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US4519963A
Expired / Lapsed
US
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Electroconductive cross-linked polyolefin foam and method for manufacture thereof
Assignee: SANWA KAKO Co Ltd 7 KOAZA-SHIMONOHAMADAI OAZA-SHIMOTSUYA KUMIYAMA-CHO KUZE-GUN KYOTO-FU JAPAN
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Filing: 1983-05-17
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Granted: 1985-05-28
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Expires: 2003-05-17
Abstract
Abstract An electroconductive cross-linked polyolefin foam having electric resistance of not more than 100 MΩ and comprising uniform minute cells and proving useful for the production of IC cases, etc. is provided by a method which comprises kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of carbon particles, and suitable amounts of a foaming agent and a cross-linking agent and heating the resultant cross-linkable and foamable composition under atmospheric pressure thereby allowing the composition to be cross-linked and foamed without being abruptly foamed or expanded or by a method which comprises heating the aforementioned cross-linkable and foamable composition in a metal mold under pressure to a temperature at which the foaming agent is not substantially decomposed thereby cross-linking the composition and then heating the resultant cross-linked foamable composition under atmospheric pressure thereby allowing the composition to be foamed without being abruptly foamed or expanded. The aforementioned cross-linking may be effected by irradiation of the composition with an electron beam.
Inventors
- 👤 Iwao Yoshida
- 👤 Takeo Kasanami
- 👤 Shuji Miura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:43
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; B; B29; B29C; B29C44/00; C08K; C08K3/00; C08K3/02; C08K3/04; H; H01; H01B; H01B1/00; H01B1/20; H01B1/24; B29K; B29K2023/00; B29K2105/00; B29K2105/04; B29K2105/24; C08J2323/00; C08J2323/02; Y; Y10; Y10S; Y10S264/00; Y10S264/18; Y10S521/00; Y10S521/915
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
109 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises: kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and suitable amounts of a foaming agent and a cross-linking agent, and heating the resultant cross-linkable and foamable composition under atmospheric pressure and at a temperature not more than 200° C. so that the gradient of foaming speed is maintained at 10 or less, thereby allowing the composition to be cross-linked and foamed without being abruptly foamed or expanded, wherein the gradient of foaming speed is the change of the expansion ratio per one minute.
Claim 2
Independent Claim
109 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises: kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and suitable amounts of a foaming agent and a cross-linking agent, and heating the resultant cross-linkable and foamable composition under atmospheric pressure and at a temperature not more than 200° C. so that the gradient of foaming speed is maintained at 10 or less, thereby allowing the composition to be cross-linked and foamed without being abruptly foamed or expanded, wherein the gradient of foaming speed is the change of the expansion ratio per one minute.
Claim 3
Dependent Claim
41 words
The method according to claim 1, wherein said cross-linkable and foamable composition, prior to said heating under atmospheric pressure, is shaped to a desired shape under application of pressure and heat such that the foaming agent will not be substantially decomposed.
Claim 4
Dependent Claim
84 words
The method according to claim 1, wherein said cross-linking and foaming of the cross-linkable and foamable composition by said heating under atmospheric pressure is carried out in two separate steps, the first step for heating the composition to effect decomposition of 15 to 85% of the foaming agent in the composition and the second step for heating the composition at a temperature higher than the temperature involved in the first step to effect complete decomposition of the remaining unaltered foaming agent and cross-linking agent.
Claim 5
Dependent Claim
37 words
The method according to claim 1 or claim 3, wherein the foaming of the composition by the heating under atmospheric pressure is carried out so that the gradient of foaming speed will be not more than 1.
Claim 6
Dependent Claim
23 words
The method according to claim 4, wherein said gradient of foaming speed is adjusted by incorporation of a foaming aid to the composition.
Claim 7
Dependent Claim
19 words
The method according to claim 2, wherein the shaping temperature falls in the range of 115° to 155° C.
Claim 8
Dependent Claim
32 words
The method according to claim 1, wherein the heating temperature during the cross-linking and foaming step performed on the cross-linkable and foamable composition falls in the range of 150° to 200° C.
Claim 9
Dependent Claim
44 words
The method according to claim 3, wherein the heating temperature during the cross-linking and foaming step falls in the range of 145° to 170° C. in the first separate step and in the range of 160° to 200° C. in the second separate step.
Claim 10
Dependent Claim
39 words
The method according to claim 1 or claim 3, wherein the heating of the cross-linkable and foamable composition is carried out in a metal bath, an oil bath, or a salt bath or under a current of nitrogen gas.
Claim 11
Independent Claim
135 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises: kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and suitable amounts of a foaming agent and a cross-linking agent, heating the resultant cross-linkable and foamable composition in a metal mold held under pressure to a temperature at which the foaming agent is not substantially decomposed thereby cross-linking the composition, and heating the resultant foamable, cross-linked composition under atmospheric pressure and at a temperature not more than 200° C. so that the gradient of foaming speed is maintained at 10 or less, thereby allowing the composition to be foamed without being abruptly foamed or expanded, wherein the gradient of foaming is the change of the expansion ratio per one minute.
Claim 12
Independent Claim
135 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises: kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and suitable amounts of a foaming agent and a cross-linking agent, heating the resultant cross-linkable and foamable composition in a metal mold held under pressure to a temperature at which the foaming agent is not substantially decomposed thereby cross-linking the composition, and heating the resultant foamable, cross-linked composition under atmospheric pressure and at a temperature not more than 200° C. so that the gradient of foaming speed is maintained at 10 or less, thereby allowing the composition to be foamed without being abruptly foamed or expanded, wherein the gradient of foaming is the change of the expansion ratio per one minute.
Claim 13
Dependent Claim
78 words
The method according to claim 10, wherein said foaming of the cross-linked foamable composition by said heating under atmospheric pressure is carried out in two separate steps, the first step for heating the composition to effect decomposition of 15 to 85% of the foaming agent in the composition and the second step for heating the composition at a temperature higher than the temperature involved in the first step to effect complete decomposition of the remaining unaltered foaming agent.
Claim 14
Dependent Claim
37 words
The method according to claim 10 or claim 11, wherein the foaming of the composition by the heating under atmospheric pressure is carried out so that the gradient of foaming speed will be not more than 1.
Claim 15
Dependent Claim
23 words
The method according to claim 12, wherein said gradient of foaming speed is adjusted by incorporation of a foaming aid to the composition.
Claim 16
Dependent Claim
23 words
The method according to claim 10, wherein the heating temperature during the cross-linking step falls in the range of 130° to 160° C.
Claim 17
Dependent Claim
23 words
The method according to claim 10, wherein the heating temperature during the foaming step falls in the range of 150° to 200° C.
Claim 18
Dependent Claim
42 words
The method according to claim 11, wherein the heating temperature during the foaming step falls in the range of 145° to 170° C. in the first separate step and in the range of 160° to 200° C. in the second separate step.
Claim 19
Dependent Claim
37 words
The method according to claim 10 or claim 11, wherein the heating of the foamable composition is carried out in a metal bath, an oil bath, or a salt bath or under a current of nitrogen gas.
Claim 20
Independent Claim
116 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and a suitable amount of a foaming agent, irradiating the resultant foamable composition with an electron beam thereby cross-linking the composition, and heating the resultant cross-linked foamable composition under atmospheric pressure and at a temperature of not more than 200° C. so that the gradient foaming speed is maintained at 10 or less, thereby allowing the composition to be foamed without being abruptly foamed or expanded, wherein the gradient of foaming speed is the change of the expansion ratio per one minute.
Claim 21
Independent Claim
116 words
A method for the manufacture of an electroconductive cross-linked polyolefin foam, which comprises kneading 100 parts by weight of a polyolefin, 10 to 30 parts by weight of particles of a conductive carbon black, and a suitable amount of a foaming agent, irradiating the resultant foamable composition with an electron beam thereby cross-linking the composition, and heating the resultant cross-linked foamable composition under atmospheric pressure and at a temperature of not more than 200° C. so that the gradient foaming speed is maintained at 10 or less, thereby allowing the composition to be foamed without being abruptly foamed or expanded, wherein the gradient of foaming speed is the change of the expansion ratio per one minute.
Claim 22
Dependent Claim
78 words
The method according to claim 18, wherein said foaming of the cross-linked foamable composition by said heating under atmospheric pressure is carried out in two separate steps, the first step for heating the composition to effect decomposition of 15 to 85% of the foaming agent in the composition and the second step for heating the composition at a temperature higher than the temperature involved in the first step to effect complete decomposition of the remaining unaltered foaming agent.
Claim 23
Dependent Claim
37 words
The method according to claim 18 or claim 19, wherein the foaming of the composition by the heating under atmospheric pressure is carried out so that the gradient of foaming speed will be not more than 1.
Claim 24
Dependent Claim
23 words
The method according to claim 20, wherein said gradient of foaming speed is adjusted by incorporation of a foaming aid to the composition.
Claim 25
Dependent Claim
23 words
The method according to claim 18, wherein the heating temperature during the foaming step falls in the range of 150 to 200° C.
Claim 26
Dependent Claim
42 words
The method according to claim 19, wherein the heating temperature during the foaming step falls in the range of 145° to 170° C. in the first separate step and in the range of 160° to 200° C. in the second separate step.
Claim 27
Dependent Claim
37 words
The method according to claim 18 or claim 19, wherein the heating of the foamable composition is carried out in a metal bath, an oil bath, or a salt bath or under a current of nitrogen gas.
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) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |