Regenerative PET has a great time in the field of plastic woven products!
Regenerative PET has a great time in the field of plastic woven products!
Plastic woven products are important categories of plastic products in China, and our country has become a major manufacturer, consumer and exporter of plastic products. In recent years, the annual output of plastic woven products has increased by more than 20%, and the new national standard of plastic woven bag has been approved and implemented. New gb principle is the principle of lightweight packaging, cancel the requirement for bag is heavy, the assessment of the strength of the bag as the main index, namely whether the bag size weight, as long as can meet the strength indicators. Therefore, the competition in the future plastic weaving products market will be dominated by light quality, high intensity and low price. Source is rich, the price is relatively cheap, than strength is far higher than that of polypropylene PET begin to enter people's horizons, coupled with the excellent properties of PET has many PP don't have, so a PET as the main raw material to produce products in a new era of plastic braided stride was coming to us. As the source of the advantages of raw materials, PET can produce millions of tons of PET bottles. Than the strength of the PP is higher than that in PET bottle flakes as a new material, the density of PET is 50% higher than the PP, but the tensile strength is all together more than doubling of PP, when used in tensile test sample that is to say, its than strength values are similar. After the use of the PET bottle, the material performance of the PET can still reach the new material level after the proper recycling process, while the polypropylene can be degraded significantly and cannot be repaired. The PET bottle should be higher than the strength of the PP with recycled material. In the optimal price based on oil as the main raw material of synthetic resin, the PP price is relatively cheap, but still with international oil prices soaring and long-term in high, and PET bottle flakes as more and more, for short fiber market saturation, prices haven't changed much over the years, it was worth only 50 to 60% of the PP. Good aging resistance of PP plastic woven bags of one of the biggest drawback is not resistant to ageing, do not add antioxidant and light stabilizer PP plastic woven products quickly in the sun pulverization, and polyester can still keep good after a few months Good low temperature resistance of PP plastic woven bags of another big problem is brittle at low temperatures, and PET brittle temperature is very low, even in the coldest days of winter, also can packing in good condition, not burst. The high transmittance can be seen from the polyester bottle, and the non-crystalline PET is completely transparent, which is very important for the packaging of certain items. Appearance is quite rich, beautiful and is helpful for filling Weaving without splitting wire PP in stretch orientation, large molecules along the direction of pull a linear arrangement, perpendicular to the direction of pull only very weak molecular inter-atomic forces, van der Waals force, so under the effect of braiding machine tension, prone to splitting phenomenon, especially when have overstretch phenomenon is more likely to occur. The molecular structure of PET determines that the vertical force has strong intermolecular force in the direction of vertical force, so it is not possible to have a splitting phenomenon during weaving. Excellent creep resistance of PP plastic woven products will happen under the action of external force do not reply to the permanent deformation of the creep, especially in the larger or long time under external force, force and PET plastic woven products can almost like metal materials under external force is not permanent do not reply to the size of the change. This point is very important for the bag belt. Other PET materials have many advantages: fatigue resistance, abrasion resistance, foldability, recyclability, environmental protection, sanitation, etc., can be used in the application of plastic products. The technical difficulties of making woven products with PET bottles and key current production techniques and equipment for making woven products with PET bottles have been perfected. Look from the experience of research and development enterprise, its main technical key has the following several aspects: the PET melt viscosity is low, cannot leave a mouth like PP, stretch film die after water film directly, but must stretch film on the cooling drum, indirect cooling film. Therefore, the production of PP plastic-woven wire drawing machine can not be used in PET bottle. The PET bottle must be fully and thoroughly dry, so that the water content of the PET bottle should reach 0.03%. The temperature and stretch ratio of the PET bottle is different than that of PP, and only the flat wire with the appropriate drawing ratio has the ideal tensile load. The thin thickness of PET flat wire can and must be smaller than PP, which can have competitive advantage in price. Has yet to solve the problem of the applicable filler masterbatch for PET processing, and solve the problem of the function of the PET excess, adding the right amount of minerals such as calcium carbonate powder materials for granted, especially for plastic woven bags of opaque, more need to add filler masterbatch or color masterbatch. The surface of the plastic woven bag made of PET bottle is too slippery, and the surface friction coefficient should be improved by modification. At present, the plastic woven bag made of PET bottle has not yet been properly coated, and its peeling strength is too low. It can be used as the melting and extrusion of PET bottle wire drawing system, and it is required to be strict in the drying of PET bottles. Usually used in hot air drying equipment not only high energy consumption, and it is hard to dry thoroughly, once time is long, can make the material yellowing, and if not immediately use after drying, quickly absorb moisture in the surrounding environment, 30 minutes the water absorbing capacity can reach 500 PPM (0.05%), balanced bibulous rate can reach 0.4%, the moisture content of the PET material can't be directly using the melting process. Water in PET material form is divided into the adsorption and associating and water, the former can remove under 120 ℃, and associating with water would remove above 140 ℃
