Patent US3630834A successfully refreshed from Google Patents.
US3630834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sizing paper with isothiouronium salts of polyglycidyl ethers of polyhydric phenols
Assignee: Dow Chemical Co
•
Filing: 1970-05-01
•
Granted: 1971-12-28
•
Expires: 1990-05-01
Abstract
Abstract A process for sizing paper by adding a water-soluble isothiouronium salt of a polyglycidyl ether of a polyhydric phenol to an acid or neutral slurry of cellulose pulp, adjusting the pulp pH to about 8-10 and then forming and drying the paper sheet. Preferably the salt is the thiourea derivative of a diglycidyl ether of a bisphenol.
Inventors
- 👤 Bart J Bremmer
- 👤 Fred J Meyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:40
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/33; D21H17/46; D21H17/58; C; C08; C08G; C08G59/00; C08G59/18; C08G59/40; C08G59/4007; C08G59/4014; C08G59/4021; C08L; C08L63/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
30 words
The process of claim 1 where about 0.1-2.0 wt. percent of the isothiouronium salt is added as the sizing agent and the paper sheet is dried at about 100*-150* C.
Claim 2
Dependent Claim
38 words
The process of claim 1 where the isothiouronium salt is the bisisothiouronium chloride of a bisphenol-epichlorohydrin glycidyl ether of the formula: where R is H or C1-C2 alkyl, R'' is H or C1-C18 alkyl, and n is 0-3.
Claim 3
Dependent Claim
11 words
The process of claim 3 where R and R'' are -CH3.
Claim 4
Dependent Claim
13 words
The process of claim 3 where R is -CH3 and R'' is -(CH2(16CH3.
Claim 5
Dependent Claim
22 words
The process of claim 1 where the isothiouronium salt is the bisisothiouronium chloride of a phenol-formaldehyde novolac glycidyl ether of the formula:
Claim 6
Dependent Claim
22 words
The process of claim 6 where the isothiouronium salt has an average of 2 to 3 isothiouronium groups and n is 0-1.
Claim 7
Dependent Claim
37 words
The process of claim 1 where after adjusting the pulp slurry pH to about 8-10, about 0.2-2.0 parts of polyethylenimine per part of isothiouronium salt is added to the pulp slurry before the paper sheet is formed.
Claim 8
Dependent Claim
54 words
The process of claim 1 where the pulp slurry is treated with about 0.4-1.0 wt. percent of the bisisothiouronium chloride salt of a diglycidyl ether of bisphenol A, the slurry pH is adjusted to about 8-10, about 0.4-1.0 wt. percent PEI added, and the paper sheet is formed and dried at about 100*-150* C.
Claim 9
Dependent Claim
10 words
A cellulosic product sized by the process of claim 9.
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) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |