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...
Reexamination Certificate
2002-04-19
2004-07-06
Short, Patricia A. (Department: 1712)
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...
C524S508000, C525S151000, C525S190000, C525S934000
Reexamination Certificate
active
06759470
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a polytetrafluoroethylene (PTFE) resin powder for molding which contains a heat resistant aromatic polyoxybenzoyl ester resin powder, undergoes less separation of the heat resistant resin powder and has a high apparent density and a high powder flowability. A molded article produced from such a resin powder has a high elongation which has not been obtained so far and is suitable for not only a sealing material such as a packing and gasket but also a sliding material such as a lubrication-free bearing, diaphragm, bellows, tube, hose, casing, lining material, back-up ring, bearing, etc.
The heat resistant aromatic polyoxybenzoyl ester resin powder is known as an organic filler for a PTFE molding powder and is excellent in that the attack by it upon an opposite material is less than that by an inorganic filler. However there is a problem that a phenomenon of separation of a filler arises, that is, the filler is separated from a granulate when the filler is granulated with the PTFE molding powder in water and thereby a final molded article is inferior in a dispersibility of the filler. As a result, an elongation of the obtained molded article is small and therefore in case of the use as an O-ring, etc., fitting work thereof becomes difficult.
An object of the present invention is to provide a resin powder for molding which undergoes less separation of the filler irrespective of the heat resistant aromatic polyoxybenzoyl ester resin powder being contained therein as the filler, has a high apparent density and a high powder flowability and gives a molded article having a high elongation, and also to provide a preparation process of the resin powder.
SUMMARY OF THE INVENTION
Namely, the present invention relates to a resin powder for molding which comprises (A) 35 to 98% by weight of a PTFE powder having an average particle size of not more than 120 &mgr;m, (B) 35 to 2% by weight of a heat resistant aromatic polyoxybenzoyl ester resin powder subjected to water repelling treatment and (C) 30 to 0% by weight of an inorganic filler as an optional component, has an apparent density of not less than 0.6 g/cm
3
and an average particle size of not more than 800 &mgr;m, and provides a molded article having an elongation at break of not less than 20%.
When the resin powder for molding comprises two components of the PTFE powder (A) and the specific water-repelling-treated heat resistant resin powder (B), it is preferable that an amount of the PTFE powder (A) is from 65 to 98% by weight and an amount of the specific water-repelling-treated heat resistant resin powder (B) is from 35 to 2% by weight. Further when the inorganic filler (C) is added thereto, it is preferable that an amount of the powder (A) is from 35 to 97% by weight, an amount of the specific water-repelling-treated heat resistant resin powder (B) is from 35 to 2% by weight and an amount of the inorganic filler (C) is from 30 to 1% by weight.
REFERENCES:
patent: 5709944 (1998-01-01), Kokumai
patent: 6451903 (2002-09-01), Asano
patent: 1-259055 (1989-10-01), None
patent: 5-287151 (1993-11-01), None
patent: 7-228744 (1995-08-01), None
patent: 9-157472 (1997-06-01), None
patent: 10-251413 (1998-09-01), None
International Preliminary Examination Report for PCT/JP00/07221 dated Oct. 23, 2001.
Asano Michio
Sukegawa Masamichi
Daikin Industries Ltd.
Short Patricia A.
LandOfFree
Resin powder for molding and preparation process of same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Resin powder for molding and preparation process of same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Resin powder for molding and preparation process of same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3217459