Patent US4225373A successfully refreshed from Google Patents.
US4225373A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sealing cross-linked thermoplastic materials
Assignee: WR Grace and Co Conn
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Filing: 1976-12-22
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Granted: 1980-09-30
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Expires: 1996-12-22
Abstract
Abstract The strength of a heat seal which bonds irradiatively cross-linkable thermoplastic materials together can be significantly improved by irradiating the seal area after sealing is completed. This technique is especially effective for improving the seal strength of packaging film laminates such as those having a layer of saran and a layer of ethylene vinyl acetate copolymer.
Inventors
- 👤 Anne C. Bieler
- 👤 Milton A. Howe, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:24
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29; B29C; B29C65/00; B29C65/48; B29C65/4805; B29C65/483; B29C65/4845; B29C66/00; B29C66/01; B29C66/03; B29C66/40; B29C66/41; B29C66/43; B29C66/431; B29C66/4312; B29C66/70; B29C66/71; B29C66/72; B29C66/723; B29C66/73; B29C66/737; B29C66/7371; B29C66/73711; B29C66/73715; B29C66/7375; B29C66/73751; B29C66/73752; B29C66/739; B29C66/7392; B29C66/73921; B32B1/00; B32B1/08; B32B27/28; B32B27/30; B32B27/306; B32B27/32; B32B7/00; B32B7/04; C; C08; C08J; C08J5/00; C08J5/12; C08J5/121; B29C35/00; B29C35/02; B29C35/08; B29C35/0866; B29C2035/0877; B29C59/00; B29C59/16; B29C65/02; B29C65/14; B29C65/1403; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/432; B29C71/00; B29C71/04; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/08; B29K2023/083; B29K2023/10; B29K2023/12; B29K2031/00; B29K2031/04; B29K2105/00; B29K2105/0085; B29K2105/24; B29K2995/00; B29K2995/0037; B29K2995/0049; B29L; B29L2009/00; B29L2023/00; B29L2023/001; B32B38/00; B32B2038/0052; B32B2038/0076; B32B2307/00; B32B2307/30; B32B2307/31; B32B2307/70; B32B2307/732; B32B2307/734; B32B2307/736; B32B2310/00; B32B2310/08; B32B2310/14; B32B2597/00; C08J2323/00; C08J2323/02; C08J2323/04; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1005; Y10T428/00; Y10T428/13; Y10T428/1334; Y10T428/1345; Y10T428/31504; Y10T428/31536; Y10T428/31855; Y10T428/31909; Y10T428/31913; Y10T428/3192; Y10T428/31928
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
129 words
A method of improving the closure seal of a flexible receptacle formed from thermoplastic tubing wherein the tubing comprises multi-layer thermoplastic film having a layer of cross-linked ethylene-vinyl acetate copolymer having from about 2% to about 30% vinyl acetate content by weight, said film having a thickness less than about 2.5 mils and said cross-linked ethylene-vinyl acetate copolymer layer forming the inner surface layer or inner wall of said tubing, comprising the steps of: (a) flattening and clamping said tubing so that said cross-linked ethylene-vinyl acetate surface layers are clamped together in direct surface contact with each other; (b) Heating the clamped area so that the surfaces become heat sealed to each other; and, (c) irradiating the heat sealed area to a dosage level of at least 2.0 MR.
Claim 2
Independent Claim
129 words
A method of improving the closure seal of a flexible receptacle formed from thermoplastic tubing wherein the tubing comprises multi-layer thermoplastic film having a layer of cross-linked ethylene-vinyl acetate copolymer having from about 2% to about 30% vinyl acetate content by weight, said film having a thickness less than about 2.5 mils and said cross-linked ethylene-vinyl acetate copolymer layer forming the inner surface layer or inner wall of said tubing, comprising the steps of: (a) flattening and clamping said tubing so that said cross-linked ethylene-vinyl acetate surface layers are clamped together in direct surface contact with each other; (b) Heating the clamped area so that the surfaces become heat sealed to each other; and, (c) irradiating the heat sealed area to a dosage level of at least 2.0 MR.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-30 | 1984-03-31 | 1984-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-30 | 1988-03-31 | 1988-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-30 | 1992-03-31 | 1992-09-30 | $7700.00 | Window Closed / Lapsed |