JP2017061607A - Polyphenylene sulfide fine particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyphenylene sulfide fine particle which can be re-dispersed in medium.SOLUTION: In a polyphenylene sulfide fine particle, on the surface of a raw material polyphenylene sulfide fine particle comprising polyphenylene sulfide, adsorbed is a cationic polymer dispersant 0.1 pts.mass-30 pts.mass per the raw material polyphenylene sulfide fine particle 100 pts.mass, and a percentage content of a volatile component in the polyphenylene sulfide fine particle is less than 50 mass%.SELECTED DRAWING: None

Description

  The present invention relates to polyphenylene sulfide fine particles having a dispersant adsorbed on the surface of the fine particles. More particularly, the present invention relates to polyphenylene sulfide fine particles adsorbed with a cationic polymer dispersant and redispersible in a medium.

  Polyphenylene sulfide (hereinafter sometimes abbreviated as PPS) resin has properties suitable as engineering plastics such as excellent heat resistance, chemical resistance, solvent resistance, and electrical insulation. Therefore, PPS resin is an additive to modifiers of various sliding parts such as oil and grease, mainly in injection molding and extrusion molding, various parts in the fields of electrical materials, machinery and automobiles. Is used.

  In particular, as an application that takes advantage of the properties of PPS resin such as electrical insulation and chemical resistance, a PPS resin coating layer is applied to the surface of the member to form an adhesive layer, and PPS resin is used as a modifier for various oils and greases. Applications for addition are known. In such an application, it is often handled as a dispersion liquid in which a PPS resin is dispersed in a solvent because of the ease of operation.

  The dispersion of the PPS resin is obtained by making the PPS resin into the form of fine particles and dispersing the PPS fine particles in a desired solvent. As a technique for obtaining polymer fine particles, there are a bottom-up type in which monomers are polymerized into a polymer fine particle form such as emulsion polymerization and suspension polymerization, and a top-down type in which a resin polymer is refined and processed by mechanical pulverization or the like. , Can be broadly divided. Fine particles of PPS resin cannot be obtained by emulsion polymerization or suspension polymerization, and can be obtained in a top-down manner in which an already polymerized PPS polymer is processed into a fine particle form.

  Furthermore, in recent years, several methods shown below have been proposed as methods for obtaining PPS fine particles or PPS fine particle dispersions.

  In Patent Document 1, a PPS resin and a thermoplastic polymer other than that are melt-kneaded to form a sea-island structure resin composition in which the PPS resin is an island and another thermoplastic polymer is the sea, and then the sea phase is dissolved and washed Thus, spherical PPS resin fine particles are obtained.

  In addition, a method for producing PPS fine particles using precipitation by cooling is known. In Patent Document 2, after dissolving a PPS resin polymer in a solvent, the solution is cooled to cool micron-sized PPS fine particles. Have gained. In Patent Documents 3 and 4, a solution in which a PPS resin is dissolved is heated and pressurized, and the solution is ejected into a poor solvent through a nozzle and rapidly cooled to produce submicron-sized PPS fine particles. A method is disclosed in which after the precipitation, the solvent is replaced with a dispersion medium, and a polymer dispersant is added to obtain a dispersion.

  In Patent Document 5, after dissolving and mixing a PPS resin, a polymer different from the PPS resin, and an organic solvent, a solution phase containing PPS as a main component and a solution phase containing a polymer different from PPS resin as a main component. In a system in which two phases are separated, a method of producing PPS resin fine particles by stirring to form an emulsion and then contacting a poor solvent of the PPS resin is shown.

JP-A-10-273594 JP 2007-154166 A JP 2011-122108 A JP 2012-177010 A International Publication No. 2012/043509

  In order to use the PPS fine particle as a dispersion having high versatility in handling, it is desired to be a PPS fine particle having excellent dispersibility in various solvents.

  However, the fine particles of Patent Document 1 do not show a technical idea that contributes to dispersibility, and the obtained fine particles have low dispersibility in a solvent and cannot be used in an actual process.

  In Patent Document 2, the fine particles obtained by cooling the PPS solution are solid-liquid separated and then added to a solvent containing a surfactant to form a dispersion of fine PPS particles. However, according to the study by the inventors, a low molecular weight dispersant such as a surfactant described in Patent Document 2 is not suitable for stabilizing the dispersion of particles having a particle size of submicron to several μm. The dispersibility of the obtained PPS fine particles is low. When dispersing PPS fine particles obtained by cooling in an organic solvent, it is necessary to replace the solvent with a large amount of solvent. In particular, to replace with a non-aqueous solvent, it is necessary to replace the solvent in multiple steps in terms of solubility. This is not economically and environmentally favorable.

  Patent Documents 3 and 4 disclose a method for producing a PPS fine particle dispersion containing a polymer dispersant, and both methods produce a dispersion using water or a water-soluble alcohol as a dispersion medium. It is a method, and a specific method for obtaining a dispersion using another solvent as a dispersion medium is not disclosed. In Patent Documents 3 and 4, in order to obtain a dispersion using an arbitrary solvent as a dispersion medium, the PPS fine particles are solid-liquid separated from the dispersion to form a wet cake, and the solvent contained in the wet cake is converted into a desired dispersion medium. Although a method for replacing the solvent is suggested, the methods described in these documents are not industrially advantageous methods because the available dispersion media are limited. Patent Documents 3 and 4 require that the PPS fine particles contain a solvent, and a method of taking the fine particles as a powder from the dispersion and redispersing it in a desired solvent to obtain a dispersion. There is no description or suggestion regarding.

  Further, according to the study by the inventors, in the methods disclosed in Patent Documents 3 and 4, the amount of the polymer dispersant contained in the dispersion is excessive. Further, there is no chemical mechanism for immobilizing the dispersant on the surface of the PPS fine particles, and the dispersant is present in the dispersion in a free state. Therefore, for example, when the dispersion is mixed with another composition, the added polymer dispersant is highly likely to cause contamination, which is not preferable in practice.

  Patent Document 5 describes a polymer corresponding to a polymer dispersant as a polymer different from a PPS resin. However, the method for producing PPS fine particles disclosed in Patent Document 5 is a method using the phase separation phenomenon of a polymer solution, and it is difficult to think that a polymer corresponding to a polymer dispersant exhibits an interaction with the surface of the PPS fine particles. . As a result of the study by the inventors, the dispersibility of PPS fine particles obtained by the method described in Patent Document 5 in various solvents was insufficient.

  On the other hand, PPS fine particles can be used in a form dispersed in all solvents and media including water and alcohol and other polar solvents as well as nonpolar solvents in addition to water and alcohol for industrial applications utilizing its chemical resistance. Is desired. When a dispersant is used, it is desirable that the dispersant is a minimum amount because it can cause contamination, and that the dispersant is immobilized on the fine particle surface by interaction. For this purpose, PPS fine particles, which are powders of PPS fine particles in which a dispersant is adsorbed on the surface of the fine particles and can be re-dispersed in a target solvent or medium, are strongly desired. The fine particles did not satisfy these characteristics.

  An object of the present invention is to provide polyphenylene sulfide fine particles that can be redispersed in a medium at a practically usable level.

  As a result of intensive studies by the present inventors in order to achieve the above object, the following invention has been achieved.

[1] Polyphenylene sulfide fine particles, and 0.1 to 30 parts by mass of a cationic polymer dispersant per 100 parts by mass of the raw polyphenylene sulfide fine particles are adsorbed on the surface of the raw polyphenylene sulfide fine particles containing polyphenylene sulfide. And the volatile component content of the polyphenylene sulfide fine particles, wherein the volatilization rate is defined as a weight reduction rate when 10 mg of the polyphenylene sulfide fine particles are heated from 20 ° C. to 200 ° C. in a nitrogen atmosphere. Polyphenylene sulfide fine particles, wherein the component content is less than 50% by mass.

[2] The polyphenylene sulfide fine particles according to [1], wherein the cationic polymer dispersant is a polyalkylene polyamine.

[3] The polyphenylene sulfide fine particles according to [1] or [2], wherein the polyphenylene sulfide fine particles have an average primary particle diameter of 0.05 μm to 1 μm.

[4] The polyphenylene sulfide fine particles according to any one of [1] to [3], wherein the sphericity of the polyphenylene sulfide fine particles is 80 or more.

[5] The polyphenylene sulfide fine particles according to any one of [1] to [4], wherein an anionic surfactant is further adsorbed on the surface of the raw material polyphenylene sulfide fine particles.

[6] The polyphenylene sulfide fine particles according to [5], wherein the anionic surfactant is one or more surfactants selected from fatty acids and polyoxyalkylene alkyl ether phosphates.

[7] The polyphenylene as described in [5] or [6], wherein the adsorption amount of the anionic surfactant is 0.1 to 50 parts by mass per 100 parts by mass of the raw polyphenylene sulfide fine particles. Sulfide fine particles.

[8] The method for producing polyphenylene sulfide fine particles according to any one of [1] to [4], wherein the cationic polymer dispersion is dispersed in the raw material polyphenylene sulfide fine particles in the first solvent (A). A first step of contacting the agent, and a second step of removing the first solvent (A) from the raw polyphenylene sulfide fine particles contacted with the cationic polymer dispersant after the first step. And a method for producing polyphenylene sulfide fine particles.

[9] The method for producing polyphenylene sulfide fine particles according to any one of [5] to [7], wherein the cationic polymer is added to the raw polyphenylene sulfide fine particles in the second solvent (B). A third step of bringing a dispersant into contact with the anionic surfactant; and after the third step, from the raw polyphenylene sulfide fine particles having been brought into contact with the cationic polymer dispersant and the anionic surfactant. And a fourth step of removing the second solvent (B). A method for producing polyphenylene sulfide fine particles, comprising:

[10] The method for producing the polyphenylene sulfide fine particles according to any one of [5] to [7], wherein the raw material polyphenylene sulfide fine particles are added to the raw material polyphenylene sulfide fine particles in the first solvent (A). A first step of contacting a molecular dispersant; and a second step of removing the first solvent (A) from the raw polyphenylene sulfide fine particles contacted with the cationic polymer dispersant after the first step. And before or after the second step, the anionic surfactant is brought into contact with the raw material polyphenylene sulfide fine particles contacted with the cationic polymer dispersant in the third solvent (C). The raw material polyphenylene sulfide in which the cationic polymer dispersant and the anionic surfactant are contacted after the fifth step and the fifth step. Sixth step and, polyphenylene sulfide microparticle production method which comprises a removing the from id particles third solvent (C).

[11] A polyphenylene sulfide fine particle dispersion in which the polyphenylene sulfide fine particles according to any one of [1] to [7] are dispersed in a dispersion medium.

[12] The polyphenylene sulfide fine particle dispersion according to [11], wherein the concentration of the polyphenylene sulfide fine particles in the dispersion is 0.01 to 80 parts by mass per 100 parts by mass of the dispersion.

[13] The polyphenylene sulfide fine particle dispersion described in [11] or [12], wherein the volume average particle diameter of the polyphenylene sulfide fine particles in the dispersion is 0.05 μm to 10 μm.

[14] A resin composition containing the polyphenylene sulfide fine particles according to any one of [1] to [7].

According to the present invention, it is possible to obtain PPS fine particles that can be redispersed in a medium at a practically usable level, which has been difficult to manufacture with the prior art.
The PPS fine particle of the present invention is a PPS fine particle having a cationic polymer dispersant adsorbed on its surface, and is a fine particle containing almost no volatile component such as a solvent. It is possible to make a dispersion by simply putting it in the desired medium and redispersing it, and the cationic polymer dispersant adsorbed on the surface of the fine particles has a high affinity for the medium and a high steric barrier between the fine particles. Thus, aggregation of the fine particles can be suppressed, and the fine particles can be dispersed in the medium at a higher concentration. Further, the PPS fine particles of the present invention are redispersible in the medium at the same time that the cationic polymer dispersant adsorbed on the fine particle surface is bonded to the fine particle surface by electrostatic interaction. Even if dispersed, excess dispersant does not cause adverse effects on the product due to contamination.

It is explanatory drawing showing an adsorption isotherm.

In the present specification, the following terms are defined as follows.
Raw material PPS resin: PPS resin constituting the following raw material PPS fine particles.
Raw material PPS fine particles: PPS fine particles made of a raw material PPS resin and used as a material for the following PPS-C fine particles or PPS-CA fine particles.
PPS-C fine particles: PPS fine particles according to an embodiment of the present invention, wherein the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles.
PPS-C-A fine particles: PPS fine particles according to an embodiment of the present invention, wherein PPS fine particles (PPS-C fine particles and PPS fine particles in which a cationic polymer dispersant and an anionic surfactant are adsorbed on the surface of raw material PPS fine particles are used. -C-A fine particles may be collectively referred to as dispersant-adsorbed PPS fine particles).

<Raw material PPS resin>
The polyphenylene sulfide resin in the embodiment of the present invention is a homopolymer or copolymer having a repeating unit represented by the formula (1) as a main structural unit.

Ar in the general formula (1) is an aromatic group. Examples of Ar include aromatic groups represented by the following formulas (2) to (4). Here, R ¹ and R ² are each independently a group selected from hydrogen, an alkyl group, an alkoxyl group, and a halogen group.

As long as the above repeating unit is a main constituent unit, it may contain a branched bond or a cross-linked bond represented by formula (5) or the like, or a copolymer component represented by formulas (6) to (14). Here, R ¹ and R ² are each independently a substituent selected from hydrogen, an alkyl group, an alkoxyl group, and a halogen group.

  A PPS resin particularly preferably used is PPS containing 80 mol% or more of p-phenylene sulfide units represented by the formula (15) as the main structural unit of the polymer.

  In addition to the p-phenylene sulfide unit represented by the formula (15), a resin obtained by copolymerizing an m-phenylene sulfide unit and / or an o-phenylene sulfide unit may be used as the PPS resin.

  The molecular weight of the raw material PPS resin is not particularly limited, but since the PPS resin tends to take the form of fine particles, the weight average molecular weight Mw is preferably 10,000 or more, and 20,000 or more. More preferably, those of 30,000 or more are further preferred, those of 40,000 or more are particularly preferred, and those of 50,000 or more are extremely preferred. Moreover, as the upper limit, 250,000 or less which is the upper limit of the molecular weight of the PPS resin obtained by a known method is preferable, 200,000 or less is more preferable, 150,000 or less is more preferable, and 125,000 or less is particularly preferable. 100,000 or less is remarkably preferable.

  The molecular weight distribution state of the raw material PPS resin, that is, the molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is preferably 2-10. More preferred are those of 4-6.

  Here, the weight average molecular weight Mw and the number average molecular weight Mn refer to values measured by gel permeation chromatography (GPC) using water as a solvent and calculated in terms of polystyrene.

  The raw material PPS resin used in the embodiment of the present invention is not particularly limited as long as the raw material PPS fine particles made of the raw material PPS resin exhibit a surface potential as described later and the PPS fine particles of the embodiment of the present invention can be obtained. However, it is preferable that it contains an acid terminal or a metal salt thereof as a molecular terminal. The acid terminal or the terminal containing a metal salt thereof is a molecular terminal derived from the raw material PPS resin production method. Specific examples of such molecular ends include a carboxylic acid end, a sodium carboxylate end, or a calcium carboxylate end, and a carboxylic acid end is more preferable. By using such a raw material PPS resin, it is considered that the raw material PPS fine particles have carboxyl groups on the surface of the fine particles, and the raw material PPS fine particles exhibit a negative surface potential in the liquid as described later.

<Raw material PPS fine particles>
About the raw material PPS microparticles | fine-particles which consist of said raw material PPS resin, the PPS microparticles | fine-particles of embodiment of this invention are obtained by making a cationic polymer dispersing agent (or also anionic surfactant) adsorb | suck to the microparticle surface. The raw material PPS fine particles used in the embodiment of the present invention may be PPS fine particles obtained by any manufacturing method as long as it is made of the raw material PPS resin.

  The average primary particle diameter of the PPS fine particles (dispersant-adsorbed PPS fine particles) of the embodiment of the present invention is determined by the average primary particle diameter of the raw material PPS fine particles used. Even if the cationic polymer dispersant or the anionic surfactant is adsorbed on the surface of the raw material PPS fine particles, the particle diameter measured by the measurement method described later is not substantially affected. The primary particle diameter has the same value as the average primary particle diameter of the raw material PPS fine particles. The average primary particle size of the dispersant-adsorbed PPS fine particles and the raw material PPS fine particles according to the embodiment of the present invention is preferably 0.05 μm to 1 μm. The lower limit is preferably 0.1 μm or more, more preferably 0.125 μm or more, further preferably 0.15 μm or more, particularly preferably 0.175 μm or more, and particularly preferably 0.2 μm or more. The upper limit is preferably 0.8 μm or less, more preferably 0.7 μm or less, particularly preferably 0.6 μm or less, and particularly preferably 0.5 μm or less.

  If the average primary particle size is too small, for example, less than 0.05 μm, the particle size becomes smaller than the particle size range suitable for stabilizing the dispersion using a cationic polymer dispersant, and the polymer dispersion When the size of the agent is increased with respect to the particle size, it is not preferable because crosslinking aggregation in which the polymer dispersant is adsorbed over a plurality of fine particles tends to occur. On the other hand, if the average primary particle size is too large, for example, if it exceeds 1 μm, the inertial force of the fine particles becomes too large, and thus the fine particles are controlled to gravity settle even if the cationic polymer dispersant is adsorbed. This is difficult and practically undesirable for the dispersant-adsorbed PPS fine particles of the embodiment of the present invention.

  The average primary particle diameter of the dispersant-adsorbed PPS fine particles and the raw material PPS fine particles (hereinafter also simply referred to as fine particles) in the embodiment of the present invention is a particle measured from an image observed with a scanning electron microscope (FE-SEM). The average value of diameters. Specifically, observation is performed with a magnification and a field of view so that two or more and less than 100 particles appear in one FE-SEM image, and the diameter (particle diameter) of 100 particles is measured in a plurality of fields of view. The arithmetic average value obtained by the following formula is taken as the average primary particle size. The magnification of such FE-SEM can be in the range of 10,000 to 200,000 times, although it depends on the particle size of the fine particles. Specifically, when the particle diameter is 0.05 μm or more and less than 0.1 μm, it is 100,000 times or more, and when it is 0.1 μm or more and less than 0.3 μm, it is 50,000 times or more, 0.3 μm or more and 0 When it is less than 5 μm, it is 30,000 times or more, and when it is 0.5 μm or more and 1.0 μm or less, it is 10,000 times or more. When the fine particles are not perfectly circular on the image (for example, when they are elliptical), the longest diameter is measured as the particle diameter. Further, when an aggregate in which the fine particles are irregularly gathered is formed, the diameter of the minimum unit fine particles forming the aggregate is measured as the particle diameter. However, when the aggregate is a fusion of a plurality of fine particles and the boundary between the fine particles is not clear, the maximum diameter of the fusion product is measured as the particle size.

（式中、Ｒ_ｉは微粒子個々の粒子径を表わし、Ｄ_ｐは平均１次粒子径を表わす。ｎは測定数を表わし、本実施形態では１００である。）

(In the formula, R _i represents the particle size of each fine particle, D _p represents the average primary particle size, n represents the number of measurements, and is 100 in this embodiment.)

  The sphericity of the PPS fine particles (dispersant-adsorbed PPS fine particles) of the embodiment of the present invention is determined by the sphericity of the raw material PPS fine particles used. Even if the cationic polymer dispersant or the anionic surfactant is adsorbed on the surface of the raw material PPS fine particles, the sphericity measured by the measurement method described later is not substantially affected. The degree is the same as the sphericity of the raw material PPS fine particles. The sphericity of the PPS fine particles and raw material PPS fine particles of the embodiment of the present invention is preferably 80 or more, more preferably 85 or more, particularly preferably 90 or more, and most preferably 98 or more. When the sphericity is low, the fine particles tend to be bulky, and such fine particles are not preferable because the handleability deteriorates. The upper limit of sphericity is 100.

  The sphericity of the PPS fine particles and the raw material PPS fine particles in the embodiment of the present invention is the arithmetic mean value of the sphericity of 30 randomly selected fine particles in an image observed with a scanning electron microscope (FE-SEM). And can be calculated according to the following formula. The sphericity of each fine particle is the ratio of the long diameter (maximum diameter) of each fine particle to the short diameter perpendicular to the long diameter at the center of the long diameter, and can be calculated according to the following formula. The major axis and minor axis of each fine particle were measured at the magnification and field of view described above for measuring the particle diameter in order to obtain the average primary particle diameter.

（式中、Ｓ_ｍは平均真球度（％）を表わし、Ｓ_ｉは微粒子個々の真球度を表わし、ａ_ｉは微粒子個々の短径を表わし、ｂ_ｉは微粒子個々の長径を表わす。ｎは測定数を表わし、本実施形態では３０である。）

(Wherein S _m represents the average sphericity (%), S _i represents the sphericity of each fine particle, a _i represents the short diameter of each fine particle, and b _i represents the long diameter of each fine particle. n represents the number of measurements, and is 30 in this embodiment.)

  The raw material PPS fine particles used in the embodiment of the present invention have a characteristic of having a negative surface potential in the liquid. The surface potential of the raw material PPS fine particles here is the zeta potential of the raw material PPS fine particles in the liquid, and the value can be measured with a zeta potential meter.

  Specifically, a measuring solution having 0.1 parts by mass of fine particles per 100 parts by mass of solvent and an ion concentration of 1 mmol / L was collected in a cell of a zeta electrometer, measured three times at a setting of 25 ° C., and an arithmetic average value thereof Can be the surface potential of the raw material PPS fine particles in the measurement liquid.

  As the raw material PPS fine particles used in the embodiment of the present invention, those having a zeta potential of −5 to −100 m∨ under an environment of pH 7 ± 1 under the above measurement conditions can be used. The lower limit of the value of the zeta potential is preferably −80 m∨ or more and particularly preferably −75 m∨. Further, the upper limit of the value of the zeta potential is preferably -10 m∨ or less, more preferably -15 m 、 or less, and particularly preferably -20 m∨ or less. If the zeta potential is within this range, the electrostatic interaction acting between the raw material PPS fine particles and the cationic polymer dispersant can be secured, and the detachment of the cationic polymer dispersant from the raw material PPS fine particles can be suppressed. It is preferable because an appropriate amount of the cationic polymer dispersant can be adsorbed on the raw material PPS fine particles.

  When the pH responsiveness of the raw material PPS fine particles is measured, the raw material PPS fine particles have an isoelectric point near pH 3 and have a negative zeta potential in the region of pH> 3. From this, it is considered that the zeta potential of the raw material PPS fine particles originates from the terminal functional groups of the raw material PPS resin exposed to the surface of the fine particles, particularly from the carboxylic acid terminal and the carboxylic acid metal salt terminal.

  The amount of the surface carboxylic acid group and the surface carboxylic acid metal salt of the raw material PPS fine particles is not limited as long as the raw material PPS fine particles exhibit a zeta potential in the above-mentioned range in the liquid. In order to obtain a zeta potential of −5 mV or more, The lower limit is preferably 0.1 mmol or more per 100 g of raw material PPS fine particles, more preferably 0.5 mmol or more, further preferably 1 mmol or more, particularly preferably 1.25 mmol or more, and particularly preferably 1 .5 mmol or more. Further, the upper limit of the amount of the surface carboxylic acid group and the surface carboxylic acid metal salt of the raw material PPS fine particles is preferably 100 mmol or less per 100 g of the raw material PPS fine particles, more preferably 75 mmol or less, further preferably 50 mmol or less, The amount is particularly preferably 30 mmol or less, and particularly preferably 20 mmol or less.

  The amount of the surface carboxylic acid group and the surface carboxylic acid metal salt of the raw material PPS fine particles can be experimentally determined by neutralizing and titrating the raw material PPS fine particles treated with hydrochloric acid with a 0.01 mol / L aqueous sodium hydroxide solution. .

<PPS fine particles adsorbed with cationic polymer dispersant; PPS-C fine particles>
With respect to the raw material PPS fine particles, the PPS-C fine particles which are the PPS fine particles according to the embodiment of the present invention are obtained by adsorbing the cationic polymer dispersant on the fine particle surfaces.

  In the embodiment of the present invention, a cationic polymer dispersant is used as the dispersant to be adsorbed on the surface of the raw material PPS fine particles.

  In particular, in the embodiment of the present invention, the polymer dispersant is a substance having a structure having both a hydrophilic group and a lipophilic group in the molecule, and has a repeating unit structure in the molecule. A substance having a hydrophilic group and / or a lipophilic group acting as an adsorbing group in a unit structure, and a substance having a structure having an adsorbing group periodically in a molecule.

  The cationic polymer dispersant in the embodiment of the present invention is a polymer dispersant having at least one hydrophilic group that acts as an adsorbing group in the repeating unit structure in the molecule, and the hydrophilic group is in the liquid. It is a polymer dispersing agent that exhibits cationic properties when dissociated at.

  The polymer dispersant is used for stabilizing the dispersion of fine particles in the medium, and has a function of improving the affinity and wettability with the medium on the surface of the fine particles. It is particularly suitable for stabilizing the dispersion of submicron-sized fine particles. The high steric barrier created by the polymer dispersant prevents the fine particles from approaching each other, and the fine particles aggregate due to van der Waals forces acting between the fine particles. And the dispersibility of the fine particles can be improved. In the embodiment of the present invention, PPS fine particles having excellent dispersibility in a medium can be obtained by adsorbing a cationic polymer dispersant to raw material PPS fine particles.

  In the embodiment of the present invention, adsorption refers to a phenomenon in which one substance is selectively immobilized on the surface of the other substance by the interaction between the substances. The PPS fine particles in which the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles are PPS fine particles in which the cationic polymer dispersant is immobilized on the surface of the raw material PPS fine particles by the interaction between substances.

  As a result of the study by the present inventors, it was found that the raw material PPS fine particles have a negative surface potential in the liquid as described above. Then, by using a cationic polymer dispersant that is positively charged by being dissociated in the liquid, it was found that the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles by electrostatic interaction. It came to the PPS microparticles | fine-particles of embodiment of invention.

  Specifically, the cationic polymer dispersant has a cationic hydrophilic group in the repeating unit structure in the molecule (hereinafter sometimes referred to as a cationic adsorption group) that is positively charged in the liquid. However, it is also considered that the negatively charged raw material PPS fine particles in the liquid show an electrostatic interaction, and the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles through the cationic adsorption group. When the zeta potential of the PPS fine particles after adsorbing the cationic polymer dispersant is measured, the zeta potential of such PPS fine particles changes in the positive direction, and the raw material PPS fine particles and the cationic polymer dispersant are It can be said that it was adsorbed by electrostatic interaction.

  As a phenomenon of adsorption of the dispersant onto the fine particle surface, there is physical adsorption on the interface by van der Waals force in addition to the electrostatic interaction. However, physical adsorption due to van der Waals force is weak, and when the fine particles adsorbed by the van der Waals force are moved from one medium to another medium, the desorption of the dispersant proceeds due to the concentration change, and the dispersion of the fine particles Stability is reduced. In addition, contamination may occur due to the dissociated dispersant, which may adversely affect products made of the resin composition produced using such fine particles.

  On the other hand, since the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles by electrostatic interaction, the cationic polymer dispersant is firmly bonded to the surface of the raw material PPS fine particles and once adsorbed the cationic polymer dispersant. The polymer dispersant is not easily detached. Therefore, the PPS microparticles according to the embodiment of the present invention are controlled by controlling the adsorption amount of the cationic polymer dispersant as described later, so that the cationic polymer dispersant can be moved even if the PPS microparticles are moved from one medium to another medium. Is difficult to desorb and exhibits high dispersibility due to the dispersing effect of the cationic polymer dispersant in a wide variety of media. In addition, since the cationic polymer dispersant is unlikely to desorb, contamination caused by the dispersant that has become free in the medium can be suppressed.

  The cationic polymer dispersant used in the embodiment of the present invention is not particularly limited, and a polymer dispersant having a primary to tertiary amino group as a cationic group can be used. . Specific examples include polyalkylene polyamine, polyallylamine, polyaniline, poly (4-vinylpyridine), poly (2,6 ditertiary butylpyridine), poly (9-vinylcarbazole), and chitosan. Among these, polyalkylene polyamines are preferable, and examples of the polyalkylene polyamines include polyethylene imine and polypropylene imine. Polyethyleneimine is most preferred because of its highest cation density. Further, the cationic polymer dispersant may be used alone or in combination of two or more.

  In addition, the molecular weight of the cationic polymer dispersant is unclear because it depends on the average primary particle diameter of the raw material PPS fine particles, but the weight average molecular weight Mw is in the range of 500 to 1,000,000. Is preferred. The lower limit of the molecular weight is preferably 1,000 or more, more preferably 2,000 or more, further preferably 3,000 or more, particularly preferably 4,000 or more, and particularly preferably 5,000 or more. The upper limit of the molecular weight is preferably 500,000 or less, more preferably 100,000 or less, further preferably 50,000 or less, particularly preferably 25,000 or less, and particularly preferably 20,000 or less.

  The weight average molecular weight Mw here refers to a weight average molecular weight measured by gel permeation chromatography (GPC) using water as a solvent and converted using polyethylene glycol as a standard sample. As a solvent, dimethylformamide is used when water cannot be used, tetrahydrofuran is used when water cannot be measured, and hexafluoroisopropanol is used when water cannot be measured.

  The PPS fine particles of the embodiment of the present invention are PPS fine particles in which 0.1 to 30 parts by mass of a cationic polymer dispersant is adsorbed on the surface of the fine particles per 100 parts by mass of the raw material PPS fine particles. The lower limit of the adsorption amount is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 1.5 parts by mass or more, and particularly preferably 2 parts by mass or more. Remarkably preferably 2.5 parts by mass or more. The upper limit of the adsorption amount is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, and particularly preferably 12.5 parts by mass or less. Remarkably preferably it is 10 parts by mass or less.

  When the adsorption amount of the cationic polymer dispersant is less than 0.1 parts by mass per 100 parts by mass of the raw material PPS fine particles, the amount of the cationic polymer dispersant adsorbed on the surface of the fine particles is small, and the medium by the cationic polymer dispersant Therefore, the redispersibility in a solvent is lowered. In addition, when the adsorption amount is less than 0.1 parts by mass, the number of raw material PPS fine particles increases with respect to the number of molecules of the cationic polymer dispersant, and thus the molecules of the cationic polymer dispersant cross-link a plurality of fine particles. However, adsorbing cross-linking aggregation tends to occur.

  On the other hand, the range in which the adsorbed amount of the cationic polymer dispersant exceeds 30 parts by mass per 100 parts by mass of the raw material PPS fine particles is a range that substantially exceeds the saturated adsorbed amount of the cationic polymer dispersant. There is an excess amount of the cationic polymer dispersant that was not directly adsorbed on the surface of the polymer. These surplus amounts of the cationic polymer dispersant are not adsorbed on the surface of the raw material PPS fine particles, but are converted into the raw material PPS fine particles in a state where molecular chains are entangled with other cationic polymer dispersants adsorbed on the raw material PPS fine particles. (The cationic polymer dispersant in such a state is referred to as “excess cationic polymer dispersant”). The excess cationic polymer dispersant is easily detached, and the PPS-C fine particles containing the excess cationic polymer dispersant are easily detached when dispersed in a solvent. Therefore, if the adsorbed amount of the cationic polymer dispersant exceeds 30 parts by mass per 100 parts by mass of the raw material PPS fine particles, it causes contamination and may adversely affect a product produced using such PPS fine particles. This is not preferable.

  The adsorption amount of the cationic polymer dispersant adsorbed on the surface of the fine particles can be determined by measurement using a differential thermal and thermogravimetric simultaneous measurement device (TG-DTA). Specifically, the thermal decomposition behavior of the bulk cationic polymer dispersant when the temperature is increased from 20 ° C. to 500 ° C. in a nitrogen atmosphere at a rate of temperature increase of 10 ° C./min (thermal decomposition temperature and at that time) Weight loss) (TG-a) and thermal decomposition behavior (TG-b) of raw material PPS fine particles dried by vacuum drying. Subsequently, the PPS-C fine particles adsorbed with the cationic polymer dispersant were completely dried and then subjected to TG-DTA, and the temperature was raised from 20 ° C. to 500 ° C. in a nitrogen atmosphere at a rate of 10 ° C./min. The thermal decomposition behavior is measured (TG-c). By analyzing the thermal decomposition behavior of TG-c based on the results of TG-a and b, by calculating the weight loss amount derived from the cationic polymer dispersant among the weight loss amounts obtained by TG-c, The adsorption amount of the cationic polymer dispersant per 100 parts by mass of the raw material PPS fine particles can be determined.

  The optimum adsorption amount of the cationic polymer dispersant is not unconditionally determined because it depends on the type of the cationic polymer dispersant and the primary particle size of the raw material PPS fine particles, but ideally the cationic polymer dispersant. Of saturated adsorption.

  The saturated adsorption amount of the cationic polymer dispersant is the adsorption amount when the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles to form a monomolecular coating layer, and is created by TG-DTA measurement. It can be obtained from the isotherm. FIG. 1 is an explanatory diagram showing an example of an adsorption isotherm related to the adsorption amount of the cationic polymer dispersant. In FIG. 1, the horizontal axis represents the addition amount of the cationic polymer dispersant per unit mass of the raw material PPS fine particles, and the vertical axis represents the adsorption amount of the cationic polymer dispersant per unit mass of the raw material PPS fine particles. Represent.

  If the adsorption / desorption behavior of the cationic polymer dispersant on the surface of the raw material PPS fine particles occurs according to the single layer adsorption model, the saturated adsorption amount of the cationic polymer dispersant is determined by the concentration of the cationic polymer dispersant (addition) When the adsorption / desorption is performed by changing the amount), the adsorption amount is the amount when the adsorption amount does not increase even if the concentration is increased. The adsorption isotherm pattern assuming that the adsorption / desorption behavior of the cationic polymer dispersant on the surface of the raw material PPS fine particles follows a single-layer adsorption model is shown by a solid line in FIG. In FIG. 1A and FIG. 1B described later, the saturated adsorption amount of the cationic polymer dispersant is shown as As.

  However, actually, when the concentration of the cationic polymer dispersant with respect to the raw material PPS fine particles is high and there is a cationic polymer dispersant of a saturated adsorption amount or more, after the cationic polymer dispersant exhibits saturated adsorption, An excessive amount of the cationic polymer dispersant becomes the “excess cationic polymer dispersant” and is held on the surface of the raw material PPS fine particles. Therefore, when there is a cationic polymer dispersant greater than the saturated adsorption amount, the adsorption / desorption behavior of the cationic polymer dispersant on the surface of the raw material PPS fine particles shows the adsorption / desorption behavior represented by the multilayer adsorption model. it is conceivable that. Specifically, the adsorption amount of the cationic polymer dispersant increases beyond the saturated adsorption amount as the concentration of the cationic polymer dispersant increases. The adsorption isotherm pattern when the adsorption / desorption behavior of the cationic polymer dispersant on the surface of the raw material PPS fine particles follows the multilayer adsorption model is shown by a solid line in FIG. In FIG. 1 (B), a state in which the adsorption amount increases beyond the saturated adsorption amount is indicated by a dashed arrow.

  When the PPS-C fine particles contain an excess cationic polymer dispersant, the value of the adsorption amount calculated by TG-DTA measurement is the amount of the cationic polymer dispersant adsorbed on the raw material PPS fine particles and the molecular chain. The total amount of the excess cationic polymer dispersant generated by the entanglement is obtained.

  The presence or absence of excess cationic polymer dispersant is based on the shape of the adsorption isotherm, and specifically depends on whether the adsorption isotherm shows the pattern of FIG. 1 (A) or FIG. 1 (B). Judgment can be made. When the PPS-C fine particles contain an excess cationic polymer dispersant, the pattern shown in FIG. 1 (B) is shown. If an adsorption isotherm is created again after the washing step described later, the adsorption isotherm of the washed particles is obtained. The line follows the single layer adsorption model as shown in FIG. That is, the shape of the adsorption isotherm is a shape in which the adsorption amount does not change even when the concentration of the cationic polymer dispersant is increased above a specific value corresponding to the saturated adsorption amount. Therefore, based on the adsorption isotherm after washing, the saturated adsorption amount can be obtained as the specific value. If the excess cationic polymer dispersant cannot be sufficiently removed by one washing, the adsorption amount of the cationic polymer dispersant can be brought close to the saturated adsorption amount by repeating the washing. In FIG. 1A, a state in which a pattern according to a single layer adsorption model is approached by increasing the number of times of cleaning the fine particles having the adsorption pattern shown in FIG.

  By measuring the adsorption amount of the cationic polymer dispersant by the above operation, the saturated adsorption amount of the cationic polymer dispersant can be determined, and at the same time, the presence or absence of the excess cationic polymer dispersant can be determined.

  Moreover, the PPS microparticles | fine-particles of embodiment of this invention have the characteristics that the content rate of a volatile component is less than 50 mass% in a dispersing agent adsorption | suction PPS microparticles | fine-particles.

  The content rate of a volatile component can be measured by TG-DTA. Specifically, the content of volatile components is the weight loss rate when 10 mg of PPS fine particles are precisely weighed and heated from 20 ° C. to 200 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere. Can be sought.

  The content of volatile components is preferably less than 30% by weight, more preferably less than 15% by weight, even more preferably less than 10% by weight, particularly preferably less than 7.5% by weight, particularly preferably less than 5% by weight, The lower limit is ideally 0% by mass.

  Volatile components whose content is required by the above measurement method are mainly residual volatile solvents contained in the PPS-C fine particles. By setting the content of the volatile component to less than 50% by mass, the PPS fine particles according to the embodiment of the present invention are introduced into a dispersion medium and redispersed to form a dispersion. It can be reduced that the medium and the residual solvent are separated without being mixed, and the PPS fine particles of the embodiment of the present invention cause poor dispersion.

  Since the PPS microparticles of the embodiment of the present invention have a cationic polymer dispersant that is firmly bonded to the surface of the microparticles, they can be easily redispersed in a medium even in a low liquid content state. is there. That is, for example, when redispersed in a solvent, since it can be redispersed in a wide variety of solvents without the operation of solvent replacement, which is essential in the prior art, the PPS microparticles of the embodiments of the present invention are economical. Both environmentally and environmentally.

<PPS fine particles adsorbed with an anionic surfactant; PPS-CA fine particles>
The PPS fine particles according to the embodiment of the present invention can be PPS-C-A fine particles in which an anionic surfactant is further adsorbed on the surface of the PPS-C fine particles in addition to the cationic polymer dispersant.

  By further adsorbing the anionic surfactant to the PPS-C fine particles to which the cationic polymer dispersant is adsorbed, the PPS fine particles of the embodiment of the present invention can be dispersed in a wider range of media. The reason is as follows. In other words, since the cationic polymer dispersant generally has a large number of ultrafine devices, even if the cationic polymer dispersant is used, the effect of improving the dispersibility in a non-aqueous medium may not be sufficiently obtained. In such a case, the polar group of the cationic polymer dispersant can be neutralized by using an anionic surfactant in addition to the cationic polymer dispersant. Further, by further using an anionic surfactant, a functional group having high affinity with a non-aqueous medium can be introduced on the surface of the PPS fine particles. As a result, the effect of improving the dispersibility of the PPS fine particles can be enhanced even in a non-aqueous medium. It should be noted that an anionic surfactant alone cannot be adsorbed on PPS fine particles by electrostatic interaction. Therefore, the above effect is an effect obtained by adsorbing the cationic polymer dispersant to the PPS fine particles and further adsorbing the anionic surfactant.

  The term “surfactant” as used herein refers to a substance having a structure having both a hydrophilic group and a lipophilic group in the molecule, or one having no repeating unit structure in the molecule, or having a repeating structure in the molecule. , Refers to those having a hydrophilic group and / or a lipophilic group substantially acting as an adsorbing group outside the repeating unit structure.

  An anionic surfactant is a surfactant having a hydrophilic group that substantially acts as an adsorbing group, and the hydrophilic group exhibits an anionic property when dissociated in a liquid.

  Anionic surfactants are generally widely used surfactants, and various types of structures are commercially available from various companies. As described above, since anionic surfactants having desired characteristics can be easily selected from many types, the structure is selected according to the dispersion medium and adsorbed on the PPS-C fine particles. Thus, the affinity of the PPS fine particles to the dispersion medium and the wettability are improved, and PPS fine particles that can be dispersed in a wider range of solvents can be obtained.

  The anionic surfactant is adsorbed and strongly bonded to the cationic polymer dispersant on the surface of the PPS-C fine particles by electrostatic interaction. Specifically, among the cationic adsorption groups of the cationic polymer dispersant adsorbed on the surface of the raw material PPS fine particles, free cationic adsorption groups that do not interact with the PPS fine particles, and the hydrophilic property of the anionic surfactant Hydrophilic groups that dissociate in liquid and show anionic properties (hereinafter sometimes referred to as anionic adsorptive groups) are positively and negatively charged in the liquid, and electrostatic interaction It is thought that it adsorbs at

  Such a phenomenon should be confirmed by comparing the zeta potential of the PPS-C fine particles before adsorbing the anionic surfactant and the PPS-C-A fine particles after adsorbing the anionic surfactant. Can do.

  Specifically, when 100 parts by mass of solvent, 0.1 parts by mass of particles and a measurement solution having an ion concentration of 1 mmol / L are collected in a zeta electrometer cell and measured at a setting of 25 ° C., PPS-C fine particles are While having a positive zeta potential, the zeta potential of the PPS-CA fine particles is near zero, so that an electrostatic interaction is acting between the cationic adsorption group and the anionic adsorption group. Can be guessed.

  Since an anionic surfactant is adsorbed by electrostatic interaction, even if the PPS-CA fine particles are moved from one medium to another medium, the once adsorbed anionic surfactant is easily desorbed. The PPS fine particles exhibit high redispersibility in a wide variety of media due to the high wettability effect of the anionic surfactant. Further, since the desorption of the anionic surfactant from the PPS-CA fine particles hardly occurs, contamination caused by the surfactant that has become free in the medium can be suppressed.

  The anionic surfactant that can be used in the embodiment of the present invention is not particularly limited, and examples thereof include those having a carboxylic acid, sulfonic acid or phosphoric acid structure as a hydrophilic group, or metal salts thereof. Specific examples include fatty acids, alkylbenzene sulfonic acids, alkyl sulfate salts, alkyl sulfonic acids, alkyl ether sulfate salts, polyoxyethylene aryl ether sulfate salts, polyoxyalkylene alkyl ether sulfate salts, monoalkyl phosphorus Examples include acid ester salts, polyoxyalkylene alkyl ether phosphoric acids, fatty acid ester sulfonic acids, and metal salts thereof.

  The structure of the anionic surfactant is preferably selected according to the target dispersion medium. More specifically, a surfactant selected from a carboxylic acid type and a phosphoric acid type is preferable because the interaction with the cationic polymer dispersant is strong. Moreover, since the dispersion medium which can disperse | distribute the PPS microparticles | fine-particles of embodiment of this invention can be made wider, it is more preferable that it is surfactant selected from a fatty acid and polyoxyalkylene alkyl ether phosphoric acid. These anionic surfactants may be used alone or in combination of two or more.

  The adsorption amount of the anionic surfactant is preferably 0.1 to 50 parts by mass per 100 parts by mass of the raw material PPS fine particles. The lower limit of the adsorption amount is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 2.5 parts by mass or more, particularly preferably 3 parts by mass or more, and extremely preferably 3.5 parts by mass or more. Further, the upper limit of the adsorption amount is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 25 parts by mass or less, particularly preferably 20 parts by mass or less, and extremely preferably. Is 15 parts by mass or less.

  When the adsorption amount of the anionic surfactant is too small, for example, when it is less than 0.1 parts by mass per 100 parts by mass of the raw material PPS fine particles, the anionic surfactant that is adsorbed by the interaction with the cationic polymer dispersant Since the amount of the agent is small, the effect of improving the affinity with the dispersion medium by the anionic surfactant is not exhibited, and the effect of improving the redispersibility of the fine particles is not sufficiently exhibited.

  On the other hand, when the adsorption amount of the anionic surfactant is too large, for example, when it exceeds 50 parts by mass per 100 parts by mass of the raw material PPS fine particles, the saturated adsorption amount of the anionic surfactant is substantially exceeded, There is an excess amount of anionic surfactant that does not exhibit an electrostatic interaction with the cationic polymer dispersant. These excessive amounts of anionic surfactants themselves are not adsorbed with the cationic polymer dispersant, but become fine particles in a state where molecular chains are entangled with other anionic surfactants adsorbed on the cationic polymer dispersant. Retained (the anionic surfactant in such a state is referred to as “excess anionic surfactant”). Excess anionic surfactant is easily desorbed, and if PPS fine particles containing an excess anionic surfactant are dispersed in a solvent, they are easily desorbed and cause contamination, which is not preferable.

  The adsorption amount of the anionic surfactant can be determined by measurement with a differential thermal and thermogravimetric measurement apparatus (TG-DTA), similarly to the adsorption amount of the cationic polymer dispersant. Specifically, the thermal decomposition behavior (TG) of the bulk cationic polymer dispersant described above when the temperature is raised from 20 ° C. to 500 ° C. under conditions of a temperature rising rate of 10 ° C./min and a nitrogen atmosphere. -A), the thermal decomposition behavior of the raw material PPS fine particles dried by vacuum drying (TG-b), and the thermal decomposition behavior of the PPS-C fine particles dried absolutely by vacuum drying (TG-c) In addition, the thermal decomposition behavior (TG-d) of the bulk anionic surfactant and the thermal decomposition behavior (TG-e) of the PPS-CA fine particles are measured. Then, the thermal decomposition behavior of TG-e is analyzed based on the results of TG-d and measurement TG-a to c, and the weight loss derived from the anionic surfactant among the weight loss obtained by TG-e. By calculating the amount, the adsorption amount of the anionic surfactant per 100 parts by mass of the raw material PPS fine particles can be obtained.

  The optimum adsorption amount of the anionic surfactant depends on the kind of the anionic surfactant, the kind of the cationic polymer dispersant, and the primary particle size of the raw material PPS fine particles. This is the saturated adsorption amount of the anionic surfactant.

  The saturated adsorption amount of the anionic surfactant is the adsorption amount when the anionic surfactant is adsorbed on the PPS-C fine particles to form a monomolecular coating layer, and like the cationic polymer dispersant, It can obtain | require from the adsorption isotherm created by TG-DTA measurement.

  The adsorption / desorption behavior of an anionic surfactant is considered to follow a single-layer adsorption model until the adsorption amount of the anionic surfactant reaches the saturated adsorption amount, and there exists an anionic surfactant that exceeds the saturated adsorption amount. The case is considered to follow a multilayer adsorption model.

  When the adsorption / desorption behavior of the anionic surfactant occurs according to the single-layer adsorption model only, the saturated adsorption amount of the anionic surfactant is determined when the adsorption / desorption is performed by changing the concentration of the anionic surfactant. Even if the concentration is increased, the amount of adsorption is the amount when the amount of adsorption no longer increases. In such a case, the adsorption behavior with the anionic surfactant shows the same pattern as in FIG.

  However, in actuality, when an anionic surfactant having a saturation adsorption amount or more is present, the adsorption / desorption behavior of the anionic surfactant follows a multilayer adsorption model similar to that shown in FIG. When the PPS-C-A fine particles contain an excess anionic surfactant, the excess anionic surfactant is used in the washing step described later in the same manner as the method for calculating the saturated adsorption amount of the cationic polymer dispersant described above. After the removal of, the adsorption isotherm of the anionic surfactant is created again to calculate the saturated adsorption amount of the anionic surfactant.

  Similarly to the PPS-C fine particles, the PPS-CA fine particles of the embodiment of the present invention have a feature that the content of volatile components is less than 50% by mass in the dispersant-adsorbed PPS fine particles.

  The content of volatile components in the PPS-C-A fine particles can be obtained in the same manner as the content of volatile components in the PPS-C fine particles. The content of volatile components in the PPS-C-A fine particles is preferably less than 30% by mass, more preferably less than 15% by mass, further preferably less than 10% by mass, particularly preferably less than 7.5% by mass, and most preferably The lower limit is ideally 0% by mass.

  The volatile component is a residual volatile solvent mainly contained in the PPS-CA fine particles. By setting the content of the volatile component to less than 50% by mass, the PPS fine particles according to the embodiment of the present invention are introduced into a dispersion medium and redispersed to form a dispersion. It can be reduced that the medium and the residual solvent are separated without being mixed, and the PPS fine particles of the embodiment of the present invention cause poor dispersion.

<Method for producing raw material PPS fine particles>
The raw material PPS fine particles used in the embodiment of the present invention may be PPS fine particles obtained by any production method, for example, a quench method in which the raw material PPS resin is gradually cooled after polymerization to form granules; Flash method of scattering and precipitating; Mechanical pulverization method of refining raw material PPS resin using ball mill, bead mill, jet mill, mortar, etc .; forced melt kneading method; spray drying method; or solution of raw material PPS resin dissolved Examples include a precipitation method by cooling. Among these, the following flash cooling method in which the raw material PPS resin solution in a heated and pressurized state is rapidly cooled by jetting it into a poor solvent to precipitate the raw material PPS fine particles is most preferable.

  The method of rapidly cooling the raw material PPS resin solution in a heated / pressurized state by jetting and precipitating the raw material PPS fine particles includes a dissolution step and a precipitation step. The dissolution step is a step of heating the raw material PPS resin in an organic solvent to obtain a raw material PPS resin solution. The precipitation step is a step of precipitating raw material PPS resin fine particles by flash cooling the solution.

[Dissolution process]
In the dissolving step, the raw material PPS resin is heated and dissolved in an organic solvent. Although the dissolution method is not particularly limited, the raw material PPS resin and the organic solvent are put in a predetermined container and heated while stirring to dissolve the raw material PPS resin in the organic solvent.

  There is no restriction | limiting in the form of raw material PPS resin which can be used at a melt | dissolution process, Any PPS, such as a powder, a granule, a pellet, a fiber, a film, a molded article, can be used. Use of powders, granules, or pellets is preferable because operability can be improved and dissolution time can be shortened. These PPS may be used in a mixture of plural forms or may be used alone, but the use of powder is particularly preferred. Moreover, as raw material PPS resin to be used, the thing which does not contain an inorganic ion is preferable.

  The organic solvent used for dissolving the raw material PPS resin in the dissolving step is not particularly limited as long as the raw material PPS resin is dissolved. Specific examples include organic amide solvents such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylcaprolactam. These solvents may be used alone or in combination. From the viewpoint of the solubility of the raw material PPS resin, N-methyl-2-pyrrolidone is preferred.

  The raw material PPS resin is dissolved in the organic solvent to prepare a raw material PPS resin solution, but the concentration of the raw material PPS resin in the organic solvent is not limited. Even if the raw material PPS resin does not completely dissolve in the organic solvent at a predetermined temperature, the undissolved raw material PPS resin can be easily removed by filtration or centrifugation. However, in terms of simplification of the manufacturing method and cost, it is preferable that undissolved PPS does not exist. For this purpose, the concentration of the raw material PPS resin is 0.5 to 10 parts by mass with respect to 100 parts by mass of the organic solvent. It is preferable to be in the range.

  The atmosphere during the melting step is preferably an inert gas atmosphere. As the inert gas, a gas selected from nitrogen, helium, argon, and carbon dioxide is preferable, and nitrogen or argon is more preferable.

  The heating temperature when dissolving the raw material PPS resin in the organic solvent cannot be uniquely determined because the preferred temperature varies depending on the type of raw material PPS resin used and the type of organic solvent, but preferably 180 ° C. or higher, More preferably, it is 210 degreeC or more, More preferably, it is 230 degreeC or more, Especially preferably, it is 240 degreeC or more, Most preferably, it is 250 degreeC or more. The upper limit is not particularly limited, but is usually 400 ° C. or lower because the raw material PPS resin is decomposed when the temperature is too high.

  The said temperature may exceed the boiling point of the organic solvent to be used. Therefore, in order to efficiently dissolve the raw material PPS resin at a temperature equal to or higher than the boiling point of the solvent, it is desirable to perform the dissolution process using a pressure vessel such as an autoclave.

  The pressure in the dissolution step may be a pressure at which the organic solvent does not boil at the temperature at which the raw material PPS resin is dissolved, and may be higher than the saturated vapor pressure of the organic solvent at the dissolution temperature. From the viewpoint of industrial feasibility, the upper limit of the pressure is preferably 100 atm (10 MPa) or less, more preferably 50 atm (5.0 MPa) or less, further preferably 10 atm (1 MPa) or less, particularly preferably 5 atm ( 0.5 MPa) or less.

[Precipitation process]
In the precipitation step, the raw material PPS resin solution obtained in the dissolution step is ejected into a poor solvent and rapidly cooled to precipitate, thereby obtaining raw material PPS fine particles. In particular, the above-mentioned dissolved solution in a heated / pressurized state is ejected through a nozzle to a poor solvent bath under a temperature and pressure lower than those in the dissolving step, and transferred, and the cooling effect due to the pressure difference and the cooling effect due to latent heat The method of rapid cooling is called flash cooling.

The method of flash cooling is not particularly limited. For example, when the raw material PPS resin is dissolved in an organic solvent under heating and pressurizing conditions using an autoclave in the reaction tank in the dissolution step, the raw material PPS resin solution Can be carried out by putting the outlet of the connecting pipe through a connecting pipe from the autoclave into a poor solvent in a poor solvent tank at a lower temperature and lower pressure than the autoclave. In addition, what is necessary is just to inject into a poor solvent, after pressurizing the solution of the raw material PPS resin obtained at the melt | dissolution process, when a melt | dissolution process is performed without accompanying a pressurization.

  By performing the flash cooling, fine particles of the raw material PPS resin are precipitated from the solution of the raw material PPS resin, and a suspension of the raw material PPS fine particles is obtained. At this time, it is preferable that at least one of the temperature difference and the pressure difference between the reaction tank and the poor solvent tank is larger because flash cooling is performed more rapidly and the obtained raw material PPS fine particles become finer.

  In order to make the primary particle diameter of the raw material PPS fine particles to be a submicron size, it is desirable to perform flash cooling more rapidly. For this purpose, the above-mentioned state in which the reaction vessel (preferably an autoclave) is heated and pressurized is used. It is preferable that the solution is jetted through a connecting pipe or the like into a poor solvent tank under atmospheric pressure and flash-cooled.

  In addition, it is preferable to cool the poor solvent tank with a refrigerant or ice water. It is preferable to cool the poor solvent in the poor solvent tank in advance, because the transferred solution can be rapidly cooled below the boiling point of the organic solvent, and more rapidly flash-cooled to obtain fine raw material PPS fine particles.

  Further, it is considered that the raw material PPS fine particles having higher sphericity can be obtained by flash cooling more rapidly, thereby suppressing the coalescence of the raw material PPS fine particles in the precipitation process.

  In order to perform flash cooling more rapidly, it is desirable that the temperature of the antisolvent tank is low, but it must be higher than the temperature at which the antisolvent solidifies. Although the preferable temperature of a poor solvent tank changes with kinds of poor solvent and cannot be determined uniquely, it is preferable that it is 50 degrees C or less.

  Although there is no restriction | limiting in particular as a poor solvent used by the said flash cooling, From a viewpoint of performing flash cooling efficiently, it is preferable that it is a solvent which mixes uniformly with the said organic solvent and does not melt | dissolve raw material PPS resin. Here, uniformly mixing means that when two or more solvents are mixed by the same mass part, an interface does not appear even if the mixture is allowed to stand for one day and shows a uniform state. The solvent that does not dissolve the raw material PPS resin refers to a solvent having a solubility of the raw material PPS resin in the solvent of 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less. It is.

  Specific examples of the poor solvent vary depending on the kind of raw material PPS resin and the kind of the organic solvent, but pentane, hexane, heptane, octane, nonane, n-decane, n-dodecane, n-tridecane, cyclohexane, Aliphatic hydrocarbon solvents such as cyclopentane; aromatic hydrocarbon solvents such as benzene, toluene and xylene; alcohol solvents such as methanol, ethanol, 1-propanol and 2-propanol; and solvents selected from water Etc. From the viewpoint of obtaining raw material PPS fine particles by efficient flash cooling, a solvent selected from an alcohol solvent and water is preferable, and water is more preferable.

  Although the quantity of a poor solvent is not specifically limited, The range of 10 mass parts-10,000 mass parts can be illustrated with respect to 100 mass parts of solvent of a melt | dissolution process. Although it depends on the efficiency of flash cooling depending on the type of the poor solvent, the upper limit of the amount of the poor solvent is preferably 5,000 parts by mass or less, more preferably 1,000 parts by mass or less, and even more preferably 500 parts by mass or less. is there.

  Subsequently, the suspension of the raw material PPS fine particles obtained by flash cooling is subjected to solid-liquid separation by a generally known method such as filtration, vacuum filtration, pressure filtration, centrifugation, centrifugal filtration, spray drying, etc. Collect fine particles.

  The raw material PPS fine particles obtained by flash cooling often have an average primary particle size of 1 μm or less, and in order to efficiently isolate such fine particles, solid-liquid separation with an ultracentrifuge, It is desirable that the raw material PPS fine particles are once aggregated and then solid-liquid separated by the above-mentioned various filtrations and centrifugal separations.

  Examples of the method for aggregating the raw material PPS fine particles include a natural aggregating method for aggregating with time, an aggregating method by heating, and an aggregating method using an aggregating agent such as salting out.

  The natural agglomeration method is a method of facilitating agglomeration of fine particles by allowing the suspension to stand for 1 day or more to facilitate isolation. The aggregation method by heating is a method of shortening the aggregation time by heating the suspension to 50 ° C. to less than 100 ° C. among the natural aggregation methods. In the salting out, the salt as a flocculant is added in an amount of 0.1 to 1,000 parts by weight, preferably 0.5 to 500 parts by weight, with respect to 100 parts by weight of the raw PPS fine particles. Aggregates can be obtained. Among them, agglomeration by salting out is preferred because of its high agglomeration effect, and a solution in which 0.1 to 20 parts by mass of salt is dissolved in 100 parts by mass of the suspension and the solvent is added directly to the suspension. It is preferable to mix.

  Salts used for salting out include sodium chloride, magnesium chloride, calcium chloride, lithium chloride, potassium chloride, sodium acetate, magnesium acetate, calcium acetate, sodium oxalate, magnesium oxalate, calcium oxalate, sodium citrate, citric acid. Examples include magnesium acid and calcium citrate. As the solvent for dissolving the salt, water is preferable.

  The salt and the solution thereof may be mixed with the suspension, or may be dissolved in advance in a poor solvent in the precipitation step.

  The agglomerated raw material PPS fine particles can be solid-liquid separated by the above filtration and centrifugation, and a wet cake of the raw material PPS fine particles can be obtained. In addition, the wet cake of the raw material PPS fine particles separated by solid-liquid separation can be refined by removing attached or contained impurities by washing with a solvent or the like as necessary.

  About the wet cake of the raw material PPS fine particles obtained as described above, the PPS fine particles of the embodiment of the present invention can be obtained by subsequently subjecting the wet cake to the production method described below.

<Method for producing PPS-C fine particles>
The method for producing the PPS fine particles of the embodiment of the present invention is not particularly limited as long as the PPS fine particles of the embodiment of the present invention can be obtained. For example, the raw material PPS fine particles and the cationic polymer dispersion are dispersed in the solvent (A). And a second step of removing the solvent (A) from the raw material PPS fine particles contacted with the cationic polymer dispersant. The “first step” corresponds to “step 1” described later. The “second step” corresponds to “removal step 1” described later. The solvent (A) corresponds to the first solvent (A) in [Means for Solving the Invention]. Hereinafter, each process will be described in detail.

[Step 1]
The PPS fine particles (PPS-C fine particles), which are PPS fine particles according to an embodiment of the present invention and on which the cationic polymer dispersant is adsorbed, are made cationic in step 1 in the solvent (A). By contacting the polymer dispersant, the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles.

  The PPS-C fine particles of the embodiment of the present invention are PPS fine particles in which a cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles by electrostatic interaction. In order to develop an electrostatic interaction between the cationic polymer dispersant and the raw material PPS fine particles, the cationic polymer dispersant and the raw material PPS fine particles are charged with a solvent (A). In the solvent (A), by bringing the charged raw material PPS fine particles and the cationic polymer dispersant into contact with each other, the surface of the raw material PPS fine particles is brought into contact with the surface of the raw material PPS fine particles by electrostatic interaction. It is considered that PPS fine particles having a molecular dispersant adsorbed are obtained.

  The charge of the cationic polymer dispersant is due to ionization of the cationic adsorption group in the molecule, and the charge of the raw material PPS fine particles is due to the zeta potential of the particles. Accordingly, the solvent (A) used in Step 1 needs to be a solvent in which the cationic adsorption group of the cationic polymer dispersant is ionized and the raw material PPS fine particles exhibit a zeta potential.

  Examples of such a solvent (A) include lower alcohols such as water, methanol, ethanol, n-propyl alcohol, and isopropyl alcohol. Among these, water is preferable because the cationic adsorption group of the cationic polymer dispersant is ionized and the absolute value of the zeta potential of the raw material PPS fine particles is increased.

  At this time, the method for bringing the cationic polymer dispersant and the raw material PPS fine particles into contact with each other in the solvent (A) is not particularly limited as long as the PPS-C fine particles of the embodiment of the present invention are obtained. For example, a method in which the solvent (A), the raw material PPS fine particles, and the cationic polymer dispersant are added to the same container and then allowed to stand; a method in which the solvent (A) is added to the same container and then stirred and mixed; and a solvent (A And a flow path of the mixture of the raw material PPS fine particles and a flow path of the mixture of the solvent (A) and the cationic polymer dispersant; a mixture of the solvent (A) and the raw material PPS fine particles, and the solvent (A) And a mixture of the cationic polymer dispersant and spraying them in a droplet state. Among these, since the apparatus to be used is simple and the efficiency of bringing the raw material PPS fine particles and the cationic polymer dispersant into contact with each other is preferable, the method of stirring and mixing after the addition into the container is preferable.

  In step 1, the raw PPS fine particles and the cationic polymer dispersant are brought into contact with each other in the solvent (A), and the time for promoting the adsorption of the cationic polymer dispersant is 0.01 to 24 hours depending on the contact method. It is preferable that If it is less than 0.01 hour, the adsorption equilibrium is not reached and unadsorbed raw material PPS fine particles may be generated, which is not preferable. On the other hand, if it exceeds 24 hours, the process is prolonged, which is preferable from an industrial viewpoint. Absent.

  The lower limit of the time required for adsorption in step 1 is more preferably 0.25 hours or more, and further preferably 0.5 hours or more. Further, the upper limit of the time taken for adsorption in Step 1 is more preferably 12 hours or less, further preferably 8 hours or less, particularly preferably 5 hours or less, and particularly preferably 3 hours or less.

  It is preferable that the density | concentration of the raw material PPS microparticles | fine-particles in the process 1 is the range of 1-50 mass parts with respect to 100 mass parts of solvent (A). The lower limit of the concentration of the raw material PPS fine particles with respect to 100 parts by mass of the solvent (A) is more preferably 5 parts by mass or more. Further, the upper limit of the concentration of the raw material PPS fine particles is more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

  When the density | concentration of the raw material PPS microparticles | fine-particles in a solvent (A) is low, the working efficiency of the process 1 will become low and it is industrially unpreferable. On the other hand, if the concentration of the raw material PPS fine particles is too high, the raw material PPS fine particles may become lumped without being adapted to the solvent (A), or the viscosity of the system may be increased, and workability may be deteriorated.

  The concentration of the raw material PPS fine particles in the solvent (A) is set in the above range, and the raw material PPS fine particles and the cationic polymer dispersant are brought into contact with each other in the solvent (A), thereby performing Step 1 described in detail below.

  The concentration of the cationic polymer dispersant to be brought into contact with the raw material PPS fine particles in the solvent (A) can be 0.1 to 100 parts by mass with respect to 100 parts by mass of the raw material PPS fine particles.

  In step 1, the lower limit concentration of the cationic polymer dispersant is preferably 0.5 parts by mass or more, more preferably 1.3 parts by mass or more, further preferably 100 parts by mass of the raw material PPS fine particles. Is 2 parts by mass or more, particularly preferably 2.8 parts by mass or more, and particularly preferably 3.5 parts by mass or more. Further, the upper limit concentration is preferably 80 parts by mass or less, more preferably 70 parts by mass or less, further preferably 60 parts by mass or less, particularly preferably 50 parts by mass or less, and extremely preferably. It is 40 parts by mass or less.

  When the concentration of the cationic polymer dispersant in step 1 is less than 0.1 parts by mass, the amount of the cationic polymer dispersant adsorbed on the surface of the raw material PPS fine particles decreases, and the redispersibility in the solvent decreases. Moreover, it is not preferable because crosslinking aggregation by the cationic polymer dispersant is likely to occur.

  The range where the concentration of the cationic polymer dispersant exceeds 100 parts by mass is a range where the amount of the added cationic polymer dispersant clearly exceeds the saturated adsorption amount on the raw material PPS fine particles. Since the excess cationic polymer dispersant exceeding the saturated adsorption amount is not used for adsorption to the fine particles, it is obviously not economically preferable to use an excessive amount of the cationic polymer dispersant.

  The PPS-C fine particles obtained in step 1 are likely to contain an excess cationic polymer dispersant depending on the particle size of the raw material PPS fine particles in addition to the concentration of the cationic polymer dispersant used in step 1. Therefore, after Step 1, it is desirable to perform a step for removing excess cationic polymer dispersant (washing step 1 described later) as necessary, and then a step for removing solvent (A) described later. .

  In addition, in order to simplify the manufacturing method of PPS-C microparticles | fine-particles, about the process 1, the density | concentration of the cationic polymer dispersing agent contacted with raw material PPS microparticles | fine-particles in a solvent (A) is 100 mass parts of raw material PPS microparticles | fine-particles. 0.1 to 30 parts by mass. By setting the concentration of the cationic polymer dispersant in the above range, it is possible to obtain PPS-C fine particles containing almost no excess cationic polymer dispersant. Such a PPS-C fine particle can perform the removal process of a solvent (A) without going through the washing | cleaning process 1 mentioned later.

  As used herein, it means that the excess cationic polymer dispersant is hardly contained, because the adsorption amount of the cationic polymer dispersant of the PPS-C fine particles calculated by TG-DTA measurement is that of the cationic polymer dispersant. It means that it is in a range not exceeding 1.5 times the saturated adsorption amount. That is, it means that the amount of excess cationic polymer dispersant is in a range not exceeding 50 mass% of the saturated adsorption amount.

  The amount of the excess cationic polymer dispersant should be small, preferably 40% by mass or less of the saturated adsorption amount, more preferably 30% by mass or less, further preferably 20% by mass or less, and particularly preferably 10% by mass or less. is there. It is preferable to control the amount of the cationic polymer dispersant used in Step 1 so that the content of the excess cationic polymer dispersant in the PPS-C fine particles obtained in Step 1 is in the above range.

  In order to hardly contain the excess cationic polymer dispersant, the concentration of the cationic polymer dispersant in the solvent (A) is, for example, 0.1 to 30 parts by mass with respect to 100 parts by mass of the raw material PPS fine particles. be able to. The lower limit concentration of the cationic polymer dispersant in the solvent (A) is preferably 0.5 parts by mass or more, more preferably 1.3 parts by mass or more, further preferably 2 parts by mass with respect to 100 parts by mass of the raw material PPS fine particles. In particular, the content is preferably 2.8 parts by mass or more, and particularly preferably 3.5 parts by mass or more. The upper limit concentration is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, particularly preferably 12.5 parts by mass or less, and extremely preferably. Is 10 parts by mass or less.

  When the concentration of the cationic polymer dispersant in step 1 is less than 0.1 parts by mass, as described above, the amount of the cationic polymer dispersant adsorbed on the surface of the raw material PPS fine particles decreases, and re-dispersion in the solvent Low. Moreover, it is not preferable because crosslinking aggregation by the cationic polymer dispersant is likely to occur.

  On the other hand, the range in which the concentration of the cationic polymer dispersant exceeds 30 parts by mass is a range in which the obtained PPS-C fine particles can contain an excess cationic polymer dispersant. That is, the adsorption amount of the cationic polymer dispersant measured by TG-DTA may exceed 1.5 times the saturated adsorption amount. In such a case, the PPS-C fine particles obtained in Step 1 may be used. The necessity for going to the washing | cleaning process 1 will arise.

[Washing process 1]
The PPS-C fine particles obtained in the step 1 can be subjected to a step of removing the excess cationic polymer dispersant (washing step 1) by washing with a washing solvent (A) as necessary.

  The PPS-C fine particles obtained in step 1 are desirably subjected to washing step 1 after solid-liquid separation by a generally known method such as filtration, vacuum filtration, pressure filtration, centrifugation, centrifugal filtration, spray drying and the like.

  In cleaning step 1, 10 to 10,000 parts by mass of the cleaning solvent (A) per 100 parts by mass of the raw material PPS fine particles used in step 1 and the PPS-C fine particles obtained in step 1 are brought into contact with each other for cleaning. Is preferred. Thereby, the excess cationic polymer dispersant is desorbed from the PPS-C fine particles obtained in Step 1, and the excess cationic polymer dispersant is removed.

  When the cleaning solvent (A) used in the cleaning step 1 is less than 10 parts by mass, the cleaning effect is small and inefficient, which is not preferable. When the amount of the cleaning solvent (A) exceeds 10,000 parts by mass, the amount of the solvent used for the cleaning is increased, resulting in an increase in equipment size, which is not preferable from an industrial viewpoint.

  In addition, as a contact method of PPS-C microparticles | fine-particles and a washing | cleaning solvent (A) here, the various contact methods mentioned in the process 1 can be used. Among these, stirring and mixing are preferable from the viewpoint of easy operation and washing efficiency.

  In the washing step 1, it is preferable to mix the PPS-C fine particles and the washing solution (A) until the adhesion / desorption due to the entanglement of the excess cationic polymer dispersant reaches an equilibrium. The cleaning time in the cleaning step 1 cannot be uniquely determined because it varies depending on the type of the cationic polymer dispersant, the type of the cleaning solvent (A), and the contact method of the cleaning solvent (A). 0.01 to 24 hours. The lower limit of the washing time is preferably 0.1 hour or longer, more preferably 0.25 hour or longer. The upper limit of the washing time is preferably 12 hours or less, more preferably 6 hours or less, further preferably 3 hours or less, particularly preferably 1 hour or less, and extremely preferably 0.5 hours or less.

  If the cleaning time is less than 0.01 hours, the cleaning effect is low, and the number of cleanings described later increases, which complicates the work. If the cleaning time exceeds 24 hours, it leads to a prolonged process, which is not preferable from an industrial viewpoint.

  It is desirable to repeat the washing step 1 until the adsorption amount of the cationic polymer dispersant adsorbed on the PPS-C fine particles obtained after washing becomes equal to the saturated adsorption amount.

  Here, the adsorption amount is equal to the saturated adsorption amount, and it is not necessary that the adsorption amount completely coincides with the saturated adsorption amount, and the following range is allowed. Specifically, it indicates that the adsorption amount is in the range of 1.5 times or less of the saturated adsorption amount, preferably 1.4 times or less, more preferably 1.3 times or less, particularly preferably 1 .2 times or less, particularly preferably within 1.1 times or less. Further, it means that the adsorption amount is in the range of 0.7 times or more of the saturated adsorption amount, preferably 0.8 times or more, more preferably 0.9 times or more.

  As a standard of the number of times that the washing process 1 is repeated, a range of 1 to 5 times can be mentioned. An operation exceeding the number of washings of 5 times is not industrially preferable because it leads to complicated operations and an increase in the amount of solvent used for production. If the excess cationic polymer dispersant cannot be removed even after repeating the washing step 1 5 times, review the washing time, review the washing solvent (A) used for washing, and contact the washing solvent (A). It is desirable to review the method.

  The washing solvent (A) that can be used in the washing step 1 is not limited as long as the excess cationic polymer dispersant can be dissolved, but the PPS-C fine particles include the solvent (A) used in the step 1. Since it may be contained, it is desirable that the solvent be miscible with the solvent (A).

  Examples of such washing solvent (A) include water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, chloroform, tetrahydrofuran, acetonitrile, N-methyl-2-pyrrolidone (NMP), Examples include diethylene glycol, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol dimethyl ether, toluene, and hexane. Among these, water, methanol, ethanol, n-propyl alcohol, and isopropyl alcohol are preferable, water or ethanol is more preferable, and water is particularly preferable.

[Removal step 1]
The cationic polymer dispersant adsorbing PPS fine particles, which are characteristic of the PPS fine particles of the embodiment of the present invention and hardly contain volatile components, are obtained from the PPS-C fine particles obtained in Step 1 (in some cases, the washing step 1). Is obtained by removing (removal step 1). In addition, when not performing the washing | cleaning process 1, the PPS-C microparticles | fine-particles obtained at the process 1 are solid-liquid-separated by usual well-known methods, such as filtration, vacuum filtration, pressure filtration, centrifugation, centrifugal filtration, spray drying. After that, it is desirable to use for the cleaning process 1.

  The volatile component removed here is mainly the solvent (A) remaining in the PPS-C fine particles, and in some cases also includes the cleaning solvent (A). By treating these volatile components so that the content of the volatile components is less than 50% by mass in the PPS-C fine particles, the PPS-C fine particles containing almost no volatile components of the embodiment of the present invention can be obtained.

  In the embodiment of the present invention, the phrase “substantially containing no volatile component” means that the volatile component obtained as a weight reduction rate when the temperature is increased from 20 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere. It means that the content is less than 50% by mass in the PPS-C fine particles.

  The means and conditions for removing the volatile component are not particularly limited as long as the content of the volatile component can be less than 50% by mass in the PPS-C fine particles. For example, a method of removing volatile components by a generally known drying method such as vacuum drying, freeze drying, natural drying, fluidized bed drying, drum drying, hot air drying, cold air drying, etc .; Examples include a method for removing components; a method for replacing volatile components with a high boiling point solvent having a boiling point of 200 ° C. or higher, and the like.

  It is also possible to use a high-boiling solvent having a boiling point of 200 ° C. or higher as the washing solvent (A) in the washing step 1 and to make the washing step 1 also function as the removal step 1.

  As a means of the removal step 1, since the volatile component can be removed more efficiently, the removal by the drying method is preferable.

  However, the removal step 1 is preferably performed at 200 ° C. or lower in order to prevent the cationic polymer dispersant from being decomposed.

  From the viewpoint that volatile components can be efficiently removed even at temperatures below such temperatures, means for removing volatile components in removal step 1 include vacuum drying, freeze drying, fluidized bed drying, drum drying, hot air among the removal by drying. Drying is preferable, vacuum drying, freeze drying, and fluidized bed drying are more preferable, and vacuum drying or freeze drying is particularly preferable.

  By removing the volatile components in the removal step 1 as described above, the temperature was increased from 20 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./min in a nitrogen atmosphere by TG-DTA measurement. PPS-C fine particles in which the content of volatile components calculated as the weight reduction rate is less than 50% by mass in the PPS-C fine particles are obtained.

  The content of volatile components in the PPS-C fine particles is preferably less than 30% by mass, more preferably less than 15% by mass, further preferably less than 10% by mass, particularly preferably less than 7.5% by mass, and most preferably 5% by mass. The lower limit is ideally 0% by mass.

  By setting the content of the volatile component to less than 50% by mass, the PPS fine particles according to the embodiment of the present invention are introduced into the dispersion medium and redispersed to form a dispersion. It can be reduced that the medium and the residual solvent are separated without being mixed, and the PPS fine particles of the embodiment of the present invention cause poor dispersion.

<Method for producing PPS-CA fine particles>
The PPS fine particles according to the embodiment of the present invention can be PPS-C-A fine particles obtained by further adsorbing an anionic surfactant to PPS-C fine particles obtained by adsorbing a cationic polymer dispersant on the fine particle surface. .

  The production method of the PPS-C-A fine particles is not particularly limited. For example, the step of bringing the fine particles and the anionic surfactant into contact with each other in a solvent by the same method as the production method of the PPS-C fine particles (step 2a or later described) It can be obtained by a method including a step 2) corresponding to the step 2b and a step of removing the solvent. Preferable methods for producing PPS-CA fine particles can be roughly divided into the following two methods.

In the first method, the operation of adsorbing the cationic polymer dispersant and the anionic surfactant to the raw material PPS fine particles is performed in the same solvent (B). The first method includes a third step of bringing the raw material PPS fine particles, the cationic polymer dispersant, and the anionic surfactant into contact in the solvent (B), and after the third step, the cationic polymer dispersion And a fourth step of removing the solvent (B) from the raw material PPS fine particles brought into contact with the agent and the anionic surfactant. The “third step” corresponds to “step 2a” described later. The “fourth step” corresponds to “removal step 2” described later. The solvent (B) corresponds to the second solvent (B) in [Means for Solving the Invention].

In the second method, after the cationic polymer dispersant is adsorbed on the raw material PPS fine particles, the solvent is changed to further adsorb the anionic surfactant. In the second method, the first step of bringing the raw material PPS fine particles and the cationic polymer dispersant into contact with each other in the solvent (A) and the raw material PPS fine particles brought into contact with the cationic polymer dispersant into the solvent (A) A second step of removing anionic surfactant, a fifth step of bringing the anionic surfactant into contact with the raw material PPS fine particles contacted with the cationic polymer dispersant in the solvent (C), and the cationic polymer dispersant And a sixth step of removing the solvent (C) from the raw material PPS fine particles brought into contact with the anionic surfactant. The first and second steps are the same steps as the first and second steps in the method for producing PPS-C fine particles. The “fifth step” corresponds to “step 2b” described later. The “sixth step” corresponds to “removal step 2” described later. Further, as will be described later, the “second step” and the “sixth step” may be the same step. The solvent (C) corresponds to the third solvent (C) in [Means for Solving the Invention].

[Step 2a]
The PPS fine particles (PPS-CA fine particles) adsorbed with the anionic surfactant are brought into contact with the raw material PPS fine particles, the cationic polymer dispersant, and the anionic surfactant in the solvent (B) in Step 2a. Can be obtained. By contacting each in the solvent (B), the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles by electrostatic interaction, and the anionic surfactant is adsorbed on the surface of the raw material PPS fine particles. It adsorbs by exhibiting electrostatic interaction with the adsorbed cationic polymer dispersant. Thereby, it is considered that the PPS-CA fine particles in which the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles and further the anionic surfactant is adsorbed are obtained.

  As the solvent (B) used in the step 2a, the raw material PPS fine particles and the cationic polymer dispersant exhibit an electrostatic interaction, and the cationic polymer dispersant and the anionic surfactant are electrostatic. It must be a solvent that exhibits interaction.

  Examples of such a solvent (B) include water, lower alcohols such as methanol, ethanol, n-propyl alcohol, and isopropyl alcohol, and water is particularly preferable.

  In the step 2a, regarding the method of bringing the cationic polymer dispersant and the anionic surfactant into contact with the raw material PPS fine particles in the solvent (B), the PPS-CA fine particles according to the embodiment of the present invention can be obtained. There is no limit. For example, a method similar to the method of bringing the cationic polymer dispersant into contact with the raw material PPS fine particles in the solvent (A) in Step 1 can be employed.

  Regarding the order in which the raw material PPS fine particles, the cationic polymer dispersant, and the anionic surfactant are brought into contact with each other in the solvent (B), they are brought into contact with each other as long as the PPS-CA fine particles according to the embodiment of the present invention are obtained. There is no limit to the order. In order to efficiently obtain PPS-CA fine particles in which the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles and further an anionic surfactant is adsorbed, the raw material PPS fine particles are added to the solvent (B). Thereafter, a method of bringing the raw material PPS fine particles, the cationic polymer dispersant, and the anionic surfactant into contact in the solvent (B) is preferable. Further, it is more preferable to contact the anionic surfactant after contacting the raw material PPS fine particles and the cationic polymer dispersant in the solvent (B).

  When the cationic polymer dispersant and the anionic surfactant are brought into contact with each other in the solvent (B) before contacting with the raw material PPS fine particles, the cationic polymer dispersant and the anionic surfactant form an aggregate. There is a possibility that the efficiency of adsorption to the raw material PPS fine particles will decrease.

  The cationic polymer dispersant and the anionic surfactant may be brought into contact with each other in advance in a state where each of them is dissolved in a predetermined amount of the solvent (B), or both of them may be brought into the solvent (B) in a bulk state. In addition, they may be contacted by dissolving them.

[Step 2b]
The PPS-CA fine particles adsorbed with the anionic surfactant adsorbed the cationic polymer dispersant in the solvent (C) as described above in addition to the first method including the step 2a. It can be produced by the second method comprising the step 2b of bringing the anionic surfactant into contact with the fine particles.

  Here, prior to the step 2b, the cationic polymer dispersant is contacted with the raw material PPS fine particles in the solvent (A) in the same manner as in the production method of the PPS-C fine particles (step 1), and then the cationic high The solvent (A) may be removed from the raw material PPS fine particles brought into contact with the molecular dispersant by any of the methods described in the removing step 1. Then, PPS-CA fine particle can be obtained by performing the process 2b which makes anionic surfactant contact the raw material PPS fine particle which contacted the cationic polymer dispersing agent in a solvent (C).

  By doing so, the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles by electrostatic interaction in the solvent (A), and then the anionic surfactant is used as the raw material in the solvent (C). Adsorption is caused by electrostatic interaction with the cationic polymer dispersant adsorbed on the surface of the PPS fine particles. As a result, it is considered that PPS-CA fine particles in which the cationic polymer dispersant is adsorbed on the surface of the raw material PPS fine particles and further the anionic surfactant is adsorbed are obtained.

  The solvent (A) used in Step 1 performed prior to Step 2b can be selected from the solvent (A) described in Step 1 described in the method for producing PPS-C fine particles.

As the solvent (C), a solvent in which the cationic polymer dispersant and the anionic surfactant exhibit an electrostatic interaction in the solvent can be used. When the fine particles adsorbing the cationic polymer dispersant and the anionic surfactant are brought into contact with each other in the solvent (C), the solvent residue used in the previous step may be contained. (C) is desirably mixed with the solvent (A). Examples of such a solvent (C) include water, lower alcohols such as methanol, ethanol, n-propyl alcohol, and isopropyl alcohol, and water is particularly preferable.

  A method of contacting the raw material PPS fine particles in the solvent (A) in the step (1) for producing the PPS-C-A fine particles, and a cationic polymer in the solvent (C) in the step 2b The method of bringing the anionic surfactant into contact with the raw material PPS fine particles that have been brought into contact with the dispersant is not limited as long as the PPS-CA fine particles according to the embodiment of the present invention can be obtained. For example, a method similar to Step 1 in the method for producing PPS-C fine particles can be employed.

  In step 2b, after bringing the raw material PPS fine particles and the cationic polymer dispersant into contact with each other in the solvent (A) (step 1), the solvent (A) is removed from the raw material PPS fine particles brought into contact with the cationic polymer dispersant. Prior to the removal step (removal step 1), the cleaning step 1 may be performed as necessary.

  The excess cationic polymer dispersant that can be generated by contact in the solvent (A) may inhibit the anionic surfactant from adsorbing to the cationic polymer dispersant adsorbed on the surface of the PPS fine particles. Therefore, the anionic surfactant can be adsorbed more efficiently by removing the excess cationic polymer dispersant in the washing step 1 and then subjecting it to adsorption of the anionic surfactant (step 2b). In that case, it is preferable to select each solvent in such a combination that the washing solvent (A) and the solvent (C) used in the washing step 1 are mixed.

  The concentration of the raw material PPS fine particles in Step 2a, Step 1 and Step 2b for producing PPS-C-A fine particles is the same as in Step 1 in the method for producing PPS-C fine particles based on the solvent used in each step. Concentration. Moreover, the time for each of the above steps can also be set in the same manner as in step 1 in the method for producing PPS-C fine particles.

  Further, the concentration of the cationic polymer dispersant used in Step 2a and Step 1 for producing PPS-CA fine particles is also based on the amount of raw material PPS fine particles used in each step. It can carry out according to the method as described in the process 1 in this manufacturing method. The concentration of the cationic polymer dispersant is preferably controlled so that the obtained PPS-C-A fine particles contain almost no excess cationic polymer dispersant.

  The concentration of the anionic surfactant in the steps 2a and 2b can be 0.1 to 200 parts by mass with respect to 100 parts by mass of the raw material PPS fine particles used in each step.

  The lower limit concentration of the anionic surfactant in the steps 2a and 2b is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 2.8 with respect to 100 parts by mass of the raw material PPS fine particles. It is at least 3.5 parts by mass, particularly preferably at least 3.5 parts by mass, and particularly preferably at least 4 parts by mass. Further, the upper limit concentration is preferably 150 parts by mass or less, more preferably 125 parts by mass or less, further preferably 100 parts by mass or less, particularly preferably 75 parts by mass or less, and extremely preferably. 60 parts by mass or less.

  When the concentration of the anionic surfactant is less than 0.1 parts by mass, the adsorption amount of the anionic surfactant is reduced, the effect of improving the affinity with the dispersion medium is not exhibited, and the effect of improving the redispersibility of the fine particles is achieved. Since it does not appear, it is not preferable.

  On the other hand, the range in which the concentration of the anionic surfactant exceeds 200 parts by mass is the range in which the amount of the added anionic surfactant clearly exceeds the saturated adsorption amount. The excess anionic surfactant exceeding the saturated adsorption amount does not participate in the electrostatic interaction with the cationic polymer dispersant, and becomes an excess anionic surfactant. It is not preferred to use an activator.

  The PPS-CA fine particles obtained in the step 2a or 2b are likely to contain an excess anionic surfactant depending on the particle diameter of the raw material PPS fine particles and the cationic polymer dispersant used. For this reason, it is desirable to perform a step of removing the solvent used in each step after performing a washing step 2 described later for removing excess anionic surfactant as necessary.

  In addition, in order to simplify the manufacturing method of PPS-CA fine particles, about the process 2a or 2b, the density | concentration of an anionic surfactant shall be 0.1-50 mass parts per 100 mass parts of raw material PPS microparticles | fine-particles. it can. By setting the concentration of the anionic surfactant within the above range, it is possible to obtain PPS-CA fine particles containing almost no excess anionic surfactant. Such PPS-C-A fine particles can be subjected to a solvent removal step 2 described later without going through a cleaning step 2 described later.

  As used herein, the phrase “contains little excess anionic surfactant” means that the adsorption amount of the anionic surfactant on the PPS-CA fine particles calculated by TG-DTA measurement is the saturation of the anionic surfactant. It means a range that does not exceed 1.5 times the amount of adsorption. That is, it means that the amount of excess anionic surfactant does not exceed 50% by mass of the saturated adsorption amount.

  The amount of excess anionic surfactant should be small, preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, and particularly preferably 10% by mass of the saturated adsorption amount. Controlling the amount of anionic surfactant used in adsorption steps 2a and 2b so that the content of excess anionic surfactant in the PPS-CA fine particles obtained after steps 2a and 2b is in the above range. Is preferred.

  The concentration of the anionic surfactant in the steps 2a and 2b can be, for example, 0.1 to 50 parts by mass with respect to 100 parts by mass of the raw material PPS fine particles. The lower limit concentration of the anionic surfactant in the steps 2a and 2b is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 2 parts by mass or more with respect to 100 parts by mass of the raw material PPS fine particles. It is 8 parts by mass or more, particularly preferably 3.5 parts by mass or more, and extremely preferably 4 parts by mass or more. Further, the upper limit concentration is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, further preferably 20 parts by mass or less, particularly preferably 15 parts by mass or less, and extremely preferably. 12.5 parts by mass or less.

  When the concentration of the anionic surfactant in steps 2a and 2b is less than 0.1 parts by mass, the adsorption amount of the anionic surfactant is reduced, the effect of improving the affinity with the dispersion medium is not exhibited, and Since the effect of improving dispersibility does not appear, it is not preferable.

  On the other hand, the range in which the concentration of the anionic surfactant exceeds 50 parts by mass is a range in which the obtained PPS-CA fine particles can contain excess anionic surfactant. That is, the adsorption amount of the anionic surfactant measured by TG-DTA may exceed 1.5 times the saturated adsorption amount. In such a case, the PPS-C- obtained in Step 2a or 2b It becomes necessary to apply the A fine particles to the cleaning step 2.

[Washing process 2]
If necessary, the PPS-CA fine particles obtained in the step 2a or 2b are washed with a washing solvent (B) to remove excess cationic polymer dispersant and / or excess anionic surfactant. It can use for the process to perform (cleaning process 2).

  The washing step 2 can be performed in the same manner as the washing step 1 except that the washing solvent (B) is used.

  The washing step 2 is desirably repeated until the adsorption amounts of the cationic polymer dispersant and the anionic surfactant adsorbed on the PPS-CA fine particles obtained after the washing are equal to the respective saturated adsorption amounts.

  The washing solvent (B) that can be used in the washing step 2 is not limited as long as it is a solvent in which the excess cationic polymer dispersant is dissolved and the excess anionic surfactant is dissolved. However, since the PPS-CA fine particles obtained from step 2a or 2b contain the solvent (B) or solvent (C) used in each step, it is desirable that the solvent be miscible with these solvents.

  Examples of such washing solvent (B) include water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, chloroform, tetrahydrofuran, acetonitrile, N-methyl-2-pyrrolidone (NMP), Examples include diethylene glycol, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, triethylene glycol dimethyl ether, toluene, and hexane. Among them, water, methanol, ethanol, n-propyl alcohol, and isopropyl alcohol are preferable, and water or ethanol is more preferable. Water is particularly preferred.

[Removal step 2]
The PPS-C-A fine particles obtained from the step 2a or 2b are subjected to a cleaning step 2 as necessary, and then the solvent used in each step is removed in the removal step 2, whereby the PPS according to the embodiment of the present invention. PPS-CA fine particles containing almost no volatile component, which is a feature of the fine particles, can be obtained.

  The volatile component removed here is mainly the solvent (B) or solvent (C) remaining in the PPS-C-A fine particles, and in some cases also includes the cleaning solvent (B). By treating these volatile components so that the content of the volatile components is less than 50% by mass in the PPS-CA fine particles, the PPS-CA fine particles containing almost no volatile components of the embodiment of the present invention can be obtained. can get.

  In the embodiment of the present invention, the phrase “substantially containing no volatile component” means that the volatile component obtained as a weight reduction rate when the temperature is increased from 20 ° C. to 200 ° C. at a rate of temperature increase of 10 ° C./min. It means that the content is less than 50% by mass in the PPS-CA fine particles.

  In addition, the means and conditions for removing volatile components can be performed in the same manner as in the removing step 1 in the method for producing PPS-C fine particles.

  In the above description, in the second method relating to the production of PPS-CA fine particles, prior to step 2b, the step of removing the solvent (A) from the raw material PPS fine particles contacted with the cationic polymer dispersant ( Although the removal step 1) is performed, a different configuration may be used. For example, after step 1, step 2b may be performed without performing removal step 1 (or further cleaning step 1). In this case, in the removing step 2 performed after the step 2b, the solvent (A) and the solvent (C) used in the step 1 and the step 2b are removed from the PPS-CA fine particles. That is, in this case, the “removal step 2” corresponds to the “second step” and the “sixth step” in [Means for Solving the Problems]. In this case, after step 2b, prior to removal step 2, washing step 2 may be performed as necessary to remove the excess cationic polymer dispersant and excess anionic surfactant.

  When removing the volatile component by the drying method described in the removing step 1, in order to prevent the cationic polymer dispersant and / or the anionic surfactant from being decomposed, the temperature is 200 ° C. or lower. Preferably it is done.

<Dispersion and resin composition>
The PPS fine particles of the embodiment of the present invention can be made into a dispersion liquid in addition to various solvents, or can be mixed with a resin or the like to make a resin composition.

  For example, in the case of a dispersion, the PPS microparticles of the embodiment of the present invention have a good affinity with the medium due to the action of the cationic polymer dispersant and, depending on the mode, the action of the anionic surfactant. In addition to the above, it is possible to suppress the aggregation of the dispersant-adsorbed PPS fine particles, and to easily become familiar with the medium and achieve a dispersed state.

  The solvent (dispersion medium) in which the PPS fine particles of the embodiment of the present invention can be dispersed depends on, for example, the type of cationic polymer dispersant and the type of anionic surfactant depending on the mode. Examples include solvents, aromatic hydrocarbon solvents, ester solvents, halogen solvents, ketone solvents, alcohol solvents, aprotic polar solvents, carboxylic acid solvents, ether solvents, ionic liquids, water, and the like.

  Specific examples of these dispersion media include the following. Examples of the aliphatic hydrocarbon solvent include pentane, hexane, heptane, octane, nonane, n-decane, n-dodecane, n-tridecane, tetradecane, cyclohexane, and cyclopentane. Examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, and 2-methylnaphthalene. Examples of the ester solvent include ethyl acetate, methyl acetate, butyl acetate, butyl propionate, and butyl butyrate. Examples of the halogenated hydrocarbon solvent include chloroform, bromoform, methylene chloride, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, hexafluoroisopropanol and the like. . Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, and methyl butyl ketone. Examples of alcohol solvents include methanol, ethanol, 1-propanol, 2-propanol and the like. Examples of aprotic polar solvents include N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), propylene carbonate, trimethyl phosphorus Examples include acids, 1,3-dimethyl-2-imidazolidinone, sulfolane and the like. Examples of the carboxylic acid solvent include formic acid, acetic acid, propionic acid, butyric acid, and lactic acid. Examples of the ether solvent include anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme, dimethoxyethane and the like. Examples of ionic liquids include 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-imidazolium acetate, 1-ethyl-3-methylimidazolium thiocyanate Etc.

  Among these, from the viewpoint of ease of handling in the industry, a preferable solvent as a dispersion medium is a dispersion medium selected from an aromatic hydrocarbon solvent, an alcohol solvent, a ketone solvent, and water, and is more preferable. Is a dispersion medium selected from an alcohol solvent, a ketone solvent and water, and more preferably a dispersion medium selected from an alcohol solvent and water. Specific examples of the preferable dispersion medium include a dispersion medium selected from toluene, methyl ethyl ketone, ethanol, isopropyl alcohol, and water. In addition, you may use these dispersion media in mixture of multiple types.

  Dispersions dispersed in these solvents can be used not only for various purposes in the form of dispersion, but also can be used by mixing the dispersion with other resins and other raw materials.

  In addition, when the PPS fine particles of the embodiment of the present invention are dispersed in the dispersion medium, a mechanical treatment can be performed to efficiently disperse the fine particles. Specifically, mechanical dispersion treatment is performed on a dispersion of PSP fine particles adsorbed with a dispersant using a wet atomizer such as an ultrasonic homogenizer, a homogenizer, a bead mill, a static mixer, or a wet jet mill. Can do.

  The particle concentration when the PPS fine particles of the embodiment of the present invention are dispersed in the dispersion medium to form a dispersion can be 0.01 to 80 parts by mass per 100 parts by mass of the dispersion.

  The lower limit of the particle concentration in the dispersion depends on the use of the dispersion, but is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, and further preferably 5 parts by weight or more, per 100 parts by weight of the dispersion. Especially preferably, it is 7.5 mass parts or more, Most preferably, it is 10 mass parts or more. Moreover, the upper limit becomes like this. Preferably it is 70 mass parts or less, More preferably, it is 60 mass parts or less, More preferably, it is 50 mass parts or less, Most preferably, it is 40 mass parts or less, Most preferably, it is 30 mass parts or less.

  When the particle concentration in the dispersion is less than 0.01 parts by mass, the amount of the dispersion used may increase when the dispersion is applied to various applications because the concentration of the fine particles is low. When the amount of the dispersion used is increased, the amount of the solvent used as the dispersion medium is also increased, which is not preferable. On the other hand, when the particle concentration exceeds 80 parts by mass, the viscosity of the dispersion liquid is increased, and the handleability is deteriorated.

  The PPS fine particles of the embodiment of the present invention exhibit a volume average particle diameter of 0.05 to 10 μm in the dispersion. Depending on the type of the cationic polymer dispersant adsorbed on the surface of the fine particles, or depending on the type of the anionic surfactant in some embodiments, the volume average particle size in the dispersion is preferably 0.05 to 7.5 μm. More preferably, it is 0.05-5 micrometers, More preferably, it is 0.05-2.5 micrometers, Especially preferably, it is 0.05 micrometer-1 micrometer.

  In a dispersion having a volume average particle diameter exceeding 10 μm in the dispersion, the fine particles remarkably exhibit gravity sedimentation, resulting in poor dispersion stability.

  Here, the volume average particle diameter in the dispersion refers to the average particle diameter calculated on a volume basis among the particle diameters of the fine particles in the dispersion medium measured with a laser diffraction particle size distribution meter.

  Examples of the resin that can be used as a medium when forming the resin composition containing the PPS fine particles of the embodiment of the present invention include thermoplastic resins and thermosetting resins.

  The PPS microparticles of the embodiment of the present invention are microparticles in which a cationic polymer dispersant is adsorbed on the surface of the microparticles and hardly contain volatile components such as a solvent. It is possible to obtain a dispersion by simply introducing fine particles into a desired medium and redispersing them. The cationic polymer dispersant adsorbed on the surface of the fine particles exhibits a high affinity with the medium and builds a high steric barrier between the fine particles, so that the aggregation of the fine particles is suppressed and the fine particles are contained in the medium at a higher concentration. Can be dispersed. In addition, the PPS microparticles of the embodiment of the present invention have a cationic polymer dispersant adsorbed on the surface of the microparticles bonded to the surface of the raw material PPS microparticles by electrostatic interaction, and the content of excess cationic polymer dispersant. Therefore, it is possible to re-disperse in the medium, and at the same time, even if re-dispersed in the medium, it is possible to suppress the adverse effects on the product due to the excessive dispersant causing contamination. In addition, in a preferred aspect, the PPS microparticles of the embodiment of the present invention can adsorb an anionic surfactant on the surface of the microparticles in addition to the cationic polymer dispersant. It can be dispersed in a wider range of media.

  Therefore, the PPS fine particles of the embodiment of the present invention can be used practically by being mixed with any medium as described above, as well as being used alone as the fine particles of the PPS resin.

  Specifically, molding materials represented by injection molding, microfabrication, etc .; electronic / electrical material component parts, electronics product casing parts members obtained using the materials; thickeners during molding, molding Additives such as dimensional stabilizers; coatings in the form of dispersions, coatings, paints, coating materials, lubricants; rapid prototyping, rapid manufacturing and additive manufacturing materials; as powders Fluidity improvers, lubricants, abrasives and thickeners; plastic films, sheet slipperiness improvers, antiblocking agents, gloss modifiers and matte finishes; plastic films, sheets, lens light diffusion Various modifiers such as materials, surface hardness improvers and toughness improvers; various inks; toner gloss modifiers, matte finishes Additives for applications such as gloss control agents for various paints, additives for applications such as matte finish materials, spacers for liquid crystal display operations, fillers for chromatography, base materials and additives for cosmetics, and chemical reactions It can be used for applications such as a catalyst and a carrier; a gas adsorbent.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these.

  Tables 1 and 2 collectively show the conditions and various measurement results of the PPS fine particles of each Example and Comparative Example. Various measurement methods, methods for producing PPS fine particles of each example and comparative example, and measurement results will be described in order.

[Measurement of adsorption amount]
Raw material PPS fine particles, cationic polymer dispersant, anionic surfactant, PPS-C fine particles, and PPS-C-A fine particles, simultaneous differential heat and thermogravimetric measurement device (TG-DTA; DTG manufactured by Shimadzu Corporation) −60), the thermal decomposition behavior (weight loss and endothermic generation) was measured when the temperature was raised from 20 ° C. to 500 ° C. under the conditions of a temperature rising rate of 10 ° C./min and a nitrogen atmosphere.

  In order to measure the saturated adsorption amount, first, for the PPS-C fine particles, the adsorption amount of the cationic polymer dispersant was measured by changing the concentration of the cationic polymer dispersant, and an adsorption isotherm was created. . Moreover, about the PPS-CA fine particle, the density | concentration of the anionic surfactant was changed, the adsorption amount of the anionic surfactant was measured, and the adsorption isotherm was created. When the adsorption isotherm shows a single-layer adsorption model, the saturated adsorption amount is the value when the adsorption amount of the cationic polymer dispersant or anionic surfactant does not change regardless of the concentration. . When the adsorption isotherm showed a multilayer adsorption model, each fine particle was washed until the adsorption isotherm became a single-layer adsorption model pattern showing saturation, and then the value showing saturation was taken as the saturated adsorption amount.

[Measurement of volatile content]
Using a differential heat / thermogravimetric simultaneous measurement device (TG-DTA; DTG-60 manufactured by Shimadzu Corporation), a sample 10 mg precisely weighed from 20 ° C. to 200 ° C. under a temperature increase rate of 10 ° C./min under a nitrogen atmosphere. The weight reduction rate when the temperature was raised to ° C. was defined as the volatile component content in each sample fine particle.

[Measurement of zeta potential]
For the measurement of the zeta potential of the fine particles in the liquid, a measurement liquid having a pH of 7.9 using an aqueous sodium hydroxide solution and hydrochloric acid and an ion concentration of 1 mmol / L by adding sodium chloride was used. To this measurement liquid, 0.1 mass part of particles per 100 parts by mass of the measurement liquid was added, and using a measurement cell, a zeta electrometer (Zeta electrometer ELS-Z2 manufactured by Otsuka Chemical Co., Ltd.) Measurement was performed three times at a setting of 25 ° C. The arithmetic average value of the obtained measured values was used as the zeta potential of the fine particles in the measurement liquid.

[Measurement of average primary particle size]
In order to obtain the average primary average particle diameter Dd of the raw material PPS fine particles, the raw material PPS fine particles were 10,000 times larger using a scanning electron microscope (FE-SEM; scanning electron microscope JSM-6301NF manufactured by JEOL Ltd.). The diameter (particle diameter) was measured for 100 raw material PPS fine particles. At that time, in order to obtain an accurate number average particle size that reflects the variation in particle size, the particle size is measured by observing with a magnification and a field of view that two or more and less than 100 fine particles appear in one image. did. Subsequently, the average primary particle size was calculated by calculating the arithmetic average of 100 fine particles with the following formula. When the fine particles were not perfectly circular on the image (for example, when they were oval), the longest diameter was measured as the particle diameter. Further, when an aggregate in which the fine particles gathered irregularly was formed, the diameter of the fine particles of the smallest unit forming the aggregate was measured as the particle diameter. However, when the aggregate was a fusion of a plurality of fine particles and the boundary between the fine particles was not clear, the maximum diameter of the fusion product was measured as the particle diameter.

（式中、Ｒ_ｉは微粒子個々の粒子径を表わし、Ｄ_ｐは平均１次粒子径を表わす。ｎは測定数を表わし、各実施例では１００とした。）

(In the formula, R _i represents the particle diameter of each fine particle, D _p represents the average primary particle diameter, n represents the number of measurements, and is 100 in each example.)

[Measurement of sphericity]
The sphericity of the raw material PPS fine particles is an arithmetic average value of the sphericity of 30 randomly selected fine particles in the image observed by FE-SEM, and was calculated according to the following formula. The sphericity is the ratio of the major axis (maximum diameter) of each fine particle to the minor axis perpendicular to the major axis at the center of the major axis, and was calculated according to the following formula.

（式中、Ｓ_ｍは平均真球度（％）を表わし、Ｓ_ｉは微粒子個々の真球度を表わし、ａ_ｉは微粒子個々の短径を表わし、ｂ_ｉは微粒子個々の長径を表わす。ｎは測定数を表わし、各実施例では３０とした）。

(Wherein S _m represents the average sphericity (%), S _i represents the sphericity of each fine particle, a _i represents the short diameter of each fine particle, and b _i represents the long diameter of each fine particle. n represents the number of measurements, which was 30 in each example).

[Measurement of volume average particle diameter in dispersion]
The volume average particle diameter of the dispersant-adsorbed PPS fine particles in the dispersion is mixed with the fine particles and the dispersion medium so that the concentration becomes 0.1 parts by mass per 100 parts by mass of the dispersion, and then subjected to ultrasonic dispersion treatment and laser diffraction. It measured using the type | formula particle size distribution analyzer (SALD-2100 by Shimadzu Corporation). The average value of the obtained volume-based particle size distribution was defined as the volume average particle diameter Dv.

[Ultrasonic dispersion processing]
Using an ultrasonic homogenizer (US-150E manufactured by Nihon Seiki Seisakusho Co., Ltd.), the tip of the tip was in contact with the dispersion with a configuration of output 150 W, frequency 19.5 kHz ± 0.5 kHz, vibration transmission tip φ7 mm, and 1 Treated for minutes.

[Uniformity of slurry]
After adding a predetermined amount of the dispersant-adsorbed PPS fine particles to the dispersion medium, the dispersion slurry subjected to the ultrasonic dispersion treatment is visually observed as to whether or not the dispersant-adsorbed PPS fine particles are uniformly dispersed. evaluated.
A: The dispersant adsorbed PPS fine particles do not appear to be lumpy in the slurry and are uniformly leveled, and no separation from the dispersion medium is observed.
B: Dispersant-adsorbed PPS fine particles are not separated from the dispersion medium, but appear to form lumps having a size of less than 1 mm in the slurry and do not have a uniform appearance.
C: Part of the dispersant-adsorbed PPS fine particles is mixed with the dispersion medium, but a lump with a size of 1 mm or more is observed, and the slurry does not have a uniform appearance.
D: Dispersant-adsorbed PPS fine particles are not adapted to the dispersion medium and are floating or settled in the dispersion medium, and the fine particles are separated from the dispersion medium.

[Reference Example 1] Polymerization of raw material PPS resin (dehydration process)
In a 70 L autoclave with a stirrer and a bottom plug valve, 25 parts by mass of 47.5% sodium hydrosulfide, 9 parts by mass of 96% sodium hydroxide, 34 parts by mass of N-methyl-2-pyrrolidone (NMP), and 32 parts by mass of water The reaction vessel was cooled to 200 ° C. after distilling 45 parts by mass of water and 0.8 parts by mass of NMP while gradually heating to 245 ° C. over about 3 hours while passing nitrogen at normal pressure. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.06 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.02 mol per mol of the charged alkali metal sulfide.

(Polymerization process)
Next, 32 parts by mass of p-dichlorobenzene and 28 parts by mass of NMP are added to 100 parts by mass of the reaction product obtained in the dehydration step, and the reaction vessel is sealed under nitrogen gas and stirred at 240 rpm. However, the temperature was raised from 200 ° C. to 270 ° C. at a rate of 0.6 ° C./min. Then, it reacted at 270 ° C. for 100 minutes. Thereafter, the bottom plug valve of the autoclave was opened, and the contents were discharged into a container equipped with a stirrer while being pressurized with nitrogen over 15 minutes, and then NMP was removed by stirring at 250 ° C.

(Washing process)
The solid obtained in the polymerization step and 230 parts by mass of water (relative to 100 parts by mass in the dehydration step) were placed in an autoclave equipped with a stirrer and washed at 70 ° C. for 30 minutes. Thereafter, 230 parts by mass of water (based on 100 parts by mass in the dehydration step) heated to 70 ° C. was poured into the glass filter and suction filtered to obtain a cake. The obtained cake and 270 parts by mass of water (with respect to 100 parts by mass in the total amount of the dehydration step) were charged into an autoclave equipped with a stirrer, and the inside of the autoclave was replaced with nitrogen, and then the temperature was raised to 190 ° C. and held for 30 minutes. Thereafter, the autoclave was cooled and the contents were taken out.

(Drying process)
The content taken out was suction filtered with a glass filter, and then 230 parts by mass of water at 70 ° C. (to a total amount of 100 parts by mass in the dehydration step) was poured into the cake to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain a raw material PPS resin powder.

[Reference Example 2] Production of raw material PPS fine particles (dissolution process)
A 9.8 L autoclave (reaction tank) was fitted with a connecting pipe so that the valve could be opened and closed and the end of the pipe was positioned in the tank. In addition, as a poor solvent tank, a 50 L pressure tank was equipped with a stirrer, a condenser, and a gas vent pipe, and the other end of the connecting pipe of the reaction tank was placed in the tank. 3 parts by mass of the raw material PPS resin powder obtained in Reference Example 1 and 97 parts by mass of N-methyl-2-pyrrolidone obtained in Reference Example 1 were placed in a reaction tank, and the valve of the internal connecting pipe was sealed, followed by nitrogen substitution. The temperature was raised to 280 ° C. with stirring, followed by stirring for 30 minutes. The internal pressure (gauge pressure) at this time was 0.4 MPa.

(Precipitation process)
97 mass parts of water was put into the said poor solvent tank, and the front-end | tip of the connecting pipe by the side of a poor solvent tank was put in water. The poor solvent tank was ice-cooled and nitrogen gas was passed. At this time, the temperature of the poor solvent tank was 5 ° C. Subsequently, the valve of the connecting pipe on the reaction tank side was opened, and the solution was flash-cooled by jetting into the water of the poor solvent tank. This flash solution was put into 80 parts by mass of an aqueous magnesium acetate solution in which 0.38 parts by mass of magnesium acetate per 100 parts by mass of water was dissolved, stirred for 1 hour, and then allowed to stand for 5 hours for salting out. The reaction solution after salting out was subjected to solid-liquid separation with a centrifugal dehydrator to isolate the solid content. The solid content taken out was mixed with 25 parts by mass of ion-exchanged water, and then solid-liquid separated again with a centrifugal dehydrator to isolate the solid content. The same operation was repeated twice to remove the salt to obtain water-containing raw material PPS fine particles. It was 0.3 micrometer when the average primary particle diameter of the obtained raw material PPS microparticles | fine-particles was measured. The measurement result of the zeta potential was −42.4 m∨. Moreover, the water content of the raw material PPS fine particles in a water-containing state was 75% by mass when determined in the same manner as the content of volatile components.

<PPS-C fine particles>
[Example 1: Particle 1]
(Adsorption process)
In a 50 mL glass beaker, 58 parts by mass of water, 40 parts by mass of water-containing raw material PPS fine particles obtained in Reference Example 2, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., “Epomin (registered trademark)” SP-200, weight average molecular weight 10,000) 2 parts by mass, and stirred for 1 hour at 25 ° C. using a magnetic stirrer. Thereafter, the solution in the beaker was transferred to a centrifuge tube and centrifuged (40,000 G, 1 hour) to isolate water-containing PPS-C fine particles. The isolated water-containing PPS-C fine particles had an adsorption amount of polyethyleneimine measured by TG-DTA of 17 parts by mass per 100 parts by mass of raw material PPS fine particles, and the content of volatile components was 75% by mass.

(Washing process)
Subsequently, to the 100 mL beaker, water of isolated water-containing PPS-C fine particles and 150 parts by mass of water per 100 parts by mass of water-containing PPS-C fine particles (723 parts by mass per 100 parts by mass of raw material PPS fine particles) were added, After washing the fine particles by stirring for 0.5 hour at 25 ° C. using a magnetic stirrer, the PPS-C fine particles were isolated by the same operation as in the adsorption step. This washing operation was performed 3 times in total to remove excess polyethyleneimine. The amount of polyethyleneimine adsorbed per 100 parts by mass of the raw material PPS fine particles after each washing operation was 5.9 parts by mass after the first washing, 4.9 parts by mass after the second washing, and 4.7 masses after the third washing. Was part. The saturated adsorption amount of polyethyleneimine with respect to the raw material PPS fine particles obtained in Reference Example 2 was 4.8 parts by mass per 100 parts by mass of the raw material PPS fine particles as a result of obtaining an adsorption isotherm. From this result, it was confirmed that PPS-C fine particles with saturated adsorption of polyethyleneimine were obtained by washing.

(Drying process)
The PPS-C fine particles obtained in the washing step were vacuum dried at 50 ° C. for 12 hours to obtain PPS-C fine particles having a volatile component content of 1.6% by mass. The PPS-C fine particles obtained as described above are designated as Particle 1.

[Example 2: Particle 2]
(Adsorption process)
59.3 parts by weight of water, 40 parts by weight of water-containing raw material PPS fine particles obtained in Reference Example 2, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., 'Epomin (registered trademark)' SP-200, weight average molecular weight 10,000) It carried out similarly to Example 1 except having set it as 0.7 mass part. Subsequently, the washing step was omitted and the drying step was performed.

(Drying process)
Volatile components were removed from the fine particles isolated from the adsorption step in the same manner as in Example 1. The amount of polyethyleneimine adsorbed on the obtained PPS-C fine particles was 4.9 parts by mass per 100 parts by mass of raw material PPS fine particles, and it was confirmed that polyethyleneimine was saturatedly adsorbed. Moreover, the content rate of the volatile component was 1.5 mass%. The PPS-C fine particles obtained as described above are designated as Particle 2.

[Comparative Example 1: Particle 3]
(Adsorption process)
59.95 parts by mass of water, 40 parts by mass of water-containing raw material PPS fine particles obtained in Reference Example 2, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., “Epomin (registered trademark)” SP-200, weight average molecular weight 10,000) The same operation as in Example 1 was performed except that the amount was 0.005 part by mass. Subsequently, the washing step was omitted and the drying step was performed.

(Drying process)
The isolated fine particles were removed in the same manner as in Example 1 to remove volatile components. The amount of polyethyleneimine adsorbed on the obtained PPS-C fine particles was 0.05 parts by mass per 100 parts by mass of the raw material PPS fine particles, and the content of volatile components was 1.5% by mass. The PPS-C fine particles obtained as described above are referred to as particles 3.

[Comparative Example 2: Particle 4]
Using the water-containing raw material PPS fine particles obtained in Reference Example 2, isopropyl alcohol-containing PPS fine particles were prepared by the method described in Production Example 2 of Patent Document 3 (Japanese Patent Laid-Open No. 2011-122108). The liquid content of the isopropyl alcohol-containing PPS fine particles was 80% by mass in the method for measuring the amount of volatile components. Subsequently, according to the method described in Example 2 of Patent Document 3, 14.2 parts by mass of isopropyl-containing PPS fine particles, 10 parts by mass of a 10% by mass isopropyl alcohol solution of polyethyleneimine, and 75.8 parts by mass of isopropyl alcohol were added. And stirred. After stirring, fine particles were isolated by the same operation as in Example 1, and the amount of polyethyleneimine adsorbed and the content of volatile components were measured. As a result, the adsorption amount of polyethyleneimine was 31 parts by mass per 100 parts by mass of the raw material PPS fine particles, and the content of volatile components was 78% by mass. The obtained fine particles contain excess polyethyleneimine and have a high content of volatile components, which is not preferable for use. The PPS-C fine particles obtained as described above are referred to as particles 4.

[Comparative Example 3: Particle 5]
The raw material PPS fine particles in the water-containing state obtained in Reference Example 2 were treated in the same manner as in the drying step of Example 1, and then the content of volatile components was measured. As a result, the content of volatile components was 1.5% by mass. The PPS fine particles subjected to the above treatment are referred to as particles 5.

<PPS-CA fine particles>
[Example 3: Particle 6]
(Adsorption process)
In a 50 mL glass beaker, 82.5 parts by mass of water, 10 parts by mass of particle 1 and 7.5 parts by mass of oleic acid (manufactured by Tokyo Chemical Industry Co., Ltd., purity over 85.0%) are placed, and magnetic at 25 ° C. The mixture was stirred for 3 hours using a stirrer. Thereafter, the liquid in the beaker was transferred to a centrifuge tube and centrifuged (6,000 G, 0.5 hour) to isolate water-containing PPS-CA fine particles. The isolated water-containing PPS-CA fine particles had an oleic acid adsorption amount measured by TG-DTA of 61 parts by mass per 100 parts by mass of raw material PPS fine particles and a volatile component content of 73% by mass.

(Washing process)
Subsequently, in a 100 mL beaker, the water-containing PPS-CA fine particles isolated from the adsorption step and 200 parts by weight per 100 parts by weight of the water-containing PPS-CA fine particles (2 per 100 parts by weight of the raw material PPS fine particles). , 165 parts by mass) of ethanol was added, and the mixture was stirred for 0.5 hours at 25 ° C. using a magnetic stirrer to wash the fine particles. Thereafter, PPS-CA fine particles were isolated by the same operation as in the adsorption step. This washing operation was performed 3 times in total to remove excess oleic acid. The amount of oleic acid adsorbed after each washing operation was 23 parts by mass after the first washing, 8.1 parts by mass after the second washing, and 7.5 parts by mass after the third washing. In addition, the saturated adsorption amount of oleic acid with respect to the particles 1 was 7.6 parts by mass per 100 parts by mass of the raw material PPS fine particles as a result of obtaining an adsorption isotherm. From this result, it was confirmed that PPS-CA fine particles in which oleic acid was saturated and adsorbed were obtained by washing.

(Drying process)
After the PPS-CA fine particles obtained in the washing step were isolated, the volatile components were removed in the same manner as in Example 1, and the PPS-CA fine particles having a volatile component content of 5.2 mass%. Got. The PPS-CA fine particles obtained as described above are referred to as particles 6.

[Example 4: Particle 7]
(Adsorption process)
Except that 82.5 parts by mass of water, 10 parts by mass of particle 1 and 10 parts by mass of polyoxyethylene lauryl ether phosphate (manufactured by Toho Chemical Co., Ltd., Phosphanol RS-610) instead of oleic acid Performed as in Example 1. The isolated water-containing PPS-CA fine particles have an adsorption amount of polyoxyethylene lauryl ether phosphate measured by TG-DTA of 34 parts by mass per 100 parts by mass of raw material PPS fine particles, and the content of volatile components is 76 masses. %Met.

(Washing process)
Subsequently, in a 100 mL beaker, the water-containing PPS-CA fine particles isolated from the adsorption step and 200 parts by weight per 100 parts by weight of the water-containing PPS-CA fine particles (1 per 100 parts by weight of the raw material PPS fine particles). , 360 parts by mass) of ethanol was added, and the washing operation was performed three times in the same manner as in Example 3. The amount of polyoxyethylene lauryl ether phosphate adsorbed after each washing operation was 29 parts by mass after the first washing, 15 parts by mass after the second washing, and 9.0 parts by mass after the third washing. The saturated adsorption amount of polyoxyethylene lauryl ether phosphate with respect to the particles 1 was 8.4 parts by mass per 100 parts by mass of the raw material PPS fine particles as a result of obtaining an adsorption isotherm. From this result, it was confirmed that PPS-CA fine particles in which polyoxyethylene lauryl ether phosphoric acid was saturated and adsorbed were obtained by washing.

(Drying process)
After the PPS-CA fine particles obtained in the washing step were isolated, the volatile components were removed in the same manner as in Example 1, and the PPS-CA fine particles having a volatile component content of 2.2% by mass were removed. Got. The PPS-CA fine particles obtained as described above are referred to as particles 7.

[Example 5: Particle 8]
(Adsorption process)
In a 50 mL glass beaker, 25 parts by weight of water, 40 parts by weight of raw material PPS fine particles in a water-containing state obtained in Reference Example 2, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., “Epomin (registered trademark)” SP-200, weight average molecular weight 10 mass% aqueous solution of 10,000) and 30 mass parts of 3 mass% aqueous solution of polyoxyethylene lauryl ether phosphoric acid (manufactured by Toho Chemical Industry Co., Ltd., Phosphanol RS-610) at 25 ° C. The mixture was stirred for 1 hour using a magnetic stirrer. At this time, after mixing water and the raw material PPS microparticles | fine-particles, the polyethyleneimine aqueous solution was added, and the polyoxyethylene lauryl ether phosphoric acid aqueous solution was added following it. After stirring, the fine particles were isolated in the same manner as in Example 1, and then the washing step was omitted and the drying step was performed.

(Drying process)
Volatile components were removed from the fine particles isolated from the adsorption step in the same manner as in Example 1. The amount of polyethyleneimine adsorbed on the obtained PPS-CA fine particles was 4.8 parts by mass per 100 parts by mass of the raw material PPS fine particles, and the amount of polyoxyethylene lauryl ether phosphate adsorbed was 8 parts per 100 parts by mass of the raw material PPS fine particles. It was 8 parts by mass. Moreover, the content rate of the volatile component was 2.4 mass%. The PPS-CA fine particles obtained as described above are designated as particles 8.

[Comparative Example 4: Particle 9]
Fine particles were produced by adsorbing oleylamine, which is a cationic surfactant, on the surface of raw material PPS fine particles. Since oleylamine is a low molecular weight dispersant that does not correspond to the cationic polymer dispersant defined in the embodiment of the present application, the steric hindrance formed on the surface of the raw material PPS fine particles is that of the cationic polymer dispersant. Smaller than that.

(Adsorption process)
In a 50 mL glass beaker, 58.5 parts by mass of water, 40 parts by mass of water-containing raw material PPS fine particles obtained in Reference Example 2, and 1.5 parts by mass of oleylamine (Sigma Aldrich, purity 70%) were placed at 25 ° C. And stirred for 3 hours using a magnetic stirrer. Thereafter, the liquid in the beaker was transferred to a centrifuge tube and centrifuged (6,000 G, 0.5 hour) to isolate water-containing oleylamine-adsorbed PPS fine particles. The isolated water-containing fine particles had an oleylamine adsorption amount of 8.2 parts by mass per 100 parts by mass of the raw material PPS fine particles and a volatile component content of 75% by mass as measured by TG-DTA.

(Washing process)
Subsequently, in a 100 mL beaker, water-containing oleylamine-adsorbed PPS fine particles isolated from the adsorption step and 200 parts by mass per 100 parts by mass of water-containing oleylamine-adsorbed PPS fine particles (870 parts by mass per 100 parts by mass of raw material PPS fine particles) Ethanol was added and the same washing operation as in Example 3 was performed twice. The amount of oleylamine adsorbed after each washing operation was 4.0 parts by mass after one washing and 3.5 parts by mass after two washings. The saturated adsorption amount of oleylamine to the raw material PPS fine particles obtained in Reference Example 2 was 4.0 parts by mass per 100 parts by mass of the raw material PPS fine particles as a result of obtaining an adsorption isotherm. From this result, it was confirmed that PPS fine particles with saturated adsorption of oleylamine were obtained by washing.

(Drying process)
After the fine particles obtained in the washing step were isolated, volatile components were removed in the same manner as in Example 1 to obtain oleylamine-adsorbed PPS fine particles having a volatile component content of 1.7% by mass. The oleylamine-adsorbed PPS fine particles obtained as described above are defined as particles 9.

<Evaluation of dispersion>
Various PPS fine particles obtained in the above-mentioned examples and comparative examples were added to various dispersion media, subjected to ultrasonic treatment, and then a dispersion was prepared. Table 3 shows the results of measuring the volume average particle diameter of each dispersion using a laser diffraction particle size distribution meter.

  Subsequently, each fine particle obtained in the above Examples and Comparative Examples was added to a solvent at a predetermined particle concentration and subjected to ultrasonic dispersion treatment to prepare a dispersion (slurry) of PPS fine particles. Table 3 shows the results of the appearance evaluation of the uniformity of each slurry. In Table 3, the particle concentration represents the part by mass of each PPS fine particle per 100 parts by mass of the solvent. Each PPS fine particle obtained in the examples was well redispersed in each dispersion medium and could be easily slurried and had a smooth appearance.

Claims (14)

Polyphenylene sulfide fine particles,
0.1 to 30 parts by mass of a cationic polymer dispersant per 100 parts by mass of the raw polyphenylene sulfide fine particles are adsorbed on the surface of the raw polyphenylene sulfide fine particles containing polyphenylene sulfide, and
The content of the volatile component of the polyphenylene sulfide fine particles, the content of the volatile component calculated as a weight reduction rate when the polyphenylene sulfide fine particles 10 mg are heated from 20 ° C. to 200 ° C. in a nitrogen atmosphere, Polyphenylene sulfide fine particles characterized by being less than 50% by mass. 2. The polyphenylene sulfide fine particles according to claim 1, wherein the cationic polymer dispersant is a polyalkylene polyamine. 3. The polyphenylene sulfide fine particles according to claim 1, wherein an average primary particle diameter of the polyphenylene sulfide fine particles is 0.05 μm to 1 μm. The polyphenylene sulfide fine particles according to any one of claims 1 to 3, wherein the sphericity of the polyphenylene sulfide fine particles is 80 or more. The polyphenylene sulfide fine particles according to any one of claims 1 to 4, wherein an anionic surfactant is further adsorbed on the surface of the raw material polyphenylene sulfide fine particles. 6. The polyphenylene sulfide fine particles according to claim 5, wherein the anionic surfactant is one or more surfactants selected from fatty acids and polyoxyalkylene alkyl ether phosphoric acids. 7. The polyphenylene sulfide fine particles according to claim 5, wherein an adsorption amount of the anionic surfactant is 0.1 to 50 parts by mass per 100 parts by mass of the raw polyphenylene sulfide fine particles. A method for producing the polyphenylene sulfide fine particles according to any one of claims 1 to 4,
A first step of bringing the cationic polymer dispersant into contact with the raw polyphenylene sulfide fine particles in the first solvent (A);
After the first step, a second step of removing the first solvent (A) from the raw material polyphenylene sulfide fine particles contacted with the cationic polymer dispersant;
A process for producing polyphenylene sulfide fine particles, comprising: A method for producing the polyphenylene sulfide fine particles according to any one of claims 5 to 7,
A third step of bringing the cationic polymer dispersant and the anionic surfactant into contact with the raw material polyphenylene sulfide fine particles in the second solvent (B);
After the third step, a fourth step of removing the second solvent (B) from the raw polyphenylene sulfide fine particles in contact with the cationic polymer dispersant and the anionic surfactant;
A process for producing polyphenylene sulfide fine particles, comprising: A method for producing the polyphenylene sulfide fine particles according to any one of claims 5 to 7,
A first step of bringing the cationic polymer dispersant into contact with the raw polyphenylene sulfide fine particles in the first solvent (A);
After the first step, a second step of removing the first solvent (A) from the raw material polyphenylene sulfide fine particles contacted with the cationic polymer dispersant;
Before or after the second step, in the third solvent (C), the fifth step of bringing the anionic surfactant into contact with the raw material polyphenylene sulfide fine particles contacted with the cationic polymer dispersant. When,
After the fifth step, a sixth step of removing the third solvent (C) from the raw material polyphenylene sulfide fine particles brought into contact with the cationic polymer dispersant and the anionic surfactant; A method for producing polyphenylene sulfide fine particles, comprising: A polyphenylene sulfide fine particle dispersion in which the polyphenylene sulfide fine particles according to any one of claims 1 to 7 are dispersed in a dispersion medium. The polyphenylene sulfide fine particle dispersion according to claim 11, wherein the concentration of the polyphenylene sulfide fine particles in the dispersion is 0.01 to 80 parts by mass per 100 parts by mass of the dispersion. 13. The polyphenylene sulfide fine particle dispersion according to claim 11, wherein the polyphenylene sulfide fine particles in the dispersion have a volume average particle diameter of 0.05 μm to 10 μm. A resin composition containing the polyphenylene sulfide fine particles according to claim 1.

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