JPS58116140A - Manufacture of extruded synthetic resin molding having surface smoothness - Google Patents

Abstract

PURPOSE:To obtain the captioned extruded synthetic resin molding by a method wherein a molding material for the synthetic resin extruded molding is molded so as to produce an inner layer and a specified molding material for covering protection is molded by extrusion so as to produce an outermost layer, sequentially, the outermost layer of this molding is removed from the inner layer. CONSTITUTION:In case this method is applied to the manufacture of lustrous mold for motor car or the like, for example, at first, polyvinyl chloride or the like having no compatibility with the inner side layer is loaded into an extruder 1 as the molding material which forms the outermost layer for covering protection while ionomer and polyethylene or the like forming the inner side layer, which is the mold, are loaded into the extruders 2, 3 respectively. Subsequently, respective materials are extruded through a mold 5 from adapters 4 of three sets of the extruders 1, 2, 3 to form the molding 10 of three layers construction. Further, the molding 10 is cooled and solidified by a sizing section 6, thereafter, notches are made into the outermost layer 10 by cutters 7, the outermost layer 10a is removed from the inner side layer 10b, and the lustrous mold 10b at the inner side layer is taken up by a take-up machine 11 to obtain the objective extruded molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin extrusion molded product having a smooth surface.

Usually, extrusion molded products have many flow marks in the longitudinal direction, and furthermore, the surface becomes rough after going through the sizing process, making it impossible to obtain a smooth surface and not having very good gloss. . Therefore, when manufacturing an extrusion molded product with a smooth surface, coating the molded product is recommended. After molding, the surface is heated in a heating bath.
It is necessary to smooth the surface by mourning.

This invention focuses on the above points, and aims to provide a method for manufacturing synthetic resin extrusion molded products having good surface smoothness by a simple method without applying surface treatments such as painting. In order to achieve this, a molded product is co-extruded, with the inner layer being the molding material of the original synthetic resin extrusion molded product, and the outermost layer being a protective molding material that is incompatible with the inner layer. The outermost layer of the synthetic resin extrusion molded product is removed from the inner layer of the extrusion molded product.

Hereinafter, this invention will be applied to the production of a glossy mod μ used in automobiles, and nine examples will be described based on aimK.

FIG. 1 shows a schematic diagram of the structure after extrusion and molding to produce a glossy sail, in which 1, 3 and 3 are extruders that extrude different molding materials, and these discharge ports are connected to the adapter section 4! are integrated into one and connected to the mold 311C. A sizing section 6 is disposed behind the mold S for cooling, and cutters 7 are disposed behind the sizing section 6 for making incisions on both sides of the outermost layer of the molded product 10. A pick-up machine is disposed behind the cutter 7 and takes off the outermost layer 10eL of the molded product 10, and // is a take-off machine that takes off the glossy mo/L/10b of the molded product.

Next, a method for manufacturing a glossy molding using the extrusion molding machine having the above configuration will be explained.

First, polyvinyl chloride (PVC) is put into the extrusion @/ as a molding material to serve as the outermost layer for protection.
Extruders 2 and 3 are filled with an ionomer and polyethylene (PE) forming the inner layer of the molded product, respectively. Note that aluminum powder is mixed into the ionomer forming the surface of the molding in order to increase decorative properties.

When each material is extruded from the three extruders 7.2.3 and also extruded from the adapter part DA through the mold S,
A molded article 10 having a three-layer structure as shown in the cross-sectional view of FIG. 2 is extruded. After this molded product 10 is cooled and solidified in the sizing section B, it is sent to a cutter and longitudinal cuts are made at the outermost ends of both sides thereof. The outermost layer 10a, which is divided into an upper part and a lower part by this notch, is taken upward and downward by a taking machine.
The molded product 10 is then peeled off. On the other hand, the inner layer glossy molding/L/10b is taken off by a pulling machine//, and the glossy molding 10b is continuously manufactured. In addition,
The removed outermost layer 10eL can be melted again and reused. Further, the cuts made in both 111 can also be made on the back side of the molded product. Furthermore, in the above example, the inner layer of the molded product is made of ionomer and PE, and the outermost layer is made of PvC. However, if the inner layer and the outermost layer are a combination of incompatible resins, the materials can be selected appropriately. , the inner layer may be made of a single material.In addition, in the above embodiment, after extrusion molding, a notch is made in the outermost layer and the outermost layer is removed from the mold. , and make a notch in the outermost layer during molding.
A cutter is no longer required.

The table below shows the results of an experiment comparing the glossiness of the glossy moldings manufactured by the conventional method and the glossy moldings manufactured by the method of the present invention. It can be seen that better gloss is obtained compared to molding.

As described above, according to the method for producing a synthetic resin extrusion molded product having surface smoothness according to the present invention, the molding material of the original synthetic resin extrusion molded product is used as the inner layer, and a target material that is incompatible with the inner layer is protected. The extrusion molded product is manufactured by coextrusion molding a molded product having the outermost layer of the molding material used for the molding, and then removing the outer ring of this molded product from the inner layer of the synthetic resin extrusion molded product. By extrusion molding, a synthetic resin extrusion molded product having good surface smoothness can be easily produced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic configuration diagram of a forming head of an extrusion molding machine, Fig. 2 is a sectional view taken along line A-A in Fig. 1,
Figure 3 is a sectional view taken along line B-B in Figure 1, and Figure μ is a cross-sectional view taken along line C-- in Figure 1.
It is a sectional view of C. /, 2,3°...extruder, 10...molded product, /Oa
-... Outermost layer, 10b... Glossy mode. Patent application Toyoda Gosei Co., Ltd.

Claims (1)

[Claims] A molded product is co-extruded, the inner layer is the molding material of the original synthetic resin extrusion molded product, and the outermost layer is a molding material for a covering/sac that is incompatible with the inner layer. A method for producing a synthetic resin extrusion molded article having surface smoothness, characterized in that the outermost layer is removed from the inner layer Synthesis 111 resin extrusion molded article.