US4229473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Partial interlaminar separation system for composites
Assignee: National Aeronautics and Space Administration
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Filing: 1978-03-24
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Granted: 1980-10-21
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Expires: 1998-03-24
Abstract
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.
Inventors
- 👤 Wolf Elber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:40
CPC Classifications
B; B29; B29C; B29C70/00; B29C70/04; B29C70/28; B29C70/30; B29C70/34; B29C70/06; B29C70/08; B29C70/086; B32; B32B; B32B27/00; B32B27/12; B32B7/00; B32B7/04; B29K; B29K2063/00; B29K2067/00; B29K2067/06; B29K2101/00; B29K2101/12; B29K2105/00; B29K2105/06; B29K2105/08; B29K2105/10; B29K2105/101; B29K2105/108; B29K2307/00; Y; Y10; Y10S; Y10S428/00; Y10S428/902; Y10T; Y10T428/00; Y10T428/24; Y10T428/24058; Y10T428/24124; Y10T428/24132; Y10T428/24273; Y10T428/24322; Y10T428/24331; Y10T428/24339; Y10T428/24347; Y10T428/31504; Y10T428/31511; Y10T428/31786
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
81 words
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.
Claim 2
Dependent Claim
81 words
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.
Claim 3
Dependent Claim
21 words
The composite laminate of claim 1 wherein the prepreg fibers in each lamina of the composite are unidirectionally disposed graphite fibers.
Claim 4
Dependent Claim
28 words
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.
Claim 5
Dependent Claim
14 words
The composite laminate of claim 3 wherein said thin polyester film is polyethylene terepthalate.
Claim 6
Dependent Claim
28 words
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.
Claim 7
Dependent Claim
22 words
The composite laminate of claim 1 wherein a layer of perforated polyester film is disposed between each lamina of the composite laminate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |