AIRBAG FABRICS WOVEN FROM SLIT-FILM POLYMERIC TAPES

• US 20120205901A1
• Filed: 07/31/2009
• Published: 08/16/2012
• Est. Priority Date: 08/07/2008
• Status: Active Grant

• Current Assignee: INV Performance Materials LLC
• Original Assignee: Invista North America Sarl (Invista)
• Inventors: Westoby, Scott
• Granted Patent: US 9,157,173 B2
• Time in Patent Office: Days
• US Class Current: 280/743.2
• CPC Class Codes: B29C 48/0018 combined with shaping by orienting, stretching or shrinking, e.g. film blowing B29C48/0017 takes precedence
• CPC Class Codes: B29C 48/0022 combined with cutting
• CPC Class Codes: B60R 2021/23509 Fabric
• CPC Class Codes: B60R 2021/23519 Resin for coating fabric B60R2021/23514
• CPC Class Codes: B60R 21/2338 Tethers
• CPC Class Codes: B60R 21/235 characterised by their material
• CPC Class Codes: D01D 5/423 by fibrillation of films or filaments
• CPC Class Codes: D01D 5/426 by cutting films
• CPC Class Codes: D02G 3/446 Yarns or threads for use in automotive applications
• CPC Class Codes: D03D 1/02 Inflatable articles
• CPC Class Codes: D03D 13/008 characterised by weave density or surface weight
• CPC Class Codes: D03D 15/283 synthetic polymer-based, e.g. polyamide or polyester fibres cellulose-based artificial fibres D03D15/225
• CPC Class Codes: D03D 15/46 Flat yarns, e.g. tapes or films
• CPC Class Codes: D03D 15/573 Tensile strength
• CPC Class Codes: D10B 2331/02 polyamides D10B2331/08 takes precedence
• CPC Class Codes: D10B 2401/041 thermoplastic; thermosetting
• CPC Class Codes: D10B 2401/062 stiff, shape retention
• CPC Class Codes: D10B 2401/063 high strength
• CPC Class Codes: D10B 2505/124 Air bags
• CPC Class Codes: Y10T 442/2008 Fabric composed of a fiber or strand which is of specific structural definition

Abstract

Disclosed herein is the preparation of woven fabrics suitable for use in manufacturing vehicle airbags. Such fabrics are woven from a plurality of polymeric, e.g., polyamide, warp and weft tapes which have preferably been slitted, preferably in the machine direction, from a thermoplastic polymer film, and preferably from such a film which has been drawn at least in the machine direction. The resulting fabrics exhibit both the relatively low basis weight, stiffness and small packing volume typical of nylon films, and the relatively high tear strength and high damage tolerance of yarn-based woven airbag fabrics.

Claims

1. A woven fabric suitable for use in manufacturing vehicle airbags, said fabric being woven from a plurality of machine direction-drawn thermoplastic polymer warp tapes having a width of from about 3 to about 15 mm and a plurality of machine direction-drawn thermoplastic polymer weft tapes having a width of from about 3 to about 15 mm;

said machine direction-drawn warp and weft tapes being prepared from a thermoplastic polymer film and having a tensile strength of at least about 200 MPa; and

said fabric having a basis weight of from about 40 grams/m² to about 140 grams/m².

2. A woven fabric according to claim 1 wherein the thermoplastic polymeric film from which said warp and weft tapes are prepared comprises a polyamide film.

3. A woven fabric according to claim 1 wherein said warp and weft tapes are prepared by slitting an at least machine direction-drawn thermoplastic polymeric film having a caliper of from about 80 to about 240 microns prior to drawing.

4. A woven fabric according to claims 1 wherein said thermoplastic polymeric film is machine direction drawn using a draw ratio of from about 2 to about 6 before said warp and weft tapes are prepared therefrom.

5. A woven fabric according to claim 1 wherein said warp and weft tapes are prepared by slitting an undrawn or partially drawn polymer film having a gauge of from about 80 to about 240 microns, and by then machine direction drawing or further drawing said warp and weft tapes.

6. A woven fabric according to claim 1 wherein said warp and weft tapes are drawn or further drawn using a total draw ratio of from about 2 to about 6 after being slit from said polymer film.

7. A woven fabric according to claim 1 wherein said warp and weft tapes are woven in a plain weave or a twill weave pattern.

8. A woven fabric according to any of claims 1 wherein both said warp and said weft tapes have an average width of from about 4 mm to about 10 mm.

9. A woven fabric according to claim 1 wherein said warp and weft tapes both have tensile strength values of at least about 300 MPa.

10. A woven fabric according to claims 1 wherein said warp and weft tapes are prepared from a cast or blown polyamide film comprising nylon 6 or nylon 6,6 polymeric units.

11. A woven fabric according to claim 10 wherein said polyamide film comprises nylon 6 or nylon 6,6 modified with an ethylene copolymer.

12. A woven fabric according to claim 11 wherein said nylon-modifying ethylene copolymer is selected form the group consisting of ethylene/vinyl acetate and ethylene/alkyl (meth)acrylate dipolymers and terpolymers.

13. A woven fabric according to claim 1 which exhibits a grab tensile strength of at least about 1000 Newtons as determined by ASTM D-5034.

14. A woven fabric according to claim 1 which exhibits a warp tongue tear strength of at least about 200 Newtons as determined by ASTM D-2261.

15. A woven fabric according to claim 1 which is coated with an organic coating agent to reduce the air permeability thereof.

16. A woven fabric according to claim 15 wherein said organic coating agent is selected from the group consisting of neoprene, chloroprene, polyurethane and silicone.

17. An airbag suitable for use as a supplementary passenger restraint within a vehicle, said airbag comprising a woven fabric according to claim 1.

18. An airbag according to claim 17 which comprises at least two distinct pieces of fabric.

19. An airbag according to claim 18 wherein said at least two distinct pieces of fabric are adhesively or thermally bonded to each other.

20. An airbag according to claim 19 wherein said fabric pieces are adhesively bonded using an adhesive selected from the group consisting of polyether/polyamide block copolymer adhesives, acrylate/epoxy adhesives, acrylate/silicone adhesives, ethylene/acrylic acid adhesives, polyurethane adhesives, polyester adhesives, polyester/epoxy adhesives, polyolefin rubber adhesives, epoxy/polyolefin adhesives, polyamide adhesives, polyurea adhesives and combinations thereof.

21. Airbag straps, tethers or chutes comprising a woven fabric according claim 1.

25. A process according to claim 23 or claim 21 wherein the tapes in said plurality of tapes are drawn using a draw ratio of from about 2 to about 6.

22. A process for preparing a woven fabric suitable for use in manufacturing vehicle airbags, said process comprising:

A) providing a thermoplastic polymeric film having a machine direction and a caliper of from about 80 to about 240 microns;

B) drawing said film at least in the machine direction using a draw ratio of from about 2 to about 6;

C) slitting said drawn film in the machine direction to form a plurality of thermoplastic polymer tapes each having a width of from about 3 to about 15 mm and a tensile strength of at least about 200 MPa;

D) utilizing said plurality of thermoplastic polymer tapes as both warp and weft tapes to weave a fabric therefrom, said fabric having a basis weight of from about 40 grams/m² to about 140 grams/m².

26. A process according to claim 22 wherein said thermoplastic polymeric film comprises a polyamide film.

27. A process according to claim 22 wherein said warp and weft tapes are woven into a plain weave or a twill weave pattern.

28. A process according to claim 22 wherein said warp and weft tapes have an average width of from about 4 mm to about 10 mm.

29. A process according to claim 22 wherein said warp and weft tapes have a tensile strength of at least about 300 MPa.

30. A process according to claim 22 wherein said thermoplastic polymeric film is a cast or blown film comprising nylon 6 or nylon 6,6 polymeric units.

31. A process according to claim 30 wherein said thermoplastic polymeric film comprises nylon 6 or nylon 6,6 modified with an ethylene copolymer.

32. A process according to claim 31 wherein said nylon-modifying ethylene copolymer is selected from the group consisting of ethylene/vinyl acetate and ethylene/alkyl (meth)acrylate dipolymers and terpolymers.

33. A process according to claim 22 wherein the fabric prepared exhibits a grab tensile strength of at least about 1000 Newtons as determined by ASTM D-5034.

34. A process according to claim 22 wherein the fabric prepared exhibits a warp tongue tear strength of at least about 200 Newtons as determined by ASTM D-2261.

35. A process according to claim 22 which comprises the additional step of coating the formed fabric with an organic coating agent to reduce the air permeability of said fabric.

36. A process according to claim 35 wherein said organic coating agent is selected from the group consisting of neoprene, chloroprene, polyurethane and silicone.

23. A process for preparing a woven fabric suitable for use in manufacturing vehicle airbags, said process comprising:

A) providing a thermoplastic polymeric film having a machine direction and a caliper of from about 80 to about 240 microns;

B) slitting said film to form a plurality of thermoplastic polymer tapes each having a machine direction and a width of from about 3 to about 15 mm;

C) drawing the tapes in said plurality of tapes in the machine direction to the extent necessary to provide substantially all of the tapes within said plurality of tapes with a tensile strength of at least about 200 MPa;

D) utilizing said plurality of thermoplastic polymer tapes as both warp and weft tapes to weave a fabric therefrom, said fabric having a basis weight of from about 40 grams/m² to about 140 grams/m².

24. A process according to claim 23 wherein said plurality of tapes is slit from said thermoplastic polymer film in the machine direction of said film.