Maharaj K Gupta

US Patent:

42447771, Jan 13, 1981

Filed:

Nov 7, 1979

Appl. No.:

6/092152

Inventors:

Maharaj K. Gupta - Renton WA

Assignee:

Weyerhaeuser Company - Tacoma WA

International Classification:

D21C 502

US Classification:

162 6

Abstract:

Chlorine dioxide is a specific bleaching agent for stilbene yellow dye which has been used to dye paper stock. Chlorine dioxide may be used in amounts as low as 0. 25% based on the oven dry weight of the pulp fiber.

US Patent:

42160545, Aug 5, 1980

Filed:

Sep 26, 1977

Appl. No.:

5/836449

Inventors:

Jozef M. Bentvelzen - Everett WA
Steven L. Bogart - Everett WA
Maharaj K. Gupta - Renton WA
William T. McKean - Lynnwood WA
Michael D. Meredith - Snohomish WA
Louis O. Torregrossa - Puyallup WA

Assignee:

Weyerhaeuser Company - Tacoma WA

International Classification:

D21C 910

US Classification:

162 57

Abstract:

A slurry of cellulosic fiber and water having a consistency in the range of 0. 017-4. 9% of the total ungassed weight of fiber and water is bleached with ozone. This is done without the usual addition of organic additives. The water can include impurities created by the bleaching process. Rapid reaction times under 8 minutes and preferably under 5 minutes are achieved. The reaction is enhanced in the consistency range of about 0. 017-0. 7%. The slurry is mixed using a mixing energy of 0. 002-1. 0 horsepower per cubic foot of gassed slurry. The mixing energy will determine whether the gas-liquid or liquid-solid interface will limit the speed of the reactions. The passage of ozone from the gas to a liquid phase will be the limiting factor below about 0. 2 horsepower per cubic foot of gassed slurry. The increasing presence of ozone in the liquid as the horsepower increases from about 0.

US Patent:

50716751, Dec 10, 1991

Filed:

Mar 20, 1989

Appl. No.:

7/326187

Inventors:

Maharaj K. Gupta - Renton WA
Amar N. Neogi - Seattle WA
Richard H. Young - Puyallup WA

Assignee:

Weyerhaeuser Company - Tacoma WA

International Classification:

B05D 700

US Classification:

427213

Abstract:

Cellulose fibers are entrained in a gaseous medium and sized while entrained with a sizing material. The sizing material may comprise a nonaqueous solution of alkyl ketene dimer or other sizing material. Also, immersions of fibers in such a nonaqueous sizing solution is another approach for sizing fibers.