JPH09302091A - Novel high-elasticity polyimide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a novel high-elasticity polyimide resin compsn. which has specified water absorption, storage modulus, and glass transition point and is excellent in fusion bonding properties. SOLUTION: A polyimide resin comprising repeating units represented by formulas III and IV [wherein R1 and R2 are each a divalent org. group; R3 is a tetravalent org. group; and X is a trivalent org. group represented by formula V] and having a water absorption of 1% or lower, a storage modulus of 0.5-2.0GPa at 240 deg.C, a glass transition point of 200-350 deg.C, and a number-average mol.wt. of about 100.000 or higher is obtd. by dissolving an ester acid dianhydride represented by formula I and a tetracarboxylic dianhydride represented by formula II (wherein R3 and R4 are each a tetravalent org. group) in a solvent (e.g. dimethylformamide), adding a diamine e.g. 2,2-bis[4-(4- aminophenoxy)phenyl]propane} to the resultant soln., reacting the dianhydrides with the diamine at about -5 to 20 deg.C for 0.5-6hr, evaporating the solvent to give a polyamic acid copolymer, and thermally treating the copolymer at about 200-350 deg.C to imidize it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel polyimide, and more specifically, it has a glass transition point in an appropriate temperature range so that it can be heat-sealed, and a laminated film for insulating coating and a flexible printed circuit board ( Below, FPC
Abbreviated. ), A cover / coverlay film, a bonding sheet, a cover coat ink, a lead-on-chip, a lead frame fixing tape, and the like, and a novel polymer composition having excellent flexibility. More specifically, along with these described features,
Furthermore, the present invention relates to a novel copolymer composition characterized by satisfying both low water absorption and dielectric properties.

[0002]

2. Description of the Related Art In recent years, electronic devices have been further improved in performance, function and size, and accordingly, electronic components used have been required to be reduced in size and weight. As for a wiring board for mounting electronic parts, a flexible printed wiring board having flexibility is attracting attention as compared with a usual rigid material, and demand for the wiring board is rapidly increasing.

On the other hand, in general, a polyimide film is widely used as a material especially for electric / electronic devices because of its excellent heat resistance / low temperature characteristics, chemical resistance / electric characteristics and the like. However, since polyimides used for film applications are generally insoluble and infusible, when used for fusing and coating applications, a thermoplastic or thermosetting resin is applied to the polyimide film to impart adhesion. doing.

One of the thermoplastic resins that have been widely used in the past for the purpose of imparting this adhesiveness is, for example, a fluororesin such as FEP. An epoxy resin or the like is used as the thermosetting resin.

[0005]

However, while the fluororesin has relatively high heat resistance, excellent chemical resistance, and excellent low temperature characteristics, it has extremely poor radiation resistance, so that it is not suitable for the above-mentioned specific applications. It was unsuitable.

Further, thermosetting resins such as epoxy resin are
When curing, a high temperature, especially a long curing time is required, which is not suitable for these applications.

In view of the above situation, development of a film which can be processed in a short time, has excellent chemical resistance, low temperature characteristics, adhesiveness, and further has excellent heat fusion property with excellent electric characteristics is awaited. Was there.

Further, in place of the conventional thermosetting paste type die bond tape, a film-shaped laminating tape using a thermoplastic resin is being studied. This is being studied because it has the advantages of no outgassing due to no low-molecular-weight volatile components and no need for aftercure. Further, it is desired that these tapes do not have package cracks during molding due to moisture absorption and have a low dielectric constant for high-speed arithmetic processing.
Further, when using these novel tape adhesives, it has been recently pointed out that if they do not have an appropriate heat storage adiabatic rate, so-called adhesive sagging causes die bond failure. .

[0009] Therefore, the present inventors have solved the above-mentioned conventional problems, can process in a short time, and have chemical resistance and
As a result of intensive studies conducted for the purpose of providing a material which is excellent in low-temperature characteristics, adhesiveness, low water absorption characteristics, and further excellent in electric characteristics and can be suitably used for the above-mentioned applications, the present invention has been achieved. is there.

[0010]

The gist of the novel highly elastic polyimide resin composition according to the present invention for achieving this object is that the storage elastic modulus at 240 ° C. is 0.5 to 2.0 GPa or more. With a glass transition temperature of 200 ° C. to 3
It is 50 ° C. and consists of a thermoplastic resin having a water absorption rate of 1% or less.

The composition of the thermoplastic resin is represented by the general formula (1)

[0012]

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And the general formula (2):

[0014]

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(Wherein R ₁ and R ₂ are divalent organic groups, R ₃
Is a tetravalent organic group, X is

[0016]

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It is a trivalent linking group selected from: ) Is composed of both repeating units.

Further, the above general formulas (1) and (2)
Molar fraction of repeating unit represented by [(1) / (2)]
Is in the range of 95/5 to 5/95.

Further, R ₂ in the general formulas (1) and (2) is

[0020]

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It is at least one selected from the group of divalent organic groups shown in.

Further, R ₁ in the general formula (1) is

[0023]

[Chemical 12]

(Wherein R ₄ is a divalent organic group) is at least one selected from the organic groups shown below.

Further, R ₃ in the general formula (2) is

[0026]

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It is at least one selected from the group of tetravalent organic groups shown in.

Further, R ₄ of R _{1 in} the general formula (1) is

[0029]

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At least one selected from the organic groups shown in
It is to be a seed.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The novel highly elastic polyimide resin composition according to the present invention has a storage elastic modulus of 0.5 to 2.0 GPa or more at 240 ° C and a glass transition temperature of 200 ° C to 35 ° C.
It is 0 ° C. and consists of a thermoplastic resin having a water absorption rate of 1% or less. More specifically, in general formula (1),

[0032]

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And the general formula (2):

[0034]

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(Wherein R ₁ and R ₂ are divalent organic groups, R ₃
Is a tetravalent organic group, and X is

[0036]

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It is a trivalent linking group selected from ), And has excellent heat resistance, processability, low water absorption property, and dielectric property. Here, it must have both the repeating unit represented by General formula (1) and General formula (2).

The method for producing a novel high-elasticity polyimide resin assembly according to the present invention will be described below. First, a diamine represented by the general formula (3) HN ₂ —R ₂ —NH ₂ (3) (wherein R ₂ represents a divalent organic group) in an atmosphere of an inert gas such as argon or nitrogen. Is dissolved or diffused in an organic solvent. In this solution, the compound of the general formula (4)

[0039]

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(Wherein R ₄ represents a divalent organic group) and an ester dianhydride represented by the general formula (5)

[0041]

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A mixture of at least one tetracarboxylic dianhydride represented by the formula (wherein R ₃ represents a tetravalent organic group) is added in a solid state or in an organic solvent solution,
A solution of polyamic acid copolymer is obtained.

The reaction temperature at this time is preferably -10 ° C to 50 ° C, more preferably -5 ° C to 20 ° C. The reaction time is 30 minutes to 6 hours.

In this reaction, contrary to the above addition procedure, first, a mixture of an ester acid dianhydride and a tetracarboxylic acid dianhydride is dissolved or diffused in an organic solvent, and the solid of the diamine is dissolved in the solution. Alternatively, a solution or slurry of an organic solvent may be added.

In this case, the ratio of the acid dianhydride component is the molar ratio of the ester acid dianhydride represented by the general formula (4) and the tetracarboxylic dianhydride represented by the general formula (5). Is preferably in the range of 95/5 to 5/95. Further, the diamine represented by the general formula (3) is
It is preferable to use the same molar amount as the total amount of the dianhydride component.

Next, in order to obtain a polyimide copolymer from the solution of the polyamic acid copolymer, a method of thermally and / or chemically performing dehydration ring closure (imidization) may be used.

Explaining with an example, in the method of thermally dehydrating and ring-closing, first, the above polyamic acid solution is added to a supporting plate or P
A film having a self-supporting property is obtained by casting or coating on a support such as an organic film such as ET or a drum or an endless belt to form a film, and evaporating the organic solvent. The evaporation of the organic solvent is about 50 to 90 at a temperature of 150 ° C or lower.
Minutes.

Next, this is further heated and dried to be imidized to obtain a polyimide film made of the thermoplastic polyimide copolymer of the present invention. The temperature during heating is 150 to 3
Temperatures in the range of 50 ° C are preferred, especially 200-250.
C is especially preferred. There is no limitation on the rate of temperature increase during heating, but it is preferable that the maximum temperature reaches the above temperature by gradually heating. Although the heating time varies depending on the film thickness and the maximum temperature, it is generally preferably in the range of 10 seconds to 10 minutes after the maximum temperature is reached. When the film having self-supporting property is heated and dried / imidized, the film having self-supporting property is peeled from the support, and the end portion is fixed in that state and the polyimide is heated to have a small linear thermal expansion coefficient. A polyimide film made of a copolymer is obtained.

Further, in the method of chemically dehydrating and ring-closing, a dehydrating agent in a stoichiometric amount or more and a catalytic amount of a tertiary amine are added to the above polyamic acid solution and treated in the same manner as in the case of thermally dehydrating. A desired polyimide film can be obtained in a shorter time than in the case of thermally dehydrating and ring-closing.

Comparing the thermal imidization method and the chemical imidization method, the chemical method has the advantage that the polyimide obtained has a higher mechanical strength and a smaller coefficient of linear thermal expansion. is there. In addition, it is also possible to use both the method of thermally imidizing and the method of chemically imidizing together.

It is well known that polyimide is an equivalent to polyisoimide, but it is possible to improve the solvent solubility by selecting an isoimide structure.
In order to obtain a polyisoimide copolymer, the reactants in the above-mentioned polyimide formation, that is, diamine and tetracarboxylic dianhydride, are added to dicyclocarbodiimide (D
CC) or another diimide and / or carboxylic acid such as trifluoroacetic acid may be replaced with the same reaction as in the formation of the polyimide.

Here, as the diamine compound represented by the general formula (3) used in the present invention, various diamines can be essentially used, but more specifically,
From the viewpoint of the balance of various characteristics, the general formula (3) HN ₂ —R ₂ —NH ₂ (3) (R ₂ in the formula is

[0053]

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A bisaminophenoxyphenylpropane, bisaminophenoxybenzene, diaminodiphenyl ether, phenylenediamine, bisaminophenoxybiphenyl, bisaminophenoxyphenyl ether, It is possible to select one or more diamines selected from bisaminophenoxydimethylpropane (each can be ortho, meta, para substituted). It is self-evident that these substituents R ₃ are selected in terms of electron affinity pKa. The diamine specified by R ₃ may be used alone or as a mixture of two kinds.

As the ester dianhydride represented by the above general formula (4), various ester dianhydrides can be used, but more specifically, from the viewpoint of the balance of various characteristics. R ₄ in the general formula (4) is

[0056]

[Chemical 21]

More preferably, the main component is an ester dianhydride which is a divalent organic group selected from The ester dianhydride specified by R ₁ may be used alone or as a mixture of two kinds.

As the tetracarboxylic dianhydride used in the present invention, essentially various tetracarboxylic dianhydrides can be used, but more specifically, from the balance of various characteristics, it is generally used. Formula (5) 22

[0059]

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(In the formula, R ₃ is

[0061]

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A tetravalent organic group represented by : ) It is possible to select one of the one or more selected from the tetracarboxylic dianhydride least one tetracarboxylic dianhydride selected from the. These monomers may be used alone or as a mixture of two or more kinds.

Examples of the organic solvent used in the polyamic acid production reaction include sulfoxide-based solvents such as diamityl sulfoxide and diethyl sulfoxide, N,
Formamide solvents such as N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N,
Examples thereof include acetamide-based solvents such as N-diethylacetamide. These can be used only in one kind of solvent or in a mixed solvent composed of two or more kinds. Also, a mixed solvent composed of these polar solvents and a non-solvent of polyamic acid can be used. As non-solvents for polyamic acid, acetone, methanol, ethanol,
Isopropanol, benzene, methyl cellosolve and the like can be mentioned.

The molar ratio of the diamine compound and the acid dianhydride is substantially equimolar, and the component ratio of the diamine compound and the acid dianhydride is the same as the molar ratio of the general formula (1) / (2). They may be added so that they are the same.

In the thus-obtained copolymer according to the present invention, a polyamic acid copolymer and a polyimide having both the repeating units of the block units represented by the general formulas (1) and (2) A copolymer and a polyisoimide copolymer can be obtained.

The molecular weight is not particularly limited, but in order to maintain the strength of the polyimide resin produced, the number average molecular weight is 50,000 or more, more preferably 80,000 or more, and particularly 1
It is preferably at least 0,000, more preferably at least 120,000. Note that the description regarding the molecular weight of the polyimide is an estimate based on measured values obtained by an indirect method. That is, in the present invention, the measured value of the molecular weight of polyamic acid is regarded as the molecular weight of polyimide.

The polyimide copolymer obtained as described above has a molar fraction [(1) /
(2)] is in the range of 50/50 to 99/1 and has excellent thermoplasticity, heat resistance, low-temperature adhesiveness, low water absorption and low dielectric properties. Further, the polyamic acid copolymer which is a precursor thereof and the polyisoimide copolymer which is a structural isomer exhibit the same characteristics as the polyimide copolymer. These are characterized by having excellent heat resistance, thermoplasticity, adhesiveness, low water absorption property, and low dielectric property. Specifically, since this copolymer has a clear glass transition temperature between 200 and 350 ° C., it can be heat-sealed at a relatively low temperature, and by laminating at a temperature close to the glass transition temperature. It can be adhered to various adherends such as polyimide film, copper foil, FPC and the like. In addition, it shows excellent low water absorption properties and can be used in distilled water at 20 ° C for 24 hours.
The water absorption rate under the condition of immersion for a period of time is 1% or less. Furthermore,
Shows excellent low dielectric properties, 1MH in Q meter method
The dielectric constant of z is 3 or less. Although the mechanism of manifestation of low water absorption property and low dielectric property is not clear, it is speculated that it may be because the ester group adjacent to the imide five-membered ring reduces the electron bias. Due to these excellent low water absorption properties and low dielectric properties, it can be suitably used as an electronic circuit component material to be used for high-density packaging applications in the future. Further, it has a high viscosity in order to exhibit sufficient mechanical strength.

In addition, these heat-fusible copolymers according to the present invention may be incorporated with a thermoplastic resin such as nylon, polyvinyl acetate, polyvinyl chloride, polytetrafluoroethylene, polymethyl methacrylate, a filler, or a glass. Fibers and the like may be blended to obtain a copolymer composition, which can further improve various properties such as mechanical strength and adhesiveness.

[0069]

The heat-fusible copolymer produced by using the above-mentioned diamine and acid dianhydride has a glass transition temperature of 200 ° C. to 350 ° C. and has a clear glass transition temperature. Can be heat-sealed, and by laminating at a temperature close to the glass transition temperature, it can be adhered to various adherends, for example, a polyimide film, a metal foil such as SUS or copper, or FPCTOU. Further, since it has a storage elastic modulus of 0.5 to 2.0 GPa or more at 240 ° C., so-called liquid sagging can be eliminated. When the storage elastic modulus is 0.5 GPa or less, it flows when the film is applied as an adhesive and the adhesive strength cannot be maintained. Moreover, at 2.0 GPa or more,
Poor adhesion when crimping, and cannot be bonded. Further, since it has a water absorption rate of 1% or less and a dielectric constant of 3 or less, it can be suitably used as a material for electronic circuit components which should be adapted to future high-density mounting applications.

As an example of the application of the novel polyimide polymer composition having heat fusion property according to the present invention obtained by the above-mentioned method, there is, for example, an adhesive for coverlay. That is, a film made of the polyimide polymer according to the present invention is provided between a non-thermoplastic polyimide film such as "Apical" series (registered trademark; polyimide film, manufactured by Kanegafuchi Chemical Industry Co., Ltd.) and a conductor layer of FPC. It suffices if they are sandwiched and pasted together and thermocompression bonded. Alternatively, the polyamic acid solution may be cast on a polyimide film to imidize it, and then the adhesive surface of this film and the conductor surface of the FPC may be bonded. Further, the imidized thermoplastic polyimide may be heated and melted and directly applied to the polyimide film, and then the FPC conductor surface may be adhered onto the polyimide film. In this way, the polyimide film and the conductor surface of the FPC can be easily bonded. Since the coverlay films produced by these methods are all made of polyimide and can be alkali-etched, they can be easily perforated after bonding with FPC. Therefore, after the above-mentioned bonding step, if the obtained laminate is subjected to alkali etching and perforation processing, a printed circuit board can be obtained more easily than in the conventional step.

In addition, the copolymer and the copolymer composition are used for insulating coating films such as superconducting wires and FPC,
It can be suitably used as a bonding sheet, cover coat ink, lead-on-chip, lead frame fixing tape, but it has mechanical strength, radiation resistance, chemical resistance,
The application is not particularly limited as long as it exhibits excellent properties in low-temperature characteristics, heat resistance, processability, adhesiveness, low water absorption, and dielectric characteristics.

To use as an adhesive layer for such electric / electronic equipment, a water absorption rate of 1% or less and 240 ° C.
Any thermoplastic resin having a storage elastic modulus of 0.5 GPa to 2.0 GPa and a glass transition temperature of 200 ° C. to 350 ° C. can be preferably used in any constitution, The novel copolymer having the heat-fusion property and the copolymer composition are not limited to those having the above-mentioned constitution. By having such characteristics, heat fusion at a low temperature becomes possible, and further, package cracks do not occur during molding due to moisture absorption, and high-speed arithmetic processing becomes possible.

The embodiments have been described above to clarify the usefulness of the novel polyimide polymer composition having the heat-fusible property according to the present invention, but the present invention is limited to these examples. However, the present invention is based on the knowledge of those skilled in the art without departing from the spirit of the invention, various improvements, changes,
It can be implemented in a modified mode.

[0075]

【Example】

Example 1 In a 500 ml three-necked flask (1) equipped with a stirrer and purged with nitrogen, 2,2-bis (4-hydroxyphenyl) propanedibenzoate-2,2,3,3-tetracarboxylic acid dian Hydride (hereinafter E
Called SDA. ) 42.92 g (74 mmol) and pyromellitic dianhydride 26.16 g (0.12 mmol)
Was weighed and collected. Dimethylformamide (hereinafter D
It is called MF. ) 470 g was added and stirred to obtain a uniform solution. 2,2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter referred to as BAPP) 82.1 g (0.2
mmol) and 20 g of DMF were added. After stirring for 30 minutes, a uniform and viscous solution was obtained. 3.48 g of ESDA (6 mm
ol) was dissolved in 35 g of DMF, and an acid solution prepared in advance was gradually added to the reaction solution while paying attention to thickening. After reaching the maximum viscosity, the addition of the acid solution was completed, and the mixture was allowed to stand for 1 hour with stirring to obtain a polyamic acid solution. When the viscosity was measured with a B-type viscometer, it showed 2600 poise.

100 g of this polyamic acid solution was measured, and 11.37 g of acetic anhydride and 11.18 g of isoquinoline.
And a chemical curing agent consisting of 11.95 g of DMF are added and cast-coated on a PET film using a comma meter to adjust the thickness to 25 μm.
After heating for 1 minute and peeling off the PET film,
The imidization was completed by heating at 200 ° C. for 25 minutes each. I
By R measurement, it was confirmed that the polyimide film had characteristic absorption at 1780 cm ^{− due} to an imide carbonyl group. The molar ratio of the general formula (1) and the general formula (2) is 7:
A polyamic acid solution of 3 was obtained. Table 1 shows the structure (molar ratio of the general formulas (1) and (2)) and the ultimate viscosity (poise) of the obtained polyamic acid solution. The viscosity was measured at 5 ° C.

[0078]

[Table 1]

The glass transition temperature (° C.), peel strength (MPa), elongation at break (%), tensile strength at break (MPa) storage modulus E ′ (GPa) at 240 ° C. of the obtained polyimide film were measured. It was measured. The glass transition temperature was measured by the TMA method, and the peel strength was 35 with a die bonder for a 100-micron lead made of 42 alloy.
9 using the sample adhered at 0 ° C., 10 MPa, 5 seconds
It was measured in the 0 degree peeling mode. Further, the seepage of the adhesive was visually evaluated under a 100-fold optical microscope. Regarding the water absorption rate, the weight change rate after immersion in pure water at 20 ° C. was measured according to ASTM D-570, and the storage elastic modulus was measured by viscoelasticity at a heating rate of 5 Hz and 5 ° C./min in a tensile mode. evaluated. The results are shown in Tables 1 and 2.

[0080]

[Table 2]

Next, the electrolytic copper foil of 35 μm and the obtained 25
A polyimide film of μm and a polyimide film of 50 μm “Apical 50 NPI (registered trademark; manufactured by Kaneka Kagaku Kogyo Co., Ltd.)” are overlaid, and the glass transition temperature is 50 ° C.
By pressing at a high temperature of 30 kg / cm ² for 10 minutes, a flexible copper clad plate (hereinafter referred to as FCCL) was obtained. The peel strength (MPa) was measured according to JISC6481 using the obtained FCCL. The results are shown in Table 2.

[Examples 2 to 6] Polyamic acid solutions were obtained by the same procedure as in Example 1 except that the monomer composition shown in Table 1 was used. Table 1 shows the structure and ultimate viscosity (poise) of each obtained polyamic acid solution. Then, using this polyamic acid solution, a polyimide film of 25 μm was obtained in the same manner as in Example 1, and further FCCL was obtained. Physical properties of the obtained polyimide film and FCCL were measured, and the results are shown in Tables 1 and 2.

[Comparative Example 1] A polyamic acid solution was obtained from ESDA and BAPP in the same manner as in Example 1. Also,
In the same manner as in Example 1, a 25 μm polyimide film was formed. The physical properties were measured, and the results are shown in Tables 1 and 2.

[0084]

[0085]

As described above, as shown in the specific embodiments,
The heat-fusible copolymer and the copolymer composition according to the present invention have excellent mechanical strength, excellent heat resistance, processability and adhesiveness, and low water absorption property. It has been clarified that it has both a low dielectric property and a high storage elastic modulus under heat. This is excellent in that it is possible to provide a material capable of simultaneously achieving the contradictory physical properties which cannot be achieved by conventional polyamide resin. Further, by using the heat-fusible copolymer composition according to the present invention as a die-bond-like adhesive, it is possible to reduce the occurrence of package cracks and solve the problem of adhesive seepage during die-bonding. It has become possible to provide materials. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain, for example, a novel copolymer having a heat fusion property capable of contributing to a reduction in processing time of a coverlay film in an adhesion step with FPC and a copolymer composition containing the same as a main component. . Therefore, the novel polyimide polymer composition having a heat-fusion property according to the present invention is, for example, a laminated film for insulation coating, FPC, cover film, coverlay film, bonding sheet, cover coat ink, lead-on-chip, lead. It can be suitably used as a frame fixing tape or the like.

[Brief description of drawings]

FIG. 1 is a graph showing a measurement chart of storage elastic modulus (E ^′ ).

Claims (6)

[Claims] 1. A water absorption rate of 1% or less and 0.5 to 240 ° C.
Has a storage elastic modulus of 2.0 GPa or more and 200 ° C.
Novel highly elastic polyimide resin composition having a glass transition temperature of ˜350 ° C. 2. The composition of the polyimide resin is represented by the general formula (1): And the general formula (2) (In the formula, R ₁ and R ₂ are divalent organic groups, R ₃ is a tetravalent organic group, and X is a chemical formula 3 It is a trivalent linking group selected from ) The novel high-elasticity polyimide resin composition according to claim 1. 3. R ₂ in the general formulas (1) and (2) is represented by the following formula: It is at least 1 sort (s) selected from the group of the bivalent organic group shown in Claim 3, The novel highly elastic polyimide resin composition of Claim 1 or Claim 2 characterized by the above-mentioned. 4. R ₁ in the general formula (1) is represented by the following formula: (In the formula, R ₄ is a divalent organic group) is at least one selected from the organic groups, and the novel highly elastic polyimide resin composition according to any one of claims 1 to 3. 5. R ₃ in the general formula (2) is represented by the following formula: The novel highly elastic polyimide resin composition according to any one of claims 1 to 4, which is at least one selected from the group of tetravalent organic groups shown in. 6. The R ₄ of R _{1 in} the general formula (1) is represented by the following formula: It is at least 1 sort (s) selected from the organic group shown in Claim 6. The novel highly elastic polyimide resin composition of Claim 1 thru | or 5 characterized by the above-mentioned.