Patent US4444829A successfully refreshed from Google Patents.
US4444829A
Expired / Lapsed
US
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Polyamide release film for sheet molding compound
Assignee: Honeywell International Inc
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Filing: 1980-12-22
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Granted: 1984-04-24
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Expires: 2000-12-22
Abstract
Abstract Disclosed is a polyamide film of low crystallinity suitable for use in the manufacture of sheet molding compound (SMC). The sheet is produced from a blend comprising a polyamide selected from the group consisting of polyepsiloncaprolactam, polyhexamethylene adipamide or mixtures thereof, and about 10 to 30 wt. %, based on the total weight of said blend, of a polyolefin compound, or copolymer thereof, such as ethylene-vinyl acetate copolymer. The film has a tear strength of at least about 400 grams in the longitudinal direction as measured by ASTM D-1004-66.
Inventors
- 👤 P. Stuart Bollen
- 👤 Alfieri Degrassi
- 👤 William Sacks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 07:19
CPC Classifications
C; C08; C08L; C08L77/00; B; B29; B29C; B29C33/00; B29C33/56; B29C33/68; B29C37/00; B29C37/0067; B29C37/0075; B29C70/00; B29K; B29K2309/00; B29K2309/08; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31725
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
118 words
A polyamide film for use in the manufacture of sheet molding compound wherein said film is of low crystallinity and comprised of a blend of a polyamide selected from the class consisting of polyepsiloncaprolactam, polyhexamethylene adipamide, or mixtures thereof, the polyamide having a crystallinity of less than 35%, and about 10 to 30 weight percent of the blend of a polyolefin component, or copolymer thereof, the polyclefin having a crystallinity of less than 50%, wherein said film is about 0.5 to 5 mils thick and exhibits (a) a Graves tear strength of at least about 400 grams in the longitudinal direction, as determined by ASTM-D-1004-66; and (b) a styrene permeability of below about 200×10 -9 g.-cm/cm 2 -hr.
Claim 2
Dependent Claim
118 words
A polyamide film for use in the manufacture of sheet molding compound wherein said film is of low crystallinity and comprised of a blend of a polyamide selected from the class consisting of polyepsiloncaprolactam, polyhexamethylene adipamide, or mixtures thereof, the polyamide having a crystallinity of less than 35%, and about 10 to 30 weight percent of the blend of a polyolefin component, or copolymer thereof, the polyclefin having a crystallinity of less than 50%, wherein said film is about 0.5 to 5 mils thick and exhibits (a) a Graves tear strength of at least about 400 grams in the longitudinal direction, as determined by ASTM-D-1004-66; and (b) a styrene permeability of below about 200×10 -9 g.-cm/cm 2 -hr.
Claim 3
Dependent Claim
44 words
The film of claim 1 wherein said polyamide is polyepsiloncaprolactam, said polyolefin component is ethylene/vinyl acetate copolymer, present in about 10-15 weight percent of the blend and said film having a Graves tear strength of at least about 400 up to about 800 grams.
Claim 4
Dependent Claim
54 words
The film of claim 1 having a peelability relative to an uncured thermosetting resin which may be packaged therein in a sandwich-like form such that after maintaining said sandwich at 26°-32° C. for 3 days, less than 5% of the contact surface of said film has sheet molding compound thereon after peeling adhered thereto.
Claim 5
Dependent Claim
31 words
The film of claim 1 wherein said polyolefin component, or copolymer thereof, is selected from polyethylene, polypropylene, ethylene/vinyl acetate copolymer, ethylene, ethyl acrylate copolymer, ethylene, methyl acrylate copolymer, or mixtures thereof.
Claim 6
Dependent Claim
12 words
The film of claim 1 wherein said polyolefin is ethylene/vinyl acetate copolymer.
Claim 7
Dependent Claim
23 words
The film of claim 1 wherein said polyolefin component is present in about 10-15 weight percent based on the weight of the blend.
Claim 8
Dependent Claim
16 words
The film of claim 1 wherein said Graves tear strength is about 400 to 800 grams.
Claim 9
Dependent Claim
21 words
The article of claim 13 wherein said film has a styrene permeability of about 0.1 to 20×10 -9 g.cm/cm 2 -hr.
Claim 10
Dependent Claim
18 words
The film of claim 1 wherein said blend further comprises 0.25 to 2.0 weight percent titanium dioxide filler.
Claim 11
Dependent Claim
148 words
A polyamide film for use in the manufacture of sheet molding compound, said film comprising a blend of: (a) polyepsiloncaprolactam, polyhexamethylene adipamide or mixtures thereof, having a crystallinity of between 10-25% and being present in an amount of 85-90 weight percent; (b) an ethylene/vinyl acetate copolymer having a crystallinity of 20-50% and being present in concentrations of 10-15 weight percent; and (c) titanium dioxide present in concentrations of between 0.5 and 1.5 weight percent of the blend; said film exhibiting: (i) a Graves tear strength of at least about 400 grams in the longitudinal direction, as determined by ASTM D-1004-66; (ii) a styrene permeability of below about 200×10 -9 g.cm/cm 2 -hr.; and (iii) a peelability such that after maintaining said sandwich structure at 26°-32° C. for 3 days, less than 5 percent of the contacting surface of said film has sheet molding compound adhered thereto, after peeling.
Claim 12
Dependent Claim
148 words
A polyamide film for use in the manufacture of sheet molding compound, said film comprising a blend of: (a) polyepsiloncaprolactam, polyhexamethylene adipamide or mixtures thereof, having a crystallinity of between 10-25% and being present in an amount of 85-90 weight percent; (b) an ethylene/vinyl acetate copolymer having a crystallinity of 20-50% and being present in concentrations of 10-15 weight percent; and (c) titanium dioxide present in concentrations of between 0.5 and 1.5 weight percent of the blend; said film exhibiting: (i) a Graves tear strength of at least about 400 grams in the longitudinal direction, as determined by ASTM D-1004-66; (ii) a styrene permeability of below about 200×10 -9 g.cm/cm 2 -hr.; and (iii) a peelability such that after maintaining said sandwich structure at 26°-32° C. for 3 days, less than 5 percent of the contacting surface of said film has sheet molding compound adhered thereto, after peeling.
References Cited (Backward Citations)
US3093255A
Cited
US3516961A
Cited
US3373223A
Cited
US3472916A
Cited
US3626026A
Cited
US3923726A
Cited
US3873667A
Cited
DE2140041A1
Cited
US3971866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |