JPS62121027A - Composite parts - Google Patents

Abstract

PURPOSE:To prevent generation of a warp of a thin metallic base plate, by joining a synthetic resin material composed of polyamide resin, which contains mica and is in specific properties, to a hard base plate unitarily at the time of molding. CONSTITUTION:As a metallic base plate to be used for composite parts, metallic parts being used for various electric products such as VTRs are mentioned, which is either a plate whose thickness is thin (less than 1mm) or a slender and thin metallic plate. Then as polyamide resin, a substance whose underwater saturation water absorption rate at 20 deg.C is less than 5% is used, as mica which is made to contain into the polyamide resin, for example, loading of the same is decided to be the 10-50wt% mica to 90-50wt% polyamide resin. Both are made into pellets by performing kneading and extruding once by an extruding machine after those have been blended. A molded material is obtained by performing outsert molding on the surface of the metallic base plate whereon various form holes are bored by an injection forming method by making use of the pellets.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite component formed by composite of one or more synthetic resin bodies on a hard substrate such as metal. In particular, the present invention relates to composite parts in which a synthetic resin body is composited onto a metal substrate by an outside molding method.

[Conventional technology and problems]

2. Description of the Related Art Conventionally, composite parts made by integrally bonding a synthetic resin body to a metal substrate by outside molding during molding have been used as parts for electrical products such as VTRs.

The outside molding method is a method that allows parts in which multiple synthetic resin bodies are bonded onto a single rigid substrate to be manufactured in a single molding operation. This is a method to obtain an integrated composite part by mounting the created hard substrate in a mold and injecting synthetic resin into it by injection molding and solidifying it.The synthetic resin is inserted into the notch hole provided in the substrate. It is bonded to the substrate by filling. Because the relationship between the resin and the substrate is the opposite of the relationship between the metal and resin in conventional metal inserts, it is called "outsider" and is being widely adopted in tape recorders, watches, etc. 6 Conventional outsidesard molding involves: Polyacetal resin is often used as a synthetic resin.

However, as electronic products have recently become smaller and more sophisticated, conventional outside molded products using polyacetal resin have been difficult to manufacture, especially for thin-walled metal parts, due to shrinkage of the synthetic resin body integrally bonded to the metal substrate. Problems such as warping of the board have occurred.

[Means for solving problems]

The present inventors have made earnest efforts to solve these problems, and as a result, have arrived at the present invention.

That is, the present invention relates to a composite component in which a synthetic resin body made of a polyamide resin containing mica and having a saturated water absorption rate of 5% or less in 20° C. water is integrally bonded to a hard substrate during molding.

Examples of the metal substrate used in the composite part of the present invention include metal parts used in various electrical products such as VTRs, and are particularly easy to warp and have a thin plate thickness (less than 1 dragon). Or it is an elongated thin metal plate. Examples of metal plates used include cold rolled steel plates and aluminum plates.

Next, the synthetic resin used in the present invention has a saturated water absorption rate of 5% or less in water at 20°C, preferably 3% or less, and specifically, nylon-11 (saturated water absorption rate of 1.85 in water at 20°C).
%), nylon-12 (saturated water absorption rate 1.5%), and nylon-612 (saturated water absorption rate 3.0%). The melt index (Ml) values of these polyamide resins are between 5 and 90 g/10 minutes. The method for measuring Ml value is AS.
TM D-1238 (Temperature 230℃ 1 load 2160g)
This is due to If the old value is outside the above range, only a molded product will be obtained that is unsuitable as a functional part of a composite part.

The mica to be contained in this polyamide resin may be of any chemical composition, for example, what is commonly called mica, such as muscovite, soda mica, rhodotite, biotite,
It contains various types of phlogopite and iron mica, and is preferably what is usually called gold mica or phlogopite mica, and has an aspect ratio of 15 or more, preferably 30 to 70. Generally, if the aspect ratio is less than 15, a sufficient reinforcing effect cannot be obtained. On the other hand, the particle size is preferably 60 or less, preferably 50 or less. If it exceeds In, the surface condition of the molded product will deteriorate and there is a risk of damaging the mating member.

The blending amount is 90 to 50% by weight of polyamide resin and 10 to 50% by weight of mica, preferably 80% by weight of polyamide resin.
-60% by weight and mica 20-40% by weight.

In the present invention, it is preferable to add a silane coupling agent to improve the compatibility between the polyamide resin and mica.

The amount of silane coupling agent to mica is 0.
It is 1 to 10% by weight, preferably 0.5 to 5% by weight.

Silane cuffing agents are broadly classified into epoxy-based and amine-based, but epoxy-based cuffing agents may be crosslinked in some cases, and it is preferable to use amine-based silane coupling agents. More preferred is N-β (aminoethyl)T-aminopropyltrimethoxysilane. It is preferable to surface-treat the mica with a silane coupling agent before blending it with the resin, but blending the mica and the resin with a silane coupling agent at the same time will not significantly impair the properties, and from an economic point of view, Are better.

Conventionally known plasticizers and stabilizers can be added to these polyamide resins used in the present invention.

Although the composite parts of the present invention include those manufactured by conventional insert molding methods, those manufactured by outside molding methods are preferred. As the outside molding method, a conventionally known injection molding method is used.

〔Example〕

Next, examples of the present invention will be shown, but the present invention is not limited thereto.

Example-1 12.70 parts by weight of nylon with an old value of 12, 30 parts by weight of mica (Sujirite Mica 325S: manufactured by Kuraray) with an average weight aspect ratio of 30 or more and a particle size of 50 or less and 0.3
After blending part by weight of N-β (aminoethyl)γ-aminopropyltrimethoxysilane, kneading and extrusion were performed once in an extruder to obtain pellets with a good appearance.

Using these pellets, a part of the surface of a metal part consisting of an elongated metal plate with a thickness of 18 mm, a width of 18 mm, and a length of 235 mm, in which holes of various shapes are made, was formed using a well-known injection molding method. A composite part in which a functional part made of a nylon-12 molded body was integrally bonded to a metal plate was obtained by outside molding using a method. This product is used as a part of electrical products.

Comparative Example-1 Using the same metal parts as in Example-1, outside molding was performed using polyacetal resin in the same manner as in Example-1 to obtain composite parts of the same shape.

When the outside molded products obtained in Example-1 and Comparative Example-1 were left for a long period of time and their changes over time were investigated, the molding shrinkage rate of the products obtained in Example-1 was 0.6%. Although the warpage was small and hardly occurred, the product obtained in Comparative Example 1 had a molding shrinkage rate of 2.5%, which caused a large warpage, which caused problems in use as parts of electrical products.

Claims (1)

[Scope of Claims] 1. A composite part formed by integrally bonding a synthetic resin body made of a polyamide resin containing mica and having a saturated water absorption rate of 5% or less in 20°C water to a hard substrate during molding. 2. The composite part according to claim 1, wherein the molding is performed by outside molding.