JPH10120785A - Polyimide resin composition and film adhesive and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition comprising two kinds of specific polyimide resins, exhibiting specified viscoelastic behaviors, capable of expressing excellent heat resistance, low temperature short time adhesivity and processability, and useful for film adhesives used for mounting semiconductors, etc. SOLUTION: This polyimide resin composition has two peaks in the temperature variance spectrum of loss elastic modulus and loss tangent on the measurement of dynamic viscoelasticity, and is soluble in organic solvents. For example, the polyimide resin composition is obtained by mixing a resin comprising repeating units of formula I [Ar1 is a tetravalent organic group; 30-100% of X1 is a group of formula II (R<1> -R<4> are each H, a monovalent organic group wherein at least one of R<1> -R<4> is not H), and the remainders are other divalent groups[ with a resin comprising repeating units of formula III (X2 is a divalent group excluding the group of formula II; Ar2 us Ar1 ) in an A/B weight ratio of 5/95 to 95/5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin and a film adhesive having both heat resistance and low-temperature processability, and having excellent adhesive strength to a silicon substrate, metal or resin suitable for electronic use, especially as a semiconductor mounting material. And its manufacturing method.

[0002]

2. Description of the Related Art Polyimide resins are widely used as electric and electronic materials because of their high heat resistance, flame retardancy and excellent electrical insulation. It is widely used as a film as a base material for flexible printed wiring boards and heat-resistant adhesive tapes, and as a resin varnish for insulating and protective films of semiconductors.
However, conventional polyimide resins have high hygroscopicity and excellent heat resistance, but are insoluble or infusible or have a very high melting point, and cannot be said to be materials which are easy to use in terms of workability. It is used as a semiconductor mounting material for interlayer insulating films and surface protection films.For these, a precursor polyamic acid soluble in an organic solvent is applied to the semiconductor surface, and the solvent is removed by heat treatment and imidization is performed. proceeding. At this time, the imidization requires a heating step at a high temperature of 300 ° C. or more for one hour or more, and the device is exposed to a high temperature, thereby lowering the yield of the assembly step. Further, since the film has high hygroscopicity, there is a problem that the absorbed water evaporates at a stretch at a high temperature and causes swelling and cracks.

In recent years, semiconductor chips have become larger due to higher functions and larger capacities. On the other hand, the package size has not changed from the conventional one due to restrictions on the design of printed circuits and demands for downsizing of electronic equipment. Have been. In response to this trend, several new mounting schemes have been proposed that correspond to higher density and higher density mounting of semiconductor chips. One is a COL that mounts a chip on a lead frame without a die pad proposed for memory devices.
There is a (chip-on-lead) structure and a LOC (lead-on-chip) structure in which leads are mounted on a chip, which is an advanced version thereof. On the other hand, a logic element has a multilayer lead frame structure in which a power supply and a ground are separated from each other and a metal plate for heat dissipation is multilayered. According to these, it is possible to rationalize the wiring in the chip and wire bonding, to increase the signal speed by shortening the wiring, to dissipate the heat generated due to the increase in power consumption, and to reduce the element size.

In this new mounting mode, there are bonding interfaces of the same kind and different materials, such as a semiconductor chip and a lead frame, a lead frame and a plate, and a lead frame, and the bonding reliability has a great influence on the reliability of the element. . This is not only the reliability that can withstand the process temperature during the element assembling work, but also the bonding reliability when absorbing moisture, when heating and the like. Further, the bonding workability is also an important item.

Conventionally, these adhesives have been used in the form of a paste-like adhesive or a heat-resistant substrate coated with an adhesive. Epoxy resin, acrylic resin, and rubber-phenol resin thermosetting resins are used as adhesives, but they contain many ionic impurities, require high temperature and long time for heat curing, and have poor productivity. At times, a large amount of volatile components are generated to contaminate the lead, and high hygroscopicity is not satisfied with the demand for a highly reliable adhesive, and no satisfactory material is found. There is a need to develop an adhesive suitable for a new mounting form. One of the methods is a hot-melt type film adhesive using a polyimide resin (see JP-A-5-105850, 112760, and 112761). With a hot-melt type adhesive, it is possible to thermocompression-bond to an adherend in a short time, eliminating the need for a heat-curing step after bonding, and greatly contributing to improvement in productivity and reliability. . However, due to the hot melt type, if the glass transition temperature of the adhesive resin is high, the processing requires a very high temperature, and there is a high possibility of causing thermal damage to the adherend. On the other hand, when the glass transition temperature is lowered by introducing a flexible group to impart low-temperature workability, there has been a problem that the heat resistance is lowered and thus the reliability is lowered.

[0006]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies to obtain a polyimide resin and a film adhesive having excellent workability such as heat resistance and low-temperature short-time adhesion. The inventors have found that the above problem can be solved by using a polyimide resin compound having the same, and have reached the present invention.

[0007]

SUMMARY OF THE INVENTION The present invention provides a polyimide resin composition soluble in an organic solvent, characterized in that a temperature dispersion spectrum of a loss elastic modulus and a loss tangent of dynamic viscoelasticity measurement has two peaks. The present invention also relates to a film adhesive containing the resin as a main component and a method for producing the same.

The polyimide resin of the present invention comprises a polyimide resin comprising a repeating unit represented by the general formula (1) and a polyimide resin comprising a repeating unit represented by the general formula (3):
Is a soluble polyimide resin mixed such that the weight ratio (1) / (3) is 5/95 to 95/5.

[0009]

Embedded image (Wherein, Ar ₁ is one or more tetravalent organic groups, and X ₁ is 30
-100% is one or more groups represented by the general formula (2), and the remainder is one or more other divalent groups)

[0010]

Embedded image (Wherein R ^{1 to} R ⁴ are a hydrogen atom or a monovalent organic group, and at least one of R ^{1 to} R ⁴ is not a hydrogen atom)

[0011]

Embedded image (In the formula, Ar ₂ is one or more tetravalent organic groups, and X ₂ is one or more divalent groups other than the general formula (2))

The polyimide resin (1) used in the present invention comprises:
A mole of one or more diamines represented by the formula (4), a b mole of one or more other diamines and a c mole of the amine represented by the general formula (5) are represented by an amine component represented by the general formula (6). D mole of at least one tetracarboxylic dianhydride as an acid component.
3 ≦ a / (a + b + 0.5c) ≦ 1.0 and 0 ≦ 0.5
c / (a + b + 0.5c) ≦ 0.1 and 0.95 ≦ d /
Polyamide acid obtained by reacting both components in a molar ratio of (a + b + 0.5c) ≦ 1.05 is heated and dehydrated in an organic solvent to form a polyimide resin soluble in an imide-closed organic solvent, or represented by formula (4). A mole of one or more diamines and b moles of one or more other diamines are represented by the amine component represented by the general formula (6):
And at least one kind of tetracarboxylic dianhydride d represented by the formula and e mol of the acid anhydride represented by the general formula (7) as an acid component, 0.3 ≦ a / (a + b) ≦ 1.0 and 0 ≦ 0.5e
/(D+0.5e)≦0.1 and 0.95 ≦ (d + 0.
A polyamic acid obtained by reacting both components at a molar ratio of 5e) / (a + b) ≦ 1.05 can be obtained by heating and dehydrating in an organic solvent to close the imide.

[0013]

Embedded image (Wherein R ^{1 to} R ⁴ are a hydrogen atom or a monovalent organic group, and at least one of R ^{1 to} R ⁴ is not a hydrogen atom)

[0014]

Embedded image (Where Y is a monovalent organic group)

[0015]

Embedded image (Wherein Ar ₂ is a tetravalent organic group)

[0016]

Embedded image (Where Z is

Embedded image One group selected from the group consisting of

The polyimide resin (3) comprises at least one kind of diamine different from the diamine represented by the formula (4) and f mol of the amine represented by the formula (5) as an amine component, And at least one kind of tetracarboxylic dianhydride represented by the following formula is used as an acid component, and 0 ≦ 0.5 g / (f + 0.5
g) ≦ 0.1 and 0.95 ≦ h / (f + 0.5g) ≦
A polyamic acid obtained by reacting both components at a molar ratio of 1.05 is heated and dehydrated in an organic solvent, and is different from a polyimide resin soluble in an organic solvent subjected to imide ring closure or a diamine represented by the formula (4). F mol of at least one kind of diamine is an amine component, hmol of at least one kind of tetracarboxylic dianhydride represented by the general formula (6) and acid anhydride i represented by the general formula (7)
Mole is an acid component, and 0 ≦ 0.5i / (h + 0.5i) ≦
0.1 and 0.95 ≦ (h + 0.5i) /f≦1.05
Can be obtained by heating and dehydrating a polyamic acid in which both components have been reacted in an organic solvent at a molar ratio of:

The film adhesive of the present invention is obtained by mixing a polyimide solution obtained by mixing two kinds of soluble polyimide resins having different glass transition temperatures in which a polyamic acid is heated and dehydrated in an organic solvent to complete imide ring closure. A film adhesive obtained by casting and drying on one side or both sides of a support.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The diamine represented by the formula (4) used in the present invention includes 4,4'-methylenedi-O-toluidine, 4,4'-methylenedi-2,6-xylidine,
4'-methylenedi-2,6-diethylaniline, 4,
4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane or the like, which contributes to the solubility of polyimide in organic solvents. By using a diamine having this structure, a polyimide resin soluble in an organic solvent having a Tg of 250 ° C. or higher can be easily synthesized. When a polyimide resin containing the diamine and a polyimide resin not containing the diamine are mixed, they are mixed uniformly in a solution state. However, when the solvent is removed by drying or the like, a microphase separation structure is exhibited. As a result, two peaks appear in a temperature dispersion spectrum of a loss elastic modulus and a loss tangent in a dynamic viscoelasticity measurement of a resin in which polyimides (1) and (3) having different glass transition temperatures are mixed in the above-described ratio. This characteristic greatly contributes to the high heat resistance, low temperature, and short-time adhesion, which is the subject of the present invention. The amount ratio is preferably 30 to 100 mol% of the total amine components of the polyimide resin (1). Resin viscoelasticity, development of microphase separation structure, heat resistance, low-temperature short-time adhesion, solubility Is preferred. When 4,4'-diaminodiphenylmethane in which all of R1 to R4 are hydrogen atoms, the obtained polyimide is not preferable because it is insoluble in an organic solvent. In particular, a case where two or more of R ^{1 to} R ⁴ are an alkyl group having 1 or 2 carbon atoms is more preferable in terms of solubility in an organic solvent.

Other diamine components used in the present invention include 2,2-bis (4- (4-aminophenoxy) phenyl) propane and 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoro Propane, 2,2-
Bis (4-aminophenoxy) hexafluoropropane, bis-4- (4-aminophenoxy) phenylsulfone, bis-4- (3-aminophenoxy) phenylsulfone, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene,
1,4-bis (3-aminophenoxy) benzene, 4,
4′-bis (4-aminophenoxy) biphenyl, 4,
4 '-(p-phenylenediisopropylidene) dianiline, 3,4-diaminodiphenyl ether, 4,4'-
Diaminodiphenyl ether, 3,4 diaminodiphenylsulfone, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 2,5 diaminotoluene, 2,4 diaminotoluene, 4,6-dimethyl-m-phenylenediamine, 2, 5-dimethyl-p-phenylenediamine, 2,4,6-trimethyl-m-phenylenediamine, 4,4′-diaminobenzanilide, 3,3′-dihydroxy-4,4′-diaminobiphenyl, 1,3 -Diaminocyclohexane, 1,4-diaminocyclohexane, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3'-dimethyl-dicyclohexylmethane, 4,4'-diamino-
3,3′-dimethyl-dicyclohexyl, 1,3-bis (3-aminopropyl) tetramethylsiloxane, α,
ω-bis (3-aminopropyl) polydimethylsiloxane, 1,3-bis (4-aminophenyl) tetramethylsiloxane, α, ω-bis (4-aminophenyl) polydimethylsiloxane, 1,3-bis (3 -Aminophenyl) tetramethylsiloxane, α, ω-bis (3-aminophenyl) polydimethylsiloxane, 1,3-bis (3-aminopropyl) tetraphenylsiloxane,
α, ω-bis (3-aminopropyl) polydiphenylsiloxane and the like can be mentioned, and these can be used alone or in combination of two or more.

In particular, the use of the diamine represented by the formula (8) can greatly improve the solubility and adhesion of the polyimide resin obtained. This is the 1,3-bis (3-
Aminopropyl) tetramethylsiloxane, α, ω-bis (3-aminopropyl) polydimethylsiloxane, etc., and the effect appears when the amount ratio is 2 mol% or more of the total amine components. In particular, when 1,3-bis (3-aminopropyl) tetramethylsiloxane is used, it is preferable since the adhesiveness can be largely improved without lowering the heat resistance of the obtained polyimide.

[0022]

Embedded image (R ⁵ and R ⁶ are monovalent hydrocarbon groups, R ⁷ is a divalent hydrocarbon group, and n is an integer of 1 to 20)

Further, by using the diamine represented by the formula (9), it is possible to improve the adhesiveness while maintaining high Tg and solubility of the obtained polyimide resin. These are 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane, 2,2-bis (4-aminophenoxy) ) Hexafluoropropane,
Bis-4- (4-aminophenoxy) phenylsulfone, bis-4- (3-aminophenoxy) phenylsulfone, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene,
1,4-bis (4-aminophenoxy) benzene, 1,
4-bis (3-aminophenoxy) benzene, 4,4 ′
-Bis (4-aminophenoxy) biphenyl and the like, and the effect is exhibited when the amount ratio is 5 mol% or more of all amine components.
In particular, 2,2-bis (4- (4-aminophenoxy) phenyl) propane is preferable because Tg can be kept high.
1,3-Bis (3-aminophenoxy) benzene is preferred in that it improves the adhesiveness.

[0024]

Embedded image (Ar ₃ is a divalent organic group)

The acid dianhydride used in the present invention is 3,3 ′,
4,4′-biphenyltetracarboxylic dianhydride, 3,
3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic dianhydride, 4,4′-oxydiphthalic dianhydride, 2,2 ′ , 3,3'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-benzophenonetetracarboxylic dianhydride, pyromellitic anhydride, 4,4'
-(Hexafluoroisopropylidene) phthalic anhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,7-naphthalenetetracarboxylic dianhydride, 1,2,5 , 6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-naphthalenetetracarboxylic dianhydride, and the like. These may be used alone or as a mixture of two or more. From the viewpoints of heat resistance and solubility in organic solvents, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, , 3 ', 4,4'
-Diphenylsulfonetetracarboxylic dianhydride, 4,
It is preferable to use one or more acid dianhydrides selected from the group consisting of 4'-oxydiphthalic dianhydride. In particular, for applications requiring heat resistance, it is preferable to use pyromellitic anhydride.

When the polyimide is used as an adhesive, by controlling the molecular weight by end-capping the molecular terminals, it is possible to obtain a melt viscosity suitable for adhesion to an adherend, improve wettability and improve adhesion. Power can be increased. It is preferable that the number of functional groups of the acid anhydride or amine serving as an end cap agent is 10% or less of the number of functional groups of all amine components or all acid components. If it is larger than this range, the molecular weight is remarkably reduced, which causes a problem in heat resistance and film formability. Further, from the viewpoint of low-temperature adhesion, heat resistance, and mechanical strength, it is more preferable that the number of functional groups of the end cap agent is in the range of 0.5 to 5% of the number of functional groups of all acidic components or all amine components. Further, from the viewpoint of heat resistance of the obtained resin, it is necessary to use only one of an amine and an acid anhydride as an end cap agent.

Examples of the endcapping agent include an amine represented by the general formula (5) and an acid anhydride represented by the general formula (7). Examples of acid anhydrides include phthalic anhydride, maleic anhydride, nadic anhydride, and hexahydrophthalic anhydride. Examples of amines include p-methylaniline, p-methoxyaniline, p-phenoxyaniline, allylamine, methoxypropylamine, and ethoxy. Propylamine or the like is used.

The equivalent ratio of the acidic component to the amine component in the polymerization reaction is an important factor that determines the molecular weight of the obtained polyamic acid. It is well known that there is a correlation between the molecular weight and physical properties of a polymer, especially the number average molecular weight and mechanical properties. The higher the number average molecular weight, the better the mechanical properties. Therefore, in order to obtain practically excellent strength, it is necessary to have a high molecular weight to some extent. In the present invention, the equivalent ratio r between the acidic component and the amine component is preferably a molar ratio of 0.95 ≦ r ≦ 1.05. 0.97 ≦ r ≦ 1.0
The range of 3 is more preferable in terms of both mechanical strength and heat resistance.

In the present invention, a polyimide resin consisting of a repeating unit represented by the general formula (1) and a polyimide resin consisting of a repeating unit represented by the general formula (3) are used in a weight ratio of (1) to (3).
/ (3) is from 5/95 to 95/5, but from the viewpoint of achieving both heat resistance and low-temperature workability, the ratio is from 20/80 to 95/95.
A range of 80/20 is more preferred.

In a field where high heat resistance, high elastic modulus, and low-temperature short-time bonding are strongly required, it is preferable that the glass transition temperature of the polyimide resin (1) is higher than the glass transition temperature of the polyimide (3). It is more preferable that the difference be 30 ° C. or more from the viewpoint of low-temperature adhesiveness.

The reaction between the tetracarboxylic dianhydride and the diamine is carried out by a known method in an aprotic polar solvent. Aprotic polar solvents include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (D
MAC), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), diglyme, cyclohexanone, gamma-butyrolactone (GBL), 1,4-
And dioxane (1,4-DO). As the aprotic polar solvent, only one kind may be used, or two or more kinds may be used as a mixture. At this time, a non-polar solvent compatible with the aprotic polar solvent may be mixed and used. Aromatic hydrocarbons such as toluene, xylene, and solvent naphtha are often used. The proportion of the non-polar solvent in the mixed solvent is preferably 30% by weight or less.
This is because if the nonpolar solvent is 30% by weight or more, the solvent power of the solvent may be reduced and polyamic acid may be precipitated. The reaction between the tetracarboxylic dianhydride and the diamine is
The well-dried diamine component is dissolved in the above-mentioned dehydrated and purified reaction solvent, and the ring closure ratio is 98%, more preferably 99%.
The above-mentioned well-dried tetracarboxylic dianhydride is added to proceed the reaction.

The polyamic acid solution thus obtained is subsequently heat-dehydrated and cyclized in an organic solvent to give imidized polyimide. Since the water generated by the imidization reaction interferes with the ring closure reaction, an organic solvent incompatible with water is added to the system and azeotroped, and the system is removed from the system using a device such as a Dean-Stark tube. To be discharged. Dichlorobenzene is known as an organic solvent incompatible with water,
For the purpose of electronics, the above-mentioned aromatic hydrocarbon is preferably used because there is a possibility that a chlorine component may be mixed.
Further, it does not prevent the use of compounds such as acetic anhydride, β-picoline, and pyridine as a catalyst for the imidization reaction.

In the present invention, the higher the degree of imide ring closure, the better the degree of imidization. If the rate of imidization is low, imidization occurs due to heat during use to generate water, which is not preferable. Therefore, 95% or more, more preferably 98% or more. Is preferably achieved.

In the present invention, the obtained polyimide solution can be used as it is. Alternatively, the polyimide solution may be put into a poor solvent to reprecipitate and precipitate the polyimide resin to remove and purify unreacted monomers, and the dried product may be dissolved in an organic solvent and used again. In particular, in applications that dislike volatiles, impurities, foreign substances, and the like, it is preferable to filter and use the polyimide solution thus produced.
The solvent used at this time is preferably a solvent having a low boiling point in consideration of workability.

The two kinds of polyimide solutions thus obtained can be easily mixed with a stirrer. However, the solvent used must dissolve both polyimides.

Various additives such as a smoothing agent, a leveling agent, and a defoaming agent for improving the surface smoothness can be added to the resin varnish as needed. In addition, an aromatic hydrocarbon-based solvent can be used within a range in which the solvent is uniformly dissolved in order to adjust the evaporation rate of the solvent.

The method of use and application of the polyimide resin of the present invention are not particularly limited, but it is also possible to use a resin varnish as it is for coating or dipping, or to cast a varnish and then dry it to form a film. . It is also possible to use it as a solid resin for extrusion molding. Examples of a method for solidifying the solid include reprecipitation in a poor solvent.

In the present invention, a resin varnish is used as a film adhesive by casting or coating a resin varnish. For example, a heat-resistant film base material is used as a support, and a film layer is similarly formed on one or both surfaces thereof. To form a film adhesive on a release sheet such as a roll, a metal sheet, or a polyester sheet using a flow coater or a roll coater. It can be obtained by a method such as a film adhesive. The heat-resistant film substrate used in the present invention is such that the polyimide resin film has a small coefficient of thermal expansion and is excellent in dimensional stability against temperature changes, is flexible and easy to handle, and has an adhesive force with the resin of the present invention. Is preferable in that it is excellent. In particular, a polyimide resin having a glass transition temperature of 350 ° C. or more is excellent in workability and stability in a step of drying a coating varnish.

The base film used for producing a single-layer film adhesive is required to have a heat resistance of the release agent and the base material which is higher than the drying temperature. The substrate is preferably a polyethylene terephthalate film, a polyethylene naphthalate film, a polyimide film, a polyphenylene sulfide film, an aluminum foil, or a stainless steel film. As the release agent, a hydrocarbon-based release agent has insufficient heat resistance, and is preferably a heat-resistant resin such as silicone, silicone-modified epoxy, or fluororesin. In particular, when a solvent having a high boiling point is used or when a polyimide resin having a high glass transition temperature is formed into a film, a drying temperature of 250 ° C. or more may be required. In such a case, it is preferable to use an aluminum foil for the base material in terms of heat resistance and cost. At this time, the release agent is preferably a fluororesin such as polytetrafluoroethylene (PTFE) from the viewpoint of heat resistance and releasability, and is preferably a silicone modified epoxy from the viewpoint of adhesion between the aluminum foil and the release agent. The application and drying of the resin varnish can be performed using an apparatus in which an application facility such as a flow coater or a roll coater is combined with a hot-air drying oven. After applying the resin varnish to the support, the resin varnish is guided to a hot-air drying oven and dried at a temperature and air volume sufficient to evaporate the solvent of the varnish. How to use the film adhesive of the present invention is not particularly limited,
It can be used as an adhesive tape, such as by cutting into a predetermined shape and thermocompression bonding with a heated heat block and bonding.

The polyimide resin of the present invention is characterized by mixing two kinds of almost completely imidized polyimide resins having different glass transition temperatures which are soluble in an organic solvent. By limiting the composition and mixing ratio of the two kinds of polyimide resins, the resin from which the solvent has been removed can exhibit a microphase-separated structure, and a special viscoelasticity can be obtained. That is, only the blend of the polyimide resin composed of the repeating unit of the above general formula (1) and the polyimide resin composed of the repeating unit of the general formula (3), that is, the structure not having the general formula (1) exhibits a microphase-separated structure and is dynamic. Two peaks appear in the temperature dispersion spectrum of the loss elastic modulus and the loss tangent of the viscoelasticity measurement. This makes it possible to achieve both high heat resistance and low temperature processability of the resin. In other systems, that is, a blend of the general formulas (1), a blend of the non-general formulas (1), or a single polyimide resin which is not blended, a microphase-separated structure cannot be obtained and this performance cannot be enjoyed.

Particularly when the polyimide resin of the present invention is used as a film adhesive, it exhibits excellent properties such as high heat resistance, high elastic modulus, and low-temperature short-time adhesion. Bonding can be performed in an extremely short time as compared with a thermosetting adhesive involving a chemical reaction. Further, by processing into a film, the bonding workability and the dimensional accuracy of the bonded portion can be improved. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0042]

The present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Abbreviations in Examples and Comparative Examples are as follows. PI: Polyimide MDT: 4,4'-methylenedi-O-toluidine MDX: 4,4'-methylenedi-2,6-xylidine DDM: 4,4'-diaminodiphenylmethane BAPP: 2,2-bis (4- (4 -Aminophenoxy) phenyl) propane APB: 1,3-bis (3-aminophenoxy) benzene BAPS: bis-4- (4-aminophenoxy) phenylsulfone APDS: 1,3-bis (3-aminopropyl) tetramethyl Siloxane APPS: α, ω-bis (3-aminopropyl) polydimethylsiloxane (average molecular weight 837) 25 DPX: 2,5-dimethyl-p-phenylenediamine PPA: p-phenoxyaniline BPDA: 3,3 ′, 4,4 '-Biphenyltetracarboxylic dianhydride BTDA: 3,3', 4,4'-benzo Enone tetracarboxylic dianhydride ODPA: 4,4'-oxydiphthalic dianhydride DSDA: 4,4'-diphenylsulfonetetracarboxylic dianhydride PMDA: pyromellitic anhydride PA: phthalic anhydride NMP: N- Methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide (DMAC) GBL: gamma-butyrolactone

(Synthesis of polyimide resin PI-1) 391 g of dehydrated and purified DMAc was placed in a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, a thermometer, and a stirrer, and stirred vigorously for 10 minutes while flowing nitrogen gas. Next, 45.264 g (0.200 mol) of MDT, which is an amine component, is charged, and the system is heated to 60 ° C. and stirred until uniform. After uniformly dissolving, the system was cooled to 5 ° C. in an ice water bath, and ODPA (63.285 g (0.204 mol)) as an acid component was added over 10 minutes while keeping the powdery state. I got During this time, the flask was kept at 5 ° C.

After that, remove the nitrogen gas inlet pipe and the cooler,
A Dean-Stark tube filled with toluene was attached to the flask, and 43 g of toluene was added to the system. The system was heated by replacing the ice water bath with an oil bath, and the generated water was removed from the system. After heating for 4 hours, no water was generated from the system. After cooling, the reaction solution was poured into a large amount of methanol to precipitate a polyimide resin. After filtering the solids, 80
Drying under reduced pressure at 12 ° C. for 12 hours gave a solid resin. When the infrared absorption spectrum was measured by the KBr tablet method, an absorption of 5.60 μm derived from the cyclic imide bond was recognized, but an absorption of 6.06 μm derived from the amide bond could not be recognized. 100% imidization was confirmed.

The polyimide resin obtained in this manner was treated with DM
Ac was dissolved in Ac to prepare a polyimide resin varnish having a solid content of 20% by weight.

(Synthesis of Polyimide Resin PI-2 to 15)
PI-2 to PI-15 were synthesized in the same manner as in the synthesis of PI-1 by mixing the amine component and the acid component shown in Table 1. P
The concentrations of I were all adjusted to 20 wt% with the solvents shown in Table 1.

[0047]

[Table 1]

Example 1 A glass flask was charged with 140 g of polyimide resin PI-1 and 60 g of PI-11, and sufficiently stirred to obtain a uniform blend solution. This solution was subjected to a silicone release biaxially oriented polyester film (trade name: Diafoil MR, thickness: 1) using a reverse roll coater.
00 μm, manufactured by Mitsubishi Rayon Co., Ltd.)
After drying for 30 minutes with a silicone mold release treatment, the film was peeled off from the biaxially stretched polyester film to obtain a 30 μm-thick uniform transparent single-layer film adhesive without a support. Peeling was easy and there was no particular problem. When a thermal stress distortion measurement (hereinafter abbreviated as TMA measurement) of this film was performed in a tensile mode, a glass transition temperature (hereinafter abbreviated as Tg) was 280 ° C. When Tg of each of PI-1 and PI-11 was measured by the same method, they were 295 ° C and 140 ° C, respectively.

The dynamic viscoelasticity of the film of the blend was measured in a tensile mode. The temperature dispersion curves of the loss elastic modulus (hereinafter abbreviated as E ″) were 165 ° C. and 290 ° C.
In addition, two peaks which are considered to correspond to two glass transitions at 165 ° C. and 310 ° C., respectively, of a temperature dispersion curve of a loss tangent (hereinafter abbreviated as tan δ) were observed. This suggests that a microphase-separated structure exists in the film.

The above-mentioned blend solution was applied to one surface of a polyimide film (trade name: Upilex SGA, thickness: 50 μm, manufactured by Ube Industries, Ltd.) in the same manner as above to obtain an adhesive tape having an adhesive layer thickness of 30 μm. . This adhesive tape was thermocompression-bonded to a 42-alloy plate to prepare a test piece. The bonding temperature was 280 ° C, which is the Tg of the film, and 3
The run was performed at 310 ° C, 0 ° C higher and 340 ° C, 60 ° C higher.
Pressure bonding time is 2 seconds, pressure applied to the bonding surface is 4 kgf / cm
It was 2. The 180 degree peel strength of this test piece is 1.5 kgf / kg when the bonding temperature is Tg of the film (280 ° C.).
cm, Tg + 30 ° C. (310 ° C.) 1.4 kgf /
cm, Tg + 60 ° C. (340 ° C.) 1.4 kgf /
cm, and exhibited excellent adhesive strength in a wide temperature range from a low temperature around Tg to a high temperature.

(Examples 2 to 9) Table 2 shows the results of the same evaluation as in Example 1.

[0052]

[Table 2]

(Comparative Examples 1 to 7) A blend solution was prepared in the same manner as in Example 1 with the composition shown in Table 3, and a film was obtained in the same manner as in Example 1, and the same evaluation was performed. Table 3 shows the obtained evaluation results.

[0054]

[Table 3]

Even when PI is used alone without blending as in Comparative Examples 1 and 2, or when blended as in Comparative Examples 3, 4, and 6, each raw material satisfies the conditions such as the above quantitative ratio. If not, the temperature dispersion curves of E ″ and tan δ in the viscoelasticity measurement each had only one peak, and the adhesive strength at a low temperature around Tg was not exhibited. In this case, PI-7 and PI-10 did not satisfy the above-mentioned ratio, and the solubility was poor and a uniform solution could not be obtained.

From the above examples, it can be seen that a polyimide resin which is soluble in an organic solvent and has excellent low-temperature processability and heat resistance and a heat-resistant film adhesive which can be bonded at a low temperature for a short time can be obtained from the resin according to the present invention. Is shown.

[0057]

According to the present invention, it is possible to provide a heat-resistant film adhesive which can be bonded to a polyimide resin having excellent low-temperature processability and heat resistance at a low temperature for a short time. Since it is soluble in a solvent and has already been imidized, a high-temperature process for imidization is unnecessary during processing, and no water is generated. Also, since it can be used as a tack-free film, it is very effective when continuous workability and a clean environment are required. For this reason, it is extremely useful industrially as a material for electronics requiring high reliability and heat resistance.

Claims (19)

[Claims] 1. A polyimide resin composition soluble in an organic solvent, wherein a temperature dispersion spectrum of a loss elastic modulus and a loss tangent of dynamic viscoelasticity measurement has two peaks. 2. A weight ratio (1) / (3) of a polyimide resin comprising a repeating unit represented by the general formula (1) and a polyimide resin comprising a repeating unit represented by the general formula (3):
2. The polyimide resin composition soluble in an organic solvent according to claim 1, wherein the composition is mixed so as to be 5/95 to 95/5. Embedded image (Wherein, Ar ₁ is one or more tetravalent organic groups, and X ₁ is 30
-100% is one or more groups represented by the general formula (2), and the remainder is one or more other divalent groups. (Wherein R ^{1 to} R ⁴ are a hydrogen atom or a monovalent organic group and at least one of R ^{1 to} R ⁴ is not a hydrogen atom). (In the formula, Ar ₂ is one or more tetravalent organic groups, and X ₂ is one or more divalent groups other than the general formula (2)) 3. The polyimide resin (1) comprises at least one kind of diamine amol represented by the formula (4), at least one kind of other diamine b mol and an amine c represented by the general formula (5). Is an amine component, and d mol of at least one tetracarboxylic dianhydride represented by the general formula (6) is an acid component, and 0.3 ≦ a / (a
+ B + 0.5c) ≦ 1.0 and 0 ≦ 0.5c / (a + b)
+ 0.5c) ≦ 0.1 and 0.95 ≦ d / (a + b +
The organic solvent according to claim 2, which is a polyimide resin soluble in an organic solvent obtained by heating and dehydrating a polyamic acid obtained by reacting both components in an organic solvent at a molar ratio of 0.5c) ≤ 1.05 to cause imide ring closure. Polyimide resin composition soluble in water. Embedded image (In the formula, R ^{1 to} R ⁴ are a hydrogen atom or a monovalent organic group, and at least one of R ^{1 to} R ⁴ is not a hydrogen atom.) (Wherein Y is a monovalent organic group) (Where Ar is a tetravalent organic group) 4. The polyimide resin (1) comprises one or more amoles of diamine represented by the formula (4) and one or more mols of other diamines b as an amine component represented by the general formula (6). D mol of one or more tetracarboxylic dianhydrides and a compound of the general formula (7)
The acid anhydride is represented by the following formula:
(A + b) ≦ 1.0 and 0 ≦ 0.5e / (d + 0.5
e) ≦ 0.1 and 0.95 ≦ (d + 0.5e) / (a +
4. The organic solvent according to claim 2, wherein b) is a polyimide resin soluble in an organic solvent obtained by heating and dehydrating a polyamic acid obtained by reacting both components at a molar ratio of ≦ 1.05 to form an imide ring closure. Polyimide resin composition soluble in water. Embedded image (Where Z is One group selected from the group consisting of 5. The organic solvent according to claim 2, wherein at least two of R ^{1 to} R ^{4 in} the formulas (2) and (4) are an alkyl group having 2 or less carbon atoms. Soluble polyimide resin composition. 6. Ar of tetracarboxylic dianhydride represented by the general formula (6) used for the polyimide resin (1) is represented by the following formula: And at least one diamine represented by the general formula (8), wherein at least one of the groups is selected from the group consisting of: 2. A polyimide resin composition soluble in the organic solvent according to item 1. Embedded image (R ⁵ and R ⁶ are monovalent hydrocarbon groups, R ⁷ is a divalent hydrocarbon group, and n is an integer of 1 to 20) 7. Formula (8) used for polyimide resin (1)
Is a diamine represented by 1,3-bis (aminopropyl)
The polyimide resin composition soluble in an organic solvent according to any one of claims 2 to 6, which is tetramethylsiloxane. 8. The method according to claim 2, wherein 5 to 70 mol% of all amine components used in the polyimide resin (1) is at least one diamine represented by the general formula (9). Polyimide resin composition soluble in organic solvents. Embedded image (Ar3 is a divalent organic group) 9. Formula (9) used for polyimide resin (1)
Is 2,2-bis (4- (4-aminophenoxy) phenyl) propane and / or 1,3
The polyimide resin composition soluble in an organic solvent according to any one of claims 2 to 8, which is -bis (3-aminophenoxy) benzene. 10. The polyimide resin (3) comprises one or more kinds of diamines different from the diamine represented by the formula (4), and f mol of an amine represented by the general formula (5) as an amine component. 6 mol) of at least one tetracarboxylic dianhydride represented by 6) as an acid component, and 0 ≦ 0.5 g / (f + 0.5
g) ≦ 0.1 and 0.95 ≦ h / (f + 0.5g) ≦
Polyimide acid obtained by reacting both components at a molar ratio of 1.05 is a polyimide resin that is soluble in an organic solvent which is heated and dehydrated in an organic solvent to form an imide ring, and is a polyimide resin. Polyimide resin composition soluble in organic solvents. 11. The polyimide resin (3) comprises one or more kinds of diamines different from the diamine represented by the formula (4) in an amine component, and one or more tetracarboxylic acids represented by the general formula (6). H mol of dianhydride and i mol of the acid anhydride represented by the general formula (7) are used as an acid component, and 0 ≦ 0.5i / (h + 0.
5i) ≦ 0.1 and 0.95 ≦ (h + 0.5i) / f ≦
Polyimide acid obtained by reacting both components at a molar ratio of 1.05 is a polyimide resin that is soluble in an organic solvent which is heated and dehydrated in an organic solvent to form an imide ring, and is a polyimide resin. Polyimide resin composition soluble in organic solvents. 12. The tetracarboxylic dianhydride represented by the general formula (6) used for the polyimide resin (3), wherein Ar is And at least one group selected from the group consisting of 2 to 100 mol% of all amine components represented by the general formula (8)
The polyimide resin composition soluble in an organic solvent according to any one of claims 2 to 11, which is at least one kind of diamine. 13. The organic compound according to claim 2, wherein the diamine represented by the formula (8) used for the polyimide resin (3) is 1,3-bis (aminopropyl) tetramethylsiloxane. A polyimide resin composition that is soluble in a solvent. 14. A compound represented by the general formula (9) wherein 5 to 100 mol% of all amine components used in the polyimide resin (3) is represented by the general formula (9).
The polyimide resin composition soluble in an organic solvent according to any one of claims 2 to 13, which is at least one kind of diamine. 15. The diamine represented by the formula (9) used for the polyimide resin (3) is 2,2-bis (4- (4-
The polyimide resin composition soluble in an organic solvent according to any one of claims 2 to 14, which is aminophenoxy) phenyl) propane and / or 1,3-bis (3-aminophenoxy) benzene. 16. The organic solvent according to claim 2, wherein the glass transition temperature of the polyimide resin (1) is higher than that of the polyimide resin (3) by 30 ° C. or more. Polyimide resin composition. 17. A film adhesive comprising the polyimide resin according to claim 1 as a main component. 18. Polyamide acid having a different glass transition temperature obtained by heating and dehydrating a polyamic acid in an organic solvent to complete imide ring closure.
18. The method for producing a film adhesive according to claim 17, wherein a polyimide solution obtained by mixing various kinds of soluble polyimide resins in a solution state is cast on one or both sides of the support and dried. 19. The method according to claim 17, wherein the polyamic acid is heated and dehydrated in an organic solvent, and an organic solvent solution of a polyimide resin in which imide ring closure is completed is cast on one surface of the support, dried, and then peeled from the support. Production method of film adhesive.