Classification and selection methods for plastic sheds films

       Recently, cainong in various regions successively entered the peak period of membrane purchase versus membrane exchange, and what does cainong know about membrane knowledge?What should be your attention to cainong when buying films?

Current major species of greenhouse shed membranes

       At present, the shed film product structure is expected to evolve towards a multi-layer com - posite and its performance towards a functionalization and synthesis of high light transmission, high heat retention, high strength, long life span and continuous flow drop period, anti mist period and dust control period.Shed film development depending on the raw material being produced, the bulk successively goes through four stages: 1 is the polyethylene (PE) shed film;2 is polyvinyl chloride (PVC) shed membrane;The third was an ethylene vinyl acetate copolymer (EVA) shed membrane;The fourth is a PO membrane, and the fifth generation of five layer coextrusion films that are in the stage of development.

Main characteristics and differences among the various shed films

       PVC (polyvinyl chloride) shed membrane.The film of this class shows good light transmission, and the new membrane exhibits over 85% full light transmission, excellent moisture retention, small heat conductivity, large tensile strength, and strong resistance to wind.Acid and alkali resistance.The disadvantage is a large, equally sized shelter with a film ratio that is 1 / 3 larger in use than polyethylene, causing an increase in cost;Followed by stiffening and embrittlement at low temperature, easy softening and relaxation at high temperature;After the auxiliary is precipitated, the film surface is vacuuming and the light transmission is very poor after a month's general use, the residual film is very polluted to the soil, cannot burn treatment, because of the production of chlorine caused environmental pollution, and is currently used gradually.

       PE shed membrane.The PE shed films are light in texture, soft, easy to shape, light transparent and non-toxic and are suitable for use as various shed films, floor films and are currently the main agricultural film variety in our country.It can be produced according to the farmers' needs for different product types, such as PE aging resistant (single prevention), PE aging resistant droplets (double prevention), and PE aging resistant droplets defogging (triple prevention), which have good aging resistance and spray resistance.Its disadvantages are: poor weather resistance, poor heat retention and not easy to bond.As learned from manager song, more filling membranes for PE are currently used in the market,

       The filling film was based on the original polyethylene shed film, which was reprocessed and the inner surface of the agrofilm treated by a coating method so that the treated shed film, with the functional flow drop mist, was tightly attached to the inside of the shed film forming a layer of agent on the inside surface of the shed film.The moisture inside the shed touches the inside of the shed membrane, a layer of water film is formed which then flows down the shed slope due to its own gravitational potential, thus achieving the efficacy of the mist and the drop.The essential difference from the previous shed films was that the functional agent was found independently of the shed films so that the timing of the mist and drop functions depended entirely on the circumstances of the control of the coating process and the quality of the coating agent and the longevity of the agrofilm, which generally would have been more than a year.

       Certainly the grain filling membrane also presents individual defects.1, the mist flow drop was attached to the surface of the agrofilm so that its adhesion was not as strong.The external force is easy to cause the damage to the coating, so that a dripping drop appears in the place that is easy to be damaged.For example, the aforementioned can occur when a shed is placed, when the interior wall is rubbed with a steel frame in a shed, when a high crop hits an agromembrane, etc.Meanwhile, crops with high temperature and humidity are not easy to use filling membranes, such as cucumber, bitter melon, melon, etc.Nevertheless, flawlessly, even if the above appears, the overall effect of agrofilm will be more obvious than that of conventional agrofilm.It is favored by numerous cainong because of the obvious advantages of mist droplet effect of this product and its relatively low cost, which is about 1.1-1.3 RMB per square meter and less input cost compared with the price of EVA membrane.Current filling membranes vary due to filling levels and variable product quality, and cainong will make multiple inspections of each product and choose a regular company for purchase when buying it.

       EVA membrane.The EVA shed films are the currently used in larger number of types of greenhouse plastic films which show a strong light transmission with light transmittance above 92%;With droplet haze, the droplet period is over 4-6 months;They have excellent aging resistance (over 18 months) with excellent retention and dust control.Three layered EVA shed films can be widely used for the production of economical type of non contaminated vegetables such as cucumber, tomato, pepper and bitter melon.The disadvantage is a higher price price price, which differs according to the thickness specifications, with the current market prices being: 0.08 mm in general is 2.05-2.1 RMB / m2, and 0.09 mm in general is 2.15-2.2 RMB / m2.

       In addition, Po membranes are also a new class of films developed in recent years, which are functional polyolefin agrofilms produced by using polyolefins, for their light transmission, continuous fogging, flowability, heat retention, etc., among shed films, cost-effective and a promising class of films to be promoted and at the same time influenced by many brands of Po membrane production technology currently used in China,Many companies produce Po membranes that are of poor quality, and cainong also needs to admit well-known brands when buying them.