Partial interlaminar separation system for composites

• US 4,229,473 A
• Filed: 03/24/1978
• Issued: 10/21/1980
• Est. Priority Date: 03/24/1978
• Status: Expired due to Term

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Elber, Wolf
• Primary Examiner(s): Thibodeau, Paul J.
• Application Number:
  US05/889,671
• Time in Patent Office: 942 Days
• Field of Search: 428/105, 428/110, 428/113, 428/139, 428/140, 428/902, 428/413, 428/480, 428/481, 428/114, 156/166, 156/313, 156/252
• US Class Current: 428/113
• CPC Class Codes: B29C 70/086 and with one or more layers of pure plastics material, e.g. foam layers applying a non-preformed coating, e.g. a gel-coat, B29C37/0025; with foam blocks B29C70/86
• CPC Class Codes: B29C 70/34 and shaping or impregnating by compression , i.e. combined with compressing after the lay-up operation
• CPC Class Codes: B29K 2063/00 Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2067/06 Unsaturated polyesters
• CPC Class Codes: B29K 2101/12 Thermoplastic materials
• CPC Class Codes: B29K 2105/108 arranged in parallel planes and crossing at substantial angles B29K2105/206 takes precedence
• CPC Class Codes: B29K 2307/00 Use of elements other than metals as reinforcement
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 7/04 Interconnection of layers
• CPC Class Codes: Y10S 428/902 High modulus filament or fiber
• CPC Class Codes: Y10T 428/24124 Fibers
• CPC Class Codes: Y10T 428/24132 including grain, strips, or filamentary elements in different layers or components parallel
• CPC Class Codes: Y10T 428/24331 including nonapertured component
• CPC Class Codes: Y10T 428/24347 From both sides
• CPC Class Codes: Y10T 428/31511 Of epoxy ether
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]

Abstract

This invention relates to an interlaminar separation system for composites wherein a thin layer of a perforated foil film is interposed between adjacent laminae of a composite formed from prepreg tapes to thereby permit laminae adherence through the perforations and produce a composite structure having improved physical property characteristics.

Claims

1. A composite laminate having improved fracture resistance comprising:

a plurality of prepreg tape segments vertically stacked with controlled fiber orientation in each stacked layer and cured into a composite laminate;

at least one layer of a thin perforated polyester foil film disposed between two adjacent layers of prepreg tape and wherein the adjacent prepreg tape layers are permanently bonded to each other through the perforations in said polyester foil film when the laminate is cured, said laminae being otherwise essentially unbonded.

2. The composite laminate of claim 1 wherein the prepreg fibers in each lamina of the composite are unidirectionally disposed graphite fibers.

3. The composite laminate of claim 2 wherein the prepreg fibers in each lamina are selectively disposed 0°

, ±

45°

, and 90°

relative to the fibers in an adjacent layer.

4. The composite laminate of claim 3 wherein said thin polyester film is polyethylene terepthalate.

5. The composite laminate of claim 1 wherein the open area in said perforated polyester foil film is in the range of 30-45% of the available film surface area.

6. The composite laminate of claim 1 wherein a layer of perforated polyester film is disposed between each lamina of the composite laminate.