JP2001040318A - Curable pressure-sensitive adhesive compositions and curable pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide curable pressure-sensitive adhesive compositions which have excellent tack at normal temperatures before curing, initial tack, and recess and projection follow-up properties and, at the same time, can be cured by light irradiation without requiring heating before or after lamination of an adherend and exhibit excellent adhesion strength and modified follow-up properties after curing. SOLUTION: A curable pressure-sensitive adhesive composition comprises an adhesive, polymer having not less than 0.5 mgKOH/g hydroxyl group, a cationically polymerizable compound excluding the adhesive polymer, and a photo-cationic polymerization initiator and has a storage elastic modulus at 23 deg.C in the dynamic viscoelasticity spectrum of not greater than 0.9×106 Pa and a storage elastic modulus at 23 deg.C after curing of not smaller than 4.0×10 Pa. A curable pressure-sensitive adhesive sheet is obtained by laminating the curable pressure-sensitive adhesive composition on at least one side of a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a curable adhesive composition and a curable adhesive sheet using the same.

[0002]

2. Description of the Related Art A curable pressure-sensitive adhesive sheet or tape (hereinafter simply referred to as "curable pressure-sensitive adhesive sheet") can be bonded at ordinary temperature like a normal pressure-sensitive adhesive tape, and after bonding, it can be bonded by any method. It is an adhesive material that is cured (post-cured) into an adhesive and exhibits excellent adhesive performance. This cured adhesive sheet does not need to be applied before bonding like a normal liquid adhesive, so it is excellent in usability and there is no problem such as protruding or contaminating the surroundings.
In recent years, its use range is expanding.

As a method of curing a curable adhesive sheet, a method of reacting and curing the curable adhesive composition using heat, light or the like as a trigger is generally performed. For example, Japanese Patent Application Laid-Open No. 9-279103 discloses "a photocurable adhesive sheet comprising a high molecular weight polymer such as an acrylic polymer, an epoxy resin, and a cationic photopolymerization initiator". In the case of this curable adhesive sheet, when light is irradiated, the cationic photopolymerization initiator is decomposed to induce cationic polymerization of the epoxy resin, and the epoxy resin is cured to convert the adhesive sheet into an adhesive.

[0004] Such a curable adhesive sheet triggered by light does not require heat in principle, and is suitable for bonding a material having low heat resistance such as a plastic film having a low softening point or a magnetic material. ing. In addition, the curable adhesive sheet that is cured by cationic polymerization, the polymerization proceeds, the curing proceeds, since there is enough time before the tackiness disappears,
During this time, it can be attached to the adherend. For this reason, a curable adhesive composition that cures by cationic polymerization with light as a trigger, unlike conventional light-curable adhesive compositions and light-curable adhesive sheets that do not have tackiness,
There is an advantage that it can be applied to bonding of an opaque material that does not transmit light.

[0005] In recent years, IC cards and ID tags have attracted attention as information media capable of recording and communicating small and high-density information that is convenient for carrying. Since these portable IC information devices are small and lightweight, and may be used in a severe manner, a high degree of reliability is required.

Generally, an IC card or ID tag has an I
C and a module in which the module is mounted in a sandwich with a film material. The IC module is composed of an IC chip and a base material, and has a size of 50 to 200 μm.
m. Due to its thickness, simply sandwiching causes irregularities on the surface. Therefore, for these laminations, usually, a hot-melt type adhesive resin or a liquid adhesive is used, and the adhesive resin is softened, melted or cast to absorb the irregularities. The surface is designed to be flat.

However, in the case of a hot-melt type adhesive resin, the resin is melted to a viscosity at which irregularities can be absorbed and bonded, so that the resin protrudes to the side surface, contaminating the surroundings and removing the protruding portion. There are problems such as necessity. In addition, hot-melt adhesive resins generally have low heat resistance, and thus have problems such as easy peeling and displacement under high temperatures in summer. On the other hand, in addition to the problem of protruding with a liquid adhesive, there is a restriction on the pot life from losing fluidity after compounding a curing agent, and furthermore, there is also an environmental problem because it usually contains an organic solvent. .

[0008]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to have excellent tackiness (tack), initial tackiness, and conformability to irregularities at room temperature before curing. By irradiating light before or after laminating, the curable adhesive composition cures without heating, and exhibits excellent adhesive strength and deformation followability after curing, and the viscosity of the curable adhesive composition. An object of the present invention is to provide a curable adhesive sheet using an adhesive composition.

[0009]

According to a first aspect of the present invention, there is provided a curable adhesive composition comprising: an adhesive polymer having a hydroxyl group of 0.5 mgKOH / g or more; a cationic polymerizable compound excluding the adhesive polymer; Comprising a cationic photopolymerization initiator,
The storage elastic modulus at 23 ° C. in the dynamic viscoelastic spectrum is 0.9 × 10 ⁶ Pa or less, and the storage elastic modulus at 23 ° C. after curing is 4.0 × 10 ⁶ Pa or more.

[0010] According to a second aspect of the present invention, there is provided the curable adhesive composition according to the first aspect, wherein the adhesive polymer is a polyester-based polymer, a polyurethane-based polymer, or a polyether. It is characterized in that it is at least one member selected from a series of polymers.

[0011] The curable adhesive sheet according to claim 3 is
The curable adhesive composition according to claim 1 or 2 is laminated on at least one surface of a support.

The adhesive polymer used in the present invention includes, for example, polyester, polyurethane, polyether, polyamide, acrylic, silicone, and the like.
Polyolefin-based, polyimide-based, polystyrene-based polymers; polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, polyvinyl fluoride, polyvinylidene fluoride, Vinyl polymers such as poly-N-vinylpyrrolidone; adhesive polymers having moderate polarity and excellent adhesion to the adherend surface, such as cellulose-based, protein-based and starch-based natural polymer-based polymers; No. The adhesive polymer may be used alone or in combination of two or more.

In the present invention, it is necessary that the adhesive polymer has a hydroxyl group of 0.5 mg KOH / g or more. The hydroxyl group imparts an appropriate polarity to the curable adhesive composition (hereinafter, simply referred to as “adhesive composition”), and thus has an effect of improving wettability and adhesion to an adherend. Demonstrate. Further, the hydroxyl group becomes a cross-linking point at the time of cationic polymerization of the cationically polymerizable compound described later, and is taken into the cross-linked structure after curing, thereby exhibiting an effect of remarkably improving heat resistance and adhesive strength. If the hydroxyl group content of the adhesive polymer is less than 0.5 mgKOH / g, the above effects cannot be obtained.

In the present invention, the adhesive polymer may have a reactive functional group other than a hydroxyl group.
As the reactive functional group other than the hydroxyl group, for example, a carboxyl group, an epoxy group, an amino group, an isocyanate group,
An organic acid group such as an aziridinyl group, a silanol group, a thiol group or a phosphoric acid group is exemplified.

These reactive functional groups can also impart polarity to the adhesive composition or form a crosslinked structure, and thus have the effect of improving the adhesive strength, cohesive strength, heat resistance, rigidity, etc. .

In the present invention, among the above-mentioned adhesive polymers, an adhesive polymer having a hydroxyl group at a molecular terminal such as a polyester-based polymer, a polyurethane-based polymer and a polyether-based polymer is preferably used. A polymer or a polyurethane polymer is particularly preferably used.

The polyester-based polymer is a generic name of a polymer having a hydroxyl group at a molecular terminal formed by condensation polymerization of a polyol and a polycarboxylic acid, and having various properties by changing the type and combination of the polyol and the polycarboxylic acid. Is obtained.

Specific examples of the polyester-based polymer include, for example, “Byron” series and “Vylonal” series manufactured by Toyobo Co., Ltd., “Elitel” series manufactured by Unitika, and Dainippon Ink and Chemicals, Inc. The trade name "Spinodor" series, the trade name "Takelac" series manufactured by Takeda Pharmaceutical Company, the trade name "Kuraboru" manufactured by Kuraray Co., Ltd., and the like.

The above polyester-based polymers may be used alone or in combination of two or more.

The polyurethane polymer is a general term for polymers formed by addition polymerization of a polyol and a polyfunctional isocyanate compound. Polymers having various properties can be obtained by changing the type and combination of the polyol and the polyfunctional isocyanate compound. can get.

Examples of the polyol include polyester polyols, polyether polyols, polymer polyols, the above-mentioned polyester-based polymers and polyether-based polymers described below. The above polyols may be used alone or in combination of two or more.

Specific examples of the polyfunctional isocyanate compound include, for example, "Coronate" series, trade name, manufactured by Nippon Polyurethane Industry Co., Ltd., "Desmodule" series, trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd., and Takeda Pharmaceutical Co., Ltd. "Takenate" series.
The polyfunctional isocyanate compounds may be used alone or in combination of two or more.

The above-mentioned polyurethane polymers may be used alone or in combination of two or more.

Examples of the polyether polymer include polyethylene glycol, polypropylene glycol, polybutylene glycol and polycaprolactone.
More specifically, for example, a product name “Polyether” series manufactured by Asahi Denka Kogyo KK is exemplified. The above polyether-based polymers may be used alone or in combination of two or more.

These adhesive polymers have a hydroxyl group at the molecular terminal and are incorporated into the crosslinked structure in a linear manner, so that they exhibit the function of increasing the distance between crosslinking points. As a result, the ability of the cured product to follow the deformation is improved, and even when an impact stress is applied to the cured product, stress concentration hardly occurs, and the bonded surface is hardly broken. Therefore, a strong bond that is not easily peeled off even when the joined body is exposed to shock or vibration can be obtained. For example, in a use requiring high reliability such as a contact type IC card, and always exposed to deformation stress. It is suitable for bonding of a joined body. In particular, when a polyester-based polymer or a polyurethane-based polymer or a modified product thereof is used as the adhesive polymer, the above characteristics are further improved.

The cationically polymerizable compound used in the present invention is a compound capable of hardening the adhesive composition by increasing the molecular weight by cationic polymerization. For example, an epoxy group, an alicyclic epoxy group, Cationic polymerizable compounds having a vinyl ether group, a hydroxyl group, an ethyleneimine group, an episulfide group and the like can be mentioned. The cationically polymerizable compounds may be used alone or in combination of two or more.

Among the above cationically polymerizable compounds, an epoxy compound having an epoxy group or an alicyclic epoxy group, or a vinyl ether compound having a vinyl ether group, which is excellent in cationic polymerizability, is preferably used. Epoxy compounds that can exhibit more excellent adhesive strength and heat resistance because of their high properties are particularly preferably used.

The epoxy compound is commercially available as an epoxy resin from, for example, Yuka Shell Epoxy, Asahi Denka Kogyo, Daicel Chemical Industries, and the like. The vinyl ether compound is, for example, a product of the trade name "Rapicure" series. Is commercially available from ISP.

These cationically polymerizable compounds are cationically polymerized by a photo-cationic polymerization initiator described later to form a highly crosslinked structure. Therefore, the elasticity of the cured product of the adhesive composition is increased, and the adhesive strength and the like are improved. Demonstrates the function of significantly improving heat resistance. Further, since a crosslinked structure is formed by the cationic polymerization with the hydroxyl group in the adhesive polymer, a function of suppressing plasticization of the adhesive polymer by heat and improving heat resistance is also exhibited.

The cationically polymerizable compound is not particularly limited, but is preferably liquid at room temperature with a number average molecular weight of 5,000 or less, more preferably 300.
0 or less.

The number average molecular weight of the cationically polymerizable compound is 5
When it exceeds 000, the compatibility with the adhesive polymer is reduced and the adhesive composition causes phase separation, or the wettability to the surface of the adherend is reduced, and the adhesion and the adhesive force are reduced. Sometimes.

When a cationically polymerizable compound which is liquid at room temperature and has a number average molecular weight of 5,000 or less is used, the elasticity of the adhesive composition before curing decreases due to the plasticizing effect on the adhesive polymer. Followability is sufficiently improved.

The functional group equivalent of the cationically polymerizable compound is preferably about 150 to 5000 g-resin / mol. If the functional group equivalent is less than this,
The reactivity is increased, and the working time required for application to the adherend after irradiation may be restricted. If the amount is too large, the reaction speed may be slow, and a long time may be required for curing. However, the amount of the above functional group cannot be univocally determined because it is determined by the desired reaction rate and the curing properties which also depend on the mixing ratio with the adhesive polymer described below.

The amount of the cationic polymerizable compound to be mixed with the adhesive polymer is not particularly limited, but is preferably 10 to 90 parts by weight of the cationic polymerizable compound with respect to 100 parts by weight of the adhesive polymer. .

When the amount of the cationically polymerizable compound is less than 10 parts by weight based on 100 parts by weight of the adhesive polymer,
Because the cohesive force of the cured product is not sufficiently improved, the adhesive strength and heat resistance may be insufficient. Conversely, if the content exceeds 90 parts by weight, the initial adhesive properties cannot be satisfied or the elastic modulus of the cured product is high. In some cases, the impact resistance is lowered, and the material may be easily broken at low temperatures.

The cationic photopolymerization initiator used in the present invention is activated by irradiating light to generate a photocationic polymerization initiator, and the above cationically polymerizable compound is photocationically polymerized at relatively low energy. As long as it can be performed, an ionic photoacid generating type cationic photopolymerization initiator may be used, or a nonionic photoacid generating type photocationic polymerization initiator may be used.

Examples of the ionic photoacid generating type cationic photopolymerization initiator include onium salts such as aryldiazonium salts, diarylhalonium salts, triarylsulfonium salts, and triphenylphosphonium salts; iron-allene complexes; titanocene; And organometallic complexes such as an arylsilanol-aluminum complex.

Examples of the nonionic photoacid generating type photocationic polymerization initiator include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidosulfonate and the like. .

The above cationic photopolymerization initiators may be used alone or in combination of two or more. When two or more cationic photopolymerization initiators are used in combination, multistage curing may be performed using two or more different cationic photopolymerization initiators having different effective active wavelengths. One or more photosensitizers such as benzophenone and 9,10-anthraquinone may be used in combination.

The amount of the cationic photopolymerization initiator added is not particularly limited, and is appropriately set according to the reactivity and molecular weight of the cationically polymerizable compound, the viscoelasticity to be imparted to the adhesive composition, and the like. Just do it.

In the present invention, as the photopolymerization initiator, one or two of other photopolymerization initiators such as a photoradical polymerization initiator and a photoanion polymerization initiator may be used together with the above-mentioned photocationic polymerization initiator. More than one species may be used in combination.
In this case, the wavelength of light for activating the photo-radical polymerization initiator or the photo-anionic polymerization initiator does not necessarily need to be equal to the wavelength of light for activating the photo-cationic polymerization initiator.

The light for activating the photocationic polymerization initiator includes, for example, infrared rays, visible rays, ultraviolet rays,
X-rays, α-rays, β-rays, γ-rays, electron beams, and the like can be mentioned. Among them, light having a wavelength of ultraviolet light or more, which is highly safe and advantageous in cost, is preferably used, and is particularly preferably used. Is a wavelength 2 that is easy to handle, simple and has a high energy content.
It is an ultraviolet ray of 00 to 400 nm.

Examples of the light source for generating the ultraviolet rays include a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a chemical lamp, a xenon lamp, and the like. Just take the method.

The adhesive composition according to the present invention has a storage elastic modulus at 23 ° C. of 0.9 × 1 in the dynamic viscoelastic spectrum.
0 ⁶ Pa is required to be less, preferably 1.
It is 0 × 10 ^{4 to} 0.9 × 10 ⁶ Pa.

The above storage elastic modulus at 23 ° C. is 0.9 × 10 ⁶
If it exceeds Pa, the flexibility at room temperature becomes insufficient, and the adhesiveness and adhesion to an adherend, the conformability to irregularities may be reduced. If it is less than 1.0 × 10 ⁴ Pa, the room temperature May become too high, causing protrusion and contamination of the surroundings.

The adhesive composition according to the present invention must have a storage elastic modulus at 23 ° C. after curing in the dynamic viscoelastic spectrum of not less than 4.0 × 10 ⁶ Pa, preferably It is 4.0 × 10 ^{6 to} 1.0 × 10 ¹⁰ Pa.

The storage elastic modulus at 23 ° C. after curing is 4.0.
When the pressure is less than × 10 ⁶ Pa, the cohesive strength becomes insufficient, and the shear adhesive strength may decrease. When the pressure exceeds 1.0 × 10 ¹⁰ Pa, the cured product becomes too hard, and the impact resistance and the deformation are reduced. Followability, cold resistance, etc. may be reduced.

The adhesive composition according to the present invention may contain, if necessary, other than the essential components such as the adhesive polymer, the cationically polymerizable compound, and the cationic photopolymerization initiator within a range that does not impair the achievement of the object of the present invention. , Tackifiers, fillers, extenders, thixotropic agents, softeners, plasticizers, stabilizers, antioxidants, crosslinking agents, crosslinking aids, flame retardants, antistatic agents, colorants, organic solvents, etc. One or more of various additives may be added.

The method for producing the adhesive composition according to the present invention is not particularly limited, and may be performed at room temperature or at room temperature using a mixer such as a homodisper, a homomixer, a universal mixer, a planetarium mixer, a kneader, or a three-roll machine. Under heating, a predetermined amount of each of the essential components of the adhesive polymer, the cationically polymerizable compound, and the cationic photopolymerization initiator, and one or more predetermined amounts of one or more of the various additives to be added as necessary. By mixing uniformly, a desired adhesive composition can be obtained.

The thus obtained adhesive composition of the present invention is applied as it is to one or both surfaces of the adherend, and irradiated with light before or after lamination of the adherend. Photocation polymerization may be carried out and cured, but in order to reduce the influence on the adherend and obtain better handling workability and simplicity, the adhesive composition is applied to at least one surface of the support in advance. It is preferably used in the form of a cured adhesive sheet (hereinafter simply referred to as “adhesive sheet”) laminated and processed into a sheet. In addition, the support referred to here is not only a support generally used as a base material of a normal adhesive tape such as cellophane or kraft paper, but also a release film usually used as a separator or Release paper and the like are also included.

The adhesive sheet of the present invention may be a single-sided adhesive sheet, a double-sided adhesive sheet, or a support type adhesive sheet. ,
A non-support type adhesive sheet may be used. If the adhesive composition is applied to the non-release surface of the support, it becomes a support type adhesive sheet.If the adhesive composition is applied to the release surface of the support, it becomes a non-support type. It becomes an adhesive sheet.

The method for producing the adhesive sheet is not particularly limited. For example, a roll-coating method, a gravure coating method, a casting coating method,
A direct coating method in which a pressure-sensitive adhesive composition is applied by various coating methods such as a calendar coating method and an extrusion coating method, and a drying step and a cooling step are performed as necessary to obtain a pressure-sensitive adhesive sheet, After applying a pressure-sensitive adhesive composition to the release surface of the film or release paper by the above-described various coating methods, passing through a drying step or a cooling step as necessary, laminating the pressure-sensitive adhesive sheet on the support surface to form a pressure-sensitive adhesive sheet. Depending on the transfer method to be obtained, a desired adhesive sheet can be obtained.

Examples of the support include various kinds of sheet-like materials such as a plastic film such as a polyethylene terephthalate (PET) film, metal foil, paper, cloth, and non-woven fabric. Can be used for These supports may be subjected to a surface treatment such as a release treatment, a surface oxidation treatment such as a corona treatment, an easy adhesion treatment such as a primer coating, an embossing process, a friction processing, a printing, and a vapor deposition, as necessary. Thereby, it becomes possible to obtain an adhesive sheet having various characteristics. For example, by protecting the surface of the adhesive composition with a plastic film that has been subjected to a release treatment with a silicone-based or non-silicone-based release agent, an adhesive sheet excellent in shape processing such as cutting and punching. Can be obtained.

The thickness of the adhesive sheet thus obtained is
Although not particularly limited, generally 2 μm to 1 μm
mm. The thickness of the adhesive sheet is 2μ
If it is less than m, the adhesive strength may be insufficient, and if it is more than 1 mm, it may take a long time for curing and the productivity may be reduced.

The adhesive sheet of the present invention can be used for an IC card or I
Although it is preferably used for bonding D tags, it can be used not only as an adhesive sheet but also as a film substitute sheet when manufacturing IC cards and ID tags.

That is, the antenna coil and the module are temporarily bonded on the adhesive sheet of the present invention, and another adhesive sheet is laminated on the adhesive sheet and press-molded to form a conventional film. Without the use of materials, I
C cards and ID tags can be manufactured. Of course, a film material may be used in combination as needed.

At this time, the light irradiation may be performed before the lamination or after the lamination. By adopting a method of irradiating light before lamination, an opaque adherend can be bonded without heating, which is convenient for bonding an opaque adherent having low heat resistance.

The bonding is performed by pressure bonding such as roll lamination, pressing, and finger pressure. The adhesive composition and the adhesive sheet of the present invention have excellent tackiness (tack) at ordinary temperature.
, It can be easily bonded by the above-mentioned crimping method.

The adhesive composition and the adhesive sheet of the present invention have a storage elastic modulus at 23 ° C. before curing in a dynamic viscoelastic spectrum of not more than a specific value, and therefore have excellent tackiness at ordinary temperature. (Tack), initial adhesive strength, irregularity followability, and the like. In addition, since the storage elastic modulus at 23 ° C. after curing is set to a specific value or more, excellent adhesive strength, impact resistance, deformation followability, and the like are exhibited after curing. Further, by forming the sheet, it is possible to prevent protrusion during the bonding operation, contamination of the surroundings, and the like, so that the workability and simplicity are excellent.

[0060]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight”.

Example 1 (1) Preparation of Curable Adhesive Composition Polyester resin having a hydroxyl group content of 4 mgKOH / g (trade name “Vylon GSX16”;
70 parts, manufactured by Toyobo Co., Ltd., as a cationically polymerizable compound,
20 parts of liquid bisphenol A type epoxy resin (trade name “Epicoat 828”, manufactured by Yuka Shell Epoxy) and liquid alicyclic flexible epoxy resin (trade name “CELLOXIDE 2”)
081 "(manufactured by Daicel Chemical Industries, Ltd.), 10 parts of an aromatic sulfonium salt (trade name" Optomer SP170 ", manufactured by Asahi Denka Kogyo KK) and 100 parts of methyl ethyl ketone (MEK) as an organic solvent. The mixture was uniformly stirred and mixed using a disper type stirring mixer to prepare a curable adhesive composition.

(2) Preparation of Curable Adhesive Sheet A 50 μm-thick PET film having one surface subjected to silicone release treatment was used as a separator (support), and the release surface of the PET film was treated using a roll coater. Is applied so that the coating thickness after drying is 50 μm, and dried in a gear oven at 110 ° C. for 3 minutes to obtain a curable adhesive sheet. Produced.

(3) Measurement of Storage Elastic Modulus The storage elastic modulus (23 ° C.) of the obtained curable adhesive sheet before and after curing was measured at a frequency of 10 Hz using a dynamic viscoelastic spectrum tester. Was the result. The cured measurement sample was irradiated with ultraviolet rays having a central wavelength of 365 nm at an irradiation intensity of 55 mW / cm ² for 20 seconds using a metal halide lamp (trade name “Handy UV800”, manufactured by Oak Manufacturing Co., Ltd.). And left in an atmosphere of 50 ° C. for 3 days.

(4) Evaluation The performance (shear adhesive strength,
Peeling adhesive strength and irregularity followability) were evaluated by the following methods.
The results are shown in Table 1. The evaluation was performed in an atmosphere at 23 ° C.

Shear adhesive strength: The adhesive surface of the adhesive sheet cut into 1 cm square was adhered to one SUS304. Next, through a PET film as a separator, ultraviolet irradiation was performed under the same conditions as in the case of the storage elastic modulus measurement, and after one minute, the PET film was peeled off, and the other SU
S304 was attached by a shearing method. Then, after press-compression bonding was performed using a press machine under the conditions of a temperature of 23 ° C., a pressure of 5 kg / cm ² and a time of 20 seconds, it was left in an atmosphere of 50 ° C. for 3 days. Thereafter, using an autograph (manufactured by Shimadzu Corporation), the shear adhesive force (M
Pa) was measured.

Peeling adhesive strength: The adhesive surface of the adhesive sheet cut into a width of 1 cm and a length of 5 cm has a wetting tension of 54 dy.
The film was affixed to a corona-treated surface of a 50 μm-thick PET film that had been corona-treated so as to have a thickness of n / cm. Next, ultraviolet light was irradiated through the PET film as a separator under the same conditions as in the above case, and after one minute, the PET film was peeled off, and a hard PVC plate was adhered by a peeling method.
Then, using a laminating machine, at a temperature of 23 ° C. and a linear pressure of 2 k
After laminating under the conditions of g / cm and a laminating speed of 1 m / min, the laminate was left in an atmosphere of 50 ° C. for 3 days. Then, using a strograph (manufactured by Toyo Kikai Seisaku-sho, Ltd.), 180 ° angle peeling adhesive force (N / cm) at a pulling speed of 50 mm / min.
Was measured.

Conformity following property: A 12-μm-thick PET film cut into a 10-mm square is sandwiched between two adhesive-adhesive sheets cut into a 150-mm square, and the PET film as a separator is passed through. UV irradiation is performed under the same conditions as in the above case, and after one minute, lamination is performed under the same conditions as in the case of using a laminating machine, and the curable adhesive sheet / PET film (12 μm thick) / curable adhesive A laminated body of the arrival sheet was obtained. Then, three minutes later, mirror surfaces SUS were applied to both surfaces of the laminate, and the temperature was adjusted to 2 using a press machine.
After press-bonding under conditions of 3 ° C., pressure of 3 kg / cm ² and time of 30 seconds, the mirror surface SUS and the PET film as a separator were removed, and the presence or absence of irregularities of the PET film (12 μm) was visually observed from the surface of the laminate. And the following criterion was used to evaluate the irregularity followability. [Judgment criteria] ○ ‥‥ No unevenness was observed × ‥‥ Embossed unevenness was observed

(Examples 2 and 3 and Comparative Examples 1 to 3) The curable adhesive composition was set in the same manner as in Example 1 except that the composition shown in Table 1 was used. A cured product and a curable adhesive sheet were obtained.

The storage elastic modulus before and after curing of the curable adhesive sheets obtained in Examples 2 and 3 and Comparative Examples 1 to 3 was measured in Example 1.
The measurement was carried out in the same manner as in the above case. The results are shown in Table 1. However, since the adhesive sheet of Comparative Example 2 to which no cationically polymerizable compound was added was not subjected to photocuring by irradiation with ultraviolet rays, only the storage modulus before curing was measured.

Further, the performances (shear adhesive force, peel adhesive force, irregularity followability) of the curable adhesive sheets obtained in Examples 2 and 3 and Comparative Examples 1 to 3 were the same as in Example 1. Was evaluated. The results are shown in Table 1. However, the adhesive sheet of Comparative Example 2 to which no cationically polymerizable compound was added was not subjected to photocuring by ultraviolet irradiation.

[0071]

[Table 1]

As is clear from Table 1, the curable adhesive sheets of Examples 1 to 3 prepared using the curable adhesive compositions of Examples 1 to 3 according to the present invention were all used. It was excellent in all of the shear adhesive force, peel adhesive force and irregularity followability.

On the other hand, the curable pressure-sensitive adhesive sheet of Comparative Example 1 in which the storage elastic modulus at 23 ° C. in the dynamic viscoelastic spectrum exceeded 0.9 × 10 ⁶ Pa was inferior in irregularity followability. In addition, the curable adhesive sheet of Comparative Example 2 in which no cationically polymerizable compound was added, and thus no photocuring was performed,
There was no increase in the elastic modulus and the shear adhesive strength was low. Furthermore, the adhesive polymer does not contain a hydroxyl group, and the storage elastic modulus at 23 ° C. after curing in the dynamic viscoelastic spectrum is 4.0 ×.
The curable pressure-sensitive adhesive sheet of Comparative Example 3, which was less than 10 ⁶ Pa, was inferior in both the shear adhesive force and the peel adhesive force.

[0074]

As described above, the curable pressure-sensitive adhesive composition and the curable pressure-sensitive adhesive sheet according to the present invention have excellent tackiness (tack), initial tackiness, and conformity to irregularities at room temperature before curing. It has excellent adhesive strength (shear adhesive strength and peel adhesive strength) and deformation followability after curing by light irradiation, so it has excellent handling workability and simplicity like adhesives. It has both excellent adhesive properties such as an agent and is suitably used for applications requiring a high degree of reliability, such as bonding of IC cards and ID tags. Further, by forming a sheet, it is possible to prevent protrusion during the bonding operation and contamination of the surroundings and the like, so that the workability is excellent.

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Claims (3)

[Claims] 1. An adhesive polymer having a hydroxyl group content of 0.5 mg KOH / g or more, a cationic polymerizable compound excluding the adhesive polymer and a cationic photopolymerization initiator, and a storage elastic modulus at 23 ° C. in a dynamic viscoelasticity spectrum. Is 0.9
× 10 ⁶ Pa or less and adhesive and pressure-sensitive adhesive composition 23 ° C. storage elastic modulus after curing is equal to or is 4.0 × 10 ⁶ Pa or more. 2. The curable adhesive composition according to claim 1, wherein the adhesive polymer is at least one selected from a polyester polymer, a polyurethane polymer and a polyether polymer. 3. A curable adhesive sheet comprising the support and the curable adhesive composition according to claim 1 laminated on at least one surface of the support.