JP6820705B2 - Adhesive sheets, display bodies and their manufacturing methods - Google Patents

Description

The present invention relates to an adhesive sheet for laminating display body constituent members, a display body formed by laminating display body constituent members, and a method for manufacturing the same.

In recent years, various mobile electronic devices such as mobile phones, smartphones, and tablet terminals have display bodies (displays) using display body modules having liquid crystal elements, light emitting diodes (LED elements), organic electroluminescence (organic EL) elements, and the like. I have.

In such a display, a protective panel is usually provided on the surface side of the display module. A gap is provided between the protective panel and the display module so that the deformed protective panel does not collide with the display module even when the protective panel is deformed by an external force.

However, in the presence of the above-mentioned voids, that is, the air layer, the light reflection loss due to the difference in the refractive index between the protective panel and the air layer and the difference in the refractive index between the air layer and the display module is large, and the display There is a problem that the image quality is deteriorated.

Therefore, it has been proposed to improve the image quality of the display by filling the gap between the protective panel and the display module with an adhesive layer. However, a frame-shaped print layer may exist as a step on the display module side of the protective panel. If the pressure-sensitive adhesive layer does not follow the step, the pressure-sensitive adhesive layer floats in the vicinity of the step, which causes a loss of light reflection. Therefore, the pressure-sensitive adhesive layer is required to have stress relaxation properties that can follow the step.

On the other hand, when the degree of cross-linking of the pressure-sensitive adhesive is relaxed in order to enhance the stress relaxation property of the pressure-sensitive adhesive layer, the cohesive force is reduced. As a result, in the above-mentioned display, when high temperature and high humidity conditions are applied, air bubbles are generated in the adhesive layer near the step, and outgas is generated from the plastic plate which is the protective panel to form the adhesive layer. Blister such as air bubbles, floating, and peeling may occur.

Here, Patent Document 1 describes an acrylic polymer A composed of an acrylic acid alkoxyalkyl ester as an essential monomer component, a (meth) acrylic acid ester having a cyclic structure in the molecule, and a linear or branched alkyl. A composition containing an acrylic polymer B composed of a (meth) acrylic acid alkyl ester having a group as an essential monomer component is cured by irradiation with active energy rays, and the pressure is 23 ° C. and the strain is 300%. Discloses an optical double-sided pressure-sensitive adhesive sheet having an pressure-sensitive adhesive layer having a residual stress of 3.0 N / cm ² or less after 180 seconds measured by the tensile stress relaxation test of.

Japanese Unexamined Patent Publication No. 2013-6892

In the double-sided adhesive sheet for optics in Patent Document 1, the step followability and blister resistance are improved by reducing the residual stress of the adhesive layer at the stage of the pressure-sensitive adhesive sheet (the stage before being bonded to the adherend). I'm trying to make you. Further, the double-sided optical adhesive sheet in Patent Document 1 is a pressure-sensitive adhesive layer cured by irradiation with active energy rays at the stage of the adhesive sheet.

However, even in the double-sided adhesive sheet for optics in Patent Document 1, it is not possible to exceed the framework of balancing the stress relaxation property and the degree of cross-linking described above, and therefore, both the step followability and the blister resistance are still satisfied. It wasn't a good thing.

INDUSTRIAL APPLICABILITY The present invention is an adhesive sheet that can relieve stress during bonding, has high film strength, and is excellent in both step followability and blister resistance, and is excellent in both step followability and blister resistance. It is an object of the present invention to provide display bodies and methods for producing them.

In order to achieve the above object, first, the present invention is an adhesive sheet provided with an adhesive layer for adhering one display body constituent member and another display body constituent member, and the adhesive. Provided is a pressure-sensitive adhesive sheet, wherein the agent layer comprises an active energy ray-curable pressure-sensitive adhesive containing a polyrotaxane compound (Invention 1).

In the above invention (Invention 1), since the pressure-sensitive adhesive layer contains a polyrotaxane compound and is not yet cured by active energy rays and has a relatively low elastic modulus, stress at the time of bonding can be relaxed. , Excellent in initial step followability. Further, by curing the pressure-sensitive adhesive layer with active energy rays after bonding, the film strength is improved, and both the step followability and the blister resistance under high temperature and high humidity conditions are excellent.

In the above invention (Invention 1), the gel fraction of the pressure-sensitive adhesive is preferably 30% or more and 70% or less (Invention 2).

In the above inventions (Inventions 1 and 2), the pressure-sensitive adhesive layer has a cross-linked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal cross-linking agent (B), and has an active energy ray. It is preferably composed of an active energy ray-curable pressure-sensitive adhesive containing a curable component (C) and a polyrotaxane compound (D) (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the one display body constituent member has at least a step on the surface on the side to be bonded (Invention 4).

In the above inventions (Inventions 1 to 4), the pressure-sensitive adhesive sheet includes two release sheets, and the pressure-sensitive adhesive layer is sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. (Invention 5).

Secondly, the present invention is a method for producing an adhesive sheet provided with an adhesive layer for adhering one display body constituent member and another display body constituent member, together with a (meth) acrylic acid ester. By applying an adhesive composition containing a polymer (A), a heat-crosslinking agent (B), an active energy ray-curable component (C), and a polyrotaxane compound (D), and then heat-crosslinking, Provided is a method for producing an adhesive sheet, which comprises forming an active energy ray-curable pressure-sensitive adhesive layer (Invention 6).

Thirdly, the present invention provides a cured pressure-sensitive adhesive layer for bonding one display body component, another display body component, and the one display body component and the other display body component to each other. The cured pressure-sensitive adhesive layer has a cross-linked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal cross-linking agent (B), and an active energy ray. Provided is a display body comprising a cured product of a curable component (C) and a pressure-sensitive adhesive containing a polyrotaxane compound (D) (Invention 7).

In the above invention (Invention 7), the gel fraction of the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is preferably 50% or more and 90% or less (Invention 8).

In the above inventions (Inventions 7 and 8), the total light transmittance of the cured pressure-sensitive adhesive layer is preferably 90% or more (Invention 9).

In the above inventions (Inventions 7 to 9), the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is molded into a thickness of 500 μm, a width of 10 mm, and a length of 75 mm, the measurement range is 20 mm in length, and the temperature is 23 ° C. and 50% RH. Based on the maximum stress value measured by performing a tensile test of 150% elongation at a rate of 200 mm / min and the stress value 60 seconds after the start of measurement, the stress relaxation rate represented by the following formula is 45. It is preferably% or more and 99% or less (Invention 10).
Stress relaxation rate (%) = {(maximum stress value-stress value 60 seconds after the start of measurement) / maximum stress value} x 100

In the above invention (Inventions 7 to 10), the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is molded into a thickness of 500 μm, a width of 10 mm, and a length of 75 mm, the measurement range is 20 mm in length, and the temperature is 23 ° C. and 50% RH. The maximum stress value measured by performing a tensile test of stretching 150% at a rate of 200 mm / min in the above environment is preferably 0.01 N or more and 3 N or less (Invention 11).

Fourth, the present invention prepares a laminated body formed by laminating one display body component and another display body component via an adhesive layer of the pressure-sensitive adhesive sheet (Invention 1 to 5). Provided is a method for producing a display body, which comprises irradiating the pressure-sensitive adhesive layer of the laminated body with active energy rays and curing the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer after curing (Invention 12). ..

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to the present invention can relieve stress at the time of bonding and can reinforce the film strength after bonding, and is therefore excellent in both step followability and blister resistance. Further, the display body according to the present invention is excellent in both step-following property and blister resistance due to the pressure-sensitive adhesive layer having excellent film strength and stress relaxation property. Further, according to the method according to the present invention, the adhesive sheet and the display body can be manufactured.

It is sectional drawing of the adhesive sheet which concerns on one Embodiment of this invention. It is sectional drawing which shows one structural example of the display body (touch panel) which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Adhesive sheet]
The pressure-sensitive adhesive sheet according to the present embodiment is a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer for adhering one display body component and another display body component. The display body and the display body constituent members will be described later.

As shown in FIG. 1, the adhesive sheet 1 according to the present embodiment as an example is in contact with the two release sheets 12a and 12b and the release surfaces of the two release sheets 12a and 12b. It is composed of an adhesive layer 11 sandwiched between the release sheets 12a and 12b. The peeling surface of the release sheet in the present specification means a surface of the release sheet that has peelability, and includes both a surface that has been peeled and a surface that exhibits peelability without peeling. ..

1. 1. Adhesive layer The adhesive layer 11 is made of an active energy ray-curable pressure-sensitive adhesive containing a polyrotaxane compound, and has not yet been cured by the active energy rays. The polyrotaxane compound has a mechanical bond between the cyclic molecule and the linear molecule penetrating the cyclic molecule, and the cyclic molecule can freely move on the linear molecule. Due to this structure, the polyrotaxane compound can impart excellent stress relaxation property to the obtained pressure-sensitive adhesive. Since the pressure-sensitive adhesive layer 11 contains such a polyrotaxane compound and has not yet been cured by active energy rays and has a relatively low elastic modulus, it is attached to a display body component which is an adherend. It is possible to relieve the stress that sometimes occurs. Therefore, even when the pressure-sensitive adhesive sheet 1 is attached to the display body constituent member having a step, the pressure-sensitive adhesive layer 11 easily follows the step, and it is possible to prevent gaps, floats, and the like from occurring in the vicinity of the step. Further, since stress is unlikely to remain inside the pressure-sensitive adhesive layer 11 bonded to the display body constituent member, bending of the display body constituent member due to the stress can be suppressed.

On the other hand, when the pressure-sensitive adhesive sheet 1 according to the present embodiment is used, one display body component member is bonded to another display body component member by the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1, and then one display body component member is used. Alternatively, the pressure-sensitive adhesive layer 11 is irradiated with active energy rays via another display body component to cure the pressure-sensitive adhesive layer 11 and the pressure-sensitive adhesive layer (in FIG. 2, which will be described later, the pressure-sensitive adhesive layer 11). '). This cured adhesive layer has stress relaxation properties due to the polyrotaxane compound, and the film strength is improved by curing. Therefore, the obtained laminate (display body) is subjected to high temperature and high humidity conditions, for example, 85 ° C. Even when the product is left under the condition of 85% RH for 72 hours, the generation of bubbles, floats, peeling, etc. in the vicinity of the step is suppressed. Further, the generation of blisters such as air bubbles, floating, and peeling at the interface between the display body component and the cured adhesive layer is suppressed.

That is, the pressure-sensitive adhesive sheet 1 according to the present embodiment can relieve stress at the time of bonding and can reinforce the film strength after bonding, and thus has an initial step followability and a high temperature. It is excellent in step followability and blister resistance under high humidity conditions, and can suppress bending of display body constituent members.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 11 is an active energy ray-curable pressure-sensitive adhesive containing a polyrotaxane compound as described above, and the type thereof is not particularly limited as long as the above-mentioned effects are exhibited. The pressure-sensitive adhesive may be, for example, any of an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a polyester-based pressure-sensitive adhesive, a polyvinyl ether-based pressure-sensitive adhesive, and the like. Further, the pressure-sensitive adhesive may be an emulsion type, a solvent type or a solvent-free type, and may be either a crosslinked type or a non-crosslinked type. Among these, acrylic pressure-sensitive adhesives that easily exhibit adhesive strength and optical properties suitable for optical applications are preferable, and solvent-type and cross-linking type acrylic pressure-sensitive adhesives are particularly preferable.

The pressure-sensitive adhesive layer 11 has a cross-linked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal cross-linking agent (B), and also has an active energy ray-curable component (C) and a polyrotaxane compound. It is preferably made of an active energy ray-curable pressure-sensitive adhesive containing (D). In other words, the pressure-sensitive adhesive layer 11 contains a (meth) acrylic acid ester copolymer (A), a heat-crosslinking agent (B), an active energy ray-curable component (C), and a polyrotaxane compound (D). It is preferably composed of an active energy ray-curable pressure-sensitive adhesive obtained by thermally cross-linking the contained pressure-sensitive adhesive composition (hereinafter, may be referred to as "sticky composition P"). In the pressure-sensitive adhesive layer 11, the polyrotaxane compound (D) may react with the thermal cross-linking agent (B) and be incorporated into the above-mentioned cross-linking structure. Here, in the present specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

In the pressure-sensitive adhesive obtained by heat-crosslinking the pressure-sensitive adhesive composition P, the active energy ray-curable component (C) has not yet been cured and is contained in the pressure-sensitive adhesive as it is blended in the pressure-sensitive adhesive composition P. Exists. This active energy ray-curable component (C) polymerizes and cures when the pressure-sensitive adhesive layer 11 is irradiated with active energy rays when the pressure-sensitive adhesive sheet 1 is used (after the adherends are attached). ..

Since the pressure-sensitive adhesive obtained by thermally cross-linking the pressure-sensitive adhesive composition P contains the polyrotaxane compound (D), it has excellent stress relaxation properties even if a sufficient cross-linked structure is constructed. Therefore, the film strength of the pressure-sensitive adhesive layer 11 can be made relatively high. Therefore, for example, when the pressure-sensitive adhesive sheet is cut or the like, problems such as adhesion of the pressure-sensitive adhesive to the blade are suppressed, and the cutting suitability is excellent. In addition, it is possible to prevent the pressure-sensitive adhesive from seeping out from the pressure-sensitive adhesive layer 11 during storage of the pressure-sensitive adhesive sheet 1.
Hereinafter, the pressure-sensitive adhesive obtained by thermally cross-linking the pressure-sensitive adhesive composition P will be described in detail.

(1) Each component (1-1) (meth) acrylic acid ester copolymer (A)
The (meth) acrylic acid ester copolymer (A) may contain a reactive group-containing monomer having a reactive group in the molecule that reacts with the thermal cross-linking agent (B) as a monomer unit constituting the polymer. preferable. The reactive group derived from the reactive group-containing monomer reacts with the thermal cross-linking agent (B) to form a cross-linked structure (three-dimensional network structure), and a pressure-sensitive adhesive layer 11 having a relatively high film strength can be obtained.

Examples of the reactive group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxy group in the molecule (carboxy group-containing monomer), and a monomer having an amino group in the molecule (amino group-containing monomer). ) Etc. are preferably mentioned. Among these, a hydroxyl group-containing monomer having excellent reactivity with the thermal cross-linking agent (B) and having little adverse effect on the adherend is particularly preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth). ) Hydroxyalkyl esters of (meth) acrylic acid such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylic acid can be mentioned. Among them, (meth) acrylic acid 2-in the obtained (meth) acrylic acid ester copolymer (A) from the viewpoint of reactivity of the hydroxyl group with the thermal cross-linking agent (B) and copolymerizability with other monomers. Hydroxyethyl and 4-hydroxybutyl (meth) acrylate are preferred, with 2-hydroxyethyl (meth) acrylate being particularly preferred. These may be used alone or in combination of two or more.

Examples of the carboxy group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Of these, acrylic acid is preferable from the viewpoint of the reactivity of the carboxy group with the thermal cross-linking agent (B) in the obtained (meth) acrylic acid ester copolymer (A) and the copolymerizability with other monomers. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, n-butylaminoethyl (meth) acrylate and the like. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) preferably contains a reactive group-containing monomer as a lower limit value of 1% by mass or more, particularly 6% by mass or more, as a monomer unit constituting the polymer. It is preferable that the content is 12% by mass or more. Further, the (meth) acrylic acid ester copolymer (A) preferably contains a reactive group-containing monomer as an upper limit value of 50% by mass or less, particularly 40% by mass, as a monomer unit constituting the polymer. It is preferably contained below, and more preferably 30% by mass or less. When the (meth) acrylic acid ester copolymer (A) contains a reactive group-containing monomer in the above amount as a monomer unit, a good crosslinked structure is formed in the obtained pressure-sensitive adhesive, and the pressure-sensitive adhesive having a relatively high film strength. Layer 11 is obtained. Further, when the content of the reactive group-containing monomer is 12% by mass or more, a predetermined amount of the reactive group remains in the pressure-sensitive adhesive. The reactive group is a hydrophilic group, and when such a hydrophilic group is present in a predetermined amount of the pressure-sensitive adhesive, even if the pressure-sensitive adhesive is placed under high-temperature and high-humidity conditions, the pressure-sensitive adhesive under the high-temperature and high-humidity conditions. It has good compatibility with the moisture infiltrated into the adhesive, and as a result, whitening of the adhesive when returned to normal temperature and humidity is suppressed (excellent in moisture-heat whitening resistance).

On the other hand, it is also preferable that the (meth) acrylic acid ester copolymer (A) does not contain a carboxy group-containing monomer as a monomer unit constituting the polymer. Since the carboxy group is an acid component, since the carboxy group-containing monomer is not contained, a transparent conductive film such as tin-doped indium oxide (ITO) or a metal film, which causes a problem due to the acid, is attached to the adhesive. Even if it exists, those defects (corrosion, change in resistance value, etc.) due to acid can be suppressed. However, it is permissible to contain a predetermined amount of the carboxy group-containing monomer so as not to cause such a problem. Specifically, in the (meth) acrylic acid ester copolymer (A), as a monomer unit, a carboxy group-containing monomer is contained in an amount of less than 5% by mass, preferably 2% by mass or less, and particularly preferably 0.1% by mass or less. It is permissible to contain in the amount of.

The (meth) acrylic acid ester copolymer (A) contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and thus has preferable adhesiveness. Can be expressed. Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, and n- (meth) acrylic acid. Butyl, n-pentyl (meth) acrylic acid, n-hexyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, isooctyl (meth) acrylic acid, n-decyl (meth) acrylic acid, (meth) acrylic acid Examples thereof include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, and stearyl (meth) acrylate. Among them, (meth) acrylic acid ester having 1 to 8 carbon atoms of the alkyl group is preferable, and n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is particularly preferable from the viewpoint of further improving the adhesiveness. , 2-Ethylhexyl (meth) acrylate is more preferred. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) may contain 40% by mass or more of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. It is preferable that the content is particularly preferably 50% by mass or more, and further preferably 60% by mass or more. When the (meth) acrylic acid alkyl ester is contained in an amount of 40% by mass or more, the (meth) acrylic acid ester copolymer (A) can be imparted with suitable adhesiveness. Further, the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group is preferably contained in an amount of 90% by mass or less, particularly preferably 80% by mass or less, and further contained 70% by mass or less. Is preferable. By setting the content of the (meth) acrylic acid alkyl ester to 90% by mass or less, a desired amount of other monomer components can be introduced into the (meth) acrylic acid ester copolymer (A).

It is also preferable that the (meth) acrylic acid ester copolymer (A) contains a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) as a monomer unit constituting the copolymer. Since the alicyclic structure-containing monomer is bulky, it is presumed that the presence of the monomer in the polymer widens the distance between the polymers, and the obtained pressure-sensitive adhesive can be made excellent in flexibility. .. Therefore, the pressure-sensitive adhesive obtained by cross-linking the pressure-sensitive adhesive composition P by using the alicyclic structure-containing monomer as a constituent monomer unit in the (meth) acrylic acid ester copolymer (A) can relax stress at the time of application. It becomes better in sex.

The alicyclic structure carbon ring in the alicyclic structure-containing monomer may have a saturated structure or may have an unsaturated bond as a part. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as two rings or three rings. From the viewpoint of widening the distance between the obtained (meth) acrylic acid ester copolymers (A) and effectively exerting the flexibility of the pressure-sensitive adhesive, the alicyclic structure is a polycyclic alicyclic structure. (Polycyclic structure) is preferable. Further, in consideration of the compatibility between the (meth) acrylic acid ester copolymer (A) and other components, the polycyclic structure is particularly preferably bicyclic to tetracyclic. Further, as described above, from the viewpoint of effectively exerting the flexible action of the pressure-sensitive adhesive, the number of carbon atoms of the alicyclic structure (referring to all the carbon atoms of the portion forming the ring, and a plurality of rings are independent). The total number of carbon atoms (referring to the total number of carbon atoms) is usually preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, but from the viewpoint of compatibility as described above, it is preferably 15 or less, and particularly preferably 10 or less.

Examples of the alicyclic structure include cyclohexyl skeleton, dicyclopentadiene skeleton, adamantan skeleton, isobornyl skeleton, cycloalcan skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononan skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.). , Cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornen skeleton, norbornadien skeleton, Cuban skeleton, Basquetan skeleton, Hausan skeleton, Spiro skeleton, etc., among which it exhibits more excellent durability. Those containing a dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), adamantan skeleton (carbon number of alicyclic structure: 10) or isobornyl skeleton (carbon number of alicyclic structure: 7) are preferable, and particularly Those containing an isobornyl skeleton are preferable.

As the alicyclic structure-containing monomer, a (meth) acrylic acid ester monomer containing the above skeleton is preferable, and specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth). Examples include adamantyl acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, etc. Among them, (meth) acrylic which exhibits more excellent durability. Dicyclopentanyl acid, adamantyl (meth) acrylate or isobornyl (meth) acrylate are preferred, and isobornyl (meth) acrylate is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the (meth) acrylic acid ester copolymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, the (meth) acrylic acid ester copolymer (A) is an alicyclic. The structure-containing monomer is preferably contained in an amount of 5% by mass or more, particularly preferably 8% by mass or more, and further preferably 10% by mass or more. Further, the (meth) acrylic acid ester copolymer (A) preferably contains 40% by mass or less of an alicyclic structure-containing monomer, and particularly 30% by mass or less, as a monomer unit constituting the polymer. It is preferably contained in an amount of 20% by mass or less. When the content of the alicyclic structure-containing monomer is in the above range, the initial step followability of the obtained pressure-sensitive adhesive becomes more excellent.

The (meth) acrylic acid ester copolymer (A) preferably contains a monomer having a nitrogen atom in the molecule (nitrogen atom-containing monomer) as a monomer unit constituting the copolymer. The amino group-containing monomer exemplified as the reactive group-containing monomer shall be excluded from the nitrogen atom-containing monomer. By allowing the nitrogen atom-containing monomer to be present in the polymer as a constituent unit, the reaction between the acrylic acid ester copolymer (A) and the thermal cross-linking agent (B) can be promoted, or the adhesive can be made polar and adherent. The cohesive force of the agent itself can be enhanced.

Examples of the nitrogen atom-containing monomer include a monomer having a tertiary amino group, a monomer having an amide group, a monomer having a nitrogen-containing heterocycle, and the like, and among them, a monomer having a nitrogen-containing heterocycle is preferable.

Examples of the monomer having a nitrogen-containing heterocycle include N- (meth) acryloylmorpholin, N-vinyl-2-pyrrolidone, N- (meth) acryloylpyrrolidone, N- (meth) acryloylpiperidin, and N- (meth) acryloyl. Pyrrolidin, N- (meth) acryloyl acryloyl, aziridinyl ethyl (meth) acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N- (meth) acryloylmorpholin, which exhibits more excellent adhesive strength, is preferable, and N-acryloylmorpholin is particularly preferable.

Examples of the nitrogen atom-containing monomer other than the above-mentioned monomer having a nitrogen-containing heterocycle include (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-tert-butyl (meth). ) Acrylamide, N, N-dimethyl (meth) acrylamide, N, N-ethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-phenyl (meth) acrylamide , Dimethylaminopropyl (meth) acrylamide, N-vinylcaprolactam, dimethylaminoethyl (meth) acrylate and the like can also be used.
The above nitrogen atom-containing monomers may be used alone or in combination of two or more.

When the (meth) acrylic acid ester copolymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the (meth) acrylic acid ester copolymer (A) is a nitrogen atom-containing monomer. Is preferably contained in an amount of 1% by mass or more, particularly preferably 2% by mass or more, and further preferably 5% by mass or more. Further, the (meth) acrylic acid ester copolymer (A) preferably contains 20% by mass or less of a nitrogen atom-containing monomer, particularly 15% by mass or less, as a monomer unit constituting the polymer. It is preferable, and it is preferable that the content is 10% by mass or less. When the content of the nitrogen atom-containing monomer is within the above range, the cohesive force of the obtained pressure-sensitive adhesive is effectively improved.

If desired, the (meth) acrylic acid ester copolymer (A) may contain another monomer as a monomer unit constituting the polymer. As the other monomer, a monomer containing no reactive functional group is preferable. Examples of such other monomers include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, vinyl acetate, and styrene. These may be used alone or in combination of two or more.

The polymerization mode of the (meth) acrylic acid ester copolymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 100,000 or more as a lower limit value, particularly preferably 200,000 or more, and further preferably 300,000 or more. .. When the lower limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is equal to or higher than the above, the film strength of the obtained pressure-sensitive adhesive becomes higher. The weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 1.2 million or less, particularly preferably 900,000 or less, and further 700,000 or less as the upper limit value. Is preferable. When the upper limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is not more than the above, the step-following property of the obtained pressure-sensitive adhesive becomes more excellent. The weight average molecular weight in the present specification is a standard polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method.

In the adhesive composition P, one type of (meth) acrylic acid ester copolymer (A) may be used alone, or two or more types may be used in combination.

(1-2) Thermal cross-linking agent (B)
When the adhesive composition P containing the heat-crosslinking agent (B) is heated, the heat-crosslinking agent (B) crosslinks the (meth) acrylic acid ester copolymer (A) to form a three-dimensional network structure. As a result, the pressure-sensitive adhesive layer 11 having a relatively high film strength can be obtained.

The thermal cross-linking agent (B) may be any as long as it reacts with the reactive group of the (meth) acrylic acid ester copolymer (A). For example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, or an amine-based cross-linking agent. Crosslinking agent, melamine-based cross-linking agent, aziridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking Agents and the like can be mentioned. Among the above, when the reactive group of the (meth) acrylic acid ester copolymer (A) is a hydroxyl group, it is preferable to use an isocyanate-based cross-linking agent having excellent reactivity with the hydroxyl group, and (meth) acrylic acid. When the reactive group of the ester copolymer (A) is a carboxy group, it is preferable to use an epoxy-based cross-linking agent having excellent reactivity with the carboxy group. The heat cross-linking agent (B) may be used alone or in combination of two or more.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. , And their biurets, isocyanurates, and adducts, which are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Of these, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are preferable, and trimethylolpropane-modified tolylene diisocyanate is further preferable. ..

Examples of the epoxy-based cross-linking agent include 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N, N, N', N'-tetraglycidyl-m-xylylenediamine, and ethylene glycol diglycidyl ether. , 1,6-Hexanediol diglycidyl ether, trimethylpropan diglycidyl ether, diglycidyl aniline, diglycidyl amine and the like. Of these, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane is preferable from the viewpoint of reactivity with a carboxy group.

The content of the heat-crosslinking agent (B) in the adhesive composition P is preferably 0.01 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A), and is 0. It is more preferably 10 parts by mass or more, particularly preferably 0.20 parts by mass or more, and further preferably 0.30 parts by mass or more. Further, the content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 2 parts by mass or less. When the content of the thermal cross-linking agent (B) is in the above range, the obtained pressure-sensitive adhesive exhibits sufficient cohesive force while having sufficient flexibility, and the pressure-sensitive adhesive layer 11 having a relatively high coating strength can be formed. can get.

(1-3) Active energy ray-curable component (C)
The pressure-sensitive adhesive layer 11 formed by the pressure-sensitive adhesive composition P containing the active energy ray-curable component (C) becomes an active energy ray-curable pressure-sensitive adhesive layer. In the pressure-sensitive adhesive layer 11, the active energy ray-curable components (C) are polymerized with each other by curing by irradiation with active energy rays after the adherend is attached, and the polymerized active energy ray-curable components (C) are (meth). ) It is presumed that the acrylic acid ester copolymer (A) is entangled in the crosslinked structure (three-dimensional network structure). Since the pressure-sensitive adhesive having such a high-order structure has high cohesive force and high film strength, it is excellent in step followability and blister resistance under high temperature and high humidity conditions.

The active energy ray-curable component (C) is not particularly limited as long as it is a component that is cured by irradiation with active energy rays and obtains the above effects, and may be any monomer, oligomer or polymer, and they may be used. May be a mixture of. Among them, a polyfunctional acrylate-based monomer having excellent compatibility with the (meth) acrylic acid ester copolymer (A) and the like can be preferably mentioned.

Examples of the polyfunctional acrylate-based monomer include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. , Neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, dicyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified di (meth) acrylate 2 such as meta) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene, etc. Functional type: Trimethylol propanetri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylol propanetri (meth) acrylate ) Acrylate, trifunctional forms such as tris (acryloxyethyl) isocyanurate, ε-caprolactone-modified tris- (2- (meth) acryloxyethyl) isocyanurate; diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) 4-functional type such as acrylate; 5-functional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; 6-functional type such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate Can be mentioned. Among the above, di (acryloxyethyl) isocyanurate, tris (acryloxyethyl) isocyanurate, ε-caprolactone-modified tris from the viewpoint of step followability and blister resistance of the obtained adhesive under high temperature and high humidity conditions. -A polyfunctional acrylate-based monomer having an isocyanurate structure in the molecule such as 2- (2- (meth) acryloxyethyl) isocyanurate is preferable, and a polyfunctional acrylate having a trifunctionality or higher and having an isocyanurate structure in the molecule is preferable. Monomers are more preferred, and ε-caprolactone-modified tris- (2- (meth) acryloxiethyl) isocyanurate is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type. Further, from the viewpoint of compatibility with the (meth) acrylic acid ester copolymer (A), the polyfunctional acrylate-based monomer preferably has a molecular weight of less than 1000.

As the active energy ray-curable component (C), an active energy ray-curable acrylate-based oligomer can also be used. The acrylate-based oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylate-based oligomers include polyester acrylate-based, epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polybutadiene acrylate-based, and silicone acrylate-based.

The weight average molecular weight of the acrylate-based oligomer is preferably 50,000 or less, particularly preferably 1,000 to 50,000, and further preferably 3,000 to 40,000. One of these acrylate-based oligomers may be used alone, or two or more thereof may be used in combination.

Further, as the active energy ray-curable component (C), an adduct acrylate-based polymer in which a group having a (meth) acryloyl group is introduced into a side chain can also be used. Such an adduct acrylate polymer uses a copolymer of a (meth) acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and is used as a part of the crosslinkable functional group of the copolymer. , (Meta) It can be obtained by reacting a compound having a group that reacts with an acryloyl group and a crosslinkable functional group.

The weight average molecular weight of the adduct acrylate polymer is preferably about 50,000 to 900,000, and particularly preferably about 100,000 to 500,000.

As the active energy ray-curable component (C), one type may be selected from the above-mentioned polyfunctional acrylate-based monomer, acrylate-based oligomer and adduct acrylate-based polymer, or two or more types may be used in combination. It can also be used in combination with other active energy ray-curable components.

The content of the active energy ray-curable component (C) in the adhesive composition P is the same as that of the (meth) acrylic acid ester from the viewpoint of improving the cohesive force of the obtained adhesive and making the blister resistance excellent. The lower limit is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and particularly preferably 5 parts by mass or more with respect to 100 parts by mass of the polymer (A). On the other hand, the content should be 50 parts by mass or less as an upper limit from the viewpoint of preventing the active energy ray-curable component (C) from being phase-separated from the (meth) acrylic acid ester copolymer (A). It is more preferably 20 parts by mass or less, and further preferably 10 parts by mass or less from the viewpoint of further improving the stress relaxation property.

(1-4) Polyrotaxane compound (D)
The polyrotaxane compound (D) is a compound in which a linear molecule penetrates through the openings of at least two cyclic molecules and has block groups at both ends of the linear molecule. In this polyrotaxane compound (D), the cyclic molecule can freely move on the linear molecule, but the cyclic molecule has a structure in which the cyclic molecule cannot escape from the linear molecule due to the blocking group. That is, the linear molecule and the cyclic molecule maintain their morphology not by a chemical bond such as a covalent bond but by a so-called mechanical bond. The pressure-sensitive adhesive (tacky composition P) according to the present embodiment contains the polyrotaxane compound (D) having such a mechanical bond, so that the pressure-sensitive adhesive layer 11 obtained is a display body constituent member which is an adherend. The stress generated at the time of bonding can be relaxed, and the stress relaxation property at the time of bonding is excellent. In particular, when the cyclic molecule of the polyrotaxane compound (D) is a cyclic oligosaccharide having a hydroxyl group as a reactive group, the isocyanate-based cross-linking agent is used when the isocyanate-based cross-linking agent is used as the thermal cross-linking agent (B). The (meth) acrylic acid ester copolymer (A) and the polyrotaxane compound (D) (cyclic molecule) are crosslinked with each other, and the cyclic molecule freely moves on the linear molecule in the polyrotaxane compound (D). By doing so, the flexibility as a crosslinked body is remarkably improved. As a result, the obtained pressure-sensitive adhesive becomes more excellent in stress relaxation property at the time of bonding.

The polyrotaxane compound (D) in the present embodiment preferably has a cyclic oligosaccharide as a cyclic molecule. By using a cyclic oligosaccharide as the cyclic molecule of the polyrotaxane compound (D), an appropriate ring diameter can be selected, and thus the effect of the movement of the cyclic molecule on the linear molecule is likely to be exhibited. Further, when the cyclic oligosaccharide has a hydroxyl group as a reactive group, the reaction with the isocyanate-based cross-linking agent is easy. Further, it is easy to introduce various substituents and the like, whereby the compatibility between the polyrotaxane compound (D) and other components can be adjusted by the polyrotaxane compound (D). Further, the cyclic oligosaccharide has an advantage that it is easily available. In addition, in this specification, "cyclic" of "cyclic molecule" or "cyclic oligosaccharide" means substantially "cyclic". That is, the cyclic molecule does not have to be completely ring-closed, and may have a helical structure, for example, as long as it can move on the linear molecule.

Examples of the cyclic oligosaccharide include cyclodextrins such as α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, and α-cyclodextrin is particularly preferable. Two or more kinds of cyclic molecules of the polyrotaxane compound (D) may be mixed in the polyrotaxane compound (D) or in the pressure-sensitive adhesive (adhesive composition P).

When the cyclic molecule (cyclic oligosaccharide) of the polyrotaxane compound (D) has a hydroxyl group as a reactive group, the hydroxyl group may be the hydroxyl group originally possessed by the cyclic oligosaccharide (meaning the state before modification). However, it may be a hydroxyl group introduced as a substituent into the cyclic oligosaccharide.

The hydroxyl value of the cyclic molecule is preferably 10 mgKOH / g or more, more preferably 30 mgKOH / g or more, and particularly preferably 50 mgKOH / g or more as the lower limit value. When the lower limit of the hydroxyl value is equal to or higher than the above, the polyrotaxane compound (D) can sufficiently react with the isocyanate-based cross-linking agent. The hydroxyl value of the cyclic molecule is preferably 1000 mgKOH / g or less, more preferably 200 mgKOH / g or less, and particularly preferably 100 mgKOH / g or less as the upper limit value. When the upper limit of the hydroxyl value exceeds the above value, a large number of crosslinks occur in the same cyclic molecule, so that the cyclic molecule itself becomes a crosslink point, and the effect of the crosslink point of the polyrotaxane compound (D) as a whole can be exhibited. As a result, sufficient stress relaxation property of the pressure-sensitive adhesive layer may not be ensured.

The linear molecule of the polyrotaxane compound (D) is a molecule or substance that is encapsulated in a cyclic molecule and can be integrated by a mechanical bond rather than a chemical bond such as a covalent bond, and is linear. If so, there is no particular limitation. In addition, in this specification, "straight line" of "linear molecule" means that it is substantially "straight line". That is, the linear molecule may have a branched chain as long as the cyclic molecule can move on the linear molecule.

As the linear molecule of the polyrotaxane compound (D), for example, polyethylene glycol, polypropylene glycol, polyisoprene, polyisobutylene, polybutadiene, polytetrahydrofuran, polyacrylic acid ester, polydimethylsiloxane, polyethylene, polypropylene and the like are preferable. Two or more kinds of linear molecules may be mixed in the adhesive composition P.

The number average molecular weight of the linear molecules of the polyrotaxane compound (D) is preferably 3,000 or more, particularly preferably 10,000 or more, and further preferably 20,000 or more as the lower limit value. preferable. When the lower limit of the number average molecular weight is equal to or higher than the above, the amount of movement of the cyclic molecule on the linear molecule is secured, and the stress relaxation property of the pressure-sensitive adhesive can be sufficiently obtained. The number average molecular weight of the linear molecules of the polyrotaxane compound (D) is preferably 300,000 or less as an upper limit value, particularly preferably 200,000 or less, and further preferably 100,000 or less. Is preferable. When the upper limit of the number average molecular weight is not more than the above, the solubility of the polyrotaxane compound (D) in a solvent and the compatibility with the (meth) acrylic acid ester copolymer (A) are improved.

The blocking group of the polyrotaxane compound (D) is not particularly limited as long as it is a group capable of retaining the skewered form of the cyclic molecule by the linear molecule. Examples of such a group include a bulky group and an ionic group.

Specifically, the blocking group of the polyrotaxane compound (D) is a dinitrophenyl group, a cyclodextrin group, an adamantan group, a trityl group group, a fluorescein group, a pyrene group, an anthracene group, etc., or a number average molecular weight of 1,000. The main chain or side chain of a polymer of ~ 1,000,000 is preferable, and two or more of these blocking groups may be mixed in the polyrotaxane compound (D) or in the adhesive composition P.

The polyrotaxane compound (D) described above can be obtained by a conventionally known method (for example, the method described in JP-A-2005-154675).

The content of the polyrotaxane compound (D) in the adhesive composition P according to the present embodiment is 0.1 part by mass or more as a lower limit value with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). It is preferable that the amount is 1 part by mass or more, and further preferably 5 parts by mass or more. When the content of the polyrotaxane compound (D) is 0.1 part by mass or more, the stress relaxation property of the obtained pressure-sensitive adhesive layer 11 at the time of bonding becomes more excellent. The content of the polyrotaxane compound (D) is preferably 50 parts by mass or less, more preferably 25 parts by mass or less, and particularly preferably 10 parts by mass or less as an upper limit value. When the content of the polyrotaxane compound (D) is 50 parts by mass or less, the total light transmittance of the adhesive layer 11'after curing can be maintained high, which is suitable for optical applications.

(1-5) Photopolymerization Initiator (E)
When ultraviolet rays are used as the active energy rays to irradiate the pressure-sensitive adhesive layer 11, the pressure-sensitive adhesive composition P preferably further contains a photopolymerization initiator (E). By containing the photopolymerization initiator (E) in this way, the active energy ray-curable component (C) can be efficiently polymerized, and the polymerization curing time and the irradiation amount of the active energy rays can be reduced. it can.

Examples of such a photopolymerization initiator (E) include benzoine, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, and 2,2-dimethoxy. -2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylamino Benzophenone, Dichlorobenzophenone, 2-Methylanthraquinone, 2-Ethylanthraquinone, 2-Turrary-butylanthraquinone, 2-Aminoanthraquinone, 2-Methylthioxanthone, 2-Ethylthioxanthone, 2-Chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-Diethylthioxanthone, benzyldimethylketal, acetphenone dimethylketal, p-dimethylaminobenzoic acid ester, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4 , 6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator (E) in the adhesive composition P is preferably 0.1 part by mass or more as a lower limit value with respect to 100 parts by mass of the active energy ray-curable component (C). In particular, it is preferably 1 part by mass or more. The upper limit is preferably 30 parts by mass or less, and particularly preferably 15 parts by mass or less.

(1-6) Silane coupling agent (F)
The adhesive composition P preferably further contains a silane coupling agent (F). As a result, when the adherend has a glass member, the obtained adhesive has improved adhesion to the glass member. Further, even if the adherend is a plastic plate, the obtained adhesive has improved adhesion to the plastic plate. As a result, the obtained adhesive is more excellent in step followability and blister resistance under high temperature and high humidity conditions.

The silane coupling agent (F) is an organosilicon compound having at least one alkoxysilyl group in the molecule, has good compatibility with the (meth) acrylic acid ester copolymer (A), and has light transmittance. It is preferable to have.

Examples of the silane coupling agent (F) include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacrypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and the like. Silicon compounds having an epoxy structure such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane Contains amino groups such as silicon compound, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane Contains silicon compound, 3-chloropropyltrimethoxysilane, 3-isocyanuspropyltriethoxysilane, or at least one of these and an alkyl group such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. Examples thereof include a condensate with a silicon compound. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent (F) in the adhesive composition P is preferably 0.01 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). In particular, it is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. Further, the content is preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less, and further preferably 0.3 part by mass or less.

(1-7) Various Additives In the tacky composition P, if desired, various additives usually used for acrylic pressure-sensitive adhesives, such as ultraviolet absorbers, antistatic agents, tackifiers, antioxidants, etc. Light stabilizers, softeners, fillers, refractive index adjusters and the like can be added. The polymerization solvent and the dilution solvent described later are not included in the additives constituting the adhesive composition P.

(2) Production of Adhesive Composition The adhesive composition P produced a (meth) acrylic acid ester copolymer (A), and the obtained (meth) acrylic acid ester copolymer (A) and heat The cross-linking agent (B), the active energy ray-curable component (C), and the polyrotaxane compound (D) are mixed, and if desired, a photopolymerization initiator (E), a silane coupling agent (F), and an additive are added. Can be manufactured by adding.

The (meth) acrylic acid ester copolymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by an ordinary radical polymerization method. The polymerization of the (meth) acrylic acid ester copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator, if desired. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane1-carbonitrile), and 2 , 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate) , 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl)) Propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumenehydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples thereof include dicarbonate, t-butylperoxyneodecanoate, t-butylperoxyvivarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

Once the (meth) acrylic acid ester copolymer (A) is obtained, the solution of the (meth) acrylic acid ester copolymer (A) contains the heat-crosslinking agent (B), the active energy ray-curable component (C), and the like. A tacky composition P is obtained by adding the polyrotaxane compound (D), and optionally a photopolymerization initiator (E), a silane coupling agent (F), and an additive and mixing them well.

The adhesive composition P is appropriately diluted with a diluting solvent or the like in addition to the above-mentioned polymerization solvent in order to adjust the viscosity to an appropriate level for coating and to adjust the pressure-sensitive adhesive layer to a desired film thickness. It may be a coating solution described later. Examples of the diluting solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like, and two or more kinds may be used in combination.

(3) Formation of Adhesive Layer When the adhesive composition P is used for forming the adhesive layer 11, the adhesive layer 11 is formed by thermally cross-linking the adhesive composition P. That is, the adhesive composition P is crosslinked by heat treatment. In addition, this heat treatment can also serve as a drying treatment after the application of the adhesive composition P.

The heating temperature of the heat treatment is preferably 50 to 150 ° C., particularly preferably 70 to 120 ° C. The heating time is preferably 10 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. Further, after the heat treatment, it is particularly preferable to provide a curing period of about 1 to 2 weeks at room temperature (for example, 23 ° C., 50% RH).

By the above heat treatment (and curing), the (meth) acrylic acid ester copolymer (A) is satisfactorily crosslinked via the heat crosslinking agent (B).

The thickness of the pressure-sensitive adhesive layer 11 (value measured according to JIS K7130) is preferably 20 μm or more, more preferably 25 μm or more, particularly preferably 30 μm or more, and further preferably 30 μm or more as the lower limit value. It is preferably 50 μm or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is 20 μm or more, the desired adhesive strength is likely to be exhibited. Further, when the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is 30 μm or more, it is possible to secure sufficient step followability with respect to a normal step of the display body constituent member.

The thickness of the pressure-sensitive adhesive layer 11 is preferably 500 μm or less, more preferably 300 μm or less, particularly preferably 150 μm or less, and further preferably 80 μm or less as an upper limit value. When the upper limit of the thickness of the pressure-sensitive adhesive layer 11 is 500 μm or less, workability such as cutability becomes good. Further, when the upper limit value is 150 μm or less, the blister resistance becomes more excellent. The pressure-sensitive adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

(4) Gel fraction (before irradiation with active energy rays)
The gel fraction of the pressure-sensitive adhesive (before irradiation with active energy rays) constituting the pressure-sensitive adhesive layer 11 is preferably 30% or more, more preferably 40% or more, and more preferably 50% or more as the lower limit value. Is particularly preferable, and 52.5% or more is further preferable. When the lower limit of the gel fraction of the pressure-sensitive adhesive before irradiation with active energy rays is equal to or higher than the above, the cohesive force of the pressure-sensitive adhesive layer 11 is improved, and the film strength becomes higher. The gel fraction of the pressure-sensitive adhesive before irradiation with active energy rays is preferably 70% or less, particularly preferably 65% or less, and further preferably 60% or less as an upper limit value. When the upper limit of the gel fraction of the pressure-sensitive adhesive before irradiation with active energy rays is not more than the above, the pressure-sensitive adhesive does not become too hard, and the initial step followability becomes better. The method for measuring the gel fraction of this pressure-sensitive adhesive (before irradiation with active energy rays) is as shown in a test example described later.

2. 2. Release sheet The release sheets 12a and 12b include, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and the like. Polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film , Fluororesin film and the like are used. In addition, these crosslinked films are also used. Further, these laminated films may be used.

It is preferable that the peeling surfaces (particularly the surfaces in contact with the pressure-sensitive adhesive layer 11) of the release sheets 12a and 12b are subjected to a peeling treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Of the release sheets 12a and 12b, it is preferable that one release sheet is a heavy release type release sheet having a large release force and the other release sheet is a light release type release sheet having a small release force.

The thickness of the release sheets 12a and 12b is not particularly limited, but is usually about 20 to 150 μm.

3. 3. Manufacture of Adhesive Sheet The adhesive sheet 1 can be manufactured by a conventional method.
As an example of manufacturing the pressure-sensitive adhesive sheet 1 using the pressure-sensitive adhesive composition P, the coating liquid of the pressure-sensitive adhesive composition P is applied to the peeled surface of one of the peeling sheets 12a (or 12b) and heat-treated. After the adhesive composition P is thermally crosslinked to form a coating layer, the peeling surface of the other release sheet 12b (or 12a) is superposed on the coating layer. If a curing period is required, the curing period is set, and if the curing period is not required, the coating layer becomes the adhesive layer 11 as it is. As a result, the adhesive sheet 1 is obtained. The conditions for heat treatment and curing are as described above.

As another production example of the pressure-sensitive adhesive sheet 1 using the pressure-sensitive adhesive composition P, the coating liquid of the pressure-sensitive adhesive composition P is applied to the peeling surface of one of the release sheets 12a, and heat treatment is performed to obtain the pressure-sensitive adhesive composition. The material P is thermally crosslinked to form a coating layer to obtain a release sheet 12a with the coating layer. Further, the coating liquid of the adhesive composition P is applied to the peeling surface of the other release sheet 12b, heat-treated to heat-crosslink the adhesive composition P to form a coating layer, and the coating layer is attached. To obtain the release sheet 12b of. Then, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are bonded so that both coating layers are in contact with each other. When the curing period is required, the curing period is set, and when the curing period is not required, the laminated coating layer becomes the pressure-sensitive adhesive layer 11. As a result, the adhesive sheet 1 is obtained. According to this production example, stable production is possible even when the pressure-sensitive adhesive layer 11 is thick.

As a method of applying the coating liquid of the adhesive composition P, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used.

[Display body]
The display body according to the present embodiment includes one display body component, another display body component, and a cured pressure-sensitive adhesive layer for bonding one display body component and another display body component to each other. It is equipped with. The cured pressure-sensitive adhesive layer is preferably one obtained by curing a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer 11) made of an active energy ray-curable pressure-sensitive adhesive containing a polyrotaxane compound by irradiation with active energy rays. Specifically, the cured pressure-sensitive adhesive layer has a crosslinked structure composed of a (meth) acrylic acid ester copolymer (A) and a heat-crosslinking agent (B), and has an active energy ray-curable component (C). ), And a pressure-sensitive adhesive containing the polyrotaxane compound (D). In other words, the cured adhesive layer is preferably a pressure-sensitive adhesive layer (adhesive layer 11) made of a pressure-bonded adhesive obtained by thermally cross-linking the above-mentioned adhesive composition P and cured by irradiation with active energy rays. ..

Since the cured adhesive layer has excellent stress relaxation properties and high film strength, it exhibits excellent step followability and blister resistance. Therefore, even when the display body is placed under high temperature and high humidity conditions, for example, 85 ° C. and 85% RH conditions for 72 hours, it is possible to suppress the occurrence of bubbles, floats, peeling, etc. in the vicinity of the step. In addition, the generation of blisters such as air bubbles, floating, and peeling at the interface between the display body component and the cured adhesive layer is suppressed. Further, since stress is unlikely to remain inside the adhesive layer after curing, bending of the display body constituent member due to the stress is suppressed.

The gel fraction of the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is preferably 50% or more, particularly preferably 60% or more, and further preferably 65% or more. The gel content of the adhesive in the adhesive layer after curing is determined by the active energy ray-curing of the adhesive (when the adhesive composition P is used, the active energy ray-curable component (D)). It is higher than the gel content of the adhesive in the adhesive layer before linear curing. When the lower limit of the gel fraction of the adhesive after irradiation with active energy rays is equal to or higher than the above, the adhesive layer after curing of the display body has more excellent step followability and blister resistance under high temperature and high humidity conditions. It becomes.

The gel fraction of the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is preferably 90% or less, particularly preferably 85% or less, and further preferably 80% or less. When the upper limit of the gel content of the adhesive in the cured adhesive layer is not more than the above, it is possible to prevent the adhesive strength of the cured adhesive layer from being lowered and the durability from being deteriorated. The method for measuring the gel fraction of the pressure-sensitive adhesive in the pressure-sensitive adhesive layer after curing is as shown in a test example described later.

The total light transmittance (value measured in accordance with JIS K7361-1: 1997) of the cured adhesive layer is preferably 90% or more, particularly preferably 95% or more, and further 98%. % Or more is preferable. When the total light transmittance is 90% or more, the transparency is high and it is suitable for optical applications (for displays).

The pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer was molded into a thickness of 500 μm, a width of 10 mm, and a length of 75 mm, the measurement range was 20 mm in length, and the speed was 200 mm / min in an environment of 23 ° C. and 50% RH. Stress relaxation rate represented by the following formula based on the maximum stress value measured by performing a tensile test to extend 150% and the stress value 60 seconds after the start of measurement (hereinafter, also referred to as "stress value after 60 seconds"). Is preferably 45% or more, particularly preferably 48% or more, and further preferably 50% or more. The upper limit of the stress relaxation rate is not particularly limited, but is usually preferably 99% or less, particularly preferably 95% or less, and further preferably 65% or less.
Stress relaxation rate (%) = {(maximum stress value-60 seconds later stress value) / maximum stress value} x 100

When the stress relaxation rate is equal to or higher than the above lower limit value, it can be said that the stress relaxation property at the time of application is excellent. As a result, the cured adhesive layer is excellent in step followability and is a display body component member. Can suppress the curvature of. In the present embodiment, by using the above-mentioned pressure-sensitive adhesive, a post-curing pressure-sensitive adhesive layer having the above-mentioned stress relaxation rate can be formed.

Further, the maximum stress value measured by performing the tensile test on the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is preferably 0.01 N or more, particularly preferably 0.012 N or more, and further. It is preferably 0.015N or more. The upper limit of the maximum stress value is not particularly limited, but is usually preferably 3N or less, particularly preferably 1N or less, further preferably 0.5N or less, and 0.1N. Most preferably: In the post-curing pressure-sensitive adhesive layer of the present embodiment, by using the above-mentioned pressure-sensitive adhesive, even if the maximum stress value is large as described above, a large stress relaxation rate is exhibited as described above, and the stress relaxation property is excellent.

On the other hand, for the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer, the stress value after 60 seconds measured by performing the above-mentioned tensile test is preferably 0.5 N or less, and particularly preferably 0.1 N or less. Further, it is preferably 0.05 N or less. The lower limit of the stress value after 60 seconds is not particularly limited, but is usually preferably 0.001N or more, particularly preferably 0.005N or more, and further preferably 0.009N or more. .. In the post-curing pressure-sensitive adhesive layer of the present embodiment, the stress value after 60 seconds can be reduced by using the above-mentioned pressure-sensitive adhesive, and thus a large stress relaxation rate as described above can be obtained.

In the cured adhesive layer, the step follow-up rate (%) represented by the following formula is preferably 20% or more as a lower limit value, particularly preferably 40% or more, and further 50% or more. It is preferable to have. The upper limit of the step follow-up rate is not particularly limited, but is usually preferably 80% or less, and particularly preferably 70% or less.
Step follow-up rate (%) = {(Height of step (μm) maintained in a buried state without air bubbles, floating, peeling, etc. after a predetermined durability test) / (Thickness of adhesive layer)} × 100
The test method for the step follow-up rate is as shown in a test example described later.

When the step-following rate of the cured adhesive layer is within the above range, the cured adhesive layer satisfactorily follows the step of the display body component even under high temperature and high humidity conditions, and bubbles and floats in the vicinity of the step. , Peeling and the like are suppressed, and thus light reflection loss is suppressed.

Examples of the display body include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, and the like, and may be a touch panel. Further, the display body may be a member constituting a part thereof.

The first display body constituent member is preferably a protective panel made of a glass plate, a plastic plate, or the like, or a laminated body containing them. The first display body component may have a step on the surface on the pressure-sensitive adhesive layer side, and in that case, it is preferable to have a step due to the printing layer. This printed layer is generally formed in a frame shape.

The glass plate is not particularly limited, and for example, chemically strengthened glass, non-alkali glass, quartz glass, soda lime glass, barium / strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate. Examples include glass. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

The plastic plate is not particularly limited, and examples thereof include an acrylic plate and a polycarbonate plate. The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

Various functional layers (electrode layer, silica layer, hard coat layer, antiglare layer, etc.) may be provided on one side or both sides of the glass plate or the plastic plate, or optical members are laminated. You may.

The material constituting the print layer is not particularly limited, and a known material for printing is used. The lower limit of the thickness of the printed layer, that is, the height of the step is preferably 3 μm or more, more preferably 10 μm or more, particularly preferably 20 μm or more, and most preferably 30 μm or more. .. When the lower limit value is equal to or higher than the above value, it is possible to sufficiently secure concealment such as making the electrical wiring invisible to the viewer. The upper limit is preferably 100 μm or less, more preferably 80 μm or less, and particularly preferably 50 μm or less. When the upper limit value is not more than the above, it is possible to prevent deterioration of the step followability of the pressure-sensitive adhesive layer with respect to the printing layer.

The second display body component is an optical member to be attached to the first display body component, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic EL)). (Module, etc.), an optical member as a part of the display body module, or a laminated body including the display body module, and the laminated body may have an electrode.

Examples of the optical member include an electrode film, a transparent conductive film, a film sensor, a metal nanowire film, a wire grid polarizing film, and the like.

Examples of the electrodes include metal electrodes made of copper, silver and the like (including mesh-shaped and grid-shaped ones), transparent conductive films made of tin-doped indium oxide (ITO) and the like (including patterned ones), and the like. Be done.

Here, as an example of the display body according to the present embodiment, FIG. 2 shows a capacitance type touch panel 2. The touch panel 2 is laminated on the display module 3, the first film sensor 5a laminated on the display module 3 via the first adhesive layer 4, and the second adhesive layer 4 on the display module 3. A second film sensor 5b and a cover material 6 laminated on the second film sensor 5b via a third adhesive layer 4 are provided. A print layer 7 is formed on the surface of the cover material 6 on the side of the third adhesive layer 4, and therefore, there is a step depending on the presence or absence of the print layer 7.

Any one layer of the first to third pressure-sensitive adhesive layers 4 is a cured pressure-sensitive adhesive layer 11', which is obtained by curing the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1 by irradiation with active energy rays, preferably. , All of the first to third pressure-sensitive adhesive layers 4 are the cured pressure-sensitive adhesive layers 11'. When all of the first to third pressure-sensitive adhesive layers 4 are the cured pressure-sensitive adhesive layer 11', the display module 3, the first film sensor 5a, the second film sensor 5b, and the cover material 6 are the above-mentioned first. Corresponds to the display body component 1 or the second display body component.

When any of the first to third pressure-sensitive adhesive layers 4 is not the cured pressure-sensitive adhesive layer 11', the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 4 is not particularly limited. Examples of the adhesive in this case include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, polyvinyl ether adhesives, etc. Among them, acrylic adhesives are preferable. ..

The first film sensor 5a and the second film sensor 5b in the present embodiment each include a base film 51 and an electrode 52 formed on the base film 51. The base film 51 is not particularly limited, and for example, a polyethylene terephthalate film, an acrylic film, a polycarbonate film, or the like is used.

The electrode 52 is made of, for example, a metal electrode made of copper, silver or the like, a patterned transparent conductive film made of tin-doped indium oxide (ITO) or the like.

The electrode 52 of the first film sensor 5a and the electrode 52 of the second film sensor 5b usually form a circuit pattern in the X-axis direction on one side and a circuit pattern in the Y-axis direction on the other side.

The electrode 52 of the second film sensor 5b in the present embodiment is located above the second film sensor 5b in FIG. On the other hand, the electrode 52 of the first film sensor 5a is located above the first film sensor 5a in FIG. 2, but is not limited to this, and is below the first film sensor 5a. It may be located in.

An example of the manufacturing method of the touch panel 2 will be described below. In this example, it is assumed that all of the first to third pressure-sensitive adhesive layers 4 are the cured pressure-sensitive adhesive layers 11'.
First, as the adhesive sheet 1, a first adhesive sheet 1, a second adhesive sheet 1, and a third adhesive sheet 1 are prepared.

One of the release sheets 12a is peeled off from the second adhesive sheet 1, and the exposed second adhesive layer 11 is attached to the first film sensor 5a so as to be in contact with the electrode 52 of the first film sensor 5a. It fits. Further, one of the release sheets 12a is peeled off from the third adhesive sheet 1, and the exposed third adhesive layer 11 is brought into contact with the electrode 52 of the second film sensor 5b so that the second film sensor 5b is in contact with the electrode 52. And stick it together.

Then, the other release sheet 12b of the second adhesive sheet is peeled off, and the exposed second adhesive layer 11 is the side on which the third adhesive layer 11 of the second film sensor 5b is laminated. Both are bonded so as to be in contact with the opposite surface (exposed surface of the base film 51 of the first film sensor 5b). As a result, a laminate obtained by sequentially laminating the release sheet 12b, the third pressure-sensitive adhesive layer 11, the second film sensor 5b, the second pressure-sensitive adhesive layer 11, and the first film sensor 5a is obtained.

Next, the release sheet 12b is peeled off from the laminate so that the printed layer 7 side of the cover material 6 is in contact with the third adhesive layer 11 with respect to the exposed third adhesive layer 11. Material 6 is pasted together. At this time, since the third pressure-sensitive adhesive layer 11 is excellent in step-following property at the time of sticking, it is possible to prevent gaps and floating from occurring in the vicinity of the step due to the printing layer 7.

Subsequently, one of the release sheets 12a is peeled off from the first adhesive sheet 1, and the exposed first adhesive layer 11 is applied to the surface of the laminate on the first film sensor 5a side (first film sensor 5a). (Exposure surface of the base film 51). Then, the other release sheet 12b is peeled from the first pressure-sensitive adhesive layer 11, and the laminated body is attached to the display body module 3 so that the exposed first pressure-sensitive adhesive layer 11 is in contact with the display body module 3. ..

By the above bonding, the cover material 6, the third adhesive layer 11, the second film sensor 5b, the second adhesive layer 11, the first film sensor 5a, the first adhesive layer 11 and the display module. A structure in which 3 is sequentially laminated is obtained.

Next, the first to third pressure-sensitive adhesive layers are irradiated with active energy rays from any side of the above-mentioned structure, preferably from the cover material 6 side, and the pressure-sensitive adhesive layers are cured, respectively. After curing, the pressure-sensitive adhesive layer is 11'. As a result, the touch panel 2 shown in FIG. 2 is manufactured.

Here, the active energy beam refers to an electromagnetic wave or a charged particle beam having an energy quantum, and specific examples thereof include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays, which are easy to handle, are particularly preferable.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW / cm ² . Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 200~2000mJ / cm ^2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 grad.

Since each cured adhesive layer 11'in the obtained touch panel 2 has excellent stress relaxation properties and high film strength, the touch panel 2 is subjected to high temperature and high humidity conditions, for example, 85 ° C. and 85% RH conditions. Even after being left for 72 hours, the occurrence of air bubbles, floating, peeling, etc. in the vicinity of the step due to the printing layer 7 is suppressed. Further, even when outgas is generated from a display body component made of a plastic plate or the like, particularly the cover material 6, blisters such as air bubbles, floats, and peeling at the interface between the cured adhesive layer 11'and the display body component can be used. Occurrence is also suppressed. Further, since stress is unlikely to remain inside the adhesive layer 11'after curing, bending of the display body constituent members, particularly the first film sensor 5a and the second film sensor 5b, due to the stress is suppressed. To. As a result, the touch panel 2 is less likely to cause problems such as display unevenness.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, either one of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted. Further, some display body constituent members in the touch panel 2 may be omitted, or other display body constituent members may be further laminated.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. 1. Preparation of (meth) acrylic acid ester copolymer 65 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of isobornyl acrylate, 5 parts by mass of N-acryloyl morpholine, and 15 parts by mass of 2-hydroxyethyl acrylate are copolymerized. , (Meta) acrylic acid ester copolymer (A) was prepared. When the molecular weight of this (meth) acrylic acid ester copolymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 500,000.

2. 2. Preparation of Adhesive Composition 100 parts by mass (solid content conversion value; the same applies hereinafter) of the (meth) acrylic acid ester copolymer (A) obtained in the above step 1 and trimethylol propane as a thermal cross-linking agent (B). 0.25 parts by mass of modified tolylene diisocyanate, 5.13 parts by mass of ε-caprolactone-modified tris- (2-acryloxyethyl) isocyanurate as an active energy ray-curable component (C), and a polyrotaxane compound (D) ( Made by Advanced Soft Materials, product name "SELM Superpolymer SH3400P", linear molecule: polyethylene glycol, cyclic molecule: α-cyclodextrin having hydroxypropyl group and caprolactone chain, block group: adamantan group, weight average molecular weight (Mw) 700,000, hydroxyl value 72 mgKOH / g) 7.5 parts by mass, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide 0.57 parts by mass as the photopolymerization initiator (E), and silane A coating solution of the adhesive composition was obtained by mixing 0.28 parts by mass of 3-glycidoxypropyltrimethoxysilane as the coupling agent (F), stirring well, and diluting with methyl ethyl ketone. ..

3. 3. Production of Adhesive Sheet Peeling of a heavy-release type release sheet (manufactured by Lintec Corporation, product name "SP-PET752150") in which one side of a polyethylene terephthalate film is peeled off with a silicone-based release agent from the obtained coating solution of the adhesive composition. The treated surface was coated with a knife coater. Then, the coating layer was heat-treated at 90 ° C. for 1 minute to form a coating layer.

Next, the coating layer on the heavy release type release sheet obtained above and the light release type release sheet obtained by peeling one side of the polyethylene terephthalate film with a silicone-based release agent (manufactured by Lintec, product name "SP-PET382120"). The adhesive layer having a thickness of 175 μm was formed by laminating and curing the light peeling type peeling sheet so that the peeled surface of the light peeling type peeling sheet was in contact with the coating layer and curing under the conditions of 23 ° C. and 50% RH for 7 days. An adhesive sheet having the structure, that is, a heavy release type release sheet / an adhesive layer (thickness: 175 μm) / a light release type release sheet, was produced. The thickness of the adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by Teclock Co., Ltd., product name "PG-02") in accordance with JIS K7130.

Here, Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester copolymer (A) is 100 parts by mass (solid content conversion value).

[Examples 2 to 5 and Comparative Examples 1 to 3]
The blending amounts of the thermal cross-linking agent (B), the active energy ray-curable component (C), the polyrotaxane compound (D) and the photopolymerization initiator (E), and the thickness of the pressure-sensitive adhesive layer are changed as shown in Table 1. Except for the above, an adhesive sheet was produced in the same manner as in Example 1.

Here, the above-mentioned weight average molecular weight (Mw) is a standard polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard volume HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
TSK gel G2000HXL
・ Measurement solvent: tetrahydrofuran ・ Measurement temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)
The adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 80 mm × 80 mm, the adhesive layer was wrapped in a polyester mesh (mesh size 200), the mass was weighed with a precision balance, and the above mesh was used. The mass of the pressure-sensitive adhesive alone was calculated by subtracting the mass of a single substance. The mass at this time is M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C.) for 72 hours. Then, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) × 100. As a result, the gel fraction of the pressure-sensitive adhesive (before UV irradiation) was derived. The results are shown in Table 2.

On the other hand, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples was irradiated with ultraviolet rays under the following conditions through the light-release type release sheet to cure the pressure-sensitive adhesive layer and then the pressure-sensitive adhesive layer. And said. With respect to the adhesive of the adhesive layer after curing, the gel fraction (after irradiation with ultraviolet rays) was derived in the same manner as described above. The results are shown in Table 2.

<Ultraviolet irradiation conditions>
・ Uses high-pressure mercury lamp ・ Illuminance 200mW / cm ² , light intensity 2000mJ / cm ²
・ UV illuminance / photometer uses "UVPF-A1" manufactured by iGraphics.

[Test Example 2] (Measurement of total light transmittance)
The light release type release sheet was peeled from the adhesive sheets obtained in Examples and Comparative Examples, and the exposed adhesive layer was attached to the glass. Next, under the same conditions as in Test Example 1, ultraviolet rays were irradiated through the heavy-release type release sheet to cure the pressure-sensitive adhesive layer to form a cured pressure-sensitive adhesive layer, which was used as a measurement sample. After performing background measurement with glass, all light rays of the above measurement sample were measured using a haze meter (manufactured by Nippon Denshoku Kogyo Co., Ltd., product name "NDH-2000") according to JIS K7361-1: 1997. The transmittance (%) was measured. The results are shown in Table 2.

[Test Example 3] (Tensile test)
A plurality of the pressure-sensitive adhesive layers were laminated so that the total thickness of the pressure-sensitive adhesive layers in the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples was 500 μm, and only the release sheet of the outermost layer of the laminated body remained. The pressure-sensitive adhesive layer of the obtained laminate was irradiated with ultraviolet rays through the release sheet under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer.

Next, a sample having a width of 10 mm and a length of 75 mm was cut out from the laminate, and the release sheet laminated on the outermost layer of the laminate was peeled off. Then, set the sample so that the sample measurement site has a width of 10 mm and a length of 20 mm (extension direction), and use a tensile tester (manufactured by Orientec, product name "Tencilon") in an environment of 23 ° C. and 50% RH. It was stretched by 150% at a tensile speed of 200 mm / min, and the maximum stress value (N) and the stress value 60 seconds after the start of measurement (stress value after 60 seconds; N) were measured. Then, the stress relaxation rate (%) represented by the following formula was calculated from these values. The results of each are shown in Table 2.
Stress relaxation rate (%) = {(maximum stress value-60 seconds later stress value) / maximum stress value} x 100

[Test Example 4] (Measurement of step follow-up rate)
On the surface of a glass plate (manufactured by NSG Precision Co., Ltd., product name "Corning Glass Eagle XG", length 90 mm x width 50 mm x thickness 0.5 mm), UV curable ink (manufactured by Teikoku Inks, product name "POS-911 ink") ) Was screen-printed in a frame shape (outer shape: length 90 mm × width 50 mm, width 5 mm) so that the coating thickness was any one of 25 μm, 30 μm, and 90 μm. Next, the printed ultraviolet curable ink is cured by irradiating with ultraviolet rays (80 W / cm ² , ² metal halide lamps, lamp height 15 cm, belt speed 10 to 15 m / min), and a step (height of the step) due to printing is cured. S: A stepped glass plate having one of 25 μm, 30 μm, and 90 μm) was produced.

The lightly peelable release sheet was peeled off from the adhesive sheets obtained in Examples and Comparative Examples, and the exposed adhesive layer was a polyethylene terephthalate film having an easy adhesive layer (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: It was bonded to an easy-adhesion layer of 100 μm). Next, the heavy-release type release sheet is peeled off to expose the pressure-sensitive adhesive layer, and a laminator (manufactured by Fujipla, product name "LPD3214") is used to provide a step so that the pressure-sensitive adhesive layer covers the entire surface of the frame-shaped print. Laminated on a glass plate. Then, it was autoclaved for 30 minutes under the conditions of 50 ° C. and 0.5 MPa, and left at normal pressure at 23 ° C. and 50% RH for 24 hours.

The pressure-sensitive adhesive layer of the obtained laminate was irradiated with ultraviolet rays through the polyethylene terephthalate film under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. Then, it was stored for 72 hours under high temperature and high humidity conditions of 85 ° C. and 85% RH (durability test), and then the step followability was evaluated. The step followability is judged by whether or not the printed step is completely filled by the cured adhesive layer, and if bubbles, floats, peeling, etc. are observed at the interface between the printed step and the cured adhesive layer, , It is judged that the printing step could not be followed. Here, the step followability was evaluated as the step follow rate (%) represented by the following formula. The results are shown in Table 2.
Step follow-up rate (%) = {(Height of step (μm) maintained in a buried state without bubbles, floating, peeling, etc. after durability test) / (Thickness of adhesive layer after curing)} × 100

[Test Example 5] (Evaluation of blister resistance)
A polyethylene terephthalate film (manufactured by Oike Kogyo Co., Ltd., ITO film, thickness:) in which a transparent conductive film made of tin-doped indium oxide (ITO) is provided on one side of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples. On the polycarbonate layer side of a resin plate (manufactured by Mitsubishi Gas Chemicals, product name "Iupilon Sheet MR-58U", thickness: 0.8 mm) having a transparent conductive film of 125 μm), a polymethyl methacrylate layer and a polycarbonate layer. I sandwiched it with a face. Then, it was autoclaved for 30 minutes under the conditions of 50 ° C. and 0.5 MPa, and left at normal pressure at 23 ° C. and 50% RH for 24 hours.

The pressure-sensitive adhesive layer of the obtained laminate was irradiated with ultraviolet rays through the resin plate under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. Then, it was stored for 72 hours under high temperature and high humidity conditions of 85 ° C. and 85% RH. Then, after curing, the state at the interface between the pressure-sensitive adhesive layer and the adherend was visually confirmed, and the blister resistance was evaluated according to the following criteria. The results are shown in Table 2.
◎… No bubbles, bubble traces and floating / peeling ○… 1-2 bubbles with a diameter of less than 1 mm △… 3 or more bubbles with a diameter of less than 1 mm ×… Bubbles with a diameter of 1 mm or more or floating / peeling Occurrence

[Test Example 6] (Evaluation of cut suitability)
A plurality of layers of the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were laminated to obtain a laminated body having a total thickness of 1 mm. The outermost surfaces on both sides of the laminated body were in a state where a release film was attached. The laminate was cut together with the release film by a cutting device (manufactured by Ogino Seisakusho Co., Ltd., product name "Super Cutter PN1-600"). In this way, 10 samples were obtained, and the cut surface (length: 100 mm) of the pressure-sensitive adhesive layer after cutting was visually confirmed for the 10 samples, and the cut suitability was evaluated according to the following criteria. The results are shown in Table 2.
⊚: No chipping of adhesive layer on all cutting surfaces of 10 samples out of 10 samples ○: No chipping of adhesive layer on cutting surfaces of 7 to 9 samples out of 10 samples Δ: No chipping of adhesive layer on cutting surfaces of 3 to 6 samples out of 10 samples No chipping of adhesive layer ×: No chipping of adhesive layer on the cut surface of 2 samples or less out of 10 samples

As can be seen from Table 2, the cured pressure-sensitive adhesive layer obtained in the examples was excellent in both step-following property and blister resistance. Further, it was found that the pressure-sensitive adhesive layer (before UV curing) obtained in Examples had excellent cut suitability and high film strength.

The adhesive sheet of the present invention is suitable for bonding a protective panel having a step and a desired display body component, or a film sensor that is easily curved by stress and a desired display body component. Can be used.

1 ... Adhesive sheet 11 ... Adhesive layer 12a, 12b ... Release sheet 2 ... Touch panel 3 ... Display module 4 ... Adhesive layer 11'... After curing Adhesive layer 5a ... First film sensor 5b ... Second film sensor 51 ... Base film 52 ... Electrode 6 ... Cover material 7 ... Printing layer

Claims (11)

An adhesive sheet provided with an adhesive layer for adhering one display body component and another display body component.
The pressure-sensitive adhesive layer
It has a crosslinked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B), and has a crosslinked structure.
With the active energy ray-curable component (C),
An adhesive sheet comprising an active energy ray-curable pressure-sensitive adhesive containing an active energy ray-non-curable polyrotaxane compound (D) . The pressure-sensitive adhesive sheet according to claim 1, wherein the gel content of the pressure-sensitive adhesive is 30% or more and 70% or less. The adhesive sheet according to claim 1 or 2 , wherein the display body constituent member has at least a step on the surface on the side to be bonded. The adhesive sheet includes two release sheets.
The adhesive sheet according to any one of claims 1 to 3 , wherein the pressure-sensitive adhesive layer is sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. A method for manufacturing an adhesive sheet provided with an adhesive layer for adhering one display body constituent member and another display body constituent member.
(Meta) acrylic acid ester copolymer (A) and
Thermal cross-linking agent (B) and
With the active energy ray-curable component (C),
An adhesive sheet characterized by forming an active energy ray-curable pressure-sensitive adhesive layer by applying an adhesive composition containing an active energy ray-non-curable polyrotaxane compound (D) and thermally cross-linking the coating. Manufacturing method. One display body component and
With other display body components,
A display body including a cured adhesive layer for bonding the one display body component and the other display body component to each other.
The cured adhesive layer
It has a crosslinked structure composed of a (meth) acrylic acid ester copolymer (A) and a thermal crosslinking agent (B), and has a crosslinked structure.
A cured product of the active energy ray-curable component (C) and
A display body comprising a pressure-sensitive adhesive containing an active energy ray non-curable polyrotaxane compound (D). The display according to claim 6 , wherein the gel content of the pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer is 50% or more and 90% or less. The display according to claim 6 or 7 , wherein the total light transmittance of the cured pressure-sensitive adhesive layer is 90% or more. The pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer was molded into a thickness of 500 μm, a width of 10 mm, and a length of 75 mm, the measurement range was 20 mm in length, and the speed was 200 mm / min in an environment of 23 ° C. and 50% RH. Based on the maximum stress value measured by performing a tensile test to extend 150% and the stress value 60 seconds after the start of measurement, the stress relaxation rate represented by the following formula is 45% or more and 99% or less. The display body according to any one of claims 6 to 8 .
Stress relaxation rate (%) = {(maximum stress value-stress value 60 seconds after the start of measurement) / maximum stress value} x 100 The pressure-sensitive adhesive in the cured pressure-sensitive adhesive layer was molded into a thickness of 500 μm, a width of 10 mm, and a length of 75 mm, the measurement range was 20 mm in length, and the speed was 200 mm / min in an environment of 23 ° C. and 50% RH. The display according to any one of claims 6 to 9 , wherein the maximum stress value measured by performing a tensile test for stretching by 150% is 0.01 N or more and 3 N or less. A laminated body formed by laminating one display body constituent member and another display body constituent member via the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to any one of claims 1 to 4 is produced.
A method for producing a display body, which comprises irradiating the pressure-sensitive adhesive layer of the laminated body with active energy rays and curing the pressure-sensitive adhesive layer to form a pressure-sensitive adhesive layer after curing.

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