US4362844A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biaxially stretched polypropylene-based plastic products, and process for making such products
Assignee: Stamicarbon BV
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Filing: 1981-05-26
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Granted: 1982-12-07
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Expires: 2001-05-26
Abstract
Abstract The invention relates to polypropylene-based plastic products, biaxially stretched below the melting point, wherein the plastic consists substantially of a mixture of 60-95 % by weight of a substantially crystalline propylene polymer and 5-40 % by weight of an ethylene-vinylalcohol copolymer, and to a process for making such products. According to the invention an ethylene-vinylalcohol copolymer is used having a melting point which is at most equal to that of the propylene polymer, preferably 0-20 K below the melting point of the propylene polymer. The invention provides biaxially stretched polypropylene products having an outstandingly good gas impermeability while retaining their good properties in respect of optical clarity, mechanical properties and simplicity of production.
Inventors
- 👤 Pieter J. Lemstra
- 👤 Marcellus J. P. Houben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:29
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B29; B29C; B29C51/00; B29C51/002; C08L; C08L23/00; C08L23/02; C08L23/10; C08L23/12; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; C08L23/04; C08L23/08; C08L23/0846; C08L23/0853; C08L23/0861
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
58 words
Plastic product based on polypropylene, biaxially stretched below the melting point, wherein the plastic consists substantially of a mixture of 60-95% by weight of a substantially crystalline propylene polymer and 5-40% by weight of an ethylene-vinylalcohol copolymer, characterized in that the ethylene-vinylalcohol copolymer has a melting point which is at most equal to that of the propylene polymer.
Claim 2
Dependent Claim
58 words
Plastic product based on polypropylene, biaxially stretched below the melting point, wherein the plastic consists substantially of a mixture of 60-95% by weight of a substantially crystalline propylene polymer and 5-40% by weight of an ethylene-vinylalcohol copolymer, characterized in that the ethylene-vinylalcohol copolymer has a melting point which is at most equal to that of the propylene polymer.
Claim 3
Dependent Claim
31 words
Product according to claim 1, characterized in that the ethylene-vinylalcohol copolymer has a melting point that is not more than 20 K lower than the melting point of the propylene polymer.
Claim 4
Dependent Claim
21 words
Product according to claim 1 or 2, characterized in that the ethylene content of the ethylene-vinylalcohol copolymer is 30-55 mol %.
Claim 5
Dependent Claim
19 words
Product according to claim 3, characterized in that the ethylene content of the ethylene-vinylalcohol copolymer is 35-50 mol %.
Claim 6
Dependent Claim
24 words
Product according to any one of the claims 1-4, characterized in that the ethylene-vinylalcohol copolymer has a degree of saponification of at least 95%.
Claim 7
Dependent Claim
22 words
Product according to any one of the claims 1-5, characterized in that the plastics mixture contains 10-30% by weight of ethylene-vinylalcohol copolymer.
Claim 8
Dependent Claim
23 words
Product according to any one of the claims 1-6, characterized in that the plastics mixture contains 1-5% by weight of a coupling agent.
Claim 9
Dependent Claim
27 words
Product according to any one of the claims 1-7, characterized in that the melt index of the ethylene-vinylalcohol copolymer is higher than that of the propylene polymer.
Claim 10
Dependent Claim
73 words
Process of making plastic products based on polypropylene, wherein the plastic used is a mixture substantially consisting of 60-95% by weight of a substantially crystalline propylene polymer and 5-40% by weight of an ethylene-vinylalcohol copolymer, and in which process the plastic is biaxially stretched below the melting point of the propylene polymer, characterized in that an ethylene-vinylalcohol copolymer is used having a melting point at most equal to that of the propylene polymer.
Claim 11
Dependent Claim
73 words
Process of making plastic products based on polypropylene, wherein the plastic used is a mixture substantially consisting of 60-95% by weight of a substantially crystalline propylene polymer and 5-40% by weight of an ethylene-vinylalcohol copolymer, and in which process the plastic is biaxially stretched below the melting point of the propylene polymer, characterized in that an ethylene-vinylalcohol copolymer is used having a melting point at most equal to that of the propylene polymer.
References Cited (Backward Citations)
US3975463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-06 | 1986-06-07 | 1986-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-06 | 1990-06-07 | 1990-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-06 | 1994-06-07 | 1994-12-07 | $7700.00 | Window Closed / Lapsed |