Linear low density polyethylene

DATE：2022/7/14 8:37:06 / READ： / SOURCE：This station

Linear low density polyethylene

Linear low density polyethylene (LLDPE) is a copolymer of ethylene and a small amount of a olefins (such as 1 butene, 1-hexene, 1-octene, etc.) polymerized under high pressure or low pressure in the presence of catalyst. PVB film production equipment www.handern com
The appearance of linear low-density polyethylene is similar to that of ordinary low-density polyethylene; The density, crystallinity and melting point of linear low-density polyethylene are lower than that of high-density polyethylene, with crystallinity of 50% - 55%, slightly higher than that of low-density polyethylene, but much lower than that of high-density polyethylene; The melting point of linear low-density polyethylene is slightly higher than that of low-density polyethylene (generally 10~15 ℃), but the temperature range of melting point is very small; Linear LDPE has better mechanical properties than ordinary LDPE, such as tear strength, tensile strength, impact resistance, environmental cracking resistance and creep resistance; Electrical insulation performance is also better than low-density polyethylene; The film made of linear low-density polyethylene is soft and heat-resistant. It has high tear strength and heat sealing strength, but the transparency and gloss of the film are poor. See table 2-15 for the properties of linear low density polyethylene with different densities. See table 2-16 for the comparison of density and crystallinity of linear low density polyethylene (ll DPE) with LDPE and HDPE. See table 2-17 for the performance comparison of linear low density polyethylene (LLDPE) with LDPE and HDPE. See table 2-18 for the comparison of processing characteristics between linear low density polyethylene (LLDPE) and LDPE and HDPE. Compared with LDPE, it is difficult to compare the tensile strength of secondary elongation with HDPE, and the turbidity processability is poor. Compared with LDPE, it is better and easier to compare with Hun. The impact strength is better and similar to the environmental stress cracking resistance. The transparency and gloss are poor and better, the heat resistance is high, 15 ℃ is low, the melt strength is low and low, the initial property is high, the melting point range is low, and the burnability is small and similar. PVB film production equipment www.handern com
Lldpeldpe and HDPE processing characteristics comparison: LDPE LLDPE HDPE of the project, film blow molding is the easiest, generally the most difficult, injection molding is soft and rigid, warpage is small, rigidity is good, pipe extrusion is soft, circumferential stress resistance is good, rigidity is good, cable extrusion speed is fast, heat resistance, environmental stress cracking resistance is good, heat resistance is good, crosslinkable, hollow molding billet strength is good, billet strength is poor, rigidity is good, Rotary molding has good fluidity, the highest fluidity is difficult to flow, powder coating needs higher temperature for low-temperature softening, the suitable conditions are narrow, the extrusion coating necking phenomenon is small, the necking phenomenon is large, the suitable conditions are narrow, and the crosslinking foaming performance is easy to control, difficult to control, and the performance is easy to control. PVB film production equipment www.handern com
Quality standard: the quality standard requirements of linear low density polyethylene resin are specified in gb/t 15182, see table 2-19.
Molding method and application: linear low-density polyethylene resin is generally used for injection molding plastic products by injection molding machine. The modified linear low-density polyethylene can be molded into plastic products by blow molding, injection, roll molding, extrusion and other methods. The extruder can be used to extrude and shape pipes, wire and cable sheaths, extrude and blow various thickness films, and shape hollow products. Injection molding machine is used to inject various industrial accessories, airtight container covers, auto parts and industrial containers. It is processed into large containers such as pesticide and chemical containers and tank cars by rotary molding method. Cast film can also be formed by casting method, which is used for lamination, printing and construction films. PVB film production equipment www.handern com
The density of medium density polyethylene is 0.926~0.940g/cm, and its molecular structure is between low density polyethylene and high density polyethylene. Medium density polyethylene can be produced by several methods, such as mixing high-density polyethylene and low-density polyethylene in a certain proportion; With the production process of high-density polyethylene, medium density polyethylene can be obtained by adjusting the dosage of comonomer 1-butene to make the density of polymerized products within the range of medium density. The abbreviation code of medium density polyethylene is MDPE.
The crystallinity of medium density polyethylene is 70% - 75%. The properties of medium density polyethylene are the same as those of low-density polyethylene and high-density polyethylene, and it has excellent stress cracking resistance, rigidity and heat resistance, which LDPE and HDPE do not have. The performance parameter values of medium density polyethylene are listed in table 2-1, which can be used for reference. At present, there is no national standard for the quality of medium density polyethylene resin. Product quality standards of several medium density polyethylene resin manufacturers in China. Rotary molding, with good rotational molding.
Processing method and application performance, high impact resistance, suitable for making various stretch and environmental stress cracking resistance, pipe material, good pulling small and medium-sized toys, storage tanks, garbage cans, good processability, suitable for making all kinds of storage tanks, and also can be used as admixture utility pipes. PVB film production equipment www.handern com

Author：admin

---