Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1984-10-17
1986-08-12
Lieberman, Allan M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
428327, 428458, 428461, 428463, 524428, 524430, 524443, 524493, 524496, 524520, 525199, C08K 304, C08K 314, C08K 320, C08L 2718
Patent
active
046056955
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a heat- and abrasion-resistant coating material used for protecting a sliding member without lubrication oil.
BACKGROUND ART
Oil free type vane pumps are used as a supercharger for an automobile engine and as a refrigerating compressor for a vehicle and provided with sliding members made of self-lubricating materials or covered by a self-lubricating resin. However, the known self-lubricating resins are unsatisfactory in durability under severe operating conditions. There is a strong demand for an improved resin coating material.
To meet the demand as described above, it is an object of the present invention to provide a resin material that is superior in heat- and abrasion-resistant properties under severe operating conditions.
DISCLOSURE OF THE INVENTION
The material according to the present invention is characterised in that a powder mixture prepared by mixing a finely powdered resin mixture composed of 70 to 90 weight % of finely powdered tetrafluoroethylenehexafluoropropylene copolymer resin and 10 to 30 weight % of finely powdered polyimide resin with 5 to 15 weight %, based on the total weight, of one or more of zirconia (ZrO.sub.2), silicon carbide (SiC), silicon nitride (Si.sub.3 N.sub.4), alumina (Al.sub.2 O.sub.3), carbon (C) and tetrafluoroethylene resin of 0.2 to 1.0 micron meter in particle size is applied, as a suspension, onto a sliding member, and baked to form a coating thereon. Usual aqueous and organic solvents, such as toluene and methanol, are available in making the suspension, which is coated on the surface of the sliding member by means of coating, such as spraying and the like, and then baked to a film at a range of 300.degree. to 390.degree. C. for about 15 minutes.
The activity of the individual components and the reason for limiting their amounts are explained below.
The finely powdered tetrafluoroethylenehexafluoropropylene copolymer resin is the base of the inventive material and necessary for improvements in both heat and abrasion resistance and in adhesion. The amount of the copolymer resin is closely related to that of the polyimide resin. If it is less than 70 weight %, the coated material is unsatisfactory in adhesion and abrasion resistance, thereby having the possibility of peeling. On the other hand, if it is more than 90 weight %, the copolymer resin makes a poor combination with other components. Therefore, the amount is restricted to a range of 70 to 90 weight %.
The finely powdered polyimide resin is added as a binder. If it has an amount less than 10 weight %, it is insufficient to bind the mixture and keep the same adhesive. On the other hand, if it is more than 30 weight %, the baked material has an abrasion resistant lowered due to lack of the tetrafluoroethylenhexafluoropropylene copolymer resin. Therefore, it is limited to a range of 10 to 30 weight %.
One or more of powdered ZrO.sub.2, SiC, Si.sub.3 N.sub.4, Al.sub.2 O.sub.3, C, and tetrafluoroethylene resin are mixed in a rate of 5 to 15 weight % based on the mixture of the tetrafluorohexafluoropropylene resin and polyimide resin. If the amount is less than 5 weight %, the abrasion resistance is unsatisfactory. On the other hand, the amount is more than 15 weight %, the powders are unevenly distributed and easy to drop out of the mixture and give damage to the opposite sliding member. Therefore, the ratio is limited to a range of 5 to 15 weight %. Their particle size is restricted within a range of 0.2 to 1.0 micron meter. The reason for this is that it is inferior in abrasion resistance if smaller than 0.2 micron meter and likely to cause abnormal wear on the opposite sliding member if larger than 1.0 micron meter.
The material has a composition of the base of tetrafluorohexafluoropropylene copolymer resin and additives of polyimide resin and one or more of ZrO.sub.2, SiC, Si.sub.3 N.sub.4, Al.sub.2 O.sub.3, C, and tetrafluoroethylen resin. The base is superior in heat and abrasion resistance. The polyimide resin gives the material a good adhesive pro
REFERENCES:
patent: 2789960 (1957-04-01), Smith
patent: 2976257 (1961-03-01), Dawe et al.
patent: 3531432 (1970-09-01), Graver
patent: 3769252 (1973-10-01), Fuji et al.
patent: 3904575 (1975-09-01), Satokawa et al.
Horikoshi Yukio
Sakamaki Hiroshi
Yanagihashi Kikuji
Lieberman Allan M.
Nippon Piston Ring Co. Ltd.
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