| 摘要 |
A gastight, heat-stable, multilayered material and a method for the production thereof is described. The multilayered material consists of a layer of a first polymer which consists of a mixture of 99-1% by weight polyolefin and 1-99% by weight polyvinyl alcohol and, optionally, a plasticiser containing alcohol groups, and on at least one side of said layer a layer of a second polymer derived from an olefin copolymer containing hydrolysable silane groups. The first polymer consists of, for example, a mixture of polyethylene and polyvinyl alcohol, while the second polymer consists of, for example, a crosslinked copolymer of ethylene and vinyl alkoxy silane, such as vinyl trimethoxy silane which is crosslinked by hydrolysis and condensation of the silane groups under the action of water and a catalyst. In the production of the multilayered material, the catalyst is provided in a layer separate from the crosslinkable silane group-containing copolymer layer or layers, for example in the layer of polyolefin/polyvinyl alcohol mixture, the catalyst then migrating into the layer or layers of silane group-containing copolymer and crosslinking these layers. The multilayered material is preferably produced by coextrusion. The adhesion between the layers can be improved by providing adhesion layers between the layers, or by incorporating an adhesion-improving agent, such as benzoic acid or tetraisopropyl titanate, in any one of the layers. |
