JP3090459B2 - Method for producing polyarylene sulfide resin composition - Google Patents

Description

The present invention relates to a method for producing a polyarylene sulfide resin composition containing a polyarylene sulfide resin and a fluorine-based resin, and particularly relates to a polyarylene sulfide resin and a fluorine-containing resin. Good compatibility with base resin, heat resistance,
The present invention relates to a method for producing a polyarylene sulfide resin composition having excellent chemical resistance, low friction properties, abrasion resistance and the like.

[Conventional technology]

Polyarylene sulfide resin such as polyphenylene sulfide resin is excellent in general mechanical properties and heat resistance, but when used for sliding parts materials, for example, gears, bearings, seal materials, etc. There is not enough wear resistance.

On the other hand, fluorine-based resins such as polytetrafluoroethylene and tetrafluoroethylene-perfluoroalkylvinyl ether copolymer are known as materials having chemical resistance, non-adhesiveness, and heat resistance. There is a problem that the wear resistance is not sufficient.

Such a polyarylene sulfide resin, polytetrafluoroethylene or tetrafluoroethylene-
Various proposals have been made to impart slidability by mixing with a perfluoroalkyl vinyl ether copolymer.

Japanese Patent Application Laid-Open No. 52-129761 discloses a lubricating member required by adding graphite, polytetrafluoroethylene and a lubricating oil to a polyphenylene sulfide resin.

JP-A-55-45704 discloses a composition containing a low-crystalline thermoplastic resin composition, carbon fiber, graphite and a fluororesin in a polyphenylene sulfide resin.

JP-A-60-228558 discloses a composition containing polytetrafluoroethylene, molybdenum disulfide, an inorganic filler, and a fibrous reinforcing material in a polyphenylene sulfide resin.

Further, JP-A-61-266451 discloses (a) at least one resin comprising a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin, a tetrafluoroethylene-hexafluoropropylene copolymer resin and a fluoroethylene propylene ether resin; A composition for a sliding member comprising a sulfide resin is disclosed.

[Problems to be solved by the invention]

However, in each of the above-mentioned compositions, during the production thereof,
A fluorine-based resin such as polytetrafluoroethylene or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer is blended with a polyphenylene sulfide resin in the form of a powder, and kneaded at a temperature equal to or higher than the melting point thereof. Powders of ethylene and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers aggregate to form a macroscopic self-layer, and there is a problem that compatibility is not good.

On the other hand, by mixing powder of polyphenylene sulfide resin and fluororesin such as polytetrafluoroethylene,
Although there is a method of molding with a ram extruder or the like, or a compression molding, there is a state where the fluorine-based resin is not necessarily uniformly dispersed in the polyphenylene sulfide resin.

As described above, a composition containing a polyarylene sulfide resin such as a conventional polyphenylene sulfide resin and a polytetrafluoroethylene or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, because both have no affinity There was no one having good compatibility that could be uniformly dispersed.

Accordingly, an object of the present invention is to disperse polytetrafluoroethylene or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer or the like in a polyarylene sulfide resin finely and have good compatibility, heat resistance, chemical resistance, and low heat resistance. An object of the present invention is to provide a method for producing a polyarylene sulfide resin composition having excellent friction and abrasion resistance.

[Means for solving the problem]

As a result of intensive research in view of the above objects, the present inventors have found that a resin composition containing a polyarylene sulfide resin and a polytetrafluoroethylene, a fluororesin such as a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, Polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and the like, as compatibilizer tetrafluoroethylene-olefin copolymer, polyvinylidene fluoride,
One or two or more selected from vinylidene fluoride copolymers are blended, melt-kneaded in advance, and the resulting mixture is melt-kneaded with a polyarylene sulfide resin at a predetermined temperature, thereby causing the above problem. The inventors have found that a composition in which the above has been solved can be obtained, and have reached the present invention.

That is, the method for producing a polyarylene sulfide resin composition of the present invention comprises: (a) 5 to 30 parts by volume of a copolymer containing polytetrafluoroethylene and / or tetrafluoroethylene and a fluorovinyl monomer; One or more selected from a fluoroethylene-olefin copolymer, polyvinylidene fluoride, and vinylidene fluoride copolymer, and 95 to 70 parts by volume at a temperature not lower than the melting points of (a) and (b). 5 to 30 parts by volume of the kneaded product obtained by melt-kneading and (c) 95 to 70 parts by volume of a polyarylene sulfide resin are mixed with each other at the melting points of (b) and (c) or higher, It is characterized by being melt-kneaded at a temperature lower than the melting point.

 Hereinafter, the present invention will be described in detail.

In the present invention, the polytetrafluoroethylene of (a) is a polymer obtained by polymerizing tetrafluoroethylene (CF ₂ = CF ₂ ), and is represented by a general formula: CF ₂ -CF _{2 n.} is there. The polytetrafluoroethylene usually has a melt viscosity of 10 ¹¹ to 10 ¹³ poise (380 ° C.), and its melting point is 327 ° C. Such polytetrafluoroethylene is known under the trade name of "Teflon" of DuPont. As a commercially available powder, for example, "Lubron L-5" (trade name, manufactured by Daikin Industries, Ltd.) ) Teflon TE914J (trade name) manufactured by Mitsui Dupont Fluorochemicals Co., Ltd.

Further, in the present invention, the fluorovinyl monomer copolymerized with tetrafluoroethylene is one in which a hydrogen atom of a vinyl group is substituted by fluorine, and has a fluorinated substituent. Examples of the fluorovinyl monomer include perfluoroalkyl vinyl ether.

Examples of the copolymer containing tetrafluoroethylene and a fluorovinyl monomer include, for example, a binary copolymer such as a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (PFA), and tetrafluoroethylene and a perfluoroalkyl vinyl ether. And a terpolymer (EPE) of hexafluoropropylene and the like.

The tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) has the general formula: (In the formula, R _f represents a perfluoro substituent such as CF ₃ , C ₂ F ₅ , and C ₃ F _7. )

The above tetrafluoroethylene-perfluoroalkylvinyl ether copolymer is usually used in an amount of 10 ⁴ to 10 ⁵ poise (380
° C) and its melting point is 302-310 ° C.

Commercially available products of such a copolymer of tetrafluoroethylene and a fluorovinyl monomer include, for example, "Teflon PFA" (trade name) manufactured by Mitsui Dupont Fluorochemicals Co., Ltd. and "Neoflon PFA" manufactured by Daikin Industries, Ltd. (Product name) and the like.

In the present invention, the tetrafluoroethylene-olefin copolymer (b) is a copolymer of tetrafluoroethylene and an olefin such as ethylene, propylene, and butene-1. A typical example is ethylene-
And tetrafluoroethylene copolymer (ETFE). The ethylene - tetrafluoroethylene copolymer of the general formula: is represented by _{CF 2 -CF 2 r CH 2 -CH} 2 s.

The above ethylene-tetrafluoroethylene copolymer (ET
FE) usually has a melt viscosity of 10 ⁴ to 10 ⁵ poise (300 to 330 ° C.), and its melting point is 260 ° C.

Commercial products of the ethylene-tetrafluoroethylene copolymer include, for example, "Neflon BTFE EP520" (trade name) manufactured by Daikin Industries, Ltd.

In the present invention, (b) polyvinylidene fluoride (PV
DF) is a polymer obtained by polymerizing vinylidene fluoride (CH ₂ = CF ₂ ), and is represented by the general formula: CH ₂ —CF _{2 t} .

Polyvinylidene fluoride having the above molecular structure usually has a melt viscosity of 2 × 10 ³ to 2 × 10 ⁶ (210 to 270 ° C.) and a melting point of 160 to 180 ° C. As such polyvinylidene fluoride, various grades such as those for injection molding and extrusion molding are manufactured, but are not particularly limited in the present invention.

Examples of commercially available polyvinylidene fluoride include “KF Polymer” (trade name) manufactured by Kureha Chemical Industry Co., Ltd. and “Neoflon PVDF” (trade name) manufactured by Daikin Industries, Ltd.

The vinylidene fluoride copolymer is a copolymer containing vinylidene fluoride and perfluoromonomers such as ethylene tetrafluoride and propylene hexafluoride as main monomers. The copolymer is not limited to a block or random copolymer, but may be a graft copolymer, and can be produced by irradiation or with a peroxide catalyst.

The polyarylene sulfide resin (c) used in the present invention has a repeating unit represented by the general formula: Ar-S (where Ar is an aromatic residue and S is sulfur). Here, as the aromatic residue (-Ar-) in the above general formula, for example, (Where X is fluorine, chlorine, bromine and CH ₃ , and m is a positive integer of 1 to 4).

As a representative of the above-mentioned polyarylene sulfide resins, a general formula: The polyphenylene sulfide resin (PPS) represented by these is mentioned. Further, a resin obtained by copolymerizing the above-mentioned polyphenylene sulfide resin with about 10 mol% or less of another monomer can also be used. The resin is not cross-linked between chain molecules, but may be partially cross-linked by a method such as heat treatment.

Such a polyphenylene sulfide resin is 30
The melt viscosity at 0 ° C is 20 to 30,000 poise, preferably 100 to 15,000 poise. Its melting point is usually 28
0-290 ° C.

As such a polyphenylene sulfide resin, various grades such as those for injection molding and extrusion molding are manufactured, but are not particularly limited in the present invention.

Commercially available polyphenylene sulfide resins include, for example, "Topren PPS" (trade name) manufactured by Topren Co., Ltd., "ASAHI PPS" (trade name) manufactured by Asahi Glass Co., Ltd., and "Shin-Etsu PPS" manufactured by Shin-Etsu Chemical Co., Ltd. (Trade name) and "Sastile" (trade name) manufactured by Hodogaya Chemical Co., Ltd.

The mixing ratio of the above components (a), (b) and (c) is as follows: component (a) / component (b) is 5/95 to 70 by volume ratio.
/ 30, preferably 15/85 to 50/50. (A) Component /
If the component (b) is less than 5/95, the effect of the component (a) is insufficient, while if it exceeds 70/30, the component (a) tends to aggregate alone in the polyarylene sulfide resin. In addition, a composition having good compatibility between the polyarylene sulfide resin and the fluororesin cannot be obtained.

The compounding ratio of (c) the polyarylene sulfide resin is 5/95 to 30/70, preferably 15/85 to 30/70, by the volume ratio of ((a) component + (b) component) / (c) component. It is. When the volume ratio is less than 5/95, the components (a) and (b) tend to agglomerate when kneaded with the component (c), and are not stably and uniformly dispersed in the component (c). On the other hand, if it exceeds 30/70, the effects of improving the heat resistance, chemical resistance, low frictional properties, abrasion resistance and the like due to the fluorine-containing resin are insufficient.

In the present invention, the mixing ratios of the various components are shown by volume ratio, but the volume ratio is obtained by dividing the weight of each component by its density.

In addition to the above components, the composition of the present invention may optionally contain silicone oil, molybdenum disulfide, a release agent, a lubricant, a heat stabilizer, a foaming agent, an inorganic filler, and the like.

Next, a method for producing the polyarylene sulfide resin composition of the present invention will be described.

In the present invention, first, the component (a) and the component (b) are kneaded (first kneading step). The first kneading step is (a)
The reaction is performed at a temperature equal to or higher than the melting point of the component and the component (b) and lower than the thermal decomposition starting temperature. Specifically, 310 to 340 ° C. is preferable, and especially 32
0-340 ° C is preferred. The time required for kneading is different depending on the mixing ratio of the resin and the kneading device to be used, for example, when using a Weissenberg extruder, preferably 1 to 30 minutes,
Particularly, 5 to 15 minutes are preferable.

Next, the kneaded product thus obtained is kneaded with the polyarylene sulfide resin composition and various additives to be added as necessary (second kneading step). The second kneading step is performed at a temperature lower than the melting point of the component (a) and higher than the melting points of the components (b) and (c). Specifically, when a polyphenylene sulfide resin is used as the polyarylene sulfide resin, the temperature is preferably 280 to 300 ° C, and particularly preferably 285 to 290 ° C. When the Weissenberg extruder is used, the time required for kneading is preferably 1 to 30 minutes, particularly preferably 5 to 15 minutes.

The method of the first and second kneading is not particularly limited, but the component (a) has a high viscosity even in a molten state at the time of the first melt kneading, and therefore, for example, a Weisenberg extruder or a screw. It is preferable to use a mold extruder or the like. Prior to the melt-kneading, it is preferable that the various components are previously mixed in the form of powder or pellets in the same manner as in the case of mixing a normal thermoplastic resin.

FIG. 1 shows a schematic diagram of the polyarylene sulfide resin composition of the present invention thus obtained. In FIG. 1, component (a) 2 is dispersed in a matrix 1 of a polyarylene sulfide resin in a state of being contained by component (b). The component (a) need not be entirely covered by the component (b) (4 'in the figure), and may be partially exposed (4 in the figure). Reference numeral 3 denotes particles of the component (b) alone.

The particle diameter of the component (a) included in the component (b) is usually 5 to 50 μm, preferably 5 to 15 μm. The particle size of the component (b) alone is usually less than 5 μm.

In FIG. 1, numbers are given only to particles whose characteristics are remarkable.

(Operation)

Since the polyarylene sulfide resin composition obtained by the production method of the present invention contains the component (b) as a compatibilizer for the components (a) and (c), the component (a) is (c) The polyarylene sulfide resin having a good compatibility, dark brown or black brown, which is uniformly dispersed in the component matrix and has an appearance characteristic of a polyarylene sulfide resin.

Observation of such a resin composition by an electron microscope reveals that a particulate matter (island structure) in which the fine particles of the component (a) are wrapped with the component (b) of the compatibilizer is (c) a polyarylene sulfide resin. It is uniformly dispersed in the phase (sea structure) of the composition.

The reason for obtaining such an effect is that, in the production method, the components (a) and (b) are first melt-kneaded,
After the component (a) is dispersed in the component (b), the kneaded product is further melt-kneaded with the component (c) at a predetermined temperature, so that the component (a) is included in the component (b). This is considered to be because the component (a) is favorably compatible with the component (c) via the component (b) which is present in the component (c) as it is and has an affinity for the component (c).

When a composition obtained by simultaneously kneading the components of the composition ratio of the present invention is observed, a white separated product is observed. When this white separated product was analyzed with a scanning X-ray microanalyzer, it was found to be a fluorine-based resin of the component (a) and the component (b). It is considered that this is because the component (a) is not compatible with the polyarylene sulfide resin, so that it is not possible to obtain a uniform composition by agglomeration.

Further, even in the case of having the first kneading step and the second kneading step as in the present invention, the temperature of the second kneading step is (a)
When the melting point is higher than the melting point of the component, a white isolate is also observed. This is because the temperature during the second kneading step is (a)
If the melting point of the component is higher than the melting point of the component, it becomes difficult to uniformly disperse the component (c) in the component (c) while maintaining the state in which the component (a) is bonded and dispersed in the component (b). It is considered that this is because the components are aggregated.

〔Example〕

 The present invention is described in more detail by the following examples.

In addition, the raw material resin used in each Example and Comparative Example is as follows.

(A) Component Polytetrafluoroethylene PTFE: [Rublon L-5, manufactured by Daikin Industries, Ltd., melting point: 327 ° C] Tetrafluoroethylene-perfluoroalkylvinyl ether copolymer PFA: [Mitsui DuPont Fluorochemical Co., Ltd.] "Teflon
PFA340J, melting point 302-310 ° C] (b) Component ethylene-tetrafluoroethylene copolymer ETFE: “NEOFLON ETFE EP52 manufactured by Daikin Industries, Ltd.
0, melting point 260 ° C) polyvinylidene fluoride PVDF: [“solef # 1010” manufactured by Solvay of Belgium, melting point 17
7 ° C] (c) Component Polyphenylene sulfide resin PPS: [Toplen T-4 manufactured by Topren Co., Ltd., melting point 28
0 ° C.] Examples 1 to 7 and Comparative Examples 1 to 3 At the ratios shown in Table 1, the polytetrafluoroethylene or the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer of the component (a) and the component (b) were used. Ethylene-tetrafluoroethylene copolymer or polyvinylidene fluoride was fed to a Weissenberg extruder, and 70 rp
The mixture was melt-kneaded at m and pelletized.

Next, each of the obtained pellets and the polyphenylene sulfide resin as the component (c) were melt-kneaded at the ratios shown in Table 1, and then supplied to a Weissenberg extruder, and the rotation speed was adjusted.
The mixture was melted and kneaded at 70 rpm to obtain pellets of the polyphenylene sulfide resin composition.

The pellets of the polyphenylene sulfide resin composition thus obtained were pressed and observed as a 70 mmφ × 0.3 mm disk. In addition, a sample of the polyphenylene sulfide resin composition obtained by a freeze rupture method was observed with a scanning electron microscope. Based on the above observation results, compatibility was evaluated according to the following criteria.

：: A brown or black-brown uniform appearance, and the fluororesin island structure was uniformly dispersed even under microscopic observation.

Δ: A white linear substance of a fluororesin was slightly observed in appearance.

X: A white separated product of a fluororesin is observed in appearance.

 The results are shown in Table 1 together with the kneading temperature.

For comparison, the compositions (Comparative Examples 1 and 2) in which the mixing ratio of the component (a), the component (b) and the component (c) were out of the range of the present invention, and the components were mixed in one step. The composition (Comparative Example 3) was pelletized in the same manner, and the compatibility was similarly evaluated. The results are shown in Table 1.

As is clear from Table 1, the polyarylene sulfide resin composition obtained by the production method of the present invention has a brown or black brown uniform appearance, and a fluorine-based resin,
It is well compatible with the polyphenylene sulfide resin composition.

On the other hand, in the compositions of Comparative Examples 1 to 3, white linear substances or white separated substances were observed in the appearance.

〔The invention's effect〕

As described in detail above, the polyarylene sulfide resin composition obtained by the production method of the present invention comprises (a) polytetrafluoroethylene and / or a copolymer containing tetrafluoroethylene and a fluorovinyl monomer, b) one or more selected from tetrafluoroethylene-olefin copolymer, polyvinylidene fluoride, and vinylidene fluoride copolymer, and (a) and (b)
After melt-kneading at a temperature not lower than the melting point of (a), the obtained kneaded product and (c) a polyarylene sulfide resin are melt-kneaded at a temperature not lower than the melting point of (c) and lower than the melting point of (a). Therefore, the compatibility between the component (a) and the component (c) is good.

The polyarylene sulfide resin composition obtained by such a production method of the present invention has heat resistance, chemical resistance,
It has excellent low friction and wear resistance, and is suitable for sliding members such as gears, bearings, and sealing materials.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a compatibilized state of the polyarylene sulfide resin composition obtained by the production method of the present invention. 1... Polyarylene sulfide resin matrix 2... (A) component 3... (B) component 4, 4 ′... (B) component (a) component

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 81/00-81/02 C08L 27/12-27/20

Claims (2)

(57) [Claims] (1) 5 to 30 parts by volume of a copolymer containing polytetrafluoroethylene and / or tetrafluoroethylene and a fluorovinyl monomer, (b) a tetrafluoroethylene-olefin copolymer, polyvinylidene fluoride , One or more selected from vinylidene fluoride copolymers in an amount of 95 to 70 parts by volume as described in (a) and (b) above.
Is melt-kneaded at a temperature equal to or higher than the melting point, and then 5 to 30 parts by volume of the obtained kneaded material and (c) 95 to 70 parts by volume of the polyarylene sulfide resin are mixed with the melting points of (b) and (c) or higher. A method for producing a polyarylene sulfide resin composition, wherein the composition is melt-kneaded at a temperature lower than the melting point of (a). 2. The method for producing a polyarylene sulfide resin composition according to claim 1, wherein said tetrafluoroethylene-olefin copolymer is an ethylene-tetrafluoroethylene copolymer.