New ultrathermic films for greenhouse covers

Thermic greenhouse covers are plastic films that block infrared (7-14 mu m) radiation to reduce the risk of frost when the greenhouse is not heated and to reduce the energy consumption when a heating system is used. The standard mineral fillers (calcined kaolin), which have been normally used to increase the IR opacity of LDPE and other greenhouse films, accelerate the photodegradation of the film as well as moderately increase the haze and diminish the light transmission. In this work, we present a new family of mineral fillers that do not accelerate photodegradation, do not lower the light transmission, and give low or high haze, depending on what is required. With these mineral fillers, the optical properties can be optimized and the IR effectiveness can be reached, thus giving a new generation of ultrathermic films (UT). Using them as greenhouse covers, heat energy savings between 5% and 10% can be achieved.