Forming method of EVA (Ethylene Vinyl Acetate) foaming object and device thereof

Abstract

The invention relates to a forming method of an EVA (Ethylene Vinyl Acetate) foaming object and a device thereof. The method comprises the following steps of: placing a moulding EVA foaming primary blank, a finished primary mould and a cooling and sizing mould into the same pressure control main chamber the pressure of which can be controlled; particularly separating out a first pressure control secondary chamber and a second pressure control secondary chamber which are respectively independent in the pressure control main chamber; and respectively accommodating the moulds in the pressure control secondary chambers so as to control the pressure values of respective environment of both the moulds via the pressure control secondary chambers and achieve the effects of flexible use, energy saving and labor hour shortening.

Description

technical field [0001] The invention relates to a polymer processing technology, in particular to a molding method of EVA foam and its device. Background technique [0002] In order to improve the many deficiencies derived from the traditional two-stage process of EVA foam molding, a one-stage process is disclosed in the Chinese Patent No. 03137138.8 and No. 03263374.2, which mainly uses the traditional two-stage process respectively. The embryo mold and the shaping mold are placed in the same pressure chamber. By controlling the internal pressure of the pressure chamber, the EVA foam can pass through the high-pressure environment of the pressure chamber during the process of transferring from the embryo mold to the shaping mold. To prevent its volume from expanding beyond the size of the cavity of the shaping mold to be filled, after the EVA foam is properly filled into the cavity of the shaping mold, the pressure chamber is decompressed to a normal environment of atmospher...

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Problems solved by technology

[0003] The above-mentioned prior patent is inherently practical, but, as far as the requirements of the EVA foam manufacturing process are concerned, the method of controlling through a single pressure chamber is not ideal. Specifically, when molding the EVA embryo with the embryo mold, due to It is necessary to completely remove the gas in the mold chamber for containing the EVA raw material, so as not to affect the molding of the EVA embryo. In this previous stage, the injection and foaming process must be carried out in a vacuum environment; moreover, The EVA foam made by the injection foaming process of the previous stage needs to be cooled and shaped in the latter stage, and the cooling and shaping procedure is carried out through a shaping mold with a cooling effect, that is, in the latter stage , the EVA foam that is still in a high temperature state is filled into the finished mold chamber in the shaping mold, and then cooled and molded into the corresponding shape and surface texture. At this time, if there is still gas in the finished mold chamber, then It will also occupy the space of the mold chamber, making the shaping of the EVA foam incomplete and affecting the quality of the finished product

[0004] Of course, in the implementation of this patent, the pressure control of the pressure chamber can also be used to meet the needs of the upper opening process, but unfortunately, even if it is done in this way, because the overall space of the pressure chamber is too large, The procedure of repeatedly pressurizing and vacuuming will generate excessive waste of energy and time, which is not an ideal method

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