US5164251A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paper machine felts
Assignee: Albany International Corp
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Filing: 1990-11-28
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Granted: 1992-11-17
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Expires: 2010-11-28
Abstract
Abstract The present invention relates to a felt for use in papermaking machines showing enhanced resistance to degradation in the presence of peroxide which felt comprises a woven base and a sheet contracting layer attached thereto characterized in that at least one of said layer and said woven base comprises fibers of polyamide 12, 12 found by extrusion of a melt of polyamide 12, 12 having intrinsic viscosity of not less than 0.65 dl/gram.
Inventors
- 👤 Robert B. Davis
- 👤 Charles E. Kramer
- 👤 Sandra K. Barlow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:36
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/58; D01F6/60; D21; D21F; D21F7/00; D21F7/08; D21F7/083; Y; Y10; Y10S; Y10S162/00; Y10S162/90; Y10T; Y10T442/00; Y10T442/30; Y10T442/3707; Y10T442/3724
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
56 words
A felt for use in papermaking machines comprising a woven base and at least one batt fibre needled thereto characterised in that at least one of said batt fibre and said woven base comprises fibres of polyamide 12,12 formed by extrusion of a melt of polyamide 12,12 having intrinsic viscosity of not less than 0.65 dl/gram.
Claim 2
Dependent Claim
56 words
A felt for use in papermaking machines comprising a woven base and at least one batt fibre needled thereto characterised in that at least one of said batt fibre and said woven base comprises fibres of polyamide 12,12 formed by extrusion of a melt of polyamide 12,12 having intrinsic viscosity of not less than 0.65 dl/gram.
Claim 3
Dependent Claim
24 words
A felt as claimed in claim 1 characterised in that the melt of polyamide 12,12 contains 0.2 to 1.0% by weight of an antioxidant.
Claim 4
Dependent Claim
25 words
A felt as claimed in claim 2 characterised in that the melt of the polyamide 12,12 contained 0.4 to 0.6% by weight of an antioxidant.
Claim 5
Dependent Claim
40 words
A felt as claimed in claim 3 characterised in that the antioxidant is selected from one or more of alphatocopherol and related structures, condensation products of diphenylamine and acetone, and of diphenylamine and a compatible phenolic stabliser with amide functionality.
Claim 6
Dependent Claim
18 words
A felt as claimed in claim 2 wherein the addition of antioxidant is added at or before extrusion.
Claim 7
Dependent Claim
40 words
A felt as claimed in claim 1 characterised in that the felt comprises a woven base including monofilaments of polyamide 12,12 having an intrinsic viscosity of not less than 0.60 dl/gram. in either the warp direction or the shute direction.
Claim 8
Dependent Claim
24 words
A felt as claimed in claim 1 wherein filaments or monofilaments of polyamide 12,12 are drawn and subject to a controlled relaxation after drawing.
Claim 9
Dependent Claim
21 words
A felt as claimed in claim 7 wherein the relaxation step comprises a relaxation within the range of 5% to 15%.
References Cited (Backward Citations)
US4874660A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-17 | 1996-05-18 | 1996-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-17 | 2000-05-18 | 2000-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-17 | 2004-05-18 | 2004-11-17 | $7700.00 | Window Closed / Lapsed |