| 摘要 |
1,149,911. Polyurethane graft polymers. SCOTT PAPER CO. 12 May, 1966 [19 May, 1965], No. 21216/66. Headings C3C, C3G and C3R. A hydrophilic, porous polyurethane foam is produced by grafting a water-soluble or watermiscible monomer on to a hydrophobic, porous, polyurethane foam in the presence of an organic free radical initiator. The polyurethane foam may be one prepared from a polyester, e.g. a glycol-adipate polyester resin and toluene diisocyanate in the presence of a wetting agent, N-ethyl morpholine and water, or from a polyether or polyether amine. In one embodiment the foam, which may be open-celled or reticulate and may be compressed and heated prior to grafting, is submerged in an aqueous medium containing the monomer e.g. acrylic acid, hydroxyethyl acrylate, (meth)acrylamide, dimethylaminoethyl methacrylate, polyethylene glycol (meth)acrylate or an analogous derivative of chloracrylic, cyanoacrylic acid or ethacrylic acid, or a monoester of maleic or fumaric acid and ethylene or propylene glycol. The catalyst is benzoyl peroxide, optionally together with dimethyl aniline as promoter and the polymerization medium may also contain an oxygen scavenger e.g. sodium bisulphite and a conventional wetting agent. Alternatively, the foam is impregnated with a solution of the initiator prior to contact with the monomer. The foam may be mechanically worked during the polymerization, which is preferably carried out under N 2 . After polymerization, a graft polymer formed from an acid monomer may be treated e.g. with Na 2 CO 3 , K 2 CO 3 , CH 3 CO 2 K or (CH 3 CO 2 ) 2 Ca to convert acid groups to salt groups. In the examples the monomers used are acrylic acid, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate and acrylamide and a mixture of the first two of said monomers. Mercaptosuccinic acid is used as a molecular weight regulator and acetic acid as a solvent for the benzoyl peroxide in Example 12.
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