Development of foam molding technology
DATE：2021/10/25 9:10:47 / READ： / SOURCE：This station
Development of foam molding technology
With the world oil and plastic prices rising year by year, foam plastics have been expanded to be applied to various plastic processing industries, because foam plastics can save as much as 25% to 30% of plastic raw materials. On the other hand, the sound insulation, heat insulation, cushioning and other characteristics of foam plastics are also important factors that promote their increasingly widespread use. The expansion of foam applications has further promoted the development of foam molding technology. Summarizing the relatively mature new foam molding technology at present, it can be roughly introduced as follows.
1. Micro cellular plastic
Microcellular foam technology has actually been applied in the packaging field for nearly 10 years. However, it has only been vigorously developed as a hot technology in the plastics industry in recent years. The diameter of the usual closed-cell foam is about 150-250m, and the diameter of the micro-bubble closed-cell foam is about 50m or less. The corresponding density of the micro foam is 0.035-0.gcm. This technology has been developed by MT (Massachusetts Institute of Technology), Dupont (Society State), Boeing (Boeing), dk (Da), Lockheed (Lockheed), etc. . Now Trexel in the United States holds the right to use and develop this technology. According to the English word for Microcellular (Microcellular),
T=The company names its products MC. At present, the commercial product that has been mass-produced is the extruded sheet of microfoam. In the processing of styrene extruded sheet in Muc case, non-flammable inert gas, such as hydrogen or carbon dioxide gas, is directly injected into the extruded plastic melt. The technical key here is that the injected passion gas must first be pressurized and compressed to a supercritical state. In this supercritical state, the gas already has liquid-like solubility. Such gas can be in the plastic melt and thus result in a very fine bubble core. Once such a mixture of plastic melt and gas is extruded from the extrusion die and the pressure is released to expand, very small and dense microbubbles can be obtained. Because the gas has solubility before injection, the bubbles can be evenly distributed throughout the extruded melt, so that the bubbles of the micro-bubble structure foam are evenly distributed, and the performance of the part can be basically isotropic. This is one of the important factors that greatly improve the physical and mechanical properties of the microbubble structure of the polystyrene board. Comparison of physical performance between MuCl styrene board and ordinary polystyrene foam board of the same size. It can be seen from the figure that when the density is 0.03g/cm3, the performance of the two plates is the same. However, as the density increases, the physical and mechanical properties of the two types of plates have obviously different trends. When the density of the two types of plates are also doubled, the strength of Mucell plates is more than double that of ordinary plates.
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