Sealing element and/or guide ring made of a composition of polytetrafluoroethylene, perfluoroalkoxy polymer, and filler
AssigneeBurckhardt Compression AG
InventorBernhard Dominik THURNHERR
Life of this patent
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Abstract
The present invention relates to a sealing element and/or guide ring manufactured from a composition comprising: i) 50% to 98% by weight of polytetrafluoroethylene and/or modified PTFE, ii) 1% to 49% by weight of perfluoroalkoxy polymer and iii) 1% to 49% by weight of an inorganic filler selected from the group comprising charcoal, graphite, glass fibers, carbon fibers, molybdenum disulfide, metals such as copper, alloys such as bronze, ceramic particles such as aluminum oxide and any desired mixtures of two or more of the aforementioned substances.
Claims14
A sealing element and/or guide ring manufactured from a composition comprising:
- i) 50% to 98% by weight of polytetrafluoroethylene and/or modified polytetrafluoroethylene,
- ii) 1% to 49% by weight of perfluoroalkoxy polymer and
- iii) 1% to 49% by weight of an inorganic filler selected from the group consisting of charcoal, graphite, glass fibers, carbon fibers, molybdenum disulfide, metals, alloys, ceramic particles and any mixtures of two or more of the aforementioned substances,
- wherein the chemically modified polytetrafluoroethylene optionally present is a polymer composed of tetrafluoroethylene monomer and less than 1% by weight of comonomer, and
- wherein the perfluoroalkoxy polymer is a copolymer of tetrafluoroethylene and perfluoroalkoxy comonomer containing more than 1% by weight of perfluoroalkoxy comonomer.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- the polytetrafluoroethylene and/or chemically modified polytetrafluoroethylene i) has a number-average molecular weight of 106 g/mol or greater.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- the polytetrafluoroethylene and/or chemically modified polytetrafluoroethylene i) has an average particle size measured according to DIN ISO 13320 of 20 to 650 μm and preferably of 20 to 50 μm.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- the perfluoroalkoxy polymer ii) has the following general formula:
- in which R is a C1-4-perfluoroalkyl radical and preferably a C1-3-perfluoroalkyl radical and m and n represent the number of repeating units, where n and m are preferably independently a number from 1 to 10000.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- the perfluoroalkoxy polymer ii) has a melt flow index measured according to DIN EN ISO1133 with 5 kg at 372° of 1 to 30 g/10 min and preferably a melt flow index of 2 to 20 g/10 min.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- the perfluoroalkoxy polymer ii) has an average particle size measured according to DIN ISO 13320 of 20 to 650 μm and preferably of 20 to 50 μm.
The sealing element and/or guide ring, wherein the composition comprises:
- i) 50% to 98% by weight of polytetrafluoroethylene and/or modified polytetrafluoroethylene,
- ii) 1% to 49% by weight of a thermoplastic perfluoropolymer other than polytetrafluoroethylene and
- iii) 1% to 49% by weight of an inorganic filler selected from the group consisting of charcoal, graphite, glass fibers, carbon fibers, molybdenum disulfide, metals such as copper, alloys such as bronze, ceramic particles such as aluminum oxide and any desired mixtures of two or more of the aforementioned substances.
The sealing element and/or guide ring as claimed in at least one of the preceding claims,
- characterized in that
- it is a piston ring or a packing ring.
Dependencies are inferred from the claim text.