JPH05117477A - Molten fluororesin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition which shows excellent sliding properties even when used with a soft material in sliding contact therewith, particularly even under high-speed and high-load conditions, has heat resistance, chemical resistance, dimensional stability, and excellent mechanical characteristics which are required of the material of sliding parts, and can be injection molded with excellent productivity. CONSTITUTION:A molten fluororesin composition which consists of 100 pts.wt. molten fluororesin that can be injection molded, 5-50 pts.wt. carbon fibers, and 5-50 pts.wt. mixture of 90-10wt.% polytetrafluoroethylene with 10-90wt.% solid lubricant.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fluorine-containing molten resin composition. The composition of the present invention is a sliding component material, in particular,
It is suitable as a material for sliding parts made of soft metals or soft alloys.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As a material used for sliding parts of machines such as hydraulic or pneumatic equipment and compressors, a tetrafluoroethylene polymer composition containing an inorganic or organic filler for the purpose of improving creep resistance, wear resistance, etc. As is known, it cannot be said that the improvement in dimensional stability and creep resistance due to the filler has been sufficiently achieved. Further, this composition has a drawback that it cannot be injection-molded, resulting in poor productivity and unfavorable in manufacturing cost.

Compositions prepared by incorporating various solid lubricants and reinforcing materials into a heat-resistant resin capable of being injection-molded for the purpose of slidability or strengthening have been proposed. In the above tetrafluoroethylene polymer composition, In comparison, in applications in which the sliding property is inferior and the sealing property is required at the same time, these compositions may have too high rigidity to obtain sufficient sealing property.

On the other hand, in recent years, soft materials such as aluminum alloys have been widely used as the weight of various devices has been reduced. When these materials are used as mating materials, conventional materials such as those mentioned above are used during sliding. A composition that has the problem of damaging the mating material and that satisfies the slidability and other properties even in applications where higher slidability is required, such as when used under high speed and high load Was not obtained.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to solve the above-mentioned object, as a result, a carbon fiber was added to a fluorine-containing molten resin for the purpose of improving slidability and dimensional stability. It has been found that, when a solid lubricant and PTFE powder having excellent affinity with a fluorine-containing molten resin are added together in order to further improve the slidability, a superior effect is obtained as compared with the case where they are added alone. It came to complete the invention.

That is, the gist of the present invention consists of an injection-moldable fluorine-containing molten resin (a), carbon fiber (b), and 90 to 10% by weight of polytetrafluoroethylene and 10 to 90% by weight of a solid lubricant. A fluorine-containing molten resin composition comprising the mixture (c) and containing 5 to 50 parts by weight of the component (b) and 5 to 50 parts by weight of the component (c) per 100 parts by weight of the component (a).

Fluorine-containing molten resin (a) capable of injection molding
Is a tetrafluoroethylene / fluoroalkyl vinyl ether copolymer (hereinafter referred to as PFA), a tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter referred to as FEP), a tetrafluoroethylene / ethylene copolymer (hereinafter referred to as ETFE) , Polyvinylidene fluoride (hereinafter referred to as PVDF), polychlorotrifluoroethylene (hereinafter referred to as PCTFE), and the like are preferable. PF in terms of heat resistance, sliding properties, moldability, etc.
A and FEP are particularly preferable. The molecular weight of the fluorinated molten resin (a) is preferably 50,000 to 5,000,000.

PFA has the formula: tetrafluoroethylene and the formula:
It is at least one copolymer of a fluoroalkyl vinyl ether represented by CF ₂ ═CF—O—R _f (wherein R _f represents a fluoroalkyl group having 1 to 10 carbon atoms). The fluoroalkyl vinyl ether is preferably a perfluoroalkyl vinyl ether. PFA is preferably composed of 99.5 to 92% by weight of tetrafluoroethylene and 0.5 to 8% by weight of fluoroalkyl vinyl ether. In addition, FEP is tetrafluoroethylene 96
˜87 wt% and hexafluoropropylene 4 to 13 wt% are preferred. ETFE is tetrafluoroethylene 89.3 to 74.5% by weight and ethylene 10.7 to
It preferably comprises 25.5% by weight.

These fluorine-containing molten resins may contain other monomers as long as the essential properties of these polymers are not impaired. Other monomers include tetrafluoroethylene (excluding PFA, FEP, ETFE), hexafluoropropylene (excluding FEP), perfluoroalkyl vinyl ether (excluding PFA), perfluoroalkyl (having 1 to 10 carbon atoms). Ethylene, perfluoroalkyl (C1-10) allyl ether,
And the formula: CF ₂ ═CF [OCF ₂ CFX (CF ₂ ) _m ] _n OCF ₂ (CF ₂ ) _o Y (wherein X is a fluorine or trifluoromethyl group, Y is a halogen, and m is a number of 0 or 1 ( However, when m is 1,
X is limited to fluorine), n is a number from 0 to 5, and o is a number from 0 to 2). The amount of other monomers is not more than 50% by weight of the polymer, preferably 0.01.
~ 45% by weight.

The carbon fiber (b) has dimensional stability, reinforcing property,
It is added for the purpose of improving abrasion resistance and creep resistance. Carbon fibers have an average fiber length of 50 to 50 when molded into sliding parts after being mixed with other components.
It is preferable that the aspect ratio is 600 μm and the aspect ratio is 8 to 300. Carbon fibers should be selected with consideration of the fact that the fibers will break during mixing and molding. Carbon fiber
Before mixing, it is desirable that the average fiber length is 20 to 1000 μm and the aspect ratio is 3 to 300. Examples of carbon fibers include Toray Industries, Inc .; Trading Card MLD-70, Kureha Chemical Industry Co., Ltd .; Creca M2007S, M201S and M207S.

Mixture (c) consists of 90 to 10% by weight of polytetrafluoroethylene and 10 to 90% by weight of solid lubricant. In order to achieve good flow characteristics during molding of the composition of the present invention, it is preferable that the mixture (c) is a mixture of polytetrafluoroethylene and a solid lubricant that has been mixed in advance by a co-coagulation method. .. The solid lubricant may be mixed with the emulsified dispersion of polytetrafluoroethylene and then premixed by a method such as co-coagulation by an appropriate method. The dispersion medium of the emulsified dispersion is, for example, water or an organic solvent. Co-coagulation includes, for example, mixing an aqueous dispersion of polytetrafluoroethylene with an aqueous dispersion of a solid lubricant powder emulsified with an emulsifier such as ammonium perfluorooctanoate, and adding aluminum sulfate or the like while sufficiently stirring. This can be done by adding a coagulant.

The polytetrafluoroethylene used in the mixture (c) is preferably a powder having an average particle size of 30 μm or less or an emulsified dispersion having an average dispersed particle size of 30 μm or less. The lower limit of the average particle size is preferably 0.01 μm. Polytetrafluoroethylene powder generally added for the purpose of imparting slidability, for example, Daikin Industries Ltd .; Lubron L-2, L-5, L-5F, Mitsui DuPont Fluorochemicals Ltd .; TLP-10, TLP.
10F-1, manufactured by Asahi Glass Co., Ltd .; FLUON L-169,
L-170, L-171, manufactured by Hoechst; Hostafuron TF-9202, TF-9205, manufactured by Central Glass Co., Ltd .; Cefrallube I, Ip, manufactured by Kitamura Co., Ltd .;
KTL-450, KTL-610, KTL-500F,
KTL-400M or the like can be used. Moreover, polytetrafluoroethylene powder for molding, for example, manufactured by Daikin Industries, Ltd .; Polyflon M-12, M-15, M-
24, F-104, F-201, manufactured by Mitsui DuPont Fluorochemical Co., Ltd .; Teflon 7-J, 7A-J, 914.
-J, 6-J, 62-J, 6C-J, manufactured by Asahi Glass Co., Ltd .; Fluon G-163, G-190, G-201, C
D-1, CD-123, CD-4, Hoechst Co .; Hostaflon TF-1400, TF-1740, TF-11
01, TF-2021, TF-2053 and the like can also be used.

The polytetrafluoroethylene powder also includes a polymer obtained by copolymerizing tetrafluoroethylene with not more than 1.0% by weight of a monomer copolymerizable therewith. Examples of solid lubricants include layered structures such as molybdenum disulfide, graphite, tungsten disulfide, boron nitride, tungsten diselenide, and graphite fluoride. Among these, molybdenum disulfide and graphite are particularly preferable because they have smaller friction coefficient and wear coefficient than fluorinated graphite.

In the composition of the present invention, carbon fiber (b)
Is 5 to 50 parts by weight based on 100 parts by weight of the fluorine-containing molten resin (a). If the carbon fiber content is less than 5 parts by weight, little improvement in wear resistance and dimensional stability can be expected. Further, if it exceeds 50 parts by weight, the mechanical strength is lowered.
In the composition of the present invention, the amount of the mixture (c) is 5 to 50 parts by weight based on 100 parts by weight of the fluorine-containing molten resin (a). If the amount of mixture (c) is less than 5 parts by weight,
The friction coefficient and the wear coefficient cannot be sufficiently lowered, and if it exceeds 50 parts by weight, the mechanical strength and the dimensional stability are significantly lowered.

Further, when the amounts of the polytetrafluoroethylene powder and the solid lubricant in the mixture (c) are out of the above ranges, the friction coefficient and the wear coefficient cannot be sufficiently lowered, and the object of the present invention is to be obtained. Cannot be fully achieved.

The composition of the present invention may contain at least one inorganic or organic reinforcing material and one or more commonly used additives as long as the object of the present invention is not impaired.

In preparing the resin composition used in the present invention, a commonly known mixing method is adopted. For example, after mixing the respective components with a mixer such as a V-type blender, a tumbler or a Henschel mixer, the mixture is further mixed. You may mix and pelletize using a melt-kneading apparatus, such as a shaft extruder.

After preparing a premix of the solid lubricant and polytetrafluoroethylene, it is preferred to mix this mixture with the other ingredients in the manner described above.

The pellets thus obtained are molded by a commonly used thermoplastic resin molding machine such as an injection molding machine.
A molded product having a desired shape, for example, a plate-shaped body or a film can be molded by a compression molding machine, an extrusion molding machine or the like. It is desirable to adopt injection molding in order to obtain the sliding part material with good productivity.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The resin compositions obtained in Examples and Comparative Examples were evaluated by the following test methods.

Test Method: Friction and Wear Test Using a Suzuki Matsubara type friction and wear tester manufactured by Orientec Co., Ltd., an Al alloy die casting (JIS H5
ADC12 specified in 302) (surface roughness Ra =
0.3-0.6 μm) was used. Dynamic friction coefficient is 5
(Kgf / cm ² ) and the speed was 140 (m / min). Wear coefficient is 5 (kgf / cm ² ) of surface pressure and 140
After conducting a test for 1.1 hours (traveling distance 10 km) at (m / min), the decrease in the weight of the test piece was measured and calculated by the following formula. Wear coefficient (mm ³ / kgf ・ km) = wear weight (mg) / (mileage (km)
× Surface pressure (kgf / cm ² ) × Contact area (cm ² ) × Density (mg / mm ³ )) Tensile test Using a Tensilon universal tester manufactured by Orientec Co., Ltd., according to ASTM D638, at room temperature at a pulling speed of 5
The tensile breaking strength was measured at mm / min. ASTM D using a melt indexer manufactured by MFR Toyo Seiki Co., Ltd.
According to 1238, die diameter 2.095mm, length 8mm,
The MFR (g / 10 minutes) at 372 ° C. was measured under a load of 5 kg.

Example 1 Tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer powder (manufactured by Daikin Industries, Ltd .; NEOFLON PFA AP201) and carbon fiber (manufactured by Kureha Chemical Industry Co., Ltd .; Creca M207S, average fiber length 700 μ)
m, aspect ratio 50), and molybdenum disulfide, polytetrafluoroethylene powder (manufactured by Daikin Industries, Ltd .; Lubron L-5F, particle size 5 μm) were uniformly mixed in advance with a Henschel mixer at a ratio shown in Table 1.
34 using a twin-screw extruder with a screw diameter of 25 mm
The mixture was melt mixed at 0 to 380 ° C. and pelletized. The pellets thus obtained were injected into an injection molding machine (cylinder temperature 340
˜380 ° C., mold temperature 140 ° C.), and each test piece was molded. The physical properties of these test pieces were measured by the above-mentioned test methods. The results obtained are shown in Table 1.

Example 2 Molybdenum disulfide was used as a solid lubricant, and the same amount of polytetrafluoroethylene was added to an emulsion dispersion of polytetrafluoroethylene powder for addition (Daikin Industries Co., Ltd .; Lubron L-5F). A small amount of aluminum sulfate was added as a coagulant with stirring to obtain a co-coagulated product of polytetrafluoroethylene and molybdenum disulfide. After sufficiently drying this, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer powder (manufactured by Daikin Industries, Ltd .; NEOFLON PFA AP201)
And carbon fiber (Kureha Chemical Industry Co., Ltd .; Creca M207
S) and the ratio shown in Table 1 in the same procedure as in Example 1,
It was molded and the physical properties were measured. The results obtained are shown in Table 1.

Example 3 The same procedure as in Example 1 was repeated except that polytetrafluoroethylene powder for general molding (manufactured by Daikin Industries, Ltd .; Polyflon M-12, particle size 25 μm) was used as the polytetrafluoroethylene powder. .. The results obtained are shown in Table 1.

Example 4 The same procedure as in Example 1 was repeated except that graphite was used as the solid lubricant. The results obtained are shown in Table 1.

Example 5 The same procedure as in Example 1 was repeated except that fluorinated graphite was used as the solid lubricant. The results obtained are shown in Table 1.

Comparative Examples 1, 2 and 3 The same procedure as in Example 1 was repeated except that either solid lubricant or polytetrafluoroethylene powder was used. The results obtained are shown in Table 2.

Comparative Example 4 The same procedure as in Example 1 was repeated except that neither solid lubricant nor polytetrafluoroethylene powder was used. The results obtained are shown in Table 2.

Comparative Example 5 Polytetrafluoroethylene powder (manufactured by Daikin Industries, Ltd .;
Polyflon M-12) and carbon fibers were mixed in a Henschel mixer at a ratio shown in Table 2 and filled in a mold,
After pre-pressurizing at 300 kgf / cm ² for 5 minutes, it was taken out of the mold, placed in an electric furnace, and baked at 380 ° C. for 30 minutes. A test piece was produced from the fired body by cutting and the physical properties were measured. The results obtained are shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

As is clear from Tables 1 and 2, the resin composition of the present invention has a low coefficient of friction and a low coefficient of wear, which are required as materials for sliding parts, and is shown in Comparative Examples 1, 2, and 3. , The solid lubricant and the polytetrafluoroethylene powder each have a better effect than the case where they are individually added.

Particularly, as in Example 2, the solid lubricant and the polytetrafluoroethylene powder were premixed by the co-coagulation method and then the mixture was filled. Further, it can be seen that the composition of the present invention is superior in slidability to the filled tetrafluoroethylene as in Comparative Example 6.

[0034]

EFFECTS OF THE INVENTION The resin composition of the present invention exhibits excellent slidability even when used with a soft material as a mating material, particularly when used under high speed and high load. Further, it has heat resistance, chemical resistance, dimensional stability, and excellent mechanical properties required as a material for sliding parts. Moreover, it can be molded by injection molding with excellent productivity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // (C08L 27/12 27:18) B29K 27:12 (72) Inventor Masami Kato Settsu, Osaka Prefecture Daiichi Kogyo Co., Ltd. 1-1 Daikin Kogyo Co., Ltd. Yodogawa Works (72) Inventor Tsuyoshi Miyamori 1-1 Settsu Nishi-City, Osaka Prefectural Daiichi Kogyo Co., Ltd. Yodogawa Works (72) Inventor Tetsuo Shimizu Osaka Pref. No. 1 Ichitsuya Daikin Industrial Co., Ltd. Yodogawa Works

Claims (5)

[Claims] 1. An injection-moldable fluorine-containing molten resin (a), carbon fiber (b), and polytetrafluoroethylene of 90 to 10% by weight and a solid lubricant of 10 to 90% by weight.
5 to 50 parts by weight of component (b) and 5 to 50 parts by weight of component (c) per 100 parts by weight of component (a).
A fluorine-containing molten resin composition containing 50 parts by weight. 2. The average fiber length of carbon fibers is 20 to 1000.
The composition according to claim 1, which has a micrometer and an aspect ratio of 3 to 300. 3. The fluorine-containing molten resin is a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer,
The composition according to claim 1 or 2, which is a tetrafluoroethylene / hexafluoropropylene copolymer. 4. The composition according to claim 1, wherein the solid lubricant is molybdenum disulfide or graphite. 5. The composition according to claim 1, wherein the component (c) is premixed by a co-coagulation method.