US5200439A
Expired / Lapsed
US
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Method for increasing intrinsic viscosity of syndiotactic polypropylene
Assignee: Mitsui Chemicals Inc
•
Filing: 1991-04-02
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Granted: 1993-04-06
•
Expires: 2011-04-02
Abstract
Abstract A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure is disclosed which comprises the step of irradiating the syndiotactic polypropylene with radiation in the absence of oxygen. After the irradiation, the polypropylene is preferably heated. Furthermore, the polypropylene having the substantially syndiotactic structure which remains in a melting state can be irradiated with radiation. The polypropylene having the substantially syndiotactic structure is preferably polypropylene in which any diffraction line is not substantially observed in a spacing of about 7.1 Å by X-ray diffraction.
Inventors
- 👤 Tadashi Asanuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:23
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/28; C08F; C08F255/00; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; Y; Y10; Y10S; Y10S526/00; Y10S526/943
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
49 words
A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure which comprises irradiating syndiotactic propylene having an intrinsic viscosity of from 0.1 to 5 with radiation in the absence of oxygen, and then heating the irradiated syndiotactic polypropylene until radicals formed by the irradiation disappear.
Claim 2
Independent Claim
49 words
A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure which comprises irradiating syndiotactic propylene having an intrinsic viscosity of from 0.1 to 5 with radiation in the absence of oxygen, and then heating the irradiated syndiotactic polypropylene until radicals formed by the irradiation disappear.
Claim 3
Dependent Claim
23 words
The method according to claim 1 wherein the polypropylene having the substantially syndiotactic structure has a syndiotactic pentad fraction of 0.6 or more.
Claim 4
Dependent Claim
69 words
The method according to claim 1 wherein the polypropylene having the substantially syndiotactic structure is a copolymer of propylene and an olefin other than propylene in which in its 13 C-NMR absorption spectrum measured in a 1,2,4-trichlorobenzene solution on the basis of tetramethylsilane, a peak intensity observed at about 20.2 ppm is 0.3 or more of a peak intensity attributed to all the methyl groups of the propylene units.
Claim 5
Dependent Claim
19 words
The method according to claim 1 wherein the syndiotactic polypropylene has an intrinsic viscosity of from 0.1 to 2.0.
Claim 6
Dependent Claim
18 words
The method according to claim 1 wherein the dose of the radiation is from 0.1 to 50 Mrad.
Claim 7
Dependent Claim
18 words
The method according to claim 1 wherein the dose of the radiation is from 1 to 10 Mrad.
Claim 8
Dependent Claim
20 words
The method according to claim 1 wherein the irradiation is carried out at a temperature of 100° C. or less.
Claim 9
Dependent Claim
38 words
The method according to claim 1 wherein after the irradiation the polypropylene is heated at a temperature which is higher than the temperature at the time of the irradiation but lower than the melting point of the polypropylene.
Claim 10
Dependent Claim
20 words
The method according to claim 8 wherein the heating temperature is in the range of from 80° to 140° C.
Claim 11
Dependent Claim
36 words
The method according to claim 1 wherein the polypropylene having the substantially syndiotactic structure is a polypropylene in which a diffraction line is not substantially observed in a spacing of about 7.1 Å by X-ray diffraction.
Claim 12
Dependent Claim
20 words
The method according to claim 10 wherein the irradiation is carried out at 30° C. or less, followed by heating.
Claim 13
Independent Claim
41 words
A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure which comprises melting syndiotactic polypropylene having an intrinsic viscosity of from 0.1 to 5, and then irradiating the melted propylene with radiation while in a liquid state.
Claim 14
Independent Claim
41 words
A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure which comprises melting syndiotactic polypropylene having an intrinsic viscosity of from 0.1 to 5, and then irradiating the melted propylene with radiation while in a liquid state.
Claim 15
Dependent Claim
21 words
The method according to claim 12 wherein the melted polypropylene is irradiated at a temperature of form 60° to 300° C.
Claim 16
Dependent Claim
23 words
The method according to claim 12 wherein the polypropylene having the substantially syndiotactic structure has a syndiotactic pentad fraction of 0.6 or more.
Claim 17
Dependent Claim
69 words
The method according to claim 12 wherein the polypropylene having the substantially syndiotactic structure is a copolymer of propylene and an olefin other than propylene in which in the 13 C-NMR absorption spectrum, measured in a 1,2,4-trichlorobenzene solution on the basis of tetramethylsilane, a peak intensity observed at about 20.2 ppm is 0.3 or more of a peak intensity attributed to all the methyl groups of the propylene units.
Claim 18
Dependent Claim
19 words
The method according to claim 12 wherein the syndiotactic polypropylene has an intrinsic viscosity of from 0.1 to 2.0.
Claim 19
Dependent Claim
18 words
The method according to claim 12 wherein the dose of the radiation is from 0.1 to 50 Mrad.
Claim 20
Dependent Claim
18 words
The method according to claim 12 wherein the dose of the radiation is from 1 to 10 Mrad.
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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) | 1996-04-05 | 1996-10-05 | 1997-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-05 | 2000-10-05 | 2001-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-05 | 2004-10-05 | 2005-04-06 | $7700.00 | Window Closed / Lapsed |