JPH02155935A - Preparation of flame-retardant porous polymer particle - Google Patents

Abstract

PURPOSE:To make particle diameter relatively small and to improve hardness, strength and heat resistance by incorporating a polymerizable monomer contg. a crosslinkable monomer and a halogenated monomer and an unreactive solvent in a specified seed polymer and polymerizing them. CONSTITUTION:A polymerizable monomer (B) contg. 10-55wt.% crosslinkable monomer (e.g. divinybenzene) and 30-90wt.% halogenated monomer [e.g. 2,2-[bis(4-methacryloyloxy-3,5-dibromophenyl)propane] and an unreactive solvent (C) (e.g. toluene) are incorporated into an aq. dispersion (A) contg. a seed particle of a weight-average MW in terms of PS of 500-10,000 and a particle diameter of 0.2-0.8mum at 2-18pts.wt. components B and C based on the component A and the components B and C are absorbed in the component A. Then, the mixture is polymerized to obtain a flame-retardant porous polymer with a particle diameter of 0.1-2mum.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing flame-retardant porous polymer particles, particularly porous polymer particles having a relatively small particle size, highly cross-linked, and flame-retardant. The present invention relates to a manufacturing method.

[Prior art] Porous polymer particles having a particle size in the range of several μm to 0.1 μm, which is the normal particle size range of polymer particles, produced by emulsion polymerization method or soap-free polymerization method are stably and industrially advantageous. Manufacturing methods that can be used are disclosed in JP-A-63-77689 and JP-A-83-189413. However, these porous polymer particles are usually flammable, which limits their use in applications requiring flame retardancy.

[Problems to be Solved by the Invention] Under the above circumstances, the present invention enables stable and industrially advantageous production of flame-retardant porous polymer particles having a relatively small particle diameter of several μm to 0.1 μm. A manufacturing method is provided.

[Means for solving the problems] The present invention provides polystyrene equivalent weight average molecular weight of 500 to 500.
Both a polymerizable monomer and a non-reactive solvent are added in an amount of 2 to 18 parts by weight per 1 part by weight of the seed polymer particles to an aqueous dispersion containing seed polymer particles having a molecular weight of 10,000. and a method of polymerizing by absorbing a non-reactive solvent, the method for producing flame-retardant porous polymer particles containing 10% by weight or more of a crosslinking monomer and 30% by weight or more of a halogen-containing monomer in the polymerizable monomer. It is related to.

The present invention will be explained in detail below.

One of the characteristics of the method of the present invention is that polymer particles having a specific weight average molecular weight are used as so-called seed polymer particles. That is, the seed polymer particles used in the present invention have a polystyrene equivalent weight average molecular weight of 500 to 10,000, preferably 700 to 7.
000, more preferably 1.000 to e, ooo.

In the present invention, the "weight average molecular weight" of polymer particles is the weight average molecular weight in terms of polystyrene measured by a conventional method such as gel permeation chromatography.

When the weight average molecular weight of the seed polymer particles exceeds 10.000, the ability of the seed polymer particles to absorb monomers and non-reactive solvents is small, and the monomers independently polymerize without being absorbed by the seed polymer particles.
In addition to producing a large amount of polymer particles with a particle size different from the intended one, these foreign particles are particularly small and colloidally unstable, which worsens the stability of the polymerization reaction system and causes coagulation during polymerization. Things start to occur in large quantities.

Further, when the weight average molecular weight of the seed polymer particles is less than 500, the molecular weight is too small and the absorption capacity of the ribolimer is low, causing the same problem as above.

In addition, since the particle size and particle size distribution of the seed polymer particles affect the particle size and particle size distribution of the flame-retardant porous polymer particles that are produced, it is important to have a uniform particle size that is controlled as much as possible and has a narrow particle size distribution. Preferably, seed polymer particles are used. Specifically, seed polymer particles with a particle size of 0.2 to 0.8 μm and a narrow particle size distribution, for example, those with a coefficient of variation of 10% or less, are preferably used.

The composition of the seed polymer particles is not particularly limited as long as it dissolves or swells in the monomer used for polymerization, but it is preferably of the same type as the monomer used for polymerization. Specifically, polystyrene and other polymer particles are preferably used.

The method for obtaining such seed polymer particles is not particularly limited, but for example, they can be synthesized by an emulsion polymerization method or a soap-free polymerization method using a relatively large amount of a mercaptan-based molecular weight regulator. In the H-forming of the seed polymer particles, it is preferable to use a seed polymerization method using seed particles in order to control the particle size.

In the present invention, the crosslinking monomer preferably includes two or more of divinyl compounds typified by divinylbenzene, or polyvalent (meth)acrylate compounds typified by trimethylolpropane trimethacrylate and trimethylolpropane triacrylate. A compound having two polymerizable double bonds can be used.

Examples of polyvalent (meth)acrylate compounds that can be used in the present invention include the following compounds.

Diacrylate compounds polyethylene glycol diacrylate, 1゜3-butylene glycol diacrylate, 1,6-hexane glycol diacrylate, neopentyl glycol diacrylate, polypropylene glycol diacrylate,
2.2-bis(4-acryloxybrobyloxyphenyl)propane, 2'-bis(4-acryloxyjethoxyphenyl)propane triacrylate compound trimethylolpropane triacrylate, trimethylolethane triacrylate, Tetramethylolmethane triacrylate Tetraacrylate compound Tetramethylolmethanetetraacrylate dimethacrylate compound Ethylene glycol dimethacrylate, diethylene gelicold dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1.3-butylene gelicold dimethacrylate, 1
, 4-butylene glycol dimethacrylate, 1,6-
Hexane gelicol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2.2-bis(4-methacryloxyjethoxyphenyl)propane trimethacrylate compound trimethylolpropane trimethacrylate, trimethylol Among the above ethane trimethacrylates, it is particularly preferable to use divinylbenzene, ethylene glycol dimethacrylate, or trimethylolpropane trimethacrylate. In addition, these crosslinkable heptamers are 2
More than one species can also be used together.

In the present invention, it is necessary that the proportion of the crosslinking monomer be 10 to 55% by weight, preferably 20 to 55% by weight, and more preferably 30 to 55% by weight based on the total weight of the monomer.

When the proportion of the crosslinkable monomer is less than 10% by weight, the resulting polymer particles are less likely to be porous and have a collapsed shape or normal crosslinked particles. Note that the amount of crosslinking monomer here is based on a pure product excluding diluent and other impurities.

In the present invention, the polymerizable monomers used together with the above crosslinking monomers include aromatic monovinyl compounds such as styrene, α-methylstyrene, fluorostyrene, and vinylpyridine, vinyl cyanides such as acrylonitrile and methacrylate, vinylidene compounds, butyl acrylate, 2-ethylhexylethyl acrylate,
Acrylic acid ester monomers such as glycidyl acrylate, N,N-dimethylaminoethyl acrylate
Methacrylic acid ester monomers such as butyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, 2hydroxyethyl methacrylate, glycidyl acrylate, N,N-dimethylaminoethyl methacrylate, acrylic acid, methacrylic acid, maleic acid,
Mono- or dicarboxylic acids such as itaconic acid and acid anhydrides of dicarboxylic acids, amide yarn monomers such as acrylamide, methacrylamide, etc. can be used. In addition, conjugated double bond compounds such as butadiene and isoprene, vinyl ester compounds such as vinyl acetate, and 4-methyl-1-
Pentene and other α-olefin compounds can also be used. Two or more types of these may be used.

The halogen-containing monomer that can be used in the present invention is a compound that polymerizes by radicals and usually contains one or more radically polymerizable carbon-carbon double bonds in the molecule.

Specifically, the following structures can be mentioned.

(Left below) In the above formula, R is hydrogen or a methyl group, n is an integer from 0 to 5, and! is an integer from 0 to 10, Xm,
m' and Xm' may be the same or different and represent a chlorine or bromine substituent. Also, m, m', m
' is the number of missing halogen atoms and is an integer from 1 to 5.

Y is -CH2, CH2CH2- CH.

CH- CH.

N -O-, -C-.

N Specifically, chlorophenyl (meth)acrylate, dichlorophenyl (meth)acrylate, trichlorophenyl (meth)acrylate, bromophenyl (meth)acrylate, dibromophenyl (meth)acrylate,
Tribromophenyl (meth)acrylate, chlorophenoxyethylene (meth)acrylate, dichlorophenoxyethylene (meth)acrylate, trichlorophenoxyethylene (meth)acrylate, bromophenoxyethylene (meth)acrylate, dibromophenoxyethylene (meth)acrylate, tribromo Phenoxyethylene (meth)acrylate, 3.3-bis[4-(meth)acryloyloxy-3,5-dibromophenyl]pentane, 2.2-bis[4-(meth)acryloyloxy-3,5- Dibromophenylcobutane, 2,2-bis[
4-(meth)acroyloxy-3,5-dibromophenyl]propane, 4,4'-di(meth)acroyloxy-3,3', 5,5'-tetrabromodiphenylsulfone, 4,4' -di(meth)acroyloxy-3
,3',5.5'-tetrabromodiphenylmethane,4,4'-di(meth)acroyloxy-3,3'
, 5.5'-tetrabromodiphenyl ketone, 2.2
'-di(m-ri)acroyloxy-2,2', 3.
3'-5,5'6,6-octachlorodiphenyl ether, 4゜4'-di(meth)acryloyloxy-3,3'
5.5'-tetrabromodicyanomethane, 4°4'-di(meth)acroyl(ethyl)oxy3.3' 5.
5'-Tetrachlorodiphenyl and the reaction mixture of halogenated bisphenol and ethylene oxide are further reacted with di(meth)acrylic acid or di(meth)acrylic acid chloride, dichlorostyrene, trichlorostyrene, dichlorostyrene, Mention may be made of promostyrene, tribromostyrene, dichlorophenylmaleimide, tricumylophenylmaleimide, dibromophenylmaleimide, and tribromophenylmaleimide.

Among these compounds, brominated compounds are preferred for imparting a flame retardant effect. Particularly preferred compounds include 2
, 2-bis(4-methacroyloxy-3,5-dibromophenyl)propane, a compound obtained by adding about 2 moles of ethylene oxide to 1 mole of the above compound, dipromostyrene, tribromostyrene, tribromophenyl Maleimide is preferred from the viewpoint of flame retardant effect.

The amount of the halogen-containing monomer used is 30 to 90% by weight, preferably 30 to 80% by weight, and more preferably 30 to 70% by weight based on the total monomers. IX
If the proportion of the X rosin-containing monomer is less than 30% by weight, the resulting polymer particles will have insufficient flame retardancy.

The non-reactive solvent used in the present invention may be any solvent as long as it is absorbed by the seed polymer particles, is inert to radical polymerization, and does not inhibit monomer polymerization. Specific examples of non-reactive solvents include hydrocarbon compounds such as benzene, toluene, xylene, hexane, heptane, and cyclohexane, alcohols such as cyclohexanol and octatool, esters such as dibutyl phthalate and dioctyl phthalate, and cyclohexanone. Examples include ketones.

In general, using a non-reactive solvent with a high affinity for the polymerized polymer will yield porous particles with a small pore size, and using a non-reactive solvent with a low affinity with the polymerization polymer will yield porous particles with a large pore size. . Therefore, a non-reactive solvent is selected depending on the desired pore size.

For example, when the main component of the polymer is divinylbenzene, if toluene, which has good affinity, is used as a non-reactive solvent, porous particles with an average pore size of 50 to 100 will result, and as a non-reactive solvent, it will have a low affinity. When cyclohexanol is used, large porous particles with an average pore size of 500 to 2000 are obtained.

Note that it is also possible to use a mixture of two or more types of non-reactive solvents, and doing so is advantageous in controlling the affinity of the non-reactive solvents for the polymer.

The amount of non-reactive solvent used is preferably 0.05 to 70 times, more preferably 0.2 to 5 times the amount of polymerizable monomer used.
times, more preferably 0.3 to 3 times.

By adjusting the amount of non-reactive solvent, the porosity of the resulting porous particles can be controlled. When the amount of the non-reactive solvent is less than 0.05 times the amount of 7-mer, the particles do not become substantially porous particles but merely crosslinked particles. On the other hand, if the amount of non-reactive solvent exceeds 70 times the amount of monomer, it becomes difficult to maintain the shape of the porous particles.

Note that the amount of non-reactive solvent used also includes solvents or inert components contained as diluents or impurities in some crosslinking monomers.

In the present invention, the total amount of the polymerizable monomer and non-reactive solvent used is 2 to 2 parts by weight per 1 part by weight of the seed polymer particles.
18 parts by weight, preferably 5 to 15 parts by weight. If the amount used is less than 2 parts by weight, the ratio of the seed polymer particles is too large, resulting in the resulting polymer particles having a low degree of porosity and a distorted shape. In addition, the upper limit of the total amount of polymerizable monomer and non-reactive solvent is determined by the absorption capacity of the seed polymer particles, but especially when the polymer composition and molecular weight of the seed polymer particles are optimized, Although it is possible to add up to about 100 parts by weight, it is 18 parts by weight in the present invention.

If monomers and non-reactive solvents are added in excess of this upper limit and polymerized, the resulting polymer particles will not only be a mixture of coarse to fine particles, but the polymerization system will become unstable and produce a large amount of coagulum. Occur.

In the present invention, the monomer and non-reactive solvent can be added to the seed polymer particles all at once, or the monomer can be added in portions or continuously during polymerization. In the present invention, it is necessary for the seed polymer particles to absorb the 7-mer before polymerization begins and substantial crosslinking occurs in the seed polymer particles.

If the monomer is added after the middle stage of polymerization, the heptamer will not be absorbed into the seed polymer particles, so a large amount of fine particles will be produced, the polymerization stability will deteriorate, and the polymerization reaction cannot be maintained. Therefore, it is preferable to add all the monomers to the seed polymer particles before the start of polymerization, or to finish adding all the monomers before the polymerization yield reaches about 30%. In the present invention, it is particularly preferable to add a monomer and a non-reactive solvent to an aqueous dispersion of seed polymer particles and stir them before starting polymerization, and to start polymerization after both are absorbed by the seed polymer.

In the present invention, the amount of monomer used per 1 part by weight of the seed polymer particles is 0.1 to 17.7 parts by weight, preferably 0.5 to 15 parts by weight, and more preferably 1 to 12 parts by weight.

If the amount of this monomer used is less than 0.1 part by weight,
The final flame-retardant porous polymer particles obtained will have insufficient porosity due to the high proportion of soft seed polymer particles to the total, and phase separation within the seed polymer particles will cause the final The resulting flame-retardant porous polymer particles have an irregular shape, making it impossible to obtain truly spherical flame-retardant porous polymer particles.

In addition, if the amount of monomer used exceeds 17.7 parts by weight, the monomer absorption capacity of the seed polymer particles will be insufficient and the amount of monomer that will not be absorbed by the seed polymer particles will increase, making it difficult to control the particle size and allowing a wide range of Coarse particles with a particle size distribution will be generated (if an oil-soluble initiator is used), or a large amount of fine particles will be generated and the polymerization system will become unstable (if a water-soluble initiator is used).

In the present invention, the particle size of the flame-retardant porous polymer particles finally obtained can be controlled by adjusting the amount of seed polymer particles and the amount of monomer. Specifically, the weight of the seed polymer particles is expressed as WS
, the number average particle diameter is 3, the amount of monomer is M, and the amount of non-reactive solvent is S, the number average particle diameter of the flame-retardant porous polymer particles obtained can be estimated by the following formula, In practice, this can be achieved with relatively high accuracy.

The particle size of the flame-retardant porous polymer particles obtained by the present invention is
As mentioned above, it can be controlled by the particle size of the seed polymer particles used and the amounts of monomer and non-reactive solvent used.

In addition, the range of particle diameters obtained is determined by the particle diameter of the seed polymer particles used as seeds, but is usually 0.1 to 2 μm.
It can be easily synthesized within the range of m.

As mentioned earlier, it is difficult to obtain flame-retardant porous polymer particles in this range using conventional suspension polymerization methods, and it is necessary to classify and separate polymer particles synthesized by conventional methods or to separate monomers. Special, unproductive operations such as fine dispersion and polymerization using a high-pressure homogenizer were required.

In the present invention, a general water-soluble radical polymerization initiator or an oil-soluble radical polymerization initiator can be used as the polymerization initiator, but monomers that are not absorbed into the seed polymer particles may initiate polymerization in the aqueous phase. It is preferable to use a water-soluble polymerization initiator.

Examples of water-soluble radical initiators include potassium persulfate, sodium persulfate, cumene hydroperoxide, hydrogen peroxide, and redox initiators using a combination of these peroxides and a reducing agent.

The oil-soluble polymerization initiators used in the present invention include benzoyl peroxide, α,α-azobisisobutyronitrile, t-butylperoxy-2-ethylhexanoate, 3,5.5-1- Limethylhexanoyl peroxide and the like can be mentioned. In addition, in the polymerization reaction, it is preferable to add a small amount of a water-soluble polymerization inhibitor such as potassium dichromate, ferric chloride, or hydroquinone, since this can suppress the generation of fine particles.

In the polymerization reaction, a suspension protectant or a surfactant may be used to increase the stability of the polymerization reaction system.

However, if there is too much surfactant, fine particles may be generated and reduce polymerization stability.
It is preferable that the amount used is as small as possible. Particularly when polymerization is carried out using a water-soluble polymerization initiator, the concentration of the surfactant is preferably below the critical micelle formation concentration (C, M, C,).

On the other hand, when polymerizing using an oil-soluble polymerization initiator,
As long as the solubility of the monomer and oil-soluble polymerization initiator in water is sufficiently low, polymerization can be carried out without any problem even if the amount of surfactant used is C, M, C, or higher.

In the present invention, common surfactants can be used, and examples include anionic emulsifiers such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dialkylsulfosuccinate, and formalin condensate of naphthalenesulfonic acid. Can be done.

Furthermore, polyoxyethylene nonylphenyl ether,
It is also possible to use nonionic surfactants such as polyethylene glycol monostearate and sorbitan monostearate.

Preferred suspension protectants that can be used in the present invention include polyvinyl alcohol, carboxymethyl cellulose, sodium polyacrylate, and finely powdered inorganic compounds.

In the present invention, the most preferred polymerization initiator and stabilizer are used to obtain flame-retardant porous particles with a desired particle size and a narrow particle size distribution with good reproducibility while ensuring system stability during polymerization. The combination uses a water-soluble polymerization initiator as a polymerization initiator, and C,
M, C, concentration below and nearby concentration (specifically, C,
M.C.

0.3 to 1.0 times the concentration of surfactant. .

The flame-retardant porous polymer particles obtained in the present invention contain a non-reactive solvent inside the particles after polymerization. The non-reactive solvent inside the flame-retardant porous polymer particles can be removed by steam stripping, vacuum treatment, drying, extraction, etc.

The flame-retardant porous polymer particles obtained by the method of the invention have a high degree of crosslinking and therefore have extremely high hardness,
It is a flame-retardant porous polymer particle that has strength, heat resistance, and solvent resistance, and has a controlled and relatively fine particle size that has not been previously available. These flame-retardant porous polymer particles can be used in various fields by taking advantage of such properties.

Examples of uses of the flame-retardant halogen-containing porous polymer particles according to the present invention include column fillers for chromatography, particles for microcapsules, sustained release carriers, lubricants, spacers, and antiblocking agents.

Flowability improver for plastic pigments and powders.

Powder swelling agents, gloss modifiers 1 synthetic fiber additives, film additives, resin additives, paint compounding agents, filter media and filtration stimulants, particles for cosmetics, etc. Further, since the flame-retardant porous polymer particles of the present invention have flame retardancy, they can also be used as fillers for electronic and electrical parts.

[Example] The present invention will be described in detail below. In the following description, "part" and F%J represent 1% by weight.

Example 1 Styrene 98 parts Methacrylic acid 2 parts t-Dodecylmercaptan 10 parts Dodecylbenzenesulfonic acid 0.
05 parts sodium potassium persulfate 0.4 parts water
Capacity 2 for more than 200 parts of substance! The mixture was placed in a flask, and the temperature was raised to 70° C. in a nitrogen gas atmosphere while stirring, and polymerization was carried out for 6 hours. Thereby, seed polymer particles A were obtained with a polymerization yield of 98% and an average particle diameter of 0.43 μm and a standard deviation value of 0.015 μm per particle diameter. The particle diameter here is the average value of values measured for 100 polymer particles using transmission electron micrographs. This seed polymer particle A had 98% bone dissolved in toluene, and the molecular weight measured by gel permeation chromatography was: weight average molecular weight (Mw) = 5,500 number average molecular weight (M, ) - 3,000 .

Next, Seed Polymer Particles A (solid content equivalent) 10 parts Sodium lauryl sulfate 1.0 parts Potassium persulfate
0.5 part water
500 parts commercially available divinylbenzene (purity 55% product, remainder 25 parts monofunctional vinyl monomer) Tribromophenylmaleimide 25 parts cyclohexanol 50 parts or more of the substances were mixed and stirred at 30°C for 10 minutes to form the monomer into seed polymer particles. and cyclohexanol were absorbed. The concentration of sodium lauryl sulfate in water is 87% of the C, M, and C of the soap in water at 25°C.

Next, the temperature of the system was raised to 75°C and polymerization was carried out for 3 hours.
The polymerization yield was 98%, and the polymer coagulate remaining on the 200 mesh filter was 0.02% (based on polymer solid content), indicating that polymer particles with good polymerization stability were obtained.

A 1% aluminum sulfate aqueous solution (solid content 1 g) was added to this dispersion of polymer particles (100 g in terms of solid content), filtered, thoroughly washed with water to remove cyclohexanol, and then dried under reduced pressure to form a powder. of polymer particles were obtained.

When this polymer particle was observed with a scanning electron microscope, the average particle diameter was 1.20 μm, and the standard deviation value of the particle diameter was 0.
．． The particles were uniform in size of 0.042 μm.

Furthermore, when the particle surface was enlarged and observed, it was found that 0.05
Rough pores of ~0.1 μm were formed over the entire surface.

Further, when the specific surface area of this particle was measured using apparatuses B, E, and T, it was found to be a large value of 95 rrr/g.

Furthermore, in order to understand the thermal properties of the porous particles, thermobalance analysis was performed at a heating rate of 10°C/■In under a nitrogen gas atmosphere, and the temperature at which weight loss started was as high as 350°C. .

Furthermore, these polymer particles were flame retardant. The flame retardancy was evaluated at 30 parts by weight for 100 parts by weight of 1.2 polybutadiene (JSRRB 810 manufactured by Japan Synthetic Rubber).
A sheet was formed by filling parts by weight of porous polymer particles, and a combustion test was conducted according to UL-94. Note that the porous polymer particles prepared in Comparative Example 9 were used as a control sample, and a sample in which the burning rate was suppressed was set to 0. Samples with no inhibitory effect ×
And so.

Examples 2 to 4 and Comparative Examples 1 to 3 t in the production of seed polymer particles in Example 1
- The amount of dodecyl mercaptan used is 0 parts, 2 parts, 5 parts,
The same procedure was used as for seed polymer particles A except that the amounts were changed to 20 parts, 50 parts, and 100 parts, and the weight average molecular weight was 130.
,000.16,000. 9,000.3.200.
A total of 6 kinds of seed polymer particles B- of 800 and 300
G was synthesized. Flame-retardant porous polymer particles were produced in the same manner as in Example 1 except that each of these seed polymer particles was used.

Table 1 shows the ratio of polymerized coagulates and polymerization yields in each of the above polymerization reactions, as well as the average particle diameter, standard deviation value, specific surface area, and flame retardant evaluation of the obtained flame-retardant porous polymer particles. show.

As is clear from Table 1, in Comparative Example 1, the molecular weight of the seed polymer particles was too large, resulting in poor absorption of monomers and non-reactive solvents, resulting in low polymerization stability and poor reaction system stability during polymerization. It turned into a gel.

In Comparative Example 2, although polymerization was achieved, the amount of coagulated material produced was large, and the obtained polymer particles had a particle size of about 0.8 μm, which was close to the target particle size, and a particle size of about 0.05 μm. It is a mixture of three types of particles with particle diameters of 10 to 100 μm, which are produced by the direct polymerization of many microparticles of ~0.1 B m and monomer droplets that are not absorbed by the seed polymer particles, and the particle size distribution is extremely broad. It was something.

In Comparative Example 3, the molecular weight of the seed polymer particles was so small that absorption of monomers and non-reactive solvents was rather poor, resulting in low polymerization stability and gelation of the polymerization system.

Example 5 Seed polymer particles A of Example 1 were mixed with 10 parts as solid content, 5 parts of styrene and divinylbenzene (5 parts as monomers).
Polymerization was carried out in the same manner as in Example 1, except that 5 parts of 5% product) and 40 parts of tribromophenylmaleimide were used to obtain flame-retardant porous polymer particles.

Example 6 10 parts of seed polymer particles A of Example 1 as solid content, 20 parts of 4,4'-di(meth)acryloyloxy-3,3',5,5'-tetrabromodiphenylmethane and 4 as monomers. Polymerization was carried out in the same manner as in Example 1, except that 20 parts of -acroyloxy-4'-hydroxy-3,3',5,5'-tetrabromodiphenylmethane and 10 parts of divinylbenzene (55% product) were used. Flame retardant porous polymer particles were obtained.

Example 7 10 parts of seed polymer particles A of Example 1 as solid content, 5 parts of methyl methacrylate in place of styrene, 5 parts of ethylene glycol dimethacrylate and 40 parts of tribromophenyl maleimide in place of divinylbenzene. Polymerization was carried out in the same manner as in Example 1, except that nonflammable porous polymer particles were obtained.

Example 8.9 Seed polymer particles were produced in the same manner as in Example 1 except that the amount of sodium lauryl sulfate used in the production of seed polymer particles was changed to 0.8 parts and 2 parts, but the average particle diameter was 0.8 parts and 2 parts, respectively. Seed polymer particles H and I of 17 μm and o.ti μm were obtained.

Next, two kinds of flame-retardant porous polymer particles were obtained in the same manner as in Example 1 except that these seed polymer particles H and I were used.

As shown in Table 1, it was confirmed that according to the present invention, flame-retardant porous polymer particles with small and uniform diameters, which had been difficult to obtain in the past, could be obtained with good stability.

Examples 10-15. Comparative Examples 4 to 6 The procedure was carried out in the same manner as in Example 1, except that the seed polymer particles A of Example 1 were used as the seed polymer particles, and the number and amount of non-reactive solvents were changed as shown in Table 2. 6 per example
Three types of polymer particles were obtained for each seed and comparative example.

In Comparative Example 4, no non-reactive solvent was used, and the formation of pores in the polymer particles was insufficient.

In Comparative Example 5, there was an excessive amount of non-reactive solvent and a large amount of polymerized coagulum.

In Comparative Example 6, there was an excessive amount of non-reactive solvent, and the shape of the polymer particles could not be maintained during polymerization, resulting in crushed particles and a decrease in specific surface area.

In Example 13, toluene was used as a non-reactive solvent, and the polymer particles became good porous particles.
The pore size was very small, and no obvious pores were seen even when the particle surface was magnified using a scanning electron microscope. When the pore size distribution of this polymer particle was examined using a mercury intrusion porosimeter, it was found that the particles were porous particles with pores having a pore size of 20 to 100 pores, accounting for 80% of the total.

In the example of Example 1, polymerization was carried out using an oil-soluble initiator and a suspending protectant.

Seed polymer particles A (solid content) 6 parts polyvinyl alcohol 10 parts hydroquinone
0.05 part water
500 parts benzoyl peroxide 1 m<(used by mixing with monomer) Commercially available divinylbenzene (55% product) 25 parts tribromophenylmaleimide 25 parts toluene
50 parts of the above substances were mixed, stirred for 30 minutes, heated to 70°C, and polymerized for 4 hours.

As a result, the average particle size was 1.05 μm and the standard deviation value of 1 particle size was 0.05 at a polymerization yield of 98% and a polymerization coagulum of 0.15%.
Flame-retardant porous particles having a diameter of 5 μm and a specific surface area of 120 rrr/g were obtained. The results are shown in Table 3.

Examples 17 to 1, Comparative Example 7.8 The usage m (solid content) of seed polymer particles A was changed as shown in Table 3, and the total amount of polymerizable monomer and non-reactive solvent with respect to the seed polymer particles was Polymerization was carried out in the same manner as in Example 16, except that the ratio of
Two types of polymer particles were obtained for the comparative example.

In Example 17, since the amount of monomer and non-reactive solvent used for the seed polymer particles was slightly smaller, i)
The porous particles obtained were slightly distorted in shape.

In Comparative Example 7 and Comparative Example 8, the amount of monomer and non-reactive solvent used relative to the seed polymer particles was excessive, and in both cases, many new particles were formed by polymerization without being absorbed by the seed polymer particles. The particle size distribution was broad. Furthermore, in Comparative Example 8, not only the particle diameter n1 was broad as described above, but also the polymerization stability was low.

Comparative Example 9 10 parts of seed polymer particles A of Example 1 as solid content, 25 parts of styrene and divinylbenzene (as monomers)
Polymerization was carried out in the same manner as in Example 1, except that 25 parts of 55% product) were used.

In the case of this example, since a halogen-containing monomer was not used and the polymer was a hydrocarbon-based polymer, the expected flame retardant effect could not be obtained.

Comparative Example 10 Other than using 10 parts of seed polymer particles A of Example 1 as solid content, 22.5 parts of styrene, 22.5 parts of divinylbenzene (55% product) and 5 parts of tribromophenylmaleimide as monomers. Polymerization was carried out in the same manner as in Example 1 to obtain porous polymer particles.

However, in this example as well, the expected flame retardance could not be obtained because the amount of halogen-containing monomer used was small.

Comparative Example 11 10 parts of seed polymer particles A of Example 1 as solid content, 20 parts of styrene and divinylbenzene (as monomers)
55% product) 20 parts and tribromophenylmaleimide 10 parts
Porous polymer particles were obtained by polymerization in the same manner as in Example 1, except that part was used.

However, in this case as well, the expected flame retardance could not be obtained because the amount of halogen-containing monomer used was small.

[Effects of the Invention] By the method of the present invention, it has become possible to easily obtain porous polymer particles having small particle diameters of 2 μm or less, relatively uniform particle diameters, and flame retardancy, which has been difficult in the past.

According to this manufacturing method, the flame-retardant porous polymer particles obtained have a large specific surface area, and the pore diameter can be controlled relatively freely by selecting the non-reactive solvent used.

Furthermore, the flame-retardant porous polymer particles are highly crosslinked and have excellent heat resistance and solvent resistance.

Therefore, the flame-retardant porous polymer particles of the present invention can be used in applications that utilize the inner pores of microcapsule particles, sustained release carrier particles, etc., as well as particles for blending into resins, films, and fibers. It exhibits excellent properties expected in electrical and electronic parts and various other applications that require non-flammability, and is expected to be used successfully in new applications as well.

Claims (1)

[Claims] (1) Polystyrene equivalent weight average molecular weight is 500 to 10
,000, both a polymerizable monomer and a non-reactive solvent are added in an amount of 2 to 18 parts by weight per 1 part by weight of the seed polymer particles. A method of polymerizing by absorbing a non-reactive solvent, characterized in that the polymerizable monomer contains 10% by weight or more of a crosslinking monomer and 30% by weight or more of a halogen-containing monomer. Method of manufacturing particles.