JP2996858B2 - Heat resistant resin composition with excellent low temperature processability - 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. ing. (JP-A-5-10585
0, 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 temperatures. 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 a coupling agent, and have reached 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. 5 to 100 parts by weight of an epoxy compound having an epoxy group, 0.1 to 20 parts by weight of a compound having an active hydrogen group capable of reacting with the epoxy compound, and 0.1 to 50 parts by weight of a coupling agent as main components. It is a heat-resistant resin composition characterized by having.

In the polyimide resin of the present invention, the main acid component is 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride or 3,3', 4,4'-benzophenonetetracarboxylic dianhydride. is there. The main amine component is 2,2
One or two or more diamines selected from the group consisting of -bis (4- (4-aminophenoxy) phenyl) propane, 1,3-bis (3-aminophenoxy) benzene, and dimethylphenylenediamine; ).

[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)

Regarding the quantitative ratio, 3,3 ′, 4,4 ′
Amol of biphenyltetracarboxylic dianhydride and 3,
3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (bmol) is used as an acid component and 2,2-bis (4- (4-
C-aminophenoxy) phenyl) propane and 1,
One or two kinds of diamines selected from the group consisting of 3-bis (3-aminophenoxy) benzene and dimethylphenylenediamine and d moles of a siloxane compound represented by the general formula (1) as an amine component; a, b, c,
When the molar ratio of d and e is 0.5 ≦ a / (a + b) ≦ 0.8, 0.2
≦ b / (a + b) ≦ 0.5 and 0.05 ≦ e / (c + d
+ E) ≦ 0.5. One or two tetracarboxylic dianhydrides selected from the group consisting of 4,4'-oxydiphthalic dianhydride and ethylene glycol bistrimellitic dianhydride as other acid components within a range that does not impair the properties. They can be used together. As other amine components, 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 within a range that does not impair the properties thereof, Alternatively, they can be used in combination.

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 more preferably 0.900 ≦ r ≦ 1.06, and 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. Therefore, 95% or more, more preferably 98% or more. 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 exerted.

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, amino 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 component (D) coupling agent used in the heat-resistant resin composition of the present invention is compatible with the polyimide resin of the component (A) and the epoxy compound of the component (B).
It is preferable that the polyimide resin has good solubility in a solvent. For example, a silane-based coupling agent, a titanium-based or zircon-based coupling agent, and the like can be given. In particular, a silane coupling agent is preferable in terms of compatibility and solubility. The mixing ratio of the coupling agent is polyimide resin 1 of component (A).
The amount is 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight based on 00 parts by weight. If less than 0.1 parts by weight,
When the resin composition is used for bonding, the effect of improving the adhesion to the adherend is not exhibited. If the amount exceeds 50 parts by weight, the 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, the obtained polyimide solution is directly added to component (B) epoxy compound or other component (C),
By adding (D), a heat-resistant resin composition solution can be obtained. Alternatively, the polyimide solution may be poured into a poor solvent to reprecipitate and precipitate the polyimide resin, to remove unreacted monomers, to purify, and then to dry and 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.

[0023]

The polyimide resin of the present invention has an epoxy compound,
The heat-resistant resin composition to which a compound having an active hydrogen group capable of reacting with the epoxy compound and a coupling agent are added has an apparent glass transition temperature lower than the glass transition temperature of the polyimide resin, and low-temperature processability is improved. . 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 not yet clear, low-molecular-weight products obtained by the reaction of an epoxy compound with a compound having an active hydrogen group or a coupling agent are not suitable for polyimide resins having a specific structure. It acts as an agent and lowers the modulus of elasticity at a temperature lower than the glass transition temperature of the polyimide resin, thereby improving workability at low temperatures 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.

[0024]

【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,
Add 716 g of dehydrated and purified NMP, and stir vigorously for 10 minutes while flowing nitrogen gas. Next, 2,2-bis (4
-(4-aminophenoxy) phenyl) propane (BA
PP) 24.631 g (0.060 mol), 1,3-bis (3-aminophenoxy) benzene (APB)
236 g (0.165 mol), 57.753 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane (APPS, formula (2)) (average molecular weight 837, 0.06
9 mol), 1.491 g (0.006 mol) of 1,3-bis (3-aminopropyl) tetramethyldimethylsiloxane (APDS, k = 1 in the formula (2)) were added,
Heat the system to 60 ° C. and stir until uniform. After dissolving uniformly, the system was cooled to 5 ° C in an ice water bath,
4'-biphenyltetracarboxylic dianhydride (BPD
A) 52.960 g (0.180 mol), 3,3 ′,
38.668 g (0.120 mol) of 4,4'-benzophenonetetracarboxylic dianhydride (BTDA) was added over 15 minutes while keeping the powdery state, and then stirring was continued for 3 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 179 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 drying under reduced pressure at 80 ° C. for 12 hours to remove the solvent.
g (yield 91.5%) 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 the cyclic imide bond was recognized, but an absorption of 6.06 μm derived from the 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 133 ° C. and a tensile modulus of 170 kgf / m 2.
m ² , dimethylformamide (DMF), and 1,4-dioxane (1,4-DO) were confirmed to be well dissolved.

(Synthesis of polyimide resin PI-2) PI-2 was synthesized in the same manner as in the synthesis of polyimide resin PI-1.
I got P-Phenoxyaniline (PPA) was used as an end cap agent. The obtained polyimide resin has a glass transition temperature of 158 ° C. and a tensile modulus of 229 kgf / m.
It was confirmed that the compound dissolved well in m ² , dimethylformamide, and 1,4-dioxane. Table 1 shows the physical properties of the polyimide resins PI-1 and PI-2.

[0028]

[Table 1]

DPX in the monomer column represents 2,5-dimethyl-p-phenylenediamine. S in the column of solubility indicates that the compound is dissolved in the corresponding solvent. Glass transition temperature is D
It was determined by SC 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 330 g of DMF, and thoroughly stirred at room temperature to completely dissolve the polyimide. After uniformly dissolving, 50 g of a phenol novolak type epoxy compound (EOCN-1020, manufactured by Nippon Kayaku Co., Ltd.) was added, and the mixture was stirred at room temperature for 2 hours. After confirming that the silane coupling agent is uniformly dissolved, a silane coupling agent (trismethoxyethoxyvinylsilane, KBC1003, Shin-Etsu Chemical Co., Ltd.)
Was added and the mixture was stirred at room temperature for 1 hour. After confirming that it is dissolved uniformly, novolak resin (PR-536)
47, manufactured by Sumitomo Durez Co., Ltd.) was gradually added thereto 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 is applied to a mirror-polished stainless steel plate with a doctor blade, and the thickness is 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.

This 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
Room temperature after treatment at 5 ° C., 48 hours, 100% saturation)
And 180 ° peel strength at 240 ° C. (tensile 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.

[0034]

[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 is a biphenyl type epoxy compound epicoat YX-4000H, manufactured by Yuka Shell Epoxy Co., Ltd.
OCN-1020 indicates a phenol novolak type epoxy compound EOCN-1020, manufactured by Nippon Kayaku Co., Ltd., and Epicoat 828 indicates a bisphenol A type epoxy compound, manufactured by Yuka Shell Epoxy Co., Ltd., respectively. About the component (C) to be used, PR-175, 22193, 5364
7 is manufactured by Sumitomo Durez Corporation. The component (D) used is KBC
1003 (trismethoxyethoxyvinylsilane), K
BE1003 (triethoxyvinylsilane), KBM5
73 (N-phenyl-γ-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. was used.

(Comparative Examples 1 to 4) A resin composition containing only a polyimide resin or a resin composition obtained by adding one or two of components (B) to (D) was prepared. Next, an adhesive tape was produced in the same manner as in the example, and the adhesive strength with a 42 alloy plate was measured. Table 3 shows the results.

[0037]

[Table 3]

From the results shown in Tables 2 and 3, the adhesive strength of the resin films of Examples was slightly reduced even after moisture absorption. Further, although the adhesive strength at the time of heat after moisture absorption is reduced as compared with the normal state, it is possible to prevent the strength from being greatly reduced as compared with that of the comparative example.

The above examples show that the present invention can prevent the adhesive strength at the time of heat of moisture absorption from being greatly reduced, and can obtain a film adhesive excellent in 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-7-247408 (JP, A) JP-A-6-308502 (JP, A) JP-A-6-256472 (JP, A) JP-A-7-247 278412 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 79/00-79/08 C08G 73/00-73/26

Claims (3)

(57) [Claims] (1) The main acid component is 3,3 ′, 4,
4'-biphenyltetracarboxylic dianhydride and 3,
3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, wherein the main amine component is 2,2-bis (4-
(4-aminophenoxy) phenyl) propane, 1,3
-Bis (3-aminophenoxy) benzene and one or more diamines selected from the group of dimethylphenylenediamine and a diaminosiloxane compound represented by the general formula (1), which are soluble in an organic solvent. 100 parts by weight of a polyimide resin having a glass transition temperature of 350 ° C. or lower, (B) 5 to 100 parts by weight of an epoxy compound having at least two epoxy groups in one molecule, and (C) a reaction with the epoxy compound. 0.1 to 20 parts by weight of a compound having an active hydrogen group and (D) coupling agent 0.1 to
A heat-resistant resin composition having excellent low-temperature processability, comprising 50 parts by weight as a main component. 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) 2. Component (A) comprising a mole of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 3,3 ′,
4,4'-benzophenonetetracarboxylic dianhydride b
And an acid component, and is selected from c mol of 2,2-bis (4- (4-aminophenoxy) phenyl) propane, 1,3-bis (3-aminophenoxy) benzene and dimethylphenylenediamine. D or two kinds of diamines and e mole of a diaminosiloxane compound represented by the general formula (1) as an amine component;
When the molar ratio of d and e is 0.5 ≦ a / (a + b) ≦ 0.8, 0.2
≦ b / (a + b) ≦ 0.5 and 0.05 ≦ e / (c + d
2. The heat-resistant resin composition having excellent low-temperature processability according to claim 1, which is a polyimide resin obtained by reacting both components at a ratio of + e) .ltoreq.0.5 and imide ring-closing. 3. The heat-resistant resin composition according to claim 1, wherein the component (D) is a silane coupling agent.