Abstract: A product, especially a master-batch for producing thermally expandable compositions, is obtainable or obtained by reacting, preferably by extruding, a mixture including: (a) at least one polymer P, cross-linkable by peroxide, and (b) at least one coagent, especially an acrylate A, and (c) at least one peroxide PE, wherein the mixture is reacted such that the product has an average melt flow index (MFI) of between 0.1 and 8 g/10 min.

Abstract: A composition for an expandable sealant including at least one polymeric material selected from the group consisting of low density polyethylenes (LDPE), linear low density polyethylenes (LLPDE), ethylene vinyl acetate (EVA), ethylene methacrylate (EMA), and ethylene-butyl acrylate (EnBA); and a chemical blowing agent, wherein the composition is substantially free of a cross-linking agent.

Abstract: Disclosed is a thermally expandable composition, comprising at least one polymer P, cross-linkable by peroxide, and between 1 wt.-% and 2.5 wt.-%, based on the total weight of the composition, of at least one acrylate A, and between 0.2 wt.-% and 2.5 wt.-%, based on the total weight of the composition, of at least one peroxide, and at least one blowing agent, characterised in that the equivalent ratio of said peroxide to said acrylate A is between 0.01 and 0.5, preferably between 0.13 and 0.41, and the weight ratio of said peroxide to said acrylate A is lower than 0.33 and said polymer P comprises or essentially consists of at least two polymers PI and P2, wherein PI exhibits a melt flow index (MFI) of between 100 and 200 g/10 min, and P2 exhibits a melt flow index of between 0.1 and 60 g/10 min, wherein MFI is determined by ASTM D1238.

Abstract: A composition for an expandable sealant including at least one polymeric material selected from the group consisting of low density polyethylenes (LDPE), linear low density polyethylenes (LLPDE), ethylene vinyl acetate (EVA), ethylene methacrylate (EMA), and ethylene-butyl acrylate (EnBA); and a chemical blowing agent, wherein the composition is substantially free of a cross-linking agent.

Abstract: Disclosed is a thermally expandable composition, comprising at least one polymer P, cross-linkable by peroxide, and between 1 wt.-% and 2.5 wt.-%, based on the total weight of the composition, of at least one acrylate A, and between 0.2 wt.-% and 2.5 wt.-%, based on the total weight of the composition, of at least one peroxide, and at least one blowing agent, characterised in that the equivalent ratio of said peroxide to said acrylate A is between 0.01 and 0.5, preferably between 0.13 and 0.41, and the weight ratio of said peroxide to said acrylate A is lower than 0.33 and said polymer P comprises or essentially consists of at least two polymers PI and P2, wherein PI exhibits a melt flow index (MFI) of between 100 and 200 g/10 min, and P2 exhibits a melt flow index of between 0.1 and 60 g/10 min, wherein MFI is determined by ASTM D1238.