Process for producing composite molding

Abstract

A process for producing a liquid-crystalline polymer/metallic part composite molding stably having satisfactory adhesion. A reduction in molding cycle time can be attained in the process. The process is characterized in that (1) a mold is used which is divided into a main mold for controlling linkage with a molding machine and a core which has a circuit for heating and a circuit for cooling and involves inside an area where a liquid-crystalline polymer comes into contact with a metallic part. The process is further characterized in that (2) that part of the mold which comes into contact with the resin flowing in during molding has been surface-treated so as to have a ten-point average roughness (Rz) of 0.5 [mu]m or less, and the core has a capacity of 60 cm3 or less and has been embedded in the main mold, with that peripheral part of the core which is in contact with the main mold having been heat-insulated. The process is furthermore characterized by (3) setting the metallic part in the mold, heating the core to a temperature in a specific range, injecting the liquid-crystalline polymer to fill the cavity therewith while keeping that temperature of the core, and immediately after completion of the filling of the mold cavity with the resin, blocking the heating circuit of the core and rapidly cooling the core with the cooling circuit of the core at a cooling rate of 7 DEG C/sec or higher.

Description

technical field [0001] The present invention relates to a method for producing a composite molded product of a liquid crystal polymer and a metal part. Specifically, it relates to a method for manufacturing a composite molded product that ensures excellent adhesion between a liquid crystal polymer and a metal part and improves the molding cycle. Background technique [0002] Composite molded products composed of resin and metal represented by insert molded products are used in the manufacture of electrical and electronic parts, automobile parts, etc. However, the interface between the metal insert and the resin cannot be sufficiently tightly bonded by the usual molding method, which may cause detachment or leakage of gas or liquid from the interface. In order to improve such disadvantages, there is known a method of surface-treating metal to form irregularities, and injecting molten resin into the irregularities. According to this method, a composite molded product of resin...

AI Technical Summary

Problems solved by technology

According to this method, a composite molded product of resin and metal with excellent interface adhesion can be obtained. However, since chemicals are used for surface treatment, when this method is actually introduced, there are problems in the introduction of equipment, management of chemical solutions, etc. , it is more difficult to consider in terms of cost increase

[0003] In addition, as a method of improving the adhesion by heating the insert, the following molding methods have been proposed. 1) The metal that has been heated in advance is accommodated in the mold, and then the injection molding is performed; 2) The electric heater is used in the mold. Heating means such as electromagnetic induction heats the embedded metal and performs injection molding; 3) Keep the mold temperature at a high temperature and cool it after injection molding, etc. However, since the time from the completion of heating to injection is different in 1) and 2), Therefore, the temperature of the embedded metal tends to decrease, especially when using small, thin inserts, this effect is difficult to obtain

In addition, regarding 3), it is necessary to control the temperature of the entire mold during heating and cooling, a heater and a cooling system with a large heat capacity are required, and there is a problem that molding takes a very long time

[0004] In addition, in Japanese Patent Application Laid-Open No. 2001-1382, there is proposed a method in which molten resin is flowed into a system heated above the melting point by an insert heating method, the pressure is maintained, and the temperature is lowered and the load pressure is increased. This kind of control improves the close bonding between resin and metal, but requires strict control of temperature and pressure, and there is a tendency to increase auxiliary equipment, so it cannot be said to be practical.

In addition, in Japanese Patent Laid-Open No. 2001-1382, resins such as low-density polyethylene resin, polypropylene, and polystyrene are assumed, and in the case of liquid crystal polymers, the method of Patent Document 1 cannot obtain a combination of resin and metal. Composite molded product with good adhesion

[0005] On the other hand, in Japanese Patent Laid-Open No. 2005-342922, it is proposed to use a mold with a surface treatment using a diamond carbon film to improve the tight bonding strength between metal and resin. However, in this solution, there is The problem that molding cannot be performed with a practical molding cycle time

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