| 摘要 |
1,268,115. Dental filling materials. JOHNSON & JOHNSON. 13 June, 1969 [14 June, 1968], No. 30149/69. Heading C3P. Packaged dental filling materials for preparing cured dental fillings comprise a two-part system, one of said parts being a paste consisting of a binder system comprising a colourless binder monomer which is a bisphenol A derivative having at least two terminal acrylate or methacrylate ester groups, at least 65% by weight of a finely divided filler and a free radical polymerization catalyst; and the other of said parts being a paste containing substantially the same monomer as in the first part, at least 65% by weight of a finely divided filler and an activator for said catalyst. Polymerization is initiated when the two packaged parts are blended together. The preferred binder monomer is that of the formula The viscosity of the monomer can be adjusted by diluting with another monomer such as methyl methacrylate or a glycol dimethacrylate, e.g. triethylene glycol dimethacrylate. Benzoyl peroxide is a suitable catalyst and the activator may be, for example, N,N.dimethyl.p-toluidine or p-toluenesulphinic acid. Preferred as fillers are inorganic materials such as fused silica, aluminium oxide, crystalline quartz and glass beads. The filler may be treated with a keying agent, e.g. an ethylenically unsaturated organosilane, to improve the bond between the polymerized binder and the filler particles. Optional components which may be added include inhibitors such as butylated hydroxy-toluene, U.V. absorbers such as 2-hydroxy-4-methoxy-benzophenone, and submicron particle material, e.g. hydrophobic submicron silica, to prevent possible slight separation between binder monomer and filler. Pigment can be included in one of the parts to obtain any desired colour shade; in the example unspecified organic dyes are used. |
