What kinds of films are suitable for use in solar greenhouses and what are their characteristics?
By September 15, 2022
There are many kinds of films suitable for solar greenhouse. According to the different resin raw materials, it can be divided into polyethylene (PE) film, polyvinyl chloride (PVC) film and vinyl acetate (EVA) film; According to its performance characteristics, it can be divided into ordinary film, long-life film, drip free film, long-life drip free film, diffuse reflective film, composite multi-functional film, etc. The properties of these films have their own characteristics and strengths. Combined with the current production needs, this paper introduces several commonly used films for reference when building greenhouses.
Types and characteristics of films
(1) Polyethylene ordinary film (PE)
The light transmittance of the new film is about 80%; Weak dust absorption, without the phenomenon of excessive dust absorption (tackiness) caused by plasticizer precipitation of polyvinyl chloride (PVC) film. It has strong low temperature resistance, low temperature brittleness is - 70 ℃, and it can still maintain softness at - 30 ℃. The relative density is 0.92g/cm3, and the infrared transmittance is more than 70%. The heat preservation performance at night is poor, not as good as PVC film. The fog drop property is heavy, and the weather resistance is poor. The service cycle is 4-5 months. It is not sun resistant, and the high temperature softening degree is 50 ℃. Therefore, it is not suitable for covering cultivation in high temperature season. It can be used for covering cultivation in early spring and late autumn. It is not easy to bond after tearing. At present, there is no suitable repair adhesive, and it can only be heat sealed when splicing.
(2) Polyethylene long-life film
It is made of polyethylene as the base resin by blowing after adding a certain proportion of ultraviolet absorber, anti-aging agent and antioxidant. The weather resistance is good, and the service life is 1.5~2 years. The thickness is 0.1~0.12 mm, the amount