JPS63376A - Adhesive for additive process printed circuit board - Google Patents

Abstract

PURPOSE:To obtain the title having excellent resistance to the heat of solder and a soldering iron, by mixing an acrylonitrile-butadiene rubber, a thermosetting resin, and a specified comb-type graft copolymer. CONSTITUTION:A macromonomer obtained by polymerization or copolymerization of a (meth)acrylic ester is copolymerized with a hydrophilic monomer having any one of groups selected from among carboxyl, hydroxyl, acid amide, and polyoxyethylene groups to give a comb-type graft copolymer (D). 0.01-5wt% component D is dispersed in an adhesive which comprises an acrylonitrile-butadiene rubber (A), a thermosetting resin (B) such as a phenolic resin or an epoxy resin and, if necessary, an electroless plating catalyst, an inorganic filler, etc., (C).

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an adhesive used for manufacturing printed wiring boards by an additive method.

(Prior technology) Printed wiring boards using the additive method are made by drilling through-holes on an insulating substrate coated with adhesive (insulating substrate with adhesive) → forming electroless plating resist on areas other than those that will become circuits → chemically depositing the adhesive on the surface of the adhesive. Roughening → circuit formation by electroless plating,
Or through-hole drilling → chemical roughening of adhesive surface →
The manufacturing process is as follows: full-surface electroless plating → resist formation on areas other than the circuit area - electroplating → resist removal → quick etching to remove plating on areas other than the circuit area.

Adhesives used in additive printed wiring boards are susceptible to chemical roughening in order to firmly adhere conductor circuits, and as a result, adhesive strength is comparable to light, and high temperatures are required to mount electronic components. The basic requirement for solder confectionery is to have excellent heat resistance of more than 1 it. The surface of the adhesive layer needs to be chemically roughened prior to electrolytic plating, and the adhesive for this purpose is generally
Synthetic rubber that is susceptible to chemical roughening and flexible, such as acrylonitrile butadiene rubber, is the main component, and is crosslinked with alkylphenol town fat to maintain heat resistance.
Furthermore, adhesives made by directly blending epoxy resins and the like have been proposed. (For example, Special Publication No. 48-24250, Special Publication No. 45-9843, Special Publication No. 45-9996, Special Publication No. 55
-16391, Special Publication No. 52-31539).

(Problems to be Solved by the Invention) However, in recent years, it has become necessary to further improve the heat resistance of adhesives for additive printed wiring boards that are applied to electronic devices that have become increasingly sophisticated.

For example, a solder bath with a temperature of 260° C. or higher should be used for ease of soldering the mounted components and connection reliability. Furthermore, installed electronic components may have to be replaced due to circuit defects, and in such cases, manual soldering work using a soldering iron at high temperatures of over 300°C, and sometimes as high as 400 to 420°C, is required. It will be done.

At such high temperatures, blistering may occur at the interface between the substrate and the adhesive, which is a fatal defect for wiring boards. Such bulging during soldering is not only due to the lack of heat resistance of the adhesive itself, but also because the adhesive interface between the adhesive and the base material is destroyed by the gas generated by the base material.

The present invention provides an adhesive for use in adhesive-attached insulating substrates for additive printed wiring boards, etc., which has excellent solder heat resistance and soldering iron heat resistance.

(Means for Solving the Problems) The present invention has an acrylonitrile butadiene rubber and a thermosetting resin as essential components, and a macromonomer for homopolymerization or copolymerization of an acrylic ester or a methacrylic ester. It is made by adding a comb-shaped graft copolymer copolymerized with a hydrophilic monomer having either a carboxyl group, a hydroxyl group, an acid amide group, or a polyoxyethylene group.

The comb-shaped graft polymer is described in "Kagaku to Kogyo" Vol. 38, No. 6 (1985), pp. 432-434, Japanese Patent Publication No. 60-15.
659, JP 58-154766, JP 58-164656, JP 58-16760
Publication No. 6, JP-A-59-20360, JP-A-59
As shown in Publication No. 7B256, it is a surface modifier that has excellent interfacial migration properties, has the effect of improving the adhesive force at the adhesive-substrate interface, and suppresses blistering at high temperatures. It is something. The addition amount of these modifiers should be α01 to 5% by weight to give good results. Q: If it is less than 0.1% by weight, it will not be effective, but if it exceeds 5% by weight, it will not be possible to obtain the desired effect and other properties may be deteriorated. These are used as modifiers for plastics by Toagosei Kagaku Kogyo ■, including Aron GC-10 as a carboxyl group type and Aron GH-20 as a hydroxyl group type.
etc. are commercially available.

As an adhesive, acrylonitrile butadiene rubber is an essential component, and thermosetting resins such as phenol resin and epoxy resin are also used.

In addition, it is possible to add a catalyst for electroless plating or to mix an inorganic filler with the required VC.

When depositing electroless plating, the surface of the adhesive is chemically roughened to give it a shape suitable for adhesion, and the catalyst for electroless plating is exposed on the surface.

As the filtration liquid used for chemical roughening, general chromic acid-sulfuric acid, Natsuri Romu-Toshi-TtL acid, etc. can be used.

As the electroless plating bath, one that can form a plating film on general steel is used.

Example 1 Acrylonitrile butadiene rubber (N-1432J, manufactured by Nippon Zeon ■) Phenolic resin (5p126, manufactured by Schenectady) 35 parts epoxy resin (oiled shell split Epicoat E-1001)
) 10 parts Zirconium silicate (Cyclopax 2OA, manufactured by Hakusui Chemical) 30 parts Plating solvent (PEC-8, manufactured by Hitachi Chemical Juko) 8 parts Surface modifier (Toagosei Chemical Co., Ltd. Moxibustion Aron GC-10) (Graft polymer 25% solution)
An adhesive solution having a solid content of 22% was prepared by dissolving 164 parts of 1 in a mixed solvent of cellosolve acetate and methyl ether ketone in a 1:1N ratio using a Nigu. Apply this adhesive to a zoomm square paper phenol laminate (Hitachi Chemical, product name LP-14).
1) and paper epoxy laminate (LE-144), dip coated on both sides so that the adhesive film thickness after drying was 25 μm, and heated and dried at 760°C for 60 minutes to obtain an adhesive-coated extreme R board. I got it.

Next, a mixture of chromic acid (355 g of Cry, 210 g of concentrated sulfuric acid
1! +1 diluted with water to make a total of 12) at 40°C.
It was immersed for 5 minutes to perform chemical roughening treatment and washed with water. Next Ki
! Deplating was carried out at 67°C for 30 hours.

The thickness of the copper obtained is 35μ. 6 at 160℃ after washing with water
It was heated and dried for 0 minutes.

The heat resistance test results are shown in Table 1.

Example 2 Acrylonitrile butadiene rubber (N-1001 manufactured by Nippon Zeon ■) 70 parts 2 eno/L
-Resin (Schenectady 5P126)
30 parts phenol resin (Schenectady Table 5P6600) 1 part epoxy resin (DEN438 manufactured by Dow Chemical Company) 10 parts zirconium silicate (Micropax 20A manufactured by Hakusui Kagaku ■)
3 (3 parts plating catalyst (PEC-8 made by Hitachi Chemical Co., Ltd.) 8 parts surface modifier (Toagosei Chemical Industry Solid Aron GH-20) 6.4 parts to prepare an adhesive in the same manner as in Example 1 The mixture was coated on a substrate and dried to obtain an insulating substrate with an adhesive.

Table 1 shows the heat resistance test results after this product-1 electroless plating.

Comparative Example 1 An adhesive was prepared from the composition of Example 1 with the surface modifier removed, and a printed wiring board was prepared in the same manner as in Example 1. This characteristic is shown in Table 1.

Comparative Example 2 An adhesive was prepared from the composition of Example 2 except for the surface modifier, and a printed wiring board was prepared in the same manner as in Example 2. The characteristics are shown in Table 1.

Table 1 Measurement method Based on JIS, C-'54s1. 1 seconds to failure in a 260°C solder bath.

2) After soldering the electronic components mounted in the through hole using a flon luder adjusted to 260℃,
Remove the solder and replace the electronic components using a solder sucker adjusted to 0°C, then repeat solder connections using a soldering iron adjusted to 420°C and parts replacement using a solder absorber to remove the land in the through-hole area. Measure the number of times until connection loss occurs due to breakage, blistering, etc.

(Effects of the Invention) The adhesive of the present invention improves the heat resistance of, for example, additive printed wiring boards, particularly the soldering heat resistance and soldering iron heat resistance.
It is something that

Claims (1)

[Claims] 1. Acrylonitrile butadiene rubber, thermosetting resin as an essential component, and a macromonomer obtained by homopolymerization or copolymerization of acrylic acid ester or methacrylic acid ester and either carboxyl group, hydroxyl group, acid amide group, or polyoxyethylene group. 0.01 to 5% by weight of a comb-shaped graft copolymer copolymerized with a hydrophilic monomer having
Additive method adhesive for wiring boards made by adding and dispersing.