JPH0663975A - Production of resin molding - Google Patents

Abstract

PURPOSE:To prevent the generation of a crack and to improve the surface quality of a resin molding when a resin molding has a box shape or unevenness such as a rib. CONSTITUTION:A space 3 is provided by a first mold 1 and the second mold 2 made movable with respect to the first mold 1 and a molding material 4a is subjected to compression molding in the space 3 to form a resin molded object 4 and a coating layer is subsequently formed on the surface of the resin molded object 4. In this molding method, two or more kinds of molding materials 4a', 4a'' containing reinforcing fibers different in length are used and the molding material 4a' containing long fibers is arranged to the part corresponding to the coating material injection port 8 of the mold to perform molding. By this constitution, even when the injection pressure from the coating material injection port 8 is concentrated to one place, no crack is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin molded article, and more particularly to a method for producing a resin molded article having a coating layer for improving the surface quality of the resin molded article.

[0002]

2. Description of the Related Art Conventionally, the in-mold coating method is a method for producing a resin molded product by coating the surface of the resin molded product in the same step as molding of the resin molded product.
As disclosed in Japanese Patent No. 9291, there is a method of completely opening the molding die and pouring the coating material into the molding die, or a method of pouring the molding material with the molding die closed. In addition, JP-A-61-2
As disclosed in Japanese Patent No. 73921, there is a method of injecting a coating material into a molding die under high pressure while pressing the molding die.

[0003]

However, when the shape of the resin molded product is a box shape instead of a flat plate shape, or even if it is a flat plate shape and has irregularities such as ribs, the coating material is used as a molding die. There is a problem that the injection pressure at the time of injection is concentrated on a part of the resin molded body and cracks occur in the resin molded body.

The present invention has been made in view of the above problems of the prior art, and its object is to provide a resin molded product having a box-like shape or an unevenness such as ribs. Another object of the present invention is to provide a method for producing a resin molded product, which can eliminate defects such as cracks and improve the surface quality of the resin molded product.

[0005]

In order to solve the problems of the above-mentioned conventional examples and to achieve the object of the present invention, a method for producing a resin molded article of the present invention is provided with a first molding die 1 and a first molding die 1. A space 3 is provided by a second molding die 2 which is movable with respect to the molding die 1, and a molding material 4a is compression-molded in the space 3 to form a resin molding 4, and then the resin molding 4 is formed. Four
In the molding method for forming the coating layer 5 on the surface, two or more molding materials 4a ′, 4 having different fiber lengths of reinforcing fibers are used.
a "is used to form a molding material 4a 'having a long fiber length in a portion corresponding to the coating material injection port 8 of the molding die, and molding is performed by using such a method. Thus, the problems of the conventional example described above are solved and the object of the present invention is achieved.

[0006]

According to the present invention having the above-described method, two or more molding materials having different fiber lengths of reinforcing fibers are used, and a molding fiber having a long fiber length is formed at a portion corresponding to the coating material injection port 8. By arranging and molding the material 4a ', when the coating material 5a is injected from the coating material injection port 8, the portion to which the injection pressure is applied has a long fiber length.
Since a'is molded, the resin molded body 4 can be prevented from cracking.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 shows an explanatory view of a molding die used in the present invention, and FIGS. 2 to 7 show the manufacturing order.
In the embodiment shown in the accompanying drawings, a bathtub will be taken up as an example of a resin molded product for description.

The mold device comprises a first mold 1 as a lower mold.
And a second molding die 2 serving as an upper die, and in the embodiment shown in the accompanying drawings, the first molding die 1 is a fixed die,
The second mold 2 is a movable mold, and the second mold 2 is moved in the vertical direction by a cylinder device 7 such as a hydraulic cylinder. In the figure, 20 is a press ram,
21 is a pressure control valve, 22 is a pump, 23 is a press pressure controller, and 24 is a mold displacement meter. A coating material injection port 8 is provided in the first mold 1, and the coating material 5a can be injected from the coating material injection port 8 by a coating material supply device 9 such as an injection cylinder. In the figure, 25 is a tank, 26 is a stroke detection device for the injection cylinder, 27 is a flow control valve, 2
Reference numeral 8 is a pressure control valve, and 29 is a pump. An opening / closing valve 10 is provided at the coating material inlet 8.

[0009] Therefore, the bath A having the coating layer 5 on the surface of the resin molded body 4 is manufactured by using the above-mentioned mold apparatus.
The manufacturing process is as follows.
That is, first, as shown in FIG. 2A, the second molding die 2 is raised to form the space 3, and in this state, the resin molding 4 is formed.
The molding material 4a, which is the material of (1), is placed on the first molding die 1. Here, as the molding material 4a, the reinforcing fiber is 3 to 25 m.
Fiber-reinforced thermosetting resin using fibrous reinforcing material such as glass fiber or carbon fiber of m is used. BMC with a mixture of fibrous reinforcing material, thickener, colorant, etc. if necessary
(Bulk molding compound) and SMC
(Sheet molding compound) or the like is placed on the first mold 1 and supplied. BMC here
When a molded product such as the bath A is manufactured by using, the sheet-shaped BMC material is appropriately cut according to the shape of the molded product and placed on the first molding die 1 kept at the molding temperature. Next, FIG.
As described above, the second molding die 2 is lowered and clamped to compress the molding material 4a under pressure to mold the resin molding 4. next,
As shown in FIG. 4, the second molding die 2 is slightly lifted to form a slight gap between the back surface of the resin molding 4 and the second molding die 2, and then opened and closed as shown in FIG. The valve 10 is opened, and the coating material 5a, which is a molding material made of a resin such as an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, an acrylic resin, or a mixture of these resins, is coated by the coating material supply device 9. It is injected from the inlet 8 into a slight gap between the surface side of the resin molding 4 and the first molding die 1. When the injection of the coating material 5a is completed in this way, the on-off valve 10 is closed as shown in FIG. 6 and recompression molding is performed. After this recompression molding, the second molding die 2 is raised to open the die as shown in FIG. 7, and the bath A is taken out in this state.

By the way, when the box-shaped resin molded product such as the bath A is manufactured as described above, the resin molded body 4 is compression molded and then contracted to form a convex first resin mold 1. Since the body 4 bites, when pouring the coating material 5a between the convex first molding die 1 and the resin molding 4,
It is difficult to secure a gap filled with the coating material 5a, and when the coating material 5a is injected with the gap being small, the injection pressure is concentrated on the resin molding 4 near the coating material injection port 8. Therefore, in the present invention,
It is characterized in that the portion corresponding to the coating material injection port 8 of the resin molded body 4 is configured to have higher strength than other portions so as to withstand this injection pressure. Therefore, the coating material of the resin molded body 4 is Coating is performed by setting the fiber length (for example, glass fiber length) of the portion corresponding to the injection port 8 portion to about 12 to 25 mm and setting the fiber length (for example, glass fiber length) of the other portion to about 3 to 5 mm. The strength of the resin molded body 4 in the portion corresponding to the material injection port 8 is increased.
In the figure, 4a 'is a molding material having a long fiber length (BM
C) and 4a ″ is a molding material (BM) having a short fiber length.
C) is shown.

FIG. 8 shows another example in which the molding material 4a, which is the material of the resin molding 4, is placed on the first molding die 1. That is, in this embodiment, the molding die 1
A molding material 4a 'having a long fiber length is placed directly above the upper coating material injection port 8 and a molding material 4a "having a short fiber length is laminated on the molding material 4a' having a long fiber length.

The glass fiber in the portion corresponding to the coating material injection port 8 may be a continuous continuous mat. By forming as described above, even if the injection pressure is concentrated on the resin molding 4 near the coating material injection port 8, cracks do not form from the vicinity of the coating material injection port 8 of the resin molding 4 and the surface quality is improved. The excellent bathtub A can be manufactured.

The coating material 5 used in the present invention
In addition, a may be added with an inorganic substance such as mica powder or glass powder or a metal powder such as copper, nickel or aluminum in order to form a color or a pattern.

[0014]

As described above, according to the present invention, two or more kinds of molding materials having different fiber lengths of reinforcing fibers are used, and a fiber having a long fiber length is provided at a portion corresponding to a coating material injection port of a molding die. Since the molding material is placed and molded, even though the injection pressure of the coating material concentrates on the part corresponding to the coating material injection port of the resin molded body, it is possible to prevent cracks from entering this part and improve the surface quality. An excellent resin molded product can be manufactured.

[Brief description of drawings]

FIG. 1 is an explanatory view of a molding die for manufacturing the present invention.

FIG. 2 is an explanatory view showing the manufacturing sequence of the same, FIG. 2 (a) is a schematic front view of a state where molding materials having different fiber lengths are placed on the first mold, and FIG. 2 (b) is a fiber length. It is a schematic plan view of a state where molding materials having different thicknesses are placed on the first mold.

FIG. 3 is an explanatory view showing the manufacturing sequence of the above.

FIG. 4 is an explanatory view showing the manufacturing sequence of the above.

FIG. 5 is an explanatory view showing the manufacturing sequence of the above.

FIG. 6 is an explanatory view showing the manufacturing sequence of the above.

FIG. 7 is an explanatory view showing the manufacturing sequence of the above.

FIG. 8 is an explanatory view showing another example in which a molding material having a long fiber length and a molding material having a short fiber length are placed on the molding die of the same.

[Explanation of symbols]

 1 1st shaping | molding die 2 2nd shaping | molding die 3 Space 4 Resin molding 4a Molding material 4a 'Molding material with long fiber length 4a "Molding material with short fiber length 5 Coating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshikazu Maki 5-8 Nishimitabicho Suita City, Osaka Prefecture Japan Catalysis Resin Research Laboratory Co., Ltd. (72) Inventor Shigeru Oka 5-8 Nishimitabicho Suita City, Osaka Prefecture No. Japan Catalyst Resin Research Institute

Claims (1)

[Claims] 1. A resin molding is formed by forming a space by a first molding die and a second molding die movable with respect to the first molding die, and compressing and molding a molding material in the space. Then, in a molding method for forming a coating layer on the surface of the resin molded body, two or more kinds of molding materials having different fiber lengths of reinforcing fibers are used, and the fiber length is applied to the portion corresponding to the coating material injection port of the molding die. A method for producing a resin molded product, which comprises arranging and molding a molding material having a long length.