EP0069577A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Process for the production of string-like porous material
Assignee: Sumitomo Electric Industries Ltd
•
Filing: 1982-07-05
•
Granted: —
•
Expires: 2002-07-05
Abstract
Abstract A process for producing a tube or rod of a polytetrafluoroethylene is described. The process comprises molding a polytetrafluoroethylene containing a liquid lubricant into a tube or rod by a paste process, removing the liquid lubricant, stretching the tube or rod in the lengthwise direction, and thereafter, by sintering the stretched tube or rod at a temperature of at least 327°C wherein the stretching of the tube or rod is carried out by the use of at least one pair of heating rolls which are each provided with a plurality of grooves. The process provide uniform stretching making it possible to produce a tube or rod with very small internal diameter.
Inventors
- 👤 Okita Koichi
- 👤 Asako Shigeru
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 07:06
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/02; D01F6/08; D01F6/12; B; B29; B29C; B29C67/00; B29C67/20; B29C67/205; D01D; D01D5/00; D01D5/12; D01D5/16; D01D5/24
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
91 words
A process for producing a string-like porous material of a polytetrafluoroethylene, comprising the steps of: molding a polytetrafluoroethylene into a string-like shape, the polytetrafluoroethylene containing a liquid lubricant, the molding being performed by a paste process; removing the liquid lubricant; stretching the string-like material in the lengthwise direction; and sintering the stretched string-like material at a temperature of 327°C or more, wherein the stretching is performed in the lengthwise direction by means of a pair of heating rolls wherein the heating rolls are each provided . with a plurality of grooves.
Claim 2
Dependent Claim
91 words
A process for producing a string-like porous material of a polytetrafluoroethylene, comprising the steps of: molding a polytetrafluoroethylene into a string-like shape, the polytetrafluoroethylene containing a liquid lubricant, the molding being performed by a paste process; removing the liquid lubricant; stretching the string-like material in the lengthwise direction; and sintering the stretched string-like material at a temperature of 327°C or more, wherein the stretching is performed in the lengthwise direction by means of a pair of heating rolls wherein the heating rolls are each provided . with a plurality of grooves.
Claim 3
Dependent Claim
58 words
A process for producing a string-like porous material of a polytetrafluoroethylene, as claimed in Claim 1, wherein the stretching is carried out utilizing a first pair of heating rolls and a second pair of heating rolls, wherein said first pair of heating rolls are rotated at a different speed of rotation than said second pair of heating roll.
Claim 4
Dependent Claim
75 words
A process for producing a string-like porous material of a polytetrafluoroethylene, as claimed in any of Claims 1 or 2, wherein the molded string-like shape is placed on a pair of heating rolls in a Figure 8 configuration and further wherein the pair of heating rolls are rotated at the same speed in order to create a uniform compression force during the stretching, the force being applied in the peripheral direction of the string-like material.
Claim 5
Dependent Claim
81 words
A process for producing a string-like porous material of a polytetrafluoroethylene, as claimed in Claim 2, wherein the first pair of heating rolls are rotated at the same speed and maintained at the same temperature, and further wherein the second pair of heating rolls are rotated at a speed different from said first pair of heating rolls, and wherein the first pair of heating rolls are maintained at a temperature at least 50°C different from the second pair of heating rolls.
Claim 6
Dependent Claim
61 words
A process for producing a string-like porous material of a polytetrafluoroethylene, as claimed in Claim 2, wherein the temperature of the first pair of heating rolls is maintained at a temperature of from 250°C up to the melting point of the polytetrafluoroethylene, and the temperature of the second pair of heating rolls is maintained at atem- perature of 260°C or less.
Claim 7
Dependent Claim
36 words
A process for producing a string-like porous material of a polytetrafluoroethylene, as claimed in Claim 5, wherein the first pair of heating rolls are rotated at a speed slower than the second pair of heating rolls.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.