JPH10182968A - Polyarylene sulfide resin composition and sliding member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyarylene sulfide resin composition good in melt flowability on melt-molding treatment, excellent in mechanical strengths, having extremely high dimensional accuracy, excellent in slidability on magnetic tapes, and suitable for contact members with magnetic tapes, such as VTR cylinders (magnetic drums), and to produce a sliding member. SOLUTION: This resin composition comprises (A) 20-40wt.% of a resin component comprising 40-90wt.% of a polyarylene sulfide resin and 60-10wt.% of a thermoplastic resin except the polyarylene sulfide resin, (B) 60-80wt.% of metasilicate whiskers having an average fiber diameter of <=5μm and an average aspect ratio of >=5, and further (C) an inorganic filler so that [(B)+(C)] is 60-80wt.% and (B) is >=15wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyarylene sulfide (hereinafter sometimes referred to as PAS) resin composition. More specifically, the present invention relates to a PAS composition having high dimensional accuracy and slidability suitably used for precision equipment and electronic parts, and a sliding member using the composition.

[0002]

2. Description of the Related Art Polyarylene sulfide resin is an engineering plastic having excellent mechanical properties such as heat resistance, flame retardancy, rigidity and dimensional accuracy, and is therefore used for electronic parts, electric parts and the like. . However, in providing these uses, depending on the purpose of use,
For example, as in the case of a magnetic drum in a video tape recorder (VTR), specific performance such as higher dimensional accuracy and slidability with a tape may be required.

Conventionally, in order to obtain high dimensional accuracy in polyarylene sulfide resin, potassium titanate whiskers, zinc oxide whiskers, aluminum borate whiskers,
It has been widely used to add potassium carbonate whiskers and the like. However, when these whiskers are blended with the polyarylene sulfide resin, although the dimensional accuracy is improved, the specific thixotropy seen when the whiskers are added is developed, and therefore, a composition with a high filling amount is kneaded. However, when a molded article is obtained by injection molding, defects such as short shots are caused. Therefore, the amount added has to be limited, and there is a limit in improving the dimensional accuracy. There is also a problem that the dimensional change rate cannot be sufficiently reduced due to the hygroscopicity of the material.

When these whiskers are added,
Further, the required properties, that is, the slidability with respect to a magnetic tape, became inferior and could not function sufficiently as a VTR cylinder (magnetic drum). on the other hand,
As a method of improving the slidability with respect to a magnetic tape, for example, a method of adding carbon fibers or carbon beads has been proposed. However, when carbon fibers, especially chopped carbon fibers, are added, anisotropy is generated, and there is a disadvantage that the roundness, flatness, and dimensional accuracy are poor.

[0005] For this reason, in the present situation, a satisfactory resin has not been obtained in the past when resinized magnetic drums using aluminum cut products have been used. Incidentally, the present inventors have previously described a polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a calcium metasilicate whisker having a specific property, and a polyarylene sulfide resin and a calcium metasilicate whisker having a specific property and an inorganic filler. A polyarylene sulfide resin composition made of a material has been proposed (Japanese Patent Application No. 8-2877).
No. 87). When a VTR cylinder was molded, the slidability was satisfactory there, but there was also a demand for a molded product with higher dimensional accuracy that further satisfies the warpage of the lead portion for leading the magnetic tape.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has good fluidity during molding.
Excellent mechanical strength and extremely high dimensional accuracy, and excellent slidability against magnetic tape. Used for electrical and electronic parts, especially for contact parts with magnetic tape such as VTR cylinders (magnetic drums). It is an object of the present invention to provide a polyarylene sulfide resin composition suitable for a sliding member to be obtained, and a sliding member comprising the resin composition.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object can be achieved by a polyarylene sulfide resin composition having a specific composition. The present invention has been made based on such findings. That is, the present invention relates to a resin component (A) composed of a polyarylene sulfide resin (A-1) and a thermoplastic resin (A-2) other than the polyarylene sulfide resin.
A polyarylene sulfide resin composition (1) comprising 40 to 80% by weight of calcium metasilicate whisker (B) having 40% by weight, an average fiber diameter of 5 μm or less, and an average aspect ratio of 5 or more. Yes, and
Resin component (A) composed of polyarylene sulfide resin (A-1) and thermoplastic resin (A-2) other than polyarylene sulfide resin, 20 to 40% by weight, average fiber diameter of 5 μm or less, and average aspect ratio Is composed of calcium metasilicate whiskers (B) having an amount of 5 or more and an inorganic filler (C), wherein (B) + (C) is 60 to 80% by weight and (B) is 15% by weight or more. It is intended to provide an arylene sulfide resin composition (2).
Further, the resin component (A) of the above (1) or (2) contains 40 to 90% by weight of the polyarylene sulfide resin (A-1) and 60% of the thermoplastic resin (A-2) other than the polyarylene sulfide resin. The present invention provides a polyarylene sulfide resin composition comprising from 10 to 10% by weight. The present invention also provides a molded product obtained by molding the polyarylene sulfide resin composition, and provides a sliding member used for a contact portion with a magnetic tape.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the polyarylene sulfide resin composition of the present invention will be specifically described for each component. 1. Polyarylene sulfide resin (A-1) Polyarylene sulfide (PA) used in the present invention
S) (A-1) is a polymer containing at least 70 mol% of a repeating unit represented by the structural formula -Ar-S- (where Ar is an arylene group). )

[0009]

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(Wherein R ¹ is an alkyl group having 6 or less carbon atoms, an alkoxy group, a phenyl group, a carboxylic acid / metal salt,
A substituent selected from an amino group, a nitro group, a halogen atom such as fluorine, chlorine, and bromine, and m is an integer of 0 to 4. N is an average degree of polymerization and is in the range of 1.3 to 30), and is a polyphenylene sulfide having a repeating unit represented by at least 70 mol%. Among them, α-chloronaphthalene solution (concentration 0.4 g / dl), logarithmic viscosity at 206 ° C. is 0.1 to 0.5 (dl / g), preferably 0.13 to 0.4 (dl / g), Preferably 0.
Those in the range of 15 to 0.35 (dl / g) are suitable. In general, PAS is known to have a substantially linear, molecular structure having no branched or cross-linked structure, and a structure having a branched or cross-linked structure, according to the present invention. Is also effective. Preferred PASs for use in the present invention are homopolymers or copolymers containing at least 70 mol%, more preferably at least 80 mol%, of paraphenylene sulfide units as repeating units (hereinafter abbreviated as PPS). If this repeating unit is less than 70 mol%, the original crystallinity, which is a characteristic of a crystalline polymer, tends to be low, and sufficient mechanical properties tend not to be obtained, which is not preferable. Examples of the copolymerizable structural unit include a metaphenylene sulfide unit, an orthophenylene sulfide unit, a p, p′-diphenylene ketone sulfide unit, a p, p′-diphenylene sulfone sulfide unit, a p, p′-biphenylene sulfide unit, and p , P'-diphenylene ether sulfide unit, p, p'-diphenylene methylene sulfide unit,
p, p'-Diphenylene cumenyl sulfide unit, naphthyl sulfide unit and the like. Further, as the polyarylene sulfide of the present invention, in addition to the above-mentioned substantially linear polymer, a branched or cross-linked polyarylene sulfide polymerized by using a small amount of a monomer having three or more functional groups as a part of the monomer is also used. Further, a blended polymer obtained by blending the above-mentioned linear polymer with the above-mentioned linear polymer can also be used. Furthermore, as the PAS used as the component (A-1) used in the present invention, a polymer obtained by increasing the melt viscosity of a linear polymer having a relatively low molecular weight by oxidative crosslinking or thermal crosslinking and improving moldability can be used. . The PAS resin can be obtained, for example, by subjecting a dihaloaromatic compound and a sulfur source to a polycondensation reaction in an organic polar solvent by a method known per se.
Preferable examples of the PAS resin include, for example, polyphenylene sulfide represented by the following structural formula (II) (hereinafter referred to as P
It may be called PS. ) Resins.

[0011]

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In the composition of the present invention, regarding the molecular weight,
Within the range of the logarithmic viscosity, preferably, the melt viscosity is 50 ≦
Within the range of η _app ≤ 2,000 (poise), a material having a low molecular weight which does not adversely affect the mechanical degree is used.
Here, η _app is a resin temperature 3 measured by a capillary viscometer.
It refers to the apparent viscosity at 00 ° C. and a shear rate of 20 sec ⁻¹ . 2. Thermoplastic Resin (A-2) The thermoplastic resin used here is not particularly limited, and any thermoplastic resin having an effect of reducing warpage by being used as one component of the composition of the present invention may be used. Specifically, polycarbonate resin, polyetherimide resin, polyaromatic ether or thioether resin, polyaromatic ester resin, polysulfone resin, polyolefin resin, polystyrene resin, polyvinyl chloride resin, polyamide resin Resins, polyester resins, polyacetal resins, acrylate resins and the like can be mentioned. Above all, the lower the crystallinity of the resin, the smaller the volume shrinkage at Tmc (abbreviation of Melt Crystallization Temperature, which is the temperature at which it crystallizes from a molten state). . Specifically, so-called amorphous resins such as polycarbonate resins, polyetherimide resins, polyaromatic ether or thioether resins, polyaromatic ester resins, and polysulfone resins are preferably used, and crystalline resins are preferably used. When is used, those having a low crystallinity are preferably used.

As the polycarbonate resin, 4,
4'-dihydroxydiarylalkane-based polycarbonate, particularly bisphenol A-based polycarbonate, is preferably used. Further, modified bisphenol A-based polycarbonate and flame-retarded bisphenol A-based polycarbonate can also be used. Examples of the polyaromatic ether or thioether-based resin include polyphenylene ether, polyphenylene ether grafted with styrene, polyether ether ketone, polyphenylene sulfide, and the like.

Examples of the polyaromatic ester resin include polyarylate. Examples of the polysulfone-based resin include polysulfone, polyether sulfone, and polyaryl sulfone.
Examples of the polyolefin resin include, for example, α-olefin homopolymers such as ethylene, propylene, butene-1, 4-methylpentene-1 and the like, copolymers thereof, and other copolymerizable unsaturated monomers. And a copolymer with a monomer.

As the styrene resin, for example,
Homopolymers such as styrene and α-methylstyrene, copolymers thereof, and copolymers with unsaturated monomers copolymerizable therewith are exemplified. Representative examples include polystyrene, syndiotactic polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS),
Acrylonitrile-styrene copolymer (AS) and the like can be mentioned.

As the polyvinyl chloride resin, for example,
Examples thereof include a vinyl chloride homopolymer and a copolymer of vinyl chloride with an unsaturated monomer copolymerizable with vinyl chloride. As the polyamide resin, for example, 6-nylon, 12-nylon, 6,6-nylon, 6,10-nylon, 6,12
-Nylon, 11-nylon and the like.

Examples of the polyester resin include polyethylene terephthalate and polybutylene terephthalate. Examples of the polyacetal-based resin include a polyoxymethylene homopolymer and a formaldehyde-ethylene oxide copolymer obtained from trioxane and ethylene oxide.

Examples of the acrylate resin include a methacrylate polymer and an acrylate polymer. In the present invention, the above-mentioned thermoplastic resins may be used alone or in combination of two or more. 3. Calcium metasilicate whisker (B) Examples of the calcium metasilicate whisker (B) in the present invention include wollastonite and the like, that is, white acicular minerals represented by CaSiO ₃ and the like. The calcium metasilicate whisker (B) may be subjected to a surface treatment with a coupling agent, preferably aminosilane, vinylsilane, phenylsilane, epoxysilane, other silane coupling agent, or the like. In the case of using a material that has not been subjected to a surface treatment, the mechanical strength of the molded product is reduced and moisture absorption is increased, and the dimensional stability against moisture is deteriorated.

Further, calcium metasilicate whisker (B)
The average fiber diameter is 5 μm or less, preferably 3 μm
It must be: If the average fiber diameter exceeds 5 μm, the rigidity of the molded product, particularly the rigidity near the surface, becomes insufficient, and as a result, the sliding property with the tape becomes poor. The average aspect ratio needs to be 5 or more, preferably 10 or more. When the average aspect ratio is smaller than 5, the slidability with the tape also becomes poor. 4. Inorganic Filler (C) The inorganic filler is not particularly limited, but a granular filler, a plate-like filler or milled fiber is preferably used.

The particulate filler is irregular or spherical in shape and has an average aspect ratio of about 2 or less. Specific examples include calcium carbonate, silica, glass beads, calcined carbon, alumina, aluminum borate, and carbon black. The plate-like filler is a plate-like filler having a small thickness with respect to the length in the vertical and horizontal directions. Specific examples include mica, graphite, kaolin, talc, glass flake, and the like.

The term "milled fiber" refers to a fibrous material obtained by pulverizing a so-called fibrous material with a mill or the like, or a fibrous material obtained by pulverizing and classifying a lump of minerals. B), except for those listed as components), milled carbon fibers, milled glass fibers, and the like. 5. Mixing ratio of each component (1) Resin component (A) comprising PAS resin (A-1) and thermoplastic resin (A-2) other than PAS resin PAS resin (A-1) is 40 to 90% by weight, PAS It is preferable that the thermoplastic resin (A-2) other than the resin be 60 to 10% by weight. When the amount of the PAS resin (A-1) is less than 40% by weight, the surface of the molded article becomes substantially a resin other than the PAS resin, and the various performances of the present invention may not be exhibited such as an increase in the coefficient of friction. When the thermoplastic resin (A-2) other than the PAS resin is less than 10% by weight,
When a VTR cylinder or the like is formed, there is a possibility that the warp of a lead portion for leading a magnetic tape becomes large. (2) When the inorganic filler (C) is not blended: 20 to 40% by weight, preferably 25% by weight of the resin component (A).
60 to 80% by weight, preferably 65 to 75% by weight of calcium metasilicate whisker (B),
It is. If the amount of the resin component (A) is less than 20% by weight, kneading of the composition becomes difficult, and even if it is obtained, the composition becomes brittle. If it exceeds 40% by weight, both dimensional accuracy and slidability will be poor. (3) In the case of blending the inorganic filler (C) The blending ratio of the resin component (A) is the same as described above. Therefore, the total of the calcium metasilicate whisker (B) and the inorganic filler (C) is 60 to 80% by weight, preferably 65 to 7%.
That is, 5% by weight. In this case, the amount of the calcium metasilicate whisker (B) needs to be 30% by weight or more, preferably 40% by weight or more. If the amount is less than 30% by weight, the slidability becomes poor. 5. Other Components In addition to the above components, other components may be added to the polyarylene sulfide resin composition of the present invention, if necessary, as long as the object of the present invention is not impaired. Other components include, for example, antioxidants, heat stabilizers,
Various additives such as lubricants, coloring agents, plasticizers, conductivity-imparting agents, polyamides, epoxy resins, silicone resins, silicone oils, silicone oils having various functional groups introduced, thermosetting resins, hydrogenated SBS, hydrogen Added NBR,
Rubbers such as silicone rubber and fluorine rubber, pigments and the like can be mentioned. The content of other components can be appropriately selected within a range that does not impair the purpose of the present invention. 6. Preparation of PAS Resin Composition The PAS resin composition of the present invention comprises the resin component (A), the calcium metasilicate whisker (B), and the inorganic filler (C), and other components selected as necessary. It can be prepared by blending the ingredients with each other and then melt-kneading the ingredients.

The above-mentioned melt-kneading can be carried out by an ordinary known method. In any case, the above-mentioned components are uniformly mixed and dispersed in a resin to obtain a predetermined resin composition. I do. For the melt-kneading, a twin-screw extruder, a single-screw extruder or the like can usually be suitably used.

The conditions for the melt-kneading are not particularly limited. However, in order to limit decomposition or foaming of other components added as necessary, avoid extremely high temperatures or extremely long residence times. Is preferred. The specific temperature is usually 280 to 350 ° C, preferably 285 to 330 ° C. The PAS resin composition thus prepared is usually granulated or cut into a shape and size suitable as a material for secondary processing such as pellets, particularly as a material for injection molding, and is provided to each application as appropriate. . 7. A sliding member, which is a molded product obtained by molding the PAS resin composition and is used for a contact portion with a magnetic tape.

The molded product obtained by molding the PAS resin composition according to the present invention has excellent mechanical strength, extremely high dimensional accuracy, and excellent slidability on a magnetic tape. Therefore, it is suitably used as a sliding member for electric / electronic parts, especially a VTR cylinder (magnetic drum), a tape, particularly a tape guide for an audio tape recorder, a guide for the tape, and a contact portion with a magnetic tape.

[0025]

EXAMPLES Hereinafter, the polyarylene sulfide resin composition of the present invention will be described more specifically with reference to examples. [Examples 1 to 8, Comparative Examples 1 to 4] <Preparation of Sample> Twin screw extruder (TEM3 manufactured by Toshiba Machine Co., Ltd.)
5) Using a Henschel mixer to uniformly mix the following polyphenylene sulfide resin (PPS resin) and other components at the compounding ratios shown in Table 1 and setting the cylinder temperature to 300 to 320 ° C. The mixture was melt-kneaded to produce pellets. <Preparation of Component (A-1) (PPS)> In a polymerization tank equipped with a stirrer, 833 mol of hydrous sodium sulfide (Na ₂ S ₅ H ₂ O) 830 mol of lithium chloride (LiCl) and NMP 500
One liter was added, and dehydration treatment was performed for 1 hour while maintaining the temperature at 145 ° C. under reduced pressure. Then, the reaction system was cooled to 45 ° C., and 905 mol of dichlorobenzene (DCB) was added.
Polymerized for hours. The contents were washed 5 times with hot water, once with 170 ° C. N-methyl-2-pyrrolidone (NMP) and 3 times with water, and dried at 185 ° C. to obtain PPS. <Other components blended in PPS resin> (A-2) component ・ Polycarbonate Polycarbonate manufactured by Idemitsu Petrochemical Co., Ltd. (trade name: Idemitsu Toughlon) ・ Polyetherimide Polyetherimide manufactured by Nippon GE Plastics (trade name: Ultem 1000) Polyether sulfone Polyether sulfone manufactured by Teijin Amoco Engineering Plastics Co., Ltd. (trade name: Udel 1000) Modified polyphenylene ether Noryl (B) component manufactured by GE Plastics Co., Ltd. Calcium whisker (product grade NYGLOS) (average fiber diameter 5 μm or less, average aspect ratio 10 or more) (C) component ・ Wollastonite whisker 2 Calcium metasilicate whisker (product grade NYAD G) manufactured by NYCO, USA Average fiber diameter 5μm or more, average aspect ratio 12) ・ Milled carbon fiber: Kureha Chemical Co., trade name MT
101 ・ Mica: Kuraray, trade name 200D ・ Silica: Nitto Denko Corporation, trade name FB-74 ・ Alumina: Showa Denko Corporation, trade name AS40 ・ Calcium carbonate: Shiraishi Industry Co., trade name Whiteton P30 ・Ketjen Black: Lion-made, trade name EC-600
JD <Evaluation of physical properties>-Roundness: A magnetic drum (VTR lower cylinder) having a diameter of 60 mm and a height of 15 mm was molded by an injection molding machine (J50E-P manufactured by Nippon Steel Works, Ltd.) and left at room temperature for 24 hours. The roundness was measured with a roundness measuring machine (RA-2 manufactured by Mitoyo Seisakusho). The molding conditions of the molded product were as follows: resin temperature 340 ° C,
The mold temperature was set to 135 ° C. Amount of warpage: In the lower cylinder test piece as shown in FIG. 2, when the outer side is parallel to the center axis, the amount of warpage is set to 0, and as shown in FIG. Is displaced without being parallel to the central axis, the amount of displacement is defined as warpage = x. -Sliding property with magnetic tape: The friction coefficient with the magnetic tape was measured with a shuttle type sliding tester shown in Fig. 4 using a magnetic drum molded for measuring the roundness. The measurement conditions were as follows: video tape Hi8 ME120 manufactured by Sony Corporation as the tape.
Was used.

The measurement was performed as follows. About 60c
m, a load of 20 g is applied to one end of the tape, and the other end is connected to a tensiometer.
The tape was slid on the surface of the molded product by reciprocating 100 times at a speed of 30 seconds over a distance of 30 mm. Thereafter, when the tension of the T ₁ at one end, to measure the tension T ₂ of the time of pulling the tape was determined μ friction coefficient by the following equation.

Μ = (2 / π) · ln (T ₂ / T ₁ ) <Evaluation Results> The evaluation results are shown in Table 1.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As described above, the fluidity at the time of molding is excellent, the mechanical strength is excellent, the dimensional accuracy is extremely high, and the slidability against the magnetic tape and the warpage are remarkably excellent. For electrical and electronic components, especially VT
It is possible to provide a polyarylene sulfide resin composition suitable for a sliding member used in a contact portion with a magnetic tape such as an R cylinder (magnetic drum) and a sliding member made of the resin composition.

[Brief description of the drawings]

FIG. 1 is a schematic top view of a test piece for a warpage amount test.

FIG. 2 is a schematic cross-sectional view of a test piece for a warpage amount test, taken along the line A-A ′.

FIG. 3 is a schematic cross-sectional view taken along the line AA ′ when the amount of warpage is x in the test piece for warpage amount test.

FIG. 4 is a schematic sectional view of a shuttle type sliding test machine.

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Claims (6)

[Claims] 1. A polyarylene sulfide resin (A-
Metasilicic acid having a resin component (A) composed of a thermoplastic resin (A-2) other than 1) and a polyarylene sulfide resin in an amount of 20 to 40% by weight, an average fiber diameter of 5 μm or less, and an average aspect ratio of 5 or more. Calcium whisker (B)
A polyarylene sulfide resin composition comprising 60 to 80% by weight. 2. A polyarylene sulfide resin (A-
Metasilicic acid having a resin component (A) composed of a thermoplastic resin (A-2) other than 1) and a polyarylene sulfide resin in an amount of 20 to 40% by weight, an average fiber diameter of 5 μm or less, and an average aspect ratio of 5 or more. Calcium whisker (B)
And (B) + (C) are 60
A polyarylene sulfide resin composition in which the content of (B) is 15% by weight or more. 3. The resin component (A) according to claim 1 or 2,
Has a polyarylene sulfide resin (A-1) of 40 to
3. The polyarylene sulfide resin composition according to claim 1, wherein the thermoplastic resin (A-2) other than the polyarylene sulfide resin is 90% by weight and 60 to 10% by weight. 4. 4. The thermoplastic resin (A-2) according to claim 1, wherein the thermoplastic resin (A-2) is a polycarbonate resin, a polyetherimide resin, a polyaromatic ether or thioether resin, or a polyaromatic ester resin. The polyarylene sulfide resin composition according to any one of claims 1 to 3, which is at least one member selected from the group consisting of a polysulfone resin and a polysulfone resin. 5. The inorganic filler (C) according to claim 2,
The polyarylene sulfide resin composition according to claim 2, wherein is a granular filler, a plate-like filler, or a milled fiber. 6. A sliding member which is a molded article made of the polyarylene sulfide resin composition according to any one of claims 1 to 5, and is used for a contact portion with a magnetic tape.