JP2007308612A - Polyphenylene sulfide resin, manufacturing method thereof, and molded article therefrom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyphenylene sulfide resin which has little evolved amount of the volatile components at the time of melt flowing and melting. <P>SOLUTION: The polyphenylene sulfide resin comprises a thermal-oxidation treated polyphenylene sulfide resin, has an evolved gas amount volatilized of 0.3% by weight or less at the time of heat melting at 320°C for 2 hours under vacuum, and has a residue of 4.0% by weight or less at the time of filtering under heat and pressure with a PTFE membrane filter having a pore size of 1 μm after dissolved in a twenty-fold weight of 1-chloronaphthalene at 250°C for 5 minutes, and also has a melt flow rate (on the basis of ASTM D-1238-70, measured at a temperature of 315.5°C and under a load of 5,000 g) of more than 500 g/10 min. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polyphenylene sulfide resin that is excellent in melt fluidity and generates a small amount of volatile components at the time of melting, a method for producing the same, and an injection molded product.

  Polyphenylene sulfide (hereinafter abbreviated as PPS) resin has excellent properties as engineering plastics such as excellent heat resistance, barrier properties, chemical resistance, electrical insulation properties, and heat and humidity resistance, mainly for injection molding and extrusion molding. It is used for various electrical / electronic parts, machine parts, automobile parts, films, fibers and the like.

  However, since the melting point of PPS resin is high, the melt processing temperature is high, so that volatile components are likely to be generated. In particular, when used for injection molding, molding failure may occur due to mold contamination or mold vent clogging. Therefore, reduction of volatile components is strongly desired. Such volatile components can be reduced by heat-treating the PPS resin at a temperature below the melting point, but excessive heat-treatment causes problems such as an excessive increase in melt viscosity and deterioration of moldability due to the formation of a gelled product. The present invention has found that the volatile component is greatly reduced by performing thermal oxidation treatment under specific conditions without significantly increasing the melt viscosity.

  Thermal oxidation treatment of PPS resin has been performed for a long time. For example, Patent Document 1 discloses that the polymer viscosity is in the range of 5000 to 16000 poise (500 to 1600 Pa · s) (310 ° C., shear rate of 200 / sec), and the non-Newtonian coefficient n is in the range of 1.5 to 2.1. Thus, an extruded product obtained by curing the PPS resin and melting and extruding the PPS resin is disclosed. However, when converted into a melt flow rate, 5000 poise is less than 100 g / 10 min. Since the PPS resin has a melt viscosity that is too high, the fluidity during injection molding is significantly deteriorated. Not suitable for injection molding. The PPS resin disclosed in the patent has a relatively high degree of thermal oxidation treatment, and if the degree of thermal oxidation treatment is too large, the gas reduction effect is saturated, but the melt fluidity is lowered.

  Patent Document 2 discloses a method of thermally oxidizing a granular PPS resin having a weight average molecular weight of 30,000 or more and an average particle diameter of 50 μm or less. However, as described in Patent Document 2, in order to obtain a PPS resin having a weight average molecular weight of 30,000 or more and an average particle diameter of 50 μm or less, a special polymerization apparatus or pulverization is required, and costs are increased. This is not a general method. Further, such fine PPS particles are inferior in biting to the extruder at the time of melt kneading and are economically disadvantageous because the amount of melt kneading extrusion per unit time is reduced.

Although Patent Document 3 discloses a method of curing a PPS resin in a low oxygen atmosphere, it can achieve both excellent melt fluidity and low volatile component by performing thermal oxidation treatment under specific conditions. There is no mention of anything.
Japanese Patent Laid-Open No. 63-207827 (Claims) JP-A-6-248078 (Claims) JP-A-1-121327 (Claims)

  An object of the present invention is to obtain a polyphenylene sulfide resin that is excellent in melt fluidity and generates a small amount of volatile components at the time of melting, a method for producing the same, and an injection molded article.

  Accordingly, as a result of studying the present inventors to solve the above-mentioned problems, the amount of volatile components generated during melting is reduced more than expected by subjecting PPS having a relatively low viscosity to a relatively mild thermal oxidation treatment. In addition, the inventors have found that an injection-molded article made of a polyphenylene sulfide resin, a process for producing the same, and a polyoxidized sulfide resin that has been thermally oxidized can be obtained.

That is, the present invention
1. It is made of polyphenylene sulfide resin that has been subjected to thermal oxidation treatment. The amount of gas that evaporates when heated and melted at 320 ° C for 2 hours under vacuum is 0.3% by weight or less, and at 250 ° C for 5 minutes, 20 times. The amount of residue when dissolved by weight of 1-chloronaphthalene and filtered under pressure with a PTFE membrane filter having a pore size of 1 μm is 4.0% by weight or less, and the melt flow rate (according to ASTM D-1238-70) (Measured at a temperature of 315.5 ° C. and a load of 5000 g.) A polyphenylene sulfide resin exceeding 500 g / 10 min.
2. The polyphenylene sulfide resin according to the above item 1, comprising a polyphenylene sulfide resin that has been subjected to thermal oxidation treatment, wherein the average particle size is in a range exceeding 50 μm;
3. 3. The polyphenylene sulfide resin according to the above item 1 or 2, wherein the polyphenylene sulfide resin is a polyphenylene sulfide resin recovered by a flash method.
4). The method for producing a polyphenylene sulfide resin according to any one of the above items 1 to 3, wherein the thermal oxidation treatment temperature (Tc) has the following relationship with the melting point (Tm) of the polyphenylene sulfide resin before the thermal oxidation treatment: ,
Tm (° C.) − 130 ° C. <Tc <Tm (° C.) − 70 ° C.
5). The method for producing a polyphenylene sulfide resin according to the above item 4, wherein the polyphenylene sulfide resin is a polyphenylene sulfide resin recovered by a flash method,
6). A molded article formed by injection molding the polyphenylene sulfide resin according to any one of the above items 1 to 3 or the polyphenylene sulfide resin obtained by the production method according to any one of the above 4 to 5.
It is composed of.

  According to the present invention, the amount of volatile components at the time of melting is reduced more than expected and the melt fluidity is excellent, and the injection molding comprising a polyphenylene sulfide resin, a method for producing the same, and a thermally oxidized polyphenylene sulfide resin The body is obtained.

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

(1) PPS resin The PPS resin in the present invention is a polymer having a repeating unit represented by the following structural formula (I),

From the viewpoint of heat resistance, a polymer containing 70 mol% or more, more preferably 90 mol% or more of a polymer containing a repeating unit represented by the above structural formula is preferred. Moreover, about 30 mol% or less of the repeating unit of the PPS resin may be composed of a repeating unit having the following structure.

  The PPS resin of the present invention is characterized by being oxidized and crosslinked by thermal oxidation treatment. The melt flow rate after thermal oxidation treatment (according to ASTM D-1238-70. Measured at a temperature of 315.5 ° C. and a load of 5000 g) needs to be in a range exceeding 500 g / 10 minutes. When the melt flow rate after the thermal oxidation treatment is 500 g / 10 min or less, the melt fluidity of the PPS resin composition is remarkably deteriorated particularly when the filler is used in a highly filled state. Although there is no restriction | limiting in particular about the upper limit of the melt viscosity after a thermal oxidation process, From a viewpoint of obtaining resin (composition) which has the intensity | strength which can be used practically, it is 1 Pa * s (300 degreeC, shear rate 1000 / sec) or more. Is preferred.

  In the PPS resin of the present invention, the amount of gas that volatilizes when heated and melted at 320 ° C. for 2 hours under vacuum needs to be 0.3% by weight or less, preferably 0.28% by weight or less, more preferably It is desirable that it is 0.22% by weight or less. If the amount of gas generated after the thermal oxidation treatment exceeds 0.3% by weight, volatile components adhering to the mold and the mold vent portion are increased, and transfer defects and gas burns are liable to occur. The lower limit of the gas generation amount after the thermal oxidation treatment is not particularly limited, but is 0.03% or more, preferably 0.05% or more. If the lower limit of the gas generation amount is less than 0.03%, the volatile components adhering to the mold and the mold vent portion will be reduced, but the time for thermal oxidation treatment will be increased until the gas generation amount is reduced, which is economical. It is disadvantageous. In addition, due to the prolonged thermal oxidation treatment, gelled products are easily generated, which may be a cause of molding defects.

  The gas generation amount means the amount of an adhesive component in which the gas that volatilizes when the PPS resin is heated and melted under vacuum is cooled and liquefied or solidified, and is a glass in which the PPS resin is vacuum-sealed. It is measured by heating the ampule in a tubular furnace. As the shape of the glass ampule, the abdomen is 100 mm × 25 mm, the neck is 255 mm × 12 mm, and the wall thickness is 1 mm. As a specific measurement method, only the barrel of a glass ampoule in which PPS resin is vacuum-sealed is inserted into a 320 ° C. tubular furnace and heated for 2 hours, so that it becomes volatile at the neck of the ampule not heated by the tubular furnace. The gas is cooled and adheres. After the neck is cut out and weighed, the adhering gas is dissolved in chloroform and removed. The neck is then dried and weighed again. The amount of gas generated is determined from the difference in weight between the neck of the ampoule before and after removing the gas.

  The PPS resin of the present invention is dissolved in 20-fold weight of 1-chloronaphthalene at 250 ° C. for 5 minutes, and the residual amount when heated and filtered through a PTFE membrane filter having a pore size of 1 μm is 4.0% by weight or less. Preferably, it is 3.5% by weight or less, more preferably 3.0% by weight or less. When the residual amount exceeds 4.0% by weight, it means that the thermal oxidation crosslinking of PPS proceeds excessively and the gelled product in the resin increases. Even if PPS thermal oxidation cross-linking is advanced excessively, the effect of reducing the volatile matter is small, and on the other hand, the melt fluidity is lowered and the molding failure due to the gelled product is not preferable. The lower limit of the residual amount is not particularly limited, but is 1.5% or more, preferably 1.7% or more. If the residual amount is less than 1.5%, the degree of thermal oxidation cross-linking is too slight, so that the volatile components at the time of melting do not decrease so much and the volatile matter reducing effect may be small.

  The residual amount is measured using a SUS test tube equipped with a high-temperature filtration device, a pneumatic cap, and a collecting funnel using a PPS resin formed into a press film of about 80 μm thickness as a sample. Specifically, a membrane filter having a pore size of 1 μm is first set in a SUS test tube, and then PPS resin formed into a press film to a thickness of about 80 μm and 1-chloronaphthalene having a weight of 20 times are weighed and sealed. This is set in a high-temperature filter at 250 ° C. and shaken for 5 minutes. Next, a syringe containing air is connected to the pneumatic cap, the piston of the syringe is pushed out, and hot filtration by pneumatic pressure is performed. As a specific quantification method of the remaining amount, it is determined from the weight difference between the membrane filter before filtration and the membrane filter vacuum-dried at 150 ° C. for 1 hour after filtration.

    The average particle size of the PPS resin particles of the present invention is preferably in the range exceeding 50 μm, more preferably in the range of 60 μm or more. In addition, an average particle diameter here shows the particle diameter (D50) corresponding to 50% of the integrated distribution obtained by measuring with a sieving method. The standard sieve mesh used in the sieving method is a combination of 20 mesh, 32 mesh, 60 mesh, 200 mesh, 330 mesh if the particle size is relatively fine, and 4 mesh, 7 if the particle size is relatively coarse. The mesh, 14 mesh, 20 mesh, 32 mesh, and 60 mesh are combined, put into the standard sieve at the top of the shaker with the standard sieve set, then cover and shake for 30 minutes. The amount of the remaining sample is weighed, the openings (μm) corresponding to each mesh and the integrated weight are plotted, and the particle diameter (D50) corresponding to 50% of the integrated distribution is taken as the average particle diameter.

  In order to obtain a PPS resin having an average particle size that is too small, as described in the prior art, a special polymerization apparatus or pulverization is required, which is expensive and is not a preferable method. Further, such fine PPS particles are inferior in biting to the extruder during melt-kneading, and are disadvantageous economically because the amount of melt-kneaded extrusion per unit time is reduced. The upper limit of the average particle size is not particularly limited, but is preferably 750 μm or less, and more preferably 600 μm or less. When trying to obtain PPS having a particle size of 750 μm or more by a usual method, it is necessary to slowly cool the polymerization system after the completion of the polymerization process, which means that the polymerization time is extended, and if possible, it is cooled rapidly. It is economically advantageous to collect by the flash method described later.

In the present invention, the thermal oxidation treatment temperature (Tc) is preferably in the relationship of the following formula 1 with the melting point (Tm) of the polyphenylene sulfide resin before the thermal oxidation treatment,
Tm (° C.) − 130 ° C. <Tc <Tm (° C.) − 70 ° C. Formula 1
More preferably, the relationship is represented by the following formula 2.
Tm (° C.) − 120 ° C. <Tc <Tm (° C.) − 80 ° C. Formula 2

  When the thermal oxidation treatment is performed at a temperature of Tc (Tm (° C.) − 70 ° C.) or higher, the thermal oxidation treatment proceeds rapidly, and thus control is difficult, which is not preferable. On the other hand, a temperature of Tc (Tm (° C.) − 130 ° C.) or less is not preferable because the progress of the thermal oxidation process is remarkably slow.

  In order to obtain the effects of the present invention, it is most preferable to make a molded product using 100% of the PPS resin of the present invention, but if necessary, use of a blend with a PPS resin that does not satisfy the above conditions is excluded. It is not a thing. The blend ratio can be appropriately selected as necessary, such as blending 75 to 25% (for example, 75%, 50%, 25%) of the PPS resin of the present invention.

  The production method of the PPS resin before thermal oxidation treatment (hereinafter referred to as “pre-treatment PPS resin”), which is the basis of the PPS resin of the present invention, will be described in detail, but of course, as long as the requirements specified in the present invention are satisfied. The production method of the pre-PPS resin is not limited to the following.

  First, the contents of a polyhalogen aromatic compound, a sulfidizing agent, a polymerization solvent, a molecular weight regulator, a polymerization aid and a polymerization stabilizer used in the method for producing a pre-treatment PPS resin will be described.

[Polyhalogenated aromatic compounds]
The polyhalogenated aromatic compound used in the present invention refers to a compound having two or more halogen atoms in one molecule. Specific examples include p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene, 1,2,4,5-tetrachlorobenzene, hexa Polyhalogenated aromatics such as chlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene, 1-methoxy-2,5-dichlorobenzene Group compounds, and preferably p-dichlorobenzene is used. Further, it is possible to combine two or more different polyhalogenated aromatic compounds into a copolymer, but it is preferable to use a p-dihalogenated aromatic compound as a main component.

  The amount of the polyhalogenated aromatic compound used is 0.9 to 2.0 mol, preferably 0.95 to 1.5 mol, per mol of the sulfidizing agent, from the viewpoint of obtaining a PPS resin having a viscosity suitable for processing. More preferably, the range of 1.005 to 1.2 mol can be exemplified.

[Sulfiding agent]
Examples of the sulfidizing agent used in the present invention include alkali metal sulfides, alkali metal hydrosulfides, and hydrogen sulfide.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more of these, and sodium sulfide is preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  Specific examples of the alkali metal hydrosulfide include, for example, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide and a mixture of two or more of these. Preferably used. These alkali metal hydrosulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides.

  A sulfidizing agent prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Further, a sulfidizing agent can be prepared from alkali metal hydrosulfide and alkali metal hydroxide, and transferred to a polymerization tank for use.

  Alternatively, a sulfidizing agent prepared in situ in a reaction system from an alkali metal hydroxide such as lithium hydroxide or sodium hydroxide and hydrogen sulfide can also be used. Further, a sulfidizing agent can be prepared from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide, and transferred to a polymerization tank for use.

  In the present invention, the amount of the sulfidizing agent charged means the residual amount obtained by subtracting the loss from the actual charged amount when a partial loss of the sulfiding agent occurs before the start of the polymerization reaction due to dehydration operation or the like. Shall.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and a mixture of two or more thereof. Specific examples of the metal hydroxide include, for example, calcium hydroxide, strontium hydroxide, barium hydroxide, and sodium hydroxide is preferably used.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time, but the amount used is 0.95 to 1. A range of 20 mol, preferably 1.00 to 1.15 mol, more preferably 1.005 to 1.100 mol can be exemplified.

[Polymerization solvent]
In the present invention, an organic polar solvent is used as a polymerization solvent. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, and 1,3-dimethyl-2-imidazolide. Non-, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric acid triamide, dimethyl sulfone, tetramethylene sulfoxide and the like, and mixtures thereof, and the like are all included. It is preferably used because of its high reaction stability. Of these, N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP) is particularly preferably used.

  The amount of the organic polar solvent used is selected in the range of 2.0 to 10 mol, preferably 2.25 to 6.0 mol, more preferably 2.5 to 5.5 mol per mol of the sulfidizing agent. .

[Molecular weight regulator]
In the present invention, a monohalogen compound (not necessarily an aromatic compound) is converted to the polyhalogenated compound in order to form a terminal end of the pre-treatment PPS resin to be produced or to adjust a polymerization reaction or a molecular weight. It can be used in combination with an aromatic compound.

[Polymerization aid]
In the present invention, in order to obtain a pre-treatment PPS resin having a relatively high degree of polymerization in a shorter time, it is one of preferred embodiments to use a polymerization aid. Here, the polymerization assistant means a substance having an action of increasing the viscosity of the resulting polyarylene sulfide resin. Specific examples of such polymerization aids include, for example, organic carboxylates, water, alkali metal chlorides, organic sulfonates, alkali metal sulfates, alkaline earth metal oxides, alkali metal phosphates and alkaline earths. Metal phosphates and the like. These may be used alone or in combination of two or more. Of these, organic carboxylates and / or water are preferably used.

  The alkali metal carboxylate is a general formula R (COOM) n (wherein R is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an alkylaryl group, or an arylalkyl group). M is an alkali metal selected from lithium, sodium, potassium, rubidium and cesium, and n is an integer of 1 to 3). Alkali metal carboxylates can also be used as hydrates, anhydrides or aqueous solutions. Specific examples of the alkali metal carboxylate include, for example, lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, sodium benzoate, sodium phenylacetate, potassium p-toluate, and mixtures thereof. Can be mentioned.

  The alkali metal carboxylate is an organic acid and one or more compounds selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, and alkali metal bicarbonates, and are allowed to react by adding approximately equal chemical equivalents. You may form by. Among the alkali metal carboxylates, lithium salts are highly soluble in the reaction system and have a large auxiliary effect, but are expensive, and potassium, rubidium and cesium salts are insufficiently soluble in the reaction system. Therefore, sodium acetate, which is inexpensive and has an appropriate solubility in the polymerization system, is most preferably used.

  The amount used in the case of using these polymerization aids is usually in the range of 0.01 mol to 0.7 mol with respect to 1 mol of the charged alkali metal sulfide, and 0.1 to 0.1 in terms of obtaining a higher degree of polymerization. The range of 0.6 mol is preferable, and the range of 0.2 to 0.5 mol is more preferable.

  The use of water as a polymerization aid is one of the effective means for obtaining a resin composition in which fluidity and high toughness are highly balanced. In that case, the addition amount is usually in the range of 0.5 mol to 15 mol with respect to 1 mol of the charged alkali metal sulfide, and in the sense of obtaining a higher degree of polymerization, the range of 0.6 to 10 mol is preferable. The range of 1-5 mol is more preferable.

  There is no particular designation as to the timing of addition of these polymerization aids, which may be added at any time during the previous step, polymerization start, polymerization in the middle to be described later, or may be added in multiple times. When using an alkali metal carboxylate as a polymerization aid, it is more preferable to add it at the start of the previous step or at the start of the polymerization from the viewpoint of easy addition. When water is used as a polymerization aid, it is effective to add the polyhalogenated aromatic compound during the polymerization reaction after charging.

[Polymerization stabilizer]
In the present invention, a polymerization stabilizer may be used to stabilize the polymerization reaction system and prevent side reactions. The polymerization stabilizer contributes to stabilization of the polymerization reaction system and suppresses undesirable side reactions. One measure of the side reaction is the generation of thiophenol, and the addition of a polymerization stabilizer can suppress the generation of thiophenol. Specific examples of the polymerization stabilizer include compounds such as alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides, and alkaline earth metal carbonates. Among these, alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide are preferable. Since the alkali metal carboxylate described above also acts as a polymerization stabilizer, it is one of the polymerization stabilizers used in the present invention. In addition, when an alkali metal hydrosulfide is used as a sulfidizing agent, it has been described above that it is particularly preferable to use an alkali metal hydroxide at the same time. Oxides can also be polymerization stabilizers.

  These polymerization stabilizers can be used alone or in combination of two or more. The polymerization stabilizer is usually in a proportion of 0.02 to 0.2 mol, preferably 0.03 to 0.1 mol, more preferably 0.04 to 0.09 mol, relative to 1 mol of the charged alkali metal sulfide. Is preferably used. If this ratio is small, the stabilizing effect is insufficient. Conversely, if it is too much, it is economically disadvantageous and the polymer yield tends to decrease.

  The addition timing of the polymerization stabilizer is not particularly specified, and may be added at any time during the previous step, at the start of polymerization, or during the polymerization described later, or may be added in multiple times. It is more preferable to add at the start of the process or at the start of the polymerization from the viewpoint of easy addition.

  Next, the method for producing the pre-treatment PPS resin of the present invention will be specifically described in the order of the pre-process, the polymerization reaction process, the recovery process, and the post-treatment process.

[pre-process]
In the method for producing a PPS resin used in the present invention, the sulfiding agent is usually used in the form of a hydrate. Before adding the polyhalogenated aromatic compound, a mixture containing the organic polar solvent and the sulfiding agent is added. It is preferable to raise the temperature and remove excess water out of the system. In addition, when water is removed excessively by this operation, it is preferable to add and replenish the deficient water.

  Further, as described above, an alkali metal sulfide prepared from an alkali metal hydrosulfide and an alkali metal hydroxide in situ in the reaction system or in a tank different from the polymerization tank is also used as the sulfidizing agent. be able to. Although there is no particular limitation on this method, desirably an alkali metal hydrosulfide and an alkali metal hydroxide are added to the organic polar solvent in an inert gas atmosphere at a temperature ranging from room temperature to 150 ° C., preferably from room temperature to 100 ° C. In addition, there is a method in which the temperature is raised to at least 150 ° C. or more, preferably 180 to 260 ° C. under normal pressure or reduced pressure, and water is distilled off. A polymerization aid may be added at this stage. Moreover, in order to accelerate | stimulate distillation of a water | moisture content, you may react by adding toluene etc.

  The amount of water in the polymerization system in the polymerization reaction is preferably 0.5 to 10.0 moles per mole of the charged sulfidizing agent. Here, the amount of water in the polymerization system is an amount obtained by subtracting the amount of water removed from the polymerization system from the amount of water charged in the polymerization system. In addition, the water to be charged may be in any form such as water, an aqueous solution, and crystal water.

[Polymerization reaction step]
In the present invention, it is preferable to produce PPS resin particles by reacting a sulfidizing agent and a polyhalogenated aromatic compound in an organic polar solvent within a temperature range of 200 ° C. or higher and lower than 290 ° C.

  When starting the polymerization reaction step, the sulfidizing agent and the polyhalogenated aromatic compound are added to the organic polar solvent in an inert gas atmosphere at a temperature ranging from room temperature to 220 ° C, preferably 100 to 220 ° C. A polymerization aid may be added at this stage. The order in which these raw materials are charged may be out of order or may be simultaneous.

  The mixture is usually heated to a temperature in the range of 200 ° C to 290 ° C. Although there is no restriction | limiting in particular in a temperature increase rate, Usually, the speed of 0.01-5 degreeC / min is selected, and the range of 0.1-3 degreeC / min is more preferable.

  In general, the temperature is finally raised to a temperature of 250 to 290 ° C., and the reaction is usually carried out at that temperature for 0.25 to 50 hours, preferably 0.5 to 20 hours.

  In the stage before reaching the final temperature, for example, a method of reacting at 200 to 260 ° C. for a certain time and then raising the temperature to 270 to 290 ° C. is effective in obtaining a higher degree of polymerization. Under the present circumstances, as reaction time in 200 to 260 degreeC, the range of 0.25 to 20 hours is normally selected, Preferably the range of 0.25 to 10 hours is selected.

  In order to obtain a polymer having a higher degree of polymerization, it is effective to perform polymerization in a plurality of stages. When the polymerization is performed in a plurality of stages, it is effective that the conversion of the polyhalogenated aromatic compound in the system at 245 ° C. reaches 40 mol% or more, preferably 60 mol%.

  The conversion rate of the polyhalogenated aromatic compound (herein abbreviated as PHA) is a value calculated by the following formula. The residual amount of PHA can usually be determined by gas chromatography.

(A) When polyhalogenated aromatic compound is added excessively in a molar ratio with respect to the alkali metal sulfide Conversion rate = [PHA charge (mol) −PHA remaining amount (mol)] / [PHA charge (mol) -PHA excess (mole)]

(B) In cases other than the above (a) Conversion rate = [PHA charge (mol) −PHA remaining amount (mol)] / [PHA charge (mol)]

[Recovery process]
In the method for producing a pre-treatment PPS resin of the present invention, solids are recovered from a polymerization reaction product containing a polymer, a solvent and the like after the completion of polymerization.

The most preferable method for recovering the pre-treatment PPS resin of the present invention is to perform under rapid cooling conditions, and one preferable method for this recovery method is a flash method. In the flash method, the polymerization reaction product is flushed from a high-temperature and high-pressure state (usually 250 ° C. or higher, 8 kg / cm ² or higher) into an atmosphere of normal pressure or reduced pressure, and simultaneously with solvent recovery, the polymer is made into a granular form. This is a recovery method, and the term “flush” here means that a polymerization reaction product is ejected from a nozzle. Specific examples of the atmosphere to be flushed include nitrogen or water vapor at normal pressure, and the temperature is usually selected from the range of 150 ° C to 250 ° C.

  The flash method is a recovery method that is excellent in economic efficiency because it can recover the solids simultaneously with the recovery of the solvent and the recovery time can be relatively short. In this recovery method, an ionic compound typified by Na or an organic low-polymerization product (oligomer) tends to be easily taken into the polymer during the solidification process.

  However, the recovery method of the present invention is not limited to the flash method. If it is a method satisfying the requirements of the present invention, it is not easy to use a method (quenching method) of slow cooling to recover the particulate polymer. However, in view of economy and performance, it is more preferable to use the pre-treatment PPS resin of the present invention recovered by the flash method.

[Post-processing process]
The pre-treatment PPS resin of the present invention may be produced through the above polymerization and recovery steps and then subjected to acid treatment, hot water treatment or washing with an organic solvent.

  When acid treatment is performed, it is as follows. The acid used for the acid treatment of the PPS resin in the present invention is not particularly limited as long as it does not have an action of decomposing the PPS resin, and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, and propyl acid. Of these, acetic acid and hydrochloric acid are more preferably used, but those that decompose and deteriorate the PPS resin such as nitric acid are not preferable.

  As the acid treatment method, there is a method of immersing the PPS resin in an acid or an acid aqueous solution, and it is possible to appropriately stir or heat as necessary. For example, when acetic acid is used, a sufficient effect can be obtained by immersing the PPS resin in an aqueous PH4 solution heated to 80 to 200 ° C. and stirring for 30 minutes. The PH after processing may be 4 or more, for example, about PH 4-8. The acid-treated PPS resin is preferably washed several times with water or warm water in order to remove residual acid or salt. The water used for washing is preferably distilled water or deionized water in the sense that the effect of the preferred chemical modification of the PPS resin by acid treatment is not impaired.

  When performing hot water treatment, it is as follows. In the hydrothermal treatment of the PPS resin particles used in the present invention, the temperature of the hot water is 100 ° C. or higher, more preferably 120 ° C. or higher, further preferably 150 ° C. or higher, and particularly preferably 170 ° C. or higher. preferable. If it is less than 100 ° C., the effect of preferable chemical modification of the PPS resin is small, which is not preferable.

  The water used is preferably distilled water or deionized water in order to express the preferable chemical modification effect of the PPS resin by the hot water washing of the present invention. There is no particular limitation on the operation of the hot water treatment, and a predetermined amount of PPS resin is put into a predetermined amount of water and heated and stirred in a pressure vessel, or a continuous hot water treatment is performed. The ratio of the PPS resin to water is preferably larger, but usually a bath ratio of 200 g or less of PPS resin is selected for water 1.

  Further, since the decomposition of the terminal group is not preferable, the treatment atmosphere is preferably an inert atmosphere in order to avoid this. Further, the PPS resin after the hot water treatment operation is preferably washed several times with warm water in order to remove remaining components.

  When washing with an organic solvent, it is as follows. The organic solvent used for washing the PPS resin in the present invention is not particularly limited as long as it does not have an action of decomposing the PPS resin. For example, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, 1, 3 -Nitrogen-containing polar solvents such as dimethylimidazolidinone, hexamethylphosphoramide, piperazinones, sulfoxide-sulfon solvents such as dimethyl sulfoxide, dimethyl sulfone, sulfolane, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, Ether solvents such as dimethyl ether, dipropyl ether, dioxane, tetrahydrofuran, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchlorethylene, monochloroethane, dichloroethane, teto Halogen solvents such as chloroethane, perchlorethane, chlorobenzene, alcohol / phenol solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, polyethylene glycol, polypropylene glycol, and benzene, Examples thereof include aromatic hydrocarbon solvents such as toluene and xylene. Among these organic solvents, use of N-methyl-2-pyrrolidone, acetone, dimethylformamide, chloroform and the like is particularly preferable, and these organic solvents are used alone or in combination of two or more.

  As a method of washing with an organic solvent, there is a method of immersing a PPS resin in an organic solvent, and if necessary, stirring or heating can be appropriately performed. There is no restriction | limiting in particular about the washing | cleaning temperature at the time of wash | cleaning PPS resin with an organic solvent, Arbitrary temperature of about normal temperature-about 300 degreeC can be selected. Although the cleaning efficiency tends to increase as the cleaning temperature increases, a sufficient effect is usually obtained at a cleaning temperature of room temperature to 150 ° C. It is also possible to wash under pressure in a pressure vessel at a temperature above the boiling point of the organic solvent. There is no particular limitation on the cleaning time. Depending on the cleaning conditions, in the case of batch-type cleaning, a sufficient effect can be obtained usually by cleaning for 5 minutes or more. It is also possible to wash in a continuous manner.

  These acid treatment, hot water treatment or washing with an organic solvent can be carried out by appropriately combining them.

  Preferred PPS resins before thermal oxidation used in the present invention include Toray's M2888, M3088, L2480, L4230, M3910, Kureha Chemical Industries W205A, and the like.

By subjecting the pre-treatment PPS resin obtained by the above production method to a thermal oxidation treatment by heating in an oxygen atmosphere or by adding a peroxide such as H ₂ O ₂ or a vulcanizing agent such as S, Although the PPS resin of the present invention can be obtained, a thermal oxidation treatment method by heating in an oxygen atmosphere is particularly preferable because of simple treatment.

  The heating device for the thermal oxidation treatment may be a normal hot air dryer or a heating device with a rotary type or a stirring blade. However, for efficient and more uniform processing, a rotary type or a stirring blade is used. It is more preferable to use the heating device. The oxygen concentration during the thermal oxidation treatment is preferably 2% by volume or more, and more preferably 8% by volume or more. Although there is no restriction | limiting in particular in the upper limit of oxygen concentration, About 50 volume% is a limit and 25 volume% or less is more preferable. Preferred temperature conditions for the thermal oxidation treatment are as described above. Treatment time includes 0.5 to 50 hours, more preferably 0.5 to 20 hours, and further preferably 0.5 to 10 hours.

  Further, before and after the thermal oxidation treatment, it is possible to suppress thermal oxidation cross-linking and perform a dry heat treatment for the purpose of removing volatile components and moisture. The temperature is preferably 130 to 250 ° C, and more preferably 160 to 250 ° C. In this case, the oxygen concentration is preferably less than 2% by volume. The treatment time is preferably 0.5 to 50 hours, more preferably 1 to 20 hours, and further preferably 1 to 10 hours. The heat treatment apparatus may be a normal hot air dryer or a heating apparatus with a rotary blade or a stirring blade. However, for efficient and more uniform treatment, a heating device with a rotary blade or a stirring blade is used. Is more preferable.

  The PPS resin of the present invention thus obtained is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is particularly suitably applied to injection molding applications and the like.

  In addition, it is also possible to add other resin to the PPS resin of this invention in the range which does not impair the effect of this invention. For example, the flexibility and impact resistance can be further improved by adding a small amount of a highly flexible thermoplastic resin. However, if this amount exceeds 50% by weight of the total composition, the original characteristics of the PPS resin are impaired, and in particular, addition of 30% by weight or less is preferably used. Specific examples of thermoplastic resins include epoxy group-containing olefin copolymers, other olefin resins, polyamide resins, polybutylene terephthalate resins, polyethylene terephthalate resins, polyphenylene ether resins, polysulfone resins, polyallyl sulfone resins, polyketones. Resin, polyetherimide resin, polyarylate resin, liquid crystal polymer, polyethersulfone resin, polyetherketone resin, polythioetherketone resin, polyetheretherketone resin, polyimide resin, polyamideimide resin, tetrafluoropolyethylene resin, etc. Can be mentioned.

  Moreover, the following compounds can be added for the purpose of modification. Coupling agents such as isocyanate compounds, organosilane compounds, organotitanate compounds, organoborane compounds, epoxy compounds, polyalkylene oxide oligomer compounds, thioether compounds, ester compounds, organophosphorus compounds, etc. , Talc, kaolin, organophosphorus compounds, crystal nucleating agents such as polyetheretherketone, montanic acid waxes, metal soaps such as lithium stearate and aluminum stearate, ethylenediamine / stearic acid / sebacic acid polycondensates, silicone compounds Other additives such as mold release agents such as hypophosphites, lubricants, UV inhibitors, colorants, foaming agents and the like can be blended. If any of the above compounds exceeds 20% by weight of the total composition, the original properties of the PPS resin are impaired, and therefore it is not preferred, and 10% by weight or less, more preferably 1% by weight or less is added.

  The PPS resin of the present invention has at least one functional group selected from an epoxy group, an amino group, an isocyanate group, a hydroxyl group, a mercapto group, and a ureido group for the purpose of improving mechanical strength and toughness. You may add the alkoxysilane which has. Specific examples of such compounds include epoxy group-containing alkoxysilanes such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. Compounds, mercapto group-containing alkoxysilane compounds such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ- (2-ureidoethyl) ) Ureido group-containing alkoxysilane compounds such as aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-isocyanatopropyltrimethoxysilane, γ-isocyanatopropylmethyldimethoxysilane, Isocyanato group-containing alkoxysilane compounds such as γ-isocyanatopropylmethyldiethoxysilane, γ-isocyanatopropylethyldimethoxysilane, γ-isocyanatopropylethyldiethoxysilane, γ-isocyanatopropyltrichlorosilane, γ- (2- Amino group-containing alkoxysilane compounds such as aminoethyl) aminopropylmethyldimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-hydroxypropyltrimethoxysilane, γ- Examples thereof include a hydroxyl group-containing alkoxysilane compound such as hydroxypropyltriethoxysilane.

  A suitable addition amount of the silane compound is selected in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the polyphenylene sulfide resin.

  The PPS resin of the present invention can be used by blending a filler as long as the effects of the present invention are not impaired. Specific examples of such fillers include glass fiber, carbon fiber, basalt fiber, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber, ceramic fiber. , Fibrous fillers such as asbestos fiber, stone fiber, metal fibers, or silicates such as talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, bentonite, asbestos, alumina silicate, oxidation Metal compounds such as silicon, magnesium oxide, alumina, zirconium oxide, titanium oxide and iron oxide, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfates such as calcium sulfate and barium sulfate, calcium hydroxide Non-fibrous fillers such as hydroxides such as magnesium hydroxide and aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, carbon nanotubes, fullerene, boron nitride, silicon carbide, carbon black and silica, graphite These may be hollow, and two or more of these fillers may be used in combination. These fillers may be used after pretreatment with a coupling agent such as an isocyanate compound, an organic silane compound, an organic titanate compound, an organic borane compound, and an epoxy compound.

  The amount of the inorganic filler is usually preferably in the range of 0.0001 to 500 parts by weight and more preferably in the range of 0.001 to 400 parts by weight with respect to 100 parts by weight of the polyphenylene sulfide resin. The content of the inorganic filler can be appropriately changed depending on the application from the balance of strength, rigidity, and other characteristics.

  The kneading machine is a method of kneading at a processing temperature of the melting peak temperature of the PPS resin +5 to 60 ° C. by supplying it to a generally known melt kneader such as a single-screw, twin-screw extruder, Banbury mixer, kneader, and mixing roll. Can be cited as a representative example. When using the auxiliary materials, the mixing order of the raw materials is not particularly limited, and a method in which all raw materials are blended and then melt-kneaded by the above method, a part of the raw materials are blended and then melt-kneaded by the above method, and the remaining raw materials Any method may be used, such as a method of blending and melt-kneading a mixture of materials, or a method of mixing the remaining raw materials using a side feeder during melt-kneading with a single-screw or twin-screw extruder after blending some raw materials. Good. As for the small amount additive component, other components can be kneaded by the above-mentioned method and pelletized, then added before molding and used for molding.

  The PPS resin of the present invention can be applied to injection molded products, films, sheets, fibers and the like.

  The polyarylene sulfide resin (composition) of the present invention thus obtained is particularly suitable for injection molding applications. Specific examples of such applications include sensors, LED lamps, connectors, sockets, resistors, and relay cases. , Switch, coil bobbin, condenser, variable capacitor case, optical pickup, oscillator, various terminal boards, transformer, plug, printed circuit board, tuner, speaker, microphone, headphones, small motor, magnetic head base, power module, semiconductor, liquid crystal, Electrical / electronic parts such as FDD carriage, FDD chassis, motor brush holder, parabolic antenna, computer-related parts; VTR parts, TV parts, irons, hair dryers, rice cooker parts, microwave oven parts, acoustic parts, audio equipment Audio equipment parts such as DIO, laser discs, compact discs, lighting parts, refrigerator parts, air conditioner parts, typewriter parts, word processor parts, household electrical appliance parts, office computer related parts, telephone related parts, Machine-related parts such as facsimile-related parts, copier-related parts, cleaning jigs, motor parts, lighters, typewriters, etc .: optical equipment such as microscopes, binoculars, cameras, watches, precision machine-related parts; Water faucet tops, mixing faucets, pump parts, pipe joints, water volume control valves, relief valves, hot water temperature sensors, water volume sensors, water meter housings and other water-related parts; valve alternator terminals, alternator connectors, IC regulators, light dials Poten for Various valves such as ohmmeter base, exhaust gas valve, various pipes related to fuel, exhaust system, intake system, air intake nozzle snorkel, intake manifold, fuel pump, engine coolant joint, carburetor main body, carburetor spacer, exhaust gas sensor, cooling Water sensor, oil temperature sensor, throttle position sensor, crankshaft position sensor, air flow meter, brake pad wear sensor, thermostat base for air conditioner, heating hot air flow control valve, brush holder for radiator motor, water pump impeller, turbine vane, Wiper motor related parts, distributor, starter switch, starter relay, transmission wire , Window washer nozzle, air conditioner panel switch board, coil for fuel-related electromagnetic valve, connector for fuse, horn terminal, electrical component insulation plate, step motor rotor, lamp socket, lamp reflector, lamp housing, brake piston, solenoid bobbin, engine Automotive and vehicle-related parts such as oil filters, ignition device cases, vehicle speed sensors, cable liners, engine control unit cases, engine driver unit cases, condenser cases, motor insulation materials, hybrid car control system parts cases, and other various applications It can be illustrated.

  The present invention will be described more specifically with reference to the following examples.

  In the following examples, material characteristics were measured by the following method.

[Gas generation amount]
3 g of PPS resin was weighed into a glass ampoule having an abdomen of 100 mm × 25 mm, a neck of 255 mm × 12 mm, and a wall thickness of 1 mm, followed by vacuum sealing. Only the barrel of this glass ampoule was inserted into a ceramic electric tubular furnace ARF-30K manufactured by Asahi Rika Seisakusho and heated at 320 ° C. for 2 hours. After the ampoule was taken out, the neck of the ampoule that was not heated by the tubular furnace and was attached with volatile gas was cut out with a file and weighed. Next, the adhering gas was dissolved and removed with 5 g of chloroform, dried for 1 hour in a glass dryer at 60 ° C., and then weighed again. The difference in weight between the neck of the ampoule before and after removing the gas was taken as the amount of gas generated.

[Remaining amount]
A SUS test tube made by Senshu Kagaku equipped with a pneumatic cap and a collecting funnel is set with a PTFE membrane filter with a pore size of 1 μm, which has been previously weighed, and 100 mg of PPS resin and 1-chloronaphthalene formed into a press film to a thickness of about 80 μm. 2 g was weighed in and sealed. This was inserted into a high-temperature filtration device SSC-9300 manufactured by Senshu Kagaku, and the PPS resin was dissolved in 1-chloronaphthalene by heating and shaking at 250 ° C. for 5 minutes. After connecting a 20 mL syringe containing air to the pneumatic cap, the piston was extruded and the solution was filtered through a membrane filter. The membrane filter was taken out, vacuum-dried at 150 ° C. for 1 hour, and then weighed. The difference in membrane filter weight before and after filtration was defined as the residual amount.

[MFR]
The measurement temperature was 315.5 ° C. and the load was 5000 g, and the measurement was performed by a method according to ASTM-D1238-70.

[Melt viscosity]
Using a Capillograph 1C manufactured by Toyo Seiki Co., Ltd., melt viscosity was measured at 300 ° C. using a die having a hole length of 10.00 mm and a hole diameter of 0.50 mm.

[Average particle size]
The particle diameter (D50) corresponding to 50% of the cumulative distribution obtained by measurement by the sieving method was determined and used as the average particle diameter. Specifically, FRITSCH-ELECTROMAGNETIC LABORATORY SIEVE SHAKER was used as a shaker, and a standard stainless steel sieve (diameter 203 mm, depth 45 mm) was set. The standard sieve mesh has a combination of 20 mesh, 32 mesh, 60 mesh, 200 mesh and 330 mesh when the particle size is relatively fine, and 4 mesh, 7 mesh, 14 mesh and 20 mesh when the particle size is relatively rough. A combination of mesh, 32 mesh, and 60 mesh was used. 110 ± 0.1 g of the PPS sample was weighed, and 1.1 ± 0.1 g of carbon black (which passes 330 mesh) was added thereto for antistatic purposes, and mixed in a plastic bag. The PPS sample (100 ± 0.1 g) was placed in the uppermost standard sieve of a shaker equipped with a standard sieve, then covered and shaken for 30 minutes. Thereafter, the amount of sample remaining on each shake was weighed with an accuracy of ± 0.1 g, and the opening (μm) corresponding to each mesh and the accumulated weight were plotted, and the particle diameter corresponding to 50% of the accumulated distribution (D50) Asked.

[Measurement of melting point (Tm)]
Using a DSC7 manufactured by PerkinElmer, the sample amount was about 10 mg, in a nitrogen atmosphere, at a temperature increase / decrease rate of 20 ° C./minute, the temperature was increased to 340 ° C. at 50 ° C., held at 340 ° C. for 1 minute, and decreased to 100 ° C. Thereafter, the melting peak temperature when the temperature was raised again was defined as the melting point (Tm).

[Bending strength and flexural modulus]
Measurements were performed according to ASTM D790. Specifically, the measurement was performed as follows. The resin composition pellets of the present invention are supplied to an injection molding machine (SG75-HIPRO · MIII) manufactured by Sumitomo-Nestal Co., which is set to a cylinder temperature of 330 ° C., and injection pressure = molding lower limit pressure + 5 Kgf / cm ² gauge pressure. Injection molding was performed to obtain a test piece having a width of 12.7 mm, a height of 6.4 mm, and a length of 127 mm. Using this test piece, measurement was performed under the conditions of a span of 100 mm and a strain rate of 3 mm / min in an atmosphere of 23 ° C. and a relative humidity of 50%.

[Reference Example 1] Preparation of PPS-1 In an autoclave with a stirrer and a valve at the bottom, 8267.4 g (70.0 mol) of 47.5% sodium hydrosulfide and 2925.0 g (70. 2 mol), 13860.0 g (140.0 mol) of N-methyl-2-pyrrolidone (NMP), 2238.6 g (27.3 mol) of sodium acetate, and 10500.0 g of ion-exchanged water, and nitrogen at normal pressure The mixture was gradually heated to 240 ° C. over about 3 hours while distilling through water, and after distilling out 14772.1 g of water and 280.0 g of NMP, the reaction vessel was cooled to 160 ° C. The residual water content in the system per 1 mol of the charged alkali metal sulfide was 1.08 mol including the water consumed for the hydrolysis of NMP. The amount of hydrogen sulfide scattered was 0.023 mol per mol of the alkali metal sulfide charged.

  Next, 10435.4 g (71.0 mol) of p-dichlorobenzene (p-DCB) and NMP6444.9 g (65.1 mol) were added, the reaction vessel was sealed under nitrogen gas, and stirred at 240 rpm. The temperature was raised from 200 ° C. to 250 ° C. at a rate of 0.8 ° C./min, and held at 250 ° C. for 70 minutes. Next, the temperature was raised from 250 ° C. to 278 ° C. at a rate of 0.8 ° C./min, and maintained at 278 ° C. for 78 minutes. The extraction valve at the bottom of the autoclave was opened, and the contents were flushed into a vessel equipped with a stirrer over 15 minutes while being pressurized with nitrogen, and stirred for a while at 250 ° C. to remove most of NMP.

  The obtained solid and 53 liters of ion-exchanged water were placed in an autoclave equipped with a stirrer, washed at 70 ° C. for 30 minutes, and then suction filtered through a glass filter. Next, 60 liters of ion exchange water heated to 70 ° C. was poured into a glass filter, and suction filtered to obtain a cake.

  Acetic acid was added so that the obtained cake and ion-exchanged water 90 liters and pH was 7, and then charged into an autoclave equipped with a stirrer. After the inside of the autoclave was replaced with nitrogen, the temperature was raised to 192 ° C. and held for 30 minutes. . Thereafter, the autoclave was cooled and the contents were taken out.

  The contents were subjected to suction filtration with a glass filter, and then 76 liters of ion-exchanged water at 70 ° C. was poured into the contents to perform suction filtration to obtain a cake. The obtained cake was dried at 120 ° C. under a nitrogen stream to obtain dry PPS.

  The obtained PPS-1 had an MFR of 720 g / 10 min, a melting point (Tm) = 282 ° C., and an average particle size of 320 μm.

[Reference Example 2] Preparation of PPS-2 Polymerization was carried out in the same manner as Reference Example 1 except that sodium acetate was not added during the polymerization.

  The obtained PPS-2 had a melt viscosity of 5 Pa · s (300 ° C., shear rate of 1000 / sec), a melting point (Tm) = 282 ° C., and an average particle size of 60 μm. In addition, since the melt viscosity of the polymer with MFR = 500 g / 10 min is about 80 Pa · s (300 ° C., shear rate 1000 / sec), PPS-2 has an MFR of 500 g / 10 min or more.

[Examples 1 and 2, Comparative Examples 1, 2, and 3]
PPS-1 was subjected to a thermal oxidation treatment in an air atmosphere under the conditions shown in Table 1, and MFR, gas generation amount and residual amount were measured. The results are shown in Table 1 and FIG. As can be seen from Comparative Example 2, when the thermal oxidation treatment is too small, the amount of gas generated increases. On the other hand, as can be seen from Comparative Example 3, the excessive thermal oxidation treatment saturates the gas generation amount reduction effect and tends to decrease only the melt viscosity.

[Example 3, Comparative Examples 4 and 5]
PPS-2 was subjected to thermal oxidation treatment in the air atmosphere under the conditions shown in Table 2, and MFR and / or melt viscosity, gas generation amount, and residual amount were measured. The results are shown in Table 2.

[Example 4]
After dry blending 100 parts by weight of PPS of Example 2 and 67 parts by weight of glass fiber (ECS03TN-103 / P manufactured by Nippon Electric Glass Co., Ltd.), a TEX30α type twin screw extruder (L / D = 45. 5), the temperature was set so that the cylinder discharge resin temperature was 320 ° C. at a screw rotation speed of 300 rpm, melt kneaded, and pelletized with a strand cutter. Pellets dried overnight at 120 ° C. were used for injection molding. When the bending strength and bending elastic modulus of the sample were measured, the bending strength was 230 MPa and the bending elastic modulus was 11.5 GPa.

[Comparative Example 6]
Melt kneading and injection molding were performed in the same manner as in Example 4 except that PPS of Comparative Example 2 was used. When the bending strength and bending elastic modulus of the sample were measured, the bending strength was 180 MPa and the bending elastic modulus was 11.0 GPa.

  According to the present invention, a polyphenylene sulfide resin having a melt fluidity and a small amount of volatile components at the time of melting can be obtained.

It is a figure which shows the relationship between MFR in Examples 1, 2 and Comparative Examples 1-3, and gas generation amount.

Claims (6)

It is made of polyphenylene sulfide resin that has been subjected to thermal oxidation treatment. The amount of gas that evaporates when heated and melted at 320 ° C for 2 hours under vacuum is 0.3% by weight or less, and at 250 ° C for 5 minutes, 20 times. The amount of residue when dissolved by weight of 1-chloronaphthalene and filtered under pressure with a PTFE membrane filter having a pore size of 1 μm is 4.0% by weight or less, and the melt flow rate (according to ASTM D-1238-70) (Measured at a temperature of 315.5 ° C. and a load of 5000 g.) A polyphenylene sulfide resin having a weight exceeding 500 g / 10 minutes. 2. The polyphenylene sulfide resin according to claim 1, which comprises a polyphenylene sulfide resin which has been subjected to a thermal oxidation treatment and has an average particle size exceeding 50 μm. The polyphenylene sulfide resin according to claim 1 or 2, wherein the polyphenylene sulfide resin is a polyphenylene sulfide resin recovered by a flash method. The method for producing a polyphenylene sulfide resin according to any one of claims 1 to 3, wherein the thermal oxidation treatment temperature (Tc) has the following relationship with the melting point (Tm) of the polyphenylene sulfide resin before the thermal oxidation treatment. .
Tm (° C.) − 130 ° C. <Tc <Tm (° C.) − 70 ° C. 5. The method for producing a polyphenylene sulfide resin according to claim 4, wherein the polyphenylene sulfide resin is a polyphenylene sulfide resin recovered by a flash method. A molded article obtained by injection molding the polyphenylene sulfide resin according to any one of claims 1 to 3 or the polyphenylene sulfide resin obtained by the production method according to any one of claims 4 to 5.

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