JPH01298752A - Sealing agent for conducting circuit - Google Patents

Abstract

PURPOSE:To absorb impacts from outside and protect parts, by constituting a sealing agent with a mixture of a main agent having epoxy resin as a base and containing an inorganic filler, and a hardener having an acid anhydride as a base and containing an inorganic filler. CONSTITUTION:A main agent comprises epi.bis-type epoxy resin as a base, and an inorganic filler added to it. And, a hardener comprises a denatured acid anhydride as a base, and an accelerating agent and an inorganic filler added to it. The said main agent and hardener are taken out and mixed by the mixing ratio(weight ratio) of 100pbw and 150pbw respectively. A sealing agent 2 like this is dropped so as to cover chip parts 4 such as ICs, capacitors, etc., sinks into the gaps between the parts, and hardens. This can protect the chip parts 4 themselves and conductive adhesive 5 from vibration and external force. In other words, physical protection becomes secure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an encapsulant for electrically conductive circuits that protects components of electronic component circuits, in particular physically and also electrically.

[Conventional technology]

A large number of chip parts including ICs (integrated circuits) and capacitors are arranged on an electronic circuit board, and a circuit board that achieves a desired purpose is constructed. This chip component is electrically connected to a conductive circuit using solder or conductive adhesive, but this connection alone is physically extremely fragile and is susceptible to external forces such as vibrations and shocks, moisture in the atmosphere, and Furthermore, it cannot electrically protect conductive circuits or chip components.

Therefore, in order to cover the chip components, it has been conventionally practiced to seal the chip components with a cured resin such as a silicone resin or a phenol resin.

[Problem that the invention seeks to solve]

However, conventional sealants have a high moisture absorption rate and have a large effect on the silver constituting the conductive circuit, causing problems such as corrosion and disconnection of the circuit. In addition, the flexibility is low, causing cracks and peeling on the base film, and the adhesion to the base film made of polyester or polyimide, which is the substrate, is also low, resulting in accidents such as peeling. There was also.

This invention aims to improve the drawbacks of the above-mentioned prior art.

[Means for solving problems]

In order to achieve the above object, the present invention is characterized in that it consists of a mixture of a base resin based on an epoxy resin and containing an inorganic filler, and a curing agent based on an acid anhydride and containing an inorganic filler.

[Embodiments of the invention]

This invention will be described in detail below.

The main ingredient is composed as follows. The base material is shrimp/bis type epoxy resin, and an inorganic filler is added to form the main resin. Then, the epoxy value was approximately 3.3 eq/kg, and the viscosity (25
°C) to approximately 40,000 cP.

The specific gravity (25°C) is set to about 1.5.

Further, the curing agent is constituted as follows.

Based on a modified acid anhydride, an accelerator and an inorganic filler are added to form a curing agent. And viscosity (25℃)
Approximately 9. 000 c P, specific gravity (25℃) approximately 1.3
shall be.

The above-mentioned main ingredient is mixed in a blending ratio (parts by weight) of 100 pbW, and the curing agent is mixed in the same proportion (<150 pbw). Then, the viscosity of the mixture becomes: 25°C: 21,000cP 40°C: 6,400cP 60°C: 1,800cP.

The pot life of this sealant is 8 hours at 25°C.

within

In addition, the gelation time is 80℃: 30 minutes 100°C: 15 minutes.

The following three examples can be given as the curing conditions.

1), 100°C/1 hour 2), 120°C/30 minutes 3), 150°C/15 minutes As shown in the drawing, the sealant 2 configured as in the above embodiment is used to seal ICs (integrated circuits), capacitors, etc. Apply the sealant 2 to completely cover the chip parts 4, and apply the sealant 2 to the gaps between the parts.
and cured according to the above-mentioned curing conditions.

This ensures the so-called physical protection that protects the chip component 4 itself and the conductive adhesive 5 from peeling accidents, that is, from vibrations and external forces.
By having a good value of 4.0XIO''ΩG, electrical insulation protection can be effectively achieved and the reliability of the product can be improved.

Furthermore, since the conductive circuit 6 made of conductive materials such as silver and copper dislikes moisture, it is required to be sealed with a material that has a low water absorption rate. 0.0
The base film 8 is extremely low at 8%, has little effect on silver and copper, can effectively prevent migration, and can effectively prevent disconnection of conductive circuits. It also has good adhesion to the surface and can improve the reliability of the product.

Furthermore, the sealant of this invention has a temperature of 27.0 at 25°C.
Since it is about 0.00 cP, it can be processed by screen printing, it can be applied to precision patterns, it can be mass-produced, and it has high technical and economical effects. Moreover, it has extremely good properties as a sealing agent for conductive circuits, without the inconvenience of covering chip components and causing them to become flattened and washed away.

Since the sealant of the present invention has the above-mentioned structure, it is rich in thixotropy, and after sealing, after the sealant has hardened, it is flexible and therefore absorbs external impact. , it can protect components.It also has the effect of having extremely good volume resistivity and breakdown voltage at high temperatures.

[Brief explanation of the drawing]

The drawing is a partially sectional side view illustrating the invention in detail. In the figure, 2 is a sealant, 4 is a chip component, 5 is a conductive adhesive, 6 is a conductive circuit, and 8 is a base film. Patent applicant: Abisare Co., Ltd. Agent: Yoshimi Nishi Tabe, patent attorney

Claims (1)

[Claims] 1. A sealing agent for conductive circuits comprising a mixture of a main agent based on an epoxy resin and containing an inorganic filler, and a curing agent based on an acid anhydride and containing an inorganic filler.