Patent US4258119A successfully refreshed from Google Patents.
US4874660A
Expired / Lapsed
US
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Paper machine felts
Assignee: Albany Research UK Ltd
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Filing: 1988-04-14
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Granted: 1989-10-17
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Expires: 2008-04-14
Abstract
Abstract The invention relates to an improved felt for a paper making machine having a batt formed from polyamide-12 needled to a woven base. The polyamide 12 batt may contain an antioxidant. The felts in accordance with the invention show much improved longevity and resistance to "flattening" in service.
Inventors
- 👤 Robert B. Davis
- 👤 Charles E. Kramer
- 👤 Sandra K. Barlow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 01:11
CPC Classifications
D; 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: 11
Claim 1
Independent Claim
52 words
A felt for use in a paper making machine comprising a woven base and at least one layer of batt fibre needled thereto, characterised in that said batt fibre comprises fibres of polyamide-12 formed by the extrusion of a melt of polyamide-12 having an intrinsic viscosity of not less than 0.6 dl/gm.
Claim 2
Dependent Claim
52 words
A felt for use in a paper making machine comprising a woven base and at least one layer of batt fibre needled thereto, characterised in that said batt fibre comprises fibres of polyamide-12 formed by the extrusion of a melt of polyamide-12 having an intrinsic viscosity of not less than 0.6 dl/gm.
Claim 3
Dependent Claim
20 words
A felt as claimed in claim 1 characterised in that said melt contains 0.2 to 1.0% by weight of antioxidant.
Claim 4
Dependent Claim
18 words
A felt as claimed in claim 2 characterized in that the amount of antioxidant is 0.4 to 0.6%.
Claim 5
Dependent Claim
34 words
A felt as claimed in claim 1 characterised in that said melt contains an antioxidant selected from the group consisting of alpha-tocopherol, condensation products of diphenylamine and acetone and multifunctional amide containing phenolic antioxidants.
Claim 6
Dependent Claim
20 words
A felt as claimed in claim 4 characterized in that said melt contains 0.2 to 1.0% by weight of antioxidant.
Claim 7
Dependent Claim
18 words
A felt as claimed in claim 5 characterized in that the amount of antioxidant is 0.4 to 0.6%.
Claim 8
Dependent Claim
17 words
A felt as claimed in claim 6 characterized in that said intrinsic viscosity is greater than 0.7.
Claim 9
Dependent Claim
27 words
A felt as claimed in claim 1 characterised in that at least one of the shute and warp filaments of the woven base is formed of polyamide-12.
Claim 10
Dependent Claim
17 words
A felt as claimed in claim 1 characterized in that said intrinsic viscoisity is greater than 0.7.
Claim 11
Dependent Claim
18 words
A felt as claimed in claim 9 characterized in that the amount of antioxidant is 0.4 to 0.6%.
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) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |