JPH0570757A - Adhesive composition - Google Patents

Abstract

PURPOSE:To provide an adhesive composition having good electrical insulating properties, heat resistance and processability and excellent storage stability. CONSTITUTION:The title composition is produced by mixing 100 pts. wt. epoxy resin with 1-50 pts.wt. epoxy-containing acrylonitrile/butadiene copolymer or epoxy-containing methacrylonitrile/butadiene copolymer (0.05-0.3 epoxy group is contained per 100g of the copolymer).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electric insulation, heat resistance,
And an adhesive composition having good processability and excellent storage stability.

[0002]

2. Description of the Related Art In recent years, the demand for electronic devices has been rapidly increasing, and the density and the number of layers of printed circuits have been further increased along with the miniaturization of light, thin, short, and small devices. Under these circumstances, the following problems have become apparent in the glass epoxy prepreg (prepreg made by impregnating glass fiber with epoxy resin) that has been widely used in the past as a substrate for printed circuit boards (wiring boards). I've been That is, since air in the glass epoxy prepreg must be removed when the substrate is manufactured, it is necessary to remove the air under high pressure (for example, 40 kg / c).
Since the molding is carried out by raising the temperature in two steps at m ² ), there is a problem that the resulting printed wiring board is left with thermal strain or pressure strain, resulting in a defective circuit pattern.

In order to solve this problem, it has been proposed to use a composition comprising an epoxy resin and acrylonitrile-butadiene rubber (NBR) instead of the glass epoxy prepreg. In this case, although low-pressure molding is possible, there is a problem in that the electrical characteristics (especially with time under high temperature and high humidity environment) are not sufficient because NBR is used. From this point, it was considered to use a carboxyl group-containing NBR instead of NBR in order to improve the electrical characteristics by increasing the compatibility with the epoxy resin and increasing the crosslink density. However, epoxy resin and carboxyl group-containing NB
The mixture with R has a problem in storage stability and is not practical because the reaction gradually proceeds at room temperature.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and has an epoxy group-containing material which is excellent in electric insulation, heat resistance and processability and is excellent in storage stability. It is an object to provide an adhesive composition having NBR. Here, the workability is the moldability when the substrate is manufactured, and the good means that the low pressure molding can be performed.

[0005]

The adhesive composition of the present invention comprises an epoxy resin (A) and an epoxy group-containing acrylonitrile-butadiene copolymer or an epoxy group-containing methacrylonitrile-butadiene copolymer (B) (epoxy). The group content is 0.05 to 0.3 per 100 g of the copolymer), and 1 to 50 parts by weight of (B) is added to 100 parts by weight of (A).

The structure of the present invention will be described in detail below. (1) Epoxy resin (A). The epoxy resin used in the present invention is, for example, a glycidyl ether type epoxy resin represented by a bisphenol A epichlorohydrin type epoxy resin, a cresol novolac type epoxy resin, an alicyclic epoxy resin, a liquid rubber-modified epoxy resin, and flame retardancy. It is an epoxy resin having two or more epoxy groups in one molecule such as the halogenated epoxy resin. As an electronic material, especially when the chlorine ion content is 10 ppm or less, the water-decomposable chlorine content is
It is preferably 0.1% or less.

(2) Acrylonitrile containing epoxy group
Butadiene copolymer or epoxy group-containing methacrylnitrile / butadiene copolymer (B), that is, epoxy group-containing (meth) acrylonitrile / butadiene copolymer
(B). The epoxy group-containing (meth) acrylonitrile / butadiene copolymer (B) is not particularly limited, but includes an epoxy group-containing monomer and is an epoxy group contained in the copolymer (B). The amount of EPHR (the number of epoxy groups contained in 100 g of the copolymer, hereinafter EPH
R) is 0.05 or more and 0.3 or less (0.05 to 0.3), preferably 0.1 to 0.2, and is an unsaturated nitrile represented by acrylonitrile or methacrylonitrile, and 1,3- It is a rubbery copolymer composed of a conjugated diene represented by butadiene. If the EPHR is less than 0.05, the crosslink density after curing will decrease, resulting in a decrease in electrical insulation.
If the EPHR exceeds 0.3, the storage stability will be reduced.

(3) The adhesive composition of the present invention comprises the above-mentioned epoxy resin (A) and an epoxy group-containing (meth) acrylonitrile-butadiene copolymer (B). The compounding amount of the epoxy group-containing (meth) acrylonitrile-butadiene copolymer (B) is 1 to 50 parts by weight (preferably 10 to 30 parts by weight) with respect to 100 parts by weight of the epoxy resin (A).
The range is. If it is less than 1 part by weight, the fluidity at the time of molding becomes excessive and the thickness retention of the adhesive composition layer deteriorates. On the other hand, if it exceeds 50 parts by weight, the viscosity of the adhesive composition at the time of molding becomes too high and the adhesion to the adherend becomes insufficient, resulting in poor adhesion. Further, in terms of electric characteristics, the characteristic level of the epoxy resin is lowered in terms of insulation.

(4) As the curing agent for the epoxy resin used in the present invention, those having latent curability are desirable from the viewpoint of storage stability. Specific examples include dicyandiamide and certain imidazole compounds (for example, 2-phenyl-
4-methyl-5-hydroxymethylimidazole, etc.)
Hardeners that are not compatible with epoxy resin at room temperature, Lewis acid salts represented by boron trifluoride amine complex, and hardeners adsorbed on porous materials such as molecular sieves and hardened with microcapsules. For example, the one in which the agent is wrapped. In particular, dicyandiamide, imidazole and the like are often used in glass epoxy prepregs, and all of them are effective curing agents. The blending amount of these curing agents may be selected each time depending on the balance between storage stability and properties of the cured product.

(5) In the adhesive composition of the present invention thus formed, calcium carbonate, clay, and
Inorganic filler typified by mica; Organic filler typified by silicon powder or fluorine powder; Vulcanizing agent of epoxy group-containing (meth) acrylonitrile-butadiene copolymer
(Sulfur-based, non-sulfur-based); flame retardants typified by antimony trioxide and aluminum hydroxide; surface treatment agents typified by silane coupling agents; coloring agents and the like may be added appropriately.

[0011]

【Example】

Examples 1 to 6 and Comparative Examples 1 to 6 Compositions having the formulation contents (parts by weight) shown in Table 1 and Table 2 were M
It was dissolved in EK (methyl ethyl ketone) to prepare a varnish having a solid content (%) shown in Tables 1 and 2. Then,
This varnish was coated on a release-treated polyethylene terephthalate (PET) resin film (release film) so that the film thickness after drying would be 100μ, and the resin film after drying was laminated with a roll laminator, and 2
An uncured film adhesive of 00μ was prepared.

Using this film adhesive, the storage stability, adhesive thickness uniformity, and copper foil peeling strength are as follows.
(kgf / cm ² ), solder heat resistance, and electrical insulation (Ω)
Was evaluated. Evaluation method of storage stability : The produced film adhesive was left under the condition of 20 ° C. and 65% RH, and the resin flowability with time was evaluated by the following.

A film sample of 50 ± 0.5 mm square is cut out and the sample weight (W ₁ ) is measured to the nearest 0.001 g. Next, this film sample is pressed at 120 ° C. (5 kg / cm ² ) by a hot plate press, pressed for 10 minutes, taken out, and cooled to room temperature. Then from the center of the test piece
Cut out a 35 ± 0.5 mm square and set the sample weight (W ₂ ) to 0.00
Measure up to 1g. Calculate the "resin flow" by the following formula.

Resin flow (%) = (W ₁ -2W ₂ ) / W ₁ × 100 This "resin flow" value (F) was measured at 22 ° C. and 65% RH immediately after the film adhesive was produced (F ₀ ). After leaving in the environment for 30 days (F
₁ ), F ₁ / F ₀ ≧ 0.5 was regarded as good resin flowability, and F ₁ / F ₀ <0.5 was regarded as poor. Correct, F ₀ ≧ 10
And Evaluation method of copper foil peeling strength : Glass epoxy board with one side BO treated copper foil (35μ) (1.6m
(Thickness) 120 film adhesive with a laminating roll
The lamination was performed at ℃ (roll temperature). Next, the roughened surface of a 35 μm copper foil was placed in contact with the film adhesive, and cured by pressing at 170 ° C. for 1 hour under the press conditions shown in Table 1. In addition, a cutter knife is used to make a cut in the copper foil with a width of 10 ± 0.1 mm, one end of the copper foil is peeled to an appropriate length, and the copper foil peeling strength is set by the method of JIS C6481, 5.7.3 (1). Was measured. Evaluation Method of Thickness Uniformity of Adhesive : With respect to the copper-clad laminate prepared above, 10 points were selected at arbitrary positions, and the cross-section was observed with a microscope to measure the thickness of the adhesive layer. At that time, the thickness variation is ± 5
Within μ, it was judged as good, and when it was out of ± 5 μ, it was judged as bad. Solder heat resistance evaluation method : Cut a test piece from the copper clad laminate prepared above into a square of 25 ± 1 mm and float it in a solder bath whose temperature is adjusted to 260 ° C so that the copper foil surface of the test piece is immersed in the solder. After immersing for 60 seconds, it was taken out, cooled to room temperature, and visually observed for blistering and peeling of the copper foil surface. Evaluation method for electrical insulation : A film adhesive was pasted on a comb-shaped pattern circuit board (line / space = 0.2mm / 0.2mm) prepared in advance with a laminating roll at 100 ° C (roll temperature). 7 kg / cm under reduced pressure (5 torr) in autoclave
Curing treatment was carried out at 170 ° C. for 1 hour while pressurizing at ² , and the insulation resistance between lines (DC500 V, resistance value after 1 minute application) was measured for the obtained sample. The higher the value, the higher the electrical insulation.

[0015]

[0016]

Note) * 1 Epicoat 1001 (produced by Yuka Shell Epoxy Co., Ltd.)
.. * 2 Epicoat 828 (produced by Yuka Shell Epoxy Co., Ltd.)
.. * 3 ESCN220F (manufactured by Sumitomo Chemical Co., Ltd.). * 4: 23% by weight of bound acrylonitrile, Mooney viscosity
(ML _{1 + 4} (100 ° C)) 50.

* 5 The amount of bound acrylonitrile is 23% by weight,
Mooney viscosity (ML _{1 + 4} (100 ° C)) 50. * 6 23% by weight of bound acrylonitrile, Mooney viscosity
(ML _{1 + 4} (100 ° C)) 50. * 7 23% by weight of bound acrylonitrile, Mooney viscosity
(ML _{1 + 4} (100 ° C)) 50. * 8 27% by weight of bound acrylonitrile, Mooney viscosity
(ML _{1 + 4} (100 ° C)) 48. * 9: 33% by weight of bound acrylonitrile, Mooney viscosity
(ML _{1 + 4} (100 ° C)) 50. * 10 Curesol 2P4MHZ (manufactured by Shikoku Chemicals Co., Ltd.)
..

[0019]

* 11 Park Mill D (manufactured by NOF CORPORATION). * 12 SANTINTONE No.5 (manufactured by ENGEL HARD). From Table 1 and Table 2, the adhesive composition of the present invention (Example 1
It can be seen that (6) to (6) are excellent in all of storage stability, adhesive thickness uniformity, copper foil peeling strength, solder heat resistance, and electrical insulation. Further, the adhesive composition of the present invention can be cured by heating it under a low pressure (7 kg / cm ^{2 in} Examples 1 and 4) in the form of a film, which is dissolved in a solvent to form a varnish at the time of use. Therefore, it can be seen that the moldability is good and therefore the workability is excellent.

On the other hand, Comparative Example 1 uses a carboxyl group-containing acrylonitrile-butadiene copolymer and thus has poor storage stability, and Comparative Example 2 similarly uses a carboxyl group-containing acrylonitrile-butadiene copolymer. However, since the EPHR is as low as 0.01, the storage stability is good, but the copper foil peeling strength and electrical characteristics are poor. In Comparative Example 3, the epoxy group-containing acrylonitrile
A butadiene copolymer is used, but its EPHR is 0.
Since it is 04, it is inferior in copper foil peeling strength, and Comparative Example 4
Similarly, an epoxy group-containing acrylonitrile-butadiene copolymer is used, but the EPHR is 0.40, so the storage stability is poor. In Comparative Example 5, the epoxy co-containing acrylonitrile-butadiene copolymer was used, but the amount used was 0.5 per 100 parts by weight of the epoxy resin.
Since the amount is too small, the copper foil peeling strength is poor and the adhesive thickness uniformity is poor. In Comparative Example 6, the epoxy resin-containing acrylonitrile-butadiene copolymer was used, but the amount used was 60 parts by weight per 100 parts by weight of the epoxy resin, which was inferior in solder heat resistance.

[0022]

As described above, the adhesive composition of the present invention has excellent storage stability and excellent electrical characteristics and processability, and is therefore suitable as an adhesive for electronic materials. Further, since it has excellent adhesive properties, it can be widely used as a film-liquid type structural adhesive for automobiles, aircrafts and the like.

Claims (1)

[Claims] 1. An epoxy resin (A) and an epoxy group-containing acrylonitrile / butadiene copolymer or an epoxy group-containing methacrylonitrile / butadiene copolymer (B) (epoxy group content is 0.05 to 0.3 per 100 g of the copolymer). Individual)
And 1 to 50 parts by weight of (B) per 100 parts by weight of (A).
An adhesive composition blended in a ratio of parts by weight.