Production line of PA6 / PE alloy blend multilayer coextrusion cast film
DATE：2021/7/7 8:42:01 / READ： / SOURCE：This station
Production line of PA6 / PE alloy blend multilayer coextrusion cast film
PA6 and PE blends are very important alloys. Compared with pure PA6, it has the advantages of small water absorption, good dimensional stability, good dry and low temperature impact properties, and wide application. The main varieties are PA6 / LDPE and PA6 / HDPE. In terms of structure, PA6 / LDPE can be divided into two types: ordinary distribution structure and layered structure. As a new generation of packaging materials, layered alloy has a broad market prospect. Multi layer co extrusion casting film production line www.handern.comPA6 / LDPE LDPE in thermoplastic has low density, easy processing, good mechanical properties, water resistance, chemical corrosion resistance, good dielectric properties, and low price. But LDPE has low strength, so it can not meet the requirements of heat resistance, creep resistance and dimensional stability when used as industrial parts. LDPE and engineering plastics PA6 can be blended to produce materials meeting different requirements. There are structural differences between LDPE and PA6, and they are incompatible. The properties of LDPE / PA6 blends are poor. In order to improve the compatibility between LDPE and PA6, LDPE is often grafted. It can be seen from table 4-19 that the impact strength of PA6 / ldpe-g-mah blend is significantly higher than that of LDPE / PA6 blend. After grafting modification, the fluidity of LDPE / PA6 blends will change, which affects the control of material processing. The non Newtonian property of ldpe-g-mah / PA6 blends is stronger than that of LDPE / PA6 blends. In a certain range of shear rate, the melt viscosity of LDPE gmah / PA6 blends is higher than that of LDPE / PA6 blends. Multi layer co extrusion casting film production line www.handern.com
PA6 / HDPE HDPE has the characteristics of non-toxic, low price, light weight, moisture resistance, chemical stability, low temperature toughness and good processability. PA6 is an engineering plastic with high strength, high heat resistance and good barrier to non-polar solvents. PA6 was used as barrier modification component to improve the barrier property by alloying. A kind of polymer alloy material with good barrier property was prepared. It can not only reduce the cost, but also improve the penetration resistance of HDPE to organic solvents. It has high practical value and can be used in the packaging of pesticide, medicine, gasoline and other leaky articles. In order to mix two or more kinds of polymers and obtain stable alloy materials, one of the important conditions is that the solubility parameter (8) of the polymer to be blended should be close, and the difference should be less than 1, usually less than 0.2. The difference between HDPE and PA6 is about 5. Obviously, it is difficult to obtain HDPE / PA6 alloy with good properties only by simple blending of two polymers. Therefore, the third component is needed to enhance the compatibility of HDPE and PA6, and the third component is compatibilizer. It can be seen from figure 4-6 that the addition of compatibilizer has a very obvious effect on improving the mechanical properties of HDPE / PA6 blends. All the performances have been improved in varying degrees. With the increase of compatibilizer content, the tensile strength and elongation at break increase gradually, and the notched impact strength first increases and then decreases, with a peak value. This may be due to the excessive amount of compatibilizer, the formation of free phase of compatibilizer dispersed in the system, and the compatibilizer itself is not an elastomer, which has no contribution to the absorption of impact energy, so the impact strength decreases. Multi layer co extrusion casting film production line www.handern.com
PA6 is a polar polymer and HDPE is a non-polar polymer. Due to the great differences in molecular polarity, chain structure and viscoelasticity between PA6 and HDPE, serious phase separation will occur due to the poor force between the blends and smooth phase interface, resulting in coarse particles of dispersed phase, which makes it difficult to form lamellar dispersion during mixing. Therefore, in order to improve the compatibility of HDPE / PA6 and make layered blending possible, it is necessary to improve the compatibility of HDPE / PA6 blends, so compatibilizer must be added. Compatibilizer acts as a high molecular weight surfactant, which can aggregate at the interface of incompatible two phases, reduce the interfacial tension and the size of dispersed phase. It can be seen from the SEM photos in Fig. 4-7 that the addition of compatibilizer will lead to the change of the micro morphology of PA6 / HDPE Blend System. With the increase of compatibilizer content, the particles of PA6 are smaller and more uniform. And there are more filaments in the cavity. This shows that the interaction between the dispersed phase and the matrix phase is becoming stronger and stronger, which is the fundamental reason for the obvious improvement of mechanical properties. Multi layer co extrusion casting film production line www.handern.com
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