In order to meet the needs of all aspects of agricultural production, agricultural plastic film has a variety of different varieties and specifications. According to the use of different plastic raw materials, divided into polyvinyl chloride plastic film, polyethylene plastic film; According to the plastic film production methods are different, divided into the pressure film, blown film; according to the plastic film has some special properties, respectively, seedling film, no drip film, colored film, ultra-thin cover film, wide film, Packaging film and so on. According to the different thickness and width of plastic film, there are a variety of different specifications.
Polyvinyl chloride and polyethylene plastic film
PVC film and polyethylene film, is currently the largest amount of agricultural production of the two plastic film. Among them, the PVC film, because of a better overall performance, is China's agricultural production to promote the application of the longest, the largest number of one. Polyethylene film is widely used in recent years, the variety, because of its superior performance, the amount is growing significantly, now these two kinds of agricultural plastic film performance characteristics of a simple comparison as follows:
1. Polyvinyl chloride film mechanical strength, anti-aging performance is better, good elasticity, after stretching can be restored; and polyethylene film mechanical strength of about 70 percent of polyvinyl chloride film, toughness and resilience Poor, light transmission and surface aging properties of PVC film, if the film is not made in the production of adequate anti-aging materials, it is easy in the strong sunlight under the surface of the early cracks, embrittlement and other phenomena. However, during use, the mechanical strength of the polyethylene film decreases with time and is smaller than that of the polyvinyl chloride film.
2. Polyethylene film permeability and heat conduction rate than the PVC film. In general, the heat transfer speed, plastic film greenhouse heat loss is also large. Therefore, the thermal insulation properties of PVC film than polyethylene film is good, warming effect is more significant. According to the test, the average temperature of the polyethylene film is lower than that of the polyvinyl chloride film.
3. In the PVC film greenhouse, when the water vapor increases, easy to attach to the film, the formation of mist and water, resulting in shed seedlings seedlings. In the case of polyethylene slabs, the situation is much better, because it is smooth, when the water vapor in the shed when the water picking, along the membrane wall into the soil.
4. PVC film and polyethylene film damage, can be used thermal welding and adhesive repair. But with adhesive repair polyethylene film effect, it is better to repair PVC film is good.
5. Polyethylene film through the light faster than the PVC film slow. However, PVC film easily sticks to dust, washing is also more difficult to use for a long time, its light transmission performance is often worse than the polyethylene film.
6. PVC film washed, if the water stains are not wiping or dry, on the collection custody, easy on the surface of the film to form a white water stains; in the stacking, if not sprinkle with some talc, Or by the pressure, it is easy to make the film together. While the polyethylene film is not breeding these shortcomings, washing, collection are more convenient.
7. The polyethylene film has a small specific gravity of only about 76% of the polyvinyl chloride film. So that the original need to use one hundred kilograms of PVC film cover the land area, switch to polyethylene film, just about eight kilograms can be.
8. Polyvinyl chloride film in the manufacture, the use of auxiliary materials and the number of more varieties, the production process is also more difficult to control the process; and polyethylene film forming and processing, can be used blow molding method to produce a wide width of the film, In use can save a lot of splicing film labor and time.