A method for demolding continuous extruded in-mold skinned pp foamed sheets

Abstract

The invention relates to a demolding method for a crust PP foamed sheet in a continuous extrusion die. The demolding method comprises the following steps: an extruded melt is adjusted by a high temperature channel to keep the temperature of the contact surface of the melt and an enhanced crystallization foaming device be equal to or more than 220 DEG C, the surface of the melt rapidly crusts afterthe melt reaches heat insulation holes due to the internal temperature, being 80 DEG C, of the enhanced crystallization foaming device, the enhanced crystallization foaming devices starts from the first level, cold water is introduced to make the contact surface of the device and the melt less than the crystallization temperature of PP in order to make the surface of the PP melt crystallize and crust, the surface of the PP melt is in contact with the upper surface and the lower surface of a differential crusting device to make the melt rapidly crystallized and cure pores, and a sheet which ispre-sized after conversion and crystallization of the melt is continuously defoamed and demolded under a constant pressure, leaves the differential crusting device, is continuously demolded, enters afixing die, and is fixed to obtain a qualified product. The method effectively reduce the vacuum adsorption force and other demolding resistances, facilitates the strength enhancement of a PP crystallized crusted layer, converts extrusion thrust into demolding thrust, and achieves the smooth realization of continuous crystallizing, crushing, extruding and demolding of the PP in a differential enhancement device.

Description

technical field [0001] The invention relates to the technical field of polymer material molding, in particular to a demoulding method for continuously extruding in-mold skinned PP foam boards. Background technique [0002] The demoulding technology of continuous extrusion molded skinned PP foam sheet is one of the key technologies in a new polymer molding method developed by us. Whether the PP foamed sheet can be demoulded smoothly after molding is related to whether it can be produced smoothly. If the demoulding force is large, the pulling force needs to be large, and it is not easy to be stable. If it is easy to fluctuate, it is easy to break the board. The foaming ratio is affected by the tension. Inch affects the size and internal stress of the finished board. Similar to injection molded products, a release agent is required when demoulding, and the mold design needs to be designed with a demoulding slope, etc. Otherwise, the demoulding resistance will cause the product...

AI Technical Summary

Problems solved by technology

Whether the PP foamed sheet can be demoulded smoothly after molding is related to whether it can be produced smoothly. If the demoulding force is large, the pulling force needs to be large, and it is not easy to be stable. If it is easy to fluctuate, it is easy to break the board. The foaming ratio is affected by the tension. Inch affects the size and internal stress of the finished board

Similar to injection molded products, a release agent is required when demolding, and the mold design needs to set the demoulding slope, etc. Otherwise, the demoulding resistance will cause the product to deform and affect the product quality.

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