EP0195550A1
Expired / Lapsed
EP
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Water absorbing polymers
Assignee: Ciba Specialty Chemicals Water Treatments Ltd
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Filing: 1986-03-04
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Granted: —
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Expires: 2006-03-04
Abstract
Abstract A slurry or cake is converted to a crumbly state by admixture, in the absence of a polymeric binder, with water swellable, cross-linked, non-sticky, wholly synthetic polymer particles formed of a polymer of acrylic acid (as free acid or water soluble salt) with cross-linking agent and, optionally, acrylamide and/or other monomers.
Inventors
- 👤 Peter Flesher
- 👤 John Clarke
- 👤 David Marshall
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 18:11
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
124 words
A process in which a wet particulate mass which is not crumbly at a predetermined temperature is mixed with water absorbent polymer particles that absorb free water from the mass and the resultant mixture is crumbled at the said temperature characterised in that the mixture is free of polymeric binder, the polymer particles are substantially non-sticky when swollen with water, and the polymer is a non-film forming, wholly synthetic, polymer of (a) 5 to 100 mole per cent acrylic acid (as free acid or water soluble salt), (b) 0 to 95 mole per cent acrylamide, (c) 0 to 50 mole per cent other monoethylenically unsaturated monomers selected from non-ionic and anionic monomers and (d) 10 to 10,000 ppn (by weight total monomers) cross-linking agent.
Claim 2
Dependent Claim
124 words
A process in which a wet particulate mass which is not crumbly at a predetermined temperature is mixed with water absorbent polymer particles that absorb free water from the mass and the resultant mixture is crumbled at the said temperature characterised in that the mixture is free of polymeric binder, the polymer particles are substantially non-sticky when swollen with water, and the polymer is a non-film forming, wholly synthetic, polymer of (a) 5 to 100 mole per cent acrylic acid (as free acid or water soluble salt), (b) 0 to 95 mole per cent acrylamide, (c) 0 to 50 mole per cent other monoethylenically unsaturated monomers selected from non-ionic and anionic monomers and (d) 10 to 10,000 ppn (by weight total monomers) cross-linking agent.
Claim 3
Dependent Claim
18 words
A process according to claim 1 in which the polymer particles have a surface layer of reduced swellability.
Claim 4
Dependent Claim
37 words
A process according to claim 1 in which the polymer particles have a surface layer of reduced swellability as a result of surface of the particles having been additionally cross-linked, preferably by reaction with polyvalent metal ions.
Claim 5
Dependent Claim
33 words
A process according to any one of claims 1 to 3 in which the polymer particles are formed of 80 to 100 per cent sodium acrylate and 0 to 20 per cent acrylamide.
Claim 6
Dependent Claim
21 words
A process according to any one of claims 1 to 4 in which the polymer particles are formed of sodium polyacrylate.
Claim 7
Dependent Claim
33 words
A process according to any one of claims 1 to 3 in which the polymer particles are formed of 10 to 50 per cent sodium acrylate and 50 to 90 per cent acrylamide.
Claim 8
Dependent Claim
24 words
A process according to any preceding claim in which the polymer particles have a gel capacity of 100 to 1,000, preferably 300 to 700.
Claim 9
Dependent Claim
21 words
A process according to any preceding claim in which the polymer particles have a dry size of 50 to 500 um.
Claim 10
Dependent Claim
42 words
A process according to any preceding claim in which the wet mass will freeze solid at below 0°C, is mixed with the polymer particles at above 0°C while in a container and is crumbled and discharged from the container while below 4°C.
Claim 11
Dependent Claim
53 words
A process according to any one of claims 1 to 8 in which the wet mass is a slurry or wet cake and is mixed with the absorbent polymer at a temperature above 0°C and is thereby converted to a crumbly state and the resultant mixture is crumbed at a temperature above 0°C.
References Cited (Backward Citations)
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