Non-woven flexible multiply towpreg fabric

• US 5,198,281 A
• Filed: 03/09/1992
• Issued: 03/30/1993
• Est. Priority Date: 04/17/1989
• Status: Expired due to Term

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Muzzy, John D., Colton, Jonathan S.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US07/848,093
• Time in Patent Office: 386 Days
• Field of Search: 428/102, 428/105, 428/114, 428/198, 428/296, 428/300, 156/148, 156/163, 156/180, 156/290, 156/308.2, 264/136
• US Class Current: 428/102
• CPC Class Codes: B29B 15/12 of reinforcements of indefinite length
• CPC Class Codes: B29C 70/20 oriented in a single direction, e.g. roofing or other parallel fibres B29C70/083, B29C70/226 take precedence
• CPC Class Codes: B29C 70/50 for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
• CPC Class Codes: B29C 70/504 using rollers or pressure bands for corrugating B29C53/22
• CPC Class Codes: B29K 2105/0067 Melt
• CPC Class Codes: B29K 2105/0088 Blends of polymers
• CPC Class Codes: B29K 2105/251 Particles, powder or granules expandable particles B29K2105/046
• CPC Class Codes: B29K 2105/26 Scrap or recycled material
• CPC Class Codes: B63B 15/0083 Masts for sailing ships or boats
• CPC Class Codes: C04B 41/4584 Coating or impregnating of particulate or fibrous ceramic material C04B20/10, C04B35/628 take precedence
• CPC Class Codes: D01F 11/14 with organic compounds, e.g. macromolecular compounds
• CPC Class Codes: D01F 11/16 by physicochemical methods
• CPC Class Codes: D06M 23/08 Processes in which the treating agent is applied in powder or granular form adhesives for multi-layer textile fabrics D06M17/00
• CPC Class Codes: Y10T 428/24033 including stitching and discrete fastener[s], coating or bond
• CPC Class Codes: Y10T 428/24058 including grain, strips, or filamentary elements in respective layers or components in angular relation
• CPC Class Codes: Y10T 428/24132 including grain, strips, or filamentary elements in different layers or components parallel
• CPC Class Codes: Y10T 428/24826 Spot bonds connect components
• CPC Class Codes: Y10T 442/659 Including an additional nonwoven fabric
• CPC Class Codes: Y10T 442/667 Needled
• CPC Class Codes: Y10T 442/671 Multiple nonwoven fabric layers composed of the same polymeric strand or fiber material
• CPC Class Codes: Y10T 442/69 : Autogenously bonded nonwoven fabric

Abstract

A non-woven towpreg fabric and a method of production therefor. The non-woven towpreg fabric is fabricated from a plurality of flexible, multiply towpregs, comprising towpreg plies which comprise reinforcing filaments substantially wetout by a matrix forming material, which then are bonded together to form the fabric. The method of production for the non-woven towpreg fabric involves spreading the reinforcing filaments, coating the reinforcing filaments with the matrix forming material in a manner causing interfacial adhesion, forming the towpreg plies by heating the matrix forming material until the matrix forming material liquefies and coats the reinforcing filaments, cooling the towpreg plies in a manner while said towpregs remain substantially unconsolidated until the matrix forming material solidifies, overlapping a plurality of the towpreg plies, and bonding the towpreg plies together. Multidimensional fabrics, preforms and composite articles also can be formed by this invention.

Claims

1. A non-woven towpreg fabric comprising a plurality of flexible, multiply towpregs, comprising towpreg plies, said towpregs comprising reinforcing filaments and matrix forming material, said reinforcing filaments being substantially wet-out by said matrix forming material while said towpregs remain substantially unconsolidated, wherein said towpregs are arranged in overlapping layers comprising at least one towpreg and are bonded together resulting in said non-woven towpreg fabric.

2. The non-woven towpreg fabric as claimed in claim 1, wherein said layers of towpregs are overlapped in a unidirectional configuration.

3. The non-woven towpreg fabric as claimed n claim 1, wherein said layers of towpregs are overlapped in a multidirectional configuration.

4. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using hot melt bonding.

5. The non-woven towpreg fabric as claimed in claim 4, wherein said towpregs are hot melt bonded at selected points along the towpreg plies.

6. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using stitching.

7. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using needle punching.

8. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using pressure melting of the matrix forming material.

9. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using binder filament interleaving.

10. The non-woven towpreg fabric as claimed in claim 1, wherein said towpregs are bonded together using binder yarn interleaving.

11. A multidimensional preform fabricated from a non-woven towpreg fabric comprising a plurality of flexible, multiply towpregs, said towpregs comprising reinforcing filaments and matrix forming material, said reinforcing filaments being substantially wetout by said matrix forming material while said towpregs remain substantially unconsolidated, wherein said towpregs are arranged in overlapping layers comprising at least one towpreg and are bonded together in a desired configuration to form said preform.

12. The non-woven towpreg fabric as claimed in claim 11, wherein said towpregs have an average thickness less than 75 microns.

13. The non-woven towpreg fabric as claimed in claim 11, wherein said towpregs have an average thickness of between about 10 to 50 microns.

14. The non-woven towpreg fabric as claimed in claim 12, wherein said towpregs have an average thickness of between about 15 to 30 microns.

15. A composite article fabricated from a plurality of flexible, multiply towpregs, comprising towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, said reinforcing filaments being substantially wetout by said matrix forming material while said towpregs remain substantially unconsolidated, wherein said plurality of towpregs are arranged in a desired configuration and bonded together resulting in a contoured preform having the general configuration of said composite article, and said preform is further acted upon to form said composite article.

16. A method for the production of a non-woven towpreg fabric comprising a plurality of flexible, multiply towpregs, comprising towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material, comprising the steps of:

(a) spreading said reinforcing filaments to expose individually substantially all of said reinforcing filaments;

(b) coating said reinforcing filaments with said matrix forming material in a manner causing interfacial adhesion of said matrix forming material to said reinforcing filaments;

(c) forming said towpreg plies by heating said matrix forming material contacting said reinforcing filaments until said matrix forming material liquefies and coats said reinforcing filaments;

(d) cooling said towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until said matrix forming material solidifies so as to form said flexible, multiply towpregs;

(e) overlapping layers comprising at least one of said towpregs in a manner such that a multilayer configuration of towpregs is formed; and

(f) bonding said overlapped towpregs together to form said non-woven towpreg fabric.

17. The method as claimed in claim 16, wherein said layers of towpregs are overlapped in a unidirectional configuration in step (e).

18. The method as claimed in claim 16, wherein said layers of towpregs are overlapped in a multidirectional configuration in step (e).

19. The method as claimed in claim 16, wherein said towpregs are bonded together using hot melt bonding in step (f).

20. The method as claimed in claim 16, wherein said towpregs are bonded together using stitching in step (f).

21. The method as claimed in claim 16, wherein said towpregs are bonded together using needle punching.

22. The method as claimed in claim 16, wherein said towpregs are bonded together using binder filament interleaving.

23. The method as claimed in claim 16, wherein said towpregs are bonded together using binder yarn interleaving.

24. The method as claimed in claim 16, wherein said spreading is lateral.

25. The method as claimed in claim 16, wherein steps (e) and (f) are repeated a plurality of times.

26. The method as claimed in claim 16, wherein step (c) is accomplished by pultrusion.

30. The method as claimed in claim 26, wherein steps (e), (f) and (g) are repeated a plurality of times.

27. A method for the production of a multidimensional preform comprising a plurality of flexible, multiply towpregs, comprising towpreg plies, said towpreg plies comprising reinforcing filaments and matrix forming material comprising the steps of:

(a) spreading said reinforcing filaments to expose individually substantially all of said reinforcing filaments;

(b) coating said reinforcing filaments with said matrix forming material in a manner causing interfacial adhesion of said matrix forming material to said reinforcing filaments;

(c) forming said towpreg plies by heating said matrix forming material contacting said reinforcing filaments until said matrix forming material liquefies and coats said reinforcing filaments;

(d) cooling said towpreg plies in a manner such that substantial cohesion between neighboring towpreg plies is prevented until said matrix forming material solidifies so as to form said flexible, multiply towpregs;

(e) overlapping layers comprising at least one of said towpregs in a manner such that a multilayer configuration of towpregs is formed;

(f) arranging said towpregs into a desired preform configuration; and

(g) bonding said towpregs together so as to form said preform.

28. The method as claimed in claim 27, wherein steps (e), (f) and (g) are carried out in any order.

29. The method as claimed in claim 27, wherein any or all of steps (e), (f) and (g) are carried out simultaneously.

31. The method as claimed in claim 27, wherein step (c) is accomplished by pultrusion.