JPH0524052A - Casting method for epoxy resin - Google Patents

Abstract

PURPOSE:To remove foams completely by preheating a casing main body up to 60-100 deg.C by a heater coil disposed on the periphery of a supersonic vibration device while being vibrated on a vibration bed vibrated by the supersonic vibration of several MHz. CONSTITUTION:A casing main body 4 is preheating up to 60-100 deg.C by a heater coil 8 disposed on the periphery of a supersonic vibration device 7 while being vibrated on a vibration bed 10 by the supersonic vibration of several MHz. Epoxy resin 2 containing a filler 5 in the molten state is cast from the upper section of the casing in said state. The generation of crack by residual solidification of cells 3 in the casing 4 at the time of casting is prevented by said arrangement, and the lowered quality generated by deterioration of insulating properties and lowered sealing performance is also prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for casting an epoxy resin for insulating an electric wire cable and a connector casing.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional method of casting an epoxy resin for insulating a wire cable from a connector casing. In the figure, the conventional method is to heat the epoxy resin 02 containing the non-metallic or metallic filler particles 05 to 60 to 100 ° C. to bring it into a molten state, and inject it into the metal casing 04 at room temperature for casting. Has been adopted. The end portion of the electric wire cable 01 is fixed in the metal casing 04.
An epoxy resin is cast in to insulate the metal casing 1 from the metal casing 04.

[0003]

By the way, as shown in FIG. 2, in the conventional method, since agitation occurs during casting, a large number of air bubbles 03 are generated. It could not be completely pulled out to the upper part, and easily solidified while remaining in the metal casing 04.

The epoxy resin 22 has a coefficient of thermal expansion similar to that of the metal casing 04 in order to prevent the generation of cracks 21 due to shrinkage during solidification. The particles 05 are mixed in the epoxy resin 06 of the matrix, but the particle size of the filler varies and the filler 0 having a large particle size due to the difference in specific gravity.
No. 5 was apt to settle to the lower part, and a layer 23 having no filler was apt to be formed on the upper side of the metal casing 04.

For this reason, there is a problem that cracks tend to occur due to contraction at the corners and upper layers where the cracks 21 originate from the bubbles 03 and the difference in thermal expansion coefficient is large.

The above-mentioned defects during casting are more likely to cause cracks to grow in a service environment in which temperature cycles are likely to occur, which deteriorates the insulating property and sealing performance required for this type of product and causes a problem in service quality. there were.

An object of the present invention is to provide a new epoxy resin casting method that solves the above problems.

[0008]

In order to achieve the above object, the method for casting an epoxy resin of the present invention is such that an ultrasonic vibration is applied while vibrating a casing body on a vibration table vibrating by ultrasonic vibration of several megahertz. It is characterized in that a molten epoxy resin containing a filler is cast from the upper part of the casing in a state of being preheated to 60 to 100 ° C. by a heater coil for heating arranged around the apparatus.

[0009]

According to the epoxy resin casting method of the present invention,
Due to ultrasonic agitation, internal bubbles generated by convection at the time of casting are easily moved to the surface portion due to vibration of the epoxy molten metal, and are easily removed.

Before casting the casing body, 60 to 1
Since it is preheated at 00 ° C., rapid cooling due to injection of epoxy resin is avoided, a sufficient time is taken for bubbles to escape to the surface, and bubbles are likely to escape.

Further, by vibrating ultrasonically, the filler can be evenly distributed up to the surface and the coefficient of thermal expansion can be made the same as that of the metal casing even after solidification, whereby cracks can be prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a case where an epoxy resin containing a graphite filler is cast in a molten state into an aluminum casing.
The electric wire cable 1 has its end fixed inside, and the casing 4 is placed in an ultrasonic vibration device 7 containing hot water 9 (60 to 100 ° C.) and excited by a vibration exciter 10 at several MHz. Shaken.

A heater 8 for heating is arranged all around the ultrasonic vibration device 7, and the casing 4 is preheated to 60 to 100 ° C. by the heater 8.

When the epoxy resin 2 is injected into the casing from above the aluminum casing 4 under the conditions of ultrasonic vibration and preheating, the epoxy resin is agitated by ultrasonic vibration.

As a result, the graphite filler 5 in the epoxy resin 2 is uniformly dispersed, and the bubbles 3 generated during casting are easily moved to the surface portion, and the bubbles can be removed well.

Further, since the casing 4 is always kept at 60 to 100 ° C. by the preheating by the heater 8, the gradual cooling effect works, and cracks and bubbles during solidification shrinkage can be completely prevented. In addition, 6 shows a matrix resin.

[0017]

As described above, according to the casting method of the present invention, the following effects can be obtained. (1) Bubbles, which has been a problem in the past, can be completely removed, and cracks originating from these bubbles are not generated, so the quality is significantly improved. (2) It enables uniform distribution of the filler required to make the thermal expansion coefficient of the epoxy resin equal to that of the metal casing by ultrasonic vibration, and for example, the graphite-based filler particles (particle size 10 to 15 μm) are all distributed. About 1 for epoxy cross section
By uniformly dispersing the filler so as to have an interfacial coverage of 5 to 30%, it is possible to prevent cracking due to solidification shrinkage of the epoxy resin.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for casting an epoxy resin according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a method of casting an epoxy resin according to a conventional technique.

[Explanation of symbols] 1 electric wire cable 2 epoxy resin 3 air bubble 4 aluminum casing 5 graphite filler 6 matrix resin 7 ultrasonic vibration device 8 heater 9 hot water 10 vibration device

Claims (1)

Claim: What is claimed is: 1. While vibrating the casing body on a vibrating table which vibrates by ultrasonic vibration of several megahertz, a heater heater coil arranged around the ultrasonic vibration device is used to
A method for casting an epoxy resin, characterized in that a filler-containing epoxy resin in a molten state is cast from the upper part of the casing in a state of being preheated to 0 to 100 ° C.