Patent US4514255A successfully refreshed from Google Patents.
US4514255A
Expired / Lapsed
US
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Process for the manufacture of dried, resin-treated fiber furnish
Assignee: Hexion Inc
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Filing: 1983-08-19
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Granted: 1985-04-30
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Expires: 2003-08-19
Abstract
Abstract The problem of resin precure encountered in fiberboard, especially medium-density fiberboard, produced by blow-line blending is overcome by adding an alkaline material to the wood fibers prior to blow-line blending in order to raise the pH of the wood preferably into the range of 4 to 7, and optimally around 5.5. Only the fiber used to form the surface layers of the mat which is hot pressed to form the fiberboard need have the alkaline material added thereto; alternatively, especially in the core layer of the mat, the action of the alkaline material may be reversed by adding an acid catalyst. The fiberboards formed have a glossy, hard surface which reduces the need for sanding.
Inventors
- 👤 John W. Maxwell
- 👤 Brian Vyse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:35
CPC Classifications
C; C09; C09J; C09J161/00; C09J161/20; C09J161/22; C09J161/24; C08; C08K; C08K7/00; C08K7/02; C08L; C08L97/00; C08L97/02
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
A process for forming a dried, resin-treated fiber furnish from a naturally-acidic fiber comprising: adding to said fibers not more than about 1% of the dry weight of said fibers of an alkaline material thereby neutralizing at least part of the acid in said fibers, and raising the pH of said fibers into the range of about 4 to about 7; blow-line blending said fibers with a urea-formaldehyde resin; and drying said resin-blended fibers to produce a dried, resin-treated fiber furnish, said drying being effected at a temperature sufficiently low that curing of said resin does not occur during said drying.
Claim 2
Dependent Claim
101 words
A process for forming a dried, resin-treated fiber furnish from a naturally-acidic fiber comprising: adding to said fibers not more than about 1% of the dry weight of said fibers of an alkaline material thereby neutralizing at least part of the acid in said fibers, and raising the pH of said fibers into the range of about 4 to about 7; blow-line blending said fibers with a urea-formaldehyde resin; and drying said resin-blended fibers to produce a dried, resin-treated fiber furnish, said drying being effected at a temperature sufficiently low that curing of said resin does not occur during said drying.
Claim 3
Dependent Claim
30 words
A process according to claim 1 wherein said quantity of alkaline material is sufficient to raise the pH of said fibers to the range of about 5.0 to about 6.5.
Claim 4
Dependent Claim
24 words
A process according to claim 2 wherein said quantity of alkaline material is sufficient to raise the pH of said fibers to about 5.5.
Claim 5
Dependent Claim
12 words
A process according to claim 1 wherein said fibers comprise wood fibers.
Claim 6
Dependent Claim
13 words
A process according to claim 1 wherein said alkaline material is sodium carbonate.
Claim 7
Dependent Claim
27 words
A process according to claim 1 wherein said addition of said alkaline material is effected by immersing said fibers in a liquid solution of said alkaline material.
Claim 8
Dependent Claim
43 words
A process according to claim 4 wherein wood chips coated with an aqueous solution of said alkaline material are with treated with steam and thereafter subjected to mechanical attrition sufficient to cause said chips to disintegrate into fibers prior to said blow-line blending.
Claim 9
Dependent Claim
29 words
A process according to claim 7 wherein said alkaline material is added to said wood chips in the preheater of the attrition mill used to effect said mechanical attrition.
Claim 10
Dependent Claim
38 words
A process according to claim 7 wherein said mechanical attrition is effected using an attrition mill having at least one pair of rotating discs and wherein said alkaline material is introduced between said discs of said attrition mill.
Claim 11
Dependent Claim
17 words
A process according to claim 7 wherein wax is added to said chips during said mechanical attrition.
Claim 12
Dependent Claim
21 words
A process according to claim 1 wherein said resin has a formaldehyde:urea mole ratio of from about 1.0:1 to about 1.8:1.
Claim 13
Dependent Claim
34 words
A process according to claim 1 for producing fiberboard wherein a layer of said resin-treated furnish is formed into a mat of said furnish and said mat is hot pressed to form said fiberboard.
Claim 14
Dependent Claim
56 words
A process according to claim 12 wherein an acidic catalyst for accelerating the setting of said resin is added to at least part of said resin-treated furnish used to form said mat, said addition of said acid catalyst being effected at a temperature sufficiently low to prevent curing of said resin prior to said hot pressing.
Claim 15
Dependent Claim
22 words
A process according to claim 13 wherein said acidic catalyst is added to all said resin-treated furnish used to form said mat.
Claim 16
Dependent Claim
92 words
A process according to claim 13 wherein said resin-treated furnish is divided into first and second portions and said acidic catalyst is added to said second portion but not to said first portion, and wherein a base layer of said first portion is formed, a core layer of said second portion is spread on top of said base layer, and a top layer of said first portion is spread on top of said core layer, thereby producing a mat having an acid-catalyzed core sandwiched between two surface layers which are not acid-catalyzed.
Claim 17
Dependent Claim
30 words
A process according to claim 12 wherein said hot pressing is effected such that no part of the mat is exposed to a temperature in excess of about 170° C.
Claim 18
Dependent Claim
50 words
A process according to claim 12 wherein a first surface layer of said resin-treated fiber furnish is spread on said surface, a core layer of resin-treated furnish is spread on said first surface layer and a second surface layer of said resin-treated fiber furnish is spread on said core layer.
Claim 19
Dependent Claim
23 words
A process according to claim 17 wherein said core layer is formed from a furnish prepared by mechanically blending fiber with a resin.
Claim 20
Dependent Claim
32 words
A process according to claim 4 wherein said fibers are derived from any one or more of birch, chestnut, poplar, spruce, pine, fir, hemlock, beech, ash, kimba, gaboon, linder and eucalyptus trees.
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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) | 1988-04-29 | 1988-10-29 | 1989-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-29 | 1992-10-29 | 1993-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-29 | 1996-10-29 | 1997-04-30 | $7700.00 | Window Closed / Lapsed |