EP0401044A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Absorbent polymers and their production
Assignee: Ciba Specialty Chemicals Water Treatments Ltd
•
Filing: 1990-06-01
•
Granted: —
•
Expires: 2010-06-01
Abstract
Abstract Fines or other particles of water swellable polymeric material are converted into a gel mass by absorbing an aqueous solution of a cross linking agent into the fines, cross linking occurs between the cross linking agent and pendant groups in the polymer, and the mass is dried and comminuted. The polymer is preferably a cross linked sodium acrylate polymer and the cross linking agent is preferably a glycidyl ether or a silane cross linking agent. The product is novel and comprises a polymer structure that is formed of zones in which the polymer is substantially free of cross links between pendant groups, and the zones are interconnected by cross links through the pendant groups.
Inventors
- 👤 Ian Michael Johnson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 20:43
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/24; C08J3/12; C08J2300/00; C08J2300/14
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
76 words
A process of making water insoluble, water swellable, particulate polymeric material from dry particles of a water swellable polymer formed from water soluble ethylenically unsaturated material and which comprises forming a gel mass by absorbing aqueous solution of cross linking agent into the said dry particles, causing cross linking of the polymer in the gel mass by reaction between the cross linking agent and pendant groups in the polymer, and drying and comminuting the gel mass.
Claim 2
Dependent Claim
76 words
A process of making water insoluble, water swellable, particulate polymeric material from dry particles of a water swellable polymer formed from water soluble ethylenically unsaturated material and which comprises forming a gel mass by absorbing aqueous solution of cross linking agent into the said dry particles, causing cross linking of the polymer in the gel mass by reaction between the cross linking agent and pendant groups in the polymer, and drying and comminuting the gel mass.
Claim 3
Dependent Claim
46 words
A process according to claim 1 in which the said dry particles are formed from water soluble ethylenically unsaturated material comprising polyethylenically unsaturated cross linking agent and are swellable, water insoluble, particles and have a gel capacity of at least 20g deionised water per gram polymer.
Claim 4
Dependent Claim
46 words
A process according to claim 2 in which the dry particles have a moisture content of up to 20% and the amount of water introduced by the aqueous solution is from 30 to 70% by weight based on the weight of particles and added aqueous solution.
Claim 5
Dependent Claim
18 words
A process according to claim 2 in which the polymer particles are anionic, water swellable, water insoluble particles.
Claim 6
Dependent Claim
38 words
A process according to claim 2 in which the polymer particles are formed from 30 to 100% acrylic acid or water soluble salt thereof with 0 to 70% acrylamide and are cross linked, water insoluble, water swellable particles.
Claim 7
Dependent Claim
28 words
A process according to claim 2 in which the cross linking agent is a covalent cross linking agent that will react covalently with pendant groups in the polymer.
Claim 8
Dependent Claim
41 words
A process according to any preceding claim in which the polymer is anionic and contains carboxylic groups and the cross linking agent is selected from silane coupling agents and materials providing at least two groups selected from hydroxyl and epoxide groups.
Claim 9
Dependent Claim
32 words
A process according to any preceding claim in which the polymer is an anionic polymer containing carboxyl groups and the cross linking agent is selected from silane coupling agents and glycidyl ethers.
Claim 10
Dependent Claim
36 words
A process according to any preceding claim comprising absorbing the said aqueous solution into the said dry particles and subsequently or simultaneously blending the product of this absorption by a polymer gel made by gel polymerisation.
Claim 11
Dependent Claim
54 words
A process according to any preceding claim in which the dry particles are made by sieving fines from a product made by reverse phase bead polymerisation or from a product made by drying and comminuting gel particles made either by reverse phase bead polymerisation or by comminution of gel made by bulk gel polymerisation.
Claim 12
Dependent Claim
22 words
A process according to claim 10 in which at least 90% by weight of the fines have a particle size below 100µm.
Claim 13
Dependent Claim
56 words
A water insoluble, water swellable, particulate polymeric material formed from ethylenically unsaturated material, wherein the polymeric material has a polymer structure that is formed of zones in which the polymer is substantially free of cross links between pendant groups in the polymer and the zones are interconnected by cross links through pendant groups in the polymer.
Claim 14
Dependent Claim
56 words
A water insoluble, water swellable, particulate polymeric material formed from ethylenically unsaturated material, wherein the polymeric material has a polymer structure that is formed of zones in which the polymer is substantially free of cross links between pendant groups in the polymer and the zones are interconnected by cross links through pendant groups in the polymer.
Claim 15
Dependent Claim
34 words
A polymeric material according to claim 12 in which the polymer has carboxylic pendant groups and has a cross linked polymeric backbone, and the cross links are provided by a covalent cross linking agent.
Claim 16
Dependent Claim
41 words
A polymer according to claim 12 formed from 30 to 100% acrylic acid as free acid or water soluble salt and 0 to 70% acrylamide and in which the cross links are provided by a glycidyl ether or silane coupling agent.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.