US4606953A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polypropylene coated steel pipe
Assignee: Nippon Steel Corp
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Filing: 1984-06-15
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Granted: 1986-08-19
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Expires: 2004-06-15
Abstract
Abstract A polypropylene coated steel pipe comprising a steel pipe, an adhesive layer coated on the external surface of the steel pipe, which has been subjected to a pretreatment, and a polypropylene layer coated on the adhesive layer. The outermost polypropylene layer comprises, as a main constituent, a crystalline ethylene-propylene block copolymer and the adhesive layer comprises a modified polyolefin adhesive.
Inventors
- 👤 Kazuyuki Suzuki
- 👤 Masami Ishida
- 👤 Fuyuhiko Ohtsuki
- 👤 Yoshihiro Inuizawa
- 👤 Saburo Hinenoya
- 👤 Mansei Tanaka
- 👤 Yoshio Shindou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:44
CPC Classifications
B; B05; B05D; B05D7/00; B05D7/50; B05D7/52; B05D7/54; B05D7/14; B05D7/148; C; C08; C08J; C08J5/00; C08J5/12; C08J5/124; C09; C09J; C09J5/00; C09J5/02; F; F16; F16L; F16L58/00; F16L58/02; F16L58/04; F16L58/10; B05D2350/00; B05D2350/20; B05D2507/00; C08J2323/00; C08J2323/02; C08J2323/16; C09J2400/00; C09J2400/10; C09J2400/16; C09J2400/166; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1355; Y10T428/1359; Y10T428/31504; Y10T428/31511; Y10T428/31529; Y10T428/31678; Y10T428/31692
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
92 words
A polypropylene coated steel pipe comprising a steel pipe, an adhesive layer coated on the external surface of the steel pipe which has been subjected to a pretreatment, and a polypropylene layer coated on the adhesive layer, the outermost polypropylene layer comprising, as a main constituent, a crystalline ethylene-propylene block copolymer having a brittleness temperature of 15° C. or less and the adhesive layer comprising a mixture of an unsaturated carboxylic acid modified crystalline polypropylene, an unmodified crystalline polypropylene and a polyolefin rubber having a brittleness temperature of -20° C. or less.
Claim 2
Dependent Claim
92 words
A polypropylene coated steel pipe comprising a steel pipe, an adhesive layer coated on the external surface of the steel pipe which has been subjected to a pretreatment, and a polypropylene layer coated on the adhesive layer, the outermost polypropylene layer comprising, as a main constituent, a crystalline ethylene-propylene block copolymer having a brittleness temperature of 15° C. or less and the adhesive layer comprising a mixture of an unsaturated carboxylic acid modified crystalline polypropylene, an unmodified crystalline polypropylene and a polyolefin rubber having a brittleness temperature of -20° C. or less.
Claim 3
Dependent Claim
32 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the polypropylene comprising, as a main constituent, a crystalline ethylene-propylene block copolymer has a brittleness temperature of 15° C. or less.
Claim 4
Dependent Claim
28 words
A polypropylene coated steel pipe as claimed in claim 1, the depth of penetration of the crystalline ethylene-propylene block copolymer at 120° C. is 0.3 mm or less.
Claim 5
Dependent Claim
27 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the external surface of the steel pipe is pretreated by being cleaned by a mechanical pretreatment.
Claim 6
Dependent Claim
18 words
A polypropylene coated steel pipe as claimed in claim 4, wherein the mechanical pretreatment is a blasting treatment.
Claim 7
Dependent Claim
47 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the external surface of the steel pipe is pretreated by being coated by an epoxy primer having a glass transition temperature of 80° C. or more after the external surface is cleaned by a mechanical pretreatment.
Claim 8
Dependent Claim
18 words
A polypropylene coated steel pipe as claimed in claim 6, wherein the mechanical pretreatment is a blasting treatment.
Claim 9
Dependent Claim
33 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the external surface of the steel pipe is pretreated by being cleaned by a mechanical pretreatment, followed by a chemical conversion treatment.
Claim 10
Dependent Claim
27 words
A polypropylene coated steel pipe as claimed in claim 8, wherein the mechanical pretreatment is a blasting treatment and the chemical conversion treatment is a chromate treatment.
Claim 11
Dependent Claim
52 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the external surface of the steel pipe is pretreated by being cleaned by a mechanical pretreatment, being treated by a chemical conversion treatment, and being coated thereon by an epoxy primer having a glass transition temperature of 80° C. or more.
Claim 12
Dependent Claim
27 words
A polypropylene coated steel pipe as claimed in claim 10, wherein the mechanical pretreatment is a blasting treatment and the chemical conversion treatment is a chromate treatment.
Claim 13
Dependent Claim
73 words
A polypropylene coated steel pipe as claimed in claim 1, wherein the outermost layer comprises: (A) 55% to 95% by weight of a crystalline ethylene-propylene block copolymer insoluble in p-xylene at ambient temperature; (B) 2% to 40% by weight of polyethylene having a density of 0.93 g/cm 3 or more insoluble in p-xylene at ambient temperature; and (C) 3% to 20% by weight of a polyolefin rubber soluble in p-xylene at ambient temperature.
Claim 14
Dependent Claim
37 words
A polypropylene coated steel pipe as claimed in claim 12, wherein the polyethylene is an ethylene homopolymer or a copolymer of 85% by weight or more of ethylene and 15% by weight or less of an alpha-olefin.
Claim 15
Dependent Claim
31 words
A polypropylene coated steel pipe as claimed in claim 13, wherein the alpha-olefin is at least one member selected from the group consisting of propylene, butene-1, pentene, hexene, heptene, and octene.
Claim 16
Dependent Claim
43 words
A polypropylene coated steel pipe as claimed in claim 12, wherein the polyolefin rubber is at least one member selected from the group consisting of ethylene-propylene copolymer, rubbers, ethylene-propylene-non-conjugated diene terpolymer rubbers, ethylene-propylene-butene-1 terpolymer rubbers, polyisobutylene rubbers, 1,2-polybutadiene rubbers, and ethylene-vinylacetate copolymer rubbers.
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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) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |