JP5589373B2 - Polyphenylene sulfide resin fine particle dispersion and method for producing the same - Google Patents

Description

  The present invention relates to a polyphenylene sulfide resin fine particle dispersion and a method for producing the same.

  Polyphenylene sulfide (hereinafter abbreviated as PPS) resin has excellent properties as an engineering plastic such as excellent heat resistance, chemical resistance, solvent resistance, and electrical insulation. Injection molding and extrusion molding It is used for various electrical / electronic parts, machine parts, automobile parts, etc. mainly in applications. Resins having such various excellent properties and dispersions thereof are in high demand in the fields of paints, adhesive materials, automobiles, electronic materials, etc., and the following production method is a method for obtaining a PPS resin fine particle dispersion. Has been reported.

  In Patent Document 1, there is a method of obtaining a PPS resin fine particle dispersion by dissolving PPS in an organic solvent such as NMP in the presence of an inorganic salt, followed by cooling, and mechanically grinding the obtained PPS with a bead mill or the like. It is disclosed. This method discloses that PPS resin fine particles having an average particle diameter of 1 μm or less can be obtained, and a stable dispersion can be obtained. In Patent Document 2, there is a method in which PPS is dissolved in an organic solvent such as NMP in the presence of a surfactant and then cooled, and the obtained PPS is mechanically pulverized by a bead mill or the like to obtain a PPS resin fine particle dispersion. It is disclosed. It is disclosed that PPS resin fine particles having an average particle diameter of 1 μm or less can be obtained by this method, and a stable dispersion can be obtained. In Patent Document 3, fine PPS resin fine particles are obtained by dissolving PPS in an organic solvent such as NMP and then flash cooling, and further finely dividing the PPS resin fine particles by mechanical pulverization or mechanical dispersion. A method for producing fine PPS resin fine particles and a method for obtaining a dispersion thereof are described.

  In these methods, 1 μm or less, so-called submicron sized PPS resin fine particles necessary for obtaining a stable PPS resin fine particle dispersion can be obtained, and the PPS resin fine particles can be dispersed in a solvent. The dispersions specifically shown in the examples of these publications are aqueous dispersions. However, depending on the use of these dispersions, an alcohol solvent may be used as a dispersion medium and high stability may be required. . When alcoholic dispersions having such high stability are required, it is not sufficient to simply apply the methods described in these publications.

JP 2009-173878 A JP 2009-242499 A International Publication No. 2009/119466

  Accordingly, an object of the present invention is to provide a highly stable PPS resin particle dispersion using an alcohol solvent as a dispersion medium and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have surprisingly been found to be extremely stable by mechanically dispersing fine PPS resin particles suspended in an alcohol solvent in the presence of a polymer surfactant. The present inventors have found that a dispersion having excellent properties can be obtained, and have reached the present invention.

That is, the present invention relates to a polyphenylene sulfide resin fine particle dispersion containing a polymer surfactant, polyphenylene sulfide resin fine particles and an alcohol solvent having 3 to 5 carbon atoms, and polyphenylene sulfide resin fine particles in the presence of the polymer surfactant. A polyphenylene sulfide resin fine particle dispersion , which is mechanically dispersed in a linear or branched alcohol solvent having a number of 3 to 5 , wherein the polymer surfactant is polyvinylpyrrolidone or polyethyleneimine a method for producing a resin particle dispersion States.

  By using the present invention, it is possible to easily produce an alcohol-based dispersion of PPS resin fine particles having extremely high stability, which has been difficult to obtain industrially, and can provide a wide range of industrially useful materials.

  Hereinafter, embodiments of the present invention will be described in detail.

[Raw PPS resin]
The PPS resin in the present invention is a chemical formula (1)

It is a homopolymer or copolymer having a repeating unit as shown in FIG. Ar is represented by chemical formulas (2) to (4).

(R ¹ and R ² are groups selected from hydrogen, alkyl groups, alkoxyl groups, and halogen groups). As long as this repetition the main constituent units, the formula (5) branching and coupling or and cross-linking is represented by such a chemical formula ^{(6) ~ (14) (} R 1, R 2 is hydrogen, an alkyl group, an alkoxyl group, A copolymer component represented by a halogen group) can be contained in a proportion of 30 mol% or less, preferably 10 mol% or less.

  PPS resin has the chemical formula (15) as the main structural unit of the polymer.

PPS containing 70 mol% or more, particularly 90 mol% or more of p-phenylene sulfide represented by the formula is particularly preferably used. As such PPS, what was synthesize | combined by the method normally used in N-alkylamide solvent from a dihalogen aromatic compound and an alkali metal sulfide can be used. For example, PPS having a relatively low molecular weight obtained by the production method described in Japanese Patent Publication No. 45-3368 and heating it in an oxygen atmosphere or adding a crosslinking agent such as a peroxide and heating the PPS There is a method for increasing the degree of polymerization. In addition, essentially linear and high molecular weight PPS is preferably used by the production method described in Japanese Patent Publication No. 52-12240.

  In order to produce high-quality PPS resin fine particles, a PPS resin having a content of inorganic ions as low as possible is particularly preferable. Therefore, the PPS resin is preferably used by removing by-products such as inorganic salts by a method such as washing. The cleaning method may be a commonly performed method. In addition, although the timing except a by-product may be performed after superposition | polymerization and may be performed at any of the process mentioned later, it is preferable to carry out before the below-mentioned melt | dissolution process. The PPS resin may be washed or treated with an aqueous metal solution to control crystal acceleration after removing by-products. For example, Japanese Patent Laid-Open No. 10-60113 discloses a method for producing a PPS resin in which the metal ion content is reduced by washing with an inorganic acid and / or organic acid having a pH of less than 7. Japanese Patent Laid-Open No. 2002-332351 discloses a method of treating with an aqueous solution containing a metal element of Group II of the periodic table. The PPS resin used in the present invention is a PPS resin from which by-products have been removed by the usual washing method after the above polymerization, a PPS resin that has been subjected to acid washing, and a PPS that has been treated with an aqueous solution containing a Group II metal element in the periodic table. Any of the resins can be used. In addition, what was synthesize | combined by the method as described in US Patent 5,869,599 specification and international publication 07/034800 can also be used.

[PPS resin fine particles]
The PPS resin fine particles used in the present invention are not limited as long as a stable dispersion can be obtained, but are preferably PPS resin fine particles having an average particle size of 1 μm or less, particularly an average particle size of 100 to 500 nm. The average particle diameter is a value measured by a laser diffraction / scattering type particle size distribution measuring apparatus described later.

[Production of fine PPS resin particles]
The PPS resin fine particles used in the present invention are preferably produced through the steps including the following steps (a) and (b).
(A) A process of heating a PPS resin in an organic solvent to form a PPS resin solution (dissolution process)
(B) A step of precipitating fine particles of PPS resin by flash cooling the solution (precipitation step).

[Dissolution process]
In the dissolving step, the PPS resin is dissolved by heating in an organic solvent. The form of the PPS resin used in the present invention is not particularly limited, and specific examples include powders, granules, pellets, fibers, films, molded products and the like. From the viewpoint of shortening the operability and time required for dissolution, powder, granules and pellets are desirable, and powdered PPS resin is particularly preferable. Here, in order to prevent corrosion of the apparatus due to coexisting inorganic ions, such as when the target PPS resin fine particles and dispersions thereof are used in water-soluble paints, etc., powders, granules, and pellets that do not contain inorganic ions The PPS resin is particularly preferred.

  Any organic solvent can be used as long as it is a solvent in which the PPS resin dissolves. Specifically, alkyl halides such as chloroform, aromatic halides such as o-dichlorobenzene and 1-chloronaphthalene, and N-alkylpyrrolidones such as N-methyl-2-pyrrolidinone (hereinafter abbreviated as NMP). N-alkylcaprolactams such as N-methyl-ε-caprolactam, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide (hereinafter abbreviated as DMF), Examples thereof include at least one solvent selected from polar solvents such as hexamethylphosphoric triamide, dimethyl sulfoxide (hereinafter abbreviated as DMSO), dimethyl sulfone, and tetramethylene sulfone. Among these, NMP is particularly preferable from the viewpoint of the solubility of the PPS resin.

  When the undissolved PPS resin or molten PPS resin is present at a predetermined temperature, the charged concentration of the PPS resin with respect to the organic solvent becomes a coarse particle or a lump after flash cooling and exists in the flash cooled liquid. These are not particularly limited because they can be easily removed by operations such as filtration and centrifugation. Usually, it is 0.1-10 mass parts of PPS resin with respect to 100 mass parts of organic solvents, Preferably it is 0.5-10 mass parts. If it is this range, it is applicable to industrial production. In the present invention, after the PPS resin is charged into the solvent and dissolved by heating, the PPS resin solution is flash-cooled in a solvent in which fine PPS resin particles are precipitated.

  In the dissolving step, a polymer surfactant or the like that can be uniformly dissolved in the solution can also be added. Polymer surfactants have a large number of non-ionic surfactants and anionic surfactants in the molecule compared to a structure having a pair of hydrophilic and lipophilic groups in the molecule. It is a surfactant having a complicated structure having a hydrophilic group and a lipophilic group and having a large molecular weight. Thus, general surfactants and polymer surfactants are greatly different both in structure and molecular weight. Among the polymer surfactants used in the present invention, a polymer surfactant having a number average molecular weight of 1000 or more (GPC measurement, styrene conversion) is preferable, and 5,000 or more is more preferable. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 1,000,000 or less.

  The polymer surfactant to be added may be any one that dissolves in the organic solvent to be used. Polymeric surfactants include polyvinylpyrrolidone (PVP), polypyrrole, polythiophene, (meth) acrylic acid copolymer, maleic acid copolymer, polystyrene sulfonate, vinylpyridine copolymer, polyethyleneimine, polyvinyl alcohol, Synthetic polymer surfactants such as polyvinyl ether and polyacrylamide, and semisynthetic polymer surfactants such as carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethyl sesulose, and hydroxypropylmethylcellulose are used.

  The amount of the polymer surfactant used is usually 0.01 to 5 times, preferably 0.01 to 1 times the amount of the charged PPS resin.

  The atmosphere of the tank of the dissolution process may be any of an air atmosphere, an inert gas atmosphere, or a solvent vapor atmosphere. In order to suppress the decomposition and deterioration of the PPS resin, and to proceed with the work more safely. It is preferable to reduce the oxygen gas concentration. Here, examples of the inert gas include nitrogen gas, carbon dioxide gas, helium gas, argon gas, etc. In consideration of economy and availability, nitrogen gas, argon gas, carbon dioxide gas is preferable, Particularly preferably, nitrogen gas or argon gas is used. In addition, as a method for setting the atmosphere in a solvent vapor, (1) a method in which the reaction tank is depressurized or vacuumed to remove air and then the temperature of the reaction tank is increased, and (2) while sucking air in the reaction tank, (3) A method of stopping the suction when the solvent vapor is filled while sucking the air in the reaction tank while the temperature is raised and the solvent vapor is filled, (3) 4) A method of blowing the same kind of vapor as the solvent into the reaction vessel while sucking the air in the reaction vessel, or a combination of these methods, and thereby making the inside of the dissolution vessel a vaporized solvent vapor atmosphere. Can do. In addition, when employ | adopting the method of (2)-(4), it is desirable to grasp | ascertain the quantity of the solvent in a dissolution tank.

  The dissolution method is not particularly limited, but a PPS resin and a solvent are placed in a predetermined container and heated while stirring. In order to produce fine PPS resin particles having a uniform particle size, a method in which the PPS resin is completely dissolved in a solvent and then flash-cooled and precipitated is preferable. However, undissolved PPS resin or molten PPS resin may be present. . Although the PPS resin can be dissolved at the boiling point of the solvent and precipitated from the dilute solution, the solubility of the PPS resin in the organic solvent is small, so that the boiling point of the solvent is higher than the boiling point of the solvent and less than the decomposition point of the PPS resin. A method of dissolving by heating is preferred.

  The dissolution temperature varies depending on the type of solvent used and the concentration of the PPS resin, but is usually 200 ° C. to 400 ° C., preferably 220 ° C. to 320 ° C. When the temperature is high, the PPS resin is decomposed. Moreover, if it is less than 200 degreeC, in order to melt | dissolve PPS resin, a large amount of solvent will be used.

  The dissolution time varies depending on the type of solvent, the concentration of the PPS resin, and the dissolution temperature, but is usually 10 minutes to 10 hours, preferably 20 minutes to 8 hours, more preferably 30 minutes to 5 hours.

  By the above operation, the PPS resin can be dissolved. Here, when dissolving in a pressure vessel such as an autoclave, there may be cases where it is not possible to directly confirm the presence or absence of undissolved resin or the presence of a resin that is in a molten state without being dissolved due to structural reasons. If the fine particles deposited in the precipitation step are different from the PPS resin before dissolution in shape and particle size, the result is determined by the dissolution / precipitation of the present invention. The shape and particle size change due to this dissolution / precipitation is judged from the change in average particle size using a particle size distribution meter and the shape change by SEM.

[Precipitation process]
The PPS resin solution dissolved in the dissolution step is flash-cooled in a solvent for precipitating PPS resin fine particles to precipitate the PPS resin fine particles. In the present invention, flash cooling refers to the above-mentioned solution under heating / pressurization not higher than the boiling point of the organic solvent used in the dissolving step (may be under cooling) / below the pressure under pressure (may be under reduced pressure). It refers to a method in which the liquid is jetted through another nozzle (hereinafter sometimes referred to as a receiving tank) and transferred, and then rapidly cooled using the cooling effect due to the pressure difference or the cooling effect due to latent heat.

  Specifically, it is preferable that the PPS resin solution is flash-cooled from a container held under heating and pressurization into a receiving tank under atmospheric pressure (or under reduced pressure). For example, in the melting step, when the melting is performed in a pressure-resistant container such as an autoclave, the inside of the container is pressurized by a self-made pressure by heating. By releasing the pressure from this state and releasing it into a receiving tank under atmospheric pressure, it can be carried out more easily. In addition, when flash-cooling in a solvent for precipitating PPS resin fine particles, it is desirable to rapidly cool in order to obtain finer PPS resin fine particles, and both the cooling effect due to the pressure difference and the cooling effect due to latent heat are effective. More preferred is direct flash cooling into the resulting solvent.

  Although there is no restriction | limiting in particular as a solvent which precipitates PPS resin microparticles | fine-particles, From the viewpoint of disperse | distributing uniformly in a solvent, it is preferable that it is a solvent mixed uniformly with the organic solvent used at a melt | dissolution process. Here, uniform mixing means that when two or more solvents are mixed, the interface does not appear even if the mixture is allowed to stand for one day, and is mixed uniformly. For example, with respect to water, NMP, DMF, acetone, DMSO, tetrahydrofuran, methanol, ethanol and the like can be mentioned as a solvent in which they are uniformly mixed.

  Specifically, it can also be used as a solvent for precipitating a solvent that dissolves the PPS resin, but it is uniform with the solvent used in the dissolving step from the point that fine PPS resin fine particles are obtained and the particle size is easily uniform. It is preferable to mix and to contain the poor solvent of PPS resin. When NMP is selected as the solvent for the dissolution step, NMP, alcohols, acetones, water, and the like can be used, and the solvent for precipitation can be selected according to the purpose. In particular, it is preferable to use water because fine PPS resin fine particles having a uniform particle diameter can be easily obtained. The solvent for precipitating the PPS resin fine particles may be a single solvent or a mixture of two or more solvents as long as it is uniformly mixed with the organic solvent used in the dissolving step. In particular, it is preferable to use a mixed solvent containing water because fine particles having a uniform particle diameter can be easily obtained. Of these, a mixed solvent of water and NMP is preferable.

  Although the usage-amount of the solvent which deposits PPS resin microparticles | fine-particles is not specifically limited, The range of 100-0.1 mass part can be illustrated with respect to 1 mass part of solvent of a melt | dissolution process, Preferably it is 50-0.1 mass. Parts, more preferably 15 to 0.1 parts by mass.

  A polymer surfactant may be added in a solvent for precipitating the PPS resin fine particles. As the polymer surfactant to be added, the polymer surfactants mentioned in the dissolution step can be used, but a new polymer surfactant may be used. The amount used varies depending on the type and purpose of use of the polymeric surfactant, but is preferably 2 times or less, more preferably 0.01 to 1 times the mass of the PPS resin fine particles.

  The flash cooling method is not particularly limited, but is usually a method of flash-cooling a solution at a temperature of 200 ° C. to 400 ° C., preferably 220 ° C. to 320 ° C. below the pressure under pressure, or in a single stage in a container under reduced pressure, Alternatively, a method of flash cooling in multiple stages in a container having a lower pressure than the inside of the tank containing the dissolved solution can be employed. In order to obtain fine PPS resin fine particles, it is preferable that the pressure difference is large and the temperature difference is large. Specifically, for example, in the melting step, when the melting is performed in a pressure-resistant container such as an autoclave, the inside of the container is pressurized by a self-made pressure by heating. The solution in a pressurized state is flushed in an atmospheric pressure receiving tank containing a solvent for precipitating PPS resin fine particles, or is flushed in a receiving tank under reduced pressure. The pressure (gauge pressure) of the solution for flash cooling is preferably 0.2 to 4 MPa. From this environment, it is preferred to flash cool it, preferably into a receiving vessel under atmospheric pressure.

  In the case of flash cooling in a solvent for precipitating PPS resin fine particles, the boiling point of the organic solvent used in the dissolution process is obtained by cooling the receiving tank with a refrigerant or ice water and cooling the solvent for precipitating the PPS resin fine particles in the receiving tank in advance. Since it can be cooled at once and fine PPS resin fine particles are obtained, it is preferable. By this flash cooling, the PPS resin fine particles are precipitated from the solution of the PPS resin, and a liquid in which the PPS resin fine particles are dispersed or suspended is obtained. The cooling temperature of the receiving tank varies depending on the solvent for precipitating the PPS resin fine particles to be put in the receiving tank, but the temperature at which the solvent for precipitating the PPS resin fine particles does not solidify is 15 to 15 ° C. -40 degreeC is preferable and 0-15 degreeC is more preferable.

  The method of flash cooling into the solvent for precipitating the PPS resin fine particles is a method in which the outlet of the connecting pipe from the dissolution tank is placed in the solvent for precipitating the PPS resin fine particles in the receiving tank, and the method of flash cooling is a finer dispersion of the fine PPS resin fine particles. Alternatively, a suspension is obtained, which is preferable.

  The average particle diameter of the primary particles of the PPS resin fine particles thus obtained is 1 μm or less, and in many cases, 300 nm or less. The average particle size of the primary particles is an average value obtained by measuring arbitrary 100 particle sizes of PPS resin fine particles observed with a scanning electron microscope (hereinafter referred to as SEM).

[Filtration / isolation process]
In order to replace the flash solution with an alcohol solvent, solid-liquid separation is once performed to isolate the PPS resin fine particles. As a method for isolating PPS resin fine particles, it can be performed by a conventionally known solid-liquid separation method such as filtration, centrifugal separation, centrifugal filtration, etc., but PPS resin fine particles of less than 1 μm are efficiently isolated by solid-liquid separation operation. In order to achieve this, it is desirable to increase the particle size by aggregation and then perform solid-liquid separation operations such as filtration and centrifugation. As a method of increasing the particle size by agglomeration, a natural agglomeration method that agglomerates with time, an agglomeration method by heating, an agglomeration method using an aggregating agent such as salting out, and the like can be used. Thus, an aggregate having a large particle size suitable for an industrial solid-liquid separation method can be obtained. The average particle size of the aggregates at this time is preferably 5 to 50 μm (particle size according to the measurement method described later).

  Specifically, in the case of the natural agglomeration method, the agglomeration time can be shortened by allowing the flash solution to stand at a temperature of 50 ° C. to 100 ° C. by allowing it to stand for one day or more, and after allowing it to stand for a day. In salting out, an aggregate having a large particle size can be obtained by adding an inorganic salt in an amount of 0.1 to 1000% by mass, preferably about 0.5 to 500% by mass with respect to 1 part by mass of PPS resin fine particles. Specifically, a method such as adding an inorganic salt directly to the dispersion or suspension, or adding a 0.1 to 20% by mass solution of the inorganic salt can be used. Inorganic salts 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, magnesium citrate, citric acid Examples thereof include inorganic salts such as calcium acid. As a solvent for dissolving the inorganic salt, water is preferable. Alternatively, the inorganic salt can be dissolved in a solvent for precipitating the fine PPS resin particles in the receiving tank when the inorganic salt is flash cooled. The solvent for precipitating the PPS resin fine particles at this time is preferably water. The amount of the inorganic salt to be added is preferably 0.1% by mass or more with respect to 1 part by mass of the PPS resin fine particles and not more than the saturated dissolution amount in the solvent in which the PPS resin fine particles are precipitated. The PPS resin fine particles obtained by flash cooling as in the present invention can be easily separated into solid and liquid by agglomeration by such a method. Moreover, even if it aggregates by such a method, the PPS resin microparticles | fine-particles which are very easy to redisperse are obtained.

  Examples of the solid-liquid separation method include methods such as filtration and centrifugation. In the case of filtration or centrifugation, a membrane filter (filtration) or a filter cloth (filtration, centrifugation) can be used.

The opening of the filter is appropriately determined according to the particle size of the PPS resin fine particles to be obtained. In the case of a membrane filter, it is usually about 0.1 to 50 μm. In the case of a filter cloth, the air permeability is 5 cm ³ / cm. Those of ² · sec at 124.5 Pa or less can be used. In order to replace the solvent in the wet cake after the solid-liquid separation with the dispersion medium used in the dispersion step, the wet cake may be reslurried with the dispersion medium used in the dispersion step, or washed by washing with the dispersion medium used in the dispersion step.

[Dispersion process]
The fine PPS resin fine particle dispersion can be obtained by redispersing the PPS resin fine particles obtained in the filtration / isolation step by mechanical dispersion. The PPS resin fine particles contain a solvent or a dispersion medium in order to obtain a PPS resin fine particle dispersion in which the particles are stably and finely dispersed by dispersion because the PPS resin fine particles are difficult to be dispersed in the filtration / isolation process. It is necessary to keep it in a state. The PPS resin fine particles used in the dispersion step are preferably in a state containing 50% by mass or more of a solvent or dispersion medium.

  A polymer surfactant and a dispersion medium are added to the fine PPS resin particles obtained by solid-liquid separation operation or the like, and the resultant is subjected to a dispersion step.

  The medium that can be a new dispersion medium is n-propanol, isopropanol, n-butanol, isobutanol, 2-butyl alcohol, tert-butyl alcohol, n-pentyl alcohol, 2-pentyl alcohol, 3-pentyl alcohol, 2- Examples thereof include at least one solvent selected from linear or branched alcohol solvents having 3 to 5 carbon atoms, such as methyl-1-butyl alcohol, 3-methyl-1-butyl alcohol, and 2-methyl-2-butyl alcohol. N-propyl alcohol and isopropyl alcohol are preferred.

  In order to suppress aggregation of the PPS resin fine particles generated by mechanical dispersion and improve dispersibility in the dispersion medium, a polymer surfactant is added. The addition timing of the polymer surfactant may be before or after mechanical dispersion, but to prevent aggregation of fine particles during mechanical dispersion, addition before dispersion, or addition method using both addition before dispersion and addition during dispersion Is preferred.

  The number average molecular weight of the polymer surfactant is preferably 1,000 or more, and more preferably 5,000 or more. Although there is no restriction | limiting in particular as an upper limit, It is preferable that it is 1,000,000 or less. As the polymer surfactant, the polymer surfactants mentioned in the dissolution step can be used, but a new polymer surfactant may be used.

  The addition amount of these polymer surfactants is in the range of 0.01 to 100 parts by mass, preferably in the range of 0.5 to 100 parts by mass, and more preferably with respect to 100 parts by mass of the PPS resin fine particles. 1 to 100 parts by mass. By using the amount of the polymer surfactant in this range, the PPS resin fine particles obtained by mechanical dispersion can be dispersed uniformly in the dispersion medium very efficiently. The content of PPS resin fine particles in the PPS resin fine particle dispersion or suspension to be subjected to mechanical dispersion is preferably in the range of 1 to 50 parts by mass, particularly 1 to 30 parts by mass with respect to 100 parts by mass of the dispersion medium. It is preferable that

  The PPS resin fine particles obtained in the filtration / isolation step are preferably subjected to mechanical dispersion of the PPS resin fine particle suspension until an average particle size in a measurement method described later becomes 1 μm or less. It is more preferable to perform mechanical dispersion until the average particle size after coarse particle separation becomes 500 nm or less. Although there is no restriction | limiting in a minimum, it is preferable that an average particle diameter is 100 nm or more from the point of aggregation suppression. Examples of the mechanical dispersion device include a commercially available mechanical dispersion device. In particular, ultrasonic dispersing devices, ball mill devices, bead mill devices, sand mill devices, colloid mill devices are suitable as mechanical dispersion devices for efficiently dispersing PPS resin fine particles and preparing dispersions of PPS resin fine particles having a small particle size. Wet atomizers (for example, manufactured by Sugino Machine, Optimizer) are preferable, and among these, an apparatus selected from an ultrasonic dispersing device, a bead mill device, a colloid mill device, and a wet atomizer is preferable. The average particle size of the resulting fine particles tends to decrease as the dispersion force during mechanical dispersion generally increases and the dispersion time increases. However, if these are excessive, reaggregation tends to occur. It is controlled in the range. For example, the bead mill can be controlled by selecting the bead diameter and the bead amount and adjusting the peripheral speed, and the ultrasonic dispersing device can be controlled by selecting the ultrasonic frequency and adjusting the ultrasonic output.

  The PPS resin fine particle dispersion may also contain coarse particles and precipitates in some cases. In that case, coarse particles or precipitates may be separated from the dispersed portion. When only the dispersion liquid is obtained, the coarse particles and precipitates may be separated from the dispersion portion. For that purpose, decantation, filtration, centrifugation, etc. may be performed to remove the coarse particles and precipitate portions.

  As described above, a very stable dispersion of PPS resin fine particles in which the PPS resin fine particles are finely dispersed can be obtained.

  Such a fine PPS resin fine particle dispersion does not settle even when allowed to stand at room temperature (25 ° C.) for 24 hours, and is a particularly useful additive in the fields of paint, adhesion, and polymer compounds. Can be used as

[Measurement of average particle size]
The average particle size of the PPS resin fine particles is Nikkiso's laser diffraction / scattering type particle size distribution measuring device MT3300EXII, and polyoxyethylene cumylphenyl ether (trade name: Nonal 912A, manufactured by Toho Chemical Industries, hereinafter referred to as Nonal 912A) as a dispersion medium. It measured using 0.5 mass% aqueous solution. Specifically, the cumulative curve is obtained by setting the total volume of fine particles obtained by analyzing the scattered light of the laser by the microtrack method to 100%, and the particle diameter (median diameter: d50) at which the cumulative curve becomes 50% is obtained. The average particle size of the fine particles was used.

[Measurement of average primary particle size]
In the present invention, the average primary particle size is selected by arbitrarily selecting 100 particles from an image obtained with a scanning electron microscope JEOL JMS-6700F manufactured by JEOL, and the particle size is measured using the maximum length as the particle size. The average value was taken as the average primary particle size.

[Ultrasonic dispersion]
Ultrasonic dispersion is an ultrasonic homogenizer manufactured by Nippon Seiki, US-300T (ultrasonic oscillator: rated output 300 W, oscillation frequency 19.5 KHz ± 1 KHz (automatic frequency tracking type), ultrasonic transducer: φ26 mm PZT (bolt clamped strain type) The ultrasonic oscillation chip was adjusted to a predetermined output using a vibrating element) and contacted in the PPS resin fine particle suspension.

Production Example 1
[Dissolution process]
A valve was opened and closed in a 9.8 L autoclave (dissolution tank), and a connecting pipe was mounted so that the end of the pipe was positioned in the tank. Further, as a receiving tank for flash cooling, 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 dissolution tank was installed in the tank. PPS resin powder (210 g) and NMP (6,790 g) were placed in a dissolution tank, and the valve of the internal connection pipe was sealed, followed by nitrogen replacement. The temperature was raised to 280 ° C. while stirring, and the mixture was stirred for 1 hour. The internal pressure (gauge pressure) at this time was 0.4 MPa.

[Precipitation process]
2,800 g of water was put in the receiving tank, and the tip of the connecting pipe installed in the receiving tank was put in water. The receiving tank was ice-cooled and nitrogen gas was vented. At this time, the temperature of the receiving tank was 5 ° C. The valve of the connecting pipe of the dissolution tank was opened, and the dissolution liquid was flash-cooled in the receiving tank water. The average particle size of the PPS resin fine particles in the flash solution was 12 μm. The flash solution was added to 2,800 g of a 0.38 wt% magnesium acetate aqueous solution, stirred for 1 hour, and allowed to stand for 5 hours. The average particle size after standing was 35 μm. The salting-out solution was subjected to solid-liquid separation using a centrifugal dehydrator, and the solid content was collected by filtration. The solid content was suspended in 1,800 g of ion-exchanged water, and then filtered with a centrifugal dehydrator. The same operation was performed twice to obtain hydrous PPS resin fine particles (919 g, PPS solid content 185 g). The average primary particle size was 115 nm.

Production Example 2
A suspension of PPS particles was prepared by adding 270 g of isopropyl alcohol to 149.3 g of water-containing PPS resin fine particles (PPS solid content 30.0 g), and then predispersed with a homomixer. The suspension was separated into solid and liquid by centrifugal filtration. This operation was further carried out twice to obtain 84.2 g of isopropyl alcohol-containing PPS resin fine particles (PPS solid content 29.2 g).

Production Example 3
270 g of n-propyl alcohol was added to 125 g of water-containing PPS resin fine particles (PPS solid content 25.1 g) to prepare a PPS particle suspension, and then predispersed with a homomixer. The suspension was separated into solid and liquid by centrifugal filtration. This operation was further performed twice to obtain 64.2 g of n-propyl alcohol PPS resin fine particles (PPS solid content 23.2 g).

Production Example 4
270 g of n-butyl alcohol was added to 150 g of water-containing PPS resin fine particles (PPS solid content: 30.2 g) to prepare a PPS particle suspension, which was then predispersed with a homomixer. The suspension was separated into solid and liquid by centrifugal filtration. This operation was further carried out twice to obtain 77.7 g of n-butyl alcohol PPS resin fine particles (PPS solid content 28.1 g).

Example 1
10 g of 10% isopropyl alcohol solution of PVP (manufactured by Tokyo Chemical Industry Co., Ltd., polyvinylpyrrolidone K30, molecular weight 40,000) and 76.2 g of isopropyl alcohol were added to 13.8 g of the isopropyl alcohol PPS resin fine particles of Production Example 2 at 1400 rpm. Stir for 10 minutes. The suspension was dispersed using ultrasonic waves (output 120 W) until the average particle size of the PPS resin fine particles reached 468 nm. The average particle size after removing coarse particles by centrifugation was 311 nm. When the dispersion was allowed to stand at room temperature for 48 hours, it did not aggregate and was stable.

Example 2
10 g of a 10% isopropyl alcohol solution of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., Epomin P-1000, molecular weight 70,000) and 75.8 g of isopropyl alcohol were added to 14.2 g of the isopropyl alcohol-containing PPS resin fine particles of Production Example 2. And stirred at 1400 rpm for 10 minutes. Using ultrasonic waves (output 120 W), the PPS resin fine particles in the suspension were dispersed until the average particle size became 604 nm. The average particle size after removing coarse particles by centrifugation was 372 nm. When the dispersion was allowed to stand at room temperature for 48 hours, it did not aggregate and was stable.

Example 3
10 g of a 10% n-propyl alcohol solution of PVP (manufactured by Tokyo Chemical Industry Co., Ltd., polyvinylpyrrolidone K30, molecular weight 40,000) and 16.0 g of n-propyl alcohol 76. 1 g was added and stirred at 1400 rpm for 10 minutes. Using ultrasonic waves (output 120 W), the PPS resin fine particles in the suspension were dispersed until the average particle size became 524 nm. The average particle size after removing coarse particles by centrifugation was 291 nm. When the dispersion was allowed to stand at room temperature for 48 hours, it did not aggregate and was stable.

Example 4
10 g of a 10% n-butyl alcohol solution of PVP (manufactured by Tokyo Chemical Industry Co., Ltd., polyvinylpyrrolidone K30, molecular weight 40,000) and 16.2 g of n-butanol PPS resin fine particles of Production Example 4 and 76.2 g of n-butyl alcohol And stirred at 1400 rpm for 10 minutes. Using an ultrasonic wave (output 120 W), the PPS resin fine particles in the suspension were dispersed until the average particle size became 587 nm. The average particle size after removing coarse particles by centrifugation was 322 nm. When the dispersion was allowed to stand at room temperature for 48 hours, it did not aggregate and was stable.

Comparative Example 1
The same procedure as in Example 1 was carried out except that PVP in Example 1 was replaced with lauryl alcohol-EO (3) -H (Kao Corporation, Emulgen 103, molecular weight 318). The average particle size of the obtained dispersion was 1.4 μm. When the dispersion was allowed to stand for 48 hours, the dispersion medium and the solid content were separated.

Claims (9)

A polyphenylene sulfide resin fine particle dispersion comprising a polymer surfactant having a number average molecular weight of 1,000 or more and 1,000,000 or less, polyphenylene sulfide resin fine particles and an alcohol solvent having 3 to 5 carbon atoms , wherein the polymer interface A polyphenylene sulfide resin fine particle dispersion in which the activator is polyvinylpyrrolidone or polyethyleneimine. The polyphenylene sulfide resin fine particle dispersion according to claim 1, wherein the polyphenylene sulfide resin has a repeating unit represented by the chemical formula (1) as a main constituent unit.

Here, Ar is (2) to (4), and R ¹ , R ² Is a group selected from hydrogen, an alkyl group, an alkoxyl group, and a halogen group.

The polyphenylene sulfide resin fine particle dispersion according to claim 1, wherein the alcohol solvent is a linear or branched alcohol. The polyphenylene sulfide resin fine particle dispersion according to claim 3, wherein the alcohol solvent is isopropyl alcohol or n-propyl alcohol. Polyphenylene sulfide resin fine particles characterized by mechanically dispersing polyphenylene sulfide resin fine particles in an alcohol solvent having 3 to 5 carbon atoms in the presence of a polymer surfactant having a number average molecular weight of 1,000 or more and 1,000,000 or less. A method for producing a dispersion , wherein the polymer surfactant is polyvinyl pyrrolidone or polyethyleneimine . The method for producing a polyphenylene sulfide resin fine particle dispersion according to claim 5, wherein the polyphenylene sulfide resin has a repeating unit represented by the chemical formula (1) as a main structural unit.

Here, Ar is (2) to (4), and R ¹ , R ² Is a group selected from hydrogen, an alkyl group, an alkoxyl group, and a halogen group.

The method for producing a polyphenylene sulfide resin fine particle dispersion according to any one of claims 5 to 6, wherein the alcohol solvent is a linear or branched alcohol. The method for producing a polyphenylene sulfide resin fine particle dispersion according to claim 7, wherein the alcohol solvent is isopropyl alcohol or n-propyl alcohol. The polyphenylene sulfide resin fine particle dispersion according to any one of claims 5 to 8, wherein the mechanical dispersion is performed by any one of an ultrasonic dispersion device, a bead mill device, a colloid mill device, and a wet atomization device. Production method.