JPS6112331A - Manufacture of thermo-setting resin laminated board having excellent punching workability - 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 [Industrial Field of Application] The present invention relates to a method for manufacturing a thermosetting resin laminate having excellent punching workability.

[Prior art]

Thermosetting resin laminates include phenolic resin laminates, epoxy resin laminates, unsaturated polyester resin laminates, etc. that are based on cellulose fiber paper or glass fiber nonwoven fabric. Conventional thermosetting resin laminated sales machines are still insufficient in terms of punching processability, especially the straightness and dimensional stability of the punched hole wall, and trouble-free automatic insertion and surface mounting of parts, uniform soldering. There is a strong desire to improve this characteristic from the viewpoints of ease of attachment and through-hole connection reliability.

In addition, with the recent development of electronic devices, printed circuit boards used in electronic devices are becoming more densely wired. Rationalization of production is progressing in areas such as production.

Under these circumstances, the requirements for laminates are that they must have excellent punching workability, dimensional stability, and electrical properties. Although it is strongly desired that the wall surface be straight and smooth when viewed, there has not yet been a sufficient laminate in this respect.

[Purpose of the invention]

The present invention has completed a thermosetting resin laminate with excellent punching workability and small dimensional change using a composite base material of aluminum hydroxide and specific fibers.

[Structure of the invention]

The present invention uses a prepreg in which a cellulose fiber base material or a mixed base material of cellulose fibers and synthetic fibers is impregnated with a thermosetting resin for the surface layer, and aluminum hydroxide, glass fiber, cellulose fiber, and synthetic fiber for the intermediate layer. This is a method for manufacturing a thermosetting resin laminate with good punching workability, characterized by using a prepreg in which a mixed base material is impregnated with a thermosetting resin.

In the present invention, examples of thermosetting resins include phenol resins, epoxy resins, polyester resins, etc., and coupling agents, pigments, dyes, inorganic fillers, etc. can be mixed into these resins. Prepreg is obtained by the usual method, but in this case, water-soluble low-molecular-weight phenolic resin,
Cellulose fiber base materials, cellulose fibers and synthetic fibers, and aluminum hydroxide/glass fibers/cellulose fibers/synthetic fiber mixed base materials can also be treated in advance with methylolmelamine resin or the like. The cellulose fiber base material used for the surface layer is generally a raft fiber or a linter fiber. Similarly, in the case of a mixed base material of cellulose fibers and synthetic fibers, the cellulose fibers may be kraft fibers or linter fibers, and the synthetic fibers may be aromatic or aliphatic polyamide fibers, polyester fibers, polyvinyl acecool fibers, phenol fibers, etc. The reed is not particularly limited, but polyester fiber is preferred. Furthermore, the diameter of synthetic fibers is 2 to 6 μm,
The length is preferably 3 to 12 cm, and the mixing amount is preferably 2 to 8%.

It is also effective to treat these base materials with a coupling agent in a previous step. The mixed paper base material used for the middle layer is a specially formulated aluminum hydroxide mixed paper fiber base material,
That is, it is a mixture of cellulose fibers such as kraft fibers and linter fibers with aluminum hydroxide powder, glass fibers, and synthetic fibers. The type of aluminum hydroxide powder to be mixed is not particularly limited, but it is preferably one with a gibbsite crystal structure that has a high thermal decomposition temperature, and the average particle size is preferably 30 μm or less, more preferably 10 μm or less. Further, the mixing amount is preferably 60 to 90%, and if it is less than 59%, the flame resistance effect tends to decrease.

The diameter of the glass fibers to be mixed is 2 to 6 μm, and the length is 3 to 12
m, and the mixed paper amount is preferably 2 to 15 qb, more preferably 10 qb or less. The synthetic fibers to be mixed include aromatic or aliphatic polyamide fibers, polyester fibers, polyvinyl acetal fibers, phenol fibers, etc., but are not particularly limited, but polyester fibers are preferred. The synthetic fiber preferably has a diameter of 2 to 6 μm, a length of 3 to 12 μm, and a mixed amount of 2 to 8 pieces.

The prepregs made of the base material thus obtained are placed in the surface layer and the intermediate layer, respectively, and heated and pressure molded by a conventional method. The thus obtained laminate has excellent punching workability and good dimensional stability in the plane direction and the thickness direction.

〔Effect of the invention〕

The thermosetting resin laminate obtained by the method of the present invention has the following features.

(1) Excellent punching workability, especially straight and smooth hole walls. Therefore, there is no need for the lead wire to get caught when inserting the component, and insertion troubles are reduced. Furthermore, since the gap between the inserted lead wire and the hole wall is constant, a uniform solder finish is possible, and the number of defective soldering spots after the component is mounted is extremely reduced.

(2) Excellent dimensional stability. In other words, it is suitable for silver through-hole printed resistance boards and general through-hole plating boards because it has good positional accuracy required for automatic insertion and surface mounting printed wiring circuit boards, and has small dimensional changes in the board thickness direction. .

[Example] Example 1 Kraft paper was impregnated and dried with a prepreg having a phenolic resin content of 4496 as the surface layer, and aluminum hydroxide mixed paper (mixing ratio: aluminum hydroxide/glass fiber/cellulose fiber/ Polyester fiber = 80/4
/14/2), impregnated and dried prepreg with a phenol resin content of 39% is placed in the middle layer, and 3
Combined with 5μ electrolytic copper foil, 170℃, 80kf/d
Heat and pressure molding was performed for 90 minutes at
A single-sided copper-clad laminate was obtained. Its properties are shown in Table 1, and it shows that it has excellent punching workability, particularly the amount of shrinkage of the punched hole is very small, and a linear hole wall shape is obtained. Furthermore, it was an excellent laminate with excellent dimensional stability, soldering heat resistance, and insulation resistance.

Example 2: 45% epoxy resin in kraft fiber and synthetic fiber mixed paper
The impregnated and dried prepreg is used as the surface layer as shown in -
Impregnated aluminum hydroxide mixed paper (mix ratio: aluminum hydroxide/glass fiber/cellulose fiber/polyester fiber = 80/4/14/2) with 42% epoxy resin and dried prepreg as the middle layer. Place a 35μ electrolytic copper foil on one side and heat at 170℃7.
Heat and pressure molding was performed for 90 minutes at 0 kf/crA to obtain a single-sided copper-clad laminate with a thickness of 1.6 mm. Table 1 shows its characteristics.
As shown in Figure 2, it was an excellent laminate with excellent punching workability, good soldering heat resistance, and good insulation resistance.

Comparative Example 1 The kraft paper prepreg used for the surface layer in Example 1 was combined alone with 35μ electrolytic copper foil, and heated and pressed under the same conditions as Example 1 to form a single-sided copper sheet with a thickness of 1.6 m+. A stretched laminate was obtained. The characteristics are shown in Table 1, and the dimensional stability and punching workability were inferior to those of the examples, and in particular, the punched holes had a large amount of shrinkage and a straight hole wall shape was not obtained.

Comparative Example 2 A prepreg made by impregnating and drying epoxy resin on kraft paper was combined alone with 35 μm electrolytic copper foil, and heat and pressure molded under the same conditions as Example 2 to produce a single-sided copper-clad laminated sheet with a thickness of 1.6 m+. Got the board. The characteristics are shown in Table 1, and the dimensional stability and punching workability were inferior to those of the examples, and in particular, the amount of punched hole shrinkage was large, and a straight hole wall shape was not obtained.

The test method is as follows.

(1) Soldering heat resistance According to JIS C-6481.

(2) Punching processability Surface, end face, hole: According to ASM-617 (punching temperature 60°C).

(3) Dimensional stability (heat shrinkage rate) It was expressed as the rate of change with respect to the initial dimension after constant heating from room temperature to 250°C at 10°C/min and cooling.

(4) Conduction resistance change rate JIS C-50129-3 Thermal shock (high temperature immersion)
The conduction resistance value was expressed as a rate of change.

Cycle conditions ° 260℃ oil 5 seconds to warm triethane 20 seconds (5) Insulation resistance According to JIS C-6481.

Claims (1)

[Claims] For the surface layer, a prepreg made of a cellulose fiber base material or a mixed base material of cellulose fiber and synthetic fiber impregnated with a thermosetting resin is used, and for the middle layer, aluminum hydroxide, glass fiber,
A method for producing a thermosetting resin laminate with good punching workability, characterized by using prepreg in which a base material made of a mixture of cellulose fibers and synthetic fibers is impregnated with a thermosetting resin.