JP2008208177A - Polyphenylene sulfide blow molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PPS (polyphenylene sulfide) blow molded product having an extremely small amount of eluted ionic impurities or organic materials by using PPS resin in which the molecular weight distribution is narrow and the amount of metal impurities is reduced and to provide a method for producing the molded product. <P>SOLUTION: The PPS blow molded product is composed of the PPS and is characterized as follows: the weight-average molecular weight (Mw) is ≥10,000 and ≤2.5 dispersity represented by the Mw/number-average molecular weight (Mn). The alkali metal content is ≤50 ppm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a polyphenylene sulfide hollow molded article with an extremely small amount of elution of ionic impurities and organic substances and a method for producing the same.

  A polyphenylene sulfide resin (hereinafter sometimes abbreviated as a PPS resin) has been put into practical use as an engineering plastic by taking advantage of excellent heat resistance and chemical resistance. In particular, it has excellent heat resistance, chemical resistance, rigidity, flame retardancy, and has excellent molding processability and dimensional stability. Therefore, it is used as an engineering plastic for injection molding, as an electrical / electronic equipment part, an automobile part, and a precision equipment part. Widely used. Taking advantage of its chemical resistance, it is also being developed into pipes, containers and supply tubes for ultrapure water and high purity solvents.

  By the way, as a specific method for producing the PPS resin, there is a method of reacting an alkali metal sulfide such as sodium sulfide and a polyhaloaromatic compound such as p-dichlorobenzene in an organic amide solvent such as N-methyl-2-pyrrolidone. This method has been proposed and is widely used as an industrial production method for PPS resins.

  Since this polymerization reaction is a desalting polycondensation mechanism, a by-product salt such as sodium chloride is produced in a large amount. Therefore, a by-product salt removal step is required after the polymerization reaction, but it is difficult to completely remove the by-product salt by ordinary treatment, and the commercially available general-purpose PPS resin has an alkali metal content of about 150 to 3000 ppm. Contained. In addition, the PPS resin obtained by this method is a polymer that contains a relatively large amount of low molecular weight components, has a large degree of dispersion represented by the ratio of the weight average molecular weight and the number average molecular weight, and has a wide molecular weight distribution.

  In recent years, especially with the miniaturization of semiconductor manufacturing applications, there is a concern that even a very small amount of metal, especially alkali metal such as sodium, may cause a decrease in performance and yield of semiconductor elements. The demand for ultra-high purity of high-purity solvents is increasing, and the level of residual metal contained in conventional PPS resins may be insufficient to expand into such applications for the latest semiconductor devices. The demand for pipes, tubes and containers made of low metal elution PPS is increasing.

  Another possible cause of microorganisms that propagate in ultrapure water is organic substances that elute from pipes, tubes, and containers. Although PPS resins used in the existing PPS for the semiconductor industry and for highly soluble refrigerants and oils have been used in varieties with a relatively low leaching amount of ionic impurities and organic substances, the requirement in recent years has been There are applications that cannot be separated by conventional PPS, and there is an increasing demand for PPS pipes, containers, and supply tubes that are small in leaching amount of organic substances as well as ionic impurities.

  As a method for improving one of the problems of the PPS resin, that is, PPS has many low molecular weight components and a wide molecular weight distribution, a mixture of PPS containing impurities is higher than the minimum temperature at which PPS forms a molten phase. In this state, a method of purifying impurities by subjecting them to thermal extraction by phase separation into a polymer melt phase containing PPS and a solvent phase mainly comprising solvent, or a method of precipitating and recovering granular polymer after cooling is proposed. Has been. Although these methods extract impurities due to the heat extraction effect, it is expected that the volatile gas components will be reduced and the molecular weight distribution will be narrowed. The improvement effect is not sufficient (for example, Patent Documents 1 and 2).

  As another method for improving the point that the PPS resin contains a large amount of low molecular weight components and has a wide molecular weight distribution, a sulfur source and a dihaloaromatic compound are mixed in an organic polar solvent at a temperature of 220 to 280 ° C. for 0.1 to 2%. The ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn produced is characterized in that the PPS resin obtained by reacting for a period of time is washed with an organic polar solvent at a temperature of 100 to 220 ° C. PPS resins in the range of are disclosed. In the production of the PPS resin, a low molecular weight component is removed by washing with an organic solvent at a high temperature to obtain a PPS resin having a narrow molecular weight distribution. Therefore, the yield of the PPS resin is low and substantially obtained. Even the lowest dispersibility PPS resin has Mw / Mn = 2.9, and the method uses a large amount of an expensive lithium compound in the polymerization of PPS, so the effect of suppressing the elution amount of organic matter is insufficient. there were. Further, there is a concern that the lithium used remains in the PPS, resulting in an increase in the amount of ionic impurities (see, for example, Patent Document 3).

  Further, as a method for producing a PPS resin having a narrow molecular weight distribution, a method in which a cyclic PPS oligomer is heated and subjected to ring-opening polymerization in the presence of an ionic ring-opening polymerization catalyst is disclosed. In this method, it can be expected to obtain a PPS resin having a narrow molecular weight distribution without performing a complicated organic solvent washing operation. However, in this method, since an alkali metal salt of sulfur, such as sodium thiophenol, is used as an essential component in the synthesis of PPS as a ring-opening polymerization catalyst, a large amount of alkali metal remains in the resulting PPS, and the effect of reducing ionic impurities is reduced. In this method, if the amount of the ring-opening polymerization catalyst is reduced in order to reduce the residual amount of alkali metal, the molecular weight of the obtained PPS becomes insufficient, and a melt viscosity sufficient for molding pipes and containers can be obtained. There was no problem. (For example, patent documents 4 and 5).

  The problem of PPS obtained by the above method, that is, as a method of reducing the residual amount of alkali metal in PPS, is PPS in which a cyclic aromatic thioether oligomer is subjected to ring-opening polymerization in the presence of a polymerization initiator that generates sulfur radicals by heating. A manufacturing method is disclosed. In this method, since a nonionic compound is used as the polymerization initiator, it is considered that the alkali metal content of the obtained PPS is reduced. However, the glass transition temperature of PPS obtained by this method is as low as 85 ° C., and this is because the molecular weight is low and the PPS contains a large amount of low molecular weight components and has a wide molecular weight distribution. It was insufficient. In addition, the polymerization initiator used in this method has a lower molecular weight than conventional PPS resins and is inferior in thermal stability. Therefore, when the PPS resin obtained by this method is heated, a large amount of gas is generated and moldability is increased. (For example, patent document 6).

Also known is a PPS polymerization method in which a mixture of cyclic PPS and linear PPS is heated as a monomer source (Non-patent Document 1). This method is an easy polymerization method for PPS, but the resulting PPS has a low degree of polymerization and is not suitable for practical use. Although this document discloses that the degree of polymerization can be improved by increasing the heating temperature, it still does not reach a molecular weight suitable for practical use, and in this case, the formation of a crosslinked structure is not achieved. Only PPS which cannot be avoided and inferior in thermal properties is obtained, and in order to produce a PPS hollow molded body, a high-quality PPS polymerization method more suitable for practical use has been desired.
Japanese Patent Publication No. 1-25493 (page 23) Japanese Patent Publication No. 4-55445 (pages 3-4) JP-A-2-182727 (pages 9-13) Japanese Patent No. 3216228 (pages 7 to 10) Japanese Patent No. 3141459 (pages 5-6) US Pat. No. 5,869,599 (pages 27-28) Polymer, vol. 37, no. 14, 1996 (pages 3111-3116)

  An object of the present invention is to provide a polyphenylene sulfide hollow molded body with a very small amount of ionic impurities and organic substances eluted and a method for producing the same.

As a result of studying to solve the above-mentioned problems, the present inventors have adopted a specific polymerization method, so that the amount of elution of ionic impurities and organic substances is extremely small and sufficiently high to withstand molding of pipes and containers. The present inventors have found that PPS having a degree of polymerization is obtained, and that PPS hollow molded bodies such as pipes, tubes, containers, and the like with very little elution amount of ionic impurities and organic substances can be obtained. That is, the present invention provides the following.
1. It is composed of polyphenylene sulfide having a weight average molecular weight (Mw) of 10,000 or more, a dispersity represented by weight average molecular weight / number average molecular weight (Mn) of 2.5 or less, and an alkali metal content of 50 ppm or less. A featured polyphenylene sulfide hollow molded body.
2. 2. The polyphenylene sulfide hollow molded article according to 1, wherein the alkali metal in the polyphenylene sulfide is sodium.
3. 1 or 2 characterized in that the lactone type compound in the generated gas component when the polyphenylene sulfide hollow molded body is heated is 500 ppm or less based on the weight of the polyphenylene sulfide, and the aniline type compound is 300 ppm or less based on the weight of the polyphenylene sulfide. The polyphenylene sulfide hollow molded article described.
4). The polyphenylene sulfide hollow molded article according to any one of 1 to 3, wherein the polyphenylene sulfide is polyphenylene sulfide obtained by melting and heating a cyclic polyphenylene sulfide mixture represented by the following general formula (1): .

(M may be an integer of 4 to 20, m may be a mixture of 4 to 20)
5. 5. The polyphenylene sulfide hollow molded body according to any one of 1 to 4, wherein the polyphenylene sulfide hollow body is formed by extrusion molding or blow molding.
6). 6. The polyphenylene sulfide hollow molded body according to 5, which is a tubular body formed by extrusion molding.
7). A polyphenylene sulfide hollow molded body characterized in that a polyphenylene sulfide obtained by melting and heating a cyclic polyphenylene sulfide mixture represented by the following general formula (1) is continuously melt-molded while maintaining a melt state. Manufacturing method.

(M may be an integer of 4 to 20, m may be a mixture of 4 to 20)
8). 8. The process for producing a polyphenylene sulfide hollow molded article according to 7, wherein the melt molding is extrusion molding or blow molding.

  INDUSTRIAL APPLICABILITY The present invention can provide a polyphenylene sulfide hollow molded body having a very small elution amount of ionic impurities and organic substances and a production method thereof. Such a hollow molded body is suitably used for piping pipes, tubes, containers and the like of ultrapure water or ultrahigh purity solvents.

  Hereinafter, the present invention will be described in detail.

(1) Polyphenylene sulfide hollow molded body (PPS)
The PPS used in the PPS hollow molded article of the present invention is a polymer containing 70 mol% or more, more preferably 90 mol% or more of the repeating unit represented by the structural formula (2). If it is less than mol%, the heat resistance is impaired.

  Further, PPS can constitute less than 30 mol% of the repeating units with repeating units having the following structural formula.

  The molecular weight of the PPS hollow molded article of the present invention is 10,000 or more, preferably 15,000 or more, more preferably 18,000 or more in terms of weight average molecular weight. When the weight average molecular weight is less than 10,000, the melt film-forming property is lowered, and the properties such as the mechanical strength of the hollow molded article are lowered. Although there is no restriction | limiting in particular in the upper limit of a weight average molecular weight, Less than 1,000,000 can be illustrated as a preferable range, More preferably, it is less than 500,000, More preferably, it is less than 200,000, Within this range, it is high moldability. Can be obtained.

  The dispersion of the molecular weight distribution of the PPS hollow molded article in the present invention, that is, the degree of dispersion represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.5 or less, preferably 2.3 or less, more preferably 2.1 or less, and particularly preferably 2.0 or less. When the degree of dispersion exceeds 2.5, there is a strong tendency that the amount of low molecular weight components contained in PPS increases, and there are concerns about an increase in the amount of organic matter elution and gas generation during molding.

  The weight average molecular weight and the number average molecular weight can be calculated, for example, in terms of polystyrene by gel permeation chromatography (GPC) which is a kind of size exclusion chromatography (SEC).

The melt viscosity of the PPS hollow molded body used in the present invention is not particularly limited as long as it can be melt-kneaded, but usually 5 to 5000 Pa · s (300 ° C., shear rate 1000 sec ⁻¹ ) is used.

  The PPS hollow molded article of the present invention is characterized by being higher in purity than conventional ones, and the content of alkali metal as an impurity is 50 ppm or less, more preferably 30 ppm or less, still more preferably 10 ppm or less. When the alkali metal content exceeds 50 ppm, the amount of ionic impurities eluted tends to increase.

  Here, the alkali metal content of PPS in the present invention is, for example, a value calculated from the amount of alkali metal in the ash that is a residue obtained by baking PPS using an electric furnace or the like. It can be quantified by analyzing by an atomic absorption method.

  The alkali metal refers to lithium, sodium, potassium, rubidium, cesium, and francium belonging to Group IA of the periodic table, but the PPS of the present invention preferably does not contain sodium as an alkali metal. When an alkali metal is contained, it tends to adversely affect the electrical characteristics and thermal characteristics of PPS. In addition, there is a possibility that the amount of metal eluted when PPS comes into contact with various solvents is increased, and when PPS contains lithium, this problem is increased because lithium is a metal that is easily eluted. By the way, among various metal species, compared to metal species other than alkali metals, such as alkaline earth metals and transition metals, alkali metals tend to have a strong influence on the electrical characteristics, thermal characteristics, and metal elution amount of PPS. is there. Therefore, it is estimated that the quality of the PPS hollow molded article for ultrapure water or ultrahigh purity solvent can be improved by controlling the alkali metal content within the above range among various metal species. Furthermore, among the alkali metals, in the polymerization of PPS, alkali metal sulfides typified by sodium sulfide are most commonly used, and by setting the sodium content within the above range, the quality of the PPS hollow molded body can be improved. I guess I can do it.

  The PPS hollow molded article of the present invention preferably contains substantially no halogen other than chlorine, that is, fluorine, bromine, iodine, or astatine. When the PPS of the present invention contains chlorine as a halogen, the PPS is stable in the temperature range in which it is normally used. Therefore, even if a small amount of chlorine is contained, there is little influence on the mechanical properties of the PPS. When contained, these unique properties tend to deteriorate the properties of PPS, such as electrical properties and residence stability. When the PPS of the present invention contains chlorine as a halogen, the preferred amount is 1% by weight or less, more preferably 0.5% by weight or less, and still more preferably 0.2% by weight or less. The amount of reactive gas generated is reduced, melt moldability and device corrosion can be reduced, and electrical characteristics and residence stability tend to be better.

  Another feature of the PPS hollow molded article of the present invention is that the amount of lactone type compound and / or aniline type compound generated when heated is remarkably small. Examples of the lactone type compound include β-propiolactone, β-butyrolactone, β-pentanolactone, β-hexanolactone, β-heptanolactone, β-octanolactone, β-nonalactone, and β-decalactone. , Γ-butyrolactone, γ-valerolactone, γ-pentanolactone, γ-hexanolactone, γ-heptanolactone, γ-octalactone, γ-nonalactone, γ-decalactone, δ-pentanolactone, δ-hexa Nolactone, δ-heptanolactone, δ-octanolactone, δ-nonalactone, δ-decalactone, etc. can be exemplified, and aniline type compounds include aniline, N-methylaniline, N, N-dimethylaniline, N -Ethylaniline, N-methyl-N-ethylaniline, 4-chloro-aniline, 4-chloro-N-methyl Niline, 4-chloro-N, N-dimethylaniline, 4-chloro-N-ethylaniline, 4-chloro-N-methyl-N-ethylaniline, 3-chloro-aniline, 3-chloro-N-methylaniline, Examples include 3-chloro-N, N-dimethylaniline, 3-chloro-N-ethylaniline, 3-chloro-N-methyl-N-ethylaniline and the like. The generation of lactone type compounds and / or aniline type compounds when heated causes factors such as foaming and die contamination during melt molding, which not only deteriorates melt moldability but also adversely affects the formation of defects in hollow molded products. The amount of lactone-type compound generated is preferably 500 ppm or less, more preferably 300 ppm, even more preferably, based on the weight of the PPS resin and PPS hollow molded body before heating. Is desirably 100 ppm or less, more preferably 50 ppm or less. Similarly, the amount of aniline type compound generated is preferably 300 ppm or less, more preferably 100 ppm, still more preferably 50 ppm or less, and even more preferably 30 ppm or less. In addition, as a method for evaluating the amount of lactone type compound and / or aniline type compound generated when PPS is heated, the gas generated when treated at 320 ° C. for 60 minutes in a non-oxidizing atmosphere is gas chromatographed. Divide and quantitate.

(2) Production method of PPS The weight average molecular weight (Mw) of the present invention is 10,000 or more, the dispersity represented by the weight average molecular weight / number average molecular weight (Mn) is 2.5 or less, and the alkali metal content is As a method for producing PPS for producing a polyphenylene sulfide hollow molded article characterized by being 50 ppm or less, a cyclic polyphenylene sulfide compound represented by the following general formula (1) is melt-heated to obtain a weight average molecular weight of 10 The PPS hollow molded article of the present invention having the above-described characteristics can be obtained by converting it into a polymer having a high degree of polymerization of 1,000 or more.

(3) Cyclic PPS Compound As the cyclic PPS compound of the present invention, a cyclic PPS compound represented by an integer of m = 4 to 20 represented by the following general formula (1) can be used, where m is A mixture of 4 to 20 may be used.

(M may be an integer of 4 to 20, m may be a mixture of 4 to 20)

  The repeating unit m in the above formula is an integer of 4 to 20, preferably 4 to 15, and more preferably 4 to 12.

  In addition, although the single-cycle cyclic PPS has a difference in easiness of crystallization, it is obtained as a crystal, so that the melting temperature becomes high, and therefore the temperature when converted to a high degree of polymerization tends to be high. Show. On the other hand, in the case of a mixture having different m, the melting temperature is lower than that of a single cyclic PPS, and the temperature at the time of conversion to a high molecular weight body can be reduced. Due to this feature, even if there is no polymerization initiator containing an alkali metal, the degree of polymerization proceeds rapidly, and side reactions at the time of increasing the degree of polymerization are further suppressed. It becomes possible to produce a PPS resin with a small amount of gas components.

For example, m = 6 cyclic PPS simple substance (cyclohexa (p-phenylene sulfide)) has a high melting point of 348 ° C., so that the cyclic product has a high molecular weight unless the heating temperature for melting is increased. There is a problem of not. Therefore, a method in which a cyclic PPS compound is dissolved in a solvent to be converted into a high molecular weight body, and a crystallized cyclic PPS simple substance is once melted at a melting point or higher, and then rapidly cooled to suppress crystallization and make it amorphous. Thereafter, a method of converting to a high degree of polymerization, or a method of setting the premelter to be equal to or higher than the melting point of the cyclic PPS alone, melting only the cyclic PPS alone in the premelter, and supplying it as a melt can be adopted.
Due to the characteristics of the cyclic PPS compound, the cyclic PPS compound used in the present invention is preferably a cyclic PPS compound having a different m from the viewpoint of easy high molecular weight and easy manufacture.
The content of cyclic PPS of m = 6 with respect to the cyclic PPS compound is preferably less than 50% by weight, more preferably less than 30% by weight (m = 6 cyclic PPS simple substance (weight) / (cyclic PPS compound (weight) × 100).

  The ratio of each different m in the cyclic PPS compound is not particularly limited, but in order to achieve the effects of the present invention, the cyclic PPS simple substance of m = 6 having the highest melting point and easy to crystallize among the cyclic PPS compounds. Is preferably less than 50% by weight, more preferably 30% by weight, particularly preferably less than 10% by weight (m = 6 cyclic PPS (weight) / (cyclic PPS mixture (weight) × 100). Here, the content of m = 6 cyclic PPS alone in the cyclic PPS mixture is attributed to the compound having a PPS structure when the cyclic PPS mixture is divided into components by high performance liquid chromatography equipped with a UV detector. The ratio of the peak area attributed to the cyclic PPS simple substance with m = 6 to the total peak area is as follows: Both are compounds having a PPS structure, such as a cyclic PPS compound or a linear PPS, and a compound having a structure other than phenylene sulfide as a part (for example, as a terminal structure) also belongs to the compound having a PPS structure here. In addition, the qualitative characteristics of each peak divided into components by this high performance liquid chromatography can be obtained by separating each peak by preparative liquid chromatography and performing an absorption spectrum or mass analysis in infrared spectroscopic analysis.

  Such a cyclic PPS compound can be obtained by obtaining a PPS mixture containing PPS and a cyclic PPS compound by a known PPS production method and then extracting the cyclic PPS compound from the PPS mixture. The manufacturing method will be described below.

(4) Production method of PPS mixture as raw material of cyclic PPS compound As a production method of PPS mixture, a known technique can be used, for example, polyhalogenated aromatic compound represented by at least p-dichlorobenzene, A mixture containing an alkali metal sulfide typified by sodium sulfide and an organic polar solvent typified by N-methyl-2-pyrrolidone is heated to prepare a reaction solution containing a polyphenylene sulfide mixture and an alkali metal halide, Examples thereof include a method of obtaining a PPS mixture (PPS and cyclic PPS compound) by treating the reaction solution with water or the like, and a method of obtaining a PPS mixture by oxidative polymerization of diphenyl disulfides or thiophenols. However, since the cyclic PPS compound generally contained in the PPS mixture generally obtained by these methods is as low as less than 5% by weight, in order to obtain a PPS mixture containing 5% by weight or more of the cyclic PPS compound, for example, polymerization of the PPS mixture is performed. In particular, a special method such as using a large amount of a polymerization solvent is necessary, and it is economically disadvantageous to obtain a large amount of PPS mixture efficiently by such a method, and it is difficult to establish industrially. .

  Examples of other methods for producing a PPS mixture include polyhalogenated aromatic compounds represented by at least p-dichlorobenzene, alkali metal sulfides represented by sodium sulfide, and N-methyl-2-pyrrolidone. At least granular PPS and a PPS mixture other than granular PPS, organic polar solvent, water, and alkali halide obtained by heating and polymerizing a mixture containing an organic polar solvent A preferred example is a method of obtaining a PPS mixture from a recovered slurry obtained when granular PPS is removed from a reaction solution containing a metal salt. Here, granular PPS refers to a PPS component that can be recovered with a standard sieve (80 mesh sieve) having an average aperture of 0.175 mm. The PPS mixture obtained by this method contains a large amount of low molecular weight PPS having a weight average molecular weight of 5,000 or less. For example, the properties such as mechanical properties are significantly inferior to those of the granular PPS. Has been conventionally recognized as being difficult and not worth industrial use. Therefore, the PPS mixture obtained by this method has usually been treated as industrial waste.

  As a result of detailed analysis of the PPS mixture other than the granular PPS, the present inventors include 10% by weight or more of the cyclic PPS represented by the formula (1) (m = 4 to 20). In particular, since these are obtained as a mixture of m = 4 to 20, it has been found preferable as a raw material for obtaining the cyclic PPS compound of the present invention. This is significant from the viewpoint of recovering a compound having an extremely high industrial utility value from what was conventionally regarded as industrial waste by the method of the present invention.

  As a method for recovering PPS from the recovered slurry, for example, at least 50% by weight or more of an organic polar solvent is removed from the recovered slurry, a residue is obtained, water is added thereto, and then an acid is added as desired. A method in which at least the residual organic polar solvent and the alkali metal halide are removed and the PPS mixture is separated and recovered, or a method in which the PPS mixture is precipitated from the recovered slurry and PPS is recovered as a solid component, for example, in the recovered slurry Examples thereof include a method of obtaining PPS as a solid component by a method such as decantation, centrifugation, and filtration, which are known solid-liquid separation methods, after PPS is precipitated by adding water.

(5) Preparation of cyclic PPS compound-containing solution In the present invention, a solution containing a cyclic PPS compound is prepared by bringing the PPS compound into contact with a solvent capable of dissolving the cyclic PPS compound (m = 4 to 20) described in formula (1). Prepare.

  The solvent used here is not particularly limited as long as it is a solvent capable of dissolving the cyclic PPS compound, but a solvent that dissolves the cyclic PPS compound but dissolves PPS in a dissolving environment is preferable, and a solvent that does not dissolve PPS. Is more preferable. The pressure of the reaction system when PPS is brought into contact with the solvent is preferably normal pressure or slight pressure, and particularly preferably normal pressure, and the reaction system of such pressure is advantageous in that the members of the reactor for constructing it are inexpensive. There is. From this point of view, it is desirable that the reaction system pressure avoid pressurizing conditions that require an expensive pressure vessel. As the solvent to be used, those which do not substantially cause undesirable side reactions such as decomposition and crosslinking of PPS and cyclic PPS compounds are preferable, and as a preferable solvent when the operation of bringing the PPS mixture into contact with the solvent is performed, for example, under atmospheric pressure reflux conditions. Are, for example, hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, cyclopentane, benzene, toluene, xylene, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene Halogen solvents such as 2,6-dichlorotoluene, ketone solvents such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone, acetophenone, diethyl ether, tetrahydrofuran, diisopropyl ether Examples include polar solvents such as ether solvents such as tellurium, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, trimethyl phosphoric acid, N, N-dimethylimidazolidinone, among others, benzene, toluene, Xylene, chloroform, bromoform, methylene chloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone, diethyl ether, Tetrahydrofuran, diisopropyl ether, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, trimethyl phosphoric acid, N, N-dimethylimidazolidinone are preferred, and toluene Xylene, chloroform, methylene chloride, acetone, diethyl ketone, methyl ethyl ketone, tetrahydrofuran may be cited more preferably.

  There is no particular limitation on the atmosphere when PPS is brought into contact with the solvent, but when PPS and the solvent are deteriorated by oxidation depending on conditions such as temperature and time at the time of contact, it is desirable to carry out in a non-oxidizing atmosphere. . Note that the non-oxidizing atmosphere is an atmosphere having a gas phase oxygen concentration of 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere such as nitrogen, helium, argon, or the like. Among these, a nitrogen atmosphere is particularly preferable from the viewpoints of economy and ease of handling.

  The temperature at which the PPS mixture is brought into contact with the solvent is not particularly limited, but generally, the higher the temperature, the more the dissolution of the cyclic PPS compound in the solvent tends to be promoted. As described above, since the PPS mixture is preferably contacted with the solvent under atmospheric pressure, the upper limit temperature is preferably set to the reflux condition temperature under atmospheric pressure of the solvent used. For example, 20 to 150 ° C. can be exemplified as a specific temperature range.

  The time for bringing the PPS mixture into contact with the solvent varies depending on the type of solvent used, the temperature, etc., and cannot be uniquely limited. For example, 1 minute to 50 hours can be exemplified, but if it is too short, the cyclic PPS is not sufficiently dissolved in the solvent If it is too long, dissolution in the solvent reaches a saturated state, and no further effect can be obtained.

  The method of bringing PPS into contact with a solvent is not particularly limited as long as a known general method is used. For example, a method of collecting a solution part after mixing a PPS mixture and a solvent and stirring as necessary, various filters Any method can be used, such as a method of dissolving the cyclic PPS in the solvent while simultaneously showering the solvent in the above PPS mixture, or a method based on the Soxhlet extraction principle. Although there is no restriction | limiting in particular in the usage-amount of the solvent at the time of making PPS and a solvent contact, For example, the range of 0.5-100 can be illustrated by the bath ratio with respect to PPS weight. When the bath ratio is too small, not only the mixing of the PPS mixture and the solvent becomes difficult, but also the cyclic PPS compound tends to be insufficiently dissolved in the solvent. A larger bath ratio is generally advantageous for dissolving a cyclic PPS compound in a solvent, but if it is too large, no further effect can be expected, and conversely an economic disadvantage due to an increase in the amount of solvent used may occur. . In the case where contact between the PPS and the solvent is repeated, a sufficient effect can often be obtained even with a small bath ratio. In addition, the Soxhlet extraction method, in principle, has the same effect as when PPS and the solvent are repeatedly contacted. In this case, a sufficient effect can often be obtained with a small bath ratio.

  When the solution in which the cyclic PPS compound is dissolved after the PPS is brought into contact with the solvent is obtained in the form of a solid-liquid slurry containing the remaining solid PPS, the solution part is recovered using a known solid-liquid separation method. . Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. For the solution thus separated, the solvent described later is removed. On the other hand, for the remaining solid component, when the cyclic PPS compound still remains, specifically when 0.05% by weight or more of the cyclic PPS compound remains on a weight basis, A cyclic PPS compound can be obtained with higher yield by repeatedly performing contact and solution recovery. Further, when the cyclic PPS compound hardly remains, specifically, when the residual cyclic PPS compound is less than 0.05% by weight, the remaining solid PPS is removed by removing the residual solvent. Can be suitably recycled as high-purity PPS.

(6) Removal of solvent from cyclic PPS compound solution In the present invention, the solvent is removed from the solution containing the cyclic PPS compound (m = 4 to 20) represented by the formula (1) obtained as described above. To obtain a cyclic PPS compound. The removal of the solvent can be exemplified by, for example, a method of heating and treating at normal pressure or less, or removal of the solvent using a film. However, from the viewpoint of obtaining a cyclic PPS compound with higher yield and efficiency. A method of removing the solvent by heating at a pressure lower than the pressure is preferred. The solution containing the cyclic PPS compound obtained as described above may contain a solid depending on the temperature. Since the solid in this case also belongs to the cyclic PPS compound, the solvent is removed when the solvent is removed. It is desirable to recover together with the soluble component, whereby the cyclic PPS compound can be obtained with good yield.

  In removing the solvent, it is desirable to remove at least 50% by weight, preferably 70% by weight or more, more preferably 90% by weight or more, and still more preferably 95% by weight or more. Although the temperature at which the solvent is removed by heating depends on the characteristics of the solvent used, it cannot be limited uniquely. However, the temperature can usually be selected from 20 to 150 ° C, preferably from 40 to 120 ° C. In addition, the pressure for removing the solvent is preferably normal pressure or lower, which makes it possible to remove the solvent at a lower temperature.

(7) Other post-treatments The cyclic PPS compounds obtained by the methods described in (4) to (6) are sufficiently high in purity and can be suitably used as cyclic PPS compounds of m = 4 to 20, Further, post-treatment described below can be additionally performed to obtain a higher-purity cyclic PPS compound and m = 6 cyclic PPS alone.

  The cyclic PPS compound obtained by the operations (4) to (6) may contain an impurity component contained in PPS depending on the characteristics of the solvent used. Impurities are dissolved in the cyclic PPS compound containing such a small amount of impurities, but the cyclic PPS compound is not dissolved, or the cyclic PPS compound is contacted with a second solvent in which the cyclic PPS compound is difficult to dissolve, thereby selectively removing the impurity component. Often it is possible to do.

  The pressure of the reaction system when the cyclic PPS compound is brought into contact with the second solvent is preferably normal pressure or slight pressure, and particularly preferably normal pressure, and the reaction system having such pressure is inexpensive to construct the members. There is an advantage. From this point of view, it is desirable that the reaction system pressure avoid pressurizing conditions that require an expensive pressure vessel. As the preferred solvent as the second solvent, those which do not substantially cause undesirable side reactions such as decomposition and crosslinking of the target cyclic PPS compound are preferable. For example, methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, Examples include alcohol-phenol solvents such as propylene glycol, phenol, cresol, and polyethylene glycol, and hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclohexane, and cyclopentane. Among them, methanol, ethanol, propanol, butanol, pen Tanol, ethylene glycol, propylene glycol, pentane, hexane, heptane, octane, cyclohexane, cyclopentane are preferred, methanol, ethanol, propanol, Ji glycol, pentane, hexane, heptane, octane, cyclohexane is particularly preferred. These solvents can be used as one kind or a mixture of two or more kinds.

  There is no particular limitation on the temperature at which the cyclic PPS compound is brought into contact with the second solvent, but the upper limit temperature is desirably the reflux condition temperature under normal pressure of the second solvent to be used. When using, 20-100 degreeC can be illustrated as a preferable temperature range, for example, More preferably, 25-80 degreeC can be illustrated.

  The time for which the cyclic PPS compound is brought into contact with the second solvent cannot be uniquely limited because it varies depending on the type of solvent used, the temperature, etc., but for example 1 minute to 50 hours can be exemplified, and if it is too short, impurities in the cyclic PPS compound In this case, the dissolution of the impurities in the second solvent reaches a saturated state, and no further effect can be obtained.

  As a method for bringing the cyclic PPS compound into contact with the second solvent, a method in which the solid cyclic PPS compound and the second solvent are mixed with stirring as necessary, and the second solvent is added to the cyclic PPS compound solid on various filters. A method of dissolving impurities in a second solvent at the same time as showering, a method using Soxhlet extraction of a solid cyclic PPS compound using a second solvent, a cyclic PPS compound slurry containing a solution-like cyclic PPS compound or a solvent For example, the cyclic PPS compound may be precipitated in the presence of the second solvent by bringing the compound into contact with the second solvent. In particular, the method of bringing the cyclic PPS compound slurry containing the solvent into contact with the second solvent is an effective method because the cyclic PPS compound obtained after the operation has high purity.

  After contacting the cyclic PPS compound with the second solvent, a slurry in which the cyclic PPS compound is precipitated in the second solvent is obtained, so that the solid cyclic PPS compound is recovered using a known solid-liquid separation method. To do. Examples of the solid-liquid separation method include separation by filtration, centrifugation, and decantation. If impurities still remain in the cyclic PPS compound obtained after the solid-liquid separation, the cyclic PPS compound and the second solvent can be contacted again to further remove the impurities.

(8) Characteristics of the cyclic PPS compound of the present invention The cyclic PPS compound thus obtained has m of 4 to 20 in the formula (1), and m = 4 to 20 represented by the formula (1). A cyclic PPS compound having m is preferable, and a cyclic PPS compound having a cyclic PPS content of m = 6 in the cyclic PPS compound is preferably less than 50% by weight.

As described above, m of the cyclic PPS compound of the present invention is m = 4 to 20, and m may be a mixture of 4 to 20, but as a cyclic PPS compound, m = 4 to 12 In the case where m is in this range, it has been found that the degree of polymerization by melting and heating of the cyclic PPS compound rapidly proceeds as described later.
In addition, although the possibility that the cyclic PPS compound whose m is 12 or more exists is high, it is difficult to qualitatively and quantitatively with the current analysis technique. This is because, as will be described later, it is difficult to distinguish between a linear PPS oligomer contained in a cyclic PPS compound and a cyclic PPS having m = 13 or more with the latest analysis technique at present. However, when a cyclic PPS compound of m = 4 to 20 is melted and heated, the degree of polymerization of the cyclic PPS compound rapidly increases, and the amount of volatile gas components in the resulting PPS resin is reduced. When the content of the single cyclic PPS of m = 6 is less than 50% by weight, these effects are further enhanced, so that a cyclic PPS compound having m of 13 or more is included within the range not impairing the effects of the present invention. It may be.

  Moreover, although the cyclic PPS compound obtained by the method as described in (4)-(7) is sufficiently high purity, depending on conditions, a linear PPS oligomer may contain as an impurity. Further, as described above, it is difficult to distinguish this linear PPS oligomer from a cyclic PPS compound having m = 13 or more with the latest analysis technique at present. The weight average molecular weight (Mw) of the oligomer component estimated to be a linear PPS oligomer varies depending on the production method of PPS used as the raw material of the cyclic PPS compound described in (4) above, but is usually 5000 or less. Yes, in some cases it is 2000 or less.

  The linear PPS oligomer remaining as an impurity in the cyclic PPS compound has poor thermal stability and increases the amount of volatile gas components as compared with the cyclic PPS compound. When these are contained in a large amount as impurities, there arises a problem that the conversion of the cyclic PPS compound into PPS by melting and heating becomes insufficient.

  Therefore, the amount of the linear PPS oligomer in the cyclic PPS compound obtained by the method described in (4) to (7) is preferably less than 50% by weight and less than 40% by weight with respect to the total cyclic PPS compound. More preferably, it is less than 30% by weight.

  The amount of linear PPS oligomer in the cyclic PPS compound at this time can be quantified by MALDI-TOF-MS as the total amount with the cyclic PPS compound of m = 13 or more according to the present analysis technique. It is.

  Further, as described in JP-A-10-77408, a cyclic PPS compound is Soxhlet extracted from a cross-linking type PPS, the extract is cooled, and the precipitated white solid is converted into m = No. 6 cyclic PPS is obtained with high purity (cyclohexa (p-phenylene sulfide). Although the recovery amount is small compared with the cross-linked PPS, it is the same from the linear PPS. In the same manner, it is possible to obtain a cyclic PPS simple substance with m = 6 with high purity by performing the extraction operation and recrystallizing.

  The cyclic PPS simple substance of m = 6 has an extremely stable needle-like crystal structure and is easy to crystallize. Therefore, while it is a ring suitable for the method of “recrystallization”, its stable needle-like crystal structure is Reflecting this, the melting point becomes as high as 348 ° C., so it is necessary to increase the melting heating temperature for increasing the degree of polymerization.

  When only cyclic PPS of m = 6 is used, a method of dissolving and supplying the cyclic PPS compound in a solvent that dissolves the cyclic PPS compound, and once crystallized cyclic PPS is melted above the melting point, it is rapidly cooled to suppress crystallization. A method of supplying amorphous powder, or a method in which the premelter is set to have a melting point higher than that of the cyclic PPS alone, and only the cyclic PPS is melted in the premelter and supplied as a melt. it can. In this way, when using cyclic PPS alone, it is necessary to increase the melting heating temperature for increasing the degree of polymerization, or as described above, once the cyclic PPS is melted once, the crystallization is suppressed to be amorphous. From the aspect of productivity and melt processability for increasing the degree of polymerization of cyclic PPS, it is necessary to melt only cyclic PPS in the premelter and supply it as a melt. The content of m = 6 cyclic PPS alone in the PPS compound is preferably less than 50% by weight, more preferably less than 40% by weight, still more preferably less than 30% by weight.

  The reason for this is currently interpreted as follows. That is, when the content of the cyclic PPS simple substance of m = 6 is reduced, there is an effect that the cyclic PPS simple substance does not act as a crystal nucleus. As a result, the cyclic PPS compound composed of a mixture of m = 4 or more It is considered that crystallization is suppressed and the melting point of the cyclic PPS compound is lowered, so that the cyclic PPS compound is easily melted, and as a result, the degree of polymerization can be easily increased by melting and heating.

  In addition, since cyclic monomers other than m = 6 are difficult to crystallize compared to m = 6, it has been difficult to obtain a monomer by a method called “recrystallization” (isolated by a method called recrystallization). Only the cyclic PPS simple substance of m = 6 is possible), and the inventors separated and recovered these monomers by a collection liquid chromatogram, and obtained the cyclic PPS simple substance (cyclotetra (p-phenylene sulfide), melting point of m = 4. 296 ° C.), m = 5 cyclopenta (p-phenylene sulfide) (melting point 257 ° C.), m = 7 cyclohepta (p-phenylene sulfide) (melting point 328 ° C.), m = 8 cycloocta (p-phenylene sulfide) (Melting point 305 ° C.).

  That is, according to the methods described in (4) to (7), the obtained cyclic PPS compound is a mixture having different m, and the content of the cyclic PPS simple substance of m = 6 is less than 50% by weight. . Depending on the conditions, it is possible to obtain a cyclic PPS having a content of m = 6 of less than 30% by weight, or even 10% by weight. The obtained cyclic PPS compound has a characteristic that the melting temperature is lower than that of a single cyclic PPS composed of m. For example, a cyclic PPS compound can be obtained by a simple method by using a high molecular weight polymer at a low melting heating temperature. It is possible to convert to

(9) Conversion of cyclic PPS compound to high polymerization degree The above-described PPS of the present invention is preferably produced by a method in which the cyclic PPS compound is melt-heated and converted to a high polymerization degree. The temperature of this melting and heating is preferably a temperature at which the cyclic PPS compound melts and is not particularly limited as long as it is such a temperature condition. If the heating temperature is lower than the melting temperature of the cyclic PPS compound, a long time tends to be required to increase the degree of polymerization of PPS. The temperature at which the cyclic PPS compound melts varies depending on the composition and purity of m present in the cyclic PPS compound as described above. For example, by analyzing the cyclic PPS compound with a differential scanning calorimeter, By grasping, it is possible to melt and heat above its melting temperature. However, if the temperature is too high, undesirable side reactions such as cross-linking reactions and decomposition reactions between PPS molecules generated by heating and between PPS and cyclic PPS compounds tend to occur, and the resulting PPS Therefore, it is desirable to avoid a temperature at which such an undesirable side reaction is remarkably generated. 180-400 degreeC can be illustrated as melt-heating temperature, Preferably it is 200-380 degreeC, More preferably, it is 250-360 degreeC.

  The time for performing the melting and heating cannot be uniformly defined because it varies depending on the composition of m in the cyclic PPS compound to be used, various properties such as the purity of the cyclic PPS compound, and the conditions such as the heating and melting temperature. It is preferable to set so that undesirable side reactions do not occur as much as possible. Examples of the heating and melting time include 0.05 to 100 hours, preferably 0.1 to 20 hours, and more preferably 0.1 to 10 hours. If it is less than 0.05 hours, the conversion of the cyclic PPS compound to PPS tends to be insufficient, and if it exceeds 100 hours, there is a high possibility that adverse effects on the properties of the resulting PPS due to undesirable side reactions will become apparent. Not only that, but there may be economic disadvantages.

  Conversion of the cyclic PPS compound to a high degree of polymerization by melting and heating is usually performed in the absence of a solvent, but can also be performed in the presence of a solvent. The solvent is not particularly limited as long as it does not substantially cause undesirable side reactions such as inhibition of conversion of the cyclic PPS compound to a high degree of polymerization by heating and decomposition or crosslinking of the produced PPS. Nitrogen-containing polar solvents such as methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, dimethyl ether, dipropyl ether , Ether solvents such as tetrahydrofuran, halogen solvents such as chloroform, methylene chloride, trichloroethylene, ethylene chloride, dichloroethane, tetrachloroethane, chlorobenzene, methanol, ethanol, propano Le, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, alcohol phenol based solvents such as polyethylene glycol, benzene, toluene, and aromatic hydrocarbon solvents such as xylene. It is also possible to use an inorganic compound such as carbon dioxide, nitrogen, or water as a solvent in a supercritical fluid state. These solvents can be used as one kind or a mixture of two or more kinds.

  The conversion of the cyclic PPS compound into a high degree of polymerization by heating may be performed in a mold for producing a molded product, as well as by a method using a normal polymerization reaction apparatus, an extruder, Any apparatus equipped with a heating mechanism, such as a melt kneader, can be used without particular limitation, and known methods such as a batch method and a continuous method can be employed.

  The atmosphere during the conversion of the cyclic PPS compound to a high degree of polymerization by heating is preferably a non-oxidizing atmosphere, and is also preferably performed under reduced pressure. Moreover, when it carries out under pressure reduction conditions, it is preferable to make it the pressure reduction conditions after making the atmosphere in a reaction system once non-oxidizing atmosphere. This tends to suppress the occurrence of undesirable side reactions such as crosslinking reaction and decomposition reaction during conversion to a high degree of polymerization by overheating. The non-oxidizing atmosphere is an atmosphere in which the oxygen concentration in the gas phase in contact with the cyclic PPS compound is 5% by volume or less, preferably 2% by volume or less, and more preferably substantially free of oxygen, that is, nitrogen, helium, argon, etc. In particular, a nitrogen atmosphere is preferable from the viewpoint of economy and ease of handling. The reduced pressure condition means that the reaction system is lower than atmospheric pressure, and the upper limit is preferably 50 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less. An example of the lower limit is 0.1 kPa or more, and 0.2 kPa or more is more preferable. When the decompression condition exceeds the preferred upper limit, an undesirable side reaction such as a crosslinking reaction tends to occur. On the other hand, when the decompression condition is less than the preferred lower limit, the cyclic PPS compound having a low molecular weight contained in the cyclic PPS compound volatilizes depending on the reaction temperature. It tends to be easy to do.

  The PPS resin thus obtained is excellent in heat resistance, chemical resistance, flame retardancy, electrical properties and mechanical properties, and is suitably used for melt spinning.

  In the PPS hollow molded article of the present invention, other resins can be added in an amount of 40% by weight or less as long as the effects of the present invention are not impaired. For example, the flexibility and impact resistance can be further improved by adding a small amount of a highly flexible thermoplastic resin. In particular, addition of 5% 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, modified polyphenylene ether resins, polysulfone resins, polyketone resins, polyethers. Examples include imide resins, polyarylate resins, liquid crystal polymers, polyether sulfone resins, polyether ketone resins, polythioether ketone resins, polyether ether ketone resins, polyimide resins, polyamideimide resins, and tetrafluoropolyethylene resins. 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. Any of the above compounds may be added in an amount of 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less of the total composition.

  Furthermore, although not an essential component, the PPS resin tubular body of the present invention can be used by blending an inorganic filler as long as the effects of the present invention are not impaired. Specific examples of such inorganic fillers include glass fiber, carbon fiber, carbon nanotube, carbon nanohorn, potassium titanate whisker, zinc oxide whisker, calcium carbonate whisker, wollastonite whisker, aluminum borate whisker, aramid fiber, alumina fiber, silicon carbide fiber. , Ceramic filler, asbestos fiber, stone fiber, metal fiber, etc., or fullerene, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, asbestos, alumina Silicates such as silicates, metal compounds such as silicon oxide, magnesium oxide, alumina, zirconium oxide, titanium oxide and iron oxide, carbonates such as calcium carbonate, magnesium carbonate and dolomite, sulfuric acid Sulfates such as lucium and barium sulfate, hydroxides such as calcium hydroxide, magnesium hydroxide and aluminum hydroxide, glass beads, glass flakes, glass powder, ceramic beads, boron nitride, silicon carbide, carbon black and silica, graphite Non-fibrous fillers such as glass fiber, silica, and calcium carbonate are preferable, and calcium carbonate and silica are particularly preferable from the viewpoint of the effects of the anticorrosive material and the lubricant. These inorganic fillers may be hollow, and two or more kinds may be used in combination. Further, these inorganic fillers may be used after being pretreated 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 not particularly limited, but is usually in the range of 0.0001 to 800 parts by weight with respect to 100 parts by weight of PPS.

  In the present invention, the strength can be further improved by blending a coupling agent such as organic silane. The amount of the organic silane is 0.1 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of PPS.

  As described above, when a PPS resin composition is prepared by blending another resin or blending an additive for the purpose of modifying the PPS hollow molded body, the cyclic PPS compound is melted and heated to obtain a high degree of polymerization. The PPS resin obtained by increasing the degree of polymerization of the cyclic PPS compound by melting and heating can be once pelletized and then melt-kneaded with these compounding agents again.

  As the melt kneading method, a method of uniformly melt kneading with a single screw or twin screw extruder is preferable, and a method of melt kneading using a twin screw extruder is particularly preferable.

  The method for preparing the PPS resin composition at this time is not particularly limited, but the mixture of raw materials is supplied to a commonly known melt mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, a mixing roll, and the like. A method of kneading at a temperature of 380 ° C. can be mentioned as an example. In addition, there is no particular limitation on the mixing order of the raw materials, either a cyclic PPS compound and a PPS resin, and if necessary, dry blending other additives at once and then melt-kneading by the above-described method, etc. A typical method is one of PPS compound and PPS resin and, if necessary, two or three of the other additives, dry blended and melt kneaded, and then the remaining one or two are melt kneaded. It is.

  Examples of the shape of the hollow molded body in the present invention include tubular bodies such as tubes and pipes, containers, tank-shaped bodies, and the like.

  There are no particular restrictions on the method for producing such a hollow molded body, but a cutting method from a lump, round bar, square bar, extrusion molding method using a die for molding a tube or pipe, direct blow molding method, accumulator Various blow molding methods, such as a blow molding method, a multidimensional blow molding method, an injection blow molding method, and a vacuum blow molding method, may be mentioned. Also, a method of combining injection molded bodies having a shape such as a box shape or a semicircular shape, for example, a die slide injection method, a die rotating injection method, an injection welding method, or once taken out after injection molding, vibration welding of two or more molded bodies, Various methods such as hot plate welding, laser welding, and bonding with an adhesive can be employed. Further, these PPS hollow molded articles can be applied to lamination with other resins, metal lining, and the like in order to impart properties such as flexibility and rigidity while taking advantage of their excellent barrier properties and low elution properties. Among them, the PPS resin used in the present invention can be highly polymerized, and thus is particularly suitably used for extrusion molding methods and blow molding methods using dies for forming tubes and pipes.

  The hollow molded body obtained in the present invention can be used as a high-strength hollow molded body, a heat-resistant hollow molded body, a chemical-resistant hollow molded body, a low ionic impurity hollow molded body, a low organic matter elution hollow molded body, Taking advantage of these features, ultrapure water and ultrapure solvent pipes and tubes in the semiconductor industry, tubes, containers and factory piping / container applications, automotive piping / container applications, and consumer use, such as chlorofluorocarbon and supercritical dioxide. Although it can use preferably for uses, such as piping for carbon refrigerant, a tube, and a container, it is not limited to these uses.

  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.

<Molecular weight measurement>
The molecular weights of the PPS resin and the hollow molded article were calculated in terms of polystyrene by gel permeation chromatography (GPC) which is a kind of size exclusion chromatography (SEC). The measurement conditions for GPC are shown below.
Equipment: Senshu Science SSC-7100
Column name: Senshu Science GPC3506
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature: 250 ° C
Pump bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection amount: 300 μL (slurry: about 0.2% by weight)

<Melting point of cyclic PPS compound>
The thermal properties of the polymer obtained using a Perkin Elmer DSC7 were measured. Under the following measurement conditions, the crystallization temperature Tc was 1st Run, and the melting point Tm was 2nd Run.
First Run
・ 50 ° C x 1 minute hold ・ Temperature increase from 50 ° C to 320 ° C, temperature increase rate 20 ° C / min ・ 320 ° C × 1 minute hold ・ Temperature decrease from 320 ° C to 100 ° C, temperature decrease rate 20 ° C / min
・ 100 ℃ × 1 minute hold ・ Raise the temperature from 100 ℃ to 320 ℃, Heating rate 20 ℃ / min (The melting peak temperature at this time is Tm)

<Quantification of alkali metal content>
Quantification of the alkali metal content in the PPS resin and the hollow molded article was performed as follows.
(A) The sample was weighed in a quartz crucible and incinerated using an electric furnace.
(B) After the ashed product was dissolved with concentrated nitric acid, the volume was adjusted to a constant volume with diluted nitric acid.
(C) The obtained constant volume solution was subjected to ICP gravimetric analysis (apparatus; 4500 manufactured by Agilent) and ICP emission spectroscopic analysis (apparatus; Optima 4300DV manufactured by PerkinElmer).

<Quantitative determination of halogen content>
The amount of halogen in the PPS hollow molded article was determined by the following method.
(A) The sample was burned in a flask filled with oxygen.
(B) Absorbing liquid was prepared by absorbing combustion gas into the solution.
(C) A part of the absorbing solution was analyzed by ion chromatography (apparatus; DX320 manufactured by Dionex), and the halogen concentration was quantified.

<Analysis of gas components generated during heating of PPS>
The components generated when the PPS resin and the hollow molded article were heated were quantified by the following method.

(A) Collection of gas generated during heating Approximately 10 mg of PPS resin and a hollow molded product are heated at 320 ° C. under a nitrogen stream (50 ml / min) for 60 minutes, and the generated gas component is used for heating and desorption for atmospheric collection. Collected in a tube carbtrap 400.

(B) Analysis of gas component The gas component collected in the tube was thermally desorbed by raising the temperature from room temperature to 280 ° C. for 5 minutes using a thermal desorption device TDU (manufactured by Supelco). The thermally desorbed component was divided into components using gas chromatography, and γ-butyrolactone and 4-chloro-N-methylaniline in the gas were quantified.

<Elution evaluation of organic substances>
Put ultrapure water (100 g) in a container made of “Teflon (registered trademark)” and immerse a strip-shaped sample (100 g) obtained by cutting a blow-molded product into 5 mm × 10 mm in this ultrapure water, and seal it. Place in a gear oven at ℃ for 7 days. Thereafter, the total organic carbon content (TOC) of ultrapure water in a container made of “Teflon (registered trademark)” is measured to evaluate the elution of the organic substance.

  The total organic carbon content of ultrapure water used for this measurement was 40 μg / l. Further, in order to know the elution amount of the organic substance from the “Teflon (registered trademark)” container, the total organic carbon amount of ultrapure water was measured (blank measurement value) in the case where the pellet sample was not immersed. The total organic carbon content was 120 μg / l.

<Elution of metallic Na ions>
Put ultrapure water (100 g) in a container made of “Teflon (registered trademark)” and immerse a strip-shaped sample (100 g) obtained by cutting a blow-molded product into 5 mm × 10 mm in this ultrapure water, and seal it. Place in a gear oven at ℃ for 7 days. Then, the elution property of the metal ionic substance is evaluated by measuring the metal Na ion of ultrapure water in the container made of “Teflon (registered trademark)”.

  The amount of metallic Na ions in ultrapure water used for this measurement was less than the ppb order. In addition, in order to know the elution amount of metal Na ions from the “Teflon (registered trademark)” container, the amount of metal Na ions in ultrapure water was measured for the case where the above pellets were not immersed (blank measurement value). The amount of metal Na ions was 1 ppb or less.

  The following examples were examined using the reagents described below.

[Reference Example 1] (Example of production of PPS mixture as a raw material for cyclic PPS)
A production example of a PPS mixture as a raw material for the cyclic PPS described in the text (3) will be described below.

<Preparation of PPS mixture>
In a 1000 L autoclave with a stirrer, 42.7% sodium hydrosulfide 82.7 kg (700 mol), 96% sodium hydroxide 29.6 kg (710 mol), N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) In some cases, 114.4 kg (1156 mol) of sodium acetate, 17.2 kg (210 mol) of sodium acetate, and 100 kg of ion-exchanged water are gradually heated to about 240 ° C. over about 3 hours while flowing nitrogen at normal pressure. After distilling 143 kg of water and 2.8 kg of NMP through the rectification tower, the reaction vessel was cooled to 160 ° C. In addition, 0.02 mol of hydrogen sulfide per 1 mol of the sulfur component charged during this liquid removal operation was scattered out of the system.

  Next, 103 kg (703 mol) of p-dichlorobenzene and 90 kg (910 mol) of NMP were added, and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, the temperature was raised to 270 ° C. at a rate of 0.6 ° C./min and held at this temperature for 140 minutes. While 12.6 kg (700 mol) of water was injected over 15 minutes, it was cooled to 250 ° C. at a rate of 1.3 ° C./min. Thereafter, the slurry was cooled to 220 ° C. at a rate of 0.4 ° C./min, and then rapidly cooled to near room temperature to obtain a slurry (A). This slurry (A) was diluted with 200 kg of NMP to obtain a slurry (B).

  200 kg of the slurry (B) heated to 80 ° C. is filtered with a sieve (80 mesh, opening 0.175 mm) at a 50 kg / 1 batch scale, and about 150 kg of the slurry (C) is used as a filtrate component, and the slurry is used as a mesh-on component. 50 kg of granular PPS resin (crude PPS resin (D)) was obtained.

150 kg of the obtained slurry (C) was charged into a devolatilizer at 50 kg / 1 batch and replaced with nitrogen, and treated at 100 to 150 ° C. under reduced pressure for 1.5 hours, and then 150 ° C. and 1 ° C. in a vacuum dryer. Time treatment gave a solid. After adding 200 kg of ion-exchanged water (1.2 times the amount of slurry (C)) to this solid, it was stirred at 70 ° C. for 30 minutes to make a slurry again. This slurry was subjected to vacuum suction filtration with a filter having an opening of 10 to 16 μm. To the obtained white cake, 200 kg of ion-exchanged water was added and stirred at 70 ° C. for 30 minutes to make a slurry again. Similarly, after suction filtration, vacuum drying was performed at 70 ° C. for 5 hours to obtain 2 kg of a PPS mixture.
A production example of a cyclic PPS mixture using the PPS mixture obtained here will be described below.

[Reference Example 2] (Production of cyclic PPS compound)
Using 2 kg of the PPS mixture obtained by the method of Reference Example 1 and 50 kg of chloroform as a solvent, the PPS mixture and the solvent were contacted by an extraction method at a bath temperature of about 80 ° C. for 3 hours to obtain an extract. The obtained extract was in the form of a slurry partially containing solid components at room temperature. Chloroform was distilled off from the extract slurry using an evaporator and then treated at 70 ° C. for 3 hours in a vacuum dryer to obtain 840 g of a solid (42% yield based on the PPS mixture).

  The solid thus obtained was confirmed to be a compound having a phenylene sulfide skeleton from an absorption spectrum in infrared spectroscopic analysis (apparatus; FTIR-8100A manufactured by Shimadzu Corporation). In addition, mass spectrum analysis (device: Hitachi M-1200H) of components separated from high performance liquid chromatography (device; Shimadzu LC-10, column; C18, detector; photodiode array), MALDI-TOF -From the molecular weight information by MS and GPC, this solid is a mixture mainly composed of cyclic PPS having 4 to 12 repeating units shown in Table 1, and the weight fraction of cyclic PPS is about 87% and 13% is straight. The chain PPS oligomer and cyclic PPS of m = 13 or more (Mw = 2000), Tm = 226 ° C.

  According to the present invention, it was found that a high-purity cyclic PPS mixture containing about 87% by weight of cyclic PPS can be obtained in high yield.

[Example 1]
The cyclic PPS compound obtained in Reference Example 2 was charged into a 1 L autoclave equipped with a stirrer and replaced with nitrogen. The autoclave was heated to 300 ° C. in 1 hour. When the cyclic PPS compound was melted in the course of temperature increase, the rotation of the stirrer was started, and the mixture was melted and heated for 60 minutes with stirring at a rotational speed of 10 rpm. Thereafter, the polymer was taken out in a gut shape from the discharge port by nitrogen pressure, and the gut was pelletized. The obtained infrared spectrum of the slightly blackish product was found to have a PPS structure. The product was completely dissolved in 1-chloronaphthalene at 210 ° C. A series of evaluation results are summarized in Table 2 below.

  (1) Using the obtained PPS resin pellets, the molding apparatus has an extruder, a die that molds the resin discharged from the extruder into a tube shape, a sizing die that cools the tube and controls its dimensions, and A thing consisting of a take-up machine was used. The obtained tube had an outer diameter of 8 mm and an inner diameter of 6 mm, and the flatness of the inner and outer surfaces was also good.

  (2) Using the obtained resin pellets, supplying to a blow molding machine equipped with a 20 mmφ extruder, extruding at a cylinder temperature of 320 ° C., forming a parison with an outer diameter of 10 mm and a wall thickness of 2 mm, and then in the mold Then, air was blown in to form a regular quadrangular prism container having a side of 15 mm and a height of 50 mm. The obtained molded article had little thickness unevenness and good molding appearance.

[Example 2]
The extruder temperature was set to 350 ° C., the average residence time was set to 10 minutes, the degree of polymerization of the cyclic PPS was increased in the excluder, and the polymer melt was supplied to the blow molding machine via a gear pump. The obtained molded article had little thickness unevenness and good molding appearance.

[Comparative Example 1] <Preparation 1 of PPS according to the prior art>
About 20 liters of NMP was added to 20 kg of the crude PPS resin (D) obtained in Reference Example 1, washed at 85 ° C. for 30 minutes, and filtered through a sieve (80 mesh, opening 0.175 mm). The operation of diluting the obtained solid with 50 liters of ion exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh sieve to collect the solid was repeated 5 times in total. The solid thus obtained was dried with hot air at 130 ° C. to obtain a dried polymer. The absorption spectrum of the obtained polymer by infrared spectroscopic analysis was consistent with the absorption of the PPS mixture obtained in Reference Example 1.

  A series of evaluation results are summarized in Table 2. As a result of GPC measurement of the obtained PPS resin, it was found that the obtained PPS had a weight average molecular weight of 59600 and a dispersity of 3.8. Further, as a result of elemental analysis, the Na content was 1040 ppm. Furthermore, as a result of analyzing the generated gas component during heating of the obtained PPS, 618 ppm of γ-butyrolactone and 416 ppm of 4-chloro-N-methylaniline were detected with respect to the weight of PPS before heating. Here, alkali metals other than Na and halogens other than chlorine were not detected.

  (1) The resin pellets are supplied to a blow molding machine equipped with a 20 mmφ extruder, extruded at a cylinder temperature of 320 ° C., and after forming a parison having an outer diameter of 10 mm and a wall thickness of 2 mm, air is blown in the mold. A regular quadrangular prism-shaped container having a blowing side of 15 mm and a height of 50 mm was formed. The obtained molded product showed unevenness of about 10% in thickness at the top and bottom. The molding appearance was good.

[Comparative Example 2] <Preparation 2 of PPS by the prior art>
About 20 liters of NMP was added to 20 kg of the crude PPS resin obtained in Reference Example 1, washed at 85 ° C. for 30 minutes, and filtered through a sieve (80 mesh, opening 0.175 mm). The operation of diluting the obtained solid with 100 liters of ion exchanged water, stirring at 70 ° C. for 30 minutes, and filtering through an 80 mesh sieve to collect the solid was repeated a total of 3 times. Next, the obtained solid was diluted with 100 liters of ion-exchanged water to form a slurry, and then 48 g of acetic acid was added to make the slurry acidic, followed by stirring and washing at 70 ° C. for 30 minutes, and filtration through an 80 mesh sieve. The obtained solid was again diluted with 100 liters of ion exchange water, stirred at 70 ° C. for 30 minutes, and then filtered through an 80 mesh sieve. The solid thus obtained was dried with hot air at 130 ° C. to obtain a dried polymer.

  A series of evaluation results are summarized in Table 2 below. As a result of GPC measurement of the obtained PPS, the weight average molecular weight of the obtained PPS was 59700, and the degree of dispersion was 3.8, which was not different from Comparative Example 1. Further, as a result of elemental analysis, the Na content was 170 ppm. Furthermore, as a result of analyzing the generated gas component during heating of the obtained PPS, 1350 ppm of γ-butyrolactone and 382 ppm of 4-chloro-N-methylaniline were detected with respect to the weight of PPS before heating. Here, alkali metals other than Na and halogens other than chlorine were not detected.

  (1) The resin pellets are supplied to a blow molding machine equipped with a 20 mmφ extruder, extruded at a cylinder temperature of 320 ° C., and after forming a parison having an outer diameter of 10 mm and a wall thickness of 2 mm, air is blown in the mold. A regular quadrangular prism-shaped container having a blowing side of 15 mm and a height of 50 mm was formed. The obtained molded product showed unevenness of about 10% in thickness at the top and bottom. As for the molded appearance, the inner surface was colored by gas burning.

[Comparative Example 3] <Preparation 3 of PPS mixture according to prior art>
Here, the result at the time of manufacturing PPS using the PPS mixture which consists of cyclic | annular PPS obtained by the manufacturing method of PPS currently disclosed by the nonpatent literature 1 and a linear PPS oligomer is shown.

  In a 500 liter autoclave equipped with a stirrer, 6000 g (2.5 mol) of sodium sulfide nonahydrate, 52 g (1.25 mol) of 96% sodium hydroxide, 256 kg (2590 mol) of NMP and 3770 g of p-dichlorobenzene (25.25 mol). 5 mol) was charged and the reaction vessel was sealed under nitrogen gas. While stirring at 240 rpm, heating was performed from room temperature to 200 ° C. over about 2 hours, and then the temperature was increased to 220 ° C. at a rate of 1.0 ° C./min and held at this temperature for 10 hours. Thereafter, it was cooled to around room temperature to obtain slurry (E). 100 kg of this slurry (E) was diluted with 400 kg of ion exchange water, stirred at 70 ° C. for 30 minutes, and then filtered using a glass filter with an average pore size of 10 to 16 μm. The obtained solid component was dispersed in 100 kg of ion-exchanged water and stirred at 70 ° C. for 30 minutes, followed by filtration in the same manner. Next, the solid component was dispersed in 100 kg of a 0.5% acetic acid aqueous solution and stirred at 70 ° C. for 30 minutes, followed by filtration in the same manner. The obtained solid component was dispersed again in 100 kg of ion-exchanged water and stirred at 70 ° C. for 30 minutes, followed by filtration in the same manner. The obtained water-containing cake was dried overnight at 70 ° C. in a vacuum dryer to obtain 740 g of a dried cake.

  The total dry cake thus obtained was extracted with 15 kg of tetrahydrofuran for 3 hours. Tetrahydrofuran was distilled off from the resulting extract. 15 kg of acetone was added to the solid thus obtained and stirred, followed by suction filtration with a glass filter having an opening of 10 to 16 μm to obtain a white cake. This was vacuum-dried at 70 ° C. for 3 hours to obtain a white powder. The white powder thus obtained was confirmed to be a compound having a PPS skeleton from an absorption spectrum in infrared spectroscopic analysis (apparatus; FTIR-8100A manufactured by Shimadzu Corporation). In addition, mass spectrum analysis (device: Hitachi M-1200H) of components separated from high performance liquid chromatography (device; Shimadzu LC-10, column; C18, detector; photodiode array), MALDI-TOF -From the molecular weight information by MS and GPC, this solid is a mixture mainly composed of cyclic PPS having 4 to 12 repeating units shown in Table 3, and the weight fraction of cyclic PPS is about 40% and 60% It was found that the chain PPS oligomer and cyclic PPS with m = 13 or more (Mw = 1500), Tm = 245 ° C.

  An attempt was made to increase the degree of polymerization of PPS in the same manner as in Example 1 except that the obtained white powder, that is, a PPS mixture containing about 40% by weight of cyclic PPS and 60% by weight of linear PPS oligomer was used as a raw material. A series of results are summarized in Table 2.

  The resulting product was a brownish brittle mass. The infrared spectrum of the product was found to be PPS. The product was completely dissolved in 1-chloronaphthalene at 210 ° C., but the solution was colored brown. The Na content was 8 ppm. Furthermore, as a result of analyzing the generated gas component during heating of the obtained PPS, lactone type compounds and aniline type compounds could not be detected. Here, alkali metals other than Na and halogens other than chlorine were not detected. As a result of GPC measurement, the weight average molecular weight of the obtained PPS was 3200, and the degree of dispersion was 2.1. Thus, a high molecular weight PPS could not be obtained, and blow molding was attempted in the same manner as in Example 1. Due to the molecular weight, the parison was drawn down, and it was difficult to obtain a PPS blow molded article.

  As described above, the molecular weight distribution of the PPS resin is narrower than that of the conventional PPS resin, and the alkali metal content in the PPS resin is further reduced, so that the amount of ionic impurities and organic substances eluted is extremely small. It has become possible to provide a hollow molded body and a method for producing the same.

Claims (8)

It is composed of polyphenylene sulfide having a weight average molecular weight (Mw) of 10,000 or more, a dispersity represented by weight average molecular weight / number average molecular weight (Mn) of 2.5 or less, and an alkali metal content of 50 ppm or less. A featured polyphenylene sulfide hollow molded body. 2. The polyphenylene sulfide hollow molded article according to claim 1, wherein the alkali metal in the polyphenylene sulfide is sodium. The lactone type compound in the generated gas component when the polyphenylene sulfide hollow molded body is heated is 500 ppm or less based on the weight of the polyphenylene sulfide, and the aniline type compound is 300 ppm or less based on the weight of the polyphenylene sulfide. Or the polyphenylene sulfide hollow molded object of 2. The polyphenylene sulfide according to any one of claims 1 to 3, wherein the polyphenylene sulfide is a polyphenylene sulfide obtained by melting and heating a cyclic polyphenylene sulfide mixture represented by the following general formula (1). Sulfide hollow molded body.

(M may be an integer of 4 to 20, m may be a mixture of 4 to 20) The polyphenylene sulfide hollow molded body according to any one of claims 1 to 4, wherein the polyphenylene sulfide hollow molded body is formed by extrusion molding or blow molding. The polyphenylene sulfide hollow molded body according to claim 5, wherein the polyphenylene sulfide hollow molded body is a tubular body formed by extrusion molding. A polyphenylene sulfide hollow molded body characterized in that a polyphenylene sulfide obtained by melting and heating a cyclic polyphenylene sulfide mixture represented by the following general formula (1) is continuously melt-molded while maintaining a melt state. Manufacturing method.

(M may be an integer of 4 to 20, m may be a mixture of 4 to 20) The method for producing a polyphenylene sulfide hollow molded article according to claim 7, wherein the melt molding is extrusion molding or blow molding.