US4902378A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymer with reduced internal migration
Assignee: 3M Co
•
Filing: 1988-04-27
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Granted: 1990-02-20
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Expires: 2008-04-27
Abstract
Abstract Semicrystalline polymers and copolymers having migratory additives therein can be provided with reduced migration. A surface layer of the polymer of copolymer article is rendered quasi-amorphous and a film less penetrable by said migratory additives than the polymer or copolymer is adhered thereto.
Inventors
- 👤 Andrew J. Ouderkirk
- 👤 John T. Simpson
- 👤 Robert W. Warner
- 👤 Douglas S. Dunn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:05
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/16; B29C71/00; B29C71/0063; C; C08; C08J; C08J7/00; C08J7/04; C08J7/0427; C08J7/043; B29C35/00; B29C35/02; B29C35/08; B29C35/0805; B29C2035/0827; B29K; B29K2027/00; B29K2027/06; B29K2105/00; B29K2105/0005; B29K2995/00; B29K2995/0037; B29K2995/0039; B29K2995/0041; C08J2327/00; C08J2327/02; C08J2327/04; C08J2327/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
139 words
A process for reducing the migration of migratory materials from film comprising a semicrystalline polymer, said process comprising modifying the surface of a semicrystalline polymer by irradiating at least one surface of a semicrystalline polymer composition containing at least one migratory ingredient with radiation which is absorbed by said composition, controlling the intensity and fluence of said radiation exposure so that semicrystalline polymer on said surface is melted and there is ablation or volatilization of less than 0.1% by weight of the total weight of the polymer in melted areas, and allowing said melted polymer to cool at a rate which will form a quasi-amorphous polymeric area on said at least one surface, and then coating said at least one surface with a polymer that is less penetrable by said migratory ingredient in said composition than is said composition.
Claim 2
Dependent Claim
139 words
A process for reducing the migration of migratory materials from film comprising a semicrystalline polymer, said process comprising modifying the surface of a semicrystalline polymer by irradiating at least one surface of a semicrystalline polymer composition containing at least one migratory ingredient with radiation which is absorbed by said composition, controlling the intensity and fluence of said radiation exposure so that semicrystalline polymer on said surface is melted and there is ablation or volatilization of less than 0.1% by weight of the total weight of the polymer in melted areas, and allowing said melted polymer to cool at a rate which will form a quasi-amorphous polymeric area on said at least one surface, and then coating said at least one surface with a polymer that is less penetrable by said migratory ingredient in said composition than is said composition.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein melting occurs to a depth of at least 5 nm and said polymer comprises poly(vinyl chloride).
Claim 4
Dependent Claim
28 words
The process of claim 1 wherein melting occurs to a depth of at least 10 nm, said polymer comprises poly(vinyl chloride) and said migratory material comprises a plasticizer.
Claim 5
Dependent Claim
15 words
The process of claim 1 wherein said second polymer comprises an acrylic polymer or polyurethane.
Claim 6
Dependent Claim
31 words
The process of claim 2 wherein said poly(vinyl chloride) is in the form of a sheet or film and said melting occurs to a depth of from 20 to 250 nm.
Claim 7
Dependent Claim
31 words
The process of claim 3 wherein said poly(vinyl chloride) is in the form of a sheet or film and said melting occurs to a depth of from 20 to 250 nm.
Claim 8
Dependent Claim
31 words
The process of claim 4 wherein said poly(vinyl chloride) is in the form of a sheet or film and said melting occurs to a depth of from 20 to 250 nm.
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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) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |