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US4181639A Expired / Lapsed US ⏱️ 0.0 years remaining

Polymer solutions

Assignee: Bayer AG
•
Filing: 1978-07-25
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Granted: 1980-01-01
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Expires: 1998-07-25
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Abstract

Abstract Aqueous polymer solutions containing water and 5 to 30% by weight of a polymeric mixture of (A) a copolymer, 65 to 90 mole percent of whose structural units, based on polymer, consist of statistically distributed residues of acrylamide and 10 to 35 mole percent of residues of maleic acid or maleic acid anhydride, and which has an intrinsic viscosity [η] of 0.05 to 1 [dl/g], and (B) a copolymer whose structural units consist of statistically distributed polymerized residues of acrylamide, acrylic acid and maleic acid, at least some of the maleic acid residues being present in salt form, which has an intrinsic viscosity [η] of from 0.05 to 1.5 [dl/g] and which contains from 65 to 90 mole percent, based on polymer, of residues of acrylamide and residues of acrylic acid together and from 10 to 35 mole percent of residues of maleic acid, at least some of which are present in salt form, the ratio of weight of copolymer (A) to copolymer (B) being from 1:2 to 20:1.

Inventors

  • 👤 Bruno Bomer
  • 👤 Hildegard Schnoring
  • 👤 Rolf Schmidt

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-06 02:20
CPC Classifications
B; B01; B01J; B01J13/00; B01J13/02; B01J13/06; B01J13/10; C; C08; C08L; C08L33/00; C08L33/24; C08L33/26; C08L2205/00; C08L2205/02

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 130 words
Aqueous polymer solutions containing water and 5 to 30% by weight of a polymeric mixture of (A) a copolymer consisting of 65 to 90 mole percent of statistically distributed residues of acrylamide and 10 to 35 mole percent of residues of maleic acid or maleic acid anhydride, and which has an intrinsic viscosity (η) of 0.05 to 1 (dl/g), and (B) a copolymer consisting of 65-90 mole percent of statistically distributed polymerized residues of acrylamide and acrylic acid and 10-35 mole percent of residues of maleic acid, at least some of the maleic acid residues being present in salt from, and said copolymer having an intrinsic viscosity (η) of from 0.05 to 1.5 (dl/g), and the ratio by weight of copolymer (A) to copolymer (B) is from 1:2 to 20:1.
Claim 2
Dependent Claim 130 words
Aqueous polymer solutions containing water and 5 to 30% by weight of a polymeric mixture of (A) a copolymer consisting of 65 to 90 mole percent of statistically distributed residues of acrylamide and 10 to 35 mole percent of residues of maleic acid or maleic acid anhydride, and which has an intrinsic viscosity (η) of 0.05 to 1 (dl/g), and (B) a copolymer consisting of 65-90 mole percent of statistically distributed polymerized residues of acrylamide and acrylic acid and 10-35 mole percent of residues of maleic acid, at least some of the maleic acid residues being present in salt from, and said copolymer having an intrinsic viscosity (η) of from 0.05 to 1.5 (dl/g), and the ratio by weight of copolymer (A) to copolymer (B) is from 1:2 to 20:1.
Claim 3
Dependent Claim 25 words
In the process of producing microcapsules by complex coacervation, the improvement which comprises employing an aqueous copolymer solution of claim 1 as the shell-forming component.

References Cited (Backward Citations)

US3635915A Cited
US3790538A Cited
US3891607A Cited
US3876572A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1982-12-31 1983-07-02 1984-01-01 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1986-12-31 1987-07-02 1988-01-01 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1990-12-31 1991-07-02 1992-01-01 $7700.00 Window Closed / Lapsed

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