JPS6147703A - Resin composition for coating electronic part - Google Patents

Abstract

PURPOSE:To provide the titled composition containing a photosetting resin and a fibrous filler, and useful for the coating of an axial-type electronic parts resistant to chipping. CONSTITUTION:A composition for the coating of an electronic part and containing a photosetting resin (e.g. epoxy acrylate, vinyl chloride, styrene, etc.) is compounded with a fibrous filler (e.g. glass fiber, asbestos fiber, cotton fiber, etc.). The amount of the filler is preferably 2-40pts.wt. per 100pts.wt. of the photosetting resin. EFFECT:When the main body of an electronic part 2 is coated with the above resin composition, a high coating strength can be attained owing to the fibrous filler, and there is no cracking of the coating 1 even if the load wire 3 is bent in complicate form.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a resin composition used for coating electronic (electrical) parts such as capacitors, diodes, and transistors.

[Background technology]

BACKGROUND ART Electronic components (elements, etc.) such as capacitors are coated with a resin composition for moisture-proof insulation. When a resin composition containing a photocurable resin is used, it is usually cured by irradiation with ultraviolet rays for several seconds to several minutes, resulting in a marked improvement in productivity.

However, in the case of an axial type electronic component in which the lead wire protruding from the main body is bent freely and set on a board etc., as shown in FIG. However, when the lead wire 3 is bent, the covering 1 often breaks. That is, as shown in FIGS. 2 and 3, since the lead wire 3 is often bent into a complicated shape, the area around the base of the lead wire 3 (at the interface between the lead wire and the coating) A great force is added,
As shown in FIG. 4, chipping frequently occurs in the portion of the coating (2) surrounding the base of the lead wire 3.

[Purpose of the invention]

The present invention was made in order to solve such problems, and an object of the present invention is to provide a coating resin composition that is less likely to cause chipping even when used for coating axial type electronic components. It is said that

[Disclosure of the invention]

The inventors have conducted repeated research focusing on a resin composition for covering electronic components containing a photocurable resin. As a result, they discovered that it is sufficient to include a fibrous filler, and have now completed this invention.

Therefore, the gist of the present invention is a resin composition for covering electronic parts containing a photocurable resin, which is characterized by containing a fibrous filler. The present invention will be explained in detail below.

Here, as the photocurable resin, epoxy acrylate, urethane acrylate, melamine acrylate, vinyl chloride, styrene, methyl acrylate, methyl methacrylate, methyl vinyl ketone, unsaturated polyester resin, etc. are used.

If necessary, a photopolymerization initiator, a diluent, etc. are used for purposes such as adjusting viscosity. For example, in the case of epoxy acrylate, urethane acrylate, melamine acrylate, etc., benzyl dimethyl ketal, benzophenone, benzoquinone, or acetophenone is used as a photopolymerization initiator, and ethylene glycol diacrylate (which has a diluting effect) is used as a diluent. )
etc. are used. In addition, in unsaturated polyester resin,
Diphenyl disulfide or the like is used as a photopolymerization initiator, and for methyl methacrylate, benzoin or the like is used as a photopolymerization initiator.

The fibrous filler is not particularly limited in type or shape, and includes, for example, inorganic fibers such as glass fibers and asbestos fibers, nylon fibers, and Tetron fibers.

Vinylon fiber, phenolic resin fiber (cationic fiber)
Synthetic organic fibers such as, silk fibers, cotton fibers, and other natural fibers are used. The content of the fibrous filler is preferably 2 to 40 parts by weight based on 100 parts by weight of the photocurable resin. ``In addition to the fibrous filler, the resin composition may also contain pigments and other fillers. Further, a thermal polymerization initiator such as a peroxide or a metal salt may be included so that photocuring, heat curing, or room temperature curing can be used in combination.

Since the resin composition according to the present invention contains a fibrous filler, it has high strength when cured.

Therefore, there is less risk of chipping.

Next, Examples and Comparative Examples will be described.

The raw materials were mixed in the proportions shown in Table 1 to obtain resin compositions for covering electronic components of Examples 1 to 5 and Comparative Examples. However, ethylene glycol diacrylate was used as a diluent monomer, and benzyl dimethyl ketal was used as a photopolymerization initiator (see the margin below). Using the resin compositions of Examples 1 to 5 and comparative examples, the following procedure was carried out. The strength against chipping was investigated. That is, first, each resin composition was used to form a coating 6 on a silicone tube 4 with a lead wire 5 passed through it, as shown in FIG. A silicon tube with lead wires passed through it was used as a substitute for electronic parts. Each resin composition was first exposed to ultraviolet light with an intensity of 80 W/cm.
It was irradiated and cured for the time shown in the table. After this, the fifth
As shown in the figure, bend the lead wire 5 at a nearly right angle at a position A, which is 5 lengths (length a in the figure) from the coating 6 of the lead wire 5. I rotated the tip. The strength of the coating against chipping was examined by counting the number of rotations until the coating was chipped, with 360° rotation being counted as one rotation. The results are also shown in Table 1. In Table 1, ◯ indicates pass and × indicates fail.

Table 1 shows that the coatings obtained from the resin compositions of Examples 1 to 5 have greater strength against chipping than the coatings obtained from the resin compositions of Comparative Examples.

〔Effect of the invention〕

The resin composition for coating electronic components according to the present invention is a resin composition for coating electronic components containing a photocurable resin, and since it contains a fibrous filler, it can also be used for coating axial type electronic components. There is little risk of chipping.

[Brief explanation of the drawing]

Figure 1 is a cutaway side view of an electronic component whose main body is covered with a coating, Figure 2 is a side view of the electronic component with its lead wires bent, and Figure 3 is a side view of the electronic component with the lead wires bent. Fig. 4 is a side view of the same electronic component/product with the coating cut away to show how the coating is chipped, and Fig. 5 is a determination of the strength against chipping. Agent Patent Attorney Takehiko Matsumoto Figure 1 Figure 3 Figure 4 Figure 5 An explanatory diagram of the law

Claims (3)

[Claims] (1) A resin composition for covering electronic parts containing a photocurable resin, which is characterized by containing a fibrous filler. (2) The content ratio of the fibrous filler is 10% of the photocurable resin.
2. The resin composition for coating electronic components according to claim 1, wherein the resin composition is used in an amount of 2 to 40 parts by weight relative to 0 parts by weight. (3) Claims in which the fibrous filler is at least one type selected from the group consisting of glass fiber, asbestos fiber, nylon fiber, Tetron fiber, vinylon fiber, phenol resin fiber, silk fiber, and cotton fiber. The resin composition for coating electronic components according to item 1 or 2.