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US 10,093,069 B2Granted
Method of forming large diameter thermoplastic seal
AssigneeSaint-Gobain Performance Plastics Corporation
InventorsYuxiang Liu, Rojendra Singh
Life of this patent
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Abstract
A structure for and method of producing large diameter seal rings. Preferred embodiments of the present invention make use of a co-extruded “support” layer of a polymer showing better weld quality and strength. The use of a co-extruded support polymer bonded to the functional polymer can be used to improve the strength of the entire weld, including the weld of functional polymer layer.
Claims18
A method of forming a seal ring, the method comprising:
- forming a thermoplastic rod from at least a longitudinal layer of a first polymer and a longitudinal layer of a second polymer, and the extruded rod having first and second ends;
- heating the thermoplastic rod to a first temperature above the glass transition temperature of the first and second polymers;
- bending the thermoplastic rod into a circular structure while maintaining the temperature at least at the first temperature;
- heating the first and second ends of the extruded rod to a temperature above the melting temperature of the first and second polymers;
- and
- bringing the heated first and second ends of the extruded rod together to form a weld joining the ends together, wherein the welded second polymer has at least a first mechanical property that is more desirable than the first mechanical property of the welded first polymer, so that that the first mechanical property of the weld joining the ends of the extruded rod together is also more desirable than the first mechanical property of the welded first polymer, wherein the first polymer is oriented exclusively toward the interior of the seal, where the first mechanical property is selected from the group consisting of elongation at break, tensile strength, or tensile modulus.
3 more elements
A method of forming a seal ring, the method comprising:
- forming a thermoplastic rod by coextrusion of a polytetrafluoroethylene (PTFE) filled polymer and an unfilled polymer so that the formed thermoplastic rod includes at least a first layer of PTFE filled polymer and a second layer of unfilled polymer, the thermoplastic rod having first and second ends;
- heating the thermoplastic rod to a temperature above the glass transition temperature of the PTFE filled polymer and the unfilled polymer;
- bending the thermoplastic rod into a circular structure while maintaining the temperature above the glass transition temperature;
- bringing the heated first and second ends of the thermoplastic rod together to form a weld joining the ends together so that the first and second ends of the layer of PTFE filled polymer are joined and the first and second ends of the layer of unfilled polymer are joined, wherein the PTFE filled polymer is oriented exclusively toward the interior of the seal, wherein the weld joining the ends of the thermoplastic rod together has an elongation-to-break of at least 3%.
1 more element
A method of forming a seal ring by polymer welding, the method comprising:
- forming a thermoplastic rod including at least two layers by coextruding a first layer of a PTFE filled polymer and a second layer of a support polymer, the PTFE filled polymer when welded having an elongation-to-break of less than 3%, the support polymer when welded having an elongation-to-break of at least 3%, and the formed thermoplastic rod having first and second ends;
- heating the thermoplastic rod to a temperature above the glass transition temperature of the first and second layers;
- bending the thermoplastic rod into a circular shape;
- heating the first and second ends of the thermoplastic rod to a temperature above the melting temperature of the first and second layers;
- and
- bringing the heated first and second ends of the thermoplastic rod together to form a weld joining the ends together so that the first and second ends of the first layer are joined and the first and second ends of the second layer are joined, the weld having an elongation-to-break of at least 3%, wherein the PTFE filled polymer is oriented exclusively toward the interior of the seal.
3 more elements
Dependencies are inferred from the claim text.