Patent US4940736A successfully refreshed from Google Patents.
US4940736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of low density polypropylene foam
Assignee: BP Corp North America Inc
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Filing: 1988-09-12
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Granted: 1990-07-10
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Expires: 2008-09-12
Abstract
Abstract A method of producing a foamed product having a density less than 0.2 g/cm 3 , which comprises foaming a composition comprising a major proportion of a low viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of less than 2×10 3 poise and a minor proportion of a high viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of greater than 2.5×10 3 poise.
Inventors
- 👤 Josef Alteepping
- 👤 Juergen P. Nebe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:57
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0061; C08J9/04; C08J9/12; C08J9/14; C08J9/143; C08J9/147; C08L; C08L23/00; C08L23/02; C08L23/10; C08L23/12; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; C08J2423/00; C08L2205/00; C08L2205/02; Y; Y10; Y10S; Y10S521/00; Y10S521/91
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
84 words
A method of producing a foamed product having a density less than 0.2 g/cm 3 which comprises foaming a composition comprising a major proportion of a low viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of less than 2×10 3 poise and a minor proportion of a high viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of greater than 2.5×10 3 poise.
Claim 2
Independent Claim
84 words
A method of producing a foamed product having a density less than 0.2 g/cm 3 which comprises foaming a composition comprising a major proportion of a low viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of less than 2×10 3 poise and a minor proportion of a high viscosity polypropylene component having a melt viscosity (at 190° C. and a shear rate of 1000 sec -1 ) of greater than 2.5×10 3 poise.
Claim 3
Dependent Claim
25 words
The method according to claim 1 wherein the low viscosity polypropylene component has a weight average molecular weight in the range from 100,000 to 500,000.
Claim 4
Dependent Claim
25 words
The method according to claim 1 wherein the low viscosity polypropylene component has a weight average molecular weight in the range from 200,000 to 350,000.
Claim 5
Dependent Claim
18 words
The method according to claim 1 wherein the low viscosity polypropylene component has a dispersivity less than 5.
Claim 6
Dependent Claim
20 words
The method according to claim 1 wherein the low viscosity polypropylene component has a dispersivity of from 2 to 5.
Claim 7
Dependent Claim
19 words
The method according to claim 1 wherein the high viscosity polypropylene component has a molecular weight greater than 500,000.
Claim 8
Dependent Claim
22 words
The method according to claim 6 wherein the high viscosity polypropylene component has a molecular weight in the range 1,000,000 to 2,000,000.
Claim 9
Dependent Claim
19 words
The method according to claim 1 wherein the high viscosity polypropylene component has a dispersivity of less than 5.
Claim 10
Dependent Claim
22 words
The method according to claim 8 wherein the high viscosity polypropylene component has a dispersivity in the range from 2 to 5.
Claim 11
Dependent Claim
50 words
The method according to claim 1 wherein said composition comprises from 70 to 90 weight per cent of said low viscosity polypropylene component and from 30 to 10 weight per cent of said high viscosity polypropylene component based on the total weight of said low and high viscosity polypropylene components.
Claim 12
Dependent Claim
28 words
The method according to claim 1 wherein said composition comprises from 5 to 40 weight per cent of atactic polypropylene based on the total weight of the composition.
Claim 13
Dependent Claim
40 words
The method according to claim 11 wherein the composition is formed by mixing high and low viscosity polypropylene components each comprising from 60 to 95 weight per cent isotactic polypropylene and from 40 to 5 weight per cent atactic polypropylene.
Claim 14
Dependent Claim
62 words
The method according to claim 12 wherein the atactic polypropylene contained in the low viscosity polypropylene component has a weight average molecular weight in the range from 100,000 to 500,000 and a dispersivity less than 5 and the atactic polypropylene contained in the high viscosity polypropylene component has a weight average molecular weight greater than 500,000 and a dispersivity less than 5.
Claim 15
Dependent Claim
91 words
The method according to claim 1 wherein the composition comprises 88 weight per cent of a low viscosity polypropylene component comprising a polypropylene having a weight average molecular weight of 280,000 and a dispersivity of 2 and 12 weight per cent of a high viscosity polypropylene component comprising a polypropylene having a weight average molecular weight of 1,800,000 and a dispersivity of 2.5, and wherein the low viscosity polypropylene component and the high viscosity polypropylene component each comprises 85 weight per cent isotactic polypropylene and 15 weight per cent atactic polypropylene.
Claim 16
Dependent Claim
14 words
The method according to claim 1 wherein the foaming composition includes a blowing agent.
Claim 17
Dependent Claim
16 words
The method according to claim 15 wherein the blowing agent comprises a fluorochlorocarbon or fluorochlorocarbon mixture.
Claim 18
Dependent Claim
16 words
The method according to claim 16 wherein said mixture comprises a mixture of monofluorotrichloromethane and tetrafluorodichloroethane.
Claim 19
Dependent Claim
22 words
The method according to claim 17 wherein the weight ratio of monofluorotrichloromethane and tetrafluorodichloroethane is in the range of 20:80 to 50:50.
Claim 20
Dependent Claim
34 words
The method according to claim 1 wherein the foaming composition contains a nucleating agent comprising a mixture of sodium bicarbonate and citric acid or a mixture of sodium bicarbonate and citric acid with talc.
Claim 21
Independent Claim
62 words
A method of producing a foamed product having a density less than 0.2 g/cm 3 which comprises foaming a composition comprising a major proportion of a low viscosity polypropylene component having a weight average molecular weight in the range from 100,000 to 500,000 and a minor proportion of a high viscosity polypropylene component having a weight average molecular weight greater than 500,000.
Claim 22
Independent Claim
62 words
A method of producing a foamed product having a density less than 0.2 g/cm 3 which comprises foaming a composition comprising a major proportion of a low viscosity polypropylene component having a weight average molecular weight in the range from 100,000 to 500,000 and a minor proportion of a high viscosity polypropylene component having a weight average molecular weight greater than 500,000.
Claim 23
Dependent Claim
13 words
The method of claim 20 wherein the foaming is carried out by extrusion.
Claim 24
Dependent Claim
45 words
The method of claim 20 wherein the low viscosity polypropylene component is present in the amount of 70 to 90 weight percent of the composition and the high viscosity polypropylene component is present in the amount of 10 to 30 weight percent of the composition.
Claim 25
Dependent Claim
17 words
The method of claim 22 wherein the low viscosity polypropylene component has a dispersivity less than 5.
Claim 26
Dependent Claim
18 words
The method of claim 22 wherein the high viscosity polypropylene component has a dispersivity of less than 5.
Claim 27
Dependent Claim
13 words
The method of claim 1 wherein the foaming is carried out by extrusion.
References Cited (Backward Citations)
US3607796A
Cited
US3846349A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |