JP2003268337A - Adhesive composition and adhesive sheet - Google Patents

Abstract

(57) [Summary] A conventional epoxy resin-based adhesive sheet is attached to a circuit board and formed into an adhesive by heating under pressure of a press machine or the like. Has an issue that the area is 1.5 to 3.0 times the initial area. An adhesive composition comprising 100 parts by weight of an epoxy resin, 100 parts by weight of a thermoplastic resin, and 1 to 80 parts by weight of a latent curing agent, comprises a heat-polymerizable compound 10 to 200 parts
Parts by weight, and 0.1 to 10 parts by weight of a heat polymerization initiator.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive composition which is laminated at room temperature like an ordinary pressure-sensitive adhesive, and then cured by heating to form an adhesive, and a sheet-like adhesive composition. The adhesive / bonding sheet formed in the above.

[0002]

2. Description of the Related Art In recent years, with the demand for smaller, thinner and lighter electric products such as mobile phones and mobile devices, there has been a strong demand for smaller, thinner and highly integrated semiconductor elements, substrates and the like. There is.

As a technology to meet these requirements, expectations are high for a tacky adhesive composition and a thermosetting adhesive sheet used in the manufacture of mounted parts such as semiconductor chips,
Adhesive composition and thermosetting adhesive sheet having various functions and characteristics are used.

A tacky adhesive sheet is an adhesive material that can be bonded at room temperature like ordinary pressure-sensitive adhesive tapes, and is cured (post-cured) by heating after bonding to form an adhesive, which exhibits excellent adhesive performance. is there. Therefore, this adhesive / adhesive sheet does not need to be applied to the adherend before adhesion unlike ordinary liquid adhesives, and has the advantage that it can be re-attached and positioning is easy. Excellent workability and usability.

However, in the conventional epoxy resin adhesive / adhesive sheet, when the adhesive / adhesive sheet is pasted on a circuit board and made into an adhesive by heating under pressure of a press or the like, the area of the adhesive / adhesive sheet is initially set. There is a problem that the area becomes 1.5 to 3.0 times.

[0006]

SUMMARY OF THE INVENTION Therefore, according to the present invention, even if an adhesive composition or an adhesive sheet is pasted on a circuit board and made into an adhesive by heating under pressure, fluidity (sticking It is an object of the present invention to provide an adhesive composition and an adhesive sheet with less change in the combined area).

[0007]

Means for Solving the Problems As a result of earnest research, the present inventor has found that the adhesive composition contains a heat-polymerizable compound and a heat-polymerization initiator, and thus the adhesive composition or adhesive composition It was found that the fluidity (change in the bonding area) can be small even if the adhesive sheet is bonded to the circuit board and made into an adhesive by heating under pressure, and the present invention has been completed. It was.

That is, the adhesive composition of the present invention comprises 100 parts by weight of an epoxy resin, 100 parts by weight of a thermoplastic resin, and 1 to 80 parts by weight of a latent curing agent. The composition is characterized by containing 10 to 200 parts by weight of the functional compound and 0.1 to 10 parts by weight of a thermal polymerization initiator, thereby reducing the fluidity (change in the bonding area).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The heat-polymerizable compound which is a feature of the present invention is
The adhesive composition according to the present invention is adopted to prevent the bonded area from increasing even when heated, and specifically, it is three-dimensionally reticulated by a heated heating polymerization initiator. It suppresses the fluidity of the entire adhesive (expansion of the bonding area). If the blending ratio of the heat-polymerizable compound is too small, the fluidity is not suppressed, and if it is too large, the heat resistance of the entire composition becomes too low, and a good adhesive cannot be formed. Good parts, preferably 20 to 100 parts by weight.

The heat-polymerizable compound includes monomers and oligomers. The monomer has an acryloyl group or a methacryloyl group, and specific examples thereof include a monofunctional acrylate having one in each molecule and a polyfunctional acrylate having two or more. The oligomer is preferably a low-molecular weight compound having two or more vinyl-based functional groups, and specific examples thereof include urethane acrylate, epoxy acrylate, polyester acrylate and the like, which are single or mixed. The heat-polymerizable compound is not particularly limited, but preferably has a weight average molecular weight of 300 to 30,000. These heat-polymerizable compounds can be used alone or in combination of two or more.

Examples of the monofunctional acrylate exemplified as the monomer include, for example, a carboxyl group-containing monomer such as acrylic acid, maleic acid, fumaric acid and itaconic acid or an anhydride thereof; acrylonitrile, N-vinylpyrrolidone,
N-vinylcaprolactam, acryloylmorpholine,
Acrylamide, dimethylaminoethyl acrylate,
Nitrogen-containing monomers such as diethylaminoethyl acrylate and dimethylaminopropyl acrylamide; hydroxyl-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, polyoxyethylene acrylate, polyoxypropylene acrylate and caprolactone modified acrylate. There is.

Further, as the polyfunctional acrylate,
For example, hexanediol diacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, acrylic acid. There are allyl, vinyl acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate.

As the urethane acrylate, for example, polyester urethane acrylate, polyether urethane acrylate, tetrafunctional urethane acrylate, 6
There is a functional urethane acrylate.

The above-mentioned epoxy acrylate is synthesized by a reaction of an epoxy group with acrylic acid or methacrylic acid, and is bisphenol A type, bisphenol S type, bisphenol F type, epoxy oil type, phenol novo. There are a rack type and an alicyclic type.

The polyester acrylate is an acrylate obtained by condensing acrylic acid to the OH group remaining in the polyester skeleton synthesized from a diol, a polyol and a dibasic acid. For example, phthalic anhydride / propylene oxide diol / acryl. Acid, adipic acid / 1,6
-Hexanediol / acrylic acid, trimellitic acid / diethylene glycol / acrylic acid.

The heat-polymerization initiator used in the present invention is adopted as an auxiliary agent for initiating the heat-polymerization of the above-mentioned heat-polymerized compound. Specifically, organic peroxide derivatives and azo-type polymerization initiators are used. However, the azo-based polymerization initiator is preferably an organic peroxide derivative because nitrogen is generated when heated. As a more specific example of the heat polymerization initiator,
There are ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate and azobisisobutyronitrile. Further, if necessary, an amine compound such as triethylamine, tetraethylpentaamine, or dimethylaminoether as a polymerization accelerator may be used in combination.

As the epoxy resin, bisphenol A is used.
Type diglycidyl ether epoxy resin, bisphenol F type diglycidyl ether epoxy resin, bisphenol S type diglycidyl ether epoxy resin, epoxy novolac resin derived from epichlorohydrin and phenol novolac or cresol novolac, phenol novolac type epoxy resin, cresol novolac type Epoxy resin, trishydroxyphenylmethane type epoxy resin, tetraphenylolethane type epoxy resin,
Naphthalene type epoxy resin, dicyclopentadiene phenol type epoxy resin, glycidyl amine, glycidyl ether, biphenyl, alicyclic and the like, various epoxy compounds having two or more glycidyl groups in one molecule, etc. It can be used in combination. These epoxy resins contain impurity ions (Na ⁺ , Cl ^−, etc.)
Alternatively, it is useful for preventing electron migration to use a high-purity product in which hydrolyzable chlorine and the like are reduced to 300 ppm or less.

As the thermoplastic resin used in the present invention, a conventionally known one used as a tacky adhesive composition when used as a mere tacky adhesive composition can be adopted, and in order to make the sheet forming property easier. , Phenoxy resin, polysulfone, polyarylate, polycarbonate, polyphenylene sulfide, polyether sulfone, polyetheramide, and polyetherimide, and these can be used alone or in combination of two or more kinds. If the blending ratio of the heat-polymerization initiator is too small, the unreacted heat-polymerizable compound remains and the fluidity is not suppressed, and if it is too much, the polymer does not have a high molecular weight and causes a problem in adhesiveness and heat resistance, Neither can form a good adhesive. Therefore, 0.1
10 parts by weight is preferable, and 1 to 5 parts by weight is preferable.

As the latent hardener used in the present invention, a conventionally known latent hardener used in the adhesive composition can be adopted, and specifically, a Lewis acid complex, dicyandiamide, an imidazole compound, Acid anhydride curing agent, phenol novolac, aromatic polyamine, amino resin, organic acid hydrazide, diaminomaleonitrile, melamine derivative, polyamine salt, amine imide compound, molecular sieve encapsulating curing agent, latent encapsulation of microencapsulating curing agent The agents may be used alone or in combination of two or more, and preferably, dicyandiamide having an action (curing) temperature of 160 ° C. or higher can be used. By using a dicyandiamide-based latent curing agent exhibiting such a curing temperature, when the adhesive composition of the present invention is applied to a magnetic substance-containing adhesive, mounting of semiconductor elements, magnetic components, substrates, etc. The parts can be glued together.

An inorganic filler may be blended in order to set the thermal conductivity and the dielectric constant of the adhesive composition of the present invention. Alumina, silica, aluminum hydroxide and the like can be used as the inorganic filler. Alumina is a good choice when used in the electrical and electronic fields where heat dissipation is often required. The surface of the inorganic filler may be surface-treated with a silane-based or titanium-based coupling agent. If the blending ratio of the inorganic filler is too small, the desired improvement in thermal conductivity and dielectric constant will not be exhibited, and if it is too large, the fluidity of the blended material will decrease, so that the total solid content is 10 to 60 volume. % Is preferable.

The adhesive composition of the present invention can be manufactured by a conventionally known manufacturing method. For example, it can be produced by uniformly mixing an epoxy resin, a thermoplastic resin, a latent curing agent, a heat-polymerizable compound and a heat-polymerization initiator, and optionally an inorganic filler to be mixed in a solvent.

The pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive sheet by forming it into a sheet.
As an example of the production method in this case, the adhesive composition is applied onto a polyester sheet or the like as a release film, and a solvent is used at a temperature not lower than the activation temperature of the heat polymerization initiator and not higher than the activation temperature of the latent curing agent. There is a way to remove it.

[0024]

EXAMPLES Examples of the present invention will be specifically described with reference to Table 1 while comparing with comparative examples. In addition, the value of each compound in the adhesive agent in Table 1 is parts by weight.

[0025]

[Table 1]

The adhesive composition according to Example 1 was a bisphenol F-type epoxy resin (Dainippon Ink and Chemicals: EXA) having an epoxy equivalent of 175 as an epoxy resin.
830LPV) 100 parts by weight, 100 parts by weight of a phenoxy resin having a weight average molecular weight of 50,000 as a thermoplastic resin (Toto Kasei: YP-50S), 10 parts by weight of dicyandiamide as a latent curing agent, and 6 as a heat-polymerizable compound. 100 parts by weight of a functional urethane acrylate oligomer and 5 parts by weight of peroxydicarbonate (NOF: perloyl TCP) as a thermal polymerization initiator are used as an adhesive composition, and the adhesive composition is toluene. /
It was prepared as a 40% by weight solution by dissolving it in a 1: 1 mixed solvent of MEK (methyl ethyl ketone). The method for forming the tacky-adhesive composition on a tacky-adhesive sheet is as follows.
It is a method of coating on an ET (polyethylene terephthalate) film with an applicator so as to have a thickness of 50 μm after drying, followed by drying in an oven set at 100 ° C. for 10 minutes and peeling from the PET film. It should be noted that when the product is provided, it is conveyed with the PET film attached. In addition, in other Examples and Comparative Examples, the same compounding, compounding ratio, and manufacturing method as in this Example were used, unless otherwise specified.

The characteristic values disclosed in Table 1 are those obtained by evaluating the adhesive / adhesive sheets obtained by the formulations of Examples and Comparative Examples shown in Table 1 by the following test methods.

The area increase rate test in Table 1 is an evaluation of fluidity. Each adhesive sheet is sandwiched between aluminum plates having a thickness of 2 mm, and a load of 3 MPa is applied under reduced pressure.
It was hot pressed at 0 ° C. for 60 minutes. It is the value of B / A using the initial area (A) and the area (B) after heating under pressure with a press. In this test, a value close to 1.0 is preferable.

The copper foil peeling strength in Table 1 was used to evaluate the adhesiveness, and was adopted in order to avoid the influences of the smoothness of the adhesive surface, parallelism, cleanliness, etc. as accurately as possible. The test body was prepared by sandwiching each adhesive sheet between an aluminum plate having a thickness of 2 mm and a copper foil having a thickness of 35 μm, applying a load of 3 MPa under reduced pressure, heat-pressing at 170 ° C. for 60 minutes, and then performing an etching treatment. The copper foil having a width of 10 mm is left. The peel strength was measured according to JIS C 6471. In this test, 1.0 kN / m or more is preferable.

The solder heat resistance in Table 1 is an evaluation of heat resistance, and the test piece used for the above copper foil peeling strength is 300.
The peeling from the copper foil when left to stand for 60 seconds in an atmosphere of ° C was confirmed. In the evaluation shown in Table 1, peeling was visually confirmed to be "x", and peeling was not confirmed to be "o".

In the comprehensive evaluation of Table 1, those which do not satisfy the criteria in the above test results (those which cannot be commercialized) are marked with X, and those which do not meet the criteria are marked with ◯.

In Comparative Example 1, the heat-polymerizable compound contained in the composition of Example 1 was changed to 5 parts by weight, and in Comparative Example 2, the heat-polymerizable compound of Example 1 was added to 250 parts by weight.
It is changed to parts by weight.

In Comparative Example 3, the heat polymerization initiator compounded in the composition of Example 1 was changed to 0.05 parts by weight, and in Comparative Example 4, the heat polymerizable compound of Example 1 was used. 15
It is changed to parts by weight.

As shown in Comparative Example 1, the fluidity was not suppressed when the heat-polymerizable compound was small, and as shown in Comparative Example 2, when the heat-polymerizable compound was large, the adhesiveness and heat resistance were poor. .

As shown in Comparative Example 3, the fluidity was not suppressed when the heat polymerization initiator was small, and as shown in Comparative Example 2, when the heat polymerization initiator was large, the adhesiveness and heat resistance were poor. .

Next, a second embodiment will be described. In Example 2, alumina powder treated with an epoxy-modified silane coupling agent was added to the varnish of Example 1. This compounding ratio is 1200 parts by weight as shown in Table 1. This 1200 parts by weight is blended such that the inorganic filler is 50% by volume based on the total solid content of the blended varnish. Others were manufactured and measured in the same manner as in Example 1.

The tacky-adhesive sheet of Example 2 had the same effect as that of Example 1, but it was possible to impart a thermal conductivity not obtained in Example 1 although not shown in Table 1.

[0038]

According to the present invention, the adhesive composition of the present invention comprises 100 parts by weight of an epoxy resin and 100 parts of a thermoplastic resin.
In a pressure-sensitive adhesive composition having 1 part by weight to 1 to 80 parts by weight of a latent curing agent, 10 to 200 parts by weight of a heat-polymerizable compound and 0.1 to 10 parts by weight of a heat-polymerization initiator are contained. It was possible to reduce the fluidity (change in the bonding area) that occurs during heating under pressure.

In the invention according to claim 2, an inorganic filler is dispersed in the pressure-sensitive adhesive composition, thereby imparting heat conductivity to the pressure-sensitive adhesive composition in addition to the effect of the invention. We were able to.

Further, in the invention according to claim 3,
A tacky-adhesive sheet obtained by forming the tacky-adhesive composition in the form of a sheet, which makes it possible to provide a tacky-adhesive sheet which is easy to bond to an adherend and has a low fluidity.

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Claims (3)

[Claims] 1. A pressure-sensitive adhesive composition comprising 100 parts by weight of an epoxy resin, 100 parts by weight of a thermoplastic resin, and 1 to 80 parts by weight of a latent curing agent.
A tacky-adhesive composition, characterized by containing 0.1 part by weight and 0.1 to 10 parts by weight of a heat polymerization initiator. 2. A tacky-adhesive composition in which an inorganic filler is dispersed in the tacky-adhesive composition according to claim 1. 3. An adhesive / adhesive sheet obtained by forming the adhesive / adhesive composition according to claim 1 or 2 into a sheet form.