US4902382A
Expired / Lapsed
US
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Process for producing a neutral paper
Assignee: Hokuetsu Corp
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Filing: 1988-09-29
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Granted: 1990-02-20
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Expires: 2008-09-29
Abstract
Abstract A neutral wood containing paper can be produced by adding, to a stock slurry containing mineral filler and a large majority of high yield pulp, a cationized starch, and thereafter bentonite and colloidal silica either simultaneously or successively with a time interval of at most 60 seconds, resulting in an improved retention of fiber and filler, an improved drainage, and a decreased pitch problem.
Inventors
- 👤 Takao Sakabe
- 👤 Akira Honma
- 👤 Takao Miyamura
- 👤 Hiroshi Suzuki
- 👤 Yoshihito Meguro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:32
CPC Classifications
D; D21; D21H; D21H23/00; D21H23/02; D21H23/04; D21H23/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
166 words
A process for producing a neutral paper which comprises adding to a stock slurry comprising filler and pulp comprising 0 to 100 weight percent high yield pulp having a pH ranging from 6 to 9, first a cationized starch and thereafter bentonite and colloidal silica either simultaneously or successively with a time interval of at most 60 seconds, then pouring the stock slurry over the wire of a paper making machine to form a web layer, and drying the web layer, wherein the bentonite has a swelling degree (grams of water-swelled bentonite/gram of bentonite) of at least 5, the amount of bentonite is in the range of 0.05 wt. % to 2 wt. % based on cellulose, the amount of colloidal silica is in the range of 0.01 wt. % to 1.0 wt. % based on cellulose, the weight ratio of colloidal silica/bentonite is in the range of 1/0.5 to 1/15, and the weight ratio of colloidal silica/cationized starch is the range of 1/1 to 1/25.
Claim 2
Dependent Claim
166 words
A process for producing a neutral paper which comprises adding to a stock slurry comprising filler and pulp comprising 0 to 100 weight percent high yield pulp having a pH ranging from 6 to 9, first a cationized starch and thereafter bentonite and colloidal silica either simultaneously or successively with a time interval of at most 60 seconds, then pouring the stock slurry over the wire of a paper making machine to form a web layer, and drying the web layer, wherein the bentonite has a swelling degree (grams of water-swelled bentonite/gram of bentonite) of at least 5, the amount of bentonite is in the range of 0.05 wt. % to 2 wt. % based on cellulose, the amount of colloidal silica is in the range of 0.01 wt. % to 1.0 wt. % based on cellulose, the weight ratio of colloidal silica/bentonite is in the range of 1/0.5 to 1/15, and the weight ratio of colloidal silica/cationized starch is the range of 1/1 to 1/25.
Claim 3
Dependent Claim
218 words
A process for producing a neutral paper which comprises adding, to a stock slurry comprising a filler and pulp comprising 0 to 100 weight percent high yield pulp having a pH ranging from 6 to 9, first a water-soluble aluminum salt, and a cationized starch, and thereafter bentonite and colloidal silica either simultaneously or successively with a time interval of at most 60 seconds, then forming a wet web layer on a wire of paper machine from the stock slurry, and drying the web layer, wherein the water-soluble aluminum salt is selected from the group consisting of aluminum sulfate, polyaluminum chloride, sodium aluminate, and polydiallyldimethylaluminumchloride, and the amount of water-soluble aluminum salt calculated as Al 2 O 3 based on cellulose is in the range of 0.01 wt. % to 1.0 wt. %, the bentonite has a swelling degree (grams of water-swelled bentonite/gram of bentonite) of at least 5, the amount of bentonite is in the range of 0.05 wt. % to 2 weight % based on cellulose, the amount of colloidal silica is in the range of 0.01 wt. % to 1.0 wt. % based on cellulose, the weight ratio of colloidal silica/bentonite is in the range of 1/0.5 to 1/15, and the weight ratio of colloidal silica/cationized starch is in the range of 1/1 to 1/25.
Claim 4
Dependent Claim
218 words
A process for producing a neutral paper which comprises adding, to a stock slurry comprising a filler and pulp comprising 0 to 100 weight percent high yield pulp having a pH ranging from 6 to 9, first a water-soluble aluminum salt, and a cationized starch, and thereafter bentonite and colloidal silica either simultaneously or successively with a time interval of at most 60 seconds, then forming a wet web layer on a wire of paper machine from the stock slurry, and drying the web layer, wherein the water-soluble aluminum salt is selected from the group consisting of aluminum sulfate, polyaluminum chloride, sodium aluminate, and polydiallyldimethylaluminumchloride, and the amount of water-soluble aluminum salt calculated as Al 2 O 3 based on cellulose is in the range of 0.01 wt. % to 1.0 wt. %, the bentonite has a swelling degree (grams of water-swelled bentonite/gram of bentonite) of at least 5, the amount of bentonite is in the range of 0.05 wt. % to 2 weight % based on cellulose, the amount of colloidal silica is in the range of 0.01 wt. % to 1.0 wt. % based on cellulose, the weight ratio of colloidal silica/bentonite is in the range of 1/0.5 to 1/15, and the weight ratio of colloidal silica/cationized starch is in the range of 1/1 to 1/25.
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) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |