Patent US4160004A successfully refreshed from Google Patents.
US4160004A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of fibrous sheet material
Assignee: Karl Kroyer St Annes Ltd
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Filing: 1976-07-26
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Granted: 1979-07-03
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Expires: 1996-07-26
Abstract
Abstract A method for producing a self-sustaining sheet of essentially cellulosic fibrous material with improved strength wherein a dry-laid web is moistened and then consolidated by passage along a heated consolidating surface wherein the web is held against this surface by one side of a supporting band, against the other side of which at least two spaced apart pressure rolls exert a pressure acting through the supporting band against the web, which pressure is preferably between 150 and 500 pounds per linear inch. The supporting band thereby maintains the web against the heated consolidating roll between said pair of pressure nips.
Inventors
- 👤 Harold G. Curry
- 👤 Brian W. Attwood
- 👤 Derek G. W. White
- 👤 John M. Christensen
- 👤 Karl K. K. Kroyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:50
CPC Classifications
D; D21; D21F; D21F5/00; D21F5/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
310 words
A method of producing a self-sustaining sheet including essentially cellulosic fibrous material comprising: (a) dry laying a web of essentially cellulosic fibres upon a movable support surface, wherein the web includes a binder, (b) moistening said dry-laid web with water in an amount into subsequently bond the web to a consolidated sheet under subsequently applied pressure, (c) moving said moistened web with said movable support surface to a first pressure nip between a first pressure roll and a heated consolidating surface, with a supporting band located against the web on the side thereof opposite from the consolidating surface, wherein the consolidating surface together with the first pressure roll, the latter acting through the supporting band, exert on the moistened heated web therebetween uniformly across the width of the web a pressure of between 150 to 500 pounds per linear inch to consolidate the web, (d) maintaining the supporting band against the web after the web leaves the first pressure nip to continue to urge the web against the heated consolidating surface between the first pressure nip and a second pressure nip spaced from the first pressure nip to maintain, between the first and second pressure nips, a pressure exerting the web against the consolidating surface, (e) moving the web into the said second pressure nip, which is formed between the said heated consolidating surface and a second pressure roll with the supporting band against the web on the side thereof opposite from said heated consolidating surface, wherein the heated consolidating surface and the second pressure roll, the latter acting through the supporting band, exert on the moistened heated web therebetween uniformly across the width of the web a pressure of between 150 to 500 pounds per linear inch to further consolidate the web to strengthen it, and (f) removing the web, now a self-sustaining sheet, from the second pressure nip.
Claim 2
Independent Claim
310 words
A method of producing a self-sustaining sheet including essentially cellulosic fibrous material comprising: (a) dry laying a web of essentially cellulosic fibres upon a movable support surface, wherein the web includes a binder, (b) moistening said dry-laid web with water in an amount into subsequently bond the web to a consolidated sheet under subsequently applied pressure, (c) moving said moistened web with said movable support surface to a first pressure nip between a first pressure roll and a heated consolidating surface, with a supporting band located against the web on the side thereof opposite from the consolidating surface, wherein the consolidating surface together with the first pressure roll, the latter acting through the supporting band, exert on the moistened heated web therebetween uniformly across the width of the web a pressure of between 150 to 500 pounds per linear inch to consolidate the web, (d) maintaining the supporting band against the web after the web leaves the first pressure nip to continue to urge the web against the heated consolidating surface between the first pressure nip and a second pressure nip spaced from the first pressure nip to maintain, between the first and second pressure nips, a pressure exerting the web against the consolidating surface, (e) moving the web into the said second pressure nip, which is formed between the said heated consolidating surface and a second pressure roll with the supporting band against the web on the side thereof opposite from said heated consolidating surface, wherein the heated consolidating surface and the second pressure roll, the latter acting through the supporting band, exert on the moistened heated web therebetween uniformly across the width of the web a pressure of between 150 to 500 pounds per linear inch to further consolidate the web to strengthen it, and (f) removing the web, now a self-sustaining sheet, from the second pressure nip.
Claim 3
Dependent Claim
55 words
A method according to claim 1, wherein the supporting band utilized to maintain said moistened web in contact with said heated consolidating surface is the same as the support surface utilized to move the moistened web to said first pressure nip, said support surface moving with said web through said first and second pressure nips.
Claim 4
Dependent Claim
14 words
A method according to claim 2, wherein said support surface comprises a permeable band.
Claim 5
Dependent Claim
21 words
A method according to claim 1, wherein the amount of moisture of said moistened web is less than 50% by weight.
Claim 6
Dependent Claim
26 words
A method according to claim 4, wherein said web is pressed in said nips at a pressure of 200-250 p.l.i. and a temperature of 200°-250° F.
Claim 7
Dependent Claim
23 words
A method according to claim 2, wherein said pressure rolls have a temperature substantially less than the temperature of said heated consolidating surface.
Claim 8
Dependent Claim
26 words
A method according to claim 2, including the further step of passing said self-sustaining sheet through a further pressure nip comprising at least one further roll.
Claim 9
Dependent Claim
40 words
A method according to claim 7, including removing the supporting band from the web after the second pressure nip and wherein said further roll is urged against the surface of said self-sustaining sheet previously in contact with said supporting band.
Claim 10
Dependent Claim
15 words
A method according to claim 7, wherein said further pressure nip comprises two further rolls.
Claim 11
Dependent Claim
20 words
A method according to claim 7, wherein said further roll forms said further pressure nip with said heated consolidating surface.
Claim 12
Dependent Claim
12 words
A method according to claim 7, wherein said further roll is heated.
Claim 13
Dependent Claim
27 words
A method according to claim 7, wherein said further roll is heated to a temperature of 300°-500° F. and is applied with a pressure of 150-500 p.l.i.
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) | 1982-07-02 | 1983-01-01 | 1983-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-02 | 1987-01-01 | 1987-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-02 | 1991-01-01 | 1991-07-03 | $7700.00 | Window Closed / Lapsed |