US4252171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Withstand-voltage tire
Assignee: Bridgestone Corp
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Filing: 1978-12-13
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Granted: 1981-02-24
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Expires: 1998-12-13
Abstract
Abstract A tire having excellent withstand-voltage property, wear resistance and resistance against heat build-up is disclosed. The tire has a tread, at least the contact area of the tread with road surface being made of a rubber composition containing a specifically limited softening agent and a specifically limited carbon black.
Inventors
- 👤 Isamu Imai
- 👤 Kazuo Koyama
- 👤 Mitsuaki Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:48
CPC Classifications
B; B60; B60C; B60C1/00; B60C1/0016; B60C19/00; B60C19/08; Y; Y10; Y10T; Y10T152/00; Y10T152/10; Y10T152/10495; Y10T152/10765; Y10T152/1081
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
229 words
A withstand-voltage tire having a cap-base structure tread comprising a thread cap and a tread base, said tread cap having a thickness of at least 1/2 of the thickness of the tread or extending to a position below a line connecting the groove bottoms of the tread patterns, and said tread cap being made of a rubber composition consisting of 100 parts by weight of a rubber selected from the group consisting of natural rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, polybutadiene rubber and blends thereof, 1-10 parts by weight of at least one softening agent selected from the group consisting of natural rosin, glycerine ester of rosin, polymerized rosin and a phenolic resin, and 30-90 parts by weight of carbon black having an iodine adsorbability of from more than 83 mg/g to 150 mg/g and a dibutyl phthalate absorbability of 80-120 ml/100 g, and said tread base being made of a rubber composition consisting of 100 parts by weight of a rubber selected from the group consisting of natural rubber, polyisoprene rubber, polybutadiene rubber and blends thereof, 0-3 parts by weight of at least one softening agent selected from the group consisting of natural rosin, glycerine ester of rosin, polymerized rosin and a phenolic resin, and 20-50 parts by weight of carbon black having an iodine adsorbability of 40-83 mg/g and a dibutyl phthalate absorbability of 80-120 ml/100 g.
Claim 2
Dependent Claim
229 words
A withstand-voltage tire having a cap-base structure tread comprising a thread cap and a tread base, said tread cap having a thickness of at least 1/2 of the thickness of the tread or extending to a position below a line connecting the groove bottoms of the tread patterns, and said tread cap being made of a rubber composition consisting of 100 parts by weight of a rubber selected from the group consisting of natural rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, polybutadiene rubber and blends thereof, 1-10 parts by weight of at least one softening agent selected from the group consisting of natural rosin, glycerine ester of rosin, polymerized rosin and a phenolic resin, and 30-90 parts by weight of carbon black having an iodine adsorbability of from more than 83 mg/g to 150 mg/g and a dibutyl phthalate absorbability of 80-120 ml/100 g, and said tread base being made of a rubber composition consisting of 100 parts by weight of a rubber selected from the group consisting of natural rubber, polyisoprene rubber, polybutadiene rubber and blends thereof, 0-3 parts by weight of at least one softening agent selected from the group consisting of natural rosin, glycerine ester of rosin, polymerized rosin and a phenolic resin, and 20-50 parts by weight of carbon black having an iodine adsorbability of 40-83 mg/g and a dibutyl phthalate absorbability of 80-120 ml/100 g.
Claim 3
Dependent Claim
27 words
A withstand-voltage tire according to claim 1, wherein the amount of the at least one softening agent used in the tread cap is 1-5 parts by weight.
Claim 4
Dependent Claim
32 words
A withstand-voltage tire according to claim 1, wherein said carbon black used in the tread cap has an iodine adsorbability of 110-150 mg/g and a dibutyl phthalate absorbability of 100-120 ml/100 g.
Claim 5
Dependent Claim
24 words
A withstand-voltage tire according to claim 1, wherein the amount of said carbon black used in the tread cap is 40-50 parts by weight.
Claim 6
Dependent Claim
32 words
A withstand-voltage tire according to claim 1, wherein said carbon black used in the tread base has an iodine adsorbability of 30-50 mg/g and a dibutyl phthalate absorbability of 100-120 ml/100 g.
Claim 7
Dependent Claim
24 words
A withstand-voltage tire according to claim 1, wherein the amount of said carbon black used in the tread base is 30-40 parts by weight.
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) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |