JP2003002951A - Cured thin-film of liquid epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide cured thin-film suitable as an encapsulant for a surface packaging semiconductor device and an encapsulant for a chip light-emitting diode(LED) or a photoconductor. SOLUTION: This thin-film consists essentially of (A) an epoxy resin, (B) a curing agent (C) a curing accelerator and (D) an inorganic filler. The major curing agent (B) is methylnorbornane-2,3-dicarboxylic anhydride and the contents of succinic anhydride in the curing agent (B) is <=0.4 wt.%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thin film cured product of a liquid epoxy resin composition, and in particular to BGA (ball grid array), CSP (chip size package),
Sealing material for surface-mount type semiconductor devices such as COG (chip on glass), COB (chip on board) or MCM (multi-chip module), and chip type LEDs or optical semiconductors A thin film cured product suitable for a material.

[0002]

2. Description of the Related Art In recent years, as typified by the development of portable electronic devices such as mobile phones, digital cameras, and notebook personal computers, electronic parts have a tendency toward higher density and higher integration. , LEDs, optical semiconductors, and the like tend to be smaller and thinner. Regarding semiconductor packages, as a method that can be highly integrated without taking up the mounting area,
Methods such as BGA (ball grid array), CSP (chip size package), COG (chip on glass), COB (chip on board) or MCM (multi-chip module) have been developed. ing. Further, chip types capable of surface mounting have also been developed for LEDs and optical semiconductors.

A liquid epoxy resin is used as a sealing material for these elements because of its good workability and excellent electrical properties, mechanical properties, heat resistance, adhesiveness, water resistance and solvent resistance of the cured product. used.

As a curing agent for such a liquid epoxy resin, a liquid acid anhydride has a low viscosity, is excellent in workability, can be blended with a large amount of filler, and is excellent in electrical properties, mechanical properties and heat resistance. Is frequently used and is appropriately selected according to the application. For example, acid anhydride curing agents for epoxy resin encapsulants for semiconductor packages include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylnorbornene-
2,3-dicarboxylic acid anhydride, trialkyltetrahydrophthalic anhydride, and mixtures thereof are used. Further, regarding chip-type LEDs and optical semiconductors, since a cured product is required to be transparent, acid anhydrides having no double bond such as methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and mixtures thereof. Is used.

The encapsulating material is usually applied to a thin film of about 2 mm or less by a dispenser method, atmospheric pressure screen printing or vacuum screen printing method after the element is bare-chip mounted on the substrate, potting or semiconductor element and substrate. After being impregnated into the gap of No. 1 and temporarily stored in a rack or the like until a fixed quantity is reached, it is put into a curing oven and cured.

However, when a liquid epoxy resin composition using a conventional acid anhydride curing agent is cured in a thin film in such a process, problems such as a decrease in glass transition temperature (Tg) of the cured product and occurrence of cracks occur. there were.

Further, the influence of moisture absorption of the liquid epoxy resin composition in the coating process and the temporary storage process of the coated product cannot be ignored, and the physical properties of the cured product deteriorate. That is, a liquid epoxy resin composition using a conventional acid anhydride curing agent has a high moisture absorption rate, and free acid in the epoxy resin composition increases due to moisture absorption. There is a problem that the moisture resistance decreases during the pressure cooker test, and that the moisture resistance decreases due to rapid hydrolysis, etc.

Further, although lead-free solder tends to be used due to environmental problems, the lead-free solder has a higher reflow temperature than the conventional type, and the sealing material is required to have high heat resistance, that is, high Tg. In order to obtain a high Tg in the epoxy resin composition using the acid anhydride curing agent, it is necessary to mix the polyfunctional solid epoxy resin, so that the viscosity of the epoxy resin composition increases and the workability is impaired. I was holding.

Further, in recent years, in order to shorten the sealing work time, a method of curing at a high temperature of 200 ° C. or higher under a curing condition of several minutes or less has been devised, but in the case of the conventional acid anhydride, bubbles are generated in the cured product. There was a problem that occurs.

Therefore, in order to obtain a highly accurate and highly reliable product, these epoxy resin encapsulating materials have a low moisture absorption, a low viscosity, a low curing shrinkage rate, a high insulating property, and a high temperature in a short time. Bubbles do not occur in the cured product even when cured, there is little deterioration in physical properties when cured into a thin film, even when cured after being exposed to a hygroscopic environment after being applied or potted,
There is a demand for a thin film cured product of an epoxy resin composition having excellent physical properties in a well-balanced manner, such as a cured product having a high Tg and low moisture absorption.

On the other hand, the present inventors have found that methylnorbornane-2,3-dicarboxylic anhydride or methylnorbornane-2,3-dicarboxylic anhydride and norbornane-2,3-in which the amount of impurities is below a specific amount. It has been found that when a mixture of dicarboxylic acid anhydrides is used as a curing agent for an epoxy resin composition, the resin composition has high insulation and is useful as an insulating encapsulant, and has a small curing shrinkage ratio (JP Two
001-114868).

[0012]

DISCLOSURE OF THE INVENTION According to the present invention, when applied as a thin film, the moisture absorption rate is low, the curing shrinkage rate is low, the insulation of the cured product is high, and the Tg of the cured product is lowered even when cured by a thin film. Even if it is cured at a high temperature of 200 ° C. or higher for a short time, a uniform cured product without bubbles can be obtained, and even if it is exposed to a hygroscopic environment after being coated or potted with a thin film, the cured product has a high Tg, (EN) It is intended to provide a thin film cured product of a low-viscosity liquid epoxy resin composition suitable for surface mounting encapsulation containing an acid anhydride curing agent, which has a low moisture absorption rate of the cured product.

[0013]

Means for Solving the Problems As a result of further study to achieve the above-mentioned problems, the present inventors have found that
Methyl norbornane containing less than a specified amount of impurities
2,3-dicarboxylic anhydride or methylnorbornane-
2,3-Dicarboxylic anhydride and norbornane-2,3-
When an epoxy resin composition using a mixture of dicarboxylic acid anhydrides as a curing agent is cured with a thin film of 2 mm or less, a cured product has a low Tg decrease, and a thin Tc cured product having a high Tg is obtained. Low moisture absorption rate of objects 2
Even when cured after being exposed to a hygroscopic environment in the process of applying to a thin film of mm or less, the cured product has a small Tg decrease and excellent moisture resistance. Furthermore, even when cured at a high temperature of 200 ° C or more, little gas is generated and bubbles It was found that a uniform cured product having no cracking was obtained, and the present invention was completed based on such findings.

That is, the present invention provides the following inventions.

1. (A) epoxy resin, (B) curing agent,
(C) A thin film cured product of a liquid epoxy resin composition containing a curing accelerator as an essential component, wherein the main component of the (B) curing agent is methylnorbornane-2,3-dicarboxylic acid anhydride, (B) A thin film cured product of a liquid epoxy resin, characterized in that the succinic anhydride content in the curing agent is 0.4% by weight or less.

2. (A) epoxy resin, (B) curing agent,
A thin film cured product of a liquid epoxy resin composition comprising (C) a curing accelerator and (D) an inorganic filler as essential components,
The main component of the curing agent is methylnorbornane-2,3-dicarboxylic acid anhydride, and (B) the succinic anhydride content in the curing agent is 0.4% by weight or less. Cured product.

3. (B) The curing agent is methylnorbornane-2,3-dicarboxylic acid anhydride and norbornane-2,3
-The thin film cured product according to the above item 1 or 2, which comprises a dicarboxylic acid anhydride.

4. The thin film cured product according to any one of the above items 1 to 3, wherein the thin film cured product has a thickness of 2 mm or less.

5. The thin film cured product according to any one of items 1 to 4, wherein the liquid epoxy resin composition is applied or potted to a thickness of 2 mm or less and then cured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The epoxy resin (A) according to the present invention is preferably a liquid epoxy resin containing two or more epoxy groups in the molecule. For example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol AD diglycidyl ether, naphthalene diol diglycidyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, vinylcyclohexene diepoxide, etc. Alicyclic epoxy resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, bisphenol A ethylene oxide adduct diglycidyl ether, bisphenol A
Diglycidyl ether of propylene oxide adduct,
Examples thereof include polyglycidyl ester of polybasic acid such as cyclohexanedimethanol diglycidyl ether, polyglycidyl ether of polyhydric alcohol, and diglycidyl ether of hexahydrophthalic anhydride. These epoxy resins may be used alone or in admixture of two or more.

Among these, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, naphthalene diol diglycidyl ether, 3,4
-Epoxycyclohexylmethyl-3 ', 4'-cyclohexanecarboxylate or hydrogenated bisphenol A
It is preferable to use diglycidyl ether alone or in combination of two or more in order to obtain a low-viscosity epoxy resin composition.

When used as a sealing material for a semiconductor element, the low chlorine type epoxy having a total chlorine content of 1000 ppm or less and a hydrolyzable chlorine content of 400 ppm or less is used in order to prevent wiring migration. It is preferable to use a resin. Furthermore, since a large amount of inorganic fillers can be blended in this application, lower viscosity epoxy resins are required, so high purity products obtained by cutting high molecular weight products from these epoxy resins by molecular distillation etc. Preference is given to using.

Furthermore, UV resistance of blue LED, white LED, etc.
For applications requiring properties, use epoxy resin having no aromatic ring such as 3,4-epoxycyclohexylmethyl-3 ', 4'-cyclohexanecarboxylate or hydrogenated bisphenol A diglycidyl ether as a main component. Is preferred.

If necessary, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, hydroquinone type epoxy resin,
Naphthalene skeleton type epoxy resin, tetraphenylolethane type epoxy resin, DPP type epoxy resin, trishydroxyphenylmethane type epoxy resin, dicyclopentadiene phenol type epoxy resin, solid epoxy resin at room temperature, and butyl glycidyl ether Diluents such as glycidyl ether having one epoxy group such as alkyl glycidyl ether such as lauryl glycidyl ether, phenyl glycidyl ether and cresyl glycidyl ether can be used together. These epoxy resins or diluents that are solid at room temperature can be used alone or in admixture of two or more.

The main component of the curing agent (B) according to the present invention is methylnorbornane-2,3-dicarboxylic acid anhydride (hereinafter abbreviated as "HMeNA"). HMeNA is
Obtained by hydrogenating methylnorbornene-2,3-dicarboxylic anhydride. (B) The curing agent is HMe
It is preferable that NA is contained in an amount of 70% by weight or more.

HMeNA has exo and endo stereoisomers. It is preferable to use the exo form as an essential component from the viewpoint that it becomes liquefied at room temperature when the abundance ratio of the exo form of HMeNA increases, so that it can be easily handled as an epoxy resin curing agent. Therefore, it is desirable that at least a part of the HMeNA endo form is isomerized into an exo form. The isomerization of the endo form is described in, for example, Japanese Patent Laid-Open No.
As described in JP-A-25207, a part or all of methylnorbornene-2,3-dicarboxylic acid anhydride is subjected to methylenenorbornane-2, in the presence of an acid catalyst.
This can be achieved by isomerizing to 3-dicarboxylic acid anhydride and then hydrogenating. The existence ratio of the exo form in HMeNA is preferably 40% by weight or more, more preferably 50% by weight or more. If it is less than 40% by weight, the freezing point increases, which is not preferable.

The curing agent (B) according to the present invention is HMeNA.
In addition, norbornane-2,3-dicarboxylic acid anhydride (hereinafter abbreviated as "HNA") may be contained up to 30% by weight in 100% by weight of the curing agent (B). Although HNAs also have endo and exo forms, the proportion of exo forms in HNA is preferably 30% by weight or more, and more preferably 40% by weight or more. If it is less than 30% by weight, the freezing point increases, which is not preferable. HNA can be obtained by hydrogenating norbornene-2,3-dicarboxylic acid anhydride prepared by Diels-Alder reaction of cyclopentadiene and maleic anhydride, but norbornene-2,3-norbornene-2,3-synthesized by Diels-Alder reaction is usually used. The dicarboxylic acid anhydride is 95% by weight or more in the endo form, so by heating to 150 ° C. or higher to thermally isomerize the exo form to 30% by weight or more and then performing the hydrogenation reaction, 30% by weight or more of the exo form is obtained. H
NA can be obtained.

The mixture of HMeNA and HNA may be prepared by mixing separately prepared HMeNA and HNA,
In addition, methyl norbornene-2, which is a raw material of HMeNA,
It can also be obtained by mixing 3-dicarboxylic acid anhydride and norbornene-2,3-dicarboxylic acid anhydride, which is a raw material of HNA, and subjecting this mixture to isomerization and hydrogenation as in the case of obtaining HMeNA. .

As described above, methylnorbornene-2,3-
HMeNA, HNA or a mixture thereof obtained by isomerizing and hydrogenating dicarboxylic acid anhydride, norbornene-2,3-dicarboxylic acid anhydride or a mixture thereof may be:
Succinic anhydride is contained as an unavoidable impurity. This is because the isomerization reaction is carried out in the presence of an acid catalyst at a high temperature of about 180 ° C., so that it is isomerized while dissociating into maleic anhydride and methylcyclopentadiene (cyclopentadiene in the case of HNA), and part of maleic acid is removed. Remains as an anhydride,
This is because this is hydrogenated to form succinic anhydride. The content of succinic anhydride in the curing agent (B) according to the present invention is 0.4% by weight or less, preferably 0.2% by weight or less, out of 100% by weight of the curing agent (B). Impurity succinic anhydride has low solubility, and when it is present in an amount of more than 0.4% by weight, precipitation becomes remarkable and a procedure for re-dissolving is required, resulting in poor workability. Further, depending on the type of curing accelerator, there is a problem that the cured product is colored, which is not desirable.

The amount of succinic anhydride contained in the (B) curing agent can be reduced by a method such as vacuum distillation of HMeNA, HNA or a mixture thereof.
For example, at 138 ° C and 0.27 kPa, the initial distillation is 5 to 1
The succinic anhydride was reduced to 0%, and the rest was distilled under the condition of 173 ° C. and 0.27 kPa to give 0.2% of succinic anhydride.
It can be up to wt%.

The curing agent (B) according to the present invention is HMeNA.
And HNA, methyltetrahydrophthalic anhydride,
The effect of the present invention is not impaired by using conventionally known acid anhydride curing agents such as methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylnorbornene-2,3-dicarboxylic anhydride, and trialkyltetrahydrophthalic anhydride. HMeNA alone, or may be included in the range,
Those comprising a mixture of HMeNA and HNA are preferred, and those comprising a mixture of HMeNA and HNA are particularly preferred.

The (B) curing agent according to the present invention is preferably used in an amount corresponding to 0.6 to 1.4 equivalents, more preferably 0. It is 7 to 1.2 equivalents. If the compounding amount is less than 0.6 equivalents or exceeds 1.4 equivalents, the strength, hardness, moisture resistance and transparency after curing are deteriorated, which is not preferable.

As the (C) curing accelerator according to the present invention, a usual epoxy resin curing accelerator can be used. For example, tertiary amines such as benzyldimethylamine, tris (dimethylaminomethyl) phenol, dimethylcyclohexylamine, 1-cyanoethyl-2-ethyl-4-
Imidazoles such as methylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, triphenylphosphine, organic phosphorus compounds such as triphenylphosphite, tetraphenylphosphonium bromide, tetra-n- Quaternary phosphonium salts such as butylphosphonium bromide, diazabicycloalkenes such as 1,8-diazabicyclo (5,4,0) undecene-7 and organic acid salts thereof, zinc octylate, tin octylate and aluminum acetylacetone complex And the like, quaternary ammonium salts such as tetraethylammonium bromide and tetrabutylammonium bromide, boron compounds such as boron trifluoride and triphenylborate, and metal halides such as zinc chloride and stannic chloride. . Furthermore, a high melting point imidazole compound,
High melting point dispersion type latent accelerators such as amine addition type accelerators in which dicyandiamide and amine are added to epoxy resin, etc., Microcapsule type latent accelerators in which the surface of imidazole type, phosphorus type and phosphine type accelerators is coated with a polymer. Also, latent curing accelerators typified by high temperature dissociation type thermal cationic polymerization type latent curing accelerators such as amine salt type latent curing accelerators, Lewis acid salts and Bronsted acid salts can be used. . These curing accelerators can be used alone or in admixture of two or more.

Among these curing accelerators, imidazoles, quaternary phosphonium salts, and diazabicycloalkenes are preferable because a cured product having a high Tg can be obtained. For applications requiring transparency of cured products such as chip type LEDs and optical semiconductors, quaternary phosphonium salts, diazabicycloalkenes, organometallic compounds, quaternary ammonium salts are cured products with good transparency. Is preferable in that
Further, when used as a sealing material for a semiconductor element such as BGA, CSP, COG, COB, or MCM, it is required to be one liquid, and therefore it is preferable to use the latent curing accelerator described above.

The amount of the (C) curing accelerator compounded is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 6 parts by weight, based on 100 parts by weight of the (A) epoxy resin. . If the compounding amount of the curing accelerator (C) is less than 0.1 part by weight, the curing rate will be reduced, and if it exceeds 10% by weight, the hue will be deteriorated and the mechanical strength will be reduced, such being undesirable.

If necessary, the inorganic resin (D) may be added to the epoxy resin composition of the cured thin film of the present invention. Epoxy resin compositions containing no inorganic filler are preferred for applications requiring transparency such as LEDs and optical semiconductor encapsulants, while epoxy resin compositions containing inorganic filler are suitable for semiconductor encapsulating materials. Suitable for applications that require internal stress.

As the inorganic filler (D), either a particulate filler or a fibrous filler can be used. As the particulate filler, for example, crystalline silica, fused silica, alumina, talc, calcium carbonate, silicon nitride,
Aluminum hydroxide, magnesium hydroxide, kaolin,
Clay, dolomide, zinc oxide, mica powder, silicon carbide,
Examples thereof include glass powder, carbon, graphite, barium sulfate, titanium dioxide and boron nitride. Further, as the fibrous filler, for example, wollastonite, potassium titanate whiskers, glass fibers, alumina fibers, silicon carbide fibers, boron fibers, carbon fibers,
Examples include aramid fiber, phenol fiber, and metal whiskers. These inorganic fillers can be used alone or in combination of two or more. Further, as these inorganic fillers, those treated with a coupling agent or a surface treatment agent may be used. Of these, crushed or spherical fused silica is preferable because it is necessary to lower the linear expansion coefficient and internal stress when used as a sealing material for semiconductor elements, and depending on the application, low α-ray type Is preferably used.

The compounding amount of the inorganic filler (D) is 10 in total of (A) epoxy resin, (B) curing agent, and (C) curing accelerator.
100 to 900 parts by weight is preferable with respect to 0 parts by weight. If the blending amount exceeds 900 parts by weight, the viscosity increases remarkably, and casting or coating work by a dispenser or screen printing becomes difficult. If it is less than 100 parts by weight, the effect of lowering the curing shrinkage rate that can be expected by blending the inorganic filler is low, and particularly when used as a sealing material for semiconductor elements, problems such as warpage due to internal stress generation and interfacial peeling are not preferable.

The average particle size of the inorganic filler (D) is from 0.1 to 0.1
100 μm is preferable, and more preferably 0.5 to 80 μm.
m. When the average particle size is less than 0.1 μm, the viscosity of the epoxy resin composition becomes high, and when it exceeds 100 μm, there is a problem that mechanical strength is lowered and sedimentation occurs to deteriorate workability, which is not preferable. In order to keep the viscosity of the liquid epoxy resin composition low, it is preferable to use spherical inorganic fillers, and it is also effective to mix and use two or more fillers having different average particle diameters.

In the liquid epoxy resin composition according to the present invention, if necessary, an aliphatic polyol such as ethylene glycol and propylene glycol, an aliphatic or aromatic carboxylic acid compound, a carbon dioxide gas generation inhibitor such as a phenol compound, and a poly Flexibility-imparting agents such as alkylene glycol, antioxidants, plasticizers, lubricants, coupling agents such as silanes,
Surface treatment agent for inorganic filler, flame retardant, antistatic agent, colorant, antistatic agent, leveling agent, ion trap agent, slidability improving agent, various rubbers, impact resistance improving agent for organic polymer beads, etc. Additives such as denaturing agents, surfactants, surface tension lowering agents, defoaming agents, anti-settling agents, light diffusing agents, ultraviolet absorbers, antioxidants, release agents, fluorescent agents, conductive fillers, etc. can do.

The method for producing the liquid epoxy resin composition according to the present invention is not particularly limited, and the (A) epoxy resin,
(B) curing agent, (C) curing accelerator, and (D) if necessary
Incorporating inorganic fillers and other additives, rolls, mixers,
It can be produced by a conventionally known method such as mixing with a kneader or the like. Further, (A) an epoxy resin and, if necessary, (D) an epoxy resin liquid containing an inorganic filler as a main component,
Two liquids of (B) a curing agent and (C) a curing agent liquid containing a curing accelerator as a main component are prepared, and the epoxy resin liquid and the curing agent liquid are mixed before use to produce a liquid epoxy resin composition. Alternatively, (A) epoxy resin, (B) curing agent,
The liquid epoxy resin composition may be produced in the form of one liquid by mixing (C) the curing accelerator, and optionally (D) the inorganic filler and other additives. In the case of the one-liquid form, it is preferable to use the above-mentioned latent curing accelerator as the (C) curing accelerator for the purpose of improving the storage stability of the liquid epoxy resin composition.

The thin film cured product of the present invention is a cured product of the liquid epoxy resin composition having a thickness of 2 mm or less. The thin film cured product of the present invention can be obtained by applying the liquid epoxy resin composition in a thickness of 2 mm or less, and in the case of potting or an underfill agent, impregnating it between the semiconductor element and the substrate and then curing.

The method of coating, potting or impregnating the liquid epoxy resin composition is not particularly limited, and coating or potting with a dispenser, coating by vacuum or atmospheric pressure screen printing, spin coating, reaction injection molding, etc. are conventionally known. The method can be adopted.

The method for curing the liquid epoxy resin composition includes
There is no particular limitation, and a conventionally known curing device such as a closed type curing furnace or a tunnel furnace capable of continuous curing can be adopted.
The heating source is not particularly limited, and it can be performed by a conventionally known method such as hot air circulation, infrared heating, and high frequency heating. The curing temperature and the curing time are 30 at 80 ° C to 250 ° C.
The range of seconds to 15 hours is preferred. If you want to reduce the internal stress of the cured product, pre-cure under the conditions of 80 to 130 ° C for 0.5 hours to 5 hours, and then post-cure under the conditions of 130 to 180 ° C for 0.1 hours to 15 hours. Is preferred, and for the purpose of short-time curing, 150 to 250 ° C., 30 seconds to 3
It is preferable to cure under the condition of 0 minutes.

The thin film cured product of the present invention has a high Tg, a low curing shrinkage ratio, a high insulating property, and is a uniform cured product having no bubbles even when cured at a high temperature of 200 ° C. or higher for a short time.
Even when exposed to a hygroscopic environment after being coated, potted or impregnated with a thin film, the cured product has a high Tg, and the moisture absorption rate of the cured product is low. It can be used as a sealing material.

Concretely, a BGA (ball grid array), which is exemplified by a liquid epoxy resin composition such as an underfill agent for a semiconductor flip chip, a grab top material for wire bonding, and a TAB sealing material, C
Insulation sealing material and chip for surface mounting type semiconductor devices such as SP (chip size package), COG (chip on glass), COB (chip on board) or MCM (multi-chip module) It can be used as an insulating encapsulating material for LED type or optical semiconductor. Further, it can be used as an anisotropic conductive paste, a die bonding paste, a printed circuit board, an adhesive for a multilayer printed circuit board, a through hole joint material, a via hole joint material for a build-up substrate, and the like.

The liquid epoxy resin composition according to the present invention is
The present invention is not limited to a thin film cured product for surface mounting, but can be applied to an insulating encapsulation having a thickness of 2 mm or more or a molded product by a conventionally known method such as potting, casting, filament winding, and lamination. Specifically, mold transformer, mold transformer (current transformer (CT), zero-layer current transformer (Z
CT), transformer for instruments (PT), transformer for installed instruments (ZPT)), gas switch parts (insulating spacers, supporting insulators, operating rods, sealed terminals, bushings, insulating columns, etc.),
Solid insulated switch parts, overhead distribution line automation equipment parts (rotary insulators, voltage detection elements, integrated capacitors, etc.), underground distribution line equipment parts (molded discs, power transformers, etc.), power capacitors, resin insulators, linear It can also be used as a heavy electric insulating sealant such as a coil for a motor car, an impregnating varnish (a generator, a motor, etc.) of a coil for various rotating devices. Also, insulation sealing used in weak electrical fields such as flyback transformers, ignition coils, potting resins for AC capacitors, transparent sealing resins for LEDs, detectors, emitters, photocouplers, film capacitors, impregnating resins for various coils, etc. It can also be used for resins. In addition, it can also be used for various FRP molded products, various coating materials, decorative materials, and the like, which are not necessarily required to have a laminated plate or insulating properties.

[0048]

EXAMPLES The present invention will be described in detail below with reference to examples. The present invention should not be construed as being limited to the following examples. The test method in this example is as follows.

(1) Cured product Tg (7 mm thick, 0.5 mm
Thickness) A liquid epoxy resin composition as a sample is poured into a 68 mmφ metal dish so that the thickness is 7 mm or 0.5 mm, precured at 100 ° C. for 2.5 hours, and then at 150 ° C. for 5 hours.
Glass transition temperature (Tg) of a cured product obtained after post-curing
According to the method described in ASTM D3418-82.
It was measured by the SC method.

(2) Degree of decrease in Tg at the time of thin film curing The value was obtained by subtracting the cured product Tg having a thickness of 7 mm from the cured product Tg having a thickness of 0.5 mm.

(3) Curing Shrinkage Ratio Specific gravity D ₁ of the liquid epoxy resin composition as a sample at 25 ° C. and the same method as in the above measurement (1) were used to prepare 7.
It was calculated from the specific gravity D ₂ of the cured product having a thickness of mm at 25 ° C. by the following formula. Curing shrinkage rate (%) = (D ₂ −D ₁ ) / D ₂ × 100

(4) Number of bubbles generated during curing at 230 ° C. 0.5 g of a liquid epoxy resin composition as a sample was heated at 230 ° C.
It was hung down on a tin plate heated to 1, and cured, and the number of bubbles present in the cured product was counted.

(5) Moisture absorption rate of liquid epoxy resin composition A liquid epoxy resin composition as a sample was placed in a metal dish of 68 mmφ to a thickness of 0.5 mm and weighed precisely,
The weight was measured after being left for 15 hours in a constant temperature and humidity chamber at 25 ° C. and a relative humidity of 60%, and the weight increase rate (% by weight, (resin composition weight after standing-resin composition weight before standing) / The weight of the resin composition before standing × 100) was calculated.

(6) -1 Cured product Tg of liquid epoxy resin composition which has been subjected to moisture absorption (0.5 mm thickness) A liquid epoxy resin composition as a sample is placed in a metal dish of 68 mmφ so as to have a thickness of 0.5 mm. And put it in
After leaving it in a constant temperature and humidity room with a relative humidity of 60% for 15 hours,
Tg of a cured product obtained by pre-curing at 00 ° C. for 2.5 hours and then at 150 ° C. for 5 hours was measured by ASTM D341.
It was measured by the DSC method according to the method described in 8-82.

(6) -2 Cured product Tg of liquid epoxy resin composition which has been subjected to moisture absorption (7 mm thickness) A liquid epoxy resin composition as a sample is placed in a metal dish of 68 mmφ to a thickness of 0.5 mm. , 25 ℃,
The mixture is left for 15 hours in a constant temperature and constant humidity chamber having a relative humidity of 60% and then uniformly mixed. 5 mm of this composition to a thickness of 7 mm
The Tg of the cured product obtained by putting it in a φ plastic test tube and pre-curing it at 100 ° C. for 2.5 hours and then post-curing it at 150 ° C. for 5 hours was measured by the DSC method according to the method described in ASTM D3418-82. It was measured at.

(7) Pressure Cooker Test (PCT Test) of Cured Product of Liquid Epoxy Resin Composition Moisture Absorbed The sample liquid epoxy resin composition is put in a metal dish of 68 mmφ to a thickness of 1.1 mm. Put, 25 ℃,
After leaving it in a constant temperature and humidity room with a relative humidity of 60% for 15 hours,
After pre-curing at 00 ° C. for 2.5 hours, post-curing at 150 ° C. for 5 hours gives a cured product. This cured product was allowed to absorb moisture for 4 days under a pressure cooker tester at 121 ° C. and 0.21 MPa steam pressurization, and then as a moisture absorption rate, a weight increase rate (weight%, (weight after moisture absorption−weight before moisture absorption) / The weight before moisture absorption × 100) was measured. Furthermore, the pressure cooker test was continued under the same conditions, and the number of days when the test piece could not retain its shape due to elution was measured. The lower the moisture absorption rate and the longer the elution days, the better the moisture resistance of the cured product.

(8) Light transmittance A liquid epoxy resin composition as a sample was poured into two 5 mm hard chrome-plated steel plates with a 5 mm spacer sandwiched between them and cured at 120 ° C. for 10 hours to obtain a product. A cured product having a size of 2 cm × 4 cm and a thickness of 5 mm was measured for transmittance (%) at 400 nm with an ultraviolet spectrophotometer. The higher the transmittance, the higher the colorless transparency.

Example 1 HM having a succinic anhydride content of 0.2% by weight as a curing agent
To 97 parts by weight of eNA (proportion of exo form: 60% by weight, acid anhydride equivalent: 180), 1-cyanoethyl-2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., Cureazole 2E4MZ-CN) as a curing accelerator , "2E
4MZ-CN ". ) Add 0.5 parts by weight, 60 ° C
After heating for 30 minutes, the mixture was further stirred and dissolved, and then cooled to room temperature to obtain a transparent liquid curing agent solution at room temperature. To this, 100 parts by weight of bisphenol A diglycidyl ether (manufactured by Tohto Kasei Co., Ltd., Epotote YD-128, epoxy equivalent 185, hereinafter abbreviated as "DGEBA") as an epoxy resin was added, and further thoroughly mixed and vacuum defoamed. A liquid epoxy resin composition was obtained at room temperature. Using this liquid epoxy resin composition, a cured product Tg, a degree of Tg decrease when curing a thin film, a curing shrinkage ratio, a number of bubbles generated when curing at 230 ° C., a moisture absorption rate of the liquid epoxy resin composition, a moisture absorption-treated liquid epoxy resin The cured product of the composition was measured for Tg and PCT tests. The results are shown in Table 1.
Shown in.

Example 2 The curing agent was HMe with a succinic anhydride content of 0.04% by weight.
NA (proportion of exo body: 60% by weight) 80% by weight and H
An epoxy resin composition was obtained in the same manner as in Example 1 except that 96 parts by weight of a mixture (acid anhydride equivalent 177) of 20% by weight of NA (exo-form existence ratio: 50% by weight) was used.
The obtained curing agent liquid and epoxy resin composition were transparent liquids at room temperature. Using this liquid epoxy resin composition,
Cured product Tg, degree of Tg decrease during thin film curing, curing shrinkage ratio, 2
The number of bubbles generated during curing at 30 ° C., the moisture absorption rate of the liquid epoxy resin composition, the Tg of the cured product of the liquid epoxy resin composition subjected to the moisture absorption treatment, and the PCT test were measured. The results are shown in Table 1.

Comparative Example 1 The curing agent was HMeN having a succinic anhydride content of 0.6% by weight.
A (Proportion of Exo Form: 60% by Weight, Acid Anhydride Equivalent 18
0) An epoxy resin composition was obtained in the same manner as in Example 1 except that 97 parts by weight was used. The hardener liquid became cloudy.
The cured product of this liquid epoxy resin composition was colored pink.

Comparative Example 2 The curing agent was 80% by weight of an unsaturated alicyclic dicarboxylic acid anhydride, methylnorbornene-2,3-dicarboxylic acid anhydride.
And a liquid of 20% by weight of norbornene-2,3-dicarboxylic acid anhydride (hereinafter abbreviated as "MeNA") (acid anhydride equivalent 175) were replaced with 95 parts by weight of liquid form in the same manner as in Example 1. An epoxy resin composition was obtained. Using this liquid epoxy resin composition, a cured product Tg and a T when a thin film is cured
The degree of g reduction, cure shrinkage, number of bubbles generated at 230 ° C. curing, moisture absorption of the liquid epoxy resin composition, Tg of the cured liquid epoxy resin composition after moisture absorption treatment, and PCT test were measured. The results are shown in Table 1.

Comparative Example 3 A liquid epoxy resin was prepared in the same manner as in Example 1 except that 89 parts by weight of methylhexahydrophthalic anhydride (an acid anhydride equivalent of 165, hereinafter abbreviated as "MeHHPA") was used as a curing agent. A composition was obtained. Using this liquid epoxy resin composition, a cured product Tg, a degree of Tg decrease when curing a thin film, a curing shrinkage ratio, a number of bubbles generated when curing at 230 ° C., a moisture absorption rate of the liquid epoxy resin composition, a moisture absorption-treated liquid epoxy resin The cured product of the composition was measured for Tg and PCT tests. The results are shown in Table 1.

Comparative Example 4 The procedure was carried out except that 92 parts by weight of methyltetrahydrophthalic anhydride (an acid anhydride equivalent 170, hereinafter abbreviated as "MeTHPA"), which is an unsaturated alicyclic dicarboxylic acid anhydride, was used as a curing agent. A liquid epoxy resin composition was obtained in the same manner as in Example 1. Using this liquid epoxy resin composition, a cured product T
g, degree of Tg reduction during thin film curing, cure shrinkage, number of bubbles generated at 230 ° C. curing, moisture absorption rate of liquid epoxy resin composition, Tg and PCT test of cured product of liquid epoxy resin composition subjected to moisture absorption treatment did. The results are shown in Table 1.

[0064]

Example 3 HM having a succinic anhydride content of 0.2% by weight as a curing agent
To 97 parts by weight of eNA (proportion of exo-form: 60% by weight, acid anhydride equivalent: 180), 2E4MZ-as a curing accelerator.
0.5 part by weight of CN was added, and the mixture was heated at 60 ° C. for 30 minutes, further stirred and dissolved, and then cooled to room temperature to obtain a transparent liquid curing agent solution at room temperature. DGEBA10 as an epoxy resin
0 parts by weight of 296 parts by weight of spherical fused silica (average particle size 4 μm) were mixed and stirred at 60 ° C. for 30 minutes with a universal stirrer and cooled,
A liquid epoxy resin liquid was obtained at room temperature. The curing agent liquid and the epoxy resin liquid were thoroughly mixed at room temperature and vacuum degassing was performed to obtain an epoxy resin composition which was liquid at room temperature. Using this liquid epoxy resin composition, cured product Tg, Tg at the time of thin film curing
Degree of decrease, cure shrinkage, moisture absorption of liquid epoxy resin composition, T of cured product of liquid epoxy resin composition subjected to moisture absorption treatment
The g and PCT tests were measured. The results are shown in Table 2.

Example 4 The curing agent was HMe with a succinic anhydride content of 0.04% by weight.
NA (proportion of exo body: 60% by weight) 80% by weight and H
An epoxy resin composition was obtained in the same manner as in Example 3 except that 96 parts by weight of a mixture (acid anhydride equivalent 177) of 20% by weight of NA (exo-form existence ratio: 50%) was used. The curing agent liquid was transparent at room temperature, and the epoxy resin liquid and the epoxy resin composition were liquid at room temperature. Using this liquid epoxy resin composition, a cured product Tg, a degree of decrease in Tg during thin film curing,
Curing shrinkage, moisture absorption of liquid epoxy resin composition, Tg and PC of cured product of liquid epoxy resin composition subjected to moisture absorption treatment
The T test was measured. The results are shown in Table 2.

Comparative Example 5 A liquid epoxy resin composition was obtained in the same manner as in Example 3 except that the curing agent was changed to 95 parts by weight of MeNA (acid anhydride equivalent 175). Using this liquid epoxy resin composition, a cured product Tg, a degree of Tg reduction during thin film curing, a curing shrinkage ratio, a moisture absorption rate of the liquid epoxy resin composition, a cured product Tg of the liquid epoxy resin composition subjected to moisture absorption, and a PCT The test was measured. The results are shown in Table 2.

Comparative Example 6 A liquid epoxy resin composition was obtained in the same manner as in Example 3 except that 89 parts by weight of MeHHPA (acid anhydride equivalent 165) was used as the curing agent. Using this liquid epoxy resin composition, a cured product Tg, a degree of Tg reduction during thin film curing, a curing shrinkage ratio, a moisture absorption rate of the liquid epoxy resin composition, a cured product Tg of the liquid epoxy resin composition subjected to moisture absorption, and a PCT The test was measured. The results are shown in Table 2.

Comparative Example 7 A liquid epoxy resin composition was obtained in the same manner as in Example 3 except that 92 parts by weight of Me-THPA (anhydride equivalent 170) was used as the curing agent. Using this liquid epoxy resin composition, a cured product Tg, a degree of Tg reduction during thin film curing, a curing shrinkage ratio, a moisture absorption rate of the liquid epoxy resin composition, a cured product Tg of the liquid epoxy resin composition subjected to moisture absorption, and a PCT The test was measured. The results are shown in Table 2.

[0070]

Example 5 HM having a succinic anhydride content of 0.2% by weight as a curing agent
In 97 parts by weight of eNA (proportion of exo form: 60% by weight, acid anhydride equivalent: 180), tetraphenylphosphonium bromide (manufactured by Hokuko Chemical Industry Co., Ltd., T
PP-PB, hereinafter abbreviated as "TPP-PB". ) 1.0 part by weight was added, and the mixture was heated at 60 ° C. for 30 minutes, further stirred and dissolved, and then cooled to room temperature to obtain a transparent curing agent liquid which was liquid at room temperature. Bisphenol diglycidyl ether as an epoxy resin (manufactured by Tohto Kasei Co., Ltd., Epotote YD-
128, epoxy equivalent 185, hereafter abbreviated as "DGEBA". ) 100 parts by weight was added and further mixed well to obtain an epoxy resin composition which was liquid at room temperature. The light transmittance was measured using this liquid epoxy resin composition. The results are shown in Table 3.
Shown in.

Example 6 The curing agent was HMe with a succinic anhydride content of 0.04% by weight.
NA (proportion of exo body: 60% by weight) 80% by weight and H
A liquid epoxy resin composition was obtained in the same manner as in Example 5, except that 96 parts by weight of a mixture (acid anhydride equivalent 177) of 20% by weight of NA (exo isomer content: 50% by weight) was used. The light transmittance was measured using this liquid epoxy resin composition. The results are shown in Table 3.

Comparative Example 8 A liquid epoxy resin composition was obtained in the same manner as in Example 5 except that the curing agent was changed to 95 parts by weight of MeNA (acid anhydride equivalent 175). The light transmittance was measured using this liquid epoxy resin composition. The results are shown in Table 3.

Comparative Example 9 A liquid epoxy resin composition was obtained in the same manner as in Example 5 except that the curing agent was changed to 92 parts by weight of MeTHPA (acid anhydride equivalent 170). The light transmittance was measured using this liquid epoxy resin composition. The results are shown in Table 3.

[0075]

As is clear from Tables 1 and 2, the thin film cured product of the present invention has a high Tg, a small decrease in Tg as compared with a cured product of 7 mm, and a low shrinkage ratio. Further, it has a low moisture absorption rate, and even when the liquid epoxy resin composition which has been subjected to the moisture absorption treatment is cured, the Tg is not lowered so much and the moisture resistance is excellent. Furthermore, the number of bubbles generated when cured at high temperature is small, and it is possible to cure at high temperature in a short time. Further, from Table 3, it is possible to obtain a colorless and transparent cured product.

On the other hand, the one using MeNA as the curing agent has a low moisture absorption rate of the liquid epoxy resin composition,
Tg of 0.5 mm thick cured product is low, curing shrinkage is high,
The cured product after the moisture absorption treatment has a low Tg, which is inferior to the thin film cured product of the present application (Comparative Examples 2 and 5). Also, M
Those using eHHPA or MeTHPA, Tg of the cured product, cure shrinkage, moisture absorption of the liquid epoxy resin composition,
The Tg of the cured product after the moisture absorption treatment and the PCT test result are inferior to those of the thin film cured product of the present application (Comparative Example 3, Comparative Example 4, Comparative Example 5, Comparative Example 6). Also, MeNA or MeT
In the case of using HPA, the cured product is colored from yellow to brown and is not suitable for transparent use (Comparative Examples 8 and 9).

[0078]

The thin film cured product of the present invention is a uniform cured product having a high Tg, a low curing shrinkage ratio, a high insulating property, and no bubbles even when cured at a high temperature of 200 ° C. or higher for a short time. Furthermore,
Even when a liquid epoxy resin composition that has been applied, potted or impregnated with a thin film and then exposed to a hygroscopic environment is cured, the cured product has a high Tg and a low moisture absorption rate of the cured product. Since it is a sealing material that has both, it is particularly suitable as a surface mounting type insulating sealing material.
Surface mounting type such as A (ball grid array), CSP (chip size package), COG (chip on glass), COB (chip on board) or MCM (multi-chip module) It can be used industrially in a wide range of fields including an insulating material such as a sealing material for a semiconductor device and a sealing material for a chip type LED or an optical semiconductor.

Continued front page    F-term (reference) 4J036 AA01 AB01 AB07 AC01 AD01                       AD08 AG00 AG06 AJ01 AJ08                       AJ09 DA02 DA04 DB15 DB21                       DC02 DC41 DD07 DD09 FA01                       FA02 FA03 FA05 FA06 JA07                 4M109 AA01 BA03 CA04 CA12 EA02                       EB02 EB04 EB12 EC01 GA01

Claims (5)

[Claims] 1. An epoxy resin (A), a curing agent (B),
(C) A thin film cured product of a liquid epoxy resin composition containing a curing accelerator as an essential component, wherein the main component of the (B) curing agent is methylnorbornane-2,3-dicarboxylic acid anhydride, (B) A thin film cured product of a liquid epoxy resin composition, wherein the succinic anhydride in the curing agent is 0.4% by weight or less. 2. An epoxy resin (A), a curing agent (B),
A thin film cured product of a liquid epoxy resin composition comprising (C) a curing accelerator and (D) an inorganic filler as essential components,
Liquid epoxy resin composition, wherein the main component of the curing agent is methylnorbornane-2,3-dicarboxylic acid anhydride, and (B) the succinic anhydride content in the curing agent is 0.4% by weight or less. Thin film cured product of. 3. The curing agent (B) is methylnorbornane-
2,3-Dicarboxylic anhydride and norbornane-2,3-
It consists of dicarboxylic acid anhydride, It is characterized by the above-mentioned.
Alternatively, the thin film cured product according to claim 2. 4. The cured thin film according to any one of claims 1 to 3, wherein the cured thin film has a thickness of 2 mm or less. 5. The thin film cured product according to claim 1, which is obtained by applying or potting the liquid epoxy resin composition to a thickness of 2 mm or less and then curing.