Application of plastic sheeting
In plastics most important areas of agricultural plastic light stabilizers, such as agricultural films, film, film fodder, farming film, plastic irrigation pipe, plastic water-saving equipment. Chinese agricultural film production in the world, is the sum of all other countries, 1.6 times the size of the country has a scale ranging from plastic sheeting, more than 1,000 manufacturers, production capacity of more than 2 million t of which the annual production capacity of more than tons about s0 home, its production capacity and production account for s0% a country's annual consumption of plastic sheeting of the national total has reached 1.2 million t, of which 550 000 film a, mulching and accumulated more than 2.2 million acres; Yong membrane annual consumption has reached 650,000 tons, covering an area of 2,500 acres films. In agricultural plastic and agricultural films, the largest consumer of light stabilizers are agricultural films, consumer spending accounts for about total consumption of agricultural films light stabilizer 40%.
1970s began to use our HALS light stabilizer system aging PVC films, mainly GW-540 system, and found as much light stabilizing role benzophenone UV Absorbers (see Table 3-6) e 20 1980 China's use of GW-54. Anti-aging system and nickel complexes consisting of quenching agent 2002 LDPE films significantly increased anti-aging properties, the effective use during the hot season skeleton films at no breakage. Such as adding. . 4% GW-540 and. .1 00 / a 2002 of LDPE / EVA layer composite films thickness. . 12mm, after three months of continuous coverage with favorable results (see Table 3-7). Before the opening of the films in the main LDPE film, PVC films applied only in the northeastern Jilin Province and other areas.
Adding rare earth elements in the films substrate compound light conversion agent, so that the plastic sheeting regulate light quality, the conversion of light effects, such as the ultraviolet light into visible light to increase the photosynthesis of plants, achieve the purpose of increasing production. Such conversion film has been developed, based formulation. Film tune the spectral selectivity, for different crops require different quality of light, choose colored films to inhibit or increase the intensity of certain light waves, such as the purple membrane of leek and Toon yield favorable, pro-green film suitable for growing ginseng, silver films can play shading, and ground temperature lower Pengwen role for summer fruits and flowers planted, the film required more pro add light stabilizers.
Anti-aging functions of the various types of film are required to join the pro-light stabilizers, and must be added a sufficient number of efficient and high-quality light stabilizer, it may hold the film "longevity", however this is only the films "longevity" prerequisite one. When there is a sudden aging films produced ahead of aging damage, the so-called "bursting" The reason: There is no choice of high strength and resistance to aging base resin films, some companies use into n degradable resin or resin production switching process the transition material blown films, resins excessive levels of metal ions, which will greatly affect the life of the films. Chinese agricultural plastic Applied Technology Institute after more than ten years of tests concluded that anti-aging base resin films meet the following conditions: ① high molecular weight, narrow molecular weight distribution; ② branched low number of double bonds; ③ contained springbok group, peroxides, free radicals, metal ion content as low as possible; ④ same resin low crystallinity as well; ⑤ resin should be added antioxidants, but opening agents, slip agents with less or without plus as well. Furthermore, other additives match to be reasonable, such as flow drops acid value and lower carbon values. Films process will affect its anti-aging properties: first of all to be made masterbatch additives and carriers, and then uniformly mixed with the base resin film to protect the uniform distribution of additives and resins; extruder temperature, speed, wind speed, winding speed, blow-up ratio, the best and the draft ratio should remain stable and only requires sufficient thickness of the films, but also limit the thickness deviation and the mean deviation of the thickness of the films is also crucial life films Finally, farmers' use of links, such as the tightness of the films, the skeleton is smooth and corrosion, types of pesticides and spraying frequency, location, should properly, will lead to "overwhelmed." So add a light stabilizer for agricultural films is "longevity" indispensable prerequisite, but not the only condition.
China in 2010 will increase the area of Horticulture 3800 acres, the annual demand for anti-aging functional films to around 300 000 t, accounting for annual sales of 40 films, the films will light stabilizers annual demand of about 1000t addition, mulch the cultivation area will be expanded to cover 3.1 million hectares, mulch annual consumption will increase to about 780 000 t; animal husbandry, aquaculture special greenhouses area expanded to about 150 acres, ammoniated Qinghai-Tibet, stretch film demand will reach 300 000 t; other agricultural plastic also will significantly increase the demand for agricultural plastics will continue to be a light stabilizer largest consumer market in 2004 China synthetic resin 17.91 million t, into the daily amount of 21.31 million t, apparent consumption of 38.13 million t, than in Germany, N of the sum of consumption in South Korea and France are also many, is about 70% of the United States, consumption of synthetic resins and plastics production are ranked second in the world, its annual growth rate is higher than the rate of China's GDP. Agricultural demand in 2005 is expected to 3,000,004 new electronic appliances require modified polypropylene, Af3S resin plastic and alloy 26. Million t, 1.8 million plastic building t, automotive plastics over SO million t, these areas light stabilizer consumption will be greatly increased.