Patent ID: 8313838

Claim:
A sound dampening interlayer film for laminated glass comprising at least two individual films of plasticizer-containing polyvinyl acetal, wherein a first individual film (A) comprises a polyvinyl acetal with a content of polyvinyl acetate groups of 0.1 to 11 mol % and a content of polyvinyl alcohol groups of 17 to 22% by weight, a second individual film (B) comprises a polyvinyl acetal with a content of polyvinyl acetate groups of between 5 and 7.9 mol %, and a content of polyvinyl alcohol groups of 11.5 to 13% by weight, the polyvinyl acetate group contents and/or plasticizer content being different in the respective films, and wherein the individual films have a plasticizer content which differs by at least 10% by weight, the plasticizer content of the second film (B) being higher than the first film (A).