US4076569A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for upgrading plywood panels
Assignee: VENEER TECHNOLOGY Ltd
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Filing: 1976-04-14
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Granted: 1978-02-28
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Expires: 1996-04-14
Abstract
Abstract A method and apparatus for applying a coating of thermoplastic resin to the surface of low grade plywood panels so as to form smooth surface suitable for use in concrete forms or the like is described. Polyamides or like resins are applied to the surface of a panel and the panel passed beneath an extruder or doctor blade provided with upwardly inclined surface that accumulates a puddle of resin on the upstream side of the extruder blade. The panel leaves the extruder with a coating of resin which fills knot holes and other surface defects. The coated panel is passed through an oven heating only the top side of the panel thereby allowing a bottom portion of the resin layer which is nearest the wood to solidify while a top portion remains liquid. The panel may then either be covered with a layer of paper and compressed between nip rollers or passed beneath a smoothing device, such as a reverse wiping roll or a doctor blade, to smooth the upper portion of the resin layer. Paper covered panels to be used in concrete forming may be saturated with an appropriate release agent.
Inventors
- 👤 Arnold Buchbinder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:47
CPC Classifications
E; E04; E04G; E04G9/00; E04G9/02; E04G9/05; B; B05; B05D; B05D7/00; B05D7/06; B28; B28B; B28B7/00; B28B7/36; B28B7/364; B05D1/00; B05D1/40; B05D1/42
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
130 words
A process for the upgrading the surface of a panel of cellulosic material having surface irregularities or defects which comprise the steps of: feeding such a panel along a horizontal path; applying a thermoplastic resin to the upper surface of said panel while maintaining said thermoplastic resin at a temperature above its melting point so that said resin remains liquid; passing said panel beneath a doctor blade so that said liquid resin is spread across said upper surface to fill holes, cracks and fissures in said upper surface and form a resin layer completely across such surface; maintaining the upper portion of the resin layer at a temperature sufficient to maintain such portion in a liquid, tacky condition while permitting the lower portion of the layer to cool and solidify;
Claim 2
Dependent Claim
130 words
A process for the upgrading the surface of a panel of cellulosic material having surface irregularities or defects which comprise the steps of: feeding such a panel along a horizontal path; applying a thermoplastic resin to the upper surface of said panel while maintaining said thermoplastic resin at a temperature above its melting point so that said resin remains liquid; passing said panel beneath a doctor blade so that said liquid resin is spread across said upper surface to fill holes, cracks and fissures in said upper surface and form a resin layer completely across such surface; maintaining the upper portion of the resin layer at a temperature sufficient to maintain such portion in a liquid, tacky condition while permitting the lower portion of the layer to cool and solidify;
Claim 3
Dependent Claim
17 words
forming a smooth upper surface on said upper portion; and thereafter causing said upper portion to solidify.
Claim 4
Dependent Claim
17 words
forming a smooth upper surface on said upper portion; and thereafter causing said upper portion to solidify.
Claim 5
Dependent Claim
90 words
The process of claim 1 wherein said resin comprises a mixture by weight of about 90 percent of a polyamide resinous material having a softening point between 105° and 115° C., a Brookfield viscosity of between 12 and 18 poises at 160° C. and about 10 percent of a reactive polyamide resin having a softening point at about 48° C. a viscosity of between 7 to 12 poises at 150° C. and an amine value of between 85 and 95, said mixture having a softening point of about 107° C.
Claim 6
Dependent Claim
23 words
The process of claim 1 wherein said resin is applied at a rate of 125-175 pounds per thousand square feet of panel surface.
Claim 7
Dependent Claim
77 words
The process of claim 1 wherein said doctor blade comprises a blade having a lower edge pressurably engaging said panel and a lower surface inclined at a small acute angle with the surface of said panel upwardly from said edge in the direction opposite to the directon of movement of said panel whereby a supply of liquid resin will be maintained between said panel and said lower surface to fill holes, cracks, and fissures in the panel.
Claim 8
Dependent Claim
14 words
The process of claim 4 wherein said blade is resiliently biased against said base.
Claim 9
Dependent Claim
14 words
The process of claim 4 wherein said acute angle is between 5° and 15°.
Claim 10
Dependent Claim
21 words
The process of claim 1 wherein said panels are fed at a speed of about 30 to 60 feet per minute.
Claim 11
Dependent Claim
49 words
The process of claim 1 wherein the step of forming a smooth upper surface comprises: applying a sheet of paper to the upper surface of said layer; and passing the panel and said sheet of paper beneath a nip roll to distribute and smooth said unsolidified resin upper portion.
Claim 12
Dependent Claim
15 words
The process of claim 8 which further comprises saturating said paper with a coating agent.
Claim 13
Dependent Claim
11 words
The process of claim 9 wherein said coating agent comprising paraffin.
Claim 14
Dependent Claim
15 words
The process of claim 9 wherein said coating agent comprising an oil based release coating.
Claim 15
Dependent Claim
11 words
The process of claim 9 wherein said paper comprises kraft paper.
Claim 16
Dependent Claim
13 words
The process of claim 9 wherein said paper comprises a resin impregnated paper.
Claim 17
Dependent Claim
38 words
The process of claim 1 wherein said step of forming a smooth upper surface comprises: while said resin upper portion is still liquid, passing said panel beneath a doctor blade to smooth the surface of said upper portion.
Claim 18
Dependent Claim
18 words
The process according to claim 14 which further comprises coating the smoothed surface portion with a coating agent.
Claim 19
Dependent Claim
42 words
The process of claim 1 wherein said step of forming a smooth upper surface comprises : while said upper portion of said resin layer is still liquid, passing said panel beneath a wiping roll to smooth the surface of said upper portion.
Claim 20
Dependent Claim
17 words
The process according to claim 16 which further comprises coating the smoothed surface with a coating agent.
Claim 21
Dependent Claim
131 words
A process for coating the surface of a panel of cellulosic material which comprise the steps of: feeding such a panel along a horizontal path; applying a thermoplastic resin to the upper surface of said panel while maintaining said thermoplastic resin at a temperature above its melting point so that said resin remains liquid; passing said panel beneath a doctor blade so that said liquid resin is spread across said upper surface and forms a resin layer completely across such surface; maintaining the upper portion of the resin layer at a temperature sufficient to maintain such portion in a liquid, tacky condition while permitting the lower portion of the layer to cool and solidify; forming a smooth upper surface on said upper portion; and thereafter causing said upper portion to solidify.
Claim 22
Dependent Claim
131 words
A process for coating the surface of a panel of cellulosic material which comprise the steps of: feeding such a panel along a horizontal path; applying a thermoplastic resin to the upper surface of said panel while maintaining said thermoplastic resin at a temperature above its melting point so that said resin remains liquid; passing said panel beneath a doctor blade so that said liquid resin is spread across said upper surface and forms a resin layer completely across such surface; maintaining the upper portion of the resin layer at a temperature sufficient to maintain such portion in a liquid, tacky condition while permitting the lower portion of the layer to cool and solidify; forming a smooth upper surface on said upper portion; and thereafter causing said upper portion to solidify.
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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) | 1981-02-27 | 1981-08-29 | 1982-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-27 | 1985-08-29 | 1986-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-27 | 1989-08-29 | 1990-02-28 | $7700.00 | Window Closed / Lapsed |