JPH04163005A - Base material for prepreg - Google Patents

Abstract

PURPOSE:To make favorable infiltration of resin in base material possible and consequently obtain prepreg having uniform external appearance by a method wherein glass fabric base material is coated with deaeration-treated surface treating agent. CONSTITUTION:As surface treating agent, silane coupling agent such as aminosilane, epoxysilane, styrene silane and the like can be used. As base material, glass fabric or the like is preferably used. As the deaerating method of surface treating agent, among the heating under vacuum or either one of heating and evacuation under the state that porous body such as zeolite is included, gas separation by means of reverse osmosis through a semipermeable membrane, vacuum deaeration treatment or the like, proper method is selected for application. In order to coat the base material with the surface treating agent, water solution, in which 2-20% of deaeration-treated surface treating agent is dispersed, is gravitationally fed from a tank, in which said water solution is stored and which is installed above the continuously delivering glass fabric base material, on one side surface of the base material for uniform coating. Finally, the moisture in the water solution is removed with a dryer in order to obtain the prepreg concerned.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a prepreg base material for a laminate used in printed wiring boards and the like.

[Prior Art] Copper-clad laminates have been widely used as printed wiring boards. This laminate can be obtained by superimposing a required number of prepregs and copper foils and molding them under heat and pressure. At this time, the prepreg used is one in which a resin impregnated into a base material is semi-cured in the base material.

Since the inorganic glass cloth base material and the organic resin do not have good adhesion as they are, in order to improve the adhesion between the base material and the impregnated resin, a surface treatment agent is usually applied to the surface of the fibers that make up the base material. A coating process is applied. However, when this surface treatment agent is applied to a glass cloth substrate, the treatment agent foams due to the pores on the surface of the glass cloth substrate, resulting in unevenness on the surface of the substrate being treated. Since the resin varnish is not evenly impregnated in these uneven areas, the prepreg is unevenly impregnated with the resin, and when it is made into a laminate, it has problems with poor moisture absorption heat resistance and moisture absorption insulation properties.

[Problem to be solved by the invention]

An object of the present invention is to provide a prepreg base material for use in laminates, which can be satisfactorily impregnated with resin and has a uniform appearance.

[Means to solve the problem]

The present invention has been made in view of the above points, and its feature lies in a base material for prepreg coated with a defoamed surface treatment agent.

The present invention will be explained in detail below.

As the surface treatment agent according to the present invention, silane coupling agents such as aminorane, epoxysilane, and styrene silane can be used.

Base material N! l is not particularly limited, and preferably glass cloth or the like can be used. In addition, inorganic fiber cloths such as quartz fiber cloths and nonwoven fabrics thereof may also be used.

Methods for degassing include: ■ heating under reduced pressure in a state containing a porous material such as zeolite, or performing either heating or depressurization, ■ gas separation using a reverse osmosis membrane, and ■ vacuum degassing treatment. It can be selected and used as appropriate.

An example of a method for coating a substrate with a surface treatment agent is to use a glass cloth that is continuously fed through a tank containing an aqueous solution in which 2 to 20% of the surface treatment agent, which has been defoamed using the above method, is dispersed. An example of a method is to install the aqueous solution above the base material, supply an aqueous solution by gravity from a tank, apply it uniformly to one surface of the base material, and dry the water in a dryer.

Resins that can be used to impregnate this base material to make prepreg include phenolic resin, epoxy resin,
Resins consisting solely of thermosetting resins and thermoplastic resins such as unsaturated polyester resins, polyimide resins, polybutadiene resins, polyphenylene oxide resins, fluororesins, polyethylene terephthalate resins, and polyphenylene sulfide resins, modified products, and mixtures of these resins. There is a resin press in which non-III fillers such as glass powder, calcium carbonate, talc, and aluminum hydroxide are mixed into the resin.

Prepreg is produced by impregnating the resin press into a base material whose surface has been treated with a surface treatment agent that has been sufficiently defoamed, and then drying to evaporate the solvent and proceed with the reaction of the resin, semi-curing the resin in the base material. You can get it by doing this. The temperature during semi-curing is preferably 140 to 170°C. If the temperature exceeds 170°C, the reaction of the resin will proceed too much.
This will reduce the interlayer adhesion of the resulting prepreg and pose a risk of ignition from the evaporated solvent.

Next, the present invention will be explained with reference to Examples and Comparative Examples.

[Example] Example 1 Glass cloth of specification 1080 was surface-treated with a surface treatment agent consisting of a 2.0% aqueous solution of aminosilane at a treatment temperature of 40° C. and a degree of vacuum of 7×10' Pascal, and bromine was used as the epoxy resin. Chemical epoxy resin (Tobu Kasei, YD
100 parts by weight of B-50 (epoxy equivalent: 500), 2.1 parts by weight of dicyandiamide as a curing agent, 0.1 parts by weight of 2-ethyl 4-methyl imidazole as a curing accelerator, methyl ethyl ketone and dimethyl formamide as solvents. A resin varnish prepared by using an equal amount of the mixed liquid to have a resin content of 65% by weight based on the epoxy resin,
This resin press was impregnated into the glass cloth, and 150'
Each prepreg was obtained by drying for 10 minutes in a dryer of C.

This prepreg was cut into 1 m x 1 m squares, and the processed surface was visually inspected to determine the unevenness of the prepreg surface. If the unevenness is significant at 80% or more of the total, it is marked as ×, if it is less than 15%, it is marked as △, and the results are marked as △.
The appearance of the prepreg is shown below.

Stack 10 of these cut prepregs and place one layer on both surfaces.
A double-sided copper-clad laminate was obtained by placing a roughened copper foil having a thickness of 8 μm and using a steam press to perform lamination molding at a molding temperature of 170° C. and a molding pressure of 50 kg/cm” for 100 minutes.

Each test piece was cut out from the 1 m x 1 m square double-sided copper-clad laminate obtained in this way, and the insulation and heat resistance were tested by JI.
It was evaluated according to SC6481, and the results are shown in Table 1. Lead layer insulation resistance and soldering heat resistance (260°C 11 minutes)
It was shown as In terms of solder heat resistance, those with slight blistering were rated C1 as △, and those that were markedly blistered were rated as ×.

Example 2 The aminosilane in Example 1 was replaced with styrene silane,
Except for this, the same procedure as in Example 1 was carried out.

Example 3 The same procedure as in Example 1 was carried out except that the base material of specification 1080 in Example 1 was replaced with a glass cloth base material of specification fi 7628.

Example 4 The same procedure as in Example 1 was carried out, except that the aminosolane in Example 1 was replaced with styrene silane, and the base material of specification 1080 was replaced with a glass cloth base material of specification 7628.

Comparative Examples 1 to 4 Comparative Examples 1 to 4 were carried out in the same manner as in each Example except that the surface treatment agent of each Example was used as a surface treatment agent without defoaming, and the results shown in Table 1 were obtained.

From the results in Table 1, it can be seen that the prepregs of Examples have excellent appearance, as well as excellent electrical properties and heat resistance. The thinner base material with specification 1080 is better with specification 762.
It was also confirmed that the effect of the defoamed surface treatment agent was better than that of the glass cloth base material No. 8.

(Margin below) [Effects of the Invention] The base material for prepreg of the present invention makes it possible to obtain a good prepreg that has excellent resin impregnation properties and has a uniform appearance.

Patent applicant Matsushita Electric Works Co., Ltd.

Claims (2)

[Claims] (1) A prepreg base material coated with a defoamed surface treatment agent. (2) The base material for prepreg according to claim 1, wherein the base material is a glass cloth.