JP2001031939A - Heat-bonding adhesive composition and adhesive sheet or like coated therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-bonding adhesive composition that can develop high adhesive strength and excellent heat resistance upon being subjected to low- pressure short-time heat bonding and does not undergo abnormal peel in a heating test of a sample subjected to humid conditions by adding an inorganic filler to a copolymer comprising a (meth)acrylic ester with a monoethylenically unsaturated monomer copolymerizable therewith. SOLUTION: This composition comprises 100 pts.wt. copolymer comprising 70-99 wt.% (meth)acrylic ester represented by the formula with 30-1 wt.% monoethylenically unsaturated monomer copolymerizable therewith and 10-300 pts.wt. inorganic filler. In the formula, R1 is H or methyl; R2 is methylene, ethylene, or propylene; n is 1-3; and ϕis phenyl or a mono- or di-alkyl- substituted phenyl. It is desirable that the composition additionally contains 3-30 pts.wt., per 100 pts.wt. copolymer, flow-improving resin having a softening point of 80-200 deg.C and 5-30 pts.wt., per 100 pts.wt. copolymer, epoxy resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-adhesive composition used for fixing electronic parts and the like, and an adhesive sheet in the form of a sheet or tape.

[0002]

2. Description of the Related Art In recent years, various joining materials have been used for fixing electronic parts. In this type of application, it is necessary to have not only strong adhesiveness but also high heat resistance that can withstand solder reflow when mounting an electronic component on a substrate. In addition, in this type of application, in general, a thermal test such as solder heat resistance is performed after putting the device under humidifying conditions for the purpose of ensuring the reliability of the electronic device. In this case, if the water absorption of the bonding material is large, the moisture absorbed during the thermal test is vaporized and expanded, causing abnormal peeling of the bonding surface. Therefore, it is desired that the bonding material has a low water absorption.

Hitherto, thermosetting adhesive sheets have been known as a bonding material for fixing electronic parts.
These include those using an epoxy / rubber adhesive and those using a polyimide adhesive. Although these bonding materials can be satisfied to some extent in terms of adhesiveness and heat resistance, they have a problem of causing abnormal peeling in a heat test after the humidification condition is applied because of high water absorption. Further, in the case of adhesive sheets using a polyimide-based adhesive, there is another problem that high pressure and a long time are required for the heat bonding treatment, resulting in poor workability.

[0004]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention exhibits a strong adhesive strength and excellent heat resistance by a low-pressure, short-time heat-bonding treatment, and a thermal test after humidifying conditions have been introduced. It is an object of the present invention to provide a highly reliable heat-adhesive composition and its adhesive sheets which do not cause problems such as peeling abnormality.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the above object, and as a result, have found that a copolymer of a monomer mixture containing a (meth) acrylate ester having a specific molecular structure as a main component is used as a main component. As a result, when a specific amount of inorganic filler is added to this, it exhibits strong adhesive strength and excellent heat resistance due to low-pressure, short-time heat bonding treatment, and peels off even in a thermal test after humidifying conditions The present inventors have found that a highly reliable heat-adhesive composition and an adhesive sheet thereof can be obtained without problems such as abnormalities, and have completed the present invention.

That is, the present invention provides the following formula (1): (Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methylene group, an ethylene group or a propylene group, n is an integer of 1 to 3, and φ is a phenyl group, a monoalkyl-substituted phenyl group or a dialkyl-substituted phenyl group. 70) to 99% by weight of a (meth) acrylate represented by the formula) and 30 to 1% by weight of a monoethylenically unsaturated monomer copolymerizable therewith.
(1) A heat-adhesive composition (Claim 1), characterized in that 10 to 300 parts by weight of an inorganic filler is contained in 100 parts by weight of a copolymer of a monomer mixture comprising:

In particular, the present invention provides a heat-adhesive composition having the above constitution, wherein the copolymer is a polymer obtained by irradiation with radiation such as ultraviolet rays (claim 2); In addition to the filler, 3 to 30 flowability-imparting resins having a softening point of 80 to 200 ° C per 100 parts by weight of the copolymer.
5 parts by weight of the epoxy resin per 100 parts by weight of the copolymer in addition to the above-mentioned copolymer and the inorganic filler.
The present invention relates to the heat-adhesive composition having the above-mentioned constitution, which contains 0 parts by weight. Further, the present invention provides a sheet-like or tape-like adhesive sheet having a layer made of the above-mentioned heat-adhesive composition on one or both sides of a substrate. Item 5).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The (meth) acrylate represented by the formula (1) in the present invention is a homopolymer having a Tg of
Is -30 ° C or higher, preferably -10 ° C or higher. As a typical example, phenoxyethyl (meth)
Acrylate, phenoxypropyl (meth) acrylate
And nonylphenoxyethyl (meth) acrylate and nonylphenoxypropyl (meth) acrylate. Further, esters of ethylene oxide adducts such as phenol, cresol, and nonylphenol, and propylene oxide adducts (up to 3 moles added) with (meth) acrylic acid are also preferably used. One or more of these may be used.

In the present invention, the monoethylenically unsaturated monomer copolymerizable with the (meth) acrylic acid ester represented by the above formula (1) has a functional group or a polar group contained therein which is a copolymer. Is used for improving or modifying the heat resistance and adhesiveness of the heat-adhesive composition by being introduced into the molecule. Such monomers include (meth) acrylic acid, itaconic acid, caprolactone-modified (meth) acrylate, sulfopropyl (meth) acrylate, hydroxyalkyl (meth) acrylate, and cyanoalkyl (meth) acrylate. ) Acrylate, (meth) acrylamide, substituted (meth) acrylamide, N-vinylcaprolactam,
Examples thereof include (meth) acrylonitrile, 2-methoxyethyl (meth) acrylate, glycidyl (meth) acrylate, and vinyl acetate. One or more of these may be used.

In the present invention, the ratio of the (meth) acrylic acid ester represented by the above formula (1) and the monoethylenically unsaturated monomer copolymerizable therewith is determined by the former (meth) acrylic acid. The acid ester is 70 to 99% by weight, preferably 85 to 95% by weight, and the monoethylenically unsaturated monomer copolymerizable therewith is 30 to 1% by weight, preferably 15 to 95% by weight.
The content is preferably set to 5% by weight, and by using in such a range, the balance between heat resistance and adhesiveness can be well balanced.

In the present invention, such a monomer mixture is polymerized to produce a copolymer which is usually non-tacky (or low-tacky) at room temperature. For the polymerization, an appropriate polymerization method such as a solution polymerization method, an emulsion polymerization method, and a bulk polymerization method can be adopted. Above all, a bulk polymerization method by irradiation with radiation such as ultraviolet rays or electron beams is preferable. According to this, there is no need to worry about corrosion of electronic components due to residual organic solvent, swelling, peeling, displacement due to vaporization and expansion at high temperature, contamination by emulsifier bleed, poor adhesion, and reduced moisture resistance. The molecular weight of the polymer can be increased by irradiating the target with weak ultraviolet light, etc.
Particularly, it is possible to prepare a heat-adhesive composition having good heat resistance. In the polymerization, a general thermal polymerization initiator or a photopolymerization initiator is used as a polymerization catalyst.Also, potassium persulfate, ammonium persulfate, hydrogen peroxide and the like, and a redox initiator including these and a reducing agent are also used. Used.

In the present invention, the copolymer thus obtained is used as a main component, and an inorganic filler is further added thereto to obtain a heat-adhesive composition. By blending the inorganic filler, it is possible to reduce the water absorption of the heat-adhesive composition,
In addition, due to the increase in the thermal conductivity, effects such as shortening of the heat bonding time and the curing time can be achieved, and further, the workability is improved. Examples of such inorganic fillers include:
SiO ₂ , TiB ₂ , BN, Si ₃ N ₄ , TiO ₂ , M
gO, NiO, Al ₂ O ₃ , Fe ₂ O _{3 and the} like can be mentioned. These inorganic fillers have an average particle size of 0.1.
It is good to be 5 to 250 μm, preferably 1 to 100 μm, more preferably 5 to 30 μm. The particle shape may be any shape such as a spherical shape, a needle shape, a flake shape, and a star shape. The choice of shape can be determined by the rheological properties of the copolymer and the rheological properties of the final thermoadhesive composition.

The amount of the inorganic filler used is as follows.
The amount is preferably 10 to 300 parts by weight, more preferably 10 to 100 parts by weight, per 100 parts by weight of the copolymer. If the amount is less than 10 parts by weight, the effect of lowering the water absorption of the heat-adhesive composition will be poor, and if it is more than 300 parts by weight, the adhesiveness will be impaired, and the adhesion at high temperatures will be reduced. As a result, the adhesive fixing power is poor.

The heat-adhesive composition of the present invention contains, in addition to the above-mentioned copolymer and inorganic filler, a softening point (or melting point).
Can be blended with a fluidity-imparting resin at 80 to 200 ° C, preferably 100 to 200 ° C, more preferably 120 to 150 ° C. According to this, an appropriate fluidity can be imparted to the composition, and a strong adhesive strength can be obtained by a low-pressure, short-time heating adhesive treatment. The softening point of the fluidity-imparting resin is 80 ° C
A lower value is advantageous for low-pressure, short-time adhesion, but results in insufficient heat resistance. When the temperature exceeds 200 ° C., it does not function as a fluidity-imparting component, and the above effects are impaired.

As such a fluidity-imparting resin, any of various resins generally known as tackifier resins such as rosin-based, terpene-based, synthetic petroleum-based, phenol-based, and xylene-based resins can be used. Of these, phenolic resins are most preferred for applications where heat resistance is particularly required. The amount of the fluidity-imparting resin used is in the range of 3 to 30 parts by weight, preferably 5 to 1 part by weight per 100 parts by weight of the copolymer.
Within the range of 5 parts by weight, it is appropriately determined according to the type and the type of the copolymer. If the amount is too small, it will not function as a fluid component, and the above effect will be impaired. If it is too large, it is advantageous for low pressure and short-time bonding, but the heat resistance will be insufficient.

Further, by adding an epoxy resin to the heat-adhesive composition of the present invention in addition to the above-mentioned components, the adhesive strength and heat resistance after heat bonding can be further improved. As such an epoxy resin,
As the compound having two or more epoxy groups in the molecule, bisphenol epoxy resin, aliphatic epoxy resin, phenolic epoxy resin, halogenated bisphenol epoxy resin and the like are preferably used. The amount of the epoxy resin used is in the range of 5 to 30 parts by weight, preferably in the range of 5 to 20 parts by weight, per 100 parts by weight of the copolymer, depending on the type and the type of the copolymer.
It is determined as appropriate. If the amount is too small, the above effects are impaired. If the amount is too large, inconveniences such as a decrease in heat resistance under continuous high-temperature use are likely to occur.

Furthermore, in the heat-adhesive composition of the present invention, an isocyanate-based or epoxy-based cross-linking agent can be blended as a cross-linking agent in order to improve the holding characteristics as an adhesive. When the copolymer is obtained by bulk polymerization by irradiation of radiation such as ultraviolet rays, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) ) Polyfunctional (meta) such as acrylate, 1,2-ethyleneglycol di (meth) acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol di (meth) acrylate Acrylate can be added.

The amount of such a cross-linking agent or cross-linking agent comprising a polyfunctional (meth) acrylate may be used in an amount of 0.1 to 100 parts by weight of the copolymer (or a monomer mixture thereof).
The amount is preferably from 0.5 to 5 parts by weight, more preferably from 0.1 to 3 parts by weight. When using multifunctional (meth) acrylate,
Within the above range, the case of bifunctionality is large, and the case of trifunctional or more functional groups is small. If the amount of the cross-linking agent is too small, the degree of cross-linking after polymerization is lowered, and the retention properties are reduced.If the amount is too large, the elastic modulus becomes extremely high, causing a decrease in adhesion such as poor adhesion. Cheap.

The heat-adhesive composition of the present invention may further contain, if necessary, various known additives such as a silane coupling agent, a plasticizer, a softener, a filler, a pigment, a dye and an antioxidant. The composition can be added to such an extent that the various properties of the composition are not reduced.

The adhesive sheets of the present invention are provided on one or both sides of a substrate with a layer comprising the above-mentioned composition having a thermal adhesive composition having a thickness of usually 10 to 200 μm. It is in the form of a tape or tape. The above-mentioned layer is obtained in advance by a suitable polymerization method, a copolymer, a component such as an inorganic filler and a fluidity-imparting resin, an epoxy resin, a cross-linking agent is added to prepare a heat-adhesive composition. It can be formed by a method of coating on a base material and, if necessary, performing a crosslinking treatment by heating or the like. Further, more preferably, a radiation polymerizable composition obtained by adding components such as an inorganic filler, a fluidity-imparting resin, an epoxy resin, and a polyfunctional (meth) acrylate to a monomer mixture before polymerization or a partial polymer thereof. It is preferable to adopt a method of preparing a polymer, coating the material on a base material, irradiating it with radiation such as ultraviolet rays, polymerizing the polymer, and forming a layer simultaneously with the synthesis of the copolymer.

According to the above-mentioned radiation irradiation method, particularly good results can be obtained in improving the heat resistance. Irradiation with ultraviolet rays is preferably performed in an atmosphere without oxygen replaced by an inert gas such as nitrogen gas, or in a state where the air is shut off by coating with a film that is transparent to ultraviolet rays. The ultraviolet rays used are electromagnetic radiation having a wavelength range of about 180 to 460 nm, but electromagnetic radiation having a longer wavelength or a shorter wavelength may be used. As a source of the ultraviolet rays, a general irradiation device such as a mercury arc, a carbon arc, a low-pressure mercury lamp, a medium / high-pressure mercury lamp, and a metallohalide lamp is used. The intensity of the ultraviolet light is determined by the distance to the irradiation object, the voltage, the irradiation time, and the like.

As the base material, a non-peelable base material such as a plastic film such as a polyimide film, a polyester film, or a polytetrafluoroethylene film, or a fibrous base material, or a peelable base material such as a release paper can be used. . In the case of a peelable substrate, a layer formed of the heat-adhesive composition formed thereon may be finally transferred onto a non-peelable substrate. The adhesive sheets of the present invention include both those using such a non-peelable substrate and those using a release substrate.

The adhesive sheets of the present invention are usually non-adhesive or low-adhesive at room temperature, but can be adhered to an adherend with high adhesive strength by a low-pressure, short-time heat-adhesion treatment. Good heat resistance after bonding. Demonstrates heat resistance to withstand continuous use at high temperatures of 80 ° C or more and use in soldering process. Low water absorption. Abnormal peeling in thermal test after humidification. It does not cause any problems such as the above, and has excellent reliability. For this reason, it is used for fixing applications such as electronic parts, and as a joining material for heat-resistant films and metal plates.
In addition, it can be used for a wide range of applications utilizing the above features.

[0024]

Next, an embodiment of the present invention will be described in more detail. In the following, “parts” means “parts by weight”.

Example 1 95 parts of phenoxyethyl acrylate, 5 parts of acrylic acid, and 210 parts of ethyl acetate were used as a solvent in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer, and a stirrer. 0.3 parts of benzoyl oxide was added and polymerized in a stream of nitrogen to obtain a copolymer solution having a solid content of about 30% by weight. In this solution,
Per 100 parts of the solid content, silica powder [trade name “Admafine SO-E5” manufactured by Admatex Co., Ltd.] 5
0 parts and 1 part of a polyfunctional isocyanate-based cross-linking agent were uniformly mixed to prepare a solution of the heat-adhesive composition. Next, the solution of the heat-adhesive composition was applied on a peelable substrate,
A drying treatment was performed at 5 ° C. for 5 minutes to form a layer of the heat-adhesive composition having a thickness of 100 μm, thereby producing an adhesive sheet.

Example 2 In a four-necked flask, phenoxyethyl acrylate 90 was added.
Parts, acryloyl morpholin 5 parts, acrylic acid 5 parts,
2,2-dimethoxy-2-phenylacetophenone 0.
In a nitrogen atmosphere, ultraviolet rays were irradiated and partially photopolymerized to obtain a syrup having a viscosity of about 30 poise. To 100 parts of the partially polymerized syrup, 50 parts of silica powder (same as that described in Example 1) and 0.3 part of 1,6-hexanediol diacrylate as a cross-linking agent were uniformly mixed, and then mixed. A polymerizable composition was prepared. Next, this photopolymerizable composition was applied on a peelable substrate, and 90
Irradiation with ultraviolet rays of 0 mj / cm ² causes photopolymerization.
A layer of a heat-adhesive composition having a thickness of 0 μm was formed to prepare an adhesive sheet.

Example 3 In place of 90 parts of phenoxyethyl acrylate, 90 parts of an ester of cresol with an ethylene oxide adduct (additional mole number: 1) and acrylic acid were used. A photopolymerizable composition was prepared in the same manner as in Example 2. Further, using this photopolymerizable composition, an adhesive sheet having a layer of a heat-adhesive composition having a thickness of 100 μm was produced in the same manner as in Example 2.

Example 4 Phenoxyethyl acrylate 95 was placed in a four-necked flask.
, 5 parts of 2-hydroxy-3-phenoxypropyl acrylate and 0.05 part of 2,2-dimethoxy-2-phenylacetophenone, and irradiation with ultraviolet light under a nitrogen atmosphere. Partially photopolymerized to obtain a syrup having a viscosity of about 30 poise. In 100 parts of this partially polymerized syrup,
100 parts of alumina powder (trade name "Admafine AO-809" manufactured by Admatex Co., Ltd.), terpene phenol resin [trade name "Sumilite Resin PR-12603" manufactured by Sumitomo Duyres Co., Ltd., softening point (melting point): 133 DEG C. ] 1
0 parts and 0.2 part of trimethylolpropane triacrylate as a cross-linking agent were uniformly mixed to prepare a photopolymerizable composition. Next, this photopolymerizable composition is applied onto a peelable substrate, and is irradiated with 900 mj / cm ² of ultraviolet light to be photopolymerized to form a 100 μm-thick layer of the heat-adhesive composition. A sheet was made.

Example 5 Phenoxyethyl acrylate 95 was placed in a four-necked flask.
Parts, 5 parts of acrylic acid, and 0.05 parts of 2,2-dimethoxy-2-phenylacetophenone, and under a nitrogen atmosphere, irradiate ultraviolet rays to partially perform photopolymerization to have a viscosity of about 3
A zero poise syrup was obtained. To 100 parts of the partially polymerized syrup, 100 parts of alumina powder (same as described in Example 4), 10 parts of terpene phenol resin (same as described in Example 4), and epoxy resin (oiled shell epoxy) A photopolymerizable composition was prepared by uniformly mixing 10 parts of "Epic Coat 815" (trade name, manufactured by the company) and 0.2 parts of trimethylolpropane triacrylate as a cross-linking agent. This photopolymerizable composition is applied on a peelable substrate, and is irradiated with 900 mj / cm ² of ultraviolet light to be photopolymerized to form a 100 μm-thick layer of the heat-adhesive composition. Was prepared.

Comparative Example 1 A reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer was charged with 210 parts of ethyl acetate as a solvent, 60 parts of butyl acrylate, 35 parts of acrylonitrile, and 5 parts of acrylic acid.
And 0.3 parts of benzoyl peroxide, and polymerized in a nitrogen stream to obtain a copolymer solution having a solid content of about 30% by weight. To this solution, 50 parts of silica powder (same as that described in Example 1) and 1 part of a polyfunctional isocyanate-based crosslinking agent were uniformly mixed per 100 parts of the solid content to prepare an adhesive solution. . Next, this adhesive solution was applied on a peelable base material, and dried at 130 ° C. for 5 minutes to obtain a thickness of 100 μm.
An adhesive layer having a thickness of μm was formed to prepare an adhesive sheet.

Comparative Example 2 A four-necked flask was charged with 80 parts of isooctyl acrylate,
Acrylic acid (20 parts) and 2,2-dimethoxy-2-phenylacetophenone (0.05 part) were charged, and ultraviolet light was irradiated under a nitrogen atmosphere to partially photopolymerize the mixture. A syrup having a viscosity of about 30 poise was obtained. Obtained. This partially polymerized syrup 100
In a part, silica powder (same as that described in Example 1) 50
Parts and 0.3 part of 1,6-hexanediol diacrylate as a crosslinking agent were uniformly mixed to prepare a photopolymerizable composition. Next, this photopolymerizable composition is applied on a peelable substrate, and is irradiated with 900 mj / cm ² of ultraviolet light to be photopolymerized to form an adhesive layer having a thickness of 100 μm. Produced.

Comparative Example 3 In a four-necked flask, phenoxyethyl acrylate 90 was added.
Parts, acryloyl morpholin 5 parts, acrylic acid 5 parts,
2,2-dimethoxy-2-phenylacetophenone 0.
In a nitrogen atmosphere, ultraviolet rays were irradiated and partially photopolymerized to obtain a syrup having a viscosity of about 30 poise. To 100 parts of the partially polymerized syrup was added 0.3 g of 1,6-hexanedioldiol acrylate as a crosslinking agent.
The parts were uniformly mixed to prepare a photopolymerizable composition. Next, this photopolymerizable composition was applied on a peelable substrate, and 90
Irradiation with ultraviolet rays of 0 mj / cm ² causes photopolymerization.
A layer of a heat-adhesive composition having a thickness of 0 μm was formed to prepare an adhesive sheet.

Comparative Example 4 Phenoxyethyl acrylate 95 was placed in a four-necked flask.
Parts, 5 parts of acrylic acid, and 0.05 parts of 2,2-dimethoxy-2-phenylacetophenone, and under a nitrogen atmosphere, irradiate ultraviolet rays to partially perform photopolymerization to have a viscosity of about 3
A zero poise syrup was obtained. To 100 parts of the partially polymerized syrup, 10 parts of a terpene phenol resin (same as that described in Example 4), 10 parts of an epoxy resin (same as that described in Example 5), and trimethylol as a cross-linking agent
A photopolymerizable composition was prepared by uniformly mixing 0.2 parts of propane triacrylate. Next, this photopolymerizable composition is applied onto a peelable substrate, and is irradiated with 900 mj / cm ² of ultraviolet light to be photopolymerized to form a 100 μm-thick layer of the heat-adhesive composition. A sheet was made.

Each of the adhesive sheets of Examples 1 to 5 and Comparative Examples 1 to 4 was subjected to an adhesive strength test, a high-temperature holding force test and a humidification heat resistance test by the following methods. The results of these tests were as shown in Table 1.

<Adhesive Strength Test> An adhesive sheet cut to a width of 10 mm and a length of 50 mm was laminated on a 75 μm-thick polyimide film by a laminator (temperature: 100 ° C., pressure: 5 kg / cm).
² , speed: 2m / min) and this is SUS
304 was bonded by a press machine (temperature: 150 ° C., time: 1 second, pressure: 5 kg / cm ² ). After subjecting this sample to heat treatment at 150 ° C. for 1 hour, it was pulled in a 90 ° direction at a pulling speed of 50 mm / min, and the center value was measured as 90 ° peel adhesion strength.

<High temperature holding force test> The adhesive sheet cut into a square of 15 mm was attached to an aluminum plate having a thickness of 0.5 mm, and a press machine (temperature: 150 ° C., time: 1 second, pressure:
5 kg / cm ² ). About this sample,
After a heat treatment at 150 ° C. for 1 hour, a load of 1 kg was applied in the shearing direction, the sample was allowed to stand in an atmosphere of 100 ° C., and the time required for the sample to fall was measured.

<Humidification heat resistance test> An adhesive sheet cut to a width of 50 mm and a length of 50 mm was laminated on a 75 μm-thick polyimide film by a laminator (temperature: 100 ° C., pressure: 5 kg / cm).
² , speed: 2m / min) and this is 30mm
Press machine (temperature: 150 ° C, time:
The bonding was performed for 1 second at a pressure of 5 kg / cm ² ). This sample was subjected to a heat treatment at 150 ° C. for 1 hour, and then left under a humidified condition of 60 ° C. and 90% RH for 168 hours. Thereafter, the SUS304 surface was left on the hot plate and treated for 60 seconds. At that time, the temperature of the hot plate where the peeling abnormality occurred was measured and evaluated as the heat resistance after the humidification condition was introduced.

[0038]

As is evident from the results shown in Table 1 above, each of the adhesive sheets of Examples 1 to 5 of the present invention shows a large adhesive strength by a low-pressure, short-time heat bonding treatment, It can be seen that even after continuous standing, there is little decrease in the adhesive strength, the heat resistance is excellent, and the heat test after the humidification condition is applied is also sufficiently satisfactory.

On the other hand, each of the adhesive sheets of Comparative Examples 1 and 2
Since the main component is a copolymer mainly composed of (meth) acrylic acid alkyl ester, it is difficult to balance the adhesive strength test with the heat test after the humidification condition is applied. Further, since each of the adhesive sheets of Comparative Examples 3 and 4 did not contain an inorganic filler, the temperature in the humidification heat resistance test was lowered, and the heat test after the humidification condition was input was sufficiently satisfied. Can not.

[0041]

As described above, in the present invention, a copolymer of a monomer mixture mainly composed of a (meth) acrylate having a specific molecular structure as a main component, and a specific amount of an inorganic filler The combination of low pressure and short-time heat bonding provides strong bonding strength and excellent heat resistance, and also causes problems such as peeling abnormalities in the heat test after humidification. The present invention can provide a heat-adhesive composition having excellent reliability and an adhesive sheet thereof.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4J004 AA04 AA10 AA12 AA13 AA18 AB01 AB03 CA03 CA06 CC02 DB03 EA05 FA05 4J040 BA202 DF061 DN032 DN072 EB052 EB082 EC032 EC062 EC072 EC152 EC231 EL012 GA05 GA07 GA11 HA13 GA25 JB01 KA01 KA03 KA25 KA26 KA42 LA02 LA03 LA05 LA06 LA07 LA08 NA19

Claims (5)

[Claims] 1. The following equation (1): (Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a methylene group, an ethylene group or a propylene group, n is an integer of 1 to 3, and φ is a phenyl group, a monoalkyl-substituted phenyl group or a dialkyl-substituted phenyl group. 70) to 99% by weight of a (meth) acrylate represented by the formula) and 30 to 1% by weight of a monoethylenically unsaturated monomer copolymerizable therewith.
A heat-adhesive composition comprising 10 to 300 parts by weight of an inorganic filler in 100 parts by weight of a copolymer of a monomer mixture comprising: 2. The heat-adhesive composition according to claim 1, wherein the copolymer is a polymer obtained by irradiation with radiation such as ultraviolet rays. 3. The composition according to claim 1, further comprising, in addition to the copolymer and the inorganic filler, 3 to 30 parts by weight of a fluidity-imparting resin having a softening point of 80 to 200 ° C. per 100 parts by weight of the copolymer. 3. The heat-adhesive composition according to 1. 4. The heat-adhesive composition according to claim 1, further comprising 5 to 30 parts by weight of an epoxy resin per 100 parts by weight of the copolymer, in addition to the copolymer and the inorganic filler. object. 5. An adhesive sheet having a layer comprising the heat-adhesive composition according to claim 1 on one or both sides of a substrate.