Finely divided, irradiated tetrafluorethylene polymers
AssigneeImperial Chemical Industries PLC
InventorsMichael Trevenen Brown, William George Rodway
Life of this patent
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Abstract
Dry non-sticky fine lubricant powders are made by .gamma.-irradiation of unsintered coagulated dispersion grade tetrafluoroethylene polymers and organic dispersions are made by dispersing the irradiated polymer in an organic medium.
Claims4
An unsintered powder of a coagulated dispersion grade of a homopolymer of tetrafluoroethylene or a copolymer of tetrafluoroethylene with up to 10% by weight of the copolymer, of an ethylenically unsaturated comonomer, characterised in that the powder has been irradiated by gamma radiation until it has received a dose of from 2 to 50 M Rad, has a particle size of 3 to 5 microns measured optically, a surface area of 3-7 m.sup.2 /gm, and a sheen gauge result measured by the sheen gauge test of at least 1, 2, 5, 20, smear.
An unsinteredpowder of a coagulated dispersion grade of a homopolymer of tetrafluoroethylene or a copolymer of tetrafluoroethylene with up to 10% by weight of the copolymer, of an ethylenically unsaturated comonomer, characterised in that the powder has been irradiated by gamma radition until it has received a dose of from 2 to 50 M Rad, has a median number average particle size of 3 to 4 microns measured optically, a surface area of 3 to 7 m.sup.2 /gm, and a sheen gauge result measured by the sheet gauge test of at least 1, 2, 5, 20, smear.
Dependencies are inferred from the claim text.