US3874908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composition and method for maintaining a constant concentration of agents and amount of solvent in a wood treating process
Assignee: Dow Chemical Co
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Filing: 1972-07-31
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Granted: 1975-04-01
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Expires: 1992-07-31
Abstract
Abstract In a wood treating process wherein wood is impregnated with a halogenated solvent solution containing a wood preservative and an antiblooming additive and excess solvent is vaporized from the impregnated wood and condensed for return to the used impregnating solution, the depleted solution is restored to its original composition for recycle to the process by addition of a concentrate of the preservative and antiblooming additive in the solvent. Preferred components of the treating solution and the concentrate are pentachlorophenol, a glycol or glycol derivative, and a relatively low boiling chlorinated solvent such as methylene chloride.
Inventors
- 👤 Harold G Liddell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:00
CPC Classifications
B; B27; B27K; B27K3/00; B27K3/02; B27K3/08; B27K3/0278; B27K3/15; B27K3/153; B27K3/34; B27K3/38; B27K3/40; B27K3/50; B27K5/00; B27K5/001; C; C08; C08L; C08L97/00; C08L97/02; C08L71/00; C08L71/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
81 words
contacting wood with a solution in a halogenated hydrocarbon solvent of 1-2 carbon atoms containing about 2-6 weight percent of a wood preservative and about 0.5-4 weight percent of a glycol component which is at least one of ethylene glycol, propylene glycol, a corresponding liquid polyglycol of molecular weight up to about 4,000, or a lower alkyl monoether thereof at ambient temperature to about 140* C. and at a pressure at least sufficent to maintain the solvent in a liquid state,
Claim 2
Dependent Claim
81 words
contacting wood with a solution in a halogenated hydrocarbon solvent of 1-2 carbon atoms containing about 2-6 weight percent of a wood preservative and about 0.5-4 weight percent of a glycol component which is at least one of ethylene glycol, propylene glycol, a corresponding liquid polyglycol of molecular weight up to about 4,000, or a lower alkyl monoether thereof at ambient temperature to about 140* C. and at a pressure at least sufficent to maintain the solvent in a liquid state,
Claim 3
Dependent Claim
10 words
In a process for impregnating wood which comprises the steps:
Claim 4
Dependent Claim
10 words
In a process for impregnating wood which comprises the steps:
Claim 5
Dependent Claim
14 words
removing excess solution from contact with the wood and returning it to storage means,
Claim 6
Dependent Claim
14 words
removing excess solution from contact with the wood and returning it to storage means,
Claim 7
Dependent Claim
16 words
The process of claim 1 wherein the solution is pentachlorophenol and glycol component in methylene chloride.
Claim 8
Dependent Claim
131 words
heating the wood at least to the boiling point of the solvent, condensing the thereby vaporized solvent, and combining the condensed solvent with the excess solution, the improvement which consists of adding to the depleted combined excess solution and condensed solvent to restore it to about the composition of the starting solution by adding thereto a concentrate solution containing sufficient wood preservative, glycol and solvent to substantially make-up the preservative, glycol and solvent lost in the treating steps 1-3, said concentrate being of about 10 to about 35 weight percent of said wood preservatives and about 5 to about 55 percent of said glycol component both dissolved in said solvent, thereby to enable the treatment of wood according to steps 1-3 with a treating solution within the concentration of step 1.
Claim 9
Dependent Claim
131 words
heating the wood at least to the boiling point of the solvent, condensing the thereby vaporized solvent, and combining the condensed solvent with the excess solution, the improvement which consists of adding to the depleted combined excess solution and condensed solvent to restore it to about the composition of the starting solution by adding thereto a concentrate solution containing sufficient wood preservative, glycol and solvent to substantially make-up the preservative, glycol and solvent lost in the treating steps 1-3, said concentrate being of about 10 to about 35 weight percent of said wood preservatives and about 5 to about 55 percent of said glycol component both dissolved in said solvent, thereby to enable the treatment of wood according to steps 1-3 with a treating solution within the concentration of step 1.
Claim 10
Dependent Claim
24 words
The process of claim 2 wherein the glycol component is diethylene glycol, polypropylene glycol of average molecular weight about 750, or a mixture thereof.
Claim 11
Dependent Claim
11 words
The process of claim 1 wherein the wood preservative is pentachlorophenol.
Claim 12
Dependent Claim
11 words
THE PROCESS OF CLAIM 4 WHEREIN THE SOLVENT IS METHYLENE CHLORIDE.
Claim 13
Dependent Claim
12 words
The process of claim 5 wherein the glycol component is diethylene glycol.
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) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |