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US4638015A
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US
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Expanded polypropylene films
Assignee: MONTEFINA SA FELUY BELGIUM A CORP OF BELGIUM
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Filing: 1985-09-30
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Granted: 1987-01-20
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Expires: 2005-09-30
Abstract
Abstract Disclosed are films made of expanded polypropylene, which have a uniform specific gravity d of from about 4.25x10-6 to about 6.50x10-6 Newton/mm3, a crystallization temperature of from about 115 DEG C. to about 135 DEG C. and an elastic modulus Me expressed in Newton/mm3 such that the ratio Me:d is from about 1.6x108 to about 2.0x108 mm.
Inventors
- 👤 Jean-Noel M. Bertrand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:07
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/06; C08J9/0014; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; Y; Y10; Y10S; Y10S521/00; Y10S521/908
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
64 words
Films made of expanded polypropylene characterized by having (i) a uniform specific gravity d of from about 4.25×10 -6 to about 6.50×10 -6 Newton/mm 3 , (ii) a crystallization temperature of from about 115° C. to about 135° C., and (iii) an elastic modulus Me expressed in Newton/mm 2 such that the ratio Me:d is from about 1.6×10 8 to about 2.0×10 8 mm.
Claim 2
Dependent Claim
64 words
Films made of expanded polypropylene characterized by having (i) a uniform specific gravity d of from about 4.25×10 -6 to about 6.50×10 -6 Newton/mm 3 , (ii) a crystallization temperature of from about 115° C. to about 135° C., and (iii) an elastic modulus Me expressed in Newton/mm 2 such that the ratio Me:d is from about 1.6×10 8 to about 2.0×10 8 mm.
Claim 3
Dependent Claim
20 words
Films according to claim 1, characterized by having a crystallization temperature of from about 115° C. to about 130° C.
Claim 4
Dependent Claim
20 words
Films according to claim 1, having a density of from about 4.5×10 -6 to about 4.7×10 -6 N/mm 3 .
Claim 5
Dependent Claim
22 words
Films according to claim 1 having a tensile strength at 5% elongation of from about 10.75 to about 11.25 N/mm 2 .
Claim 6
Dependent Claim
21 words
Films according to claim 1 having a tensile strength at break of from about 11.0 to about 11.5 N/mm 2 .
Claim 7
Dependent Claim
32 words
Expanded polypropylene films of claim 1 obtained from a polymeric composition comprising: (a) isotactic polypropylene; (b) an agent for increasing the crystallization speed of said polymeric composition; and (c) a blowing agent.
Claim 8
Dependent Claim
14 words
The films of claim 6 wherein said polymeric composition further comprises a nucleating agent.
Claim 9
Dependent Claim
62 words
The films of claim 6 wherein the agent for increasing the crystallization speed is selected from the group consisting of dibenzilidene sorbitol, sodium bis (4-tert-butyl-phenol) phosphate, sodium benzoate, a mixture comprising a monocarboxylic aromatic acid or a polycarboxylic aliphatic acid and a silicate or an alumino-silicate of a metal of Group I or II of the Periodic System, and any mixture thereof.
Claim 10
Dependent Claim
28 words
The films of claim 8 wherein said agent is present in an amount of from about 500 ppm to about 5000 ppm based on the weight of polypropylene.
Claim 11
Dependent Claim
42 words
The films of claim 6 wherein the isotactic polypropylene is selected from the group consisting of propylene homopolymer, a copolymer of propylene and not greater than 10 wt. % of an alpha-olefin having up to 6 carbon atoms, or any mixture thereof.
Claim 12
Dependent Claim
16 words
The films of claim 6 characterized by having a variation in density of less than 5%.
Claim 13
Dependent Claim
22 words
Films according to claim 6 having a tensile strength at 5% elongation of from about 10.75 to about 11.25 N/mm 2 .
Claim 14
Dependent Claim
21 words
Films according to claim 6 having a tensile strength at break of from about 11.0 to about 11.5 N/mm 2 .
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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) | 1990-01-19 | 1990-07-21 | 1991-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-19 | 1994-07-21 | 1995-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-19 | 1998-07-21 | 1999-01-20 | $7700.00 | Window Closed / Lapsed |