| 摘要 |
An expanded film suitable for plastic coverings for greenhouses and tunnels and for heated mulching of soil, with improved greenhouse effect compared to close-packed neutral films made of the same base polymer, comprising one or more layers of expanded plastic material, at least one of the layers being constituted by an alpha -olefin and a vinyl ester copolymer. Particularly significant are ethylene-vinyl acetate copolymers containing from 3 to 28 % of vinyl acetate by weight, which, by means of microcellular expansion, can be upgraded from films suitable for "standard" coverings for farming purposes to "diffuse-light thermal" film. |
