JPS60260311A - Manufacture of composite molded item with steel - Google Patents

Abstract

PURPOSE:To produce a molded item excellent in strength and good in electromagnetic sheilding, by putting an expanded metal of a thin steel plate and a thermosetting resin together and molding them together. CONSTITUTION:A lath (expanded metal of a thin steel plate) 1 is worked into a shape in conformity with the shape of a bottom force 4. Then the lath and a molding material 2 of a thermosetting synthetic resin are put together and are inserted into the cavity defined by the bottom force 4 and a top force 3 that have been previously heated. Successively, the top force 3 is pressed, and the top force 3 and the bottom force 4 are heated to mold the lath 1 and the molding material 2 integrally. Thus a composite molded item 5 can be produced in the same conventional manner as for the molding of the thermosetting resins, and further the lath 1 can be prevented from breaking due to the molding material 2 that is filled in the cavity and is fluid when the molding is performed. The composite molded item 5 can be mass-produced and used as housing material for computers, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a steel-filled laminated composite molded product in which an expanded metal made of a thin steel plate and a thermosetting resin are integrally molded.

[Prior art]

BACKGROUND ART The development of electronic devices in recent years has been remarkable, especially with the improvement of peripheral technologies such as various printed wiring boards and integrated circuits that form the basis of electronic devices. It is naturally expected that as the amount of these electronic devices increases significantly, the number of various troubles that occur will increase.

The biggest cause of this is the influence of electromagnetic waves on these electronic devices.For example, in computers, it can lead to misleading information and errors in calculations, and in display devices such as VTRs, it can cause problems in terms of images such as colors. As a very familiar example, electronic equipment installed in a car continues to receive electromagnetic waves from a spark plug ever since the starter is turned on to put the car into operation, causing noise. It is known that there are.

As described above, there are countless sources of electromagnetic waves in the surrounding area, and therefore, measures are taken to prevent these electronic devices from being affected as much as possible.

Specifically, for example, the shielding of a specific part within a normal TV receiver or the shielding of the entire housing of a computer is possible.

In general, with the mass production of electronic devices, housings etc.
Although they are made of synthetic resin molded products, it is conceivable to insert a wire mesh into these molded products in order to shield them from electromagnetic waves. However, the contact conditions at the contact points of the wires that form the wire mesh are uneven and unstable, which may cause fluctuations in the electromagnetic wave shielding performance. It is difficult to form a smooth surface unless the resin layer has a certain thickness or more.

It is also conceivable to knead a conductive filler separately from the wire mesh. In this case, if the crosstalk conditions are carefully considered, the filler will be dispersed uniformly in the resin and non-uniformity will disappear, but if fibrous filler is mixed in the resin, there will naturally be a limit to the amount of filler added. Therefore, it is difficult to obtain a sufficiently satisfactory electromagnetic shielding effect.

Furthermore, methods such as applying conductive paint or metal spraying may be considered, but in these cases, they would be too complicated unless a separate process for treatment (and of course a preparation process is also added). Not only is it unsuitable for mass production, but it is also undesirable because it is simply painted or thermally sprayed, so there is a good chance that it will peel off.

[Purpose of the invention]

This invention proposes a method for manufacturing a laminated composite molded product containing steel, which improves the above-mentioned drawbacks and can easily produce a molded product with excellent electromagnetic shielding performance.

[Summary of the invention]

The method for producing a steel-filled composite molded product of the present invention is to stack expanded metal made of thin steel plate and thermosetting synthetic resin molding material in a mold cavity between an upper mold and a lower mold of preheated compression molding metal. This is a method in which the expanded metal made of thin steel plate and the thermosetting synthetic resin are integrated into a predetermined shape by pressurizing and heating after inserting them together.

Thin steel sheets with a thickness of 100 μm or less are currently manufactured using the cold rolling method. z-pi+
, ゛ ,,.

Ru. In this type of cold rolling method, a cold rolled steel sheet is either left untreated or subjected to surface treatments such as galvanizing or tin plating and then further rolled to produce a thin steel sheet. Expanded metal C made from a thin steel sheet produced by processing the thin steel sheet manufactured in this manner is hereinafter referred to as lath. ) has various features such as being flat and having excellent electromagnetic shielding performance.

By overlapping this lath and thermosetting synthetic resin molding material and integrally molding it, the thermosetting synthetic resin is heated and pressurized in the mold cavity, softens and becomes fluid, and fills the entire cavity. The molding material can reduce the stress on the fracture-prone cross section of the lath, and it is possible to obtain a steel-filled composite molded product with excellent electromagnetic shielding performance and a smooth surface without the lath breaking.

〔Example〕

FIG. 1 (aXbXc) is a diagram showing the steps of an embodiment of the present invention. In the figure, 1 is a lath, 2 is a thermosetting synthetic resin to be molded by overlaying it with the Fi lath 1, for example, a molding material such as SMC, 6 is an upper mold of a compression molding mold, 4 is a lower mold, and 5 is a thermosetting material with the lath 1. It is a steel-filled composite molded product that is integrally molded with 2' feet of synthetic resin molding material.

The process of this embodiment will be explained according to the drawings. First, as shown in FIG. Next, as shown in FIG. 1(b), the lath 1 and the thermosetting synthetic resin molding material 2 are superimposed and inserted into the mold cavity between the upper mold 3 and the knife mold 4 which have been preheated. Thereafter, as shown in FIG. 1(a), the upper mold 6. Heat the lower mold 4 and add lath 1 and molding material 2? ! -Molded in one piece. When used as a thermosetting synthetic resin in SMC', the pressure is approximately 50 kg/cr&, and the heating temperature is approximately 150 kg/cr&.
Pressure and heat at ℃ for 3 to 6 minutes. Next, if necessary, use the upper mold 6. Lower mold 4t - cooled punching upper mold 3. The lower mold 4 is opened and the steel-filled composite molded product 5 is taken out.

According to the method for manufacturing the steel-filled composite molded product 5 described above, the steel-filled composite molded product 5' can be molded in the same manner as the molding of ordinary thermosetting synthetic resin, and furthermore, the fluidity that fills the cavity during molding is W class 1 fracture can be prevented in the molding material 2 having the following properties.

Although the above embodiment shows the case where the lath 1 is pre-processed before being inserted into the cavity between the upper mold 3 and the lower mold 4, it is also possible to integrally mold the lath 1 with the molding material without pre-processing.

FIGS. 2(a) and 2(b) show the steps of an embodiment in which the lath 1 is not pre-processed. As shown in Fig. 2 (4), the lath 1 without pre-processing and the thermosetting synthetic resin molding material 2 are placed in the upper mold 3.
and the lower mold 4, and then as shown in FIG. 2(b), the steel-filled composite molded product 5 is molded by applying pressure and heating as in the case of the first embodiment. can do. In this embodiment, the excess portion 6 of the lath 1 can be cut off by the shear edge of the upper die 6 and the lower die 4.Next, SMCt- is used as the thermosetting synthetic resin, and by the manufacturing method of the present invention. Manufactured steel-filled composite molded plate and S
Table 1 shows the mechanical properties of MC.

Table 1 Nest position kg/- The lath is 100μ thick, mesh 2IlllIX3
These are the measurement results when molding was performed using No. 11111.

As shown in Table 1, the steel-filled composite molded plate has tensile strength and bending strength similar to those of SMC alone, and the bending modulus is improved.

In addition, the mesh size is 2 x 3, and the thickness is 70 μm and 100 μm.
Figure 3 shows the results of an investigation of the electromagnetic shielding performance ft of a steel-containing composite molded product formed using laths of m and SMC'. In the figure, f is the frequency of electromagnetic waves, A shows the case where the thickness is 70 μm, and B shows the case where the thickness is 100 μm. As is clear from the figure, according to the manufacturing method of the present invention, the laths do not break, so that electromagnetic shielding performance of about AD dB can be satisfied over a wide range of frequency bands.

〔Effect of the invention〕

According to the method of manufacturing a steel-filled composite molded product of the present invention, it is possible to easily produce a molded product with excellent electromagnetic shielding performance and strength because it can be integrally molded with a thermosetting synthetic resin without breaking the lath.
Can be used for IA construction, computers, electronic equipment)
It can be used for mass production of clean room wall materials at the Uzing and IC9 manufacturing plants.

[Brief explanation of drawings]

Fig. 1 (-), (b),
FIG. 6, which is a diagram showing the steps of another embodiment of the present invention, is an electromagnetic shielding performance diagram of a steel-containing composite molded product manufactured according to the present invention. DESCRIPTION OF SYMBOLS 1... Expanded metal made of thin steel plate, 2... Molding material of thermosetting synthetic resin, 6... Upper mold, 4... Lower mold, 5... Steel-containing composite molded product. Agent Patent Attorney Sanro Kimura Figure 1 (0) ↓ (C) 3

Claims (1)

[Claims] After inserting the thin steel sheet expanded metal and the thermosetting synthetic resin molding material into the mold cavity between the upper and lower molds of a preheated compression molding mold, they are heated under pressure and then thinned. A method for manufacturing a steel-filled composite molded product, which is characterized by integrally molding expanded steel plate metal and thermosetting synthetic resin.