JPH10130400A - Production of adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive film improve in heat resistance while retaining its adhesivity and capable of sustaining its adhesivity even when it is subjected to long-term exposure at high temperatures, by using an adhesive composition containing an inexpensive specific modified polyamide-epoxy resin. SOLUTION: First, a modified polyamide-epoxy resin 1,000-400,000 in epoxy equivalent is prepared by reaction, in the molar ratio: epoxy group/carboxyl group of >1, or an epoxy resin with a carboxyl-terminated polyamide resin produced by reaction between (A) a polycarboxylic acid component composed of 10-70 pts.wt. of a carboxylic acid with both ends terminated with polyalkylene glycol or polycarbonate diol and 90-30 pts.wt. of another aliphatic or aromatic polycarboxylic acid and (B) a diisocyanate in the molar ratio: carboxyl group/ isocyanate group of >1. Next, a base material is coated with a resin composition prepared by incorporating the above modified polymide-epoxy resin with a flame retardant and an oligomer formed by reaction between bismaleimide and a diamine, followed by drying, thus obtaining the objective adhesive film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an adhesive film used as an interlayer adhesive for a multilayer FPC, a rigid flex wiring board (FRC) or an adhesive between an FPC and a reinforcing plate.

[0002]

2. Description of the Related Art Due to the trend toward thinner and smaller electronic devices,
The FPC field, which is flexible and easy to thin, is expanding its market every year. In particular, in recent years, high-density has been required, and thus, multi-layering has been advanced. Furthermore, with the miniaturization of equipment, rigid-flex wiring boards in which a rigid wiring board and a flexible wiring board are combined have begun to be used in the field of OA equipment including mobile phones. Further, a reinforcing plate is used to fix the terminals of the flexible wiring board. As an adhesive film used for these wiring boards, an acrylic adhesive is generally used. However, since the acrylic resin has a low Tg (glass transition temperature), there is a disadvantage that the wiring board is wavy at the time of soldering. In addition, when used as an interlayer adhesive for a multilayer FPC or FRC, there is a disadvantage that smear is easily generated.

[0003]

Therefore, in recent years, polyimide-based adhesive films have come to be marketed in order to solve these disadvantages. However, polyimide-based adhesive films are expensive and have drawbacks such as being unable to be bonded with a roll laminator, and are not yet widely used. In addition, as an inexpensive adhesive film having a high Tg, Japanese Patent Application Laid-Open
As proposed in No. 7, inexpensive polycarboxylic acids,
There is an amide group-containing epoxy resin composed of diisocyanate and epoxy resin. Furthermore, it is known that high adhesiveness can be obtained by introducing a flexible component such as a polyalkylene chain or a polycarbonate chain into the resin as proposed in Japanese Patent Application No. 7-101800. However, as a result of introducing these soft components (soft segments), thermal deterioration is apt to occur, and there is a problem in maintaining long-term adhesiveness.

[0004]

The present invention solves these problems, and comprises a polycarboxylic acid, a diisocyanate, and an epoxy resin, and a polyalkylene chain or a polycarbonate chain is introduced into a polyamide skeleton. A resin composition obtained by adding a flame-retardant, a maleimide oligomer obtained by reacting a bismaleimide and a diamine, to an inexpensive modified polyamide epoxy resin into which these flexible components (soft segments) are introduced, whereby high adhesiveness is obtained. It is. It is an object of the present invention to provide an adhesive film produced from an adhesive composition having improved heat resistance while maintaining adhesiveness, and having an effect of maintaining adhesiveness for a long-term high-temperature exposure. .

In order to achieve the above object, the method for producing a bonding sheet according to the present invention comprises: (A) a polycarboxylic acid component having a carboxylic acid at both terminals of a polyalkylene glycol or a carboxylic acid at both terminals of a polycarbonate diol; 70 parts by weight, 90 to 30 parts by weight of another aliphatic or aromatic polycarboxylic acid, (B) a carboxylic acid-terminated polyamide resin obtained by reacting diisocyanate under the condition of -COOH / -NCO> 1, and an epoxy resin A resin composition obtained by adding a flame retardant, an oligomer obtained by reacting a bismaleimide and a diamine to a modified polyamide epoxy resin having an epoxy equivalent of 1,000 to 40,000, obtained by reacting a resin under the condition of epoxy group / carboxylic acid group> 1 And dried and manufactured.

The polyamide resin of the present invention can be synthesized by a condensation reaction in which carbon dioxide is eliminated from a polycarboxylic acid and a diisocyanate.

The polyalkylene glycol used as the component (A) in the present invention includes polytetramethylene glycol, polypropylene glycol,
Examples include polyvalent carboxylic acids obtained by reacting polyethylene glycol and the like with the carboxylic acids listed below. The carboxylic acid at both ends of the polycarbonate diol is a polyvalent carboxylic acid obtained by reacting a linear aliphatic polycarbonate diol with a carboxylic acid described below. Specific examples of the linear aliphatic polycarbonate include Plaxel CD series (trade name, manufactured by Daicel Chemical Industries, Ltd.) and Nipporan 980 and 981 (trade names, manufactured by Nippon Polyurethane Industry Co., Ltd.). These are used in an amount of at least 10% by weight in the polyamide resin from the viewpoint of adhesiveness and at most 70% by weight from the viewpoint of heat resistance. Furthermore, polytetramethylene glycol is preferable from the viewpoint of adhesion and moisture absorption resistance, and the molecular weight is preferably 200 to 3000.

[0008] Other aliphatic or aromatic polycarboxylic acids used in the present invention include succinic acid, glutaric acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, decandioic acid, dodecandioic acid and dimer acid. Such as aliphatic dicarboxylic acids, isophthalic acid, terephthalic acid, phthalic acid, naphthalenedicarboxylic acid, aromatic dicarboxylic acids such as oxidine benzoic acid, trimellitic anhydride, pyromellitic anhydride, diphenylsulfonetetracarboxylic dianhydride, etc. And aromatic carboxylic anhydrides. These are used alone or in combination of two or more kinds in an amount of 90 to 30 parts by weight.

The diisocyanate (B) used in the present invention includes 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 1,5-naphthalenediisocyanate, 3,3'-dimethyl-4,4'-
Diphenylmethane diisocyanate, p-phenylene diisocyanate, m-xylene diisocyanate, m-
Aromatic diisocyanate such as tetramethyl xylene diisocyanate, hexamethylene diisocyanate, 2,
2,4-trimethylhexamethylene diisocyanate,
Examples include aliphatic diisocyanates such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, transcyclohexane-1,4-diisocyanate, hydrogenated m-xylene diisocyanate, and lysine diisocyanate. Among these, aromatic diisocyanates are preferred from the viewpoint of heat resistance.
4'-diphenylmethane diisocyanate and tolylene diisocyanate are particularly preferred. These may be used alone, but it is preferable to use two or more kinds in combination because the crystallinity is increased. The component (B) is used such that the carboxylic acid group (—COOH) / isocyanate group (—NCO)> 1 with respect to the component (A), the carboxylic acid is excessive, and the terminal of the polymer is a carboxyl group.

In the above reaction, lactones such as γ-butyrolactone, amide solvents such as N-methylpyrrolidone (NMP), dimethylacetamide and dimethylformamide (DMF), tetramethylene sulfone (sulfolane),
The reaction is carried out at 50 ° C. to 250 ° C. using sulfones such as dimethyl sulfoxide (DMSO) and ethers such as diethylene glycol dimethyl ether as a solvent. Considering the reaction yield, solubility and volatility in the subsequent step, it is preferable to use γ-butyrolactone as the main component of the solvent.

The epoxy resin used in the present invention includes aromatic epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, naphthalene type epoxy resin, and neopentyl. Examples thereof include aliphatic epoxy resins such as glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and diglycidyl tetrahydrophthalate, and heterocyclic epoxy resins such as triglycidyl isocyanurate. Of these, bifunctional epoxy resins are preferred from the viewpoint of reaction control, and aromatic epoxy resins are preferred from the viewpoint of heat resistance. A brominated epoxy resin is useful for imparting flame retardancy. These are used alone or in combination of two or more. These epoxy resins are reacted with a carboxylic acid-terminated polyamide resin under the condition of epoxy group / carboxylic group> 1.
If the epoxy group / carboxylic acid group is smaller than 1, a resin having a terminal epoxy group cannot be obtained. In addition, epoxy group /
If the carboxylic acid group is> 2, the epoxy resin may react excessively to form a three-dimensional gel. The modified polyamide epoxy resin thus obtained preferably has an epoxy equivalent of 1,000 to 40,000. 1
If it is less than 000, the molecular weight is low and the film formability is poor, and if it exceeds 40,000, the viscosity of the varnish becomes high, making film production difficult.

The maleimide oligomer which is an oligomer obtained by reacting bismaleimide and diamine used in the present invention includes 4,4'-diaminodiphenylmethane,
4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, m-phenylenediamine, p-
Maleimides obtained by reacting aromatic diamines such as phenylenediamine and 2,2-bis- [4-aminophenoxyphenyl] propane with these diamines and maleic anhydride can be prepared by converting the molar ratio of diamine / maleimide from 0.2. The reactive oligomer obtained by reacting at 0.5 is added.

The resin composition used in the present invention can be generally applied to an adhesive or an adhesive film in combination with an epoxy resin or an epoxy resin curing agent.

The epoxy resin is not particularly limited as long as it can be mixed with the modified polyamide epoxy resin. One or more of the above-mentioned epoxy resins can be used in combination regardless of the number of functional groups. The mixing ratio is preferably from 5 to 150 parts by weight of the epoxy resin based on 100 parts by weight of the modified polyamide epoxy resin.

The epoxy resin curing agent used in the present invention is not particularly restricted but includes, for example, aliphatic polyamines, secondary or tertiary amines, organic acids, imidazoles, dicyandiamide, polymercaptan, phenolic resins and the like. Is mentioned. These are used in an appropriate amount depending on the type of the curing agent from the viewpoint of adhesiveness, heat resistance and other properties.

In the present invention, conventionally known curing accelerators, coupling agents, fillers, pigments, and the like may be appropriately compounded, if necessary, in addition to the above components.

The resin of the present invention comprising the above components is dissolved in a solvent and used as an adhesive. Also, this resin solution is
Metal foil, polyester film with a peeled surface,
An adhesive film can be obtained by coating a substrate such as a polyimide film or paper by a conventionally known method, followed by drying and peeling from the substrate.

As the solvent, the solvent used in the production of the modified polyamide epoxy resin may be used as it is.
In addition, various solvents such as tetrahydrofuran, dioxane, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, ethyl acetate, butyl cellosolve, and chlorophenol can be used.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described specifically.

[Polytetramethylene glycol (PT
Production Example of G) Terminal Carboxylic Acid Compound (A-1)] PTG (average molecular weight: 1000) 100 in a flask equipped with a stirrer, a reflux condenser, an inert gas inlet and a thermometer.
0 g and 405 g of sebacic acid.
The temperature was raised to 00 ° C., and after further reacting for 3 hours, the mixture was cooled to obtain a carboxylic acid at both ends of PTG having an acid value of 81.9 and a molecular weight of 1370.

In the same manner, the following compounds A-2 to A-4, which are carboxylic acid compounds at both ends of polyalkylene glycol or polycarbonate diol, having the composition shown in Table 1 are used.
I got Polytetramethylene glycol (PTG average molecular weight 2
000) carboxylic acid compound at both ends (A-2)

Carboxylic acid compound at both ends of polypropylene glycol (PPG average molecular weight 950) (A-3)

Polycarbonate diol (Placcel C
D210, a product of Daicel Chemical Industries, Ltd., trade name, average molecular weight: 1000) Carboxylic acid compound at both terminals (A-4)

[0024]

[Table 1]

[Modified polyamide epoxy resin (B-1)
Production Example] In a flask equipped with a stirrer, a reflux condenser, an inert gas inlet and a thermometer, γ-butyrolactone 10 was added.
0 g and NMP 50 g, and then the above (A-1)
37.9 g, 7.9 g of adipic acid as another aliphatic or aromatic carboxylic acid, 10.9 g of sebacic acid, 18.0 g of isophthalic acid, 4,4 as a diisocyanate
4'-diphenylmethane diisocyanate (MDI)
25.5 g, Coronate T80 (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd .; tolylene diisocyanate TDI)
17.7 g was charged, the temperature was raised to 200 ° C., and the mixture was reacted for 4 hours and then cooled. Heating residue (resin content) 40% by weight,
A polyamide resin having an acid value of 54.8 was obtained. Further, 22.4 g of an epoxy resin EPOMIK R140 (trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd.) was charged and reacted at 150 ° C. for 3 hours. Dimethylformamide (DMF) was added to make a heating residue of 35% by weight, and an epoxy equivalent ( (Solid content conversion)
9300 modified polyamide epoxy resin was obtained.

As shown in Table 2, modified polyamide epoxy resins (B-2) to (B-
4) was obtained.

[0027]

[Table 2]

[Production Example of Maleimide Oligomer (C-1)] In a flask equipped with a stirrer, a reflux condenser and an inert gas inlet, 2,2-bis [4- (4-aminophenoxy) phenyl] propane was placed. 570.4 g of bismaleimidated product of (BAPP), 123.2 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane, DM
463 g of F was charged and reacted at 125 ° C. for 0.5 hour. After the reaction, the mixture was cooled to obtain a varnish having a resin content of 60% by weight.

As shown in Table 3, the maleimide oligomers (C-2) to (C-2) were prepared in the same manner as in the production example of (C-1).
-4) was synthesized.

[0030]

[Table 3]

(Example 1) 70 parts by weight of modified polyamide epoxy resin (B-1) 25 parts by weight of BREN105 (trade name, manufactured by Nippon Kayaku Co., Ltd.) 5 parts by weight of bismaleimide oligomer (C-1) 0.5 parts by weight of 2-ethyl-4-methylimidazole 100.5 parts by weight in total

The adhesive having the above composition was applied on a polyethylene terephthalate (PET) film, and was continuously conveyed at a rate of 0.1 m / min to a drying oven (length 1 m) at 120 ° C. To prepare a B-stage adhesive film. This adhesive film is coated with electrolytic copper foil (35μ).
m) sandwiched between a glossy surface and a polyimide film (Kapton), laminated at 170 ° C. for 30 minutes under a pressure of 4 MPa,
A polyimide film with copper foil (hereinafter abbreviated as MCF) was manufactured. Similarly, electrolytic copper foil (35 μm)
m) sandwiched between the roughened surface and the polyimide film (Kapton), and laminated at 170 ° C. for 30 minutes under a pressure of 4 MPa.
A polyimide film with a copper foil was manufactured. The adhesiveness of each interface of the MCF and the time until blistering occurred when floating in a 260 ° C. solder bath were measured. Table 4 shows the results.

(Embodiment 2) Instead of (B-1), (B-
2), MCF was prepared in the same manner as in Example 1 except that (C-2) was used instead of (C-1), and the characteristics were evaluated.

(Embodiment 3) Instead of (B-1), (B-
MCF was prepared under the same conditions as in Example 1 except that (C-3) was used instead of (3) and (C-1), and the characteristics were evaluated.

(Embodiment 4) Instead of (B-1), (B-
4), MCF was prepared under the same conditions as in Example 1 except that (C-4) was used instead of (C-1), and the characteristics were evaluated.

Table 4 shows the evaluation results of Examples 2 to 4.

Comparative Example 1 An MCF was prepared using only the modified polyamide epoxy resin (B-1), and the characteristics were evaluated.

Comparative Example 2 An MCF was prepared using only the modified polyamide epoxy resin (B-2), and its characteristics were evaluated. Table 4 shows the evaluation results of Comparative Examples 1 and 2. Table 4 shows that
Under the following conditions, chemical resistance and adhesive strength after heat treatment were measured and shown.

Chemical resistance: The adhesive films prepared above were immersed in 10% by weight of NaOH and 10% by weight of HCI aqueous solution for 24 hours, and the appearance was observed. Dissolution, discoloration,
Those having no cracks and the like were evaluated as good. Others were considered bad.

Adhesion strength after heat treatment: The obtained MCF was put in a high-temperature bath at 125 ° C., and the adhesion strength after 500 hours was evaluated. The produced adhesive film has no significant difference in chemical resistance, solder heat resistance and adhesive strength between the modified polyamide epoxy resins of Comparative Examples 1 and 2 and Examples 1 to 4 of the present invention under normal conditions. In the adhesive strength after the heat treatment for 500 hours, the adhesive strength was maintained in Examples 1 to 4, whereas the adhesive strength was significantly reduced in Comparative Examples 1 and 2. As described above, the present invention is excellent in maintaining long-term adhesiveness.

[0041]

[Table 4]

[0042]

As described above, according to the present invention, the adhesiveness between copper and a resin such as a polyimide film, which are indispensable for electronic materials and semiconductor materials, and the heat resistance of solder are excellent.
It is possible to provide an adhesive film showing stable adhesiveness against thermal deterioration due to long-term heating.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takao Hirayama, Oyama Gobanichi, Kajima-gun, Kashima-gun, Ibaraki Prefecture Inside Kashima Plant, Hitachi Chemical Co., Ltd. Banichi Hitachi Chemical Co., Ltd. Kashima Plant

Claims (1)

[Claims] 1. A polycarboxylic acid component having 10 to 70 parts by weight of a carboxylic acid at both terminals of a polyalkylene glycol or a carboxylic acid at both terminals of a polycarbonate diol, and 90 to 90 parts by weight of another aliphatic or aromatic polycarboxylic acid. 30
Parts by weight, (B) diisocyanate is -COOH / -NC
O> epoxy equivalent obtained by reacting an epoxy resin with a carboxylic acid-terminated polyamide resin obtained under the condition of O> 1 under the condition of epoxy group / carboxylic acid group> 1.
A method for producing an adhesive film, comprising applying a resin composition obtained by adding a flame retardant, an oligomer obtained by reacting a bismaleimide and a diamine to a modified polyamide epoxy resin having a molecular weight of 0 to 40,000, onto a substrate, and drying.