Patent EP0051957A2 successfully refreshed from Google Patents.
EP0051957A2
Expired / Lapsed
EP
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Porous PTFE articles and a process for their manufacture
Assignee: W.L. Gore and Associates Inc
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Filing: 1981-10-27
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Granted: —
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Expires: 2001-10-27
Abstract
Abstract A method for producing a multi-component. porous PTFE article comprises the steps of bringing components of PTFE containing a liquid lubricant into intimate contact with each other, removing the lubricant and stretching the composite article in one or more directions. The PTFE components may optionally contain a filler. The resultant product has a virtually uninterrupted structure at the bond between its components and possesses very high bond strengths.
Inventors
- 👤 Daniel E. Hubis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 22:23
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/32; B32B27/322; A; A61; A61L; A61L27/00; A61L27/14; A61L27/16; A61L27/50; A61L27/56; B29; B29C; B29C55/00; B29C55/02; B29C55/023; B32B38/00; B32B38/0012; B32B5/00; B32B5/18; C; C08; C08J; C08J5/00; C08J5/12; C08J5/121; C08J9/00; C08J9/28; B29K; B29K2027/00; B29K2027/12; B29K2027/18; B32B2038/0028; B32B2266/00; B32B2266/02; B32B2266/0214; B32B2266/025; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/52; B32B2327/00; B32B2327/12; B32B2327/18; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18; Y; Y10; Y10S; Y10S277/00; Y10S277/935; Y10S277/944; Y10S277/945; Y10S277/946; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249981; Y10T428/249986; Y10T428/25; Y10T428/251; Y10T428/252; Y10T428/26; Y10T428/269; Y10T428/29; Y10T428/2913; Y10T428/2918; Y10T428/30; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T428/31652; Y10T428/31663
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
76 words
A porous polytetrafluoroethylene article characterised in that it comprises at least two components of polytetrafluoroethylene bonded together at the interface between the, or each two, adjacent said components, the porosity of each component at the interface being the same as the porosity within said component, and the bond strength in the Z direction (i.e. direction perpendicular to the interface) being not less than the strength in the Z direction of the weaker of said two components.
Claim 2
Dependent Claim
76 words
A porous polytetrafluoroethylene article characterised in that it comprises at least two components of polytetrafluoroethylene bonded together at the interface between the, or each two, adjacent said components, the porosity of each component at the interface being the same as the porosity within said component, and the bond strength in the Z direction (i.e. direction perpendicular to the interface) being not less than the strength in the Z direction of the weaker of said two components.
Claim 3
Dependent Claim
61 words
An article according to claim 1 characterised in that the porosity of the components has been increased subsequent to bonding together of the components, the bonding of the components having taken place in the presence of a lubricant which has subsequently been removed, the removal of the lubricant having taken place prior to said increase in the porosity of the components.
Claim 4
Dependent Claim
47 words
An article according to claim 1 or claim 2 characterised in that the microstructure of said article consists of nodes interconnected by fibrils said microstructure transcending said interface, and the article having a thickness exceeding 0.0005 inch, in particular exceeding 0.040 inch, more particularly exceeding 0.075 inch.
Claim 5
Dependent Claim
65 words
An article according to any preceding claim characterised in that it contains a filler in an amount between 4.5% and 50% by weight, the filler being any one or more of the following namely titanium dioxide, preferably having a mean diameter of about 20 nonometers, carbon black, graphite, zirconium dioxide, asbestos, silica, mica, glass, potassium titinate, polysiloxane or other, a dielectric fluid, and a pigment.
Claim 6
Dependent Claim
34 words
An article according to any one of claims 1 to 4 characterised in that it has been heated above the crystalline melt point of polytetrafluoroethylene for a time sufficient to partially sinter said article.
Claim 7
Dependent Claim
81 words
A process for making a multi-component porous article of expanded polytetrafluoroethylene characterised by the steps of: (a) intimately contacting at least two components of polytetrafluoroethylene containing a liquid lubricant at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) removing lubricant from said multi-component article; (c) expanding in at least one direction said multi-component article, from which the lubricant has been removed, at a rate exceeding 10% per second at an elevated temperature below the crystalline melt point of polytetrafluoroethylene.
Claim 8
Dependent Claim
81 words
A process for making a multi-component porous article of expanded polytetrafluoroethylene characterised by the steps of: (a) intimately contacting at least two components of polytetrafluoroethylene containing a liquid lubricant at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) removing lubricant from said multi-component article; (c) expanding in at least one direction said multi-component article, from which the lubricant has been removed, at a rate exceeding 10% per second at an elevated temperature below the crystalline melt point of polytetrafluoroethylene.
Claim 9
Dependent Claim
45 words
A process according to claim 6 characterised in that said contacting is performed in the nip between two calender rolls, and that said expansion is performed at a rate exceeding 50% per second, in particular exceeding 1000% per second, more particularly exceeding 10,000% per second.
Claim 10
Dependent Claim
23 words
A process according to claim 6 characterised in that said components are expanded porous polytetrafluoroethylene components that have been wetted with liquid lubricant.
Claim 11
Dependent Claim
74 words
A process for making a multi-component porous article of expanded polytetrafluoroethylene comprising: (a) initially contacting at least two components of polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) stretching said multi-component article with lubricant present at a temperature below the boiling point of said lubricant; (c) removing the lubricant from said stretched multi-component article; (d) expanding said multi-component article at a rate exceeding 10% per second.
Claim 12
Dependent Claim
74 words
A process for making a multi-component porous article of expanded polytetrafluoroethylene comprising: (a) initially contacting at least two components of polytetrafluoroethylene containing a liquid lubricant, at a temperature below the crystalline melt point of polytetrafluoroethylene; (b) stretching said multi-component article with lubricant present at a temperature below the boiling point of said lubricant; (c) removing the lubricant from said stretched multi-component article; (d) expanding said multi-component article at a rate exceeding 10% per second.
Claim 13
Dependent Claim
66 words
A multi-component porous article comprising at least two components of polytetrafluoroethylene characterised in that they have been bonded together at the interface between t'he or each two adjacent said components by intimately contacting the said two components in the presence of a liquid lubricant and thereafter expanding the article to increase the porosity thereof, the porosity and the strength of the article being substantially uniform throughout.
Claim 14
Dependent Claim
66 words
A multi-component porous article comprising at least two components of polytetrafluoroethylene characterised in that they have been bonded together at the interface between t'he or each two adjacent said components by intimately contacting the said two components in the presence of a liquid lubricant and thereafter expanding the article to increase the porosity thereof, the porosity and the strength of the article being substantially uniform throughout.
References Cited (Backward Citations)
No citation records indexed.
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