JP2002001789A - Method for extruding synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that a skin layer, which is protruded largely from a main body layer by a conventional means, has to be cooled to mold the skin layer while being cooled, when a pattern is applied, a special molding device is required to need equipment investment, and extrusion speed has to be increased so that severe production conditions are necessary to make it difficult to obtain uniform quality, and the decrease in speed of the main body layer causes the decrease of production speed. SOLUTION: In a method for extruding a synthetic resin for producing an extrusion-molded article having the main body layer and the skin layer of the synthetic resin which is laminated on the main body layer, the ratio of the discharge of the skin layer to that of the main body layer is adjusted at 0.035-0.045 time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin extruding method for producing an extruded article having a synthetic resin skin layer, and more particularly to a method for forming a pattern on the skin layer and molding the same using a commonly used molding machine. The present invention relates to a synthetic resin extrusion method.

[0002]

2. Description of the Related Art Conventionally, as means for laminating a synthetic resin skin layer as a pattern with irregularities, for example, Japanese Unexamined Patent Publication No.
As in the case of No. 1-320645, there is a means for extruding the skin layer at a higher speed than the main body layer and intermittently retaining the skin layer on the main body layer to form a pattern.

[0003]

However, such means has a problem that since the skin layer protrudes significantly from the main body layer, air must be cooled to form the skin layer while cooling it. Therefore, when forming a pattern, a special molding device is required, and there has been a problem that capital investment is required. In addition, since extrusion must be performed at a higher speed than a normal extrusion speed, there is a problem that manufacturing conditions are severe and it is difficult to obtain uniform quality. To solve this problem, the speed of the main body layer may be reduced, but this causes a new problem that the overall manufacturing speed is reduced.

[0004] The object of the present invention is to focus on such a problem, and it is possible to manufacture with a normal manufacturing apparatus without the need for new equipment, to easily obtain uniform quality, and to provide unevenness on the skin layer. Another object of the present invention is to provide a synthetic resin extrusion method which can be manufactured at a high speed.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and have found that an extruded article provided with a main body layer and a synthetic resin skin layer laminated on the main body layer. In a synthetic resin extrusion method manufactured by multilayer extrusion, the present invention was completed by specifying the discharge weight of the skin layer in relation to the main body layer.

That is, the present inventor has found that when the synthetic resin as the skin layer is laminated on the main body layer from the discharge port, the synthetic resin is subjected to a resin pressure of the main body layer which is much higher than the resin pressure of the skin layer. It has been found that the ejection weight is interfered and the ejection weight at the skin layer ejection opening becomes non-uniform.

[0007]

In the present invention, the discharge weight of the skin layer is 0.035 times to 0.045 times the discharge weight of the main body layer.
The reason for this is to form irregularities on the surface of the skin layer. The above range is preferable because the discharge weight of the skin layer becomes non-uniform from a certain value as it is reduced, but if it is too small, the discharge layer is broken and the skin layer itself is torn. In addition, the skin layer may be partially laminated as well as the entire surface of the main body layer.

As the synthetic resin used as the skin layer, any synthetic resin that can be extruded can be appropriately used. For example, hard vinyl chloride resin, ABS (acrylonitrile-butadiene-styrene), AES (acrylonitrile. Diene copolymer) / styrene),
There is a simple substance or a composite such as AAS (acrylonitrile / acrylic rubber / styrene) and polycarbonate.

The main body layer in the present invention may be any material capable of laminating a synthetic resin as the skin layer and stably maintaining it for a long period of time. Specifically, the synthetic resin used as the skin layer can be appropriately selected. It may be of the same type or different type as the skin layer.

[0010] Shapes formed by the present invention include:
The shape conventionally formed as an extruded product can be appropriately selected, and specific examples include a plate shape, a rod shape, a tubular shape, a gutter shape used in eaves gutters, and the like.

According to the present invention, in a synthetic resin extrusion method for producing an extruded product having a main body layer and a synthetic resin skin layer laminated on the main body layer, the discharge weight of the skin layer is controlled by the following method. It is characterized by being 0.035 times to 0.045 times the discharge weight of the main body layer, and forming a concavo-convex pattern with the maximum thickness of the skin layer as an initial set value (thickness at discharge). It can be manufactured with ordinary manufacturing equipment without the need for equipment and can easily obtain uniform quality, and can be manufactured at high speed even if the skin layer has irregularities. The weight of the skin layer can be adjusted by adjusting the screw diameter of the extruder and the number of revolutions thereof.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a synthetic resin extrusion production line embodying a synthetic resin extrusion method according to the present invention will be described in detail below with reference to FIG. FIG. 1 is an explanatory diagram showing a synthetic resin extrusion production line embodying the synthetic resin extrusion method according to the present invention.

In FIG. 1, reference numeral 1 denotes an extruder for a main body layer, 2 denotes an extruder for a skin layer, and 3 denotes a two-layer mold.
Are attached to the extremities of the body layer extruder 1 and the skin layer extruder 2. Reference numeral 4 denotes a manufactured synthetic resin extruded product, and reference numeral 5 denotes a molding device. In addition, in this example and the comparative example described later, a tubular extruded product made of a synthetic resin was employed, and a skin layer covering the entire outer periphery thereof was employed.

The production process in this synthetic resin extrusion production line will be described. While the rigid polyvinyl chloride resin for the main body layer is extruded from the extruder 1 for the main body layer to the two-layer mold 3, AES (acrylonitrile / (ethylene / propylene / diene copolymer) / styrene) for the skin layer is extruded. It is extruded into a two-layer mold 3, and a synthetic resin extruded product 4 in which the skin layer is laminated on the main body layer is manufactured. Next, the synthetic resin extruded product 4
Is transferred to the molding device 5 and molded.

Next, in order to explain the features of the present invention, an embodiment in which the discharge weight of the skin layer is changed in this production line will be described with reference to Table 1 in comparison with a comparative example. Table 1 shows the state of the pattern for each skin layer discharge weight. In Table 1, “the discharge weight of the skin layer / the discharge weight of the main layer” is “the ratio of the discharge weight of the skin layer to the discharge weight of the main layer in volume conversion”. ”,“ X ”in the“ pattern state ”indicates that the pattern was not formed and the surface was smooth, △ indicates that the pattern was partially formed,
○ means that the pattern was uniform.

[0016]

[Table 1]

As shown in Comparative Examples 1 to 3 and the examples, no pattern was formed unless the discharge weight of the skin layer was reduced to a certain extent. Further, as shown in Examples and Comparative Example 4,
If the skin layer ejection weight was too small, the skin layer itself was intermittently ejected and the pattern became non-uniform.

[0018]

According to the present invention, there is provided a synthetic resin extruding method for producing an extruded article having a main body layer and a synthetic resin skin layer laminated on the main body layer by multi-layer extrusion. The discharge weight of the skin layer is 0.035 to 0.045 times the discharge weight of the main body layer,
As a result, it is possible to manufacture with a normal manufacturing apparatus without requiring new equipment, and it is easy to obtain uniform quality, and it is also possible to manufacture at high speed even if unevenness is provided in the skin layer.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a synthetic resin extrusion production line embodying a synthetic resin extrusion method according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 extruder for body layer 2 extruder for skin layer 3 two-layer mold 4 molding machine 5 extruded product

Claims (1)

[Claims] 1. A synthetic resin extrusion method in which an extrusion molded article having a main body layer and a synthetic resin skin layer laminated on the main body layer is manufactured by multi-layer extrusion, the discharge weight of the skin layer is reduced by the body weight. A synthetic resin extrusion method characterized by being 0.035 to 0.045 times the discharge weight of the layer.