lower carboxylic acids, aliphatic or aromatic sulfonic acids, etc. Specific examples include potassium chloride, sodium sulfate, and sodium acetate.

These are usually used in an amount of 0.0005 to 0.05 parts by weight per 100 parts by weight of the monomer to be polymerized.

Component (B-2) includes Zn, Mg, Ca, Mn, C
Examples include electrolytes having cations of metals such as U, Ni, Fe, and A-type, such as salts of the acids listed in (B-1) above. Specific examples include zinc sulfate, aluminum sulfate, potassium aluminum sulfate, magnesium carbonate, and calcium chloride. These are the monomers to be polymerized.
Usually, 0.0005 to 0.05 parts by weight is used relative to 0 parts by weight.

If (B-1) and (B-2) are not added as dispersion stabilizers or the amount added is less than the above range, a polymer emulsion with a particle size of 1 g or less is produced in addition to normal particles of the produced polymer, which is preferable. do not have. On the other hand, if the amount added exceeds the above-mentioned range, the suspension polymerization system is finally destroyed and solidified through the process of producing giant particles of 100 μm or more or irregularly shaped particles.

Weight ratio of monomer phase and aqueous phase, monomer phase/aqueous phase is 1
/20 to 1/1, preferably jil/1.2
If the zero weight ratio of 178 to 178 is smaller than the above range, the productivity will decrease, and if it is larger, giant particles or irregularly shaped particles will be generated and solidified, which is not preferable.

The polymerization reaction process follows the conventional method of suspension polymerization reaction.

For example, a monomer phase and a solvent phase in which a dispersion stabilizer is dissolved are brought into contact with each other under high-speed stirring using a colloid mill or a homomixer to obtain a microdispersion of monomers with a particle size of 3 to 5 to 5. After that, the mixture is charged into a reaction vessel and polymerized with stirring.The reaction salinity is 30-120°C and the reaction time is 1-20 hours. Other methods for obtaining microdispersions include a method in which a solvent phase in which a dispersion stabilizer is dissolved and a monomer phase are ejected from pores under high pressure to obtain a particle size of about 1 to 20 μm; Examples include methods using a tech mixer or an ultrasonic mixer.

When carrying out the polymerization reaction, in addition to the monomer and the dispersion stabilizer, auxiliary agents such as a polymerization initiator, a chain transfer agent, and various lubricants and colorants can be added as necessary.

The polymerization initiator used includes known oil-soluble initiators, such as acetyl peroxide, propionyl peroxide, butyryl peroxide, caprylyl peroxide, octanoyl peroxide,
Diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, benzoyl peroxide;
tert-butyl peracetate, tert-butyl perpivalate, tert-butyl peroctanoate,
Peresters such as tert-butyl perbenzoate;
0 Polymerization initiators include azobis compounds such as 2,2'-7zobisisobutyronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile based on 100 parts by weight of monomers. Use .005 to 5 parts by weight.

Then, after the polymerization reaction has ended, an electrolyte containing monovalent, divalent or trivalent cations is added to the polymerization reaction. The electrolyte constitutes the above-mentioned dispersion stabilizer (B-1)
The electrolytes listed in and (B-2) can be used. By adding this specific electrolyte, secondarily aggregated and easily friable polymer particles can be obtained in high yield.

(Example) The following examples illustrate the invention in more detail.

In addition, in the examples, % represents weight %.

Component (A) constituting the blood deficiency-adjusting dispersion stabilizer was synthesized as follows.

(A-1) 30 g of methyl methacrylate, 70 g of potassium methacrylate, and 400 g of deionized water.

In a flask with an internal volume of 2000 Tnl, the temperature was raised to 70°C with stirring under a nitrogen atmosphere, 0.1 g of ammonium persulfate dissolved in 10 WJ of deionized water was added, and the temperature was raised to 80°C. Add 490g of 6-hour test water to dilute it, and cool it down to a polymer concentration of 10% and viscosity of 370cp (25°
A cloudy solution of C) was obtained.

(A-2) 10 g of sodium acrylate instead of 30 g of methyl methacrylate and 70 g of potassium methacrylate
A clear solution with a viscosity of 580 cp was obtained in the same manner as in (A-1) except that 0 g was used.

(A-3) 30 g of 2-ethylhexyl acrylate,
70 g of lithium methacrylate, 300 g of deionized water, and 100 g of methyl ethyl ketone were heated to 60° C. while stirring under a nitrogen atmosphere in a flask with an internal volume of 2,000 −,
0.1 g of ammonium persulfate dissolved in water was added and the temperature was raised to 70°C.

The mixture was diluted by adding 490 g of deionized water for 8 hours and cooled to obtain a cloudy white solution with a polymer content of 10% and a viscosity of 420 cp.

(A-4) 100 g of sodium salt of 2-sulfoethyl methacrylate and 900 g of deionized water were added to an inner volume of 2000
- in a flask at 50°C with stirring under nitrogen atmosphere.
Add 0.1g of ammonium persulfate to 60°C.
The temperature rose to . After 6 hours of cooling, a clear solution was obtained with a viscosity of 840 cp.

(A-5) Same procedure as in (A-4) except that 80 g of sodium salt of 2-sulfoethyl methacrylate and 20 g of methyl methacrylate were used instead of 100 g of sodium salt of 2-sulfoethyl methacrylate.
A slightly cloudy solution of cp was obtained.

(A-6) All << except that 60 g of sodium salt of 2-sulfopropyl methacrylate, 10 g of potassium acrylate, and 30 g of ethyl acrylate were used instead of 100 g of sodium ffi of 2-sulfoethyl methacrylate.
A cloudy white solution with a viscosity of 810 cp was obtained in the same manner as in (A-4).

After weighing and adding 3000g of deionized water and each component of the dispersion stabilizer shown in Table 1 to a beaker with an internal volume of 5cm, 970g of methyl methacrylate, 29g of ethyl acrylate,
1000 g of a monomer phase consisting of 1.5 g of n-octyl mercaptan, 4 g of lauroyl peroxide, and 1 g of glycerin monostearate was added. This was heated to 12,000 rp using TK-Auto Homo Mixer M type (manufactured by Tokushu Kakoki Kogyo ■).
After pre-mixing for 3 minutes at m to create a finely dispersed state,
The liquid was transferred to a flask with an internal volume of 5 fL, and while stirring at 350 rpm, it was heated at 80''C for 2 hours to perform suspension polymerization.Furthermore, the electrolyte shown in Table 1 was added, and the internal temperature was raised to 97°C.
The mixture was held for 30 minutes and then cooled to obtain polymer particles with secondary aggregation.

The produced polymer particles were evaluated for yield, ease of handling, and number average particle diameter, and the results are shown in Table 1.

[Shikom2] Experiments were conducted in the same manner as in Examples 1 to 5, except that the compounds shown in Table 1 were used as dispersion stabilizers and that no electrolyte was added after the polymerization reaction was completed. The products were evaluated in the same manner as in Examples 1 to 5, and the results are also listed in Table 1.

1 [L] Contents: 2500 g of deionized water in a 152 beaker,
As the component (A) of the dispersion stabilizer, (A-1) was added as a solid content of 4
After weighing and adding 6 g of g and (A-6) in solid content, 0.15 g of Na2 SO4 as component (B-1), and 0.07 g of AfL2 (SOa)3 as component (B-2), A monomer mixture having the composition shown in Table 2 and azobisisobutyronitrile as an initiator were added in the amounts shown in Table 2. This was made into a finely dispersed state by the same method as in Examples 1 to 5, and polymerization was carried out under the same conditions. After that, 30g of MgSO4 was added as an electrolyte and
The mixture was held for a minute and then cooled to obtain polymer particles in which secondary aggregation occurred.

The produced polymer particles were evaluated in the same manner as in Examples 1 to 5, and the results are shown in Table 2.

(Effects of the Invention) According to the present invention, easily friable polymer particles can be obtained in high yield, and substances that cause environmental pollution can be released into water or the atmosphere during the process. Therefore, it is possible to provide an efficient and excellent method for producing polymer particles.

Claims (2)

[Claims] (1) The monomer is (A) a polymer compound having a sulfonic acid group, a carboxyl group, or an alkali metal salt thereof in the molecule, (B-1) an electrolyte having a monovalent cation, and (B-2 ) Polymer particles characterized by suspension polymerization in the presence of a dispersion stabilizer consisting of an electrolyte having a divalent or trivalent cation, and then adding an electrolyte having a monovalent, divalent or trivalent cation. How the body is manufactured. (2) The monomer is at least one selected from the group consisting of acrylic ester, methacrylic ester, aromatic vinyl compound, cinnamic ester, acrylic imide, methacrylic imide, acrylonitrile, and methacrylonitrile at 80% by weight. % or more of the polymer particles according to claim 1.