US3775155A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flame retarding celluloscis using tetrakis (hydroxymethyl) phosphonium chloride
Assignee: Hooker Chemical Corp
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Filing: 1971-11-04
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Granted: 1973-11-27
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Expires: 1991-11-04
Abstract
Abstract A process for imparting flame-retardant character to cellulosic containing material has been devised in which the cullolosic material is impregnated with an aqueous solution of a tetrakis(hydroxymethyl)phosphonium compound, preferably partially neutralized tetrakis(hydroxymethyl)phosphonium chloride, the impregnated material is at least partially dried, e.g., to about 5 to 25 percent by weight moisture retention, without fixation of the phosphonium compound on the material, the partially dried material is cooled and then treated with dry ammonia gas optionally in the presence of water vapor whereby the phosphonium compound is cured on the material and a fire-retardant character is imparted thereto.
Inventors
- 👤 R Eggenweiler
- 👤 J Duffy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 21:31
CPC Classifications
D; D06; D06M; D06M13/00; D06M13/244; D06M13/282; D06M13/285; D06M15/00; D06M15/19; D06M15/37; D06M15/667; Y; Y10; Y10S; Y10S428/00; Y10S428/92; Y10S428/921; Y10T; Y10T442/00; Y10T442/20; Y10T442/2631; Y10T442/2672; Y10T442/2689
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
23 words
The method of claim 1 wherein the impregnated material contains from 5 to 25 percent by weight moisture retention after the heating step.
Claim 2
Dependent Claim
24 words
The method of claim 1 wherein the impregnated material is held at ambient temperature for at least about 1 minute after the heating step.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the cooled material is exposed to steam and gaseous ammonia.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the cooled material is exposed to gaseous ammonia.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein the heated material is cooled by spraying with water and thereafter exposed to gaseous ammonia.
Claim 6
Dependent Claim
11 words
The method of claim 1 wherein phosphonium compound is tetrakis(hydroxymethyl)phosphonium chloride.
Claim 7
Dependent Claim
30 words
The method of claim 1 wherein the phosphonium compound is tetrakis(hydroxymethyl)phosphonium chloride partially neutralized with from about 70 to about 90 percent of the stoichiometric amount of a caustic alkali.
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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |