JP2983827B2 - Resin composition with improved properties at high temperatures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant resin composition having excellent heat resistance, being soluble in an organic solvent, and having excellent moldability.

[0002]

2. Description of the Related Art Polyimide resin has high heat resistance, flame retardancy and excellent electrical insulation, so it is used as a film for a substrate of a flexible printed wiring board or a heat-resistant adhesive tape, and as a resin varnish, an interlayer insulating film of a semiconductor. Widely used for surface protection film. However, conventional polyimide resins have high hygroscopicity and excellent heat resistance, but are insoluble or infusible or have an extremely high melting point, and thus cannot be said to be materials which are easy to use in terms of workability. In addition, as a semiconductor mounting material, it is used for an interlayer insulating film, a surface protective film, and the like. For these, a polyimide resin precursor polyamic acid soluble in an organic solvent is applied to the semiconductor surface, and the solvent is removed by heat treatment. And is used after imidization. At this time, a high-temperature drying step of 300 ° C. or more is required to completely advance the imidization and to volatilize the amide-based solvent having a high boiling point.
For this reason, it is exposed to a high temperature, which causes thermal damage to other members to be used and deterioration of the element, thereby deteriorating the yield of the assembly process.
In addition, since the film has high hygroscopicity, there has been a problem that moisture absorbed at a high temperature evaporates at a stretch and causes swelling and cracks.

As a method for improving the above-mentioned drawbacks, there has been proposed a method of forming a film-like adhesive from a polyimide resin composition which is soluble in an organic solvent and has already been imidized, and thermocompression-bonds this to an adherend. (JP-A-5-105850,
112760, 112761). However, in such a case where the polyimide resin is used as a hot-melt type adhesive, if the glass transition temperature of the polyimide resin is high, a very high temperature is required for processing, and there is a great possibility that the adherend is thermally damaged. On the other hand, if the glass transition temperature of the polyimide resin is lowered to impart low temperature processability, there is a problem that the heat resistance characteristic of the polyimide resin cannot be fully utilized.

[0004]

The present invention has been made as a result of intensive studies to obtain a heat-resistant resin having excellent heat resistance and excellent moldability at low temperature. The inventors have found that the above problem can be solved by adding a compound having an active hydrogen group capable of reacting with the epoxy compound, and arrived at the present invention.

[0005]

The heat-resistant resin composition of the present invention comprises at least two or more resins per molecule per 100 parts by weight of a polyimide resin soluble in an organic solvent having a glass transition temperature of 350 ° C. or lower. A heat-resistant resin composition comprising, as main components, 5 to 100 parts by weight of an epoxy compound having an epoxy group and 0.1 to 20 parts by weight of a compound having an active hydrogen group capable of reacting with the epoxy compound. Things.

The main acid component of the polyimide resin of the present invention is 4,4'-oxydiphthalic dianhydride. 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride and ethylene glycol bistrimellitic dianhydride as other acid components One or two or more tetracarboxylic dianhydrides selected from the group consisting of the above may be used in combination in an amount not exceeding 50 mol% of the acid component. The main amine component is a diaminosiloxane compound represented by the general formula (1) and 1,3-bis (3-aminophenoxy)
It is benzene.

[0007]

Embedded image (Wherein, R ₁ and R _{2 are} divalent aliphatic or aromatic groups having 1 to 4 carbon atoms R ₃ , R ₄ , R ₅ and R _{6 are} monovalent aliphatic or aromatic groups k : Integer of 1 to 20)

Other amine components include, for example, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (2- (4-aminophenyl) propyl) benzene,
1,4-bis (4-aminophenoxy) benzene, 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 and the like can be used alone or in combination within a range not exceeding 50 mol% of the diamine component. .

Further, it is more preferable that the diaminosiloxane compound is used in an amount of 5 to 50 mol% of the total amount of the diamine component. If the total amount of the diamine components is less than 5 mol%, the solubility in an organic solvent is reduced, and if it exceeds 50 mol%, the glass transition temperature is remarkably lowered, and there is a problem in heat resistance. Specific examples of the siloxane compound represented by the general formula (1) include:
Α, ω-Bis (3-aminopropyl) polydimethylsiloxane (APPS) represented by the following general formula (2) is preferable. Particularly, when the value of k is in the range of 4 to 10, the glass transition temperature, adhesiveness, and heat resistance It is preferable from the viewpoint of properties. These siloxane compounds can be used alone or in combination of two or more. In particular, it is preferable to use a mixture of k = 1 and the above-mentioned k = 4 to 10 in applications where importance is attached to adhesiveness.

[0010]

Embedded image (Where k is an integer of 1 to 20)

The equivalent ratio between the acid component and the amine component in the polycondensation reaction is an important factor that determines the molecular weight of the resulting 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 acid component and the amine component is preferably 0.900 ≦ r ≦ 1.060, more preferably 0.975 ≦ r ≦ 1.025. Here, r = [equivalent number of all acid components] / [equivalent number of all amine components]. When r is less than 0.900, the molecular weight is low and the polymer becomes brittle, so that the adhesive strength is weak. If it exceeds 1.06, unreacted carboxylic acid may be decarbonated during heating to cause gas generation and foaming, which may be undesirable.

In the present invention, the addition of a dicarboxylic anhydride or a monoamine for controlling the molecular weight of the polyimide resin does not particularly hinder the addition of the dicarboxylic acid anhydride or monoamine as long as it is within the above-mentioned acid / amine molar ratio.

The reaction between the tetracarboxylic dianhydride and the diamine is carried out in a polar aprotic solvent by a known method. Aprotic polar solvents include N, N-dimethylformamide (DMF), N, N-dimethylacetamide (D
MAC), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), diglyme, cyclohexanone, 1,4-dioxane (1,4-DO) and the like. 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 carried out by dissolving the well-dried diamine component in the above-mentioned reaction solvent that has been dehydrated and purified, and adding thereto the ring-closing rate of 98%, more preferably 99% or more. The reaction is allowed to proceed by adding the anhydride.

The polyamic acid solution thus obtained is subsequently heated and dehydrated and cyclized in an organic solvent to give an 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 to form Dean-Stark (Dean-Stark).
k) Discharge out of the system using a device such as a pipe. Dichlorobenzene is known as an organic solvent that is not compatible with water, but the above-mentioned aromatic hydrocarbon is preferably used for electronics because a chlorine component may be mixed therein. Acetic anhydride, β-
It does not prevent the use of compounds such as picoline and pyridine.

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. Is preferably achieved.

The component (B) epoxy compound used in the heat-resistant resin composition of the present invention has at least two epoxy groups in one molecule and has compatibility with the component (A) polyimide resin. There is no particular limitation as long as the polyimide resin has good solubility in the solvent of the polyimide resin. For example, bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, phenol novolak type epoxy resin, biphenyl type epoxy compound and the like can be mentioned.

The amount ratio of the epoxy compound is 5 to 100 parts by weight with respect to 100 parts by weight of the component (A) polyimide resin.
In particular, it is preferably in the range of 10 to 70 parts by weight. 5
If the amount is less than 10 parts by weight, the effect of adding an uncured epoxy compound to lower the softening temperature of the resin composition and increase the low-temperature processability is unlikely to be exhibited. If the amount exceeds 100 parts by weight, the heat resistance of the polyimide resin is impaired, which is not preferable.

Further, the compound having an active hydrogen group capable of reacting with the component (C) epoxy compound used in the heat-resistant resin composition of the present invention is used in combination with the component (A) polyimide resin and the component (B) epoxy compound. Those having good compatibility and solubility of the polyimide resin in the solvent are preferred. For example, resol, novolak, amine compound and the like can be mentioned. The mixing ratio of the component (C) is 100% of the polyimide resin of the component (A).
The amount is 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight based on parts by weight. If the amount is less than 0.1 part by weight, the reaction rate of the uncured epoxy compound becomes extremely low, and the effect desired in the present invention does not appear. Further, it is difficult to control the flow of the resin when the elastic modulus of the resin at a high temperature is low. If the amount is more than 20 parts by weight, a gel is likely to be formed in a resin solution state, whereby processability is impaired and heat resistance of the resin composition is impaired, which is not preferable.

The heat-resistant resin composition of the present invention may contain a fine inorganic filler as long as its workability and heat resistance are not impaired.

In the present invention, a heat-resistant resin composition solution can be obtained by adding an epoxy compound or a compound having an active hydrogen group capable of reacting with the epoxy compound as it is to the obtained polyimide solution. Further, the polyimide solution may be poured into a poor solvent to reprecipitate the polyimide resin, remove unreacted monomers, purify, and dry to use as a solid polyimide resin. In applications that dislike the high-temperature process, or particularly in applications where impurities or foreign matter becomes a problem, it is preferable to dissolve again in an organic solvent to obtain a filtration and purification varnish. The solvent used at this time can be selected from solvents having a low boiling point in consideration of workability.

In the polyimide resin of the present invention, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone are used as ketone solvents, and 1,4-dioxane, tetrahydrofuran, and diglyme are used as ether solvents. It can be used as a low boiling point solvent. These solvents may be used alone or in combination of two or more. Alternatively, these low-boiling solvents may be added to a polyimide resin solution for use.

[0022]

The heat-resistant resin composition comprising the polyimide resin of the present invention and an epoxy compound and a compound having an active hydrogen group capable of reacting with the epoxy compound has an apparent glass transition temperature higher than the glass transition temperature of the polyimide resin. It decreases and the low-temperature workability improves. On the other hand, the adhesive strength at a temperature higher than the glass transition temperature is higher than that of the polyimide resin, and the physical properties at a high temperature such as no peeling even when subjected to a thermal shock such as IR reflow are improved. Although the detailed mechanism for this peculiar phenomenon is still unclear, the low molecular weight product of the reaction between the epoxy compound and the compound having an active hydrogen group acts as a plasticizer on the polyimide resin of a specific structure. It lowers the modulus of elasticity at a temperature lower than the glass transition temperature of the polyimide resin, thereby improving workability at a low temperature such as adhesiveness and workability. On the other hand, in the region higher than the glass transition temperature, it is considered that a three-dimensional network structure is formed by the applied heat, and the fluidity of the polyimide resin is reduced, and thus the heat resistance of the polyimide resin is maintained or improved. With the above mechanism, both low-temperature workability and high-temperature heat-reliability can be achieved. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0023]

【Example】

(Synthesis of polyimide resin PI-1) In a four-necked flask equipped with a dry nitrogen gas inlet tube, a cooler, a thermometer, and a stirrer,
674 g of dehydrated and purified NMP is added, and the mixture is vigorously stirred for 10 minutes while flowing nitrogen gas. Next, 1,3-bis (3
-Aminophenoxy) benzene (APB) 61.391
g (0.210 mol), 2,2-bis (4- (4-aminophenoxy) phenyl) propane (BAPP)
473 g (0.045 mol), 37.665 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane (APPS, formula (2)) (average molecular weight 837, 0.04
5 mol), heat the system to 60 ° C. and stir until uniform. After homogeneous dissolution, the system was cooled to 5 ° C. in an ice water bath and 4,4′-oxydiphthalic dianhydride (ODPA)
93.067 g (0.300 mol) in powder form 15
The mixture was added over a period of one minute and stirring was continued for three hours. 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 xylene was attached to the flask, and 168 g of xylene was added to the system. The system was heated to 175 ° C. instead of the oil bath, and the generated water was removed from the system. 4
After heating for an hour, 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,
The solvent was removed by vacuum drying at 80 ° C. for 12 hours to remove the solvent.
g (92.7% yield) of a solid resin was obtained. When an infrared absorption spectrum was measured by a KBr tablet method, an absorption of 5.6 μm derived from a cyclic imide bond was recognized, but an absorption of 6.06 μm derived from an amide bond could not be recognized.
It was confirmed that this resin was almost 100% imidized.

The polyimide resin thus obtained has a glass transition temperature of 151 ° C. and a tensile modulus of 211 kgf / m 2.
m ² , dimethylformamide (DMF), and 1,4-dioxane (1,4-DO) were confirmed to be well dissolved.

(Synthesis of polyimide resins PI-2 and PI-3) PI-2 and PI-3 were obtained in the same manner as in the synthesis of the polyimide resin PI-1. Table 1 shows the physical properties of the obtained polyimide resins PI-1, PI-2 and PI-3.
It was shown to.

[0027]

[Table 1]

BTDA and APDS in the monomer column are 3,
3 ′, 4,4′-benzophenonetetracarboxylic dianhydride and 1,3-bis (3-aminopropyl) tetramethyldisiloxane (k = 1 in the formula (2)) are respectively represented. S in the column of solubility indicates that the compound is dissolved in the corresponding solvent. The glass transition temperature was determined by DSC measurement. The tensile test was performed at room temperature at a tensile speed of 5 mm / min. Young's modulus was determined using a viscoelastic spectrometer.

Example 1 A glass flask was charged with 100 g of polyimide resin PI-1 and 355 g of DMF, and thoroughly stirred at room temperature to completely dissolve the polyimide. After uniformly dissolving, 40 g of a bisphenol A type epoxy compound (Epicoat 828, manufactured by Yuka Shell Epoxy) was added, and the mixture was stirred at room temperature for 2 hours. After that, it was confirmed that the resin was uniformly dissolved, and the resole resin (PR-50781,
5.0 g of Sumitomo Durez Co., Ltd.) was gradually added while stirring the system. Subsequently, the mixture was stirred for 2 hours to prepare a heat-resistant resin solution. This solution composition did not gel even when left at room temperature for 5 days, and remained in a uniform solution state.

The resin solution thus obtained was applied to a mirror-polished stainless steel plate with a doctor blade, and the thickness was 50 μm.
m was obtained. The drying temperature was a maximum of 195 ° C. and the drying time was 20 minutes. Table 2 shows the solubility, glass transition temperature, tensile properties, and Young's modulus.

The varnish was applied to one surface of a polyimide film (trade name: UPILEX SGA, thickness: 50 μm, manufactured by Ube Industries, Ltd.) using a reverse roll coater to obtain an adhesive tape having an adhesive layer thickness of 30 μm. The drying temperature was a maximum of 200 ° C. and the drying time was 15 minutes. This adhesive tape was thermocompression bonded to a 42 alloy plate to prepare a test piece (2
After thermocompression bonding at 50 ° C. for 2 seconds, the pressure was released, and annealing was performed at 250 ° C. for 30 seconds. The pressure applied to the bonded surface was 4 kgf / cm ² calculated from the gauge pressure and the bonded area. ), And the results of measuring the 180 degree peel strength with a tensile tester are shown in Table 2. The adhesive strength was normal and pressure cooker (12
The peel strength at room temperature after treatment at 5 ° C. for 48 hours at a saturation of 100% was measured (tension speed: 50 mm / min). In the fracture surface of the test piece, the adhesive resin layer was cohesively broken, and no foaming was observed.

Examples 2 to 4 Resin solutions were prepared in the same manner as in Example 1 with the formulations shown in Table 2 to obtain films and adhesive tapes. Table 2 shows the obtained evaluation results.

[0033]

[Table 2]

S in the column of solubility indicates that the compound is soluble in the corresponding solvent. The glass transition temperature was determined by DSC measurement. The tensile test was performed at room temperature at a tensile speed of 5 mm / min. About the component (B) epoxy compound used,
YX-4000H indicates biphenyl type epoxy compound Epicoat YX-4000H, manufactured by Yuka Shell Epoxy Co., Ltd., and EOCN-1020 indicates phenol novolak type epoxy compound EOCN-1020, manufactured by Nippon Kayaku Co., Ltd. About the component (C) used, P
R-50781, 175, 53647 are manufactured by Sumitomo Durez Corporation.

(Comparative Examples 1, 2, 3) Polyimide resin PI
-1, PI-2 and PI-3 alone were prepared, and the adhesive strength to a 42 alloy plate was measured in the same manner as in the Examples. The results are shown in Table 3.

[0036]

[Table 3]

Comparative Example 4 Polyimide Resin PI-1,1
The adhesive strength of an adhesive tape obtained from a resin prepared using only 00 g and Epicoat 828 and 20 g was measured in the same manner as in the example, and the results are shown in Table 3.

From the results shown in Tables 2 and 3, the adhesive strength of the resin film of the example was slightly reduced even after moisture absorption, but the adhesive strength of the polyimide resin film of the comparative example was lower than that of the normal state. After that, it has dropped significantly.

The above examples show that the present invention can provide a film adhesive having excellent heat resistance and moldability.

[0040]

According to the present invention, it is possible to provide a highly reliable film adhesive having both heat resistance and moldability. Since it is soluble in a low boiling point solvent, the residual solvent can be almost completely eliminated, and since it has already been imidized, a high temperature process for imidization is not required 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.

The method of using the resin composition of the present invention is not particularly limited. However, as a resin varnish in which all of the resin components are uniformly dissolved in an organic solvent, coating and dipping are performed by casting. The film can be used as an insulating material, an adhesive film, or the like that has both heat resistance and processability.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-7-224151 (JP, A) JP-A-5-140526 (JP, A) JP-A-5-339555 (JP, A) JP-A-5-339555 331284 (JP, A) JP-A-5-331425 (JP, A) JP-A-5-140524 (JP, A) JP-A-5-311147 (JP, A) JP-A-6-345964 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08L 79/08-79/08 C09J 179/08-179/08 C08G 73/00-73/26 C08G 59/00-59/72 CA ( STN) REGISTRY (STN)

Claims (2)

(57) [Claims] (A) A main acid component is 4,4′-oxydiphthalic dianhydride, and a main amine component is a diaminosiloxane compound represented by the general formula (1) and 1,3
100 parts by weight of a polyimide resin having a glass transition temperature of 350 ° C. or lower and soluble in an organic solvent comprising -bis (3-aminophenoxy) benzene, and (B) an epoxy having at least two epoxy groups per molecule. Compounds 5 to 10
A heat-resistant resin composition comprising, as main components, 0 parts by weight and (C) 0.1 to 20 parts by weight of a compound having an active hydrogen group capable of reacting with the epoxy compound. 2. The heat-resistant resin composition according to claim 1, wherein the component (A) is a polyimide resin containing the diaminosiloxane compound represented by the general formula (1) in an amount of 5 to 50 mol% of the total amount of the amine components. . Embedded image (Wherein, R ₁ and R _{2 are} divalent aliphatic or aromatic groups having 1 to 4 carbon atoms R ₃ , R ₄ , R ₅ and R _{6 are} monovalent aliphatic or aromatic groups k : Integer of 1 to 20)