JP2927001B2 - Adhesive composition for flexible printed wiring boards - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition suitable for bonding a plastic film used for a flexible printed wiring board to a reinforcing plate.

[0002]

2. Description of the Related Art Conventionally, an adhesive used for a substrate for a flexible printed wiring board or a reinforcing plate for a flexible printed wiring board requires a high temperature for curing as described in JP-A-62-59683. Needed long heating. Epoxy resin, acrylic resin, phenol resin, etc. are used for this kind of adhesive, and in order to obtain sufficient adhesive performance, aromatic polyamine, phenol, epoxy resin, etc. are used for the curing agent system. Since it is used, it was necessary to heat at a high temperature for a long time to cure. Moreover, these are not suitable for the adhesive between the component mounting reinforcing plate and the flexible printed wiring board because the flow of the adhesive is large.

[0003]

Means for Solving the Problems The present inventors have studied the above problems and found that the adhesive system has at least one epoxy group and one acrylamidomethyl group or methacrylamidomethyl group. Epoxy group, carboxyl group, hydroxyl group to glycidyl compound (B)
One or more functional group-containing acrylic elastomers (A) selected from the group of groups are combined, and an aromatic polyamine curing agent (C) suitable for them is combined with a specific range.
It has been found that, by also using the radical polymerization initiator (D) in an amount in combination, the curing speed can be increased, heat curing can be performed at a relatively low temperature for a short time, and the flow-out property can be extremely reduced. Reached.

That is, the present invention relates to a group consisting of an epoxy group, a carboxyl group and a hydroxyl group.
And a glycidyl compound having at least one epoxy group and at least one acrylamidomethyl or methacrylamidomethyl group per molecule (B). ,
The aromatic polyamine curing agent (C) and the radical polymerization initiator (D) are added to the solid content of the glycidyl compound (B).
Provided is an adhesive composition for a flexible printed wiring board, comprising 0.1 to 10 phr . Also has a feature in that exothermic decomposition temperature of La radical polymerization initiator is 25 to 120 ° C.. Also,

[0005] The glycidyl compound (B) is

It also has the feature of having the structure of

Embedded image (In the formula, R represents a hydrogen atom or a methyl group.) It is also characterized in that the compounding ratio of the acrylic elastomer (A) and the glycidyl compound (B) is in the range of 1/1 to 10/1 in terms of solid content weight ratio. It has.

Further, the present invention will be described in detail . Examples of the acrylic elastomer (A) used in the present invention, the one or major component more of A chestnut <br/> Le ester or α- substituted acrylic acid ester, at least one functional group as a crosslinking point to it It includes a polymer that is included, or a polymer obtained by (grafting) copolymerizing at least one of the functional group-containing monomers with the above-mentioned main component monomer.

That is , the acrylic elastomer (A) is
One or more of (a) an acrylate or an α-substituted acrylate is used as a large proportion of components, and (b) an epoxy group, (c) a carboxyl group, and (d)
An acrylic elastomer obtained by copolymerizing a monomer having one or more functional groups selected from the group of hydroxyl groups can be used.

Specific examples of the monomers (a) to (d) are shown below. Examples of the acrylate or α-substituted acrylate (a) include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, and the like.

Examples of the epoxy group-containing monomer (b) include glycidyl ethers such as vinyl glycidyl ether and allyl glycidyl ether; and glycidyl (meth) acrylates. Examples of the carboxyl group-containing monomer (c) include (meth) acrylic acid, itaconic acid, maleic acid, and maleic anhydride. Examples of the hydroxyl group-containing monomer (d) include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and the like . Further, if necessary, other vinyl monomers such as vinyl chloride, vinylidene chloride, styrene, methacrylonitrile, and vinyl acetate may be copolymerized.

The acrylic elastomer (A) includes:
Specifically, ARONTAC S-1511L, S-151
1X, S-1015, S-1017 (manufactured by Toa Gosei Chemical Co., Ltd.), Knoxtite PA-501, PA-502
(Manufactured by Nippon Mektron Co., Ltd.); Teisan Resin WS022,
WS023, SG51, SG80, SG90 (manufactured by Teikoku Chemical Co., Ltd.), AR-51 (manufactured by Zeon Corporation) and the like. These can be used alone or in combination of two or more.

The acrylic elastomer (A)
Is an epoxy group, a carboxyl group, may be those having a have <br/> functional groups either the hydroxyl groups, but among them those having a low temperature reaction of the epoxy group.

The glycidyl compound (B) used in the present invention is not particularly limited, but is generally one per molecule.
Any compound having one epoxy group and one acrylamidomethyl group or methacrylamidomethyl group may be used.

Curing agent (C) suitable for use in the present invention
Is, 4,4'-diaminodiphenylmethane, 4,4'
Diaminodiphenyl ether, an aromatic polyamine such as 4,4'-diaminodiphenyl sulfone.

Examples of the radical polymerization initiator (D) used in the present invention include organic peroxides such as lauroyl peroxide, benzoyl peroxide, cumyl peroxide and the like.

The mixing ratio of the acrylic elastomer (A) and the glycidyl compound (B) is such that the ratio of the acrylic elastomer (A) / glycidyl compound (B) is 1/1 to 10 /
The range of 1 is preferred, preferably the range of 2/1 to 6/1. When the blending ratio of the acrylic elastomer (A) is less than 1/1, the solder heat resistance decreases. Conversely, if it is more than 10/1, the adhesive strength will decrease.

Further, an aromatic polyamine curing agent (C) and a radical polymerization initiator (D) are added to the main components (A) and (B). The addition amount of ()) is desirably from epoxy equivalent to 1/2 epoxy equivalent. If the amount of the curing agent (C) added is less than 1/2 epoxy equivalent, a sufficient degree of curing cannot be obtained, resulting in a decrease in solder heat resistance. In addition, even if an epoxy equivalent or more is added, a gas containing S as a main component is generated in a solder heat resistance test, which is not desirable. The addition amount of the radical polymerization initiator (D) is 0.1 to 10 phr based on the solid content of the glycidyl compound (B).
Needs to be When the addition amount of the radical polymerization initiator (D) is 0.1 phr, it is difficult to shorten the curing time, and
If it is 0 phr or more, the adhesive strength and solder heat resistance are not sufficient.

Use of a solvent in the adhesive composition of the present invention
Can be. Examples of the solvent include methyl ethyl ketone, acetone, toluene, dioxane, methyl cellosolve acetate, ethylene glycol monomethyl ether, and the like, and mixtures thereof.

Various additives such as a plasticizer, an antioxidant, a fine inorganic filler such as anhydrous silica and aluminum hydroxide can be appropriately added to the adhesive composition of the present invention, if necessary. Needless to say.

To apply the adhesive composition of the present invention to a film or a reinforcing plate, the components of the adhesive composition are first mixed by a known mixing means, then dissolved in a solvent, and coated in a solution state. I do. In this case, after being applied to one of the adherends, lamination and curing are performed by an arbitrary heating and curing means.
For example, the coated material is dried in a hot air oven to dry the solvent, or is pre-cured to form a B-stage product, which is then combined with another object to be bonded, and then heated using a hot press.
A method of thermocompression bonding at 30 to 180 ° C. and a pressure of 5 to 40 kg / cm ² is employed. In addition, after the coating and drying are continuously performed, the coating may be continuously passed through a heating roll, and then heat-pressed and integrated to perform post-heating curing.

As the reinforcing plate to which the adhesive composition of the present invention is applied, aluminum plate, silicon steel plate, paper phenol laminate,
Glass epoxy laminates, polypropylene, polyethylene and the like can be mentioned. Further, the film to which the adhesive composition of the present invention is applied is not particularly limited as long as it is a polymer film, but particularly refers to a film used for FPC, such as a polyimide film, a polyester film, a polyether ketone film, and a polyether sulfone film. And ultra-thin laminates.

[0021]

The adhesive composition of the present invention can bond a plastic film used for a flexible printed wiring board to a reinforcing plate at a relatively low temperature in a short time, and has a pot life of 6 months or more. It has the advantage of extremely low flowability. Further, the adhesive composition of the present invention has adhesive strength, solder heat resistance, resistance to run-out, and a long pot life, which are properties required for adhesion between a plastic film used for a flexible printed wiring board and a reinforcing plate. Provide all satisfactory adhesives.

[0022]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but these do not limit the scope of the present invention. Example 1 Acrylic elastomer SG90 (trade name, manufactured by Teikoku Chemical Industry Co., Ltd .; containing an epoxy group as a functional group ) was dissolved in a mixed solvent of methyl ethyl ketone / toluene 1/1.
93.5 parts of a 0% by weight solution, Kaneka AXE (manufactured by Kaneka Chemical Co., Ltd., trade name;

(The glycidyl compound of the formula: R = H) 9.37
5 parts, 4,4'-diaminodiphenylmethane (manufactured by Sumitomo Chemical Co., Ltd., trade name) 1.8 as an aromatic polyamine
75 parts, and lauroyl peroxide (manufactured by Kayaku Akzo) 0.18 as a radical polymerization initiator
9 parts (0.189 / 9.375 × 100 = 2.02ph
r) was added to produce a viscous adhesive. Then, it is applied on a release paper so as to have a thickness of 40 μm in solid content.
The film was dried at 5 ° C. × 5 minutes to prepare a B-stage film.
Thereafter, the image was transferred to an A1 reinforcing plate, bonded to a flexible printed wiring board, and pressed under conditions of 170 ° C. × 5 minutes × 10 kg / cm ² . However, water cooling to room temperature is not performed after pressing.

(Example 2) SG80 (manufactured by Teikoku Chemical Industry Co., Ltd .; trade name; containing an epoxy group as a functional group ) was used as an acrylic elastomer.
The procedure was performed in the same manner as in Example 1 except that 4,4′-diaminodiphenyl ether was used as the aromatic polyamine. (Example 3) acrylic elastomer as WS023 (Teikoku Chemical Industry Co., Ltd., trade name; a carboxyl group and heat as the functional group
Containing a droxyl group ) as an aromatic polyamine,
The procedure was performed in the same manner as in Example 1 except that 4′-diaminodiphenyl sulfone was used.

(Comparative Example 1) The same procedure as in Example 1 was carried out except that no radical polymerization initiator was used. (Comparative Example 2) The amount of the radical polymerization initiator added was 1.407 parts (1.40 parts ).
7 / 9.375 × 100 = 15.01 phr) , except that the procedure was as in Example 1.

The method for evaluating the characteristics of the flexible printed wiring board (FPC) obtained according to the examples (comparative examples) is as follows. Adhesive strength: based on JIS C6481. Solder heat resistance: based on JIS C6481. Reflow resistance: Inlet temperature 300 ° C, outlet temperature 350
FP at a speed of 1m / min in a far-infrared heating furnace at ℃
Pass C. The result was visually observed. Flow-out resistance: A hole of 0.8 mm is made in the FPC, and the amount of bleeding of the adhesive after pressing is measured. Table 1 shows the results.

[0026]

[Table 1]

[0027]

As described above, the adhesive composition for a flexible printed wiring board of the present invention can be cured in a short time, and furthermore has an adhesive strength, solder heat resistance, reflow resistance, flow-out resistance and the like. It has excellent potability and a long pot life, and has a good balance of properties thereof. Therefore, it is particularly suitable for a reinforcing plate of a flexible printed wiring board.

Claims (4)

(57) [Claims] 1. An epoxy group, a carboxyl group, a hydroxy group,
Acrylic elastomer (A) having one or more functional groups selected from the group of sil groups and glycidyl having at least one epoxy group and one acrylamidomethyl or methacrylamidomethyl group in one molecule The compound (B), the aromatic polyamine curing agent (C) and the radical polymerization initiator (D) are combined with the solid content of the glycidyl compound (B).
0.1 to 10 phr with respect to the amount ,
An adhesive composition for a flexible printed wiring board. Wherein exothermic decomposition temperature of La radical polymerization initiator 2
The adhesive composition for a flexible printed wiring board according to claim 1, wherein the temperature is 5 to 120C. 3. The glycidyl compound (B) has the following structure:
The adhesive composition for a flexible printed wiring board according to claim 1. Embedded image (In the formula, R represents a hydrogen atom or a methyl group.) 4. The compounding ratio of the acrylic elastomer (A) to the glycidyl compound (B) is 1/1 to 10 in terms of solid content weight ratio.
The adhesive composition for a flexible printed wiring board according to claim 1, wherein the adhesive composition is in the range of / 1.