JPH03290489A - Imide adhesive - Google Patents

Abstract

PURPOSE:To provide an imide adhesive having improved heat resistance without deteriorating characteristics such as adhesivity and flexibility by compounding a specific aminobismaleimide with a specific acrylic resin in a specific ratio. CONSTITUTION:The objective adhesive agent comprises (A) 100 pts.wt. of an aminobismaleimide prepared by reacting bismaleimide with a diamine in a mol ratio of 1:0.5-1.5 at a high temperature in an ethereal polar solvent and (B) 10-1000 pts.wt. of an acrylic resin prepared by copolymerizing (i) 15-35wt.% of acrylonitrile, (ii) 55-83wt.% of the ester of a <=5C alcohol with (meth)acrylic acid and (iii) 2-10wt.% of (meth)acrylic acid.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a bismaleimide resin pressure-sensitive adhesive.

More specifically, the present invention relates to a bismaleimide adhesive used as a highly heat-resistant adhesive for tape.

(Prior Art) In recent years, with the diversification of demand, adhesive tapes with excellent heat resistance have been attracting attention.

Conventional heat-resistant adhesive tapes are made by applying adhesives such as NBR/phenol resin, phenol resin/butyral resin, NBR/epoxy resin, acrylic resin, etc. to metal foil such as aluminum or highly heat-resistant plastic film such as polyimide. However, these adhesives have problems with heat resistance such as long-term thermal deterioration and adhesive strength when heated, and even if heat-resistant polyimide is used as a film, it is difficult to fully utilize its performance. I couldn't do it.

(Problems to be Solved by the Invention) As a result of intensive studies to overcome the above-mentioned drawbacks, the present invention uses a bismaleimide/diamine/acrylic resin adhesive to improve adhesiveness, flexibility, etc. The present invention was completed based on the knowledge that heat resistance can be improved without impairing other properties required of the tape.

(Means for Solving the Problems) An excellent adhesive tape can be obtained by using an adhesive composed of the following (a) and (b) on a plastic film such as polyimide and a metal foil.

(a) molar ratio of 1 to 0.5 to 1.
100 parts by weight of aminobismaleimide obtained by heat-reacting diamine No. 5 in an organic polar solvent (b) 15 to 35% by weight of acrylonitrile, ester of alcohol having 5 or less carbon atoms and acrylic acid and/or methacrylic acid 55 ~
10 to 1000 parts by weight of an acrylic resin obtained by copolymerizing 83% by weight and 2 to 10% by weight of acrylic acid and/or methacrylic acid (function) In order to obtain good results in the present invention, the pressure-sensitive adhesive component must be It is essential to blend the ingredients in the compositions and proportions shown in (a) and (b).

That is, the present invention provides a combination of (a) bismaleimide represented by general formula (I) (in which R represents a divalent group containing at least two carbon atoms) and general formula () % formula % () ( In the formula, R represents a divalent group containing at least two carbon atoms. The imide pressure-sensitive adhesive is characterized in that 10 to 1000 parts by weight of the acrylic resin specified in (b) is added to 100 parts by weight of aminobismaleimide obtained by heat reaction in a solvent.

In the present invention, examples of the bismaleimide represented by the general formula (1) include N,N'-m-phenylenebismaleimide, N,N'-(γ,γ゛-(dipropyl)spiroacetal)bismaleimide, N , N'-p-phenylenebismaleimide, N,N'-oxy(di-p-phenylene)bismaleimide, N,N'-methylene(di-
p-phenylene) bismaleimide, N,N'-sulfo(
di-p-phenylene) bismaleimide, N, N'-m-
Phenylenebis(p-oxyphenylene)bismaleimide, N,N'Hexamethylenebismaleimide, N,N'
-decamethylene bismaleimide, N,N'-oxydipropylene bismaleimide, ethylenedioxybis(n-
propylmaleimide), N,N'-methylene (di1.
4-cyclohexylene) bismaleimide, N,N'-isopropylidene (di-1,4-cyclohexylene) bismaleimide, 2.6-xylylene bismaleimide, 2.
5-Oxadiazolylene bismaleimide, N, N'-p
-Phenylene (dimethylene) bismaleimide, N, N'
-Thio(diphenylene)dicitraconimide, N, N'
-methylene(di-p-phenylene)bis(chlormaleimide), N,N'-hexamethylenebis(cyanomethylmaleimide), etc., and these may be used alone or in a mixture of two or more types. I can do it.

Further, the diamine represented by the general formula (11) is, for example, 4
．． 4°-diaminodiphenylsulfone, 3.3′-diaminodiphenylsulfone, 4.4°-diaminodiphenylmethane, 4.4°-diaminodiphenyl ether, m
-phenylenediamine, p-phenylenediamine.

2.2°-bis(4-aminophenyl)propane, benzidine, 2.2-bis(4-(4-aminophenoxy)
phenyl)propane, 4.4°-diaminodiphenyl sulfide, bis(4-aminophenyl)methylphosphinoxide, bis(4-aminophenyl)phenylphosphinoxide, bis(4-aminophenyl)methylamine, 1.5 -diaminonaphthalene, 1,1-bis(p
-aminophenyl)phthalane, 4.4°-diaminobenzophenone, 4.4”-diaminoazobenzene, bis(4-aminophenyl)phenylmethane, 1.3-bis(3-aminophenoxy)benzene, 1.1-bis (
Examples include 4-amino-3-methylphenyl)cyclohexane, which can be used alone or in combination of two or more.

The above-mentioned bismaleimide and diamine are heated and reacted in an organic polar solvent, and such solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monopropyl ether,
Ethylene glycol monoethyl ether acetate, N
-Methyl 2-pyrrolidone etc. can be used, but
These solvents can be used alone or as a mixed solvent of two or more. Other acetone,
Methyl ethyl ketone, etc. may be used in combination.

The molar ratio of diamine to bismaleimide is 1:0.5
The range is preferably from 1.5 to 1.5, more preferably from 0.98 to
A range of 1.05 is desirable. The molar ratio of diamine is 05
If it is less than 1.5 mol, bismaleimide tends to precipitate in the aminobismaleimide solution, and if it exceeds 1.5 mol, it will have an unfavorable effect on the heat resistance of the adhesive after curing.

Above, the reaction temperature of bismaleimide and diamine is
The temperature range is preferably from 80 to 120°C; below 80°C, the reaction does not proceed sufficiently, and above 120°C, side reactions occur and are difficult to control. The reaction time is preferably in the range of 20 to 300 minutes; if it is less than 20 minutes, the reaction will not proceed sufficiently, and if it is more than 300 minutes, it will take too much time, which is not preferred in practice.

After the bismaleimide and diamine react, the acrylic resin is added in a heated atmosphere at 80 to 120°C to obtain the pressure-sensitive adhesive of the present invention.

The ratio of acrylic resin to aminobismaleimide is preferably in the range of 100 to 1000 parts by weight.
If the amount is less than 10 parts by weight, the adhesiveness will not be sufficient;
If the amount exceeds 0.00 parts by weight, the heat resistance of the adhesive will decrease.

The acrylic resin (b) used in the present invention must contain 15 to 35% by weight of acrylonitrile.

If 15% by weight is left undropped, adhesive strength and soldering heat resistance will decrease.6 As the acrylonitrile component increases, adhesive strength and soldering heat resistance will improve, but if it exceeds 35% by weight, flexibility will decrease. In order to achieve both sufficient adhesive strength and flexibility, the content is preferably 15 to 35% by weight. Examples of esters of alcohols having 5 or less carbon atoms and acrylic acid or methacrylic acid include 2-ethylhexyl acrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl acrylate.
-Ethylhexyl etc. Acrylic acid and/or
Alternatively, methacrylic acid needs to be 2 to 10% by weight. If it is less than 2% by weight, adhesive strength and soldering heat resistance will decrease. If it exceeds 10% by weight, flexibility decreases.

The above imide adhesives can be used as is, but flame retardants such as antimony trioxide, aluminum hydroxide, barium borate, brominated epoxy, silica alumina, mica, titanium oxide, zirconia, magnesium oxide, etc. The inorganic filler may be added in an amount of 40 parts by weight or less per 100 parts by weight of the adhesive. If it exceeds 40 parts by weight, the adhesive strength will decrease.

The adhesive of the present invention can be applied to one or both sides of a gold ME foil such as copper foil or aluminum foil, or a heat-resistant plastic film such as polyimide or polyester, and then dried by heating to obtain an adhesive tape.

The adhesive applied to these base materials is usually heated at 60-150°C.
Adhesive tape can be obtained by drying.

(Example) Example 1 First, 32 parts by weight of acrylonitrile, 100 parts by weight of n-butyl acrylate, and 3 parts by weight of acrylic acid were placed in a four-piece rosemovable flask equipped with a thermometer, a stirrer, a reflux condenser, and a dry nitrogen gas inlet. Parts by weight, toluene 400
A mixture consisting of parts by weight was reacted under a nitrogen atmosphere at 60° C. for 16 hours with stirring to obtain a viscous acrylic resin solution with a resin content of 25% by weight.

Then, in four rosemable flasks equipped with a thermometer, a stirrer, a reflux condenser, and a dry nitrogen gas inlet, 1,3-bis Add 1 mol of (3-aminophenoxy)benzene to make a total of 100 parts by weight,
Furthermore, 100 parts by weight of ethylene glycol monomethyl ether was taken, and after reacting at a temperature of 100°C for 3 hours, 400 parts by weight of the acrylic resin obtained above (resin content 25% by weight) was added.
was added, stirred at a temperature of 100°C for 1 hour, and then cooled.
A bismaleimide adhesive was obtained. Note that dry nitrogen gas was allowed to flow throughout the reaction from the preparation stage to product removal.

Example 2 After synthesizing the same acrylic resin as in Example 1, using the same equipment and method, 2
．． 2-bis(4-(4-aminophenoxy)phenyl)
Add 0.6 mol of propane to make a total of 100 parts by weight, take 100 parts by weight of N-methyl-2-pyrrolidone,
After reacting for 3 hours at a temperature of 100°C, 400 parts by weight of the previously obtained acrylic resin (resin content 25% by weight) was added, and 1
After stirring for 1 hour at a temperature of 00°C, the mixture was cooled to obtain a bismaleimide adhesive. Note that dry nitrogen gas was allowed to flow throughout the reaction from the preparation stage to product removal.

(Comparative Example) Comparative Example 1 In Example 1, 1.3-bis(3-
Add 0.3 moles of (aminophenoxy)benzene to make a total of 100 parts by weight, then add 100 parts by weight of ethylene glycol monomethyl ether, and stir at a temperature of 1° to 0°C.
When the solution was allowed to react for several hours, bismaleimide precipitated after cooling, and a uniform adhesive could not be obtained.

Comparative Example 2 The aminobismaleimide obtained in Example 1 was used as an adhesive without adding any acrylic resin.

The above bismaleimide adhesive solution was cast onto a 25 μm polyimide film (Kapton, manufactured by DuPont) so that the dry thickness would be 25 μm, and then placed in a dryer and dried at 120”C for 15 minutes. and adhesive tape,
Table 1 shows the results of evaluating the copper foil laminated adhesive tape with a thickness of 35 μm on the surface coated with the adhesive.

Table 1 (Effects of the invention) Conventional pressure-sensitive adhesives such as NBR/phenol resin, phenol resin/butyral resin, NBR/epoxy resin, and acrylic resin were unable to achieve both heat resistance and adhesiveness. By using imide-based adhesives, it has become possible to improve heat resistance without impairing other properties required of adhesive tapes, such as adhesiveness and flexibility.

*) JIS 6481

Claims (1)

[Claims] (1) An imide adhesive containing the following (a) and (b). (a) molar ratio of 1 to 0.5 to 1.
100 parts by weight of aminobismaleimide obtained by heat-reacting diamine No. 5 in an ether-based polar solvent (b) 15 to 35% by weight of acrylonitrile, 55 to 35% by weight of an ester of an alcohol having 5 or less carbon atoms and acrylic acid and/or methacrylic acid 10 to 1000 parts by weight of an acrylic resin obtained by copolymerizing 83% by weight and 2 to 10% by weight of acrylic acid and/or methacrylic acid