Molded product of a polypropylene-based resin expanded particle and method for producing the same

Abstract

The invention relates to a molded product of a polypropylene-based resin expanded particle and a method for producing the same. The object of the invention is to provide a molded product of a polypropylene-based resin expanded particle with a low expansion ratio having excellent fusibility between expanded particles mutually, small density difference between a surface part and an inner part of the molded product, better mechanical properties, such as compressive strength, compared with a conventional one, and also excellent appearance. In an in-mold molding method with the polypropylene-based resin expanded particle, the expanded particle has apparent density of 60-450 g / L, the welding rate of the polypropylene-based resin expanded particle is above 50%, the ratio between the apparent density of the expanded particle molded body to the inner density of the molded body is 1-2 and the molded product of the polypropylene-based resin expanded particle is preferably molded when satisfying the special conditions.

Description

technical field [0001] The present invention relates to a polypropylene resin expanded particle molded body and a manufacturing method thereof, in particular to a high-density polypropylene resin expanded particle molded body with a small density difference between the surface layer and the inside of the expanded particle molded body, and to a high-density polypropylene resin expanded particle molded body. When in-mold-molding expanded polypropylene resin particles having a higher density, the expanded-bead molded body can be obtained at a molding temperature lower than conventional in-mold molding temperatures. Background technique [0002] Polypropylene resin, because of its excellent properties such as mechanical strength, heat resistance, processability, incineration, and recyclability, has been expanding its application fields. Similarly, the polypropylene resin foamed particle molded body formed by in-molding polypropylene resin foamed particles will not lose the excel...

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Problems solved by technology

[0006] In this case, if the water vapor pressure is increased, the heating temperature will also become higher, so there is a problem that the cooling time at the time of in-mold molding becomes longer and the productivity decreases.

In addition, since the obtained expanded bead molded body is molded in-mold using saturated water vapor with a high water vapor pressure, the air cells in the surface layer of the expanded bead molded body are broken and densified, and the obtained expanded bead molded body There is a density difference between the inside and the surface layer, and there are problems of insufficient mechanical strength such as compressive properties

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