Agricultural films with raw materials mainly include PE, PVC, EVA, and PET and ETFE abroad. Mulch is mainly composed of LLDPE, in order to increase transparency and reduce the load, and blending with a small amount of LDPE.
River according to the features, choose the right resin, resistance to aging of agricultural film, heat preservation, light transmittance, dripping and other technical indicators play an important role.
On the basic requirements of raw materials:
1. Good optical performance, high light transmittance. Low haze;
2. Good glossiness;
3. Good aging resistance;
4. Good physical and mechanical properties;
5. Good insulation performance, the high infrared resistance through rate;
6. And functional additives have good compatibility;
7. Good forming performance;
8. The optimal price.
Choose cover material according to conditions of use. In fact a kind of raw material is difficult to give attention to two or morethings arrives above all performance, in the application need to choose according to the conditions of use. For example: ordinary, energy-saving greenhouse cover material use PVC, EVA, big inter-cooled tent with low VA content of EVA, PE do cover material; Basic all use PE do cover material and small tunnel.
Agricultural plastic film base resin raw materials
1. PE
PE concrete generally divided into LDPE, LLDPE, HDPE. Widely used in agricultural film are LDPE, LLDPE. In practical application is according to the specific way of using different blending proportion.
(1) the LDPE, LDPE and LLDPE, forming good processability, soft products, transparency, good low temperature resistance.
1. With LDPE resin films production practice shows that PE films production and longevity should first choose MFR = 0.3 ~ 0.4 g / 10 min river special level or heavy packaging material. Homebred brand used more mature with yanshan petrochemical LD163, LD165, 2 f0. 4 a, qilu petrochemical 2100 tn00 etc, in the United States imports of exxon FB3003 2100 tn00 LD165, Holland, Qatar, etc. Multi-functional films appropriate chooses MFR PE = 0.3 ~ 0.8 g / 10 min river level materials, applied in the industry have a more mature Beijing YanHua LD150 exxon LD150, qilu petrochemical, 2101, the United States. In the production of small tunnel, daqing 18 d (MFR = 1.5 g / 10 min), Beijing YanHua LD100 (MFR = 2. 0 g / 10 min), Shanghai petrochemical N150 (MFR = 1.5 g/l0min) is widely used.
2. Use LDPE mulch production has been used in film production LLDPE as the main raw material, to reduce the processing load and improve transparency, some enterprises to join a small amount of LDPE,. Can use MFR = 1.5 ~ 2.0 g / 10 min resin. Beijing YanHua LD100 application effect is good.
(2) LLDPE: LLDPE linear main chain, compared with LDPE, narrow molecular weight distribution, short branched chain. Therefore decided to good mechanical properties, ageing resistance properties of LLDPE in LDPE, this characteristic on the thin film was particularly outstanding, but its processing performance, optical performance is LDPE.
1. Wide PE films with LLDPE production feature films, is proved to be preferable MFR = 0.8 ~ 1.0 g / 10 min river level materials, application of more mature have a domestic brand in tianjin petrochemical, yangzi petrochemical, 1081, 9085 imported brands exxon 1001, 118 n in Saudi Arabia, the United States dow 1001, etc. Production of small tunnel can choose MFR = 0.8 ~ 2.0 g / 10 min film grade LLDPE, used more mature domestic 7042, 0209, aa, import brands such as exxon 1002, Saudi Arabia, 218.
2. The film with LLDPE domestic enterprises producing film usually choose MFR = 0.8 ~ 2.0 g / 10 min LLDPE film production. Homebred brand 7042, 9020, l082 mature Wells such as a large number of applications. The same brand but different manufacturers have different in the process of using, some use good, some easy appear crystal points. Have blown film membrane bubble, unstable, easy to have a falling knife. Imported brands have Canada 0218 d, 1002, Saudi Arabia, 218 w and exxon, better application.
(3) mLLDPE international in recent years on the new development of metallocene linear low density polyethylene with its excellent optical performance and outstanding mechanical property has become a production of light-weight, high strength, high photosynthetic efficiency one of basic raw materials of choice for films, application of more mature with exxon ECD342/341, Japan's mitsui SP1520, etc.
2. EVA
General EVA agricultural application in solar greenhouse. More used in production of multilayer composite extrusion blown film technology. In three layer compound, for example, inner button (tent) use the VA content 5% ~ 5%, MFR = 0.3 ~ 1.0 g/l0min; Middle-level using VA content 9% ~ 9%, MFR = 0.30 ~ 1.0 g/l0min; The outer button (tent) choose LDPE LLDPE ten (or mLLDPE) blend as a skeleton layer. Application of more mature Beijing organic 5/0.3, 9/0.7, 5/0.3, Korea EF443 EF321, Formosa plastics, 7140, 7 l30, etc.
3. PVC
PVC is the amorphous polymer polarity. Has excellent thermal insulation properties, optical properties, and can and flow agent and antifoggant picked good miscibility, therefore energy-saving sunlight greenhouse in the north has been widely applied, especially on the cucumber such as high temperature crops more EVA, PE has obvious advantages. In addition, domestic during the "tenth five-year plan, due to the international oil prices and rising domestic demand for PVC, PVC production capacity to 2005 in our country
Capacity has reached 9.3 million tons, and the actual output of 630 tons, therefore the domestic present a supply glut, price is much lower than the price of PE resin.
At present, the domestic use rolling method to produce soft PVC agricultural film. Usually choose SG - 2, SG - 3 type universal PVC resin suspension method, add the right amount of plasticizer, stabilizer, ageing resistance, flow drops made PVC calender functions such as agricultural film. Agricultural film and PE, PVC, EVA as multicomponent materials, processing performance, products properties not only with the molecular structure of the PVC resin, particle shape, particle size, and is related with the nature of additive system components, and add the quantity.
Domestic PVC resin has oil cracking and calcium carbide method (acetylene method) two kinds of raw material source, the current two ways of 50% each. Low price of PVC resin by calcium carbide method, but the method of the oil production of PVC "fish eye", impurities (black yellow dots), broad molecular weight distribution, processing performance is poor. Used better have qilu petrochemical, Shanghai chlor-alkali corresponding number.
