Methods of forming a thinned prepreg sheet

Patent metadata

Field	Value
Publication number	US-2016144607-A1
Application number	US-201414549231-A
Country	US
Kind code	A1
Filing date	Nov 20, 2014
Priority date	Nov 20, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

A method of forming a thinned prepreg sheet is disclosed. The method comprises providing a first precursor sheet comprising reinforcement fibers impregnated with a matrix resin in a first state. The method also comprises forming a second precursor sheet having a first thickness by cooling the first precursor sheet until the matrix resin is transformed from the first state to a second state. The method further comprises forming a crushed sheet comprising interstices having an average size by crushing the second precursor sheet, where the crushed sheet has a second thickness. The method also comprises forming the thinned prepreg sheet by heating the crushed sheet until the matrix resin is transformed from the second state to a third state. The thinned prepreg sheet has a third thickness less than the first thickness of the second precursor sheet.

First claim

1 . A method ( 200 ) of forming a thinned prepreg sheet ( 100 ), the method comprising:
providing a first precursor sheet ( 102 ) comprising reinforcement fibers ( 104 ) impregnated with a matrix resin ( 106 ) in a first state; forming a second precursor sheet ( 110 ) having a first thickness ( 112 ) by cooling the first precursor sheet ( 102 ) until the matrix resin ( 106 ) is transformed from the first state to a second state; forming a crushed sheet ( 120 ) comprising interstices ( 128 ) having an average size, wherein the crushed sheet ( 120 ) has a second thickness ( 122 ), by crushing the second precursor sheet ( 110 ); and forming the thinned prepreg sheet ( 100 ), wherein the thinned prepreg sheet ( 100 ) has a third thickness ( 132 ) less than the first thickness ( 112 ) of the second precursor sheet ( 110 ), by heating the crushed sheet ( 120 ) until the matrix resin ( 106 ) is transformed from the second state to a third state.

2 . The method ( 200 ) according to claim 1 , wherein, in the first state, the matrix resin ( 106 ) is uncured.

3 . The method ( 200 ) according to claim 1 , wherein providing the first precursor sheet ( 102 ) comprises impregnating the reinforcement fibers ( 104 ) with the matrix resin ( 106 ) in the first state.

4 . The method ( 200 ) according to claim 3 , wherein, in the first state, the matrix resin ( 106 ) is sufficiently flowable to impregnate the reinforcement fibers ( 104 ).

5 . The method ( 200 ) according to claim 1 , wherein providing the first precursor sheet ( 102 ) comprises providing a prepreg sheet.

6 . The method ( 200 ) according to claim 5 , wherein, in the first state, the matrix resin ( 106 ) is partially cured.

7 . The method ( 200 ) according to claim 1 , wherein, in the second state, the matrix resin ( 106 ) is crushable.

8 . The method ( 200 ) according to claim 1 , wherein, in the third state, the matrix resin ( 106 ) is sufficiently flowable to fill the interstices ( 128 ) of the crushed sheet ( 120 ).

9 .- 13 . (canceled)

14 . The method ( 200 ) according to claim 1 , wherein cooling the first precursor sheet ( 102 ) until the matrix resin ( 106 ) is transformed from the first state to the second state comprises freezing the first precursor sheet ( 102 ).

15 .- 16 . (canceled)

17 . The method ( 200 ) according to claim 1 , wherein forming the crushed sheet ( 120 ) further comprises crushing the second precursor sheet ( 110 ) into fragments ( 126 ) partially separated by the interstices ( 128 ).

18 . The method ( 200 ) according to claim 17 , wherein forming the crushed sheet ( 120 ) further comprises spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along a plane.

19 . The method ( 200 ) according to claim 18 , wherein spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along the plane comprises maintaining the average size of the interstices ( 128 ) between the fragments ( 126 ).

20 . The method ( 200 ) according to claim 17 , wherein spreading the fragments ( 126 ) of the second precursor sheet ( 110 ) along the plane comprises vibrating the fragments ( 126 ).

21 . The method ( 200 ) according to claim 17 , wherein forming the crushed sheet ( 120 ) further comprises applying a compressive force to the second precursor sheet ( 110 ) with a press ( 130 ).

22 . The method ( 200 ) according to claim 21 , wherein forming the crushed sheet ( 120 ) further comprises vibrating the press ( 130 ).

23 . The method ( 200 ) according to claim 21 , wherein forming the crushed sheet ( 120 ) further comprises advancing the press ( 130 ) along a surface ( 136 ) of the second precursor sheet ( 110 ).

24 . The method ( 200 ) according to claim 23 , wherein advancing the press ( 130 ) along the surface ( 136 ) of the second precursor sheet ( 110 ) comprises rolling the press ( 130 ) along the surface ( 136 ).

25 .- 34 . (canceled)

35 . The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises melting the matrix resin ( 106 ) of the crushed sheet ( 120 ).

36 . The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises consolidating the crushed sheet ( 120 ).

37 .- 38 . (canceled)

39 . The method ( 200 ) according to claim 1 , wherein heating the crushed sheet ( 120 ) comprises filling the interstices ( 128 ) in the crushed sheet ( 120 ) with the matrix resin ( 106 ) of the crushed sheet ( 120 ).

40 .- 42 . (canceled)

Assignees

• Boeing Co

Inventors

• Humfeld Keith Daniel

Classifications

• B32B38/08

  Impregnating · CPC title

• B32B37/08 Primary

  characterised by the cooling method · CPC title

• B32B2038/0024

  Crushing · CPC title

• C08J5/24 Primary

  Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs · CPC title

• B29C70/465

  and impregnating by melting a solid material, e.g. sheets, powders of fibres · CPC title