US4282076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of visbreaking polypropylene
Assignee: Himont Inc
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Filing: 1979-09-17
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Granted: 1981-08-04
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Expires: 1999-09-17
Abstract
Abstract A process for preparing an environmentally stable plastic composition having narrow molecular weight distribution by visbreaking a propylene polymer using an activated portion of the propylene polymer as a prodegradant. The process includes forming the prodegradant by activating a portion of the propylene polymer either by exposure to ionizing radiation or by oxidation.
Inventors
- 👤 Donald E. Boynton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:28
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/28; C08F; C08F8/00; C08F8/50; C08F2810/00; C08F2810/10; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; C08J2423/00; C08J2423/02; C08J2423/10; C08J2423/12; Y; Y10; Y10S; Y10S260/00; Y10S260/43; Y10S522/00; Y10S522/911; Y10S522/912
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
143 words
A process for preparing an environmentally stable plastic composition by visbreaking a propylene polymer to controllably reduce its molecular weight, using an activated portion of said propylene polymer as a prodegradant, which process comprises: forming a prodegradant by activating a first portion of propylene polymer by exposure to ionizing radiation; incorporating said prodegradant into a second portion of propylene polymer, wherein said second portion is at least as large as said first portion; adding to the mixture of said first and second portions of said propylene polymer a stabilizing amount of an antioxidant; and visbreaking said mixture by shear mixing in an extruder while heating said mixture to an extrusion temperature between about 200° C. and 300° C. to controllably lower the molecular weight of said mixture and narrow the molecular weight distribution, while substantially retaining the stabilizing effect of said antioxidant stabilizer.
Claim 2
Dependent Claim
143 words
A process for preparing an environmentally stable plastic composition by visbreaking a propylene polymer to controllably reduce its molecular weight, using an activated portion of said propylene polymer as a prodegradant, which process comprises: forming a prodegradant by activating a first portion of propylene polymer by exposure to ionizing radiation; incorporating said prodegradant into a second portion of propylene polymer, wherein said second portion is at least as large as said first portion; adding to the mixture of said first and second portions of said propylene polymer a stabilizing amount of an antioxidant; and visbreaking said mixture by shear mixing in an extruder while heating said mixture to an extrusion temperature between about 200° C. and 300° C. to controllably lower the molecular weight of said mixture and narrow the molecular weight distribution, while substantially retaining the stabilizing effect of said antioxidant stabilizer.
Claim 3
Dependent Claim
131 words
A process for preparing an environmentally stable plastic composition by visbreaking a propylene polymer to controllably reduce its molecular weight, using an activated portion of said propylene polymer as a prodegradant, which process comprises: forming a prodegradant by activating a first portion of propylene polymer by exposure to ionizing radiation; incorporating said prodegradant into a second portion of propylene polymer, wherein said second portion is at least as large as said first portion and said second portion contains a stabilizing amount of at least one reactive antioxidant stabilizer; visbreaking said mixture by shear mixing in an extruder while heating said mixture to an extrusion temperature between about 200° C. and 300° C. to controllably lower the molecular weight of said mixture, while substantially retaining the stabilizing effect of said antioxidant stabilizer.
Claim 4
Dependent Claim
131 words
A process for preparing an environmentally stable plastic composition by visbreaking a propylene polymer to controllably reduce its molecular weight, using an activated portion of said propylene polymer as a prodegradant, which process comprises: forming a prodegradant by activating a first portion of propylene polymer by exposure to ionizing radiation; incorporating said prodegradant into a second portion of propylene polymer, wherein said second portion is at least as large as said first portion and said second portion contains a stabilizing amount of at least one reactive antioxidant stabilizer; visbreaking said mixture by shear mixing in an extruder while heating said mixture to an extrusion temperature between about 200° C. and 300° C. to controllably lower the molecular weight of said mixture, while substantially retaining the stabilizing effect of said antioxidant stabilizer.
Claim 5
Dependent Claim
15 words
The process of claims 1 or 2 wherein said ionizing radiation includes electron beam radiation.
Claim 6
Dependent Claim
14 words
The process of claims 1 or 2 wherein said ionizing radiation includes gamma-ray radiation.
Claim 7
Dependent Claim
18 words
The process of claims 1 or 2 wherein said ionizing radiation is between about 0.1 and 10.0 megarads.
Claim 8
Dependent Claim
18 words
The process of claims 1 or 2 wherein said ionizing radiation is between about 0.5 and 2.5 megarads.
Claim 9
Dependent Claim
16 words
The process of claims 1 or 2 wherein said reactive antioxidant stabilizer is a substituted phenol.
Claim 10
Dependent Claim
23 words
The process of claims 1 or 2 wherein said mixture is heated during extrusion with a holdup time of at least 30 seconds.
Claim 11
Dependent Claim
19 words
The process of claims 1 or 2 wherein said extrusion temperature is between about 225° C. and 275° C.
Claim 12
Dependent Claim
27 words
The process of claims 1 or 2 wherein said first portion constitutes from about 0.5% to 50% of the total weight of said first and second portions.
Claim 13
Dependent Claim
25 words
The process of claim 10 wherein said first portion constitutes from about 5% to 25% of the total weight of said first and second portions.
Claim 14
Dependent Claim
12 words
The process of claim 7 wherein said antioxidant stabilizer is 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl) benzene.
Claim 15
Dependent Claim
79 words
The process of claim 2, wherein said prodegradant is formed by exposing said first portion of said propylene polymer to ionizing radiation between about 0.5 and 2.5 megarads, said stabilizer is a substituted phenol, said first portion constitutes from about 5% to 25% of the total weight of said first and second portions and said mixture is heated during extrusion to a temperature between about 225° C. and 275° C. with a holdup time of at least 30 seconds.
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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) | 1984-08-03 | 1985-02-02 | 1985-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-03 | 1989-02-02 | 1989-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-03 | 1993-02-02 | 1993-08-04 | $7700.00 | Window Closed / Lapsed |