JP3908326B2 - Aromatic oligomer and epoxy resin composition and cured product thereof - Google Patents

Description

【００２９】
【発明の効果】
本発明のエポキシ樹脂組成物は低吸湿性、高耐熱性、および異種材料との高密着性等に優れた硬化物を与え、電子部品の液状封止材として好適に使用することが可能である。
【図面の簡単な説明】
【図１】本発明芳香族オリゴマーのＧＰＣチャートである。
【図２】本発明芳香族オリゴマーの赤外吸収スペクトルである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aromatic oligomer useful as an epoxy resin modifier, and sealing of electric and electronic parts that give a cured product excellent in low moisture absorption, high heat resistance, and high adhesion to dissimilar materials, and circuit board The present invention relates to an epoxy resin composition useful as a material and the cured product thereof.
[0002]
[Prior art]
Conventionally, epoxy resins have been used in a wide range of industrial applications, but their required performance has become increasingly sophisticated in recent years. For example, there is a semiconductor sealing material in a typical field of a resin composition mainly composed of an epoxy resin, but as the integration degree of semiconductor elements is improved, the package size is becoming larger and thinner, and the mounting method is also increased. The transition to surface mounting is progressing, and the development of materials with excellent solder heat resistance is desired. Therefore, as a sealing material, in addition to reducing moisture absorption, improvement in adhesion and adhesion at the interface between different materials such as lead frames and chips is strongly demanded.
[0003]
In order to overcome these problems, epoxy resins having various new structures have been studied from the side of the epoxy resin that is the main agent. However, it has been difficult to achieve a balance of physical properties, such as a decrease in heat resistance due to low moisture absorption and a decrease in curability associated with improved adhesion, only by improving the main agent.
Therefore, an epoxy resin modifier has been studied from the above background. As an example, indene coumarone resin has been known for some time and has already been used for applications such as paints, rubbers, adhesives, etc., but it can maintain a balance of physical properties such as adhesion, heat resistance and moisture resistance. There wasn't. Japanese Patent Application Laid-Open No. 6-107905 shows that an indene resin having an increased indene content is applied to electronic materials, but it is not sufficient in terms of performance.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide an epoxy resin modifier, an epoxy resin composition, and a cured product thereof excellent in moldability and having excellent effects such as low moisture absorption, high heat resistance, and high adhesion to different materials. It is to provide.
[0005]
[Means for Solving the Problems]
That is, the present invention relates to an epoxy resin composition comprising an epoxy resin, a curing agent, and a modifier, and as a modifier component, 10 to 100% by weight of benzothiophene and a vinyl compound 90 to 0 copolymerizable with benzothiophene. An epoxy resin composition comprising 5 to 50 parts by weight of an aromatic oligomer having a softening point of 180 ° C. or less obtained by cationic polymerization of 5% by weight based on 100 parts by weight of an epoxy resin. Also, it is a cured epoxy resin obtained by curing it.
[0006]
The aromatic oligomer of the present invention contains a benzothiophene structure as a constituent component at 10% by weight or more, preferably the benzothiophene structure content is 20% by weight or more, more preferably 30% by weight or more. The upper limit of the content of the benzothiophene structure is 100% by weight. However, in the polymerization, benzothiophene alone has poor polymerizability, and it is difficult to achieve a high molecular weight, and there is a problem that the resin yield is lowered. Is preferably 80% by weight or less.
[0007]
In addition to the moisture resistance and adhesion produced when blended with an epoxy resin, which is the effect of the present invention, the excellent moldability is attributed to the good compatibility of the aromatic oligomer as a modifier with the epoxy resin. . That is, it greatly depends on the content of the benzothiophene structure, and the higher the ratio of the benzothiophene structure, the better from the viewpoint of the balance of physical properties. However, in some cases, a structural unit such as styrene may be contained from the viewpoint of fluidity and low viscosity.
[0008]
The molecular weight of the aromatic oligomer used in the present invention is usually in the range of 200 to 3000 in terms of number average molecular weight. The property is in the range of liquid to softening point at 180 ° C. at normal temperature, but usually the preferred softening point range is 60 to 130 ° C.
[0009]
The aromatic oligomer used in the present invention can be obtained by cationic polymerization of benzothiophene alone or a monomer containing benzothiophene. Monomers used for copolymerization include methylbenzothiophenes, indene, methylindenes, styrene, p-methylstyrenes, alkylstyrenes such as α-methylstyrene, vinylnaphthalene, vinylbiphenyl, acenaphthylene, acrylic acid, acrylic ester And monomers having an unsaturated bond such as methacrylic acid, methacrylic acid esters, maleic anhydride, fumaric acid, divinylbenzenes, and diisopropenylbenzene. Preferred are aromatic olefins such as methylbenzothiophenes, indene, methylindenes, styrene, and alkylstyrenes. These monomers can be used as a mixture, but benzothiophene, which is an essential component, needs to be contained in an amount of 10% by weight or more in the polymerization component. When synthesizing by cationic polymerization, alkyl traps such as phenol and cresols, dialkylphenols such as xylenol, naphthols, bisphenols such as bisphenol A and bisphenol F, or phenol novolacs, phenol aralkyl resins, etc. The polyfunctional phenol compound may be added. The amount of these phenol compounds added is usually 20% by weight or less. If it is more than this, the heat resistance and moisture resistance of the cured epoxy resin will be lowered.
[0010]
The aromatic oligomer used in the present invention is usually synthesized by cationic polymerization. The polymerization is usually performed in the presence of an acidic catalyst. The acid catalyst can be appropriately selected from known inorganic acids and organic acids. For example, mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, methane Examples thereof include organic acids such as sulfonic acid, Lewis acids such as zinc chloride, aluminum chloride, iron chloride, and boron trifluoride, and solid acids such as activated clay, silica alumina, and zeolite.
This polymerization is usually carried out at 10 to 250 ° C. for 1 to 20 hours. In the reaction, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, aromatic compounds such as benzene, toluene, chlorobenzene, dichlorobenzene, etc. may be used as a solvent. it can.
[0011]
The compounding amount of the aromatic oligomer used in the present invention as an epoxy resin composition is usually in the range of 5 to 50 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the epoxy resin. If it is less than this, the effect of improving low hygroscopicity and adhesion is small, and if it is more than this, there is a problem that the strength and heat resistance of the cured product are lowered.
[0012]
The epoxy resin used in the present invention is selected from those having two or more epoxy groups in one molecule. For example, divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, tetrabromobisphenol A, hydroquinone, resorcin, or tris- (4 -Hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, novolak resins such as phenol, cresol and naphthol, aralkyl resins such as phenol, cresol and naphthol Examples include glycidyl etherified compounds. These epoxy resins can be used alone or in combination of two or more.
[0013]
As the curing agent used in the resin composition of the present invention, any of those generally known as epoxy resin curing agents can be used, such as dicyandiamide, acid anhydrides, polyhydric phenols, aromatic and aliphatic amines. Etc.
[0014]
Specific examples of the acid anhydride curing agent include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl hymic anhydride, dodecynyl succinic anhydride, nadic anhydride And trimellitic anhydride.
[0015]
Examples of the polyhydric phenols include divalent phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4′-biphenol, 2,2′-biphenol, hydroquinone, resorcin, and naphthalenediol, or , Tris- (4-hydroxyphenyl) methane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, phenol novolak, o-cresol novolak, naphthol novolak, polyvinylphenol, Phenols, further phenols, naphthols, or bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcin, na There are polyhydric phenolic compounds synthesized by a condensing agent such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, p-xylylene glycol, etc., which are divalent phenols such as phthalenediol.
[0016]
Examples of amines include aromatic amines such as 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylsulfone, m-phenylenediamine, and p-xylylenediamine, ethylenediamine, There are aliphatic amines such as hexamethylenediamine, diethylenetriamine, and triethylenetetramine.
[0017]
In the resin composition of the present invention, one or two or more of these curing agents can be mixed and used.
[0018]
Furthermore, you may mix | blend suitably oligomers or high molecular compounds, such as polyester, polyamide, a polyimide, polyether, a polyurethane, a petroleum resin, and a phenoxy resin, in the composition of this invention.
[0019]
Moreover, additives, such as an inorganic filler, a pigment, a flame retardant, a thixotropic agent, a coupling agent, a fluidity improver, can be mix | blended with the resin composition of this invention. Examples of inorganic fillers include silica powder such as spherical or crushed fused silica and crystalline silica, alumina powder, glass powder, or mica, talc, calcium carbonate, alumina, hydrated alumina, and the like. Includes organic or inorganic extender pigments, scaly pigments, and the like. Examples of the thixotropic agent include silicon-based, castor oil-based, aliphatic amide wax, polyethylene oxide wax, and organic bentonite.
[0020]
Furthermore, conventionally well-known hardening accelerators can be used for the resin composition of this invention as needed. Examples include amines, imidazoles, organic phosphines, Lewis acids and the like. As addition amount, it is the range of 0.2-5 weight part normally with respect to 100 weight part of epoxy resins. Further, if necessary, the resin composition of the present invention includes a release agent such as carnauba wax and OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, and trioxide. Flame retardants such as antimony, low stress agents such as silicone oil, lubricants such as calcium stearate, etc. can be used.
[0021]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
(Synthesis example of aromatic oligomer)
Example 1
42.9 g of benzothiophene and 37.1 g of indene were dissolved in 120 g of toluene and heated to 110 ° C. Then, boron trifluoride dimethyl ether complex 0.8g was dripped over 15 minutes, stirring. After dropping, the reaction was further continued for 3 hours. Thereafter, 2.4 g of calcium hydroxide was added for neutralization. After removing the neutralized salt and excess calcium hydroxide by filtration, toluene and unreacted monomer were removed by distillation under reduced pressure to obtain 35 g of an aromatic oligomer. The obtained oligomer had a softening point of 94 ° C. and a melt viscosity at 150 ° C. of 1.5 poise. The GPC chart of the obtained oligomer is shown in FIG. 1, and the infrared absorption spectrum is shown in FIG. GPC measurement conditions are as follows: Device: HLC-82A (manufactured by Tosoh Corporation), column: TSK-GEL1000 x 1, TSK-GEL2000 x 3 and TSK-GEL3000 x 1 (both are Tosoh Corporation) Manufactured), solvent: tetrahydrofuran, flow rate: 1 ml / min, temperature: 38 ° C., detector: RI.
[0022]
Example 2
Using 22.3 g of benzothiophene and 57.7 g of indene, the reaction was conducted in the same manner as in Example 1 to obtain 52 g of an aromatic oligomer. The resulting oligomer had a softening point of 90 ° C. and a melt viscosity at 150 ° C. of 4 poise.
[0023]
Example 3
The reaction was conducted in the same manner as in Example 1 using 55 g of benzothiophene, 20 g of styrene, and 5 g of phenol to obtain 42 g of an aromatic oligomer. The resulting oligomer had a softening point of 84 ° C. and a melt viscosity at 150 ° C. of 1.2 poise.
[0024]
Example 4
Using 80 g of benzothiophene, the reaction was carried out in the same manner as in Example 1 to obtain 24 g of an aromatic oligomer. The obtained oligomer was liquid at room temperature, and the melt viscosity at 150 ° C. was 0.2 poise or less.
[0025]
Examples 5-8
Aromatic oligomer obtained in Examples 1, 2, 3, and 4 as a modifier, bisphenol A type epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) as an epoxy resin, and phenol novolak (Tamanol 758, as a curing agent) Arakawa Chemical Co., Ltd.), using triphenylphosphine as a curing accelerator and blending each component in the proportions shown in Table 1, followed by roll kneading to obtain an epoxy resin composition. Using this epoxy resin composition, a cured product was obtained by heat curing at 150 ° C. for 3 minutes and further at 175 ° C. for 12 hours, and then subjected to various physical property measurements. The glass transition point was calculated | required with the temperature increase rate of 7 degree-C / min using the thermomechanical measuring apparatus. After heat-curing under the above conditions, measurement was performed with a tensile tester under a pulling speed of 0.5 mm / min. The water absorption was 133 ° C., 3 atm, 96 hours, and the weight change after moisture absorption. Peel strength is determined by placing a molding frame (100 mm x 100 mm x 3 mm) on polyimide or copper foil, and then using an compression molding machine to cure the epoxy resin composition at 130 ° C for 7 minutes and further at 175 ° C for 12 hours. Then, after curing by heating to obtain a cured product, it was measured according to JIS-K6481. Note that Upilex S (manufactured by Ube Industries) was used as the polyimide, and 3EC-III (35 μm, surface roughness 7-8, Mitsui Metals) was used as the copper foil. The results are shown in Table 1.
[0026]
Comparative Example 1
Each component was mix | blended in the ratio shown in Table 1 without adding a modifier, and after mixing and heat-curing similarly to Examples 5-8 and obtaining hardened | cured material, various physical property measurements were performed. The results are shown in Table 1.
[0027]
Comparative Example 2
Normal indene coumarone resin (N-100S, manufactured by Nippon Steel Chemical Co., Ltd .; softening point 98 ° C., melt viscosity 8 poise (150 ° C.)) was used as a modifier, and each component was mixed in the proportions shown in Table 1. After mixing and mixing and heat-curing in the same manner as in Examples 5 to 8 to obtain a cured product, various physical properties were measured. The results are shown in Table 1.
[0028]
[Table 1]

[0029]
【The invention's effect】
The epoxy resin composition of the present invention gives a cured product excellent in low hygroscopicity, high heat resistance, and high adhesion to dissimilar materials, and can be suitably used as a liquid sealing material for electronic parts. .
[Brief description of the drawings]
FIG. 1 is a GPC chart of an aromatic oligomer of the present invention.
FIG. 2 is an infrared absorption spectrum of the aromatic oligomer of the present invention.

Claims (2)

In an epoxy resin composition comprising an epoxy resin, a curing agent and a modifier , cationic polymerization of 10 to 100% by weight of benzothiophene and 90 to 0% by weight of a vinyl compound copolymerizable with benzothiophene as modifier components An epoxy resin composition obtained by blending 5 to 50 parts by weight of an aromatic oligomer having a softening point of 180 ° C. or less obtained with respect to 100 parts by weight of an epoxy resin. An epoxy resin cured product obtained by curing the epoxy resin composition according to claim 1 .

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