Claims
- 1. A method of welding at least two layers of a thermoplastic polyurethane elastomer film, comprising the steps of:
- (a) pre-heating a welding platen to a temperature above a Vicat softening temperature and below a thermoplastic elastomer film deformation temperature of said thermoplastic polyurethane elastomer film, said thermoplastic polyurethane elastomer film having a thickness in a range from about 0.5 to about 5.0 mils (0.0127 to 0.127 mm);
- (b) placing at least two layers of said polyurethane film on the preheated platen, said platen heating said thermoplastic polyurethane elastomer film to a temperature above the Vicat softening temperature of said thermoplastic polyurethane elastomer film and below a melting temperature of said thermoplastic polyurethane elastomer film;
- (c) compressing the layers of film in surface apposition to form an interface therebetween by applying pressure from a die and from said welding platen to said thermoplastic polyurethane elastomer film;
- (d) transmitting radio-frequency energy to the layers of film while said thermoplastic polyurethane elastomer film is under said pressure, welding the film layers at said interface therebetween forming a weld; and
- (e) cooling said weld of the at least two layers of film, wherein said weld is free of holidays, pins holes, charring, burning, and wrinkles.
- 2. A method of polyurethane film welding according to claim 1, wherein said weld has a strength substantially equivalent to said thermoplastic polyurethane elastomer film in unwelded condition.
- 3. A method of polyurethane film welding according to claim 1, wherein said weld has a span of from about two to about ten times the thickness of the polyurethane film.
- 4. A method of polyurethane film welding according to claim 1, wherein said weld has a span of about 3 to 10 times the thickness of the polyurethane film.
- 5. A method of polyurethane film welding according to claim 1, wherein said weld has integrity and continuity sufficient to constitute a biological barrier.
Parent Case Info
This is a divisional of application Ser. No. 08/104,666, filed Aug. 11, 1993, now U.S. Pat. No. 5,469,863.
US Referenced Citations (11)
Foreign Referenced Citations (3)
Number |
Date |
Country |
119013 |
May 1943 |
AUX |
737374 |
Sep 1955 |
GBX |
851703 |
Oct 1955 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Encyclopedia of Polymer Science & Engineering, "Dielectric Heating", vol. 5, pp.1-23, John Wiley & Sons, 1986. |
Divisions (1)
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Number |
Date |
Country |
Parent |
104666 |
Aug 1993 |
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