JPH04142338A - Preparation of laminated sheet - Google Patents

Abstract

PURPOSE:To improve punchability, heat resistance, humidity resistance, etc., by impregnating a cellulose fiber substrate with a water-sol. varnish, drying the substrate, impregnating it with a thermosetting resin varnish, drying the substrate, and laminating and molding the resulting prepreg. CONSTITUTION:A cellulose fiber substrate, i.e. a paper substrate (e.g. kraft paper), is impregnated with a water-sol. varnish, pref. a water-sol. phenol or melamine resin warnish, thermally dried under a reduced pressure at 60 deg.C or lower, impregnated with a thermosetting resin varnish, pref. a drying oil- modified phenol resin (e.g. a resol phenol resin 35% modified with tung oil), and dried to give a prepreg. Required pieces of the prepregs are laminated and thermally pressed to give a laminated sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a laminate having excellent punching workability, moisture resistance, silver migration resistance, electrolytic corrosion resistance, and heat resistance.

[Conventional technology]

Recently, as electronic devices have become lighter, shorter, and smaller, 1.78
There is a need for an MCL that can punch out XC holes and connector holes of m11 pitch and 1.5051 jl pitch at room temperature.

Ki! has traditionally been used to improve punching workability. Flexibility of lubricant or use of paper base material with low elasticity is carried out.

On the other hand, as electronic devices become more multi-functional and highly reliable, the use of copper-plated through-holes and silver-paste through-holes in paper-based laminates has progressed, and high reliability has become necessary. Ta. % silver-resistant Maidareshi! There is a need for laminates with excellent electrical resistance and electrical corrosion resistance.

In order to improve resistance to scissor migration and electrolytic corrosion, a conventional method has been used in which paper substrates are impregnated with water-bathable phenolic resins, water-soluble melamine resins, etc. and dried to improve moisture resistance.

In addition, surface coating is performed in response to higher density, but if the heat resistance is low, swelling (n) and warping (t) will occur in the base plate. To improve heat resistance, make the resin heat resistant and add a heat resistant component.

In addition to conventional countermeasures, making the resin more flexible will improve punching workability and major crack problems in ICs, etc., but it will improve heat resistance, silver migration resistance, electrolytic corrosion resistance, and resistance to corrosion. Solvent compatibility & deterioration.

When a low elastic group @ upper phase is used, punching workability improves, but warpage % and dimensional properties decrease.

In the method of treating the paper base material with water-bathable phenol resin or water-bathable melamine resin, it is necessary to dry it to remove water, etc. will improve. However, drying causes excessive hardening and reduces single-stroke workability.

In addition, in the conventional method of improving heat resistance, 1.
The method of adding a component with a high heat content W4 temperature change has the problem that the laminate becomes hard and the punching workability decreases.

[Problem to be solved by the invention]

Under the above technical circumstances, the inventor of the present invention has deeply studied the method of treating paper-based shavings with a water-soluble enol resin or water-soluble melamine resin, that is, the method of water-soluble treated varnish, and has obtained satisfactory results. .

The present invention provides a laminated material with excellent punching workability, heat resistance, moisture resistance, migration resistance, and electrolytic corrosion resistance.
purpose.

〔assignment? Means to solve]

In order to achieve the above objectives, unexploded f3A was impregnated with a water-bathable 2-enol resin or water-bathable melamine resin varnish, that is, a water-soluble treated varnish, on a paper base material, and then heated in a reduced pressure atmosphere.
This is a method for manufacturing a laminate in which prepregs obtained by heating and drying to 0° C. or lower, further impregnating and drying with a thermosetting resin varnish, and then stacking the obtained prepregs and molding them under heat and pressure.

The paper base material to be used may be linter paper, kraft paper, etc., but a lurose fiber base material may be used.

Water 1@-based phenolic resin and water-soluble melamine S + fat are
Taking advantage of its affinity with cellulose, a solvent is selected for impregnation step 5 in a solution state that has good affinity with cellulose.

Solvents are water, methanol, acetone, methyl ether ketone, toluene, styrene, DMFSTHF', DMSO
Of course, it can be used alone or as a mixture.

After the above water-soluble resin is dissolved in the above solvent, the varnish gold is impregnated with the above cellulose-based base odor, the solvent r is removed, and the K is heated at 60°C or less in a reduced pressure atmosphere, and the degree of vacuum is 200°C.
rr or less is better.

Thermosetting resin Q resin, 2-enol resin, epoxy resin,
Unsaturated polyester resin etc., but thermosetting resin? It is also good to modify it and make it flexible. % drying oil-modified phenol A fat is good. The flexibility should be increased to the extent that heat resistance is not reduced. These include modified materials such as Q-process, drying oil, polyester, polyether, and epoxy-7-polybutadiene.

The above thermosetting resin is made into a varnish, impregnated into a base material treated with a water-soluble varnish, and heated by the usual method (F).
(Solvent removal) LC resin is made into gloves. The required number of prepreg sheets thus obtained are molded under heat and pressure once to obtain seven laminates. A steel laminated sheet can be obtained by rubbing it with a steel foil in a conventional manner, and further processed to form a printed wiring board 1r.

[Effect]

Impregnating a cellulose fiber with a water-soluble 2-enol resin or a water-soluble melamine resin takes advantage of their strong mutual affinity. Therefore, since it is well impregnated with the base material and forms a good resin film at ℃, it shows sufficient moisture resistance except for the solvent used. As a result, the scissors migration resistance and the electrolytic corrosion resistance are improved, and at the same time, the resin skin gI4 improves the impregnation of the thermosetting resin.

Conventionally, there was no consideration given to the heating process in J5, which is heated to 150°C, except for the above-mentioned solvents. Therefore, the resin film formed on all surfaces of WII becomes hard and brittle and has poor punching workability.

In the present invention, the conditions for forming the skin layer are 60°C or less under reduced pressure, so the film is flexible without over-hardening.
It has the effect of improving punching workability because of its retention.

Also, as will be described later in Examples of the present invention and Comparative Example 1r, when comparing the soldering heat resistance of the two, the Examples are clearly better. Both were used under the same flexible thermosetting resin R1 size conditions,
It can be said that the water-soluble resin treatment of the present invention has improved heat resistance.

〔Example〕

After soaking kraft paper with water-soluble phenolic resin,
It was dried at 50° C. in a reduced pressure atmosphere of torr to give a resin layer amount of 16 to 25%. Furthermore, the resin was impregnated with 1 liter of resol phenol with a tung oil modification rate of 65%, and the measured layer amount of the resin was 4.
8 to 60% and dried again to obtain 8 sheets of prepreg and adhesive properties @WJ? ? 3. Sweeten 1. Heat and pressure mold to 1.6a.
Obtained a double-sided steel-clad loading dock. Its properties' (l - shown in Table 1).

(Comparative example) Kraft paper was impregnated with water-bathable 2-enol resin r and heated at 150°C.
After drying it, it was made into a ryo-en doji-ku/il plate in the same manner as in the previous example. Its characteristics are shown in Table 1.

(Test) (1) Punching workability was determined by using a laminate plate T80 ton press and punching at 20°C with a hole pitch of 1.781!111. There were no cracks, separation, or confession, which was good ○, slightly bad △ , indicated as defective x.

(2) Soldering heat resistance was in accordance with JIS C6481.

(3) Moisture absorption rate is a value measured at 121°C, 2.2 atm, and 8 hours.

(4) Insulation resistance between lines after treatment with applied voltage of 50V, 40℃, 90% RHT + 000 hours between lines passed through 10 km of through holes filled with silver paste for silver migration resistance. I measured my feet.

Table 1 [Effects of the Invention] As is clear from the data shown in Table IK, the method of the present invention has improved punching workability, soldering heat resistance, moisture absorption rate, and silver resistance when compared with the comparative example using the conventional method. Is it possible that the mushroom properties of Migraci become a horizontal layer that is superior to that of china clay? confirmed.

〜、−ノ.

Claims (1)

[Claims] 1. After impregnating a cellulose fiber base material with a water-soluble treated varnish, it is heated and dried at 60°C or less in a reduced pressure atmosphere, and then the prepreg obtained by impregnating and drying a thermosetting resin varnish is laminated and heated and pressure molded. A method for manufacturing a laminate, characterized by: