PVC Although China has the largest production capacity of PVC in the world, but due to the decline of ethylene prices, the import volume of ethylene PVC in 2009 has reached a new record. On the other hand, China's PVC market is always at a low rate of opening. In the first half of 2009, China imported about 1 million 200 thousand tons of polyvinyl chloride (PVC), 1 million tons more than that of 2008. With the rising price of ethylene, the competitive advantage of the Chinese carbide PVC production has emerged. In the second half of 2009, the import of PVC in China declined steadily. According to Chinese customs data, the import volume was only 60646 tons in November. 2013, in the first half of the year, due to many unfavorable factors such as overcapacity and weak downstream demand, the overall performance of PVC industry is not good enough, and enterprises are in a rather difficult position. But PVC foreign trade market performance is great, a number of data compared to the same period in the same period have obvious restorative adjustment. However, insiders pointed out that with the increase of the operation rate of PVC plant in the US, it is expected that China's PVC foreign trade will show a steady growth in imports and a steady decline in export volume. According to the China Chlor Alkali Industry Association statistics, as of the end of June 2013, the domestic PVC (or resin) production capacity of 23 million 920 thousand tons / year. In the first half of 2013, the newly increased capacity of PVC was 860 thousand tons / year, leaving 350 thousand tons / year, a net increase of 510 thousand tons / year. In the export aspect, the cumulative export volume of PVC in China in 1~5 month increased by 152.4% compared with the same period of last year. From the point of view of the flow, the largest export market is India; the number of exports to Russia is slowing down to second. In addition, since the outbreak of the financial crisis, the global market and trade environment have changed a lot. The trade protectionism of various countries is rising, and the trade frictions against Chinese enterprises are increasing significantly. [8] Physical and chemical properties of PVC PVC (polyvinyl chloride) plastic raw material The original color is yellowish semitransparent and glossy. Transparency is better than polyethylene and polypropylene, and worse than polystyrene. With the amount of auxiliaries, it is divided into soft and rigid polyvinyl chloride, soft products are soft and tough, and feel sticky. Hardness of hard products is higher than that of low density polyethylene, but lower than polypropylene, so there will be whitening phenomenon at flexion. Stable; not easily corroded by acid?or?alkali; tolerated to heat. PVC has the advantages of flame-retardant (flame retardant value is more than 40), high chemical resistance (concentrated hydrochloric acid, 90% sulfuric acid, 60% nitric acid and 20% sodium hydroxide), mechanical strength and electrical insulation. The stability of PVC to light and heat is poor. The softening point is 80 C, and it begins to decompose at 130. In the case of non heating stabilizer, PVC begins to decompose at 100 C, and the decomposition of PVC is faster than 130. The thermal decomposition of hydrogen chloride gas, (hydrogen chloride gas is a toxic gas) to make it discoloration, from white to yellow to red to brown to black. The ultraviolet and oxygen in the sun will cause the polyvinyl chloride to be photooxidize and decompose, thus making the PVC flexible and finally embrittlement. It is not difficult to understand why some PVC plastics will turn yellow and crisp for a long time. LCP The compression pressure / holding time is the best appearance and size control for the plastic parts, and the pressure holding time plays an important role. In theory, the holding time is the time needed to solidify the gate. Compared with other engineering plastics, PA46 usually requires only a very short holding time due to its rapid solidification characteristics. It can reduce the sag and hole caused by the volume contraction through the long enough pressure protection stage. However, the pressure protection should not be too high to avoid the stress. One way to determine the correct pressure level is to increase the pressure pressure until the depression is not seen. After the complete cooling, it is cut at the thickest part of the plastic part to check if there is a hole. If necessary, the pressure protection pressure can be increased. One way to determine the holding time is to measure the weight of the plastic part, and then increase the holding time until the constant weight is obtained. A more complex approach is to install sensors in the cavity to determine the exact setting time of the gate. Compared with PA66, PA46 needs only about half of the holding time. This combined with its higher mold temperature can explain why PA46 has a shorter period of time than other engineering plastics. [die temperature / cooling time] because the PA46 curing speed is very fast, so its cooling time is also very short. For this reason, the plasticizing time is usually the determinant of the molding cycle. In theory, the processing process of PA46 can be carried out within a wide range of die temperatures. In order to obtain good dimensional stability and fluidity, the recommended die temperature should be higher than 80 C. In order to reduce the later shrinkage, increase fluidity, improve the strength of weld line and improve toughness and surface quality, the die temperature can be increased to 120 degree C?or?even higher. [open model]PA46 usually does not adhere to the surface of the mold and has good demoulding characteristics. Because of its high crystallinity, PA46 has fast curing and high rigidity at high temperature. So the injection parts of PA46 can be removed at a relatively high temperature, such as 200 C, so that the molding cycle can be shortened. [production stoppage] when the production process is going to stop for a short time, the hopper should be closed, the cylinder will be emptied and the screw is in the front position, and the temperature of the barrel can be maintained. For 1 ~ 2 hours of production stop, the same step should be adopted, but the temperature of the barrel should be reduced to 260 C. When the machine is opened, the new material is used to flush the barrel. For flame-retardant grade, the barrel should be washed with HDPE before the machine is pause. [shutdown / cleaning] the hopper should be emptied at the end of PA46 production, and a high viscosity grade of HDPE is used to flush the barrel. The temperature range of the barrel is reduced to the temperature range of the next polymer to be processed. 1. combustible materials 2. with easy processability and excellent flow performance 3. excellent tensile strength and good adiabatic performance 4. flame retardant; electroplating; heat-resistant; heat-resistant 5. high stiffness keep performance, and show good high temperature resistance to vermicular. 6. stiffness and creep modulus of PPS, PEI and PES due to the same glass enhancement degree 7. it can be used for parts with a thin-walled part to reach 0.1 millimeters without flfei. PA46's main application field connector series, connector, optical cable connector, optical cable connector, USB series Processability PA6 The application of PA6 in daily necessities Asia Pacific International polyamide glass fiber reinforced material has good dimensional stability and low warpage, solderability and paint, easy spraying, ultrasonic welding, material can have good gloss, can be dyed in various colors, in order to meet the requirements for use in industrial products, enhanced polyamide material should meet the following requirements: 1). Combination of strength and durability, excellent rigidity and heat resistance 2) optimize parts design, excellent performance, perfect surface appearance, can be applied to complex structure molding, and help developers design new modeling products. 3). Good processability, excellent fluidity and thermal stability make the material processing conditions more loose, making the injection molded parts miniaturized 4). High thermal stability, free of tin in wave peak soldering with up to 270 degrees 5). A constant electrical property within a wide range of temperature and frequency to ensure safety in the use of equipment. The application of PA6 in the field of automobile Interior and exterior parts Automotive high performance reinforced polyamide composite has excellent weather resistance, good paint performance and excellent performance. In order to meet the requirements of interior and exterior decoration, the polyamide material should have the following requirements. 1). High heat resistance, long term use; 2) the combination of excellent rigidity and toughness; 3). It is able to meet the constant changes in the temperature and humidity, and bear great strain. 4). Excellent dimensional stability, with the effect of warping; 5). It has high surface quality and smooth surface.