EP0351866A2
Expired / Lapsed
EP
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Thermal treatment of irradiated polypropylene
Assignee: Basell North America Inc
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Filing: 1989-07-21
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Granted: —
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Expires: 2009-07-21
Abstract
Abstract Disclosed is a method of treating a free-radical-containing, optionally room-temperature-aged, irradiated, normally solid high-molecular-weight, semi-crystalline propylene polymer material at about from 40°C to 110°C for at least about 10 minutes before being exposed to the higher temperatures that deactivate the residual free radicals therein. Treatment of the polymer at the intermediate temperature causes recombination, and better utilization, of free radicals with the production of more long-chain branching. A two-stage fluid bed process, with a first stage at the intermediate temperature for radical recombination and a second radical-deactivation stage at a higher temperature, is preferred.
Inventors
- 👤 Anthony J. Denicola, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 10:08
CPC Classifications
C; C08; C08J; C08J7/00; C08J7/12; C08J7/16; C08J7/18; C08F; C08F6/00; C08F6/02; C08F8/00; C08F8/50; C08J3/00; C08J3/28; Y; Y10; Y10S; Y10S522/00; Y10S522/915
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
93 words
A method of making high-molecular-weight, long-chain branched propylene polymer material from linear semi-crystalline normally solid propylene polymer material in an environment in which an active-oxygen concentration of less than about 15% by volume is maintained, which method includes the steps of irradiating said linear polymer material with high-energy ionizing radiation and thermally deactivating residual free radicals in the irradiated polymer material, said method comprising heating the irradiated polymer material at a temperature in the range of about from 40°C to 110°C for at least about 10 minutes prior to deactivating residual free radicals.
Claim 2
Independent Claim
93 words
A method of making high-molecular-weight, long-chain branched propylene polymer material from linear semi-crystalline normally solid propylene polymer material in an environment in which an active-oxygen concentration of less than about 15% by volume is maintained, which method includes the steps of irradiating said linear polymer material with high-energy ionizing radiation and thermally deactivating residual free radicals in the irradiated polymer material, said method comprising heating the irradiated polymer material at a temperature in the range of about from 40°C to 110°C for at least about 10 minutes prior to deactivating residual free radicals.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein said irradiated polymer material is heated at a temperature up to about 80°C for at least about 30 minutes, and the active-oxygen concentration maintained in said environment is 0.004% or less.
Claim 4
Dependent Claim
18 words
The method of claim 2 wherein said irradiated polymer material is heated for up to about 2 hours.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein said irradiated polymer material is heated by passage through a fluid bed assembly.
Claim 6
Dependent Claim
30 words
The method of claim 4 wherein said irradiated polymer material is held at approximately room temperature for up to about 2 hours before its entry into said fluid bed assembly.
Claim 7
Independent Claim
84 words
A method of treating irradiated propylene polymer material comprising, in an environment in which an active-oxygen concentration of less than about 15% by volume is maintained, heating a free-radical-containing irradiated semi-cyrstalline propylene polymer material in a first stage at a temperature T₁ in the range of about from 40°C to 110°C for at least about 10 minutes, and in a second stage at a temperature T₂ of at least about 120°C for a time sufficient to allow deactivation of substantially all residual free radicals.
Claim 8
Independent Claim
84 words
A method of treating irradiated propylene polymer material comprising, in an environment in which an active-oxygen concentration of less than about 15% by volume is maintained, heating a free-radical-containing irradiated semi-cyrstalline propylene polymer material in a first stage at a temperature T₁ in the range of about from 40°C to 110°C for at least about 10 minutes, and in a second stage at a temperature T₂ of at least about 120°C for a time sufficient to allow deactivation of substantially all residual free radicals.
Claim 9
Dependent Claim
68 words
The method of claim 6 wherein, in the first of said stages, said material is heated at a temperature T₁ up to about 80°C for about from 30 to 120 minutes; in the second of said stages, said material is heated at a temperature T₂ of at least about 130°C for at least about 20 minutes; and the active-oxygen concentration maintained in said environment is 0.004% or less.
Claim 10
Dependent Claim
17 words
The method of claim 7 wherein T₂ is below the melting point of said propylene polymer material.
Claim 11
Dependent Claim
33 words
The method of claim 8 wherein said irradiated polymer material is passed through a first fluid bed assembly in said first stage, and through a second fluid bed assembly in said second stage.
Claim 12
Dependent Claim
31 words
The method of claim 9 wherein said irradiated polymer material is held at approximately room temperature for up to about 2 hours before its entry into said first fluid bed assembly.
Claim 13
Dependent Claim
17 words
The method of claim 7 wherein T₂ is above the melting point of said propylene polymer material.
Claim 14
Dependent Claim
20 words
The method of claim 11 wherein, in said second stage, said propylene polymer material is extruded in the molten condition.
References Cited (Backward Citations)
No citation records indexed.
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