WO2018096908A1

WO2018096908A1 - Resin composition

Info

Publication number: WO2018096908A1
Application number: PCT/JP2017/039768
Authority: WO
Inventors: 吉田　健; 圭祐羽儀; 宏和湯川
Original assignee: ダイキン工業株式会社
Priority date: 2016-11-28
Filing date: 2017-11-02
Publication date: 2018-05-31
Also published as: JP2018087271A; JP6520899B2

Abstract

Provided is a resin composition which has a small coefficient of friction and which does not tend to damage the surface of an aluminum article when coming into contact with the aluminum article. The resin composition is characterized by comprising: a heat resistant resin; a graphite yarn (A) having a crystallite size in the c axis direction of 100 Å or less; and a graphite yarn (B) having a crystallite size in the c axis direction of greater than 100 Å.

Description

Resin composition

The present invention relates to a resin composition.

In recent years, as materials used for sliding parts of automobiles and industrial equipment, there is an increasing need for functional enhancement such as weight reduction, downsizing, improved wear resistance due to fuel efficiency reduction, friction reduction, and low friction. .
As materials used for the sliding parts as described above, resin materials containing fillers have been used for the purpose of improving dimensional stability, creep resistance, wear resistance, and the like.

For example, Patent Document 1 discloses a pressure-resistant slidability formed by blending carbon fiber and a granular inorganic compound with a modified tetrafluoroethylene resin composed of a copolymer of tetrafluoroethylene and partially modified tetrafluoroethylene. A fluorinated ethylene resin composition is described.

Patent Document 2 describes a resin composition for sliding parts comprising a specific proportion of (a) carbon fiber, (b) metal powder, and (c) a melt-processable fluorine-containing resin.

In Patent Document 3, modified polytetrafluoroethylene is 60 to 90% by weight, the average fiber diameter is 5 to 30 μm, the first carbon fiber having an average fiber length of 20 to 60 μm is 10 to 30% by weight, and the average fiber diameter is 1 to 10% by weight of second carbon fibers having an average fiber length of 90 to 200 μm, and the first carbon fibers and the second carbon fibers are pitch-based carbon fibers having a random structure A shaft seal material for a car air conditioner using a tetrafluoroethylene composition is described.

Patent Document 4 describes a resin molding material containing a resin, a carbon substance, and an inorganic substance, and containing an adhesive carbon substance as the carbon substance.

Patent Document 5 is a composite of a specific thermoplastic resin and a carbon fiber having a specific aspect ratio, satisfies the following requirements (A) to (E), and has a thermal conductivity of 0.7 W / m. A heat-resistant heat conducting composite material characterized by being K or higher is described.
(A) At least 50% by weight or more of the thermoplastic resin is made of a fluororesin,
(B) The carbon fiber is a graphitized carbon fiber using mesophase pitch as a starting material,
(C) the true density of the carbon fiber is 1.7 to 2.5 g / cc,
(D) The crystallite size in the c-axis direction and ab-axis direction of the graphite crystal contained in the carbon fiber is both 20 nm or more,
(E) Carbon fiber is mixed in the composite material at a ratio of 5 to 50% by weight.

JP 2002-128981 A JP-A-5-320455 JP 2010-216612 A International Publication No. 2007/055338 JP 2008-208159 A

However, in the prior art, if the wear coefficient of the sealing material or the like is reduced, there is room for improvement in that the surface is easily damaged when it comes into contact with an aluminum article that is a soft metal.
The present invention has been made in view of the above-described present situation, and an object thereof is to provide a resin composition having a small wear coefficient and hardly damaging the surface of the aluminum article when contacted with the aluminum article.

As a result of earnestly examining the means for solving the above problems, the present inventors pay attention to the filler to be blended in the resin composition, and by using two specific types of graphite yarn as the filler, the wear coefficient is reduced. The inventors have found that a composition that is small and hardly scratches the surface even when it comes into contact with an aluminum article can be obtained, and the present invention has been completed.
The present invention includes a heat-resistant resin, a graphite yarn (A) having a crystallite size in the c-axis direction of 100 Å or less, and a graphite yarn (B) having a crystallite size in the c-axis direction of more than 100 Å. It is a resin composition.

In the resin composition of the present invention, the total content of the graphite yarn (A) and the graphite yarn (B) is preferably 3 to 40% by mass with respect to the resin composition.

In the resin composition of the present invention, the mass ratio (A / B) of the content of the graphite yarn (A) and the graphite yarn (B) is 1.0 / 9.0 to 9.9 / 0.1. Is preferred.

The graphite yarn (A) is preferably other than pitch-based anisotropic graphite yarn.

The graphite yarn (B) is preferably a pitch-based anisotropic graphite yarn.

The heat resistant resin is preferably at least one selected from the group consisting of a fluororesin, a polyether ketone resin, a polyarylene sulfide resin, and a phenol resin.

The resin composition of the present invention has a small wear coefficient and is less likely to damage the surface of the aluminum article when it comes into contact with the aluminum article.

Hereinafter, the present invention will be specifically described.

The resin composition of the present invention includes a heat-resistant resin, a graphite yarn (A) having a crystallite size in the c-axis direction of 100 Å or less, and a graphite yarn (B) having a crystallite size in the c-axis direction of more than 100 Å. Since the resin composition of the present invention has the above-described configuration, the wear coefficient is small, and when the resin composition comes into contact with the aluminum article, the surface of the aluminum article is hardly damaged. Moreover, since the said heat resistant resin is included, it can be used also at the temperature exceeding 150 degreeC.
It seemed difficult to provide a resin composition that is less likely to damage soft aluminum articles despite having a low wear coefficient. However, the reason why the resin composition of the present invention exhibits the above-described excellent effect is that the graphite yarn having a small crystallite size makes it difficult to wear the resin composition, and at the same time, the graphite yarn having a large crystallite size is the resin composition. This is considered to be because heat generated by friction with the aluminum article is released to the outside by improving the heat dissipation of the aluminum article, thereby reducing damage to the aluminum article.

The heat-resistant resin may be any resin that is generally recognized as having heat resistance, but preferably has a melting point of 150 ° C. or higher, for example. More preferably, it is 170 degreeC or more. The heat resistant resin is preferably at least one selected from the group consisting of a thermoplastic resin and a thermosetting resin, and the thermoplastic resin of the heat resistant resin includes a fluororesin, a polyamideimide resin, and a polyimide resin. Selected from the group consisting of: polyethersulfone resin, polyetherimide resin, polyetherketone resin, aromatic polyester resin, polyarylene sulfide resin, polyethernitrile resin, aromatic thermoplastic polyimide resin, and polyamide 4-6 resin At least one kind of resin is preferable, and a fluororesin is more preferable from the viewpoint of chemical stability and chemical resistance.
Examples of the polyether ketone resin include polyether ketone, polyether ether ketone, polyether ketone ketone, and polyether ether ketone ketone.
Moreover, a phenol resin etc. are mentioned as a thermosetting resin.
The heat resistant resin is preferably at least one selected from the group consisting of a fluororesin, a polyether ketone resin, a polyarylene sulfide resin, and a phenol resin.
The said melting | fusing point is the value calculated | required as temperature corresponding to the maximum value in the heat of fusion curve when it heats up at a speed | rate of 10 degree-C / min using a differential scanning calorimetry (DSC) apparatus.

Examples of the fluororesin include polytetrafluoroethylene [PTFE], tetrafluoroethylene [TFE] / perfluoro (alkyl vinyl ether) [PAVE] copolymer [PFA], and TFE / hexafluoropropylene [HFP] copolymer [FEP]. ], Ethylene [Et] / TFE copolymer [ETFE], Et / TFE / HFP copolymer, polychlorotrifluoroethylene [PCTFE], chlorotrifluoroethylene [CTFE] / TFE copolymer, Et / CTFE copolymer Examples thereof include a polymer, polyvinylidene fluoride [PVDF], and polyvinyl fluoride [PVF]. Among these, from the viewpoint of heat resistance, at least selected from the group consisting of PTFE, PFA, FEP, ETFE, Et / TFE / HFP copolymer, PCTFE, CTFE / TFE copolymer, Et / CTFE copolymer and PVDF. One type is preferred, at least one selected from the group consisting of PTFE, PFA, FEP and ETFE is more preferred, and PTFE is still more preferred from the viewpoint of sealing properties and sliding properties.

The PTFE may be homo-PTFE containing only TFE units or modified PTFE containing TFE units and modified monomer units based on a modified monomer copolymerizable with TFE.
The PTFE may be high molecular weight PTFE having non-melt processability and fibrillation property, or may be low molecular weight PTFE having melt processability and no fibrillation property. High molecular weight PTFE having melt processability and fibrillation properties is preferred.

The modifying monomer is not particularly limited as long as it can be copolymerized with TFE. For example, perfluoroolefin such as hexafluoropropylene [HFP]; chlorofluoroolefin such as chlorotrifluoroethylene [CTFE]; Examples thereof include hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perfluorovinyl ether; perfluoroalkylethylene; ethylene; fluorine-containing vinyl ether having a nitrile group. Moreover, the modified | denatured monomer to be used may be 1 type, and multiple types may be sufficient as it.

It does not specifically limit as said perfluoro vinyl ether, For example, following General formula (1)
CF ₂ = CF-ORf ¹ (1)
(Wherein, Rf ¹ represents a perfluoro organic group), and the like. In the present specification, the “perfluoro organic group” means an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoro organic group may have ether oxygen.

Examples of the perfluorovinyl ether include perfluoro (alkyl vinyl ether) [PAVE] in which Rf ¹ represents a perfluoroalkyl group having 1 to 10 carbon atoms in the general formula (1). The perfluoroalkyl group preferably has 1 to 5 carbon atoms.

Examples of the perfluoroalkyl group in the PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group. Purple propyl vinyl ether [PPVE] whose group is a perfluoropropyl group is preferred.
As the perfluorovinyl ether, further, in the above general formula (1), intended Rf ¹ is a perfluoro (alkoxyalkyl) group having 4 to 9 carbon atoms, Rf ¹ is represented by the following formula:

Wherein m is 0 or an integer of 1 to 4, and Rf ¹ is a group represented by the following formula:

(Wherein n represents an integer of 1 to 4), and the like.
The perfluoroalkylethylene is not particularly limited, and examples thereof include perfluorobutylethylene [PFBE], perfluorohexylethylene, (perfluorooctyl) ethylene, and the like.

As the fluorine-containing vinyl ether having a nitrile group, CF ₂ = CFORf ² CN (wherein Rf ² represents an alkylene group having 2 to 7 carbon atoms in which an oxygen atom may be inserted between two carbon atoms. ) Is more preferable.

The modified monomer in the modified PTFE is preferably at least one selected from the group consisting of HFP, CTFE, VDF, PPVE, PFBE, and ethylene. More preferably, it is at least one monomer selected from the group consisting of PPVE, HFP and CTFE.

The modified PTFE preferably has a modified monomer unit in the range of 0.001 to 2 mol%, and more preferably in the range of 0.001 to 1 mol%.

The PTFE preferably has a melt viscosity (MV) of 1.0 × 10 ² Pa · s or more, more preferably 1.0 × 10 ² Pa · s or more, and 1.0 × 10 ³ Pa · s. It is still more preferable that it is above.
The melt viscosity is in accordance with ASTM D 1238, and a 2 g sample that had been heated for 5 minutes at a measurement temperature (380 ° C.) in advance using a flow tester (manufactured by Shimadzu Corporation) and a 2φ-8L die was set to 0.000. The measurement can be performed while maintaining the above temperature with a load of 7 MPa.

The PTFE preferably has a standard specific gravity (SSG) of 2.130 to 2.230, more preferably 2.140 or more, and more preferably 2.190 or less.
In this specification, the standard specific gravity (SSG) can be measured based on an underwater substitution method in accordance with ASTM D 4895-89.

The PTFE preferably has a melting point of 324 to 360 ° C. In this specification, the melting point of the fluororesin is a value obtained as a temperature corresponding to the maximum value in the heat of fusion curve when the temperature is raised at a rate of 10 ° C./min using a differential scanning calorimetry (DSC) apparatus. .

Although it does not specifically limit as said PFA, The copolymer whose molar ratio (TFE unit / PAVE unit) of a TFE unit and a PAVE unit is 70/30 or more and less than 99/1 is preferable. A more preferable molar ratio is 70/30 or more and 98.9 / 1.1 or less, and a still more preferable molar ratio is 80/20 or more and 98.5 / 1.5 or less. When there are too few TFE units, there exists a tendency for a mechanical physical property to fall, and when too much, melting | fusing point becomes high too much and there exists a tendency for a moldability to fall. In the PFA, monomer units derived from monomers copolymerizable with TFE and PAVE are 0.1 to 10 mol%, and TFE units and PAVE units are 90 to 99.9 mol% in total. A copolymer is also preferred. As a monomer copolymerizable with TFE and PAVE, HFP, CZ ³ Z ⁴ = CZ ⁵ (CF ₂ ) nZ ⁶ (wherein Z ³ , Z ⁴ and Z ⁵ are the same or different and are each a hydrogen atom Or a fluorine atom, Z ⁶ represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer of 2 to 10, and a CF ₂ ═CF—OCH ₂ And an alkyl perfluorovinyl ether derivative represented by -Rf ⁷ (wherein Rf ⁷ represents a perfluoroalkyl group having 1 to 5 carbon atoms).

The PFA preferably has a melting point of 180 to 340 ° C, more preferably 230 to 330 ° C, and still more preferably 280 to 320 ° C.

The PFA preferably has a melt flow rate (MFR) of 0.1 to 100 g / 10 minutes, more preferably 0.5 to 90 g / 10 minutes, and 1.0 to 85 g / 10 minutes. More preferably.
In this specification, MFR is a value obtained by measuring at a temperature of 372 ° C. and a load of 5 kg in accordance with ASTM D 1238.

The PFA preferably has a standard specific gravity of 2.12 to 2.18.

Although it does not specifically limit as said FEP, The copolymer whose molar ratio (TFE unit / HFP unit) of a TFE unit and a HFP unit is 70/30 or more and less than 99/1 is preferable. A more preferable molar ratio is 70/30 or more and 98.9 / 1.1 or less, and a still more preferable molar ratio is 80/20 or more and 97/3 or less. When there are too few TFE units, there exists a tendency for a mechanical physical property to fall, and when too much, melting | fusing point becomes high too much and there exists a tendency for a moldability to fall. FEP has a monomer unit derived from a monomer copolymerizable with TFE and HFP in an amount of 0.1 to 10 mol%, and a total of 90 to 99.9 mol% of TFE units and HFP units. A polymer is also preferred. Examples of monomers copolymerizable with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.

The FEP preferably has a melting point of 150 to 320 ° C, more preferably 200 to 300 ° C, and still more preferably 240 to 280 ° C.

The FEP preferably has an MFR of 0.01 to 100 g / 10 minutes, more preferably 0.1 to 80 g / 10 minutes, still more preferably 1 to 60 g / 10 minutes. Particularly preferred is 50 g / 10 min.

The FEP preferably has a standard specific gravity of 2.12 to 2.18.

The ETFE is preferably a copolymer having a molar ratio of TFE units to ethylene units (TFE units / ethylene units) of 20/80 or more and 90/10 or less. A more preferable molar ratio is 37/63 or more and 85/15 or less, and a further preferable molar ratio is 38/62 or more and 80/20 or less. ETFE may be a copolymer composed of TFE, ethylene, and a monomer copolymerizable with TFE and ethylene. As a copolymerizable monomer, the following formula CH ₂ = CX ⁵ Rf ³ , CF ₂ = CFRf ³ , CF ₂ = CFORf ³ , CH ₂ = C (Rf ³ ) ₂
(Wherein, X ⁵ represents a hydrogen atom or a fluorine atom, and Rf ³ represents a fluoroalkyl group which may contain an ether bond), among which CF ₂ = CFRf ³ , A fluorine-containing vinyl monomer represented by CF ₂ = CFORf ³ and CH ₂ = CX ⁵ Rf ³ is preferred, and HFP, CF ₂ = CF-ORf ⁴ (wherein Rf ⁴ is a perfluoroalkyl having 1 to 5 carbon atoms) represents a group.) perfluoro represented by (alkyl vinyl ether) and Rf ³ is more preferably a fluorine-containing vinyl monomer represented by _CH 2 = ^CX 5 Rf ³ is a fluoroalkyl group having 1 to 8 carbon atoms. The monomer copolymerizable with TFE and ethylene may be an aliphatic unsaturated carboxylic acid such as itaconic acid or itaconic anhydride. The monomer copolymerizable with TFE and ethylene is preferably from 0.1 to 10 mol%, more preferably from 0.1 to 5 mol%, particularly preferably from 0.2 to 4 mol%, based on the fluoropolymer. preferable.

The ETFE preferably has a melting point of 140 to 340 ° C, more preferably 160 to 300 ° C, and still more preferably 195 to 275 ° C.

The ETFE preferably has an MFR of 1 to 100 g / 10 minutes, more preferably 2 to 50 g / 10 minutes, and still more preferably 4 to 40 g / 10 minutes.

The ETFE preferably has a standard specific gravity of 1.70 to 1.90.

In the present specification, the content of each monomer unit constituting the fluororesin can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.

The graphite yarn (A) has a crystallite size in the c-axis direction of 100 mm or less. The resin composition of the present invention uses the graphite yarn (A) having a specific crystallite size and the graphite yarn (B) in combination, so that the aluminum can be contacted with an aluminum article even when the wear coefficient is small. The surface of the manufactured article can be made difficult to be damaged. In the graphite yarn (A), the crystallite size in the c-axis direction is preferably 90 mm or less, and more preferably 60 mm or less. The lower limit of the crystallite size in the c-axis direction is not particularly limited, but is, for example, 10 mm.
The crystallite size in the c-axis direction is obtained by the Gakushin method using an X-ray diffractometer, measuring reflection from the (002) plane appearing in X-ray diffraction.
Specifically, the crystallite size in the c-axis direction is measured by X-ray diffraction measurement using an X-ray diffractometer (Rigaku, Ultima III), and the measurement substance is packed flat in a concave portion of a quartz sample holder. The X-ray source is set to Cu-Kα ray, the output is set to 40 kV, 20 mA, the reflection from the (002) plane appearing in the X-ray diffraction is measured, and it can be obtained by the Gakushin method.

The graphite yarn (A) is preferably other than pitch-based anisotropic graphite yarn. When the graphite yarn (A) is a graphite yarn other than the pitch-based anisotropic graphite yarn, a resin composition having a small wear coefficient can be obtained. Examples of the graphite yarn other than the pitch-based anisotropic graphite yarn include pitch-based isotropic graphite yarn, pitch-based isotropic carbon yarn, PAN-based carbon yarn, and PAN-based graphite yarn. Among these, although not particularly limited, pitch-based isotropic graphite yarn is more preferable.

The graphite yarn (A) preferably has an average fiber length of 5 to 1000 μm, more preferably 5 to 500 μm, from the viewpoint of maintaining mechanical strength and mixing with the resin. More preferably.
As for the average fiber length, a 200-magnification image of a scanning electron microscope is arbitrarily taken for 10 fields of view, 200 fiber lengths are measured, and a number average fiber length is obtained.

The graphite yarn (A) preferably has an average fiber diameter of 1 to 25 μm, more preferably 1 to 20 μm, from the viewpoint of maintaining mechanical strength and mixing with the resin. More preferably.
The average fiber diameter is obtained by arbitrarily photographing 10 field images of a scanning electron microscope for 10 fields of view, measuring the length of 200 fibers, and determining the number average fiber diameter.

The graphite yarn (A) has a half width of the diffraction peak of the (002) plane observed by X-ray diffraction and the (111) plane of standard silicon (NBS, 640) observed by X-ray diffraction under the same conditions. The half-value width ratio of the half-value width of the diffraction peak of (graphite yarn) / (standard silicon) standard silicon is preferably 10 or more. The half width ratio is more preferably 12 or more. When the half width ratio is in the above range, a resin composition that hardly damages the surface of the aluminum article when it comes into contact with the aluminum article can be obtained even if the wear coefficient is small.
The upper limit of the half width ratio is not particularly limited, but may be 100, for example.
The X-ray diffraction is measured by the same method as the crystallite size in the c-axis direction.

From the viewpoint of wear resistance, the graphite yarn (A) preferably has a specific gravity of 1.3 or more and less than 2.0, and more preferably 1.4 to 1.9. The specific gravity can be determined according to the butanol substitution method (JIS R 7222).

Examples of the graphite yarn (A) include Kureha Corporation Kureka Chop M2007S (crystallite size: 16.5 mm), M-201S (crystallite size: 17.4 mm), M-207S, M-1009S, M-101S, Donakabo SC249 (crystallite size: 13.9 mm), SG-249 (crystallite size: 17.6 mm), SC-2404N (crystallite size: 13.9 mm), SG manufactured by Osaka Gas Chemical Co., Ltd. -2404N (crystallite size: 20.1 mm), Tenax HTC443 6MM (crystallite size: 14.1 mm) manufactured by Toho Tenax Co., Ltd., HTM800 160 mu, HTM100 40 mu, MLD manufactured by Toray Industries, Inc., and the like.

The graphite yarn (B) has a crystallite size in the c-axis direction of more than 100 mm. The resin composition of the present invention uses the graphite yarn (A) having a specific crystallite size and the graphite yarn (B) in combination, so that the aluminum can be contacted with an aluminum article even when the wear coefficient is small. The surface of the manufactured article can be made difficult to be damaged. In the graphite yarn (B), the crystallite size in the c-axis direction is preferably 120 mm or more, and more preferably 140 mm or more. The upper limit of the crystallite size in the c-axis direction is not particularly limited, but is, for example, 500 mm. The crystallite size in the c-axis direction is determined by the same method as for the graphite yarn (A).

The graphite yarn (B) is preferably a pitch-based anisotropic graphite yarn. When the graphite yarn (B) is a pitch-based anisotropic graphite yarn, the surface of the aluminum article can be hardly damaged when it comes into contact with the aluminum article.

The graphite yarn (B) has a half-value width of the diffraction peak of the (002) plane observed by X-ray diffraction and a half of the diffraction peak of the (111) plane of standard silicon observed by X-ray diffraction under the same conditions. It is preferable that the half width ratio of the full width at half width (graphite yarn) / (standard silicon) to standard silicon is less than 10. More preferably, it is 7 or less.
The lower limit of the half width ratio is not particularly limited, but may be 1, for example.
The X-ray diffraction is measured by the same method as the crystal size in the c-axis direction.

The graphite yarn (B) preferably has an average fiber length of 5 to 1000 μm, more preferably 5 to 500 μm, from the viewpoint of maintaining mechanical strength and mixing with the resin. More preferably.
The average fiber length was obtained by arbitrarily photographing 10-fold images of a scanning electron microscope for 10 fields of view, measuring the length of 200 fibers, and obtaining the number average fiber length.

The graphite yarn (B) preferably has an average fiber diameter of 1 to 25 μm, more preferably 1 to 20 μm, from the viewpoint of maintaining mechanical strength and miscibility with the resin. More preferably.
As for the average fiber diameter, 200-magnification images of a scanning electron microscope were arbitrarily taken for 10 fields of view, 200 fiber diameters were measured, and the number average fiber diameter was obtained.

The graphite yarn (B) preferably has a specific gravity of 2.0 to 2.4, more preferably 2.0 to 2.3, from the viewpoint of attacking the counterpart material.
The specific gravity can be determined according to the butanol substitution method (JIS R 7222).

Examples of the graphite yarn (B) include XN-100-05M (crystallite size: 234.0 mm), XN-100-10M, and XN-100-15M (crystallite size: 243) manufactured by Nippon Graphite Fiber Co., Ltd. .8 cm), HC-600-15M (crystallite size: 230.7 mm), ZY-300-15M (crystallite size: 312.9 mm), K223HM manufactured by Mitsubishi Rayon Co., Ltd. (crystallite size: 211.0 cm) , K6331M (crystallite size: 130.6 Å) and the like.

In the resin composition of the present invention, the total content of the graphite yarn (A) and the graphite yarn (B) is preferably 3 to 40% by mass with respect to the resin composition. If it is less than 3% by mass, the filler filling effect may not be exhibited. If it exceeds 40% by mass, mechanical properties tend to be remarkably lowered.

In the resin composition of the present invention, the mass ratio (A / B) of the content of the graphite yarn (A) and the graphite yarn (B) is 1.0 / 9.0 to 9.9 / 0.1. Is preferred. More preferably, it is 3.0 / 7.0 to 9.9 / 0.1. By setting the mass ratio (A / B) to 3.0 / 7.0 or more, the wear resistance is further improved. This factor is considered to be because the amount of graphite yarn (B) having a high wear coefficient and heat dissipation having a crystallite size in the c-axis direction exceeding 100 mm was controlled.
In particular, from the viewpoint of excellent wear resistance, the mass ratio (A / B) is preferably 7.0 / 3.0 to 9.9 / 0.1.

The resin composition of the present invention preferably contains a graphite yarn (A) that is other than the pitch-based anisotropic graphite yarn and a graphite yarn (B) that is the pitch-based anisotropic graphite yarn. By using both pitch-based anisotropic graphite yarn and pitch-based anisotropic graphite yarn in combination, a resin composition that hardly damages the surface of an aluminum article even when the wear coefficient is small is in contact with the aluminum article. can get.

The resin composition of the present invention may be composed only of a heat resistant resin and graphite yarns (A) and (B), but is necessary in addition to the heat resistant resin and graphite yarns (A) and (B). Depending on the above, other components may be included. In addition to the above-mentioned other components, various additives such as metal, inorganic or organic reinforcing fillers, compatibilizers, lubricants (carbon fluoride, carbon graphite, molybdenum disulfide), stabilizers, and the like may be combined. Can do.
It is preferable that said other component is 50 mass% or less of a resin composition. More preferably, it is 40 mass% or less.

The resin composition of the present invention can be produced by a known method. For example, heat-resistant resin, graphite yarn (A) and graphite yarn (B), and other components added as necessary, such as V-type blender, tumbler, Henschel mixer, ball mixer, Redige mixer, etc. You may obtain by mixing with a mixer, Furthermore, you may knead | mix and knead the obtained mixture using melt-kneading apparatuses, such as a single screw extruder and a twin screw extruder. A method of supplying the graphite yarns (A) and (B) to the heat resistant resin melted in the melt kneading apparatus in the middle is also possible.

The resin composition of the present invention has excellent sliding properties and can be used as a sliding material that can be used in a high temperature and high heat generation environment. Examples of the products including the sliding material include various gears, sliding friction or rolling friction mechanism bearings, bearings, brakes, clutch parts, piston rings, various seal members, and the like. Suitable applications include seal rings used in various hydraulic devices such as automobile automatic transmissions and continuously variable transmissions. That is, the present invention is also a seal ring formed by molding the resin composition. In particular, a seal ring used in contact with an aluminum article is preferable. The seal ring is particularly useful as a seal ring for automobiles, particularly as a seal ring for automobile automatic transmissions.
The seal ring can be formed by a usual method according to the heat-resistant resin used. Examples of the molding method include injection molding, extrusion molding, and compression molding.
When PTFE is used as the heat resistant resin, PTFE, graphite yarns (A) and (B) are mixed with the above mixer to obtain a resin composition, and then molded by a molding method such as compression molding. After firing at 350 to 380 ° C. for 0.5 to 10 hours, the obtained fired body may be processed by cutting or the like to obtain a desired molded body (such as a seal ring).

In addition, compressor seals (chip seals, piston rings), high-pressure seals for high-rise buildings, trucks, buses, automobiles, and other power steering systems that use carbon dioxide, natural gas, alternative chlorofluorocarbon, air, helium gas, etc. It can also be used as a seal bearing for construction machines such as seal rings, excavators, forklifts, bulldozers or nailers.

Next, the present invention will be described with reference to experimental examples, but the present invention is not limited to such experimental examples.

The raw material compounds used in the experimental examples will be described.

(1) Base polymer (heat resistant resin)
Polytetrafluoroethylene (PTFE), trade name: Polyflon M-18F, manufactured by Daikin Industries, Ltd., standard specific gravity (SSG): 2.164, melting point: 344.9 ° C.
(2) Pitch-based anisotropic graphite yarn Product name: GRANOC, Grade: XN-100-15M, manufactured by Nippon Graphite Fiber Co., Ltd., half-value width ratio with standard silicon: 3, crystallite size in the c-axis direction 244Å
(3) Pitch-based isotropic graphite yarn Product name: Kureka chop, grade: M2007S, manufactured by Kureha Co., Ltd., half-value width ratio with standard silicon: 46, crystallite size in the c-axis direction 17 mm
The SSG and melting point of the PTFE, the half width ratio of the graphite yarns (A) and (B) with the standard silicon, and the crystallite size in the c-axis direction are values obtained by the above-described method.

Various measurement methods of characteristics evaluated in experimental examples will be described.

80 g of each of the resin compositions of wear coefficient examples 1 to 8 and comparative examples 1 to 2 was pressure-molded at a molding pressure of 68.6 MPa and then fired at 370 ° C. to form a cylindrical molded body (outer diameter 30 mm, height 50 mm). ) A test piece for measuring the wear coefficient (outer diameter 25.6 mm, inner diameter 20 mm, height 15 mm) was prepared from this molded body, and a friction wear tester MODEL EFM-III-F / ADX manufactured by Orientec Co., Ltd. was used. Load: 0.45 MPa
Speed: 1.0m / s
Temperature: Room temperature Partner: Aluminum die-cast ADC12
Opposite material surface roughness: Ra 0.6 μm
Friction and wear tests were conducted under the conditions described above, and the wear coefficient was calculated from the change in the test piece weight before and after the test.

Relative material surface roughness change rate (%)
The rate of change in surface roughness of the mating material was calculated by the following equation: surface roughness of the mating material sliding surface before the frictional wear test (before Ra) and mating material sliding surface surface roughness after the test (after Ra).
Relative material surface roughness change rate (%) = (after Ra-before Ra) × 100 / Ra The surface roughness of the mating material sliding surface after the pre-test is 3 hours in the electric furnace at 410 ° C. after the test. By heating and allowing to cool in a desiccator for 2 hours, the sliding surface of this mating material is measured according to JIS B 0601-1994 using a surface roughness measuring machine SURFTEST SV-600 manufactured by Mitutoyo. Obtained.

Comparative Example 1
90 parts by mass of polytetrafluoroethylene resin powder (Polyflon PTFE M-18F, manufactured by Daikin Industries, Ltd.) obtained by suspension polymerization, and pitch-based anisotropic graphite yarn (GRANOC XN-100-15M) as a filler, 10 parts by mass of Nippon Graphite Fiber Co., Ltd.) was mixed using a Henschel mixer to obtain a polytetrafluoroethylene composition.

Example 1
90 parts by mass of polytetrafluoroethylene resin powder (Polyflon PTFE M-18F, manufactured by Daikin Industries, Ltd.) obtained by suspension polymerization, and pitch-based anisotropic graphite yarn (GRANOC XN-100-15M) as a filler, 9 parts by mass of Nippon Graphite Fiber Co., Ltd. and 1 part by mass of pitch-based isotropic graphite yarn (Kureka Chop M2007S, Kureha Co., Ltd.) were mixed using a Henschel mixer to obtain a polytetrafluoroethylene composition. .

Example 2 to Example 8
In the same manner as in Example 1, the blending amounts shown in Table 1 were mixed.

Comparative Example 2
90 parts by mass of polytetrafluoroethylene resin powder (polyflon PTFE M-18F, manufactured by Daikin Industries, Ltd.) obtained by suspension polymerization, and pitch-based isotropic graphite yarn (Kureka Chop M2007S, Kureha Co., Ltd.) as a filler 10 parts by mass) were mixed using a Henschel mixer to obtain a polytetrafluoroethylene composition.

As can be seen from the results of Examples 1 to 8, the wear coefficient is reduced by using a graphite thread having a crystallite size in the c-axis direction of 100 mm or less and a graphite thread having a crystallite size in the c-axis direction exceeding 100 mm. When it comes into contact with an aluminum article, a molded body that hardly damages the surface of the aluminum article is obtained.
For example, in Examples 1 to 4, it can be seen that the wear coefficient can be reduced without increasing the mating material surface roughness change rate as compared with Comparative Example 1.
Further, in Examples 5 to 8, although the rate of change in the surface roughness of the counterpart material is equivalent to that of Comparative Example 2, a molded product having a small wear coefficient compared to either Comparative Example 1 or Comparative Example 2 is obtained. It can be seen that the effect of combining the graphite yarn having a crystallite size in the c-axis direction of 100 mm or less and the graphite yarn having a crystallite size in the c-axis direction of more than 100 mm is sufficiently exerted.

Claims

Heat resistant resin,
a graphite thread (A) having a crystallite size in the c-axis direction of 100 mm or less, and
Graphite yarn with crystallite size in the c-axis direction exceeding 100 mm (B)
The resin composition characterized by including.
The resin composition according to claim 1, wherein the total content of the graphite yarn (A) and the graphite yarn (B) is 3 to 40% by mass with respect to the resin composition.
The resin composition according to claim 1 or 2, wherein the mass ratio (A / B) of the content of the graphite yarn (A) and the graphite yarn (B) is 1.0 / 9.0 to 9.9 / 0.1. object.
The resin composition according to claim 1, 2 or 3, wherein the graphite yarn (A) is other than pitch-based anisotropic graphite yarn.
The resin composition according to claim 1, wherein the graphite yarn (B) is a pitch-based anisotropic graphite yarn.
The resin composition according to claim 1, wherein the heat-resistant resin is at least one selected from the group consisting of a fluororesin, a polyetherketone resin, a polyarylene sulfide resin, and a phenol resin. object.