JP2002093602A - Electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem, in which a sheathing film is hard to be formed on a varistor when a varistor is formed of flame-retardant material and increased in the amount of flame-retardant material used, so as to turn the varistor incombustible. SOLUTION: The resin content of sheathing material is set at 1 to 5 wt.%, and inorganic filler contained in the sheathing material is bound together with inorganic glass matter, formed of alkoxysilane whose main component is Si.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component having an improved exterior material.

[0002]

2. Description of the Related Art In recent years, in order to reduce the weight of electronic devices and electric devices, the use of plastics, including housings, has increased.
Due to miniaturization, the density of component mounting is increasing. If such a situation progresses and the electronic component burns out, there is a risk that the device itself will burn.
An electronic component that may be burned out is, for example, a voltage non-linear resistor (hereinafter referred to as a varistor). Varistors used to protect other electronic components and equipment from external or internal surges will break and short-circuit if they absorb a surge that exceeds the limit of absorbed energy.
As a result, the varistor may generate heat and the exterior material may burn. The exterior of such a varistor is generally formed of a resin component such as an epoxy resin and an inorganic filler component, and combustion of the exterior material is caused by combustion of a resin component such as an epoxy resin.

For this reason, a flame-retardant resin material is used for the exterior of the varistor. For example, an epoxy resin containing Br or Sb is used as a flame retardant. However, since these epoxy resins are flame-retardant and not non-flammable, they may be ignited by the heat generated by the varistor and may continue burning until the combustible components in the resin are exhausted.

In order to make the exterior nonflammable, Br, Sb
When the amount of the flame retardant is increased, there is a problem that the heating flow rate of the resin itself is reduced, and it becomes difficult to form an exterior film.

[0005]

As described above, in the prior art, when a varistor is made non-combustible, it is difficult to use a flame-retardant material and increase the number of flame-retardants. Had a disadvantage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides an electronic component having a non-flammable exterior of an electronic component such as a varistor, and having an exterior having no problem in formation and exterior strength. The purpose is to.

[0007]

According to the present invention, there is provided an electronic component which is packaged with a packaging material containing an inorganic filler as a main component.
It is not less than t% and not more than 5 wt%, and the inorganic filler in the exterior material is bonded by an inorganic vitreous material generated from alkoxysilane containing Si as a main component.

According to the electronic component of the present invention, the incombustibility of the exterior material is realized by reducing the resin component, which is the flammable component of the exterior material, to 5 wt% or less, and the inorganic filler in the exterior material contains Si. By joining with an inorganic vitreous material formed from alkoxysilane as a main component, there is no problem in the formation of the exterior and the exterior strength even when the resin component is 1 to 5 wt%.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electronic component according to the present invention is manufactured as follows using a varistor as an example. Electrodes are printed on both sides of a sintered body containing zinc oxide as a main component with a margin, and baked to form a varistor element. Further, a lead wire is soldered to this electrode. An element having a lead wire soldered to this electrode is immersed in a liquid exterior forming material whose main component is an inorganic filler to perform exterior coating. The element on which the package is formed in this way is immersed in liquid alkoxylan, and the inorganic filler in the package is bonded with glass.

Here, in order to make the varistor incombustible,
It is necessary to reduce the content of the resin component, which is a combustible component, in the exterior forming material to a value equal to or lower than the combustion limit value. If the weight ratio of the resin component composed of organic matter in the exterior material is 5% or less, such incombustibility can be realized. However, if the content of the resin component is reduced, the strength of the exterior is reduced, and during transportation or mounting, There is a problem that cracks and chips on the exterior occur.

Therefore, the exterior is impregnated with liquid alkoxylan containing Si as a main component, and the inorganic filler is bonded with glass, so that the amount of the resin component in the exterior forming material can maintain at least the strength of the exterior. However, when the content of the resin component is less than 1 wt%, a decrease in the exterior strength cannot be prevented even with the use of alkoxysilane.

[0012]

EXAMPLES Specific examples will be described below.

Φ10 mm containing zinc oxide as a main component and magnesium oxide, bismuth oxide, cobalt oxide, etc.
An electrode having a diameter of 8 mm was printed on both sides of the sintered body with a margin and fired. A lead wire of φ0.8 mm was soldered to this electrode. The element to which the lead wire is soldered is immersed (2 seconds) in a liquid exterior forming material containing an inorganic filler as a main component, pulled out of the liquid, and dried at room temperature (5 seconds).
Further, it is immersed (2 seconds) in the liquid exterior forming material, pulled out of the liquid and dried at room temperature (20 seconds), further immersed in the liquid exterior forming material (2 seconds), pulled out of the liquid and dried at normal temperature (1 second).
2 hours) and cured at 150 ° C. for 1 hour to form an exterior. The element having the exterior thus formed was immersed in liquid alkoxylan for 20 seconds, dried at room temperature for 12 hours, and
The composition was cured at 0 ° C. for 60 minutes, and the inorganic filler in the exterior was bonded with glass.

In the above method, a flammable resin component in the liquid packaging material, a phenol resin as an inorganic filler component, an inorganic thixotropic additive as an additive, and a mixed solvent of methyl ethyl ketone / methyl alcohol as a solvent are added. With respect to those used, the nonflammability was confirmed by changing the ratio of the flammable resin component to the inorganic filler component as shown in Table 1 below. Confirmation of noncombustibility is UL (US safety standard)
A flame contact combustion test was performed by the method specified in 1414, and the presence or absence of external combustion was confirmed. As for the exterior strength, the occurrence of cracks in the exterior part when the lead wire was bent at 90 degrees when the lead wire came out of the resin coating portion was confirmed with the varistor element fixed.

[0015]

[Table 1]

As can be seen from Table 1, when the resin component in the exterior exceeds 5 wt%, exterior combustion occurs. In addition, when the resin is not immersed in the alkoxylan and there is no bonding of the inorganic filler due to the formation of glass, if the resin component in the exterior is 5 wt% or less, the exterior strength is reduced. On the other hand, when the inorganic filler is bonded by immersion in an alkoxylan and glass formation, a reduction in exterior strength can be prevented even when the resin component is 5 wt% or less. However, when the resin component is less than 1% by weight, a decrease in exterior strength cannot be prevented even with the use of alkoxysilane, and cracks and the like of the exterior occur. Therefore, when the resin component is 1
A varistor having a non-flammable sheath in a range of not less than 5 wt% and not more than 5 wt% and having no problem with the outer strength can be manufactured.

[0017]

As described above, according to the present invention, it is possible to supply an electronic component having a varistor having a non-flammable exterior, and having an exterior with no problem in the formation and strength of the exterior.

The present invention is not limited to the above embodiment. The same effect can be obtained by using epoxy resin, silicone resin or the like as the resin of the exterior material other than phenol. It is. The inorganic filler is not limited to silica, but may be any nonflammable and insulating inorganic material. Furthermore, the present invention relates to the exterior of the electronic component, other steps can be appropriately selected,
The present invention is not limited to varistors, and can be applied to other electronic components that are covered with a resin, such as a ceramic capacitor.

Claims (1)

[Claims] 1. An electronic component packaged with a packaging material containing an inorganic filler as a main component, wherein the content of the resin component of the packaging material is 1% by weight or more and 5% by weight or less, and the inorganic filler in the packaging material is An electronic component, wherein the electronic component is joined by an inorganic vitreous material generated from an alkoxysilane containing Si as a main component.