Patent ID: 8012612

Claim:
An interlayer for laminated glass, which comprises at least two kinds of layers of (A) an opaque and sound-insulating polyvinyl acetal resin layer containing fine-particle inorganic powder and 55 parts by weight or more of a plasticizer per 100 parts by weight of a polyvinyl acetal resin, and (B) a transparent polyvinyl acetal resin layer, the layers being laminated together, wherein the plasticizer is selected from the group consisting of triethylene glycol di-2-ethylbutyrate, triethylene glycol-di-2-ethylhexanoate, triethylene glycol-di-n-heptanoate, tetraethylene glycol-di-2-ethylhexanoate, tetraethylene glycol-di-n-heptanoate and oligoethylene glycol-di-2-ethylhexanoate, wherein the polyvinyl acetal resin is a polyvinyl butyral resin, wherein the resin of the (A) layer has a vinyl acetate content (residual acetyl groups) of 8 to 30 mol %, wherein the fine particle inorganic powder is selected from the group consisting of calcium carbonate and silica, wherein (B) the transparent polyvinyl acetal resin layer comprises a polyvinyl acetal resin (b) with a vinyl acetate content (residual acetyl groups) of not more than 14 mol % produced by acetalization of a polyvinyl alcohol with an aldehyde having 3 to 4 carbon atoms, and a plasticizer, wherein the amount of the plasticizer in (A) the opaque and sound-insulating polyvinyl acetal resin layer is larger than the amount of the plasticizer in (B) the transparent polyvinyl acetal resin layer, and wherein (A) the opaque and sound-insulating polyvinyl acetal resin layer has a different viscoelastic property than (B) the transparent polyvinyl acetal resin layer.