Process for the production of highly water-absorbing but less water-soluble hydrogels
AssigneeShowa Denko K.K.
InventorsTooru Yoshida, Seigo Iwagami, Takashi Ueshima, Yoshikazu Hosoda
Life of this patent
Estimating the term…
Abstract
A highly water-absorbing but less water-soluble hydrogel is produced by polymerizing at least one hydrophilic ethylenically unsaturated monomer, e.g., ethylenically unsaturated carboxylic acid, ethylenically unsaturated sulfonic acid, or derivatives thereof, in the presence of a specific difunctional compound, e.g., polyethyleneglycol diglycidyl ether, polyethyleneglycol diacrylate, etc.
Claims20
A process for producing a highly water-absorbing but less water-soluble hydrogel comprising polymerizing at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of a carboxylic acid containing an ethylenically unsaturated group, a sulfonic acid containing an ethylenically unsaturated group, and derivatives thereof to form a homopolymer or copolymer of said hydrophilic ethylenically unsaturated monomer, or a mixture of at least 50% of said hydrophilic ethylenically unsaturated monomer and less than 50% of an ethylenically unsaturated monomer copolymerizable therewith other than said hydrophilic ethylenically unsaturated monomer, in the presence of 0.005% to 20% by weight based on the total weight of the ethylenically unsaturated monomers of at least one difunctional compound selected from the group consisting of compounds represented by the formula (1):
- ##STR13## wherein l is an integer of from 5 to 100.
A process for producing a highly water-absorbing but less water-soluble hydrogel comprising polymerizing at least one hydrophilic ethylenically unsaturated monomer selected from the group consisting of a carboxylic acid containing an ethylenically unsaturated group, a sulfonic acid containing an ethylenically unsaturated group, and their derivatives selected from a carboxylic acid base-containing monomer, an amido-group containing monomer or sodium styrenesulfonate to form a honopolymer or copolymer of said hydrophilic ethylenically unsaturated monomers, or a mixture of at least 50% of said hydrophilic ethylenically unsaturated monomer and less than 50% of ethylenically unsaturated monomer copolymerizable therewith other than said hydrophilic ethylenically unsaturated monomer, in the presence of 0.005% to 20% by weight based on the total weight of the ethylenically unsaturated monomers of at least one difunctional compound represented by formula (4):
- ##STR14## wherein R.sub.3 is hydrogen or a methyl group, p is an integer of from 10 to 150, and q is 0 or an integer of from 1 to 150.
Dependencies are inferred from the claim text.