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US3645666A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for uniforming the color of wood and wood articles

Assignee: US PLYWOOD Corp A CORP OF
•
Filing: 1969-12-11
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Granted: 1972-02-29
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Expires: 1989-12-11
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Abstract

Abstract A method for uniformly bleaching the color of wood substrates which is characterized by preheating the substrates to a temperature of between about 140* and 200* F. applying a bleaching solution of hydrogen peroxide with, or without, an alkali metal silicate to at least the surfaces of the substrates, exposing the covered surfaces to vapors of anhydrous ammonia and drying. The apparatus for carrying out the method has a conveyor arranged for presenting the substrates or finished articles to a preheating station, preheating means such as a quartz tube or a convection oven, bleach-applying means, ammonia applying means and finally drying means. With this invention, after drying of the wood panel or assembled article, the surface thereof is free of residues which usually are left after other bleaching methods. No washing or neutralizing step is necessary with the claimed method.

Inventors

  • 👤 Carroll F Bailey
  • 👤 W Richard Oetgen

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 12:20
CPC Classifications
B; B27; B27K; B27K5/00; B27K5/02; B27K3/00; B27K3/02; B27K3/0207; B27K5/001

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 17 words
The method according to claim 1 wherein said solution includes hydrogen peroxide and an alkali metal silicate.
Claim 2
Dependent Claim 23 words
The method according to claim 1, wherein there is applied to said substrata over 6.0 g. of ammonia per sq. ft. of substrate.
Claim 3
Dependent Claim 18 words
The method according to claim 1, wherein said substrate is exposed to ammonia for at least 5 seconds.
Claim 4
Dependent Claim 37 words
The method according to claim 3, wherein said solution has a pH ranging from 7 to 8, and said substrate is heated to approximately 180* F. and said ammonia is heated in the range of 200*-210* F.
Claim 5
Dependent Claim 23 words
The method of claim 3, wherein the amount of solution applied to said substrate is from 8 to 10 cc. per sq. ft.
Claim 6
Dependent Claim 21 words
The method according to claim 3, wherein said heating is carried out for a period of about 30 to 60 seconds.
Claim 7
Dependent Claim 72 words
The method of claim 3 wherein the alkali metal silicate is prepared by mixing 3.22 to 1 wt. ratio of SiO2 to Na2O with a specific gravity of 40 Baume, diluting 150 units of this solution with 150 units of water, subsequently adding gradually to 2,000 units of 35 percent hydrogen peroxide at room temperature, and then placing in an ice and acetone bath to bring to 30*-40* F. to minimize gelling.
Claim 8
Dependent Claim 14 words
The method according to claim 3, wherein said alkali metal silicate is sodium silicate.
Claim 9
Dependent Claim 16 words
The method of claim 7 wherein the solution has a pH in the range of 7-8.
Claim 10
Dependent Claim 26 words
The method of claim 9 wherein the pH is adjusted to approximately 7.8, and said ammonia is at a temperature in the range of 200*-210* F.
Claim 11
Dependent Claim 31 words
The method according to claim 1 wherein the concentration of said hydrogen peroxide is approximately 35 percent and said ammonia is heated to a temperature in the range of 200*-210* F.

References Cited (Backward Citations)

US2107297A Cited
US2185632A Cited
US2203589A Cited
US2194358A Cited
US2191431A Cited
US3144297A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-02-28 1975-08-30 1976-02-29 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-02-28 1979-08-30 1980-02-29 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-02-28 1983-08-30 1984-02-29 $7700.00 Window Closed / Lapsed

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