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Patent US3974236A successfully refreshed from Google Patents.
US3974236A
Expired / Lapsed
US
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Process for producing modified polypropylene
Assignee: Mitsubishi Chemical Corp
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Filing: 1975-02-18
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Granted: 1976-08-10
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Expires: 1995-02-18
Abstract
Abstract Heteroblock copolymers of propylene and ethylene containing a relatively small quantity of an isotactic polypropylene segment, a copolymer segment of very low ethylene (polymerized) content, and another copolymer segment of high ethylene (polymerized) content, in which the quantities of the three types of segments are specific, and in which the isotactic polypropylene content is specific, which heteroblock copolymers are produced by three types of successive steps of polymerization with the monomer feeds in specific ratios of ethylene/propylene, the ratio being zero for the first step.
Inventors
- 👤 Michio Koga
- 👤 Hideo Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:12
CPC Classifications
C; C08; C08F; C08F297/00; C08F297/06; C08F297/08; C08F297/083
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
151 words
A process for producing a heteroblock copolymer of propylene and ethylene which comprises: First Stage: at least one step of catalytically polymerizing propylene to produce isotactic polypropylene and at least one step of catalytically polymerizing a mixture of ethylene and propylene to produce an ethylene/propylene copolymer, the ethylene content in the mixture being 0.2 to 3% by weight, the content of the isotactic polypropylene being up to 25% by weight of the heteroblock copolymer to be produced in the First Stage, the First Stage being initiated by polymerizing propylene and the both steps being carried out successively; Second Stage: further catalytically polymerizing a mixture of ethylene and propylene to produce another copolymer of ethylene and propylene, the content of ethylene in the mixture being at least 50% by weight, until the quantity of the copolymer has amounted to 5 to 20% by weight of the heteroblock copolymer to be finally produced.
Claim 2
Dependent Claim
151 words
A process for producing a heteroblock copolymer of propylene and ethylene which comprises: First Stage: at least one step of catalytically polymerizing propylene to produce isotactic polypropylene and at least one step of catalytically polymerizing a mixture of ethylene and propylene to produce an ethylene/propylene copolymer, the ethylene content in the mixture being 0.2 to 3% by weight, the content of the isotactic polypropylene being up to 25% by weight of the heteroblock copolymer to be produced in the First Stage, the First Stage being initiated by polymerizing propylene and the both steps being carried out successively; Second Stage: further catalytically polymerizing a mixture of ethylene and propylene to produce another copolymer of ethylene and propylene, the content of ethylene in the mixture being at least 50% by weight, until the quantity of the copolymer has amounted to 5 to 20% by weight of the heteroblock copolymer to be finally produced.
Claim 3
Dependent Claim
25 words
A process as claimed in claim 1 in which each of said steps in said First Stage is carried out from 1 to 10 times.
Claim 4
Dependent Claim
25 words
A process as claimed in claim 1 in which each of said steps in said First Stage is carried out from 1 to 5 times.
Claim 5
Dependent Claim
26 words
A process as claimed in claim 1 in which said ethylene content in said mixture in said First Stage is 0.2 to 2.5 percent by weight.
Claim 6
Dependent Claim
26 words
A process as claimed in claim 1 in which said ethylene content in said mixture in said First Stage is 1.5 to 2.5 percent by weight.
Claim 7
Dependent Claim
34 words
A process as claimed in claim 1 in which the content of the isotactic polypropylene segment in the heteroblock copolymer to be produced in the First Stage is 0.1 to 20 percent by weight.
Claim 8
Dependent Claim
34 words
A process as claimed in claim 1 in which the content of the isotactic polypropylene segment in the heteroblock copolymer to be produced in the First Stage is 1 to 16 percent by weight.
Claim 9
Dependent Claim
27 words
A process as claimed in claim 1 in which said content of ethylene in the mixture in said Second Stage is 60 to 90 percent by weight.
Claim 10
Dependent Claim
33 words
A process as claimed in claim 1 in which the quantity of said copolymer in said Second Stage is 5 to 15 percent by weight of the heteroblock copolymer to be finally produced.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |