| 摘要 |
The invention refers to a multilayer plastic film for perennial agricultural use (1) either in greenhouses or under low tunnels (2) that, self adjusts the shading provided in the covered space (4). The shading effect can be present in the whole surface of the film, or it could be partial at specific surfaces (3) where shading would be most needed. The shading is achieved by incorporating a photochromic compound or a combination of photochromic compounds in a layer of multiple layers in a multilayer film (1). The layer or layers that incorporate the photochromic compound or compounds are protected from oxidation by bilateral layers that incorporate materials that exhibit low permeability to gases and in particular to oxygen. The advantage of said film is that the grower would not need to apply any shading material on the surface of the film and/or any mechanism to facilitate opening and closing of the shading material. |
