JP2007177155A - Polyarylene sulfone microparticle, method for producing the same and dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide new polymer microparticles having high heat resistance and ≤50 μm particle diameter, which is highly desirable in fields of coating, adhesives and polymer alloy, and dispersion thereof. <P>SOLUTION: The polyarylene sulfone microparticles comprise ≥50 mass% structural unit represented by general formula (1) (R is hydrogen, a halogen or either one of an aliphatic substituent substituted by an arbitrary functional group in a permissible range of a valence and aliphatic substituent substituted with an aromatic substituent) and have ≤50 μm average particle diameter. A method for producing polyarylene sulfone microparticles comprises oxidizing polyarylene sulfide microparticles having ≤50 μm average particle diameter in the presence of an oxidizing agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to polyarylene sulfone fine particles, a method for producing the same, and a dispersion. Specifically, adhesives, paints, dispersants in printing inks, medical carriers, magnetic recording media, cosmetic base materials, plastic modifiers, chromatography carriers, additives for various materials such as interlayer insulating film materials In particular, the present invention relates to polyarylene sulfone fine particles that are excellent in dispersibility, heat resistance, and solvent resistance and that can be easily dispersed in a solvent, a method for producing the same, and a dispersion.

  Resin particles with high heat resistance are in great demand as heat-resistant additives with resin flexibility in the paint, adhesive materials, and polymer compound fields, but due to the technical limitations described below. Currently, it is extremely difficult to obtain.

  In this case, the heat resistance is required not to change the shape under high temperature conditions, and the glass transition temperature and melting point at which the fine particles are deformed are preferably 300 ° C. or higher.

  Generally, resin fine particles are roughly classified according to material, and fine particles obtained by polymerizing vinyl monomers, polycondensation fine particles, and the like can be given.

  In the former case, fine particles such as polystyrene and poly (methyl methacrylate) can be mentioned, but the glass transition temperature, which is particularly necessary for heat resistance, is not sufficient.

  In general, examples of the material having high heat resistance, that is, a glass transition temperature and a high melting point include polycondensation type fine particles, and specifically, resins such as polyarylene sulfide, polyimide, polyacetal, polycarbonate, and polyphenylene ether.

  In recent years, several methods shown below have been proposed as methods for obtaining these fine particles (Patent Documents 1 to 5).

  Patent Document 1 discloses a method for producing fine particles in which a crystalline polyester is heated, dissolved, and cooled and crystallized in a phase separation solvent in order to make fine particles of crystalline polyester, but the melting point is 300 ° C. or less. It cannot be said that it has sufficient heat resistance.

  Patent Document 2 discloses a method for producing polyamic acid fine particles and polyamide fine particles while using acid chloride and diamine as raw materials while advancing polymerization, but the method for producing fine particles while performing polycondensation is to react. There are problems such as the need for a process and the use of expensive chemicals, which is not an industrially advantageous method.

  The methods of Patent Documents 3 and 4 are methods for producing fine particles by dissolving in a crystalline polyester resin in an organic solvent at a high temperature, followed by cooling and mechanical pulverization, but have a special copolymer composition. Since it is used for polyester and is very expensive, it is difficult to say that it is highly practical.

Patent Document 5 describes an invention relating to a slurry composition using a resin powder having a structure similar to polyarylene sulfide. Although it is described that a resin powder having a structure similar to that of polyarylene sulfide can be used as a resin powder of 10 to 400 mesh (32 to 1700 μm), the melting point of these fine particles is not more than 300 ° C. Not satisfied.
JP-A-8-176310 JP-A-11-140181 Japanese Patent Laid-Open No. 2005-15589 JP 2005-84407 A JP-A-5-98158

  However, conventional heat-resistant resin fine particles do not necessarily have sufficient heat resistance, and development of resin-made fine particles having higher heat resistance has been widely demanded.

  An object of the present invention is to provide heat-resistant polyarylene sulfone fine particles that retain their shape even in an unprecedented temperature range, particularly in a temperature range exceeding 300 ° C., a method for producing the same, and a dispersion.

Thus, as a result of intensive studies by the present inventors, a polyarylene sulfone fine particle having a melting point exceeding 300 ° C., excellent in heat resistance, and having good dispersibility in a solvent, particularly water, and a simple method for obtaining the same are found. It was. That is, the present invention
(1) General formula (1)

(R represents hydrogen, halogen, an aliphatic substituent substituted with an arbitrary functional group within an allowable range of valence, or an aliphatic substituent substituted with an aromatic substituent). Polyarylene sulfone fine particles having a structural unit of 50% by mass or more and an average particle size of 50 μm or less,
(2) The polyarylene sulfone microparticle according to (1), wherein the polyarylene sulfone is poly (phenylene sulfone),
(3) A method for producing polyarylene sulfone, characterized in that polyarylene sulfide fine particles having an average particle size of 50 μm or less are used as a starting substrate and this is oxidized in the presence of an oxidizing agent.
(4) The method for producing polyarylene sulfone fine particles according to (3), wherein the oxidizing agent is an inorganic peroxide and / or an organic peroxide,
(5) The method for producing polyarylene sulfone fine particles according to (4), wherein the oxidizing agent is an oxidizing agent selected from at least one of performic acid, peracetic acid, trifluoroperacetic acid, and perpropionic acid. ,
(6) The polyarylene sulfone fine particles described in (1) or (2) or the polyarylene sulfone fine particles obtained by the production method described in (3) to (5) are dispersed in water containing a surfactant. Dispersion,
(7) A polyarylene sulfone fine particle according to (1) or (2), or a dispersion obtained by dispersing polyarylene sulfone fine particles obtained by the production method according to (3) to (5) in an organic solvent, is there.

  If the present invention is used, it can be used in a temperature range exceeding 300 ° C., which has been a problem until now. In a preferred embodiment, it can be used even at a high temperature of 350 ° C. or higher, and it has been heat resistant until now. Therefore, it is possible to easily synthesize highly heat-resistant resin fine particles that have been difficult to obtain in practical fields, and can be a very industrially useful material.

  The polyarylene sulfone in the present invention is represented by the following general formula (1)

(R represents hydrogen, halogen, an aliphatic substituent substituted with an arbitrary functional group within an allowable range of valence, or an aliphatic substituent substituted with an aromatic substituent). It is a homopolymer or copolymer having a repeating unit of 50% by mass or more, preferably 60% by mass or more, more preferably 80% by mass or more.

  Specific examples of the substituent R include a hydrogen atom, a halogen atom such as fluorine, chlorine, bromine and iodine, an aliphatic hydrocarbon having 1 to 4 carbon atoms, and preferably hydrogen, a methyl group, ethyl Group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, and more preferably hydrogen, methyl group, ethyl group, iso-propyl group, tert-butyl group. A butyl group is more preferred, and hydrogen and a methyl group are more preferred.

  Specific examples of the polyarylene sulfone in the present invention include poly-o-phenylene sulfone, poly-m-phenylene sulfone, poly-p-phenylene sulfone, poly-o-tolylene sulfone, poly- m-tolylene sulfone, poly-p-tolylene sulfone, poly-o-chlorophenylene sulfone, poly-m-chlorophenylene sulfone, poly-p-chlorophenylene sulfone, poly-o-fluorophenylene sulfone, Poly-m-fluorophenylene sulfone, poly-p-fluorophenylene sulfone and the like can be mentioned, among which poly-m-phenylene sulfone, poly-p-phenylene sulfone, poly-p-tolylene sulfone are preferable. More preferred are poly-p-phenylenesulfone It is.

  As long as it is a homopolymer or copolymer having the repeating unit represented by the general formula (1) as a main structural unit, the following formulas (2) to (4)

(Ar ′ represents an aromatic group.)
A small amount of branched bonds or crosslinks represented by

  The polyarylene sulfide in the present invention is the following general formula (5)

(R represents hydrogen, halogen, an aliphatic substituent substituted with an arbitrary functional group within an allowable range of valence, or an aliphatic substituent substituted with an aromatic substituent). It is a homopolymer or copolymer having 50% by mass or more of repeating units, preferably 70% by mass or more, particularly preferably 90% by mass or more.

  Specifically, the substituent R is a hydrogen atom, a halogen atom such as fluorine, chlorine, bromine or iodine, an aliphatic hydrocarbon having 1 to 4 carbon atoms, preferably a hydrogen, a methyl group, Examples thereof include an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, and a tert-butyl group, and more preferably hydrogen, a methyl group, an ethyl group, an iso-propyl group, a tert -A butyl group, more preferably hydrogen or a methyl group.

  Specific examples of the polyarylene sulfide include poly-o-phenylene sulfide, poly-m-phenylene sulfide, poly-p-phenylene sulfide, poly-o-tolylene sulfide, poly-m-tolylene sulfide, Poly-p-tolylene sulfide, poly-o-chlorophenylene sulfide, poly-m-chlorophenylene sulfide, poly-p-chlorophenylene sulfide, poly-o-fluorophenylene sulfide, poly-m-fluorophenylene sulfide, poly -P-fluorophenylene sulfide and the like are preferable, among which poly-m-phenylene sulfide, poly-p-phenylene sulfide, and poly-p-tolylene sulfide are preferable, and poly-m-phenylene sulfide is more preferable. - it is a polyphenylene sulfide.

  As long as it is a homopolymer or copolymer having a repeating unit represented by the general formula (5) as a main structural unit, the following formulas (6) to (8)

(Ar ′ represents an aromatic group.)
A small amount of branched bonds or crosslinks represented by

  The average particle diameter in the present invention means an average particle diameter measured by a laser diffraction particle size distribution meter based on the so-called Mie scattering / diffraction theory. Specifically, it means the average particle diameter calculated from the arithmetic average of the logarithm of the particle size obtained by analyzing the laser diffraction result according to Mie's theory.

An outline for obtaining polyarylene sulfone fine particles in the present invention is shown below.
(1) Make polyarylene sulfide.
(2) Make fine particles of polyarylene sulfide.
(3) Oxidize polyarylene sulfide fine particles.

  Below, along with the above outline, how to make polyarylene sulfone fine particles is shown in detail.

  Polyarylene sulfide can be synthesized by a known method, or a commercially available one can be used. Examples of the synthesis include a method of polymerizing a halogen aromatic compound and an alkali metal sulfide in an N-alkylamide solvent, and more specifically, Japanese Patent Publication No. 45-3368. And a method of increasing the degree of polymerization by heating the resulting polyphenylene sulfide having a relatively low molecular weight and a crosslinking agent such as a peroxide in an oxygen atmosphere. In addition, essentially linear and high molecular weight polyarylene sulfide is preferably used by the production method described in Japanese Patent Publication No. 52-12240.

  At this time, the molecular weight of polyarylene sulfide is not particularly limited as long as the shape of the particles is maintained, and the lower limit thereof is preferably 5,000 or more in terms of weight average molecular weight, and more preferably. Is 10,000 or more. About an upper limit, it is the range of the molecular weight which is an available range, and is usually 100,000 or less.

  Next, polyarylene sulfide particles are made. The polyarylene sulfide fine particles may be obtained by any method. For example, polyarylene sulfide fine particles may be prepared by using polyarylene sulfide in a pressure vessel, N-methylpyrrolidone, o-dichlorobenzene, 1- It can also be obtained by adding a solvent such as chloronaphthalene, dissolving under heating, and precipitating with cooling.

  In order to obtain polyarylene sulfide fine particles having a particle size of 50 μm or less by the above method, the heating temperature is 230 ° C. or higher, preferably 280 ° C. or higher. The upper limit is not particularly limited as long as the shape and physical properties of the polyarylene sulfide fine particles are not impaired, but it is usually 400 ° C. or lower, and preferably 350 ° C. or lower.

  In the case of producing by this method, it is possible to produce fine particles having a particle diameter of 10 μm or less.

  Moreover, as a density | concentration which melt | dissolves polyarylene sulfide in this case, 0.01 mass%-20 mass%, More preferably, it is 0.01 mass%-10 mass%, More preferably, it is 0.5 mass%-5 mass% % Range.

  Moreover, if it obtains by a conventionally well-known method, it can obtain by the method described in Unexamined-Japanese-Patent No. 10-273594. Specifically, (1) Polyarylene sulfide (a) such as polyphenylene sulfide (a) is added with one or more other thermoplastic polymers (b) (for example, polyolefin such as polypropylene) and melt-kneaded to obtain polyarylene sulfide (a ) Is a dispersed phase (island) having a desired particle size, and a resin composition having a sea-island structure in which the other polymer (b) is a matrix (sea) is obtained. (2) The resin composition is The arylene sulfide (a) is not dissolved but is washed with a solvent (c) and conditions so that the other polymer (b) is dissolved. (3) A method of removing the solvent (c) from the mixture of polyarylene sulfide (a) and solvent to obtain polyarylene sulfide fine particles.

  In the present invention, the polyarylene sulfide fine particles are fine particles based on polyarylene sulfide, which is a powder having an average particle size of 50 μm or less, preferably 25 μm or less, more preferably 10 μm or less, and its shape. May be in any form such as true sphere, oval sphere, flat shape, rock shape, confetti shape, and indefinite shape.

So far, the method for producing polyarylene sulfide and polyarylene sulfide fine particles shown above is an example, and the present invention is not limited thereto.
Continue to make polyarylene sulfone fine particles.

In order to produce polyarylene sulfone, it can be obtained by oxidizing the polyarylene sulfide fine particles obtained as described above in the presence of an oxidizing agent.
First, polyarylene sulfide fine particles are put into a reaction vessel, and a liquid necessary for an oxidation reaction is put therein.

  The liquid used in this reaction can be arbitrarily used as long as it is a liquid solvent containing an oxidizing agent and can maintain the form of the starting substrate. The liquid solvent may be either a general organic solvent alone or a mixed solvent, and may contain water or a solvent containing water alone. Specific examples of the liquid solvent include water, acetone, methanol, ethanol, acetonitrile, tetrahydrofuran, chloroform, N-methylpyrrolidone, ethyl acetate, acetic acid, trifluoroacetic acid, pyridine and the like. Among these, water, N -Methylpyrrolidone, ethyl acetate, acetic acid, trifluoroacetic acid, more preferably water, acetic acid, trifluoroacetic acid.

  As the oxidant used in this reaction, any one of inorganic peroxides and organic peroxides may be used, or a mixture thereof may be used. The peracid is preferably dissolved uniformly in the liquid solvent, and may be an equilibrium peracid formed from a mixture of hydrogen peroxide and acid.

Specific examples of peracids include inorganic peroxides such as hydrogen peroxide, urea peroxide, persulfate, perborate, percarbonate, performic acid, peracetic acid, trifluoroperacetic acid, perpropionic acid, Examples include organic peroxides such as perbutyric acid, perbenzoic acid, and m-chloroperbenzoic acid. Among these, preferred are formic acid, peracetic acid, trifluoroperacetic acid, and perpropionic acid. Acetic acid and trifluoroperacetic acid. These can be used alone or in combination of two or more.
Further, the concentration of peracid is important for safety management in an industrial production method. In this oxidation reaction system, the concentration of peracid in the liquid is preferably 10% by mass or less, and more preferably 3 to 10% by mass. . A good reaction result can be obtained at a concentration within this range, and a highly safe process can be constructed. If it is higher than this, its stability and safety are easily affected by temperature, and in particular, a high concentration peracid of 20 to 40% by mass is difficult to manage because of its stability and process safety.
This oxidation treatment is performed at a temperature below the boiling point of the liquid used. When the temperature is higher than the boiling point, the system is pressurized, and the decomposition of the oxidant is promoted, complicated equipment is used, and it is not preferable from the viewpoint of safety. The specific reaction temperature is preferably between 0 ° C. and 80 ° C., more preferably between about room temperature and 60 ° C. It gives good reaction results at temperatures in this range.

  Moreover, an additive can also be added as needed. In order to accelerate this reaction, it is better to add inorganic mineral acid. In this case, the inorganic mineral acid is at least one selected from sulfuric acid, hydrochloric acid, nitric acid, and perchloric acid, and is preferably sulfuric acid.

  Moreover, in order to perform this oxidation treatment, the mixed solution may or may not be stirred, but stirring is preferable because the reaction proceeds more uniformly.

  This reaction is completed by raising the temperature to the above temperature and then maintaining the mixed solution for a while. The time at this time is in the range of 10 minutes to 10 hours, preferably in the range of 10 minutes to 6 hours, and more preferably in the range of 20 minutes to 2 hours.

  When carried out in this range, the desired reaction is completed.

  After the reaction is completed, the polyarylene sulfone fine particles are recovered from the reaction solution.

  At this time, as a method of recovery, it can be recovered by performing a conventionally known solid-liquid separation and drying if necessary. Specific examples include filtration, centrifugation, centrifugal filtration, spray drying, decantation, and the like.

  As described above, polyarylene sulfone fine particles are obtained.

  Next, the polyarylene sulfone fine particle dispersion will be described.

  Basically, a polyarylene sulfone fine particle dispersion is obtained by dispersing the obtained polyarylene sulfone fine particles in a dispersion medium.

  In this case, if it is exemplified as a dispersion medium, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, cyclopentane, decane, dodecane, tridecane, tetradecane, benzene, toluene, xylene, 2 -Aromatic hydrocarbon solvents such as methylnaphthalene, ester solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, butyl butyrate, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1, Halogen solvents such as 1-trichloroethane, chlorobenzene, o-dichlorobenzene, p-dichlorobenzene, 2,6-dichlorotoluene, 1-chloronaphthalene, hexafluoroisopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl Polar solvents such as ketone solvents such as tilketone, alcohol solvents such as methanol, ethanol, isopropanol, n-propanol, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, trimethyl phosphoric acid, N-methylpyrrolidinone A solvent, at least one solvent selected from ether solvents such as diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme, dimethoxyethane, and water, and water can be exemplified, but water is most preferable from the environmental and safety viewpoints.

  At this time, a surfactant may be added in order to improve dispersibility in water.

  Examples of the surfactant include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant. Examples of the anionic surfactant include fatty acid sodium, fatty acid potassium, and alkylbenzene sulfone. Sodium acid, sodium alkyl sulfate, sodium alkyl sulfonate, sodium alkyl ether sulfate, monoalkyl phosphate, polyoxyethylene alkyl ether sodium phosphate, sodium fatty acid ester sulfonate, sodium fatty acid ester sulfate, Examples include sodium rosamide sulfate and sodium fatty acid amide sulfonate.

  Examples of the cationic surfactant include alkyl methyl ammonium chloride, alkyl trimethyl ammonium chloride, dialkyl dimethyl ammonium chloride, alkyl dimethyl benzyl ammonium chloride, and alkyl pyridinium chloride.

  Examples of zwitterionic surfactants include alkylaminocarboxylates, carboxybetaines, alkylbetaines, sulfobetaines, and phosphobetaines.

  Nonionic surfactants include sucrose fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene lanolin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycol mono fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene Examples thereof include oxyalkyl ethers, fatty acid alkanolamides, fatty acid monoethanolamides, fatty acid diethanolamides, fatty acid triethanolamides, polyoxyethylene fatty acid amides, isopropanolamides, alkylamine oxides, and polyoxyethylene amines.

  The alkyl referred to here is, for example, a straight chain saturated hydrocarbon group, straight chain unsaturated hydrocarbon group, branched saturated hydrocarbon group or branched unsaturated hydrocarbon having 2 to 30 carbon atoms. Groups.

  The amount of these surfactants added is usually in the range of 0.01 to 100 parts by weight, preferably in the range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the dispersion medium. More preferably, it is the range of 1-10 mass parts. By using the surfactant in an amount within this range, the polyarylene sulfone fine particles can be uniformly dispersed in the dispersion medium very efficiently.

  The polyarylene sulfone fine particles are added in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass of the dispersion medium and 100 parts by mass with respect to the total amount of the dispersion medium and the surfactant when the surfactant is added. It is preferable that it is the range of these.

  In order to sufficiently disperse, the dispersion obtained above may be supplied with physical energy such as heating, ultrasonic irradiation, laser irradiation, and microwave irradiation.

  The polyarylene sulfone fine particle dispersion obtained in this way may also contain a precipitate in some cases. In that case, the precipitation part and the dispersion part may be used separately. When only the dispersion liquid is obtained, the precipitation part and the dispersion part may be separated. For this purpose, decantation, filtration, or the like may be performed. In addition, when a finer particle size is necessary, centrifugation or the like is performed, and the larger particle size is completely settled, followed by decantation or filtration to remove the precipitated portion.

  The polyarylene sulfone fine particles and the polyarylene sulfone dispersion liquid thus obtained are useful in the fields of paint, adhesion, and polymer compound.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this. The manufacturer grades of the reagents used here correspond to the first level.

  Moreover, in order to measure physical properties, the following equipment was used.

<Differential thermal scanning calorimeter: DSC>
Model name: Seiko Instruments Robot DSC was used for measurement with the following temperature program.
Measurement temperature program conditions: 30 ° C. → (20 ° C./min)→350° C.

<Differential thermogravimetry: TGA>
Model name: Seiko Instruments TG / DTA 200 was used, and the measurement was performed with the following temperature program.
Measurement temperature program conditions: 50 ° C. → (20 ° C./min)→650° C.

<Particle size distribution measurement>
The average particle size of the particles was measured using a diffraction particle size distribution meter (SALD-2100, manufactured by Shimadzu Corporation).

(Reference Example 1) PPS fine particle preparation method In a 50 cc pressure vessel, 100 mg of polyphenylene sulfide (manufactured by Toray Industries Inc., grade name M3910, average particle size 50 μm) and 10 g of N-methylpyrrolidinone (manufactured by Kanto Chemical Co., Inc.) as a solvent are added After sealing under nitrogen, the temperature was raised to 320 ° C. After confirming that the temperature rose to 320 ° C., the state was maintained while stirring for 30 minutes, and then the pressure vessel was cooled with ice water.

  After cooling to near room temperature, the mixed solution was taken out from the pressure vessel and subjected to suction filtration using 5C filter paper to obtain polyarylene sulfide fine particles. This fine particle was measured with a laser diffraction particle size distribution analyzer (SALD-2100, manufactured by Shimadzu Corporation, dispersion medium: 0.5 mass% aqueous solution of TirotonX-100 (manufactured by Aldrich)), and the logarithm of the particle size analyzed according to Mie's theory When the average particle size was calculated, the average particle size was found to be 7.26 μm.

  Further, the filtrate was centrifuged at a speed of 6000 rpm, and decantation was performed to collect finer particles.

  When the average particle size of the fine particles was measured in the same manner, the average particle size was 1.6 μm, and fine particles with a particle size smaller than that of the fine particles were obtained. It was found that fine polyphenylene sulfide fine particles can be obtained by the present invention.

Example 1
20.0 g of a peracetic acid solution (manufactured by Mitsubishi Gas Chemical Company) adjusted to 9% by mass with acetic acid (manufactured by Kanto Chemical Co., Inc.) was charged into the reaction vessel, and stirred at 60 ° C. Next, 70.6 mg (average particle size 7.26 μm) of poly-p-phenylene sulfide (PPS) fine particles obtained in Reference Example 1 were immersed in the reaction solution and reacted at 60 ° C. for 3 hours. The obtained mixed solution was subjected to suction filtration. When dried at 60 ° C. under vacuum for 12 hours, 91.6 mg of poly-p-phenylene sulfoxide (PPSO) fine particles were obtained. When the fine particles were measured with a differential scanning calorimeter (DSC), it was found that the melting point (285 ° C.) of PPS disappeared and became infusible and high heat-resistant fine particles.

  Further, when thermogravimetry was performed on the fine particles, the 5% weight loss temperature was 450 ° C.

(Example 2) Evaluation of heat resistance of fine particles In order to evaluate heat resistance at 300 ° C, fine particles were placed on a hot plate, and the property change was observed with a microscope.

  In addition, comprehensive evaluation is a comprehensive evaluation of decomposition and shape stability in a high temperature state, the standard is: ○: there is no decomposition behavior at 300 ℃, the shape is visually stable, ×: Decomposition behavior at 300 ° C., or the shape in the sight was not stable, and it was assumed that it had melted or started melting.

  From the above results, it was shown that the heat resistance of the fine particles in the present invention is high.

(Example 2)
50 mg of the poly-p-phenylene sulfoxide fine particles obtained in Example 1 were added to 50 g of 5% polyoxyethylene (10) isooctyl cyclohexyl ether (trade name: Triton X-100 Aldrich aqueous solution, and subjected to ultrasonic irradiation for 2 minutes. As a result, a good dispersion was obtained.

  The polyarylene sulfone fine particles obtained in the present invention are fine and fine particles, and are excellent in heat resistance and chemical resistance. It can be widely used in applications such as paints, dispersants in printing inks, medical carriers, magnetic recording media, cosmetic base materials, plastic modifiers, chromatographic carriers, and correlated insulating film materials.

  In addition, the production method of the present invention is a production method for obtaining polyarylene sulfide fine particles by a simple and efficient method and an industrially excellent method using a reagent that is easily industrially available.

Claims (7)

General formula (1)

(R represents hydrogen, halogen, an aliphatic substituent substituted with an arbitrary functional group within an allowable range of valence, or an aliphatic substituent substituted with an aromatic substituent). Polyarylene sulfone fine particles having a structural unit of 50% by mass or more and an average particle size of 50 μm or less. 2. The polyarylene sulfone fine particles according to claim 1, wherein the polyarylene sulfone is poly (phenylene sulfone). A process for producing polyarylene sulfide fine particles, characterized in that polyarylene sulfide fine particles having an average particle size of 50 μm or less are used as a starting substrate and oxidized in the presence of an oxidizing agent. The method for producing polyarylene sulfone fine particles according to claim 3, wherein the oxidizing agent is an inorganic peroxide and / or an organic peroxide. The method for producing polyarylene sulfone microparticles according to claim 4, wherein the oxidizing agent is an oxidizing agent selected from at least one of performic acid, peracetic acid, trifluoroperacetic acid, and perpropionic acid. A dispersion in which the polyarylene sulfone fine particles according to claim 1 or 2 or the polyarylene sulfone fine particles obtained by the production method according to any one of claims 3 to 5 are dispersed in water containing a surfactant. A dispersion comprising the polyarylene sulfone fine particles according to claim 1 or 2 or the polyarylene sulfone fine particles obtained by the production method according to any one of claims 3 to 5 dispersed in an organic solvent.