PCTFE film production line modified by blending polyethylene and nylon
DATE：2021/7/20 8:37:45 / READ： / SOURCE：This station
PCTFE film production line modified by blending polyethylene and nylon
HDPE has the characteristics of abundant sources, low price, convenient processing, and excellent impact resistance, corrosion resistance, etc. the containers blown by HDPE are widely used for packaging daily necessities and industrial chemicals. However, HDPE has poor barrier to hydrocarbons and organic solvents, which limits its application in the field of packaging containers to replace glass and metal containers (such as packaging pesticides, paint thinner, industrial cleaner and various fuels). At the same time, leakage will inevitably cause environmental pollution, insecurity and health hazards. The methods to improve the barrier properties include fluorination or sulfonation of the inner surface of HDPE bottle, multi-layer extrusion and layer blending blow molding. Due to the problems of environment and investment, fluorination or sulfonation of inner surface is still not popular. For multi-layer extrusion blow molding, due to the strict equipment requirements and not suitable for complex shape products, the application is also limited. Different from multi-layer extrusion blow molding technology and fluorination or sulfonation treatment technology of inner surface, layered blending technology can improve the barrier performance of containers by forming a layered structure containing a small amount of discontinuous and cross distributed barrier resin in HDPE matrix, which has the advantages of easy processing and less investment. PA is a kind of resin with high barrier property to hydrocarbons and organic solvents. Therefore, HDPE / PA layered blend with only a small amount of PA can have the comprehensive properties and excellent barrier properties of HDPE and Pa. its blow molded container can be widely used for packaging pesticides, paint thinners, industrial cleaners and various fuels, which has great social and economic benefits. PCTFE film production line www.handern.comPA6 melt strength is low, it is difficult to blow molding directly, and can be blended with HDPE layer by layer. The layered blending technology was first announced by DuPont in 1983. Due to its relatively simple process and no pollution to the environment, the recycled materials in the production process can be reused, and the barrier properties of the composites are excellent, it has become a research hotspot in the field of materials in the world, Both academic and industrial circles are actively researching and developing this new functional material. The layered blending technology is to realize the layered distribution of barrier resin in HDPE matrix resin by selecting the blending components with appropriate viscoelastic ratio, improving the thermodynamic incompatibility between the two phases, and adopting appropriate processing equipment and corresponding molding processing conditions. PCTFE film production line www.handern.com
The temperature control of preparing barrier HDPE / PA6 blends is very important, because the temperature will affect the viscosity ratio of two phases. It is generally considered that the range of 0.5 ~ 1.5 is suitable. The closer the droplet is to 1, the easier it is to deform and break, and the easier it is to form layered structure. Under the same conditions as other molding conditions, the viscosity of dispersed phase and continuous phase will change with the change of temperature, and the deformation ability of dispersed phase will also change. Under the condition of ensuring the full melting of PA6, another main factor favorable to the deformation of droplets is the shear field, which is mainly reflected in the shear mixing process caused by the rotation of the screw. Therefore, the appropriate screw speed is also an important process condition for the formation of layered blending. With the increase of screw speed, the layered structure will be broken due to the increase of shear strength, and finally tend to disappear. The shear action of screw not only makes the blends melt and mix, but also controls the size of the dispersed phase before entering the layered region. In order to obtain the layered morphology of the dispersed phase, it is necessary to maintain a low shear rate in the molten region to ensure that the bulk dispersed phase is fully biaxially stretched in the layered region. Therefore, lower screw speed is conducive to the formation of layered structure. PCTFE film production line www.handern.com
Due to the layered distribution of dispersed phase PA6 in HDPE matrix resin and the zigzag channels between layers, the penetration time of solvent molecules is greatly prolonged, and the permeability of the blend blow molding bottle is significantly decreased (see table 34 for test results). It can be seen from table 3-4 that the barrier performance of barrier bottle for common hydrocarbon solvents has been greatly improved compared with that of pure HDPE hollow blow molding bottle. It depends on the formation of layered structure. The results show that the ultrasonic wave has a good effect on the extrusion of PA6 / HDPE (80 / 20) blends. The introduction of ultrasound can improve the mechanical properties of the blends, and affect the morphology of the blends and the crystallization properties of the two components. It can greatly reduce the melt viscosity of the polymer, effectively improve the processability of the polymer and the apparent quality of the extrudate, and effectively improve the compatibility of PA / PE system, so as to make the lamellar distribution and barrier property of PA6 better. PCTFE film production line www.handern.com
Author：admin