JPS6110201A - Resistance circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resistive circuit board that uses a polyphenylene sulfide substrate on which terminals and electrodes are insert-molded, and has a carbon-based resistive layer formed on the circuit by printing, and has excellent moisture resistance and heat resistance properties. be.

Conventionally, glazed resistors such as small hybrid ICs and resistor arrays have been manufactured by printing a glazed resistor paste in a predetermined pattern on a ceramic substrate and firing it at a high temperature of 800 to 950C. Glaze resistors such as these have excellent moisture resistance and heat resistance, but they are expensive resistance pastes and ceramics.

Since it requires a separate substrate and must be fired at a high temperature around 850C, the manufacturing cost is higher than that of carbon resistors.
In addition to being sticky, terminal materials also have drawbacks such as complicated work and low productivity. On the other hand, a resistor with a carbon-based resistance layer formed on a resin laminate has excellent moisture resistance, temperature characteristics,
・・In terms of heat resistance and other properties, it is far inferior to glazed resistors using ceramic or resin substrates, and especially paper phenol or glass fiber epoxy resin laminates are inferior to ceramic or resin substrates. In contrast, in the soldering process,
The resistance value changes greatly, and the board may be deformed or terminal defects may occur. Therefore, there is a strong demand for an inexpensive resistor circuit board that has excellent reliability, moisture resistance, and heat resistance.

The present invention solves the above-mentioned problems and provides a resistor circuit board that has extremely excellent moisture resistance and heat resistance, and is highly reliable.

The present inventors noted that in order to obtain an excellent resistive circuit board, there is a very close relationship between the composition of the resistor substrate and the composition of the binder of the resistive layer. As a result of research using a molded substrate and a carbon resistor whose binder is diallyl iso-7-talate resin, it was found that the electrical characteristics and reliability of the electrode section were significantly improved compared to conventional carbon resistors. Heading This is what has led to the present invention.

In the present invention, first, a highly crystalline polyphenylene sulfide resin molded plate into which metal terminals are inserted is used as a substrate. Since this polyphenylene sulfide resin has a low degree of polymerization and high fluidity, it can be used containing various fillers such as glass fiber and mineral fillers. In addition, it is extremely crystalline, and during molding, if the mold temperature is low, the degree of crystallinity is low, making it difficult to
A high-order diallylisophthalate prepolymer with inferior properties is dissolved in butyl carpitol, and tertiary-butyl perbenzoate is added thereto as a catalyst, and fillers such as carbon particles, boron nitride, and titanium oxide are thoroughly kneaded in a mixing roll mill. A resistive paste is thereby obtained. In this case, it is preferable to use a diallylinophthalate prepolymer that has been removed by fractional precipitation to a low weight of 10 to 3 oA. By printing this resistance paste on the insulating substrate and baking it, β polymer is converted to γ by addition polymerization of diallylisophthalate prepolymer.
At the same time as it changes into a polymer and hardens into a strong resin with a three-dimensional structure, the polyphenylene sarnoide on the other substrate also progresses in crystallization during the heating process and partially crosslinks at high temperatures to form a dense three-dimensional structure. It is thought that such a reaction occurs simultaneously in the resistive layer and the substrate during the heating process, forming a dense resistor, resulting in a resistor with excellent moisture resistance and heat resistance.

Embodiments of the present invention will be described below with reference to the drawings.

First, a predetermined number of metal terminal frames formed by press working as shown in Fig. 1 are embedded in glass fiber-containing polyphenylene sulfide resin (1) as shown in Fig. 2, and the molding temperature is 310 C ± 10 C1 mold temperature. 140r:
An insulating substrate is made by injection molding at ±1Or. (2) is the lead portion of the metal terminal, and (3) is the lead-out electrode portion of the circuit in which the tip portion of the metal terminal is exposed on the surface of the substrate. Next, diallyl isophthalate resin IIW (A) from which 25 units of low polymer were removed by fractional precipitation was dissolved in butyl carbitol, and carbon black (B) was added to the mixture to which tert-butyl perbenzoate was added as a catalyst. Resistance paste mixed with mineral filler (C) and kneaded with a roll mill (composition ratio A: 57%, B: 1)%, C: 32%
H) is printed in a desired circuit pattern on the insulating substrate (1) as shown in FIG. 3 and fired to form a carbon resistor (6), and a silver conductor (5 ) and a protective coat is applied over it. The sheet resistance of this resistor was 3Ω/hole. As shown in FIGS. 3 and 4, if necessary, metal pieces 4) may be embedded in the substrate during molding, or conductive processing may be performed using through holes, so that metal pieces 4) can also be formed on the back surface of the insulating substrate (1). It is also possible to increase the density by connecting it to other circuits.

The resistance circuit board manufactured as described above has very high reliability as a medium, and has i4 humidity characteristics such that the resistance value change rate after 72 hours is -2 at an ambient temperature of 40C and a relative humidity of 90 to 95%.
, 7%, temperature characteristics -30t? 1) 0 ppm/℃,
-40ppm/℃ for 85U, solder heat resistance is solder reflow oven (peak temperature 220-230tT, 20 seconds) When flowing K once, the resistance change rate is -0.8 inches When flowing 12 times, it is -1.3 inches there were. These values are close to the electrical characteristics of a glaze-based resistor, and are completely unobtainable with conventional carbon resistance circuit boards. In addition, a carbon resistor made of Evoquine-melamine resin as a binder on a paper phenolic resin laminate has extremely poor moisture resistance, and when a solder reflow test is performed, the board swells and deforms, resulting in changes in resistance and variations in resistance. It was too large to be put to practical use. Further, when a glass fiber-containing epoxy resin laminate was used as a substrate, the solder reflow test showed severe discoloration of the substrate and a large change in resistance value of 6 inches.

[Brief explanation of the drawing]

From FIG. 1, the fourth area is related to the present invention, and the first
FIG. 2 is a perspective view of a frame of metal terminals, FIG. 2 is a board in which metal terminals are embedded and integrally molded, and FIG. 3 is a perspective view of a resistive circuit board showing an embodiment of the present invention. FIG. 4 is a side sectional view and an enlarged partial view of the resistor circuit board. 1 piece polyphenylene sulfide insulating board 2 has metal terminal 3 at the tip of the metal terminal, circuit extraction electrode part 4 connects circuits on both the front and back sides of the board, metal piece 5 is silver conductive part 6 is carbon resistor part

Claims (2)

[Claims] (1) A resistive layer in a circuit formed on an insulating substrate with terminals and electrodes insert-molded using polyphenylene sulfide resin, whose main component is carbon-based particles and diallyl phthalate resin as a binder. A resistor circuit board characterized by: (2) Diaryl isophthalate resin is a low polymer 10 to 3
2. A resistor circuit board according to claim 1, wherein 0% by weight is removed by fractional precipitation.