METHOD FOR PROVIDING ARTIFICIAL DENTURES WITH A SOFT HYDROGEL LAYER

摘要

1,186,480. Dentures. CESKOSLOVENSKA AKADEMIE VED. 2 Aug., 1968 [16 Aug., 1967], No..37012/68. Heading A5R. [Also in Division C3] Artificial dentures are provided with a. soft hydrogel layer by polymerising as a layer onto the surface of the hard polymer of which the denture is composed, using a polymerisation initiator, a mixture of a non-crosslinked, soluble glycol mono-acrylate or -methacrylate polymer or copolymer, monomeric glycol mono-acrylate or -methacrylate containing 0.05-2.00% by weight (based on total monomer) of the corresponding diester, and a water soluble, substantially anhydrous solvent capable of dissolving said non-crosslinked polymer as well as the hard polymer of the denture, the solvent being used in an amount of 5-50% by weight (based on the total mixture); and thereafter completely removing said solvent by washing and replacing it by water. The denture may be composed of methyl methacrylate, ethyl methacrylate or benzyl methacrylate polymer. Polymerisation initiators specified are methyl ethyl ketone hydroperoxide, diisopropyl percarbonate, benzoyl peroxide and persulphates; these may be used in conjunction with a reducing agent such as 2-diethylaminoethyl acetate, dimethylaniline or p-toluene sulphinic acid. Preferred watersoluble solvents are ethylene glycol mono-acetate and glycerol diacetates; other suitable solvents include mono-lower alkyl ethers of ethylene glycol or polyethylene glycol, dimethylformamide, monomethylformamide, formamide and glacial acetic acid. The glycol component of the (meth) acrylate may be ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol or 1,4-butylene glycol. In one Example, a red pigment and finely divided silica are included in the hydrogel layer.