US4748209A
Expired / Lapsed
US
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Method for improving impulse destructive strength of electrical insulating materials
Assignee: Eneos Corp
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Filing: 1987-06-08
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Granted: 1988-05-31
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Expires: 2007-06-08
Abstract
Abstract The present invention provides a method for improving impulse destructive strength of an electrical insulating material which is characterized by employing, as the electrical insulating material, a random copolymer of a styrene series monomer and ethylene or a combination of ethylene and another ethylenic unsaturated monomer, or a composition in which the copolymer is blended with an ethylene series polymer, the copolymer being prepared by introducing, into a reaction system, the styrene series monomer selected from the group of styrene and single-ring substituted styrenes, ethylene or the combination of ethylene and the ethylenic unsaturated monomer and a polymerization initiator, the latter being introduced thereinto separately from at least the styrene series monomer, and subjecting these monomers to a high-pressure radical copolymerization under a polymerization pressure of 500 to 4,000 kg/cm2 at a polymerization temperature of 50 DEG to 400 DEG C., the aforesaid polymer or composition satisfying the following (a) and (b): (a) a content of the styrene series monomer in the copolymer or the composition being within the range of 0.01 to 1 mol %; and (b) a crystallinity of the copolymer or the composition being 30% or more in accordance with X-ray diffraction.
Inventors
- 👤 Yuichi Orikasa
- 👤 Shinji Kojima
- 👤 Takashi Inoue
- 👤 Kaoru Yamamoto
- 👤 Atsushi Sato
- 👤 Shigenobu Kawakami
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:54
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; C; C08; C08F; C08F210/00; C08F210/02; Y; Y10; Y10S; Y10S526/00; Y10S526/913
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
190 words
A method for improving impulse destructive strength of an electrical insulating material which is characterized by employing, as said electrical insulating material, a random copolymer of a styrene series monomer and ethylene or a combination of ethylene and another ethylenically unsaturated monomer, or a composition in which said copolymer is blended with a polymer of ethylene, said copolymer being prepared by introducing, into a reaction system, said styrene series monomer selected from the group of styrene and single-ring substituted styrenes, ethylene or said combination of ethylene and said ethylenically unsaturated monomer and a polymerization initiator, the initiator being introduced thereinto separately from at least said styrene series monomer, and subjecting these monomers to a high-pressure radical copolymerization under a polymerization pressure of 500 to 4,000 kg/cm 2 at a polymerization temperature of 50° to 400° C., said polymer or said composition satisfying the following (a) and (b): (a) a content of said styrene series monomer in said copolymer or said composition being within the range of 0.01 to 1 mol %; and (b) a crystallinity of said copolymer or said composition being 30% or more in accordance with X-ray diffraction.
Claim 2
Independent Claim
190 words
A method for improving impulse destructive strength of an electrical insulating material which is characterized by employing, as said electrical insulating material, a random copolymer of a styrene series monomer and ethylene or a combination of ethylene and another ethylenically unsaturated monomer, or a composition in which said copolymer is blended with a polymer of ethylene, said copolymer being prepared by introducing, into a reaction system, said styrene series monomer selected from the group of styrene and single-ring substituted styrenes, ethylene or said combination of ethylene and said ethylenically unsaturated monomer and a polymerization initiator, the initiator being introduced thereinto separately from at least said styrene series monomer, and subjecting these monomers to a high-pressure radical copolymerization under a polymerization pressure of 500 to 4,000 kg/cm 2 at a polymerization temperature of 50° to 400° C., said polymer or said composition satisfying the following (a) and (b): (a) a content of said styrene series monomer in said copolymer or said composition being within the range of 0.01 to 1 mol %; and (b) a crystallinity of said copolymer or said composition being 30% or more in accordance with X-ray diffraction.
Claim 3
Dependent Claim
28 words
A method according to claim 1 wherein said styrene series monomer is previously dispersed into ethylene sufficiently and the resultant dispersion is then introduced into said reaction system.
Claim 4
Dependent Claim
28 words
A method according to claim 1 wherein said single-ring substituted styrene is at least one member selected from the group consisting of methylstyrene, dimethylstyrene, ethylstyrene and vinylbenzoic acid.
Claim 5
Dependent Claim
27 words
A method according to claim 1 wherein the content of said ethylenically unsaturated monomer in said copolymer is within the range of 0 to 3 mol %.
Claim 6
Dependent Claim
26 words
A method according to claim 1 wherein the melt index of said copolymer or said composition is within the range of 0.1 to 20 g/10 minutes.
Claim 7
Dependent Claim
39 words
A method according to claim 5 wherein said polymerization pressure is 1,000 to 3,500 kg/cm 2 , said polymerization temperature is 100° to 350° C. and said content of said styrene series monomer is 0.02 to 0.7 mol %.
Claim 8
Dependent Claim
38 words
A method according to claim 6 wherein the content of said ethylenically unsaturated monomer in said copolymer is within the range of 0 to 3 mol % and said styrene series monomer is styrene or alpha methyl styrene.
Claim 9
Dependent Claim
39 words
A method according to claim 1 wherein said polymerization pressure is 1,000 to 3,500 kg/cm 2 , said polymerization temperature is 100° to 350° C. and said content of said styrene series monomer is 0.02 to 0.7 mol %.
Claim 10
Dependent Claim
38 words
A method according to claim 8 wherein the content of said ethylenically unsaturated monomer in said copolymer is within the range of 0 to 3 mol % and said styrene series monomer is styrene or alpha methyl styrene.
Claim 11
Dependent Claim
25 words
A method according to claim 9 wherein the content of said ethylenically unsaturated monomer is 0 mol % and said styrene series monomer is styrene.
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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) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |