HIGHLY DAMPING EXPANDABLE MATERIAL AND DEVICES

摘要

A thermally expandable material comprising: a) from 3 to 40 % by weight of a first thermoplastic elastomer having a first glass transition temperature, b) from 3 to 40 % by weight of a second thermoplastic elastomer having a second glass transition temperature, wherein the first and the second glass transition temperature differ by at least 10 °C c) from 5 to 50 % by weight of at least one thermoplastic polymer selected from the group consisting of polymers and copolymers with at least one polymerizable C = C double bond, d) from 0 to 30% by weight of at least one tackifying resin, e) at least one latent chemical blowing agent in an amount effective to cause the expandable material to expand at least 50 % in volume when heated at a temperature of 150 °C for at least 20 minutes, wherein the sum of components a) to e) is less than 100 % by weight, and the remainder to 100 % by weight is made up of further components or adjuvants. Preferably, the material comprises: a first thermoplastic elastomer which has a glass transition temperature in the range from -25 to 0.0 °C, a second thermoplastic elastomer which has a glass transition temperature in the range from 0.1 to 30 °C, at least one thermoplastic polymer c) selected from the group consisting of ethylene/vinyl acetate copolymers and ethylene/methyl acrylate copolymers, at least one latent chemical blowing agent, at least one curing agent based on sulfur and/or sulfur compounds. The material can be used for various sound-dampening applications like dissipative vibratory wave barriers, sound dampening of automotive closure panel assemblies, cavity filler inserts, and constrained layer damping structures.