JPH0885758A - Heat-resistant lubricating resin composition - Google Patents

Abstract

PURPOSE: To obtain a heat-resistant lubricating resin composition having low frictional properties, excellent wear resistance and the property of not attacking a soft alloy and being applicable to a slide bearing by using a polyphenylene sulfide resin. CONSTITUTION: This resin composition essentially consists of a polyphenylene sulfide resin as a base, 5-40vol.% fluororesin, 3-25vol.% aromatic polyester resin and 2-20vol.% para-oriented aromatic polymide fibers. Examples of the fluororesins which can be adopted include an ethylene/tetrafluoroethylene copolymer and a tetrafluoroethylene/hexafluoropropylene copolymer. Alternatively, it may be a mixture of polytetrafluoroethylene with a tetrafluoroethylene/ hexafluoropropylene copolymer. When aromatic polyamide fibers other than the para-oriented ones are used, a similar composition can be obtained by using 18-38vol.% tetrafluoroethylene resin as the fluororesin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant / lubricating resin composition used as various sliding members and a heat-resistant sliding bearing, and particularly to heat-resistant / lubricating properties applicable to a heat fixing device of an electrophotographic apparatus. The present invention relates to a resin composition and a heat resistant plain bearing.

[0002]

2. Description of the Related Art In recent years, as the field of application of synthetic resin slide bearings has expanded, heat resistant synthetic resin slides that exhibit good friction and wear characteristics under bearing operating conditions, especially in high temperature atmospheres, have been developed. Bearings have been strongly demanded.

Further, when an aluminum alloy or the like is used as a sliding mating material of the bearing, the bearing is required to have a property of not damaging a relatively soft sliding mating material during use. Specific examples of heat resistant plain bearings that require the above characteristics include:
Bearings for heat fixing devices such as copiers and laser beam printers can be mentioned.

The general usage of such a slide bearing will be described below. That is, a copying machine or a laser beam printer having a mechanism for transmitting information of an original image to a transfer material which is a recording material by using a charged image is generally referred to as an electrophotographic apparatus. As illustrated in FIG. 3, a heating roller 10 that heat-fixes the toner image on the transfer material, and a pressure roller 11 that presses the transfer material against the heating roller 10 to rotate the transfer material are mounted.

The former heating roller 10 is often made of an aluminum alloy containing Mg, and is heated by the heater 12 to a temperature of about 150 to 230 ° C. The latter pressure roller 11 is made of an iron material coated with silicone rubber or the like.
Heat to 0-150 ° C.

FIG. 4 shows a fixing device having a mechanism different from that of the above-mentioned heat fixing device. Instead of a metal heating roller, a heat-resistant synthetic resin film is coated with a release agent to form an endless material. An annular fixing film 15 is used, and the ceramic heater 16 is pressed against the pressure roller 11 via the fixing film 15 to improve heat conduction efficiency. In this case, the pressure roller 11 becomes even hotter than that of the fixing device using the metal heating roller 10 described above.

As described above, the ends of the rollers used at high temperatures are supported by the synthetic resin sliding bearings 13 and 14 (bearings corresponding to 14 in the apparatus of FIG. 4). , Polyphenylene sulfide (hereinafter, PP), which is a thermoplastic synthetic resin having good heat resistance and excellent mechanical strength.
A resin (abbreviated as S) is used. In this case, since the PPS resin has a poor self-lubricating property, a composition containing a lubricant such as graphite, tetrafluoroethylene resin, lubricating oil, metal oxide, aromatic polyamide resin, etc. is often used.

However, the conventional PPS resin heat resistant / lubricating composition described above has a problem in that it cannot maintain a low friction coefficient under high temperature and high load conditions, and cannot sufficiently exhibit wear resistance. is there.

Further, a resin composition has been developed in which a heat-resistant synthetic resin powder and a tetrafluoroethylene resin are added to the PPS resin. As a typical example,
It is a composition containing an aromatic polyester resin and is disclosed in JP-A-57-167348 and JP-A-63-17506.
No. 5 is disclosed. These compositions exhibit good wear resistance at relatively low temperatures.

[0010]

However, the composition in which the tetrafluoroethylene resin and the aromatic polyester resin are uniformly mixed with the PPS resin damages the sliding partner material at a high temperature condition when it is an aluminum alloy. At the same time, there is a problem that the wear itself.

When carbon fiber is added to such a composition, a soft aluminum alloy, which is a sliding partner, may be damaged, and the friction and wear characteristics may be deteriorated due to the damage.

Further, as sliding mating materials, Mg and Si, which are harder than aluminum alloys containing Mg, are used.
Under the sliding condition in which the aluminum alloy containing is adopted, the low friction property, the wear resistance of the resin composition contacting the aluminum alloy,
There is also a problem that it is extremely difficult to satisfy all the damage properties of the sliding counterpart material.

Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a heat-resistant / lubricating resin composition with lower friction characteristics, wear resistance and aluminum than those of conventional compositions containing PPS as a main material. It has non-aggressiveness against soft alloys such as alloys. Furthermore, not only an aluminum alloy containing Mg but also an aluminum alloy containing Mg and Si as a sliding partner can obtain the above good results. It is to be applicable to heat-resistant plain bearings with high performance.

[0014]

In order to solve the above problems, in the present invention, a polyphenylene sulfide resin is used as a main component, and a fluororesin is contained in an amount of 5 to 40% by volume.
The heat-resistant and lubricating resin composition was obtained by adding 3 to 25% by volume of the aromatic polyester resin and 2 to 20% by volume of the para-type aromatic polyamide fiber as an essential component. As the fluororesin, an ethylene-tetrafluoroethylene copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer can be adopted. Alternatively, the fluororesin may be a mixture of polytetrafluoroethylene and a tetrafluoroethylene-hexafluoropropylene copolymer.

Further, as the para-aromatic polyamide fiber, a para-aromatic polyamide fiber containing a repeating unit represented by the following chemical formula 3 can be adopted.

[0016]

[Chemical 3]

Polyphenylene sulfide resin as a main component, 18 to 38% by volume of tetrafluoroethylene resin, 3 to 25% by volume of aromatic polyester resin, and 2 to 20% by volume of aromatic polyamide fiber are added as essential components. The heat-resistant / lubricating resin composition was prepared.

As the aromatic polyester resin, a resin containing a repeating unit represented by the following chemical formula 4 can be adopted.

[0019]

[Chemical 4]

Alternatively, the above heat resistant / lubricating resin composition is molded into a heat resistant plain bearing.

[0021]

The heat-resistant / lubricating resin composition of the present invention comprises a PPS resin having excellent heat resistance as a main component, and an aromatic polyester resin having a large limit PV value is added to the composition, and a fluororesin having excellent slidability. Since it is added in a predetermined amount, it has required heat resistance, slidability and mechanical properties. Also,
Since PPS resin is the main component, injection molding is possible.

The para-aromatic polyamide fiber added to such a composition has high elasticity and high strength in the axial direction because the molecular chains are arranged in the axial direction of the fiber, but the molecular weight is increased in the perpendicular direction. The force is weak. Therefore, the para-aromatic polyamide fiber improves the abrasion resistance of the resin composition blended by the strength in the axial direction, but when compressed in the perpendicular direction, the molecular chain is likely to buckle, so that a soft sliding partner It is considered that the material is not damaged.

When an aromatic polyamide fiber other than the para type is blended, a fluororesin containing a predetermined amount of tetrafluoroethylene resin is added to form a soft sliding mating material as in the above composition. It is not damaged and has excellent wear resistance.

[0024]

Examples As the PPS resin used in the present invention, synthetic resins composed of various repeating units represented by the following general formula 5 can be mentioned.

[0025]

[Chemical 5]

A particularly typical PPS resin is represented by the formula: ## STR6 ## which is commercially available from Phillips Petroleum, Inc., USA under the trademark "Ryton", and the method for its production is described in US Pat. No. 3,354,129. (Corresponding to Japanese Patent Publication No. 45-3368), the following is disclosed.

Ryton is produced by reacting p-dichlorobenzene with sodium disulfide in an N-methylpyrrolidone solvent at 160 to 250 ° C. under pressure. In this case, it is possible to freely produce resins having various degrees of polymerization ranging from those having no cross-linking to those having partial cross-linking in the resin through the post-heat treatment step. It is possible to arbitrarily select and use those having viscosity characteristics.

[0028]

[Chemical 6]

A linear PPS resin other than Ryton, which does not have a crosslinked structure, may be used.

Next, the fluororesin used in the present invention may be a polymer having a carbon chain having a fluorine atom bonded to the main chain, or a copolymer containing such a polymer. It can be adopted without limitation. That is, as the fluororesin, polytetrafluoroethylene (hereinafter abbreviated as PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (abbreviated as PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) For short),
Ethylene-tetrafluoroethylene copolymer (ETFE
Abbreviated), tetrafluoroethylene-fluoroalkyl vinyl ether-fluoroolefin copolymer (abbreviated as EPE), polytrichlorofluoroethylene, and polyvinylidene fluoride (abbreviated as PVDF). These may be used alone or as a mixture.

When PTFE is used among these fluororesins, even if this is a molding powder,
Fine powders for so-called solid lubricants may be used, but both are usually used together to obtain favorable results. In addition, PTFE (Hostaflore TF9205 manufactured by Hoechst Co., Ltd.), which is a specific commercial product described later, can be used alone to obtain preferable results.

Other commercially available PTFE products include Teflon 7J and TLP manufactured by Mitsui DuPont Fluorochemicals.
-10, Asahi Glass Co., Ltd .: Fluon G163, Daikin Industries Co., Ltd .: Polyflon M15, Lubron L5, and the like. Further, it may be PTFE modified with alkyl vinyl ether.

Examples of PFA include Teflon PFA-J and MP-10 manufactured by Mitsui DuPont Fluorochemicals, Hostafuron TFA manufactured by Hoechst, and Neoflon PFA manufactured by Daikin Industries.

As the FEP, Teflon FEP-J manufactured by Mitsui DuPont Fluorochemicals, manufactured by Daikin Industries, Ltd .:
NEOFLON NC can be mentioned.

As ETFE, Mitsui DuPont Fluorochemical Co .: Tefzel, Asahi Glass Co., Ltd .: Aflon CO
P is mentioned.

Examples of EPE include Teflon EPE-J manufactured by Mitsui DuPont Fluorochemicals.

As PVDF, Kureha Chemical Industry Co .; K
Examples include F polymer and HYLAR manufactured by Ausimont.

Next, the aromatic polyester resin used in the present invention may be not only the polyoxybenzoyl polyester shown in Chemical formula 4 above but also a copolymer containing this as a copolymerization component.

A method for producing such an aromatic polyester resin is described in JP-B-46-6796 and JP-B-47-4.
7870, JP-A-54-46287, and JP-A-54-46291 are well known, and as a commercial product of the polyoxybenzoyl polyester shown in Chemical formula 4, Sumitomo Chemical Co., Ltd. Made: Econole E1
01 etc. can be illustrated.

The para-aromatic polyamide fiber used in the present invention is composed of a polymer containing the repeating unit shown in Chemical formula 3 above, and has a different molecular structure from the meta-aromatic polyamide resin shown in Chemical formula 7 below. Is. Examples of commercially available para-aromatic polyamide fibers include DuPont Toray Kevlar: Kevlar, Nippon Aramid: Twaron, Teijin: Technora.

[0041]

[Chemical 7]

When an aromatic polyamide fiber other than para type (that is, meta type aromatic polyamide fiber) is used, PTFE is used as the fluororesin and a predetermined amount thereof is added. In this case, other fluororesins can be used together. Examples of commercially available meta-aromatic polyamide fibers include DuPont Toray Kevlar: Nomex and Teijin: Conex.

The morphology of such aromatic polyamide fibers has a fiber length of 0.15 to 3 mm and an aspect ratio of 10 to 23.
0 is adopted and the preferable result is obtained. If the fiber length of the aromatic polyamide fiber is less than the predetermined range, the abrasion resistance becomes insufficient, and if the fiber length exceeds the above range, the dispersion in the composition is unsatisfactory, which is not preferable. On the other hand, if the aspect ratio is less than the above range, the shape of the powder is close to that of the powder, and the effect of improving wear resistance becomes insufficient, and if the aspect ratio exceeds the above range, uniform dispersion in the composition is difficult, which is not preferable.

In the present invention, the amount of fluororesin is 5 to.
The reason why the content is limited to 40% by volume is that if it is less than 5% by volume, the lubricating properties are poor, and if it exceeds 40% by volume, the formability is remarkably impaired. From such a tendency, a more preferable compounding ratio is 10%. ~ 35% by volume.

The reason why the amount of PTFE is limited to 18 to 38% by volume is that if it is less than 18% by volume, the composition containing the meta-aromatic polyamide fiber has insufficient lubrication characteristics or the sliding mating material. Depending on the
This is because if it exceeds 38% by volume, the moldability is remarkably impaired. From such a tendency, a more preferable compounding ratio is 20 to 35% by volume.

In the present invention, the reason why the amount of the aromatic polyester resin is limited to 3 to 25% by volume is that the lubricating property is poor if the amount is less than 3% by volume, and if it exceeds 25% by volume, the melt viscosity becomes high and the moldability becomes high. Is unfavorable because it deteriorates or the mechanical strength is lowered, and in view of such a tendency, a more preferable blending ratio is 3 to 20% by volume.

The reason why the blending ratio of the aromatic polyamide fiber used in the present invention is limited to 2 to 20% by volume is that lubricity is poor at less than 2% by volume and abrasion resistance is degraded at more than 20% by volume. Is.

Here, the method of adding and mixing various additives to the PPS resin is not particularly limited, and as generally used, various raw materials containing a resin as a main component are individually separated. Or in a batch, and dry mixed by a mixer such as a Henschel mixer, a ball mill, a tumbler mixer, and then supplied to an injection molding machine or a melt extrusion molding machine with good melt mixing properties, or in advance,
A method of melt mixing with a hot roll, kneader, Banbury mixer, melt extruder, or the like may be adopted.

Further, when the composition of the present invention is molded, a usual method such as compression molding, extrusion molding, injection molding or the like is used, or after the composition is melt-mixed, the composition is jet-milled, freeze-milled or the like. It is also possible to carry out fluidized dip coating, electrostatic powder coating or the like using the obtained powder without crushing and classifying to a desired particle size, or without classifying. It is also possible to disperse the obtained powder in a solvent and perform spray coating or dip coating.

In the present invention, various additives may be added to the lubricating composition containing PPS resin as a main component. For example, a wear resistance improver is incorporated to further improve the lubricity of the composition.

Specific examples of the wear resistance improver include carbon, graphite, mica, talc, wollastonite, metal oxide powder, whisker such as calcium sulfate, molybdenum disulfide, phosphate, carbonate and stearin. Examples thereof include acid salts, molten fluororesins, and ultrahigh molecular weight polyethylene.

The heat-resistant plain bearing of the present invention molded from the above-mentioned materials is not limited in its shape, and may have a shape adapted to the shape of the heating / pressurizing roller, peripheral devices and housing. For example, as shown in FIG. 1, the bearing may be formed of not only a single material but also a two-color molding method to form a composite material including the bearing portion 1 and the fixing metal portion 2.

As shown in FIG. 2, the heat-resistant plain bearing of the present invention comprises the bearing portion 3 and a heat-resistant and heat-insulating resin such as PPS, polyamide-imide (PAI) or polyimide (PI), or A two-color molded bearing composed of a resin portion 4 in which an inorganic filler or an organic filler is added may be used. Such a bearing has a 100% dimensional stability in order to ensure dimensional stability during high temperature use, excluding strain during molding.
It is desirable to perform annealing heat treatment at about 250 ° C. for about 0.5 to 24 hours.

The raw materials used in Examples and Comparative Examples of the present invention are collectively shown as follows. The mixing ratio of each component is% by volume.

(1) PPS resin (manufactured by Tososa Steel Co., Ltd .: PPS # 160), (2) PPS resin (KPS-W20 manufactured by Kureha Chemical Co., Ltd.)
5), (3) Tetrafluoroethylene resin (Mitsui DuPont Fluorochemical Co .: Teflon 7J, for molding) (4) Tetrafluoroethylene resin (Kitamura Co .: KTL6)
10, for lubrication) (5) Tetrafluoroethylene resin (Hoechst: Hostaflore TF9205, for lubrication) (6) ETFE (Asahi Glass: Aflon COP Z-8)
820) (7) Tetrafluoroethylene-hexafluoropropylene copolymer [FEP] (manufactured by Daikin Industries, Ltd .: NEOFLON NC-1500) (8) Polyvinylidene fluoride [PVDF] (manufactured by Ausimont: HYLAR 301F) (9) Fragrance Group polyester resin (Sumitomo Chemical Co., Ltd .: Econoll E101S2) (10) Para aromatic polyamide fiber (DuPont Toray Kevlar: Kevlar 49 cut fiber fiber length 1 mm) (11) Para aromatic polyamide fiber (Japan Aramid: Twaron 1010 cut fiber, fiber length 0.2
5 mm) (12) Meta-type aromatic polyamide fiber (made by Teijin: Conex cut fiber 2 de, fiber length 1 mm) (13) Carbon black (made by Lion: Ketjen EC-X), (14) Graphite (made by Lonza) : KS-6) (15) Ultra high molecular weight polyethylene (Mitsui Petrochemical Industrial Co., Ltd .: Miperon XM-220).

[Examples 1 to 13] Raw materials were thoroughly mixed with a Henschel mixer in the proportions shown in Table 1 and fed to a twin-screw melt extruder, and the cylinder temperature was 300 ° C and the rotation speed was 10
Extruded and granulated under melt-mixing conditions of 0 rpm, the pellets obtained were resin temperature 310 ° C., injection pressure 800 kgf / c
m ^2, the outer diameter by injection molding under the conditions of a mold temperature of 140 ° C. 28 m
A ring-shaped test piece having a diameter of m, an inner diameter of 20 mm and a width of 5 mm was formed. Using this test piece, the following high temperature radial friction and wear test was conducted.

[High Temperature Radial Friction and Wear Test] A rotating shaft made of aluminum alloy A5056 or A6063 (both having a surface roughness of 3.2S) was used as a mating member, and a ring-shaped test piece was fitted on the outer periphery of the mating member, and this was mated. It is pressed against the peripheral surface of the material with a pressure of 3.5 kgf / cm ² , the surface temperature of the rotary shaft is controlled to 200 ° C., and a torque meter is attached to this, and the peripheral speed is 2.8 m / min for 50 hours. It was rotated continuously. After this, the wear coefficient as the wear amount of the test piece x 1
0 ^-10 cm ³ / (kgf · m) and torque of rotating shaft (k
gf · cm) was measured and the degree of damage to the mating material was observed. The degree of damage was expressed by a three-stage evaluation of no damage (○ mark), slightly damage (Δ mark) or damage (× mark), and the results are summarized in Table 3.

[0058]

[Table 1]

[0059]

[Table 2]

[0060]

[Table 3]

Comparative Examples 1 to 5 Test pieces were prepared in the same manner as in Example 1 except that the raw materials were mixed in the proportions shown in Table 2, and the high temperature radial friction and wear test was conducted.
Table 3
It was shown to.

As is clear from the results shown in Table 3, Comparative Examples 1 to 5 have a large amount of wear and rotational torque, and Comparative Examples 2, 4 and 5 have a large damage to the mating material, and all are preferable. It was not a physical property. Further, in Comparative Example 4, the wear was extremely large, and the test was stopped after 4 hours.

In Comparative Example 2, since the aromatic polyamide fiber was not of the para type and the amount of PTFE added was less than the predetermined amount, both abrasion resistance and damage to the mating material were poor.

On the other hand, in Examples 1 to 13, both the wear amount and the rotation torque were low, and the aluminum alloy (A5056) as the mating material was not damaged.

Here, in the friction and wear test, judgment was made on the basis of the case where the Mg-containing aluminum alloy (A5056) was used as the sliding partner material, but in Examples 4 to 8 and 10 to 13, Mg and Si were determined. Even when an aluminum alloy (A6063) containing A5056, which is harder than A5056, was used as the sliding mating material, good results were obtained with respect to the amount of wear of itself, the rotating torque, and the damage to the mating material.

Example 2 shows good results when A5056 is used as the sliding mating material, and it can be used as a sliding material, but this one has a PTFE content less than the predetermined amount. , A6063 was used as the sliding mating material, the amount of self-wear increased and the rotation torque was also high.

In Example 4, since the content of PTFE was within the predetermined range, even when A6063 was used as the sliding mating material, the wear amount of self was small and the rotation torque was low as in the case of the A5056 mating material. Moreover, there was no damage to the mating material, and it was a particularly excellent sliding material.

In Example 12, one kind of predetermined PTFE manufactured by Hoechst Co. was blended as the fluororesin, and
The composition adopts FEP, and almost the best results were obtained in almost all the test items using the above-mentioned two kinds of aluminum alloys as the sliding mating materials.

Further, in Examples 2 to 5, 7 and 9 in which ETFE was used as the fluororesin, particularly excellent results were obtained in that the amount of self abrasion was small.

The volume resistance of Example 8 was measured and found to be 2.4 × 10 ² Ωcm, indicating semiconductivity.

[0071]

[Effect] As described above, the heat-resistant / lubricating resin composition of the present invention comprises a polyphenylene sulfide resin as a main component and a fluororesin, an aromatic polyester resin, and a para-aromatic polyamide fiber in a predetermined amount. Since it is a composition, it has excellent low friction characteristics and wear resistance in addition to injection moldability, and is not suitable when a soft alloy such as an aluminum alloy containing Mg is used as a sliding partner material. It has the advantage of being aggressive.

A composition employing an aromatic polyamide fiber other than the para-based one has the same low friction as the above composition when the one containing a predetermined amount of tetrafluoroethylene resin is used as the above-mentioned fluororesin. It is a composition that exhibits properties and wear resistance and that is unlikely to damage the soft alloy with which it slides. This composition is suitable not only for aluminum alloys containing Mg, but also for Mg
Even when an aluminum alloy containing Si and Si is used as a sliding partner, there is an advantage of having the above-mentioned good wear resistance and damage resistance.

Further, since these resin compositions have all the characteristics such as heat resistance, low friction characteristics, abrasion resistance and non-aggressiveness, they are highly effective in fixing devices such as copying machines and laser beam printers. There is also an advantage that it can be applied as a heat resistant sliding bearing with high performance.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment.

FIG. 2 is a perspective view showing another embodiment.

FIG. 3 is a cross-sectional view illustrating a usage state of a bearing in a heating / fixing device.

FIG. 4 is a cross-sectional view illustrating a usage state of a bearing in another heating / fixing device.

[Explanation of symbols]

 1, 3 Bearing part 2 Fixing metal part 4 Resin part 10 Heating roller 11 Pressure roller 12 Heater 13 and 14 Radial bearing made of synthetic resin 15 Fixing film 16 Ceramic heater

Claims (7)

[Claims] 1. A polyphenylene sulfide resin as a main component, 5 to 40% by volume of a fluororesin, 3 to 25% by volume of an aromatic polyester resin, and 2 to 20% by volume of a para aromatic polyamide fiber are added as essential components. A heat resistant / lubricating resin composition. 2. The heat-resistant and lubricating resin composition according to claim 1, wherein the para-aromatic polyamide fiber is a para-aromatic polyamide fiber containing a repeating unit represented by the following chemical formula 1. Embedded image 3. The heat resistant / lubricating resin composition according to claim 1, wherein the fluororesin is an ethylene-tetrafluoroethylene copolymer or a tetrafluoroethylene-hexafluoropropylene copolymer. 4. The fluororesin is a mixture of polytetrafluoroethylene and a tetrafluoroethylene-hexafluoropropylene copolymer.
The heat-resistant / lubricating resin composition described. 5. Polyphenylene sulfide resin as a main component, tetrafluoroethylene resin 18-38% by volume
And 3 to 25% by volume of aromatic polyester resin and 2 to 20% by volume of aromatic polyamide fiber as an essential component. 6. The aromatic polyester resin has the following chemical formula 2.
A resin containing a repeating unit represented by the formula:
The heat resistant / lubricating resin composition according to any one of 5 above. Embedded image 7. A heat-resistant plain bearing formed by molding the heat-resistant / lubricating resin composition according to claim 1. Description: