Patent US4152199A successfully refreshed from Google Patents.
US4152199A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Interpolymer paper strength additives
Assignee: United States Department of Agriculture
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Filing: 1975-05-30
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Granted: 1979-05-01
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Expires: 1995-05-30
Abstract
Abstract Crosslinked starch-polyamide-polyamine interpolymers are prepared and described. Wet- and dry-tensile, dry-burst, and concora crush strengths of paper products, prepared from both acid and alkaline pulp furnishes, are significantly increased by the wet-end addition of the interpolymers.
Inventors
- 👤 George E. Hamerstrand
- 👤 Merle E. Carr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:44
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/21; D21H17/24; D21H17/28; D21H17/33; D21H17/46; D21H17/54; D21H17/55; D21H21/00; D21H21/14; D21H21/18
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
133 words
In the production of paper products an improvement which comprises the following steps: a. adding to a paper pulp from about 0.125% to 1% o.d. (based on weight of oven dried pulp fibers) of a polyamide-polyamine-epichlorohydrin resin (PAE) having the following repeating unit: ##STR12## where R=the following substituents in the approximate ratios of 3:1:1: ##STR13## equals from about 65 to about 130 based on a unit weight of 300, said resin having a molecular weight range of 20,000 to 40,000; b. reacting from about 0.5% to 2.5% o.d. of sodium starch xanthate having a xanthate degree of substitution of from 0.1 to 3 with the PAE contained in the paper pulp resulting from step (a) for from 2 to 30 minutes; and c. making paper from the paper pulp resulting from step (b).
Claim 2
Dependent Claim
133 words
In the production of paper products an improvement which comprises the following steps: a. adding to a paper pulp from about 0.125% to 1% o.d. (based on weight of oven dried pulp fibers) of a polyamide-polyamine-epichlorohydrin resin (PAE) having the following repeating unit: ##STR12## where R=the following substituents in the approximate ratios of 3:1:1: ##STR13## equals from about 65 to about 130 based on a unit weight of 300, said resin having a molecular weight range of 20,000 to 40,000; b. reacting from about 0.5% to 2.5% o.d. of sodium starch xanthate having a xanthate degree of substitution of from 0.1 to 3 with the PAE contained in the paper pulp resulting from step (a) for from 2 to 30 minutes; and c. making paper from the paper pulp resulting from step (b).
Claim 3
Dependent Claim
126 words
In the production of paper products an improvement which comprises the following steps: a. adding to a paper pulp the composition prepared by reacting from about 0.125% to 1% o.d. (based on weight of oven dried pulp fibers) of a polyamide-polyamide-epichlorohydrin resin (PAE) having the following repeating unit: ##STR14## where R=the following substituents in the approximate ratios of 3:1:1: ##STR15## equals from about 65 to about 130 based on a unit weight of 300, said resin having a molecular weight range of 20,000 to 40,000 with from about 0.5% to 2.5% o.d. of sodium starch xanthate having a xanthate degree of substitution of from 0.1 to 0.3 for from about 2 to 30 minutes; and b. making paper from the paper pulp resulting from step (a).
Claim 4
Dependent Claim
126 words
In the production of paper products an improvement which comprises the following steps: a. adding to a paper pulp the composition prepared by reacting from about 0.125% to 1% o.d. (based on weight of oven dried pulp fibers) of a polyamide-polyamide-epichlorohydrin resin (PAE) having the following repeating unit: ##STR14## where R=the following substituents in the approximate ratios of 3:1:1: ##STR15## equals from about 65 to about 130 based on a unit weight of 300, said resin having a molecular weight range of 20,000 to 40,000 with from about 0.5% to 2.5% o.d. of sodium starch xanthate having a xanthate degree of substitution of from 0.1 to 0.3 for from about 2 to 30 minutes; and b. making paper from the paper pulp resulting from step (a).
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) | 1982-04-30 | 1982-10-30 | 1983-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-30 | 1986-10-30 | 1987-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-30 | 1990-10-30 | 1991-05-01 | $7700.00 | Window Closed / Lapsed |