JPH03287668A - Highly thermally conductive resin composition - Google Patents

Abstract

PURPOSE:To increase thermal conductivity by compounding a heat-resistant thermoplastic resin with a polyimide resin with is liq. at room temp. and a highly thermally conductive inorg. filler. CONSTITUTION:A heat-resistant thermoplastic resin having a flow starting temp. of 200 deg.C or higher and excellent high-frequency characteristics (e.g. a polysulfone) is compounded with 5-50wt.% polyimide resin which is liq. at room temp. (e.g. a soln. of a polyamideimide resin in an org. solvent) and 10-50wt.% at least one highly thermally conductive inorg. filler having a particle diameters of 1-30mum and selected from the group consisting of BN, AlN, and MgO.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a resin composition with excellent thermal conductivity, which is particularly suitable for use as an insulating material for metal-based printed circuit boards, electronic component encapsulating materials, etc. The present invention relates to a resin composition.

(Prior art and its problems) In recent years, there has been a demand for printed circuit boards that can effectively dissipate heat generated from electronic components such as IC chips and power transistors. A metal-based printed circuit board is known. As an insulating material used in such metal-based printed circuit boards, it is known that an insulating resin contains a highly thermally conductive inorganic filler such as alumina, which has excellent thermal conductivity.

However, depending on the type of resin used for the insulating material, the inclusion of the above-mentioned highly thermally conductive inorganic filler may dramatically reduce fluidity during molding, resulting in poor adhesion to other materials such as metal plates. Since the strength decreases, the content of the inorganic filler has to be lowered, and as a result, it is difficult to obtain a material having a predetermined thermal conductivity.

An object of the present invention is to provide a resin composition having excellent thermal conductivity by using a heat-resistant thermoplastic resin such as polyether ethergetone or polyphenylene sulfide, which has particularly excellent high frequency properties.

(Means for Solving the Problems) In order to achieve the above object, the resin composition of the present invention uses a specific inorganic filler and a polyimide resin in combination, and the gist thereof is exists in a highly thermally conductive resin composition formed by adding a polyimide resin that is in a solution state at room temperature and a highly thermally conductive inorganic filler to a heat-resistant thermoplastic resin.

Heat-resistant thermoplastic resins used in the present invention include those having a flow start temperature of 200°C or higher, high-frequency hydride, polyetheretherketone, thermoplastic fluororesin, polyetherimide, polyethersulfone, polyamideimide,
Examples include polyphenylene oxide.

It is necessary to add a polyimide resin in a solution form at room temperature and a highly thermally conductive inorganic filler to the heat-resistant thermoplastic resin mentioned above, and the polyimide resin in a solution form is a polyamide-imide resin dissolved in a normal organic solvent. Similarly, a bismaleimide triazine resin or the like dissolved in an organic solvent in the form of a solution at room temperature is used. The content of the polyimide resin may be determined as appropriate depending on the type of inorganic filler used, and it is usually added in an amount of 5 to 50% by weight based on the entire composition.

Next, as the highly thermally conductive inorganic filler, various inorganic fillers with excellent thermal conductivity can be used, but one or more types selected from poron nitride, aluminum nitride, and magnesium oxide are particularly preferred. Can be used. As boron nitride (hereinafter referred to as rBNJ), those having a particle size of about 1 to 30 μm can be suitably used.

In addition to the above BH, aluminum nitride (rAjNJ
) and/or magnesium oxide (hereinafter referred to as "MgO"), it is possible to improve not only thermal conductivity but also adhesion to metal materials such as metal plates. The above-mentioned inorganic filler may be surface-treated with a surface treatment agent such as a silane coupling agent in order to improve its affinity with the resin. The content of the highly thermally conductive double filler is preferably in the range of about 10 to 50% by volume based on the entire composition from the viewpoint of thermal conductivity and dispersibility.

In the composition of the present invention, the presence of the solution polyimide resin allows the inorganic filler particles to be distributed in all directions so as to fill the gaps between the particles of the dispersed heat-resistant thermoplastic resin in powder form. It is estimated that as a result, it becomes possible to improve thermal conductivity. In this case, in a composition in which no polyimide resin is added, it is difficult to achieve uniform performance because the resin melts and lines up in the direction of the inorganic filler or along the melt flow.

In addition, when the composition of the present invention is applied to a metal plate or the like as an insulating material, each component is mixed, the viscosity is adjusted with a solvent, etc., and then applied using a roll coater or the like, and dried and cured. It can be easily obtained by

The present invention will be explained below with reference to Examples.

(Example) Polyetheretherketone (PEEK) was used as a heat-resistant thermoplastic resin, and BN and ANN surface-treated with a silane coupling agent were used as highly thermally conductive inorganic fillers.
and MgO, and the mixing ratio (weight) is BN:
AjN:Mg0=3:2:5). Furthermore, a solution of polyimide resin (polyamide-imide resin/dimethylformamide) is added to the total composition in an amount of 40% by weight, heated to B-stage, and then made into a powder. Pressure-form it into a plate shape.

The thermal conductivity of the obtained plate-shaped body was measured.

Curve 1 in FIG. 1 shows the results of measurement of the inorganic filler used here by changing the amount added without changing the mixing ratio.

In addition, as a comparative example, the above PEEK and inorganic filler were used without using polyimide resin, and the thermal conductivity after melting and cooling was measured by varying the amount of inorganic filler added. The results are shown as curve 2 in Figure 1. Show me.

From FIG. 1, it can be seen that according to the composition of the present invention, the thermal conductivity is improved by the addition of the polyimide resin even if the content of the inorganic filler is the same.

(Effects of the Invention) As described above, the resin composition of the present invention has excellent thermal conductivity, and therefore has great utility as an insulating material for metal-based printed circuit boards.

[Brief explanation of drawings]

FIG. 1 is a drawing showing the relationship between inorganic filler content and thermal conductivity.

Claims (1)

[Scope of Claims] 1. A highly thermally conductive resin composition obtained by adding a polyimide resin in a solution state at room temperature and a highly thermally conductive inorganic filler to a heat-resistant thermoplastic resin. 2. The highly thermally conductive resin composition according to claim 1, wherein one or more types selected from boron nitride, aluminum nitride, and magnesium oxide are used as the highly thermally conductive inorganic filler.