People use plastic film for many applications which require a lot of properties, specially in agriculture. Most plastic films are available on the market today from polyethylene and polypropylene. However, more and more polyethylene film is practically collected and become post-consumer material actually.
Production process of polyethylene films
PE film or polythene film stands for polyethylene film. The main material to make this film is primary PE. According to demand, manufacturers can add more color, ultraviolet…on the production process. Then, these additives can be in the form of pellets or liquid.
At the first sight, blow film extrusion seems very different from profile extrusion and co extrusion. However, the process is essentially the same. First, workers put a mixture of resin and additives into a hopper to melt them by heat. After heating the molten plastic is forced through a ring shaped die, it forms a tube air. Air is also forced through the die, into the tube. The result is forming a bubble whose sides travel upward. Then, the plastic film is cooled and the blowing film machine will allow to roll it through cylindrical rollers. Finally, the machine cuts it a half or left and roll it into the core to produce plastic film rolls.
At present, although producers keeps the same method to make polyethylene films, they change some input materials. Instead of using primary plastic (PE) totally, they will use a part PE filler masterbatch. Although it is produced based on PE plastic, most of CaCO3 powder accounts for a large amount in this type of masterbatch. Because it helps to improvement against water, liquid or gas and reduce material cost. Besides, they also use color masterbatch to blend and create better color for the product when needed.
The application of PE film in plastic greenhouse
Greenhouse helps farmers to be more proactive in cultivation and increase harvest efficiency. So, building a plastic greenhouse with polyethylene film covering will save not only their money but also time.
In addition, polythene film brings anti-condensation. The condensate droplets reduce the ability to transmit light and can lead to disease problems when they drip on trees. This film has a surface tension reducing agent that allows condensate to flow away rather than droplet form. This condensate control can be sprayed on the surface of a greenhouse (nylon) coating or introduced into the central layer and the effect usually lasts a few years.
Besides, the temperature in the greenhouse depends on the amount of daylight. In the multi-layer film, producers usually add the infrared (IR) substance to the inner layers to keep the heat inside the greenhouse at night. In case, the temperature outside the greenhouse is too high because of strong daylight, plastic covers also help to remain or reduce the temperature inside. This advantage will help you save cooling fees and improve vegetables or fruits taste.