JPS61268412A - Integral foam molding - Google Patents

Abstract

PURPOSE:To manufacture an integral foam molded body with no defect such as cavity by a method wherein polyurethane foam stock liquid is sprayed onto the surface at the required portion of a core material and a skin material, both of which are arranged onto mold surfaces and, after that, the stock liquid is expanded. CONSTITUTION:Firstly, soft polyvinyl chloride skin material 7 and glass fiber reinforced acrylonitrile-styrene resin core material 5 are housed in the cavity 4 of a foam mold 1. Secondly, liquid mixture of polyether polyol, crosslinking agent and the like and diphenylmethane-4,4'-diisocyanate are mixed by means of a two-pack type spraying machine 8 in order to be sprayed onto the whole required surface of the skin material 7 with no portion left uncovered. Secondly, both an upper and a lower molds are closed and given heat as desired so as to expand and cure in order to obtain an integral molded part 10 consisting of the skin material 7, polyurethane foam 6 and the core material 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is applied to, for example, automobile interior materials, particularly instrument panel pads, armrests, peeler pads, etc., in which polyurethane foam is used between a skin material and a core material. The present invention relates to an integral foam molding method useful for manufacturing an interposed integral molded article.

(Conventional technology) Instrument panel pads, etc. of automobile interior materials,
Traditionally, integrally molded products in which polyurethane foam is interposed between the skin material and the core material have been used. Conventionally, these integrally molded products are made by first filling and reinforcing AS resin with glass fiber, usually based on the one-shot method. (hereinafter referred to as ASG)
A core material made of polyester, etc. is placed on the upper mold surface of the pad mold, and a skin material made of soft vinyl chloride resin is placed on the lower mold surface of the mold, and then polyether polyol and diisocyanate are placed. It is manufactured by a method in which a foam stock solution containing a mixture of the above is injected between a core material and a skin material, and then foamed to form a polyurethane foam and cured. The above foam stock solution can be injected by keeping the mold open and using a liquid injection machine to pour the polyurethane foam stock solution onto the skin material placed on the lower mold surface, or by pouring the polyurethane foam stock solution onto the skin material placed on the lower mold surface. A method is used in which, after a core material is placed in a mold, a polyurethane foam stock solution is press-fitted and filled between the skin material and the core material through an injection port provided in the mold. In the former method, a mechanism has already been developed for moving the nozzle of the liquid injector to correspond to the shape of the desired pad product.

(Problems to be Solved by the Invention) However, in all of the above conventional methods, it is difficult to evenly coat the surface of the skin material and core material with the polyurethane foam stock solution. Tilt the mold to allow the foam solution to flow within the mold and spread the foam solution over the entire surface of the skin and core materials. Depending on the shape of the mold surface, that is, the shape of the pad product, the foam stock solution tends to be unevenly distributed, and as a result, in the past, phenomena such as molding defects, air entrainment, and bubble structure dispersion occur, resulting in large cavities inside. In some cases, defective molded products were obtained. Such cavities can generally be easily confirmed by applying light finger pressure to the surface of the molded product, and therefore, a bad or the like with a defective cavity has no or almost no commercial value.

An object of the present invention is to provide an integral foam molding method that eliminates the above-mentioned problems and can reliably produce the above-mentioned polyurethane foam molded product free of cavity defects.

(Means for Solving the Problems) In the integral foam molding method of the present invention, a core material and a skin material are respectively arranged on the upper mold and lower mold surfaces of a foam mold, and then a polyurethane foam stock solution is applied to the core. The present invention is characterized in that an integral product consisting of a skin material, a polyurethane foam, and a core material is formed by spraying the material and/or the surface of a required part of the skin material, then closing both the upper and lower molds, and foaming the undiluted solution. It is. In the present invention, the polyurethane foam stock solution refers to a foam raw material solution before foaming that contains an isocyanate, a polyhydroxy compound, a blowing agent, and, if necessary, a catalyst, a crosslinking agent, etc., such as an incyanate-containing solution, a polyhydroxy compound, etc. This refers to a liquid that is obtained by mixing the two liquids contained in the liquid immediately before molding. As incyanate, for example, T
DI (lylene diisocyanate) and MDI (methylene diisocyanate) are used, and as the polyhydroxy compound, for example, polyether polyol can be used. All conventionally used drugs can be used as the drugs in the foam stock solution. Further, in the present invention, for example, an ASG board or the like may be used as the core material, and a soft vinyl chloride resin sheet or the like may be used as the skin material.

(Function) The method of the present invention uses a sprayer or the like to spray the polyurethane foam stock solution onto the required surface. Depending on the performance of the spray machine, it is possible to uniformly coat the entire surface of the skin material etc. with the foam stock solution. Therefore, subsequent foaming,
In the curing process, problems such as air entrainment and bubble collapse do not occur, and a polyurethane foam molded product without voids is finally obtained.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

This example is applied to the molding of an automobile instrument panel pad. First, as shown in FIG. 1, the soft vinyl chloride resin skin material 7 and the ASG core material 5, which have been molded into product shapes in separate processes, are placed in the cavity 4 of the open foam mold 1, and the skin material 7 are placed on the mold surface 3a of the lower mold 3, and the core material 5 is placed on the mold surface 2a of the upper mold 2 which can be raised and lowered. Next, a mixture of polyether polyol, crosslinking agent, blowing agent, catalyst, etc. is prepared as liquid A, and MDI is prepared as liquid B, and the mixed liquid 9 of liquids A and B is applied to a two-component spray machine 8 (model: : H2-5SR, N German HE
Spray onto the entire required surface of the skin material 7 without leaving any spots where the coating is leaked (it may also be sprayed onto the surface of the core material 5) using a 300% water-based coating material (manufactured by NNECKE@). The spray amount was 100 cd/υ18y.

Next, both the upper and lower molds are closed, heat is applied if necessary to cause foaming, and the mold is cured for 5 minutes, after which mold 1 is opened.
As shown in FIG. 2, an integrally molded product 10 consisting of a skin material 7, a polyurethane foam 6, and a core material 5 is obtained. This integrally molded product 10 has an average layer thickness of 10 layers of polyurethane foam 6, and no cavities were found when applying finger pressure on the skin material 7, and has sufficient commercial value as an instrument panel pad. Met.

(Comparison example) For comparison, the skin material 7 and the core material 5 were placed in the mold 1 in the same manner as in the example, and then a polyurethane injection machine (model: PU-15, manufactured by Polyurethane Engineer ■) was used. Then, the polyurethane foam stock solution 9 is injected between the skin material 7 and the core material 5 while moving the nozzle of the injector, and then foamed and cured in the same manner as in the example to produce an instrument panel pad as an integrally molded product. When this molded product was pressed with a finger over the skin material, five cavity defects were confirmed per molded product. This defect impairs the commercial value of the pad.

(Effects of the Invention) As explained above, the integral foam molding method of the present invention employs a spraying method that allows the polyurethane foam stock solution to be coated on the required surface without leaking, so that the skin material and core material can be completely free from cavity defects. It is possible to reliably produce an integrally molded product of polyurethane foam and polyurethane foam, and the commercial value of the molded product can be further increased.

[Brief explanation of the drawing]

FIGS. 1 and 2 are views showing the process of molding an instrument panel pad according to the method of the embodiment of the present invention. In the diagram, 1... Foaming mold 2... Upper mold 3... Lower mold 5... Core material 6... Polyurethane foam 7°°°Skin material? ...Polyurethane foam stock solution 10...Integrated molded product□□2]■ Dimensions

Claims (1)

[Claims] The core material and skin material are placed on the mold surfaces of the upper and lower molds of a foam molding mold, and then the polyurethane foam stock solution is sprayed onto the surface of the required areas of the core material and/or skin material, and then both the upper and lower molds are placed. A method for integral foam molding, characterized in that an integral product comprising a skin material, a polyurethane foam, and a core material is formed by closing the base material and foaming the stock solution.