USRE31354E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for coating metal tubes and use of the coated tubes
Assignee: Hoechst AG
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Filing: 1982-09-16
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Granted: 1983-08-23
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Expires: 2002-09-16
Abstract
Abstract A process for the coating of metal tubes by the application of polyethylene to the preheated tubes, a polyethylene with a melt index of over 1 g/10 minutes being applied first to the pre-heated metal tube and a polyethylene with a low melt index being applied thereupon, the process comprising a first step of applying a polyethylene with a melt index of 1.2 to 70 g/10 minutes (190° C./2.16 kg) to the metal tube which has been pre-heated to a temperature of at least 200° C., a second step in which the coating is cooled to a temperature of about 110° to 170° C. and a third step of applying a self-supporting film of polyethylene with a melt index of 0.1 to 7 g/10 minutes at this temperature so that the total coating has a minimum layer thickness of 1.5 to 4 mm and a coated article coated according to said process.
Inventors
- 👤 Gunter Eckner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:26
CPC Classifications
B; B05; B05D; B05D7/00; B05D7/14; B05D7/146; B05D1/00; B05D1/002; B05D2507/00; B05D2507/01
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
A process for coating preheated metal tubes with polyethylene in at least two steps, wherein a metal tube which has been preheated to a temperature of at least 200° C. and at most 250° C. is coated in a first step with polyethylene having a melt index between 1.2 and 70 g/10 min. (190° C./2.16 kg), the coating is cooled in a second step to a temperature between 110° and 170° C., and subsequently in a third step a self-supporting film of polyethylene having a melt index between 0.1 and 7 g/10 min is applied by winding round the tube at a temperature between 110° and 170° C. so that the total coating has a minimum thickness of 1.5 to 4 mm.
Claim 2
Dependent Claim
122 words
A process for coating preheated metal tubes with polyethylene in at least two steps, wherein a metal tube which has been preheated to a temperature of at least 200° C. and at most 250° C. is coated in a first step with polyethylene having a melt index between 1.2 and 70 g/10 min. (190° C./2.16 kg), the coating is cooled in a second step to a temperature between 110° and 170° C., and subsequently in a third step a self-supporting film of polyethylene having a melt index between 0.1 and 7 g/10 min is applied by winding round the tube at a temperature between 110° and 170° C. so that the total coating has a minimum thickness of 1.5 to 4 mm.
Claim 3
Dependent Claim
29 words
A process as claimed in claim 1, wherein a polyethylene having a melt index between 15 and 70 g/10 min (190° C./2.16 kg) is applied in the first step.
Claim 4
Dependent Claim
86 words
A process as claimed in claim 1, wherein in the first step a polyethylene powder having a melt index between about 1.2 and 1.7 g/10 min (190° C./2.16 kg) and coming directly from an extruder is applied to the metal tube which has been preheated to a temperature of at least 300° C. in the case of powder-coating and wherein in a third step a self-supporting photo-stabilized light-colored film of polyethylene having a melt index between 0.4 and 1.1 g/10 min is applied as a coating.
Claim 5
Dependent Claim
24 words
A process as claimed in claim 1, wherein in the second step the coating is cooled to a temperature between 110° and 150° C.
Claim 6
Dependent Claim
34 words
A process as claimed in claim 1, wherein in the third step the polyethylene with the lower melt index between 0.1 and 1.2 g/10 min is applied in the form of a polyethylene tape.
Claim 7
Dependent Claim
17 words
A process as claimed in claim 5, wherein the polyethylene tape is applied to a rotating tube.
Claim 8
Dependent Claim
29 words
A process as claimed in claim 1, wherein the polyethylene coating is applied in the form of a white polyethylene tape having a thickness between 100 and 200 μm.
Claim 9
Dependent Claim
39 words
A process as claimed in claim 1, wherein in a first step the polyethylene is applied in admixture with a vinyl acetate homo- or copolymer, the proportion of which being between 5 and 10% by weight, referred to polyethylene.
Claim 10
Dependent Claim
22 words
A coated article in the form of a metal tube having been coated according to the process as claimed in claim 1.
Claim 11
Dependent Claim
19 words
A coated article as claimed in claim 9 in the form of a pipeline for the transport of petroleum.
Claim 12
Dependent Claim
78 words
A process as claimed in claim 1, wherein in the first step a tape of polyethylene having a melt index of at most 1.7 g/10 min and coming directly from an extruder is applied to the metal tube which has been preheated to a temperature of at most 250° C. and wherein in a third step a self-supporting photo-stabilized light-colored film of polyethylene having a melt index between 0.4 and 1.1 g/10 min is applied as a coating.
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) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |