Shaped article of a tetrafluoroethylene polymer
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsMasayuki Sukigara, Yasushi Kaneko, Hiroshi Kataoka
Life of this patent
Estimating the term…
Abstract
A shaped article comprised of a tetrafluoroethylene polymer with a number average molecular weight of at least about 10.sup.6 which exhibits specific heat shrinking properties represented by an average maximum expansion ratio of from 2 to 10, a least maximum shrinkage ratio of 0.71 or less, an orientation release stress at 200.degree. C. of less than 5 Kg/cm.sup.2 and a shrinking starting temperature of at least 80.degree. C. The shaped article has excellent compression creep resistance, compression resistance, impact strength, dimensional stability, gas barrier property and tensile strength. Accordingly, it can be advantageously utilized as a sealant, a lining material, a bearing pad, a sliding pad, etc.
Claims10
A shaped article comprising a tetrafluoroethylene polymer having a number average molecular weight of at least about 10.sup.6, which article has a specific gravity of at least 1.8 and an orientation release stress at 200.degree. C. of less than 5 Kg/cm.sup.2, and which article has a shrinking starting temperature of at least 80.degree. C. as measured by thermomechanical analysis and has heat shrinking properties such that upon heating to a temperature higher than the shrinking starting temperature, shrinking occurs in a plurality of planes contiguously aligned in substantially parallel relationship within the shaped article and simultaneously expansion occurs in a direction perpendicular to said planes, wherein said shaped article exhibits an average maximum expansion ratio of from 2 to 10 as measured in terms of a ratio of a maximum expansion in the direction perpendicular to said planes and a least maximum shrinkage ratio of 0.71 or less as measured in terms of a ratio of a maximum shrinkage in a direction in which the maximum shrinkage is least.
Dependencies are inferred from the claim text.