Patent ID: 9576568
Date: 2017-02-21
CPC Classifications: B32B,G10K

Claim:
1. A polymer interlayer having improved sound insulation, the polymer interlayer comprising: at least one soft layer wherein the soft layer comprises a blend of two or more poly(vinyl butyral) resins comprising: a first poly(vinyl butyral) resin having a first residual hydroxyl content; a second poly(vinyl butyral) resin having a second residual hydroxyl content, wherein the difference between the first residual hydroxyl content and the second residual hydroxyl content is at least 1.0 weight percent; a high refractive index plasticizer having a refractive index of at least 1.460, wherein the first poly(vinyl butyral) resin, the second poly(vinyl butyral) resin and the high refractive index plasticizer are mixed and melt-extruded to form the at least one soft layer; at least one stiffer layer comprising a third poly(vinyl butyral) resin having a third residual hydroxyl content; and a plasticizer, wherein the difference between the third residual hydroxyl content and at least one of the first residual hydroxyl content and the second residual hydroxyl content is at least 2.5 weight percent.