JP2023052174A - Display body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet and a display body capable of suppressing irregularities of transmittance in an adhesive layer.

SOLUTION: In a display body 2A having one display body component 21, another display body component 22, and an adhesive layer 11 for mutually laminating the one display body component 21 and the other display body component 22, at least one of the one display body component 21 and the other display body component 22 has irregularities on a surface in a side laminated by the adhesive layer 11, the adhesive layer 11 has at least a layer of colored adhesive layer 111, a ratio of luminous flux transmittance near the irregularities relative to luminous flux transmittance in a flat part is equal to or more than 0.980, and an adhesive for composing the colored adhesive layer 111 contains a coloring agent of 0.0073 mass% or more.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a pressure-sensitive adhesive sheet to be attached to an adherend having an uneven surface, and a display body using the pressure-sensitive adhesive sheet.

Recent displays (displays), for example, in-vehicle displays in automobile instrument panels, car navigation systems, various instruments provided in consoles, displays such as tablet terminals for general users, commercial tablets 2. Description of the Related Art Image display devices such as liquid crystal display devices and organic electroluminescence devices are increasingly used in terminals, displays such as digital signage, and displays such as outdoor digital signage.

As described above, in display bodies including those for in-vehicle use, when the display body is turned off, it is required to provide a sense of unity with the peripheral members of the display body, for example, the frame material, and to improve the design. Sometimes. For that purpose, it is conceivable to color the display. As an example, Patent Literature 1 discloses an invention in which a colored layer containing a coloring pigment dispersed in an adhesive is provided as part of a layer constituting a display.

JP 2012-234028 A

In the invention described in Patent Document 1, the colored layer is provided so as to be in contact with the masking layer formed in the shape of a frame in a plan view of the display body, that is, the step. However, in the display body having such a structure, there is a problem that the colored layer has uneven transmittance, which causes uneven luminance in the display body.

The present invention has been made in view of the actual situation as described above, and an object of the present invention is to provide a pressure-sensitive adhesive sheet and a display body capable of suppressing uneven transmittance in the pressure-sensitive adhesive layer.

In order to achieve the above objects, firstly, the present invention provides a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer to be applied to an adherend having an uneven surface, wherein the pressure-sensitive adhesive layer comprises at least one colored adhesive layer. It is a laminate of an adhesive layer and at least one colorless adhesive layer, wherein the colorless adhesive layer is positioned on the surface of the adhesive layer that contacts the unevenness of the adherend. A pressure-sensitive adhesive sheet is provided (Invention 1).

In the above invention (Invention 1), when the pressure-sensitive adhesive layer is brought into contact with and follows the irregularities of the adherend, the layer that contacts the irregularities of the adherend is not a colored pressure-sensitive adhesive layer but a colorless pressure-sensitive adhesive layer. . The unevenness of the adherend can be absorbed to some extent by the colorless pressure-sensitive adhesive layer. Therefore, it is possible to suppress the compression or deformation of the colored pressure-sensitive adhesive layer due to the irregularities of the adherend, thereby suppressing the uneven transmittance of the pressure-sensitive adhesive layer.

In the above invention (Invention 1), it is preferable that the thickness of the colorless pressure-sensitive adhesive layer located on the surface of the adherend in contact with the irregularities is larger than the depth or height of the irregularities of the adherend ( Invention 2).

In the above inventions (inventions 1 and 2), the pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer for bonding one display body-constituting member and another display body-constituting member (invention 3). .

In the above inventions (inventions 1 to 3), the storage elastic modulus at 23° C. of the pressure-sensitive adhesive constituting the colorless pressure-sensitive adhesive layer is preferably 0.01 MPa or more and 1 MPa or less (invention 4).

In the above inventions (Inventions 1 to 4), the storage elastic modulus at 23° C. of the pressure-sensitive adhesive constituting the colored pressure-sensitive adhesive layer is preferably 0.01 MPa or more and 1 MPa or less (Invention 5).

In the above inventions (inventions 1 to 5), it is preferable to include two release sheets and the adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets (invention 6).

Secondly, the present invention comprises one display body constituent member, another display body constituent member, and an adhesive layer for adhering the one display body constituent member and the other display body constituent member together. In the display body, at least one of the one display body-constituting member and the other display body-constituting member has unevenness on a side to be bonded by the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (Inventions 1 to 6) (Invention 7).

Thirdly, the present invention comprises one display body constituting member, another display body constituting member, and an adhesive layer for adhering the one display body constituting member and the other display body constituting member together. In the display body, at least one of the one display body-constituting member and the other display body-constituting member has unevenness on a side to be bonded by the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is provided with at least one colored adhesive layer, and the ratio of the light flux transmittance in the vicinity of the unevenness to the light flux transmittance in the flat part is 0.980 or more. Provide (Invention 8).

In the above inventions (inventions 7 and 8), the unevenness may be unevenness due to a printed layer provided on a part of the display in plan view (invention 9).

In the above inventions (inventions 7 and 8), the unevenness may be unevenness due to a plurality of light emitters provided on the substrate (invention 10).

According to the pressure-sensitive adhesive sheet and display body according to the present invention, it is possible to suppress uneven transmittance in the pressure-sensitive adhesive layer.

1 is a cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention; FIG. 1 is a cross-sectional view of a display body according to an embodiment of the invention; FIG. FIG. 5 is a cross-sectional view of a display body according to another embodiment of the present invention; FIG. 4 is a cross-sectional view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention; FIG. 2 is a plan view of an adherend used in Test Example (measurement of luminous flux transmittance). FIG. 4 is a cross-sectional view showing a sample produced in a test example (measurement of luminous flux transmittance).

Embodiments of the present invention will be described below.
[Adhesive sheet]
A pressure-sensitive adhesive sheet according to one embodiment of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer to be attached to an adherend having an uneven surface. The pressure-sensitive adhesive layer is a laminate of at least one colored pressure-sensitive adhesive layer and at least one colorless pressure-sensitive adhesive layer. agent layer is located.

Here, when the colored pressure-sensitive adhesive layer is brought into contact with and follows the unevenness of the adherend as in the past, the colored pressure-sensitive adhesive layer is compressed or deformed due to the unevenness of the adherend. do. As a result, the color of the colored pressure-sensitive adhesive layer becomes uneven and the transmittance becomes uneven. For example, the portion where the colored pressure-sensitive adhesive layer is compressed has a darker color and a lower transmittance. In contrast, the pressure-sensitive adhesive sheet according to the present embodiment has the above structure, so that the layer that contacts the unevenness of the adherend is not a colored pressure-sensitive adhesive layer but a colorless pressure-sensitive adhesive layer. Therefore, the colored pressure-sensitive adhesive layer is suppressed from being compressed or deformed due to the unevenness of the adherend. Thereby, the unevenness of the transmittance in the pressure-sensitive adhesive layer can be suppressed.

In the pressure-sensitive adhesive sheet according to this embodiment, the thickness of the colorless pressure-sensitive adhesive layer located on the surface in contact with the irregularities on the adherend is preferably greater than the depth or height of the irregularities on the adherend. As a result, the unevenness of the adherend can be absorbed by the colorless pressure-sensitive adhesive layer, and the compression or deformation of the colored pressure-sensitive adhesive layer due to the unevenness can be suppressed more effectively. Therefore, uneven transmittance in the pressure-sensitive adhesive layer is more effectively suppressed.

The pressure-sensitive adhesive layer is preferably a pressure-sensitive adhesive layer for bonding one display body-constituting member and another display body-constituting member. The display body and display body constituent members will be described later. In the display obtained by using the adhesive layer of the adhesive sheet according to the present embodiment, unevenness in transmittance in the adhesive layer is suppressed, thereby suppressing uneven brightness in the display. However, the pressure-sensitive adhesive sheet according to the present embodiment is not limited to use as a display.

FIG. 1 shows a specific configuration as an example of the pressure-sensitive adhesive sheet according to this embodiment.
As shown in FIG. 1, the adhesive sheet 1 is sandwiched between two release sheets 12a and 12b and the two release sheets 12a and 12b so as to be in contact with the release surfaces of the two release sheets 12a and 12b. and an adhesive layer 11 . In this specification, the release surface of the release sheet refers to the surface of the release sheet that has releasability, and includes both the surface that has been subjected to a release treatment and the surface that exhibits releasability without being subjected to a release treatment. .

The adhesive layer 11 in this embodiment is a laminate of one colored adhesive layer 111 and one colorless adhesive layer 112 . However, the present invention is not limited to this, and the colored pressure-sensitive adhesive layer 111 and the colorless pressure-sensitive adhesive layer 112 may each have a plurality of layers. The colorless pressure-sensitive adhesive layer 112 is located on the surface of the pressure-sensitive adhesive layer 11 that contacts the irregularities of the adherend.

1. Each member 1-1. Adhesive Layer The colored adhesive layer 111 is preferably made of an adhesive containing a colorant. On the other hand, the colorless adhesive layer 112 is preferably composed of an adhesive that does not contain a colorant, and is preferably colorless and transparent. Note that "does not contain a coloring agent" means "substantially does not contain a coloring agent". case is also included. The amount is preferably 0.1% by mass or less, particularly preferably 0.01% by mass or less, further preferably 0.001% by mass or less, and preferably 0% by mass. Most preferred.

The type of adhesive that constitutes the colored adhesive layer 111 and the colorless adhesive layer 112 of the adhesive sheet 1 according to the present embodiment is not particularly limited, and examples thereof include an acrylic adhesive, a polyester adhesive, and a polyurethane adhesive. , a rubber-based adhesive, a silicone-based adhesive, or the like. The adhesive may be emulsion type, solvent type or non-solvent type, and may be crosslinked or non-crosslinked. Among them, acrylic pressure-sensitive adhesives are preferable because they have excellent adhesive physical properties, optical properties, and the like.

In addition, the acrylic pressure-sensitive adhesive may be active energy ray-curable or non-active energy ray-curable. As the acrylic pressure-sensitive adhesive, a cross-linking type is preferable, and a thermal cross-linking type is more preferable.

The pressure-sensitive adhesive forming the colored pressure-sensitive adhesive layer 111 and the pressure-sensitive adhesive forming the colorless pressure-sensitive adhesive layer 112 may be of the same type or of different types. For example, one may be an active energy ray-curable acrylic pressure-sensitive adhesive and the other may be an active energy ray non-curable acrylic pressure-sensitive adhesive. In addition, even if both are common in active energy ray-curable acrylic adhesive or active energy ray non-curable acrylic adhesive, the composition of the adhesive and the monomer composition of the main polymer are different. may be

The adhesive constituting the colored adhesive layer 111 and the adhesive constituting the colorless adhesive layer 112 specifically contain a (meth)acrylic ester polymer (A) and a cross-linking agent (B). It is preferably obtained by cross-linking an adhesive composition (hereinafter sometimes referred to as "adhesive composition P"). In the case of the colored adhesive layer 111, the adhesive composition P preferably further contains a coloring agent (C). Moreover, when using the said adhesive as an active-energy-ray-curable adhesive, it is preferable that the adhesive composition P contains an active-energy-ray-curable component (D) further.

A pressure-sensitive adhesive obtained from such pressure-sensitive adhesive composition P can exhibit excellent optical properties, adhesive strength, durability (conformability to irregularities under high-temperature and high-humidity conditions, resistance to blistering), and the like. In this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, the concept of "copolymer" is also included in "polymer".

(1) Components of adhesive composition (1-1) (meth)acrylic acid ester polymer (A)
The (meth)acrylic acid ester polymer (A) in the present embodiment contains a reactive group-containing monomer having a reactive group that reacts with the cross-linking agent (B) in the molecule as a monomer unit constituting the polymer. is preferred. A reactive group derived from this reactive group-containing monomer reacts with the cross-linking agent (B) to form a cross-linked structure (three-dimensional network structure), thereby obtaining a pressure-sensitive adhesive having desired cohesion.

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), a monomer having an amino group in the molecule (amino group-containing monomer ) and the like are preferably mentioned. Among these, a hydroxyl group-containing monomer or a carboxy group-containing monomer, which is excellent in reactivity with the cross-linking agent (B), is preferable, and it is also preferable to use a hydroxyl group-containing monomer and a carboxy group-containing monomer together.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, (meth) ) hydroxyalkyl (meth)acrylates such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth)acrylate; Among them, from the viewpoint of the reactivity of the hydroxyl group in the obtained (meth)acrylic acid ester polymer (A) with the crosslinking agent (B) and the copolymerizability with other monomers, hydroxy having 1 to 4 carbon atoms A (meth)acrylic acid hydroxyalkyl ester having an alkyl group is preferred. Specifically, for example, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate and the like are preferred, and 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate are particularly preferred. be done. These may be used alone or in combination of two or more.

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

Examples of amino group-containing monomers include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used alone or in combination of two or more. Nitrogen atom-containing monomers, which will be described later, are excluded from the amino group-containing monomers.

The (meth)acrylic acid ester polymer (A) preferably contains a reactive group-containing monomer as a lower limit of 5% by mass or more, particularly 10% by mass or more, as a monomer unit constituting the polymer. is preferable, and more preferably 15% by mass or more. In addition, the (meth)acrylic acid ester polymer (A) preferably contains a reactive group-containing monomer as the upper limit of 35% by mass or less, particularly 30% by mass or less, as a monomer unit constituting the polymer. It is preferably contained, more preferably 25% by mass or less. When the (meth)acrylic acid ester polymer (A) contains the 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 desired cohesive strength is obtained. Moreover, when the coloring agent (C) is contained, the dispersibility of the coloring agent (C) in the obtained pressure-sensitive adhesive tends to be improved. As a result, the pressure-sensitive adhesive obtained can exhibit suitable cohesive strength, have good reproducibility and uniformity of optical properties, and can easily control the luminous flux transmittance described below to a desired value. Furthermore, when the reactive group-containing monomer is a hydroxyl group-containing monomer, the content is preferably 10% by mass or more, particularly preferably 15% by mass or more. In this case, a predetermined amount of hydroxyl groups remain in the adhesive. Hydroxyl groups are hydrophilic groups, and if such hydrophilic groups are present in a predetermined amount in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, they will penetrate into the adhesive under such high temperature and high humidity conditions. As a result, whitening of the pressure-sensitive adhesive when returned to normal temperature and normal humidity is suppressed (excellent resistance to moist heat whitening).

It is also preferable that the (meth)acrylic acid ester polymer (A) does not contain a carboxy group-containing monomer as a monomer unit constituting the polymer. Since the carboxyl group is an acid component, the absence of the carboxyl group-containing monomer prevents the adhesive from being applied to objects to which the acid is attached, such as transparent conductive films such as tin-doped indium oxide (ITO), metal films, and the like. Even if it exists, it is possible to suppress those problems (corrosion, resistance value change, etc.) caused by the acid. However, it is permissible to contain a predetermined amount of the carboxy group-containing monomer to the extent that such problems do not occur. Specifically, the (meth)acrylic acid ester polymer (A) contains, as a monomer unit, a carboxy group-containing monomer of 0.1% by mass or less, preferably 0.01% by mass or less, more preferably 0.001% by mass. It is allowed to be contained in an amount of mass % or less.

The (meth)acrylic acid ester polymer (A) preferably contains a (meth)acrylic acid alkyl ester as a monomer unit constituting the polymer. Thereby, favorable adhesiveness can be expressed. Alkyl groups may be straight or branched.

As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferable from the viewpoint of adhesiveness. Examples of (meth)acrylic acid alkyl esters having an alkyl group of 1 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-(meth)acrylate, Butyl, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, (meth)acrylic acid Examples include n-dodecyl, myristyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate. Among them, from the viewpoint of further improving the adhesiveness, (meth)acrylic acid esters having an alkyl group having 1 to 8 carbon atoms are preferable, and methyl (meth)acrylate, n-butyl (meth)acrylate or (meth)acryl 2-Ethylhexyl acid is particularly preferred, more preferably methyl methacrylate, n-butyl acrylate or 2-ethylhexyl acrylate. In addition, these may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (A) preferably contains 45% by mass or more, particularly 55% by mass or more, of (meth)acrylic acid alkyl ester as monomer units constituting the polymer. It is preferably contained in an amount of 65% by mass or more. When the lower limit of the content of the (meth)acrylic acid alkyl ester is the above, the (meth)acrylic acid ester polymer (A) can exhibit suitable adhesiveness. Further, when the colorant (C) is contained, there is a tendency that the dispersibility of the colorant (C) in the adhesive agent can be improved, and the (meth)acrylic acid ester polymer (A) has the desired adhesiveness. Damage is suppressed. As a result, the pressure-sensitive adhesive to be obtained can exhibit suitable adhesiveness, have good reproducibility and uniformity of optical properties, and can easily control the luminous flux transmittance, which will be described later, to a desired value. On the other hand, the (meth)acrylic acid ester polymer (A) preferably contains 99% by mass or less, and preferably 95% by mass or less, of (meth)acrylic acid alkyl ester as the monomer units constituting the polymer. is more preferable, particularly preferably 90% by mass or less, and more preferably 85% by mass or less. When the upper limit of the content of the (meth)acrylic acid alkyl ester is the above, a suitable amount of another monomer component such as a reactive functional group-containing monomer is introduced into the (meth)acrylic acid ester polymer (A). be able to.

The (meth)acrylic acid ester polymer (A) preferably contains a monomer having an alicyclic structure in its molecule (alicyclic structure-containing monomer) as a monomer unit constituting the polymer. Since the alicyclic structure-containing monomer is bulky, it is presumed that the presence of this in the polymer widens the distance between the polymers, and the obtained pressure-sensitive adhesive can be made excellent in flexibility. . As a result, the pressure-sensitive adhesive becomes excellent in conformability to irregularities.

The carbon ring of the alicyclic structure in the alicyclic structure-containing monomer may have a saturated structure or may partially have an unsaturated bond. The alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as bicyclic or tricyclic. From the viewpoint of making the distance between the resulting (meth)acrylic acid ester polymer (A) appropriate and imparting higher stress relaxation properties to the pressure-sensitive adhesive, the alicyclic structure is a polycyclic alicyclic structure ( polycyclic structure). Furthermore, in consideration of compatibility between the (meth)acrylic acid ester polymer (A) and other components, the polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, from the viewpoint of imparting stress relaxation properties as described above, the number of carbon atoms in the alicyclic structure (the number of all carbon atoms in the portion forming the ring, and when a plurality of rings are independently present , which means the total number of carbon atoms) is usually preferably 5 or more, particularly preferably 7 or more. On the other hand, although the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, it is preferably 15 or less, particularly preferably 10 or less, from the viewpoint of compatibility as described above.

Specific examples of the alicyclic structure-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, (meth)acrylic Examples include dicyclopentenyl acid, dicyclopentenyloxyethyl (meth)acrylate, and among them, dicyclopentenyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 10), adamantyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 10) or isobornyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 7) is preferred, and isobornyl (meth)acrylate is particularly preferred. and isobornyl acrylate are 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 polymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, it preferably contains 1% by mass or more of the alicyclic structure-containing monomer. In particular, it is preferably contained in an amount of 4% by mass or more, more preferably 8% by mass or more. In addition, the (meth)acrylic acid ester polymer (A) preferably contains 30% by mass or less, particularly 20% by mass or less, of an alicyclic structure-containing monomer as a monomer unit constituting the polymer. is preferable, and it is more preferable to contain 10% by mass or less. When the content of the alicyclic structure-containing monomer is within the above range, the resulting pressure-sensitive adhesive has more excellent conformability to irregularities.

The (meth)acrylic acid ester polymer (A) also preferably contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. Predetermined polarity is imparted to the pressure-sensitive adhesive by allowing nitrogen atom-containing monomers to be present in the polymer as structural units, and excellent affinity is obtained even for adherends having a certain degree of polarity, such as glass. can be As the nitrogen atom-containing monomer, a monomer having a nitrogen-containing heterocyclic ring is preferable from the viewpoint of imparting appropriate rigidity to the (meth)acrylic acid ester polymer (A). In addition, from the viewpoint of increasing the degree of freedom of the portion derived from the nitrogen atom-containing monomer in the higher-order structure of the pressure-sensitive adhesive, the nitrogen atom-containing monomer forms the (meth)acrylic acid ester polymer (A). preferably contains no reactive unsaturated double bond groups other than the one polymerizable group used in the polymerization of .

Examples of monomers having a nitrogen-containing heterocyclic ring include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloyl pyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N-(meth)acryloylmorpholine, which exhibits superior adhesive strength, is preferred, and N-acryloylmorpholine 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 polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, it preferably contains 1 mass% or more of the nitrogen atom-containing monomer, particularly 2 mass. % or more, more preferably 4 mass % or more. In addition, the (meth)acrylic acid ester polymer (A) preferably contains 24% by mass or less of the nitrogen atom-containing monomer, and particularly 16% by mass or less, as a monomer unit constituting the polymer. It is preferably contained in an amount of 8% by mass or less. When the content of the nitrogen atom-containing monomer is within the above range, the resulting pressure-sensitive adhesive can sufficiently exhibit excellent adhesive strength to glass.

The (meth)acrylic acid ester polymer (A) may optionally contain other monomers as monomer units constituting the polymer. As other monomers, monomers containing no reactive functional group are preferred so as not to inhibit the above-described effects of the reactive functional group-containing monomer. Examples of such monomers include alkoxyalkyl (meth)acrylates 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 (meth)acrylate polymer (A) is preferably a linear polymer. Being a straight-chain polymer facilitates the entanglement of molecular chains, which can be expected to improve cohesive strength. Therefore, it is possible to obtain a pressure-sensitive adhesive with excellent unevenness conformability and blister resistance under high-temperature and high-humidity conditions. easy.

Moreover, the (meth)acrylate polymer (A) is preferably a solution polymer obtained by a solution polymerization method. Since it is a solution polymer, it is easy to obtain a polymer with a high molecular weight, and improvement in cohesive strength can be expected, so it is easy to obtain a pressure-sensitive adhesive with excellent unevenness conformability and blister resistance under high-temperature and high-humidity conditions. .

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

The weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, particularly preferably 400,000 or more, as a lower limit, and coloring From the viewpoint of dispersibility of the agent (C), it is more preferably 500,000 or more. When the lower limit of the weight-average molecular weight of the (meth)acrylic acid ester polymer (A) is the above, the obtained pressure-sensitive adhesive tends to have suitable values such as gel fraction and storage elastic modulus, and can be used under high temperature and high humidity conditions. The unevenness followability and blister resistance under the surface are more excellent. In addition, there is a tendency that the dispersibility of the colorant (C) in the pressure-sensitive adhesive can be improved. can be easily controlled to a desired value.

In addition, the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 1,500,000 or less, more preferably 1,200,000 or less, and particularly preferably 1,000,000 or less as an upper limit. , and more preferably 800,000 or less. When the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is the above, the obtained pressure-sensitive adhesive tends to have suitable values such as the gel fraction and storage elastic modulus, and the initial unevenness follows. It will have better properties. The weight average molecular weight in this specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

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

(1-2) Crosslinking agent (B)
The cross-linking agent (B) cross-links the (meth)acrylic acid ester polymer (A) by heating the pressure-sensitive adhesive composition P, making it possible to satisfactorily form a three-dimensional network structure. As a result, the cohesive force of the obtained pressure-sensitive adhesive is improved, and the unevenness followability and blistering resistance under high-temperature and high-humidity conditions are excellent.

The cross-linking agent (B) may be one that reacts with the reactive groups of the (meth)acrylic acid ester polymer (A). Examples include isocyanate cross-linking agents, epoxy cross-linking agents, and amine cross-linking agents. , melamine cross-linking agent, aziridine cross-linking agent, hydrazine cross-linking agent, aldehyde cross-linking agent, oxazoline cross-linking agent, metal alkoxide cross-linking agent, metal chelate cross-linking agent, metal salt cross-linking agent, ammonium salt cross-linking agent, etc. is mentioned. Among the above, when the reactive group of the (meth)acrylic acid ester polymer (A) is a hydroxyl group, it is preferable to use an isocyanate-based cross-linking agent having excellent reactivity with the hydroxyl group. When the reactive group possessed by the polymer (A) is a carboxy group, it is preferable to use an epoxy-based cross-linking agent having excellent reactivity with the carboxy group. Further, when a hydroxyl group and a carboxy group coexist as reactive groups possessed by the (meth)acrylic acid ester polymer (A), an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent may be used in combination. Only those cross-linking agents that are preferred for the high content of reactive groups in the acid ester polymer (A) may be used. In addition, a crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

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

Examples of epoxy-based cross-linking agents include 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether. , 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine and the like. Among them, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane is preferable from the viewpoint of reactivity with carboxy groups.

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.01 parts by mass or more, particularly 0.01 part by mass, based on 100 parts by mass of the (meth)acrylic acid ester polymer (A). 05 parts by mass or more, and more preferably 0.1 parts by mass or more. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.4 parts by mass or less. is preferred, and 0.2 parts by mass or less is most preferred. When the content of the cross-linking agent (B) is within the above range, the gel fraction, storage elastic modulus, adhesive strength, etc. of the resulting pressure-sensitive adhesive tend to be suitable, and the conformability to irregularities under high-temperature and high-humidity conditions and Better blister resistance.

(1-3) Colorant (C)
The coloring agent (C) may be a pigment or a dye. The pigment may be an inorganic pigment or an organic pigment. Inorganic pigments are preferred from the viewpoint of the durability of the pressure-sensitive adhesive to be obtained. The color of the coloring agent can be appropriately selected depending on the purpose. For example, if you want to create a sense of unity with the peripheral member, you can select the color according to the color of the peripheral member. Generally, dark or deep colors such as black, brown, navy blue, purple, and blue are used. is preferred, and black is particularly preferred.

Examples of inorganic pigments include carbon black pigments, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, and ITO. (indium tin oxide) dyes, ATO (antimony tin oxide) dyes, and the like.

Examples of organic pigments and organic dyes include aminium dyes, cyanine dyes, merocyanine dyes, croconium dyes, squalium dyes, azulenium dyes, polymethine dyes, naphthoquinone dyes, pyrylium dyes, Phthalocyanine dyes, naphthalocyanine dyes, naphtolactam dyes, azo dyes, condensed azo dyes, indigo dyes, perinone dyes, perylene dyes, dioxazine dyes, quinacridone dyes, isoindolinone dyes, quinophthalone dyes Dyes, pyrrole dyes, thioindigo dyes, metal complex dyes (metal complex salt dyes), dithiol metal complex dyes, indolephenol dyes, triallylmethane dyes, anthraquinone dyes, dioxazine dyes, naphthol dyes, azomethine dyes, benzimidazolone dyes, pyranthrone dyes, and threne dyes.

Examples of black pigments include carbon black, copper oxide, triiron tetraoxide, manganese dioxide, aniline black, and activated carbon. Black dyes include, for example, high-concentration vegetable dyes and azo dyes.

Incidentally, the above pigments or dyes can be appropriately mixed and used according to the purpose.

Among the above colorants, carbon black pigments, nigrosine black dyes, and chromate black dyes are preferable from the viewpoint of facilitating a sense of unity with peripheral members. The surface of the carbon black may or may not be subjected to a predetermined treatment (for example, a solvent-affinity treatment).

The coloring agent has a lower limit of 1% or more of the average haze value, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, in a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate. is preferred, particularly preferably 2% or more, more preferably 3% or more. The upper limit of the average haze of the coloring agent is preferably 60% or less, preferably 40% or less, particularly preferably 30% or less, and further preferably 20% or less. is preferred, and 10% or less is most preferred. By using an appropriate amount of such a colorant, the resulting colored adhesive layer 111 has suitable optical properties, and therefore the resulting adhesive layer 11 tends to have suitable optical properties.

Further, the colorant preferably has a difference value of 30 points or less between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm in a solution obtained by diluting the colorant 10,000 times with ethyl acetate. A score of 25 points or less is more preferable, a score of 20 points or less is particularly preferable, a score of 16 points or less is more preferable, and a score of 10 points or less is most preferable. By using an appropriate amount of such a colorant, the resulting colored adhesive layer 111 has suitable optical properties, and therefore the resulting adhesive layer 11 tends to have suitable optical properties.

The lower limit of the difference in haze value may be 0 point, but it is 0.1 point or more from the viewpoint of easily adjusting the optical properties of the colored pressure-sensitive adhesive layer 111 described above. 0.5 points or more is more preferable, 1 point or more is particularly preferable, and 3 points or more is more preferable.

The haze value at a wavelength of 780 nm of a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is preferably 0.1 to 50%, more preferably 0.5 to 40%, and particularly 1 to 50%. It is preferably 30%, more preferably 1.5-20%, most preferably 2-10%. Further, the haze value at a wavelength of 380 nm of a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is preferably 1 to 60%, more preferably 3 to 50%, and particularly 6 to 40%. is preferably 8 to 30%, most preferably 10 to 20%. This makes it easier to satisfy the above difference in haze value.

Furthermore, a standard haze value of a solution obtained by diluting the colorant 10,000 times with ethyl acetate at each wavelength of 5 nm pitch in the wavelength range of 380 nm to 780 nm (that is, 380 nm, 385 nm, 390 nm, ..., 775 nm, 780 nm) The deviation is preferably 10 or less, more preferably 8 or less, particularly preferably 5 or less, further preferably 2 or less. The lower limit of the standard deviation is most preferably 0, but usually preferably 0.1 or more, particularly preferably 0.5 or more, and further preferably 1 or more. . Thereby, the optical properties of the colored pressure-sensitive adhesive layer 111 to be obtained are favorable, and therefore the optical properties of the pressure-sensitive adhesive layer 11 to be obtained are likely to be favorable.

In the colored pressure-sensitive adhesive layer 111, the content of the colorant (C) with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A) makes it easy to control the total light transmittance to a desired value, and From the viewpoint of easily exhibiting excellent hiding properties when turned off, the amount is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and particularly preferably 0.1 parts by mass or more. It is preferably 0.3 parts by mass or more, and more preferably 0.4 parts by mass or more. In addition, the above content is 8 parts by mass or less from the viewpoint that it becomes easy to control the haze to a desired value and it becomes easy to exhibit excellent visibility (easy to see images and videos) when the display is lit. preferably 4 parts by mass or less, particularly preferably 2 parts by mass or less, and further preferably 1 part by mass or less. When the content of the coloring agent (C) is within the above range, the pressure-sensitive adhesive obtained can be sufficiently colored without deteriorating the durability and the like, and the desired concealability and visibility can be exhibited. In this specification, the term "concealability" means that when the display is turned off, the appearance of the display portion of the display and the peripheral members such as the frame-like printed layer and the frame material are in harmony, and the boundaries between them are harmonized. It means to become invisible.

(1-4) Active energy ray-curable component (D)
When the adhesive constituting the colored adhesive layer 111 or the colorless adhesive layer 112 is an active energy ray-curable adhesive, the adhesive composition P contains an active energy ray-curable component (D). is preferred. In the adhesive obtained by curing the adhesive obtained by cross-linking the adhesive composition P with an active energy ray, the active energy ray-curable component (D) is polymerized with each other, and the polymerized active energy ray-curable component (D) is It is presumed to be entwined with the crosslinked structure (three-dimensional network structure) of the (meth)acrylic acid ester polymer (A). A pressure-sensitive adhesive having such a high-order structure exhibits extremely excellent durability, and is particularly excellent in conformability to irregularities and resistance to blistering under high-temperature and high-humidity conditions.

The active energy ray-curable component (D) is not particularly limited as long as it is a component that cures by irradiation with an active energy ray and provides the above effects, and may be any of monomers, oligomers or polymers. may be a mixture of Among them, polyfunctional acrylate-based monomers, which are more excellent in blister resistance, are preferred.

Examples of polyfunctional acrylate monomers 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 hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, tricyclodecanedimethanol (meth)acrylate, caprolactone-modified dicyclopentenyl di( meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2- Bifunctional type such as acryloyloxyethoxy)phenyl]fluorene; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate , propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl) isocyanurate; diglycerin tetra ( Tetrafunctional type such as meth)acrylate and pentaerythritol tetra(meth)acrylate; Pentafunctional type such as propionic acid-modified dipentaerythritol penta(meth)acrylate; Dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa( Hexafunctional type such as meth)acrylate and the like can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type. From the viewpoint of compatibility with the (meth)acrylic acid ester polymer (A), the polyfunctional acrylate monomer preferably has a molecular weight of less than 1,000.

Among the above, di(acryloxyethyl) isocyanurate, tris(acryloxyethyl) isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl), from the viewpoint of blister resistance of the obtained pressure-sensitive adhesive Polyfunctional acrylate monomers containing an isocyanurate structure in the molecule such as isocyanurate, or polyfunctional acrylate monomers containing a cyclic structure (especially cycloalkane structure) in the molecule such as tricyclodecanedimethanol (meth)acrylate is preferred, and a polyfunctional acrylate monomer containing a trifunctional or higher and an isocyanurate structure in the molecule, or a polyfunctional or higher and a polycyclic structure (especially a polycyclic structure of cycloalkane) in the molecule Functional acrylate-based monomers are more preferred, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate or tricyclodecanedimethanol (meth)acrylate is particularly preferred, and ε-caprolactone-modified tris-(2-acrylate More preferred are tricyclodecanedimethanol acrylate and ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate.

The content of the active energy ray-curable component (D) in the adhesive composition P is determined under high-temperature and high-humidity conditions, with the gel fraction and storage elastic modulus of the adhesive after active energy ray-curing being preferred. From the viewpoint of further improving the conformability and blistering resistance under the surface, the lower limit is preferably 1 part by mass or more with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). , is particularly preferably 3 parts by mass or more, and more preferably 4 parts by mass or more. On the other hand, the upper limit of the content is preferably 20 parts by mass or less, particularly preferably 12 parts by mass or less, and 8 parts by mass or less, from the viewpoint of the adhesive strength of the adhesive after curing with active energy rays. is more preferable.

(1-5) Photopolymerization initiator (E)
When ultraviolet rays are used as active energy rays for curing the adhesive composition P, the 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 (D) can be efficiently polymerized, and the polymerization curing time and the irradiation dose of the active energy ray can be reduced. can.

Examples of such photoinitiators (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 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-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4 ,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and the like. These may be used alone or in combination of two or more.

Among the above, phosphine oxide-based photopolymerization initiators are preferable because they are easily cleaved and easily cure the adhesive even when irradiated with ultraviolet rays through a plastic plate containing an ultraviolet absorber. Specifically, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and the like are preferred.

The content of the photopolymerization initiator (E) in the adhesive composition P is preferably 0.1 parts by mass or more as a lower limit with respect to 100 parts by mass of the active energy ray-curable component (D). In particular, it is preferably 1 part by mass or more, more preferably 5 parts by mass or more. Also, the upper limit is preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and further preferably 12 parts by mass or less.

The mass ratio of the amount of the photopolymerization initiator (E) to the amount of the colorant (C) (photopolymerization initiator (E)/colorant (C)) is preferably 0.1 or more, particularly 0.1. It is preferably 3 or more, more preferably 0.6 or more. Also, the mass ratio is preferably 10 or less, more preferably 5 or less, particularly preferably 2 or less, further preferably 1 or less. By setting the ratio of the amount of the photopolymerization initiator (E) to the amount of the colorant (D) within the above range, while controlling the total light transmittance and the haze value within the preferable range, more suitable active energy ray curing can be achieved. A pressure-sensitive adhesive having a gel fraction, storage modulus and adhesive strength is easily obtained, and is likely to be excellent in conformability to irregularities and resistance to blistering under high-temperature and high-humidity conditions.

(1-6) Various Additives The adhesive composition P may optionally contain various additives commonly used in acrylic adhesives, such as silane coupling agents, rust inhibitors, ultraviolet absorbers, and antistatic agents. , tackifiers, antioxidants, light stabilizers, softeners, refractive index modifiers and the like can be added. It should be noted that a polymerization solvent and a dilution solvent, which will be described later, are not included in the additives constituting the adhesive composition P.

The adhesive composition P preferably contains a silane coupling agent among the above. As a result, even if the adherend is a plastic plate or a glass member, the adhesion to the adherend is improved, and the conformability to irregularities and blister resistance under high-temperature and high-humidity conditions are better. It becomes a thing.

As the silane coupling agent, an organosilicon compound having at least one alkoxysilyl group in the molecule, having good compatibility with the (meth)acrylic acid ester polymer (A), and having optical transparency. preferable.

Such silane coupling agents include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane and like silicon compounds containing polymerizable unsaturated groups, 3-glycidoxypropyltrimethoxysilane, 2-( Silicon compounds having an epoxy structure such as 3,4-epoxycyclohexyl)ethyltrimethoxysilane, mercapto group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane , 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino group-containing silicon compounds, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these, and an alkyl group-containing silicon compound such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. and condensates of. 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 in the adhesive composition P is preferably 0.01 parts by mass or more, particularly 0.05 parts by mass, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A). It is preferably at least 0.1 part by mass, more preferably at least 0.1 part by mass. Also, the content is preferably 1.2 parts by mass or less, particularly preferably 0.8 parts by mass or less, and further preferably 0.4 parts by mass or less.

(2) Preparation of adhesive composition The adhesive composition P is produced by producing a (meth) acrylic acid ester polymer (A), the obtained (meth) acrylic acid ester polymer (A), and a cross-linking agent ( B) and, if desired, the active energy ray-curable component (D), the photopolymerization initiator (E), additives and the like are added. In the case of the colored adhesive layer 111, a coloring agent (C) is further blended.

The (meth)acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a conventional radical polymerization method. Polymerization of the (meth)acrylic acid ester polymer (A) is preferably carried out by a solution polymerization method, optionally using a polymerization initiator. However, the present invention is not limited to this, and may be polymerized without a solvent. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of polymerization initiators include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of azo compounds include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane 1-carbonitrile), 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 organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di(2-ethoxyethyl)peroxy dicarbonate, t-butylperoxyneodecanoate, t-butylperoxybivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionylperoxide, diacetylperoxide and the like.

The weight average molecular weight of the resulting polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol in the polymerization step.

After the (meth)acrylic acid ester polymer (A) is obtained, the solution of the (meth)acrylic acid ester polymer (A) is added with the cross-linking agent (B) and, if desired, a diluent solvent, a coloring agent (C), an active An energy ray-curable component (D), a photopolymerization initiator (E), additives and the like are added and thoroughly mixed to obtain a solvent-diluted adhesive composition P (coating solution). In any of the above components, if a solid one is used, or if precipitation occurs when mixed with other components in an undiluted state, the component is added alone in advance to a dilution solvent. It may be dissolved or diluted prior to mixing with other ingredients.

Examples of the diluting solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration/viscosity of the coating solution thus prepared is not particularly limited as long as it is within a range that allows coating, and can be appropriately selected according to the situation. For example, the adhesive composition P is diluted to a concentration of 10 to 60% by mass. When obtaining the coating solution, the addition of a diluent solvent or the like is not a necessary condition, and the diluent solvent may not be added as long as the viscosity of the adhesive composition P allows coating. In this case, the adhesive composition P becomes a coating solution in which the polymerization solvent for the (meth)acrylic acid ester polymer (A) is used as the diluting solvent.

(3) Formation of Adhesive Layer It is preferable that each of the colored adhesive layer 111 and the colorless adhesive layer 112 in the present embodiment is made of an adhesive obtained by cross-linking (the coating layer of) the adhesive composition P. Crosslinking of the adhesive composition P can usually be performed by heat treatment. This heat treatment can also serve as a drying treatment for volatilizing the diluent solvent from the coating layer of the adhesive composition P applied to the desired object.

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, more preferably 50 seconds to 2 minutes.

After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be provided at room temperature (eg, 23° C., 50% RH). If the curing period is required, the adhesive is formed after the curing period has elapsed, and if the curing period is not required, the adhesive is formed after the heat treatment is completed.

By the above heat treatment (and curing), the (meth)acrylate polymer (A) is sufficiently crosslinked via the crosslinking agent (B).

The adhesive layer 11 in this embodiment can be obtained by laminating the colored adhesive layer 111 and the colorless adhesive layer 112 . The timing of lamination may be before curing each pressure-sensitive adhesive layer or after curing. However, in order to increase the adhesion between the colored adhesive layer 111 and the colorless adhesive layer 112, it is preferable to laminate the adhesive layers before curing them.

(4) Physical Properties of Adhesive The adhesive in the present embodiment preferably has the following physical properties.
(4-1) Gel Fraction The lower limit of the gel fraction of both the colored adhesive layer 111 and the colorless adhesive layer 112 is preferably 20% or more, more preferably 40% or more. It is more preferably 50% or more, particularly preferably 52% or more. The upper limit of the gel fraction is preferably 100% or less, more preferably 80% or less, particularly preferably 70% or less, and further preferably 60% or less. , 55% or less. When the gel fraction of the pressure-sensitive adhesive is within the above range, the pressure-sensitive adhesive exhibits good cohesive force, and both conformability to irregularities and blister resistance under high-temperature and high-humidity conditions are excellent. . In addition, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent. Here, the method for measuring the gel fraction of the pressure-sensitive adhesive is as shown in the test examples described later.

In the case of an active energy ray-curable adhesive, the lower limit of the gel fraction of the adhesive after active energy ray curing is preferably 40% or more, more preferably 50% or more, and particularly 60%. It is preferably 65% or more, more preferably 65% or more. The upper limit of the gel fraction is preferably 100% or less, more preferably 90% or less, particularly preferably 80% or less, and further preferably 75% or less. , 71% or less. When the gel fraction of the pressure-sensitive adhesive after curing with active energy rays is within the above range, the uneven conformability and blistering resistance under high-temperature and high-humidity conditions are more excellent. In addition, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent.

(4-2) Storage Elastic Modulus The storage elastic modulus of the adhesive constituting the colored adhesive layer 111 at 23° C. is preferably 0.01 MPa or more as a lower limit, preferably 0.02 MPa or more. In particular, it is preferably 0.04 MPa or more, more preferably 0.06 MPa or more. By setting the lower limit of the storage elastic modulus to the above range, the blister resistance is excellent. Further, when the colorless adhesive layer 112 of the adhesive sheet 11 according to this embodiment is brought into contact with and follows the irregularities of the adherend, it is compressed or deformed due to the irregularities of the adherend. Due to this, the colored adhesive layer 111 may be affected by the compression or deformation of the colorless adhesive layer 112 (that is, uneven transmittance may occur), but the lower limit of the storage elastic modulus is As a result, the colored adhesive layer 111 is less likely to be affected by compression or deformation of the colorless adhesive layer 112, and the luminous flux transmittance, which will be described later, can be easily controlled to a desired value. As a result, the effect of suppressing unevenness in transmittance is more excellent.

The upper limit of the storage elastic modulus is preferably 1 MPa or less, more preferably 0.5 MPa or less, particularly preferably 0.2 MPa or less, and further preferably 0.1 MPa or less. . By setting the upper limit of the storage elastic modulus to the above range, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent.

On the other hand, the lower limit of the storage elastic modulus of the pressure-sensitive adhesive constituting the colorless pressure-sensitive adhesive layer 112 at 23° C. is preferably 0.01 MPa or more, particularly preferably 0.02 MPa or more, and further preferably 0.04 MPa. It is preferable that it is above. By setting the lower limit of the storage elastic modulus to the above range, excellent conformability to irregularities and resistance to blistering under high-temperature and high-humidity conditions are obtained.

The upper limit of the storage elastic modulus is preferably 1 MPa or less, more preferably 0.5 MPa or less, particularly preferably 0.2 MPa or less, and further preferably 0.1 MPa or less. , 0.05 MPa or less. By setting the upper limit of the storage elastic modulus to the above range, the initial conformability to irregularities is excellent. In addition, unevenness of the adherend can be absorbed by the colorless adhesive layer 112, and compression or deformation of the colored adhesive layer 111 due to the unevenness can be suppressed more effectively. As a result, the luminous flux transmittance and the like, which will be described later, can be controlled to desired values. Therefore, uneven transmittance in the pressure-sensitive adhesive layer 11 is more effectively suppressed.

When the adhesive constituting the colored adhesive layer 111 is an active energy ray-curable adhesive, the storage elastic modulus of the adhesive at 23° C. after being cured with active energy rays is 0.05 MPa or more as a lower limit. , more preferably 0.09 MPa or more, particularly preferably 0.12 MPa or more, further preferably 0.15 MPa or more. By setting the lower limit of the storage elastic modulus to the above range, the blister resistance is excellent. The upper limit of the storage elastic modulus is preferably 2 MPa or less, more preferably 1 MPa or less, particularly preferably 0.5 MPa or less, and further preferably 0.2 MPa or less. . By setting the upper limit of the storage elastic modulus to the above range, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent.

On the other hand, when the adhesive constituting the colorless adhesive layer 112 is an active energy ray-curable adhesive, the storage elastic modulus of the adhesive at 23° C. after being cured with the active energy ray is 0.05 MPa or more as a lower limit. It is preferably 0.08 MPa or more, and more preferably 0.12 MPa or more. By setting the lower limit of the storage elastic modulus to the above range, excellent conformability to irregularities and resistance to blistering under high-temperature and high-humidity conditions are obtained. The upper limit of the storage elastic modulus is preferably 2 MPa or less, more preferably 1 MPa or less, particularly preferably 0.5 MPa or less, and further preferably 0.2 MPa or less. . By setting the upper limit of the storage elastic modulus to the above range, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent.

When G1 is the storage modulus at 23° C. of the pressure-sensitive adhesive that constitutes the colored pressure-sensitive adhesive layer 111 and G2 is the storage modulus of the pressure-sensitive adhesive that constitutes the colorless pressure-sensitive adhesive layer 112 at 23° C., G1 and G2 are given below. It is preferable to satisfy the relational expression.
G1≧G2
By satisfying the above relational expression, when the colorless adhesive layer 112 of the adhesive sheet 11 according to the present embodiment is brought into contact with and follows the unevenness of the adherend, the colorless adhesive layer 112 is colorless due to the unevenness of the adherend. The colored adhesive layer 111 is less likely to be affected by the compression or deformation of the agent layer 112, and the luminous flux transmittance, which will be described later, can be easily controlled to a desired value. It becomes a thing. From this point of view, G1 and G2 more preferably satisfy the following relational expression.
G1 > G2

The storage elastic modulus in this specification is a value measured by a torsional shear method at a measurement frequency of 1 Hz in accordance with JIS K7244-6. Specifically, it is as shown in the test examples described later.

(5) Thickness of Adhesive Layer The thickness of the colored adhesive layer 111 may be any thickness that provides desired optical properties (including the degree of coloring), but the lower limit is usually 5 μm or more. It is preferably 20 μm or more, particularly preferably 40 μm or more, further preferably 50 μm or more. When the lower limit of the thickness of the colored pressure-sensitive adhesive layer 111 is within the above range, it is easy to obtain desired optical properties and to exhibit desired adhesive strength in relation to the content of the colorant (C).

The upper limit of the thickness of the colored adhesive layer 111 is preferably 200 μm or less, more preferably 150 μm or less, particularly preferably 100 μm or less, and further preferably 75 μm or less. . When the upper limit of the thickness of the colored adhesive layer 111 is above, the thickness of the adhesive layer 11 is likely to be suitable. In addition, desired optical properties can be easily obtained depending on the content of the coloring agent (C) and the like. Note that the colored adhesive layer 111 may be formed as a single layer, or may be formed by laminating a plurality of layers.

On the other hand, the thickness of the colorless pressure-sensitive adhesive layer 112 (the colorless pressure-sensitive adhesive layer located on the surface in contact with the irregularities of the adherend) is preferably larger than the depth or height of the irregularities of the adherend, as described above. . Normally, the lower limit is preferably 10 μm or more, more preferably 30 μm or more, particularly preferably 40 μm or more, and further preferably 50 μm or more. When the lower limit value of the thickness of the colorless adhesive layer 112 is above, the unevenness of the adherend can be absorbed by the colorless adhesive layer 112, and the colored adhesive layer 111 is compressed or deformed by the unevenness. is more effectively suppressed. This makes it easier to control the luminous flux transmittance and the like, which will be described later, to desired values. Therefore, uneven transmittance in the pressure-sensitive adhesive layer 11 is more effectively suppressed.

The upper limit of the thickness of the colorless adhesive layer 112 is preferably 300 μm or less, more preferably 200 μm or less, particularly preferably 100 μm or less, and further preferably 75 μm or less. . When the upper limit of the thickness of the colorless adhesive layer 112 is above, the thickness of the adhesive layer 11 tends to be suitable. Note that the colorless adhesive layer 112 may be formed as a single layer, or may be formed by laminating a plurality of layers.

Here, the thickness of the colorless pressure-sensitive adhesive layer that is not located on the surface of the adherend that contacts the irregularities is not limited to the above range, and can be set to a desired thickness.

The thickness of the pressure-sensitive adhesive layer 11 can be appropriately set according to its use, but usually the lower limit is preferably 50 μm or more, more preferably 80 μm or more, and particularly 100 μm or more. It is preferably 150 μm or more, more preferably 150 μm or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is within the above range, it becomes easier to obtain desired adhesive strength and excellent followability to irregularities.

The upper limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 500 μm or less, more preferably 300 μm or less, particularly preferably 250 μm or less, further preferably 200 μm or less. When the upper limit value of the thickness of the pressure-sensitive adhesive layer 11 is within the above range, workability is improved, and defects in appearance such as impressions are less likely to occur.

1-2. Release Sheet The release sheets 12a and 12b protect the adhesive layer 11 until the adhesive sheet 1 is used, and are peeled off when the adhesive sheet 1 (adhesive layer 11) is used. In the adhesive sheet 1 according to this embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and 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, fluorine A resin film or the like is used. Crosslinked films of these are also used. Furthermore, a laminated film of these may be used.

The release surfaces of the release sheets 12a and 12b (especially the surfaces in contact with the pressure-sensitive adhesive layer 11) are preferably subjected to a release treatment. Examples of release agents 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, the release sheet on the side to be released first from the adhesive layer 11 is a light release type release sheet with a small release force, and the release sheet on the side to be released later is a heavy release type with a large release force. A release sheet is preferred.

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

2. Physical properties (1) Total light transmittance The total light transmittance of the colored adhesive layer 111 (value measured in accordance with JIS K7361-1:1997; the same shall apply hereinafter) is preferably 3% or more as a lower limit. , preferably 10% or more, particularly preferably 30% or more, further preferably 45% or more. When the colored pressure-sensitive adhesive layer 111 has the above total light transmittance, visibility as a display body is easily ensured. On the other hand, the upper limit of the total light transmittance of the colored pressure-sensitive adhesive layer 111 is not particularly limited, but it is usually 100% or less, preferably 90% or less, and 80% or less in consideration of concealability. is more preferable, particularly preferably 70% or less, and further preferably 60% or less.

The total light transmittance of the colorless pressure-sensitive adhesive layer 112 is preferably 80% or more, more preferably 90% or more, particularly preferably 95% or more, further preferably 99% or more. preferable. When the total light transmittance of the colorless pressure-sensitive adhesive layer 112 is above, the transparency is high, and the pressure-sensitive adhesive layer 11 is suitable for optical applications (for displays). In addition, when the colorless adhesive layer 112 is compressed or deformed due to the unevenness of the adherend, it is easy to maintain high transparency even in the vicinity of the unevenness. can be easily controlled to the value of , and the effect of suppressing the unevenness of the transmittance is excellent. Although the upper limit of the total light transmittance of the colorless adhesive layer 112 is not particularly limited, it is usually 100% or less.

The lower limit of the total light transmittance of the adhesive layer 11 is preferably 3% or more, more preferably 10% or more, particularly preferably 30% or more, and further preferably 40% or more. is preferred. By setting the total light transmittance of the pressure-sensitive adhesive layer 11 to the above range, the visibility as a display is good. On the other hand, the upper limit of the total light transmittance of the pressure-sensitive adhesive layer 11 is not particularly limited, but it is usually 100% or less, preferably 90% or less, and 75% or less from the viewpoint of good hiding properties. It is more preferably 65% or less, and more preferably 55% or less.

When the adhesive layer is active energy ray-curable, the total light transmittance of the adhesive layer does not substantially change between before and after active energy ray curing.

(2) Haze value The haze value of the colored pressure-sensitive adhesive layer 111 (value measured according to JIS K7136:2000; the same shall apply hereinafter) is preferably 0.5% or more, and preferably 1% or more as a lower limit. is preferably 1.6% or more, and more preferably 2.2% or more. By setting the haze value of the colored pressure-sensitive adhesive layer 111 to the above range, it is easy to obtain a desired degree of coloring. For example, it is easy to impart a sense of unity with a peripheral member (for example, a frame member) to the obtained display body, and it is excellent in concealability. On the other hand, the upper limit of the haze value of the colored adhesive layer 111 is preferably 60% or less, preferably 40% or less, particularly preferably 25% or less, further preferably 10% or less. is preferred. By setting the haze value of the colored pressure-sensitive adhesive layer 111 to the above range, the visibility as a display is good.

The upper limit of the haze value of the colorless adhesive layer 112 is preferably 10% or less, preferably 1% or less, particularly preferably 0.5% or less, and further preferably 0.2%. The following are preferable. When the haze value of the colorless pressure-sensitive adhesive layer 112 is above, the transparency is high and the pressure-sensitive adhesive layer 11 is suitable for optical applications (for display). In addition, the haze value of the colorless adhesive layer 112 is usually 0% or more as a lower limit.

The upper limit of the haze value of the adhesive layer 11 is preferably 60% or less, preferably 40% or less, particularly preferably 25% or less, and further preferably 10% or less. . By setting the haze value of the pressure-sensitive adhesive layer 11 to the above range, the visibility as a display is good. On the other hand, considering the presence of the colored adhesive layer 111, the lower limit of the haze value of the adhesive layer 11 is preferably 0.1% or more, preferably 1% or more, and particularly 2% or more. preferably 2.5% or more. As a result, a desired degree of coloring can be easily obtained, and for example, a sense of unity with the peripheral member (for example, frame member) can be easily imparted to the display body.

When the adhesive layer is active energy ray-curable, the haze value of the adhesive layer does not substantially change between before and after active energy ray curing.

The optical physical properties described above can be achieved by appropriately selecting the type and content of the colorant (C) contained in the pressure-sensitive adhesive forming the colored pressure-sensitive adhesive layer 111 .

(3) Adhesive strength The lower limit of the adhesive strength of the colored adhesive layer 111 to soda lime glass is preferably 10 N/25 mm or more, more preferably 20 N/25 mm or more, and 30 N/25 mm or more. is particularly preferable, and 40 N/25 mm or more is more preferable. When the lower limit of the adhesive strength is above, the blister resistance is excellent. The upper limit of the adhesive strength of the colored adhesive layer 111 to soda lime glass is preferably 90 N/25 mm or less, more preferably 70 N/25 mm or less, and particularly preferably 50 N/25 mm or less. . When the upper limit of the adhesive strength is above, good reworkability can be obtained, and in the event of a lamination error, it becomes possible to reuse display body constituent members, especially expensive display body constituent members.

When the adhesive constituting the colored adhesive layer 111 is an active energy ray-curable adhesive, the adhesive strength of the colored adhesive layer 111 after active energy ray curing is preferably 20 N/25 mm or more as a lower limit. , 30 N/25 mm or more, and more preferably 40 N/25 mm or more. When the lower limit of the adhesive strength is above, the blister resistance is excellent. In addition, the upper limit of the adhesive strength of the colored adhesive layer 111 to soda lime glass after curing with active energy rays is preferably 100 N/25 mm or less, more preferably 75 N/25 mm or less, and 50 N/25 mm or less. is particularly preferred. When the upper limit of the adhesive strength is above, good reworkability can be obtained, and in the event of a lamination error, it becomes possible to reuse display body constituent members, especially expensive display body constituent members.

The lower limit of the adhesive strength of the colorless adhesive layer 112 to soda lime glass is preferably 10 N/25 mm or more, more preferably 20 N/25 mm or more, particularly preferably 30 N/25 mm or more, and 40 N. /25 mm or more is more preferable. When the lower limit of the adhesive strength is above, the conformability to irregularities under high-temperature and high-humidity conditions is excellent. The upper limit of the adhesive strength of the colorless adhesive layer 112 to soda lime glass is preferably 90 N/25 mm or less, more preferably 70 N/25 mm or less, and particularly preferably 50 N/25 mm or less. . Favorable reworkability is obtained as the upper limit of adhesive force is the above.

When the adhesive constituting the colorless adhesive layer 112 is an active energy ray-curable adhesive, the adhesive strength of the colorless adhesive layer 112 after curing with active energy rays to soda lime glass is 20 N/25 mm or more as a lower limit. It is preferably 30 N/25 mm or more, particularly preferably 40 N/25 mm or more, further preferably 40 N/25 mm or more. When the lower limit of the adhesive strength is above, the uneven conformability and blister resistance under high temperature and high humidity conditions are excellent. The upper limit of the adhesive strength of the colorless adhesive layer 112 to soda lime glass after curing with active energy rays is preferably 100 N/25 mm or less, more preferably 75 N/25 mm or less, and 50 N/25 mm or less. is particularly preferred. Favorable reworkability is obtained as the upper limit of adhesive force is the above.

The adhesive force of the adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 10 N/25 mm or more as a lower limit, more preferably 20 N/25 mm or more, and particularly 30 N/25 mm or more. Preferably, it is more preferably 40 N/25 mm or more. When the lower limit of the adhesive strength is above, the uneven conformability and blister resistance under high temperature and high humidity conditions are excellent. In addition, the upper limit of the adhesive strength of the adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 90 N/25 mm or less, more preferably 70 N/25 mm or less, and particularly 60 N/25 mm or less. is preferable, and more preferably 50 N/25 mm or less. When the upper limit of the adhesive strength is above, good reworkability can be obtained, and in the event of a lamination error, it becomes possible to reuse display body constituent members, especially expensive display body constituent members.

When the adhesive constituting the colored adhesive layer 111 or the colorless adhesive layer 112 is an active energy ray-curable adhesive, the adhesive strength of the adhesive sheet 1 after curing with active energy rays to soda lime glass is 20 N as a lower limit. /25 mm or more, particularly preferably 30 N/25 mm or more, and more preferably 40 N/25 mm or more. When the lower limit of the adhesive strength is above, the uneven conformability and blister resistance under high temperature and high humidity conditions are excellent. In addition, the upper limit of the adhesive strength of the adhesive sheet 1 to soda lime glass after curing with active energy rays is preferably 100 N/25 mm or less, more preferably 75 N/25 mm or less, and particularly 65 N/25 mm or less. It is preferably 55 N/25 mm or less. When the upper limit of the adhesive strength is above, good reworkability can be obtained, and in the event of a lamination error, it becomes possible to reuse display body constituent members, especially expensive display body constituent members.

Here, the adhesive strength in this specification basically refers to the adhesive strength measured by the 180 degree peeling method according to JIS Z0237: 2009, but the measurement sample has a width of 25 mm and a length of 100 mm. It is attached to an adherend, pressurized at 0.5 MPa and 50° C. for 20 minutes, then left under normal pressure, 23° C. and 50% RH for 24 hours, and then measured at a peel rate of 300 mm/min. shall be

(4) Unevenness followability The ability of the pressure-sensitive adhesive layer to conform to the unevenness of the adherend, that is, the unevenness followability can be determined using the unevenness followability rate (%) as an indicator. The colorless pressure-sensitive adhesive layer 112 preferably has a lower limit of 20% or more, more preferably 30% or more, and further preferably 40% or more in the irregularity conformance rate (%) represented by the following formula. is preferred. The upper limit of the irregularity follow-up rate is not particularly limited, but is usually preferably 80% or less, and particularly preferably 70% or less.

On the other hand, the irregularity follow-up rate (%) of the colored adhesive layer 111 does not need to be as high as the irregularity follow-up rate of the colorless adhesive layer 112, but the lower limit is preferably 20% or more, particularly 30% or more. preferably 40% or more. The upper limit of the irregularity follow-up rate is not particularly limited, but is usually preferably 80% or less, and particularly preferably 70% or less.

Unevenness follow-up rate (%) = {(height of step maintained in buried state without air bubbles, floating, peeling, etc. after predetermined durability test (μm)) / (thickness of adhesive layer)} x 100
The test method for the unevenness followability rate is as shown in the test examples to be described later. In the case of an active energy ray-curable pressure-sensitive adhesive, it is assumed to be the irregularity follow-up rate when the active energy ray is cured after sticking to the adherend.

3. Manufacture of Adhesive Sheet As an example of manufacturing the adhesive sheet 1, a coating solution of the adhesive composition P for forming the colorless adhesive layer 112 is applied to the release surface of one of the release sheets 12a, followed by heat treatment. Then, the adhesive composition P is thermally crosslinked to form a coating layer, thereby obtaining a release sheet 12a with a coating layer. Further, a coating solution of the adhesive composition P for forming the colored adhesive layer 111 is applied to the release surface of the other release sheet 12b, heat-treated to thermally crosslink the adhesive composition P, and applied. Layers are formed to obtain a release sheet 12b with a coating layer. Then, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are pasted together so that both coating layers are in contact with each other. Here, a plurality of release sheets with coating layers may be prepared, and the coating layers may be pasted together in a desired number and in a desired lamination order. When a curing period is required, the curing period is set, and when the curing period is not required, the laminated coating layer becomes the adhesive layer 11 as it is. As a result, the pressure-sensitive adhesive sheet 1 having the pressure-sensitive adhesive layer 11 which is a laminate of the colored pressure-sensitive adhesive layer 111 and the colorless pressure-sensitive adhesive layer 112 is obtained. The conditions for heat treatment and curing are as described above.

The coating layer for forming the colorless adhesive layer 112 and the coating layer for forming the colored adhesive layer 111 may each be held between two release sheets to form the colorless adhesive layer 112. When the coating layer for forming the colored adhesive layer 111 and the coating layer for forming the colored pressure-sensitive adhesive layer 111 are laminated, one of the release sheets may be peeled off.

As a method for applying the coating solution 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, or the like can be used.

[Display body]
Examples of the display (display) according to the present embodiment include an automobile instrument panel, a car navigation system, an in-vehicle display in various instruments provided in the console, a tablet terminal for general users, and the like. Examples thereof include displays, displays such as commercial tablet terminals and digital signage, and displays such as outdoor digital signage. These display bodies are sometimes required to have appearance harmony with peripheral members, high-class feeling, and the like. However, the display body according to the present invention is not limited to these.

As shown in FIG. 2, a display body 2A according to one embodiment includes a first display body constituting member 21 (one display body constituting member) and a second display body constituting member 22 (another display body constituting member). ) and the pressure-sensitive adhesive layer 11 positioned therebetween for adhering the first display body-constituting member 21 and the second display body-constituting member 22 to each other.

One of the first display body-constituting member 21 and the second display body-constituting member 22 may have an uneven surface on the side bonded by the pressure-sensitive adhesive layer 11 . In the embodiment shown in FIG. 2, the first display member constituting member 21 has unevenness due to the printed layer 23 on the surface on the pressure-sensitive adhesive layer 11 side.

The adhesive layer 11 in the display body 2A is the adhesive layer 11 of the adhesive sheet 1 described above. The pressure-sensitive adhesive layer 11 in this embodiment is a laminate of a colored pressure-sensitive adhesive layer 111 and a colorless pressure-sensitive adhesive layer 112 , and the colorless pressure-sensitive adhesive layer 112 is positioned on the side that contacts the unevenness of the printed layer 23 .

Examples of the display 2A 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.

The first display member constituting member 21 is preferably a protective panel made of a glass plate, a plastic plate or the like, or a laminated body including them. In this case, the printed layer 23 is generally formed in a frame shape on the adhesive layer 11 side of the first display member constituting member 21 .

The glass plate is not particularly limited, and examples thereof include chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium-strontium-containing glass, aluminosilicate glass, lead glass, borosilicate glass, and barium borosilicate. Glass etc. are mentioned. Although the thickness of the glass plate is not particularly limited, it is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

Examples of the plastic plate include, but are not limited to, an acrylic plate, a polycarbonate plate, and the like. Although the thickness of the plastic plate is not particularly limited, it is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

Various functional layers (a transparent conductive film, a metal layer, a silica layer, a hard coat layer, an antiglare layer, etc.) may be provided on one or both sides of the glass plate or the plastic plate. may be laminated. Moreover, the transparent conductive film and the metal layer may be patterned.

The second display body constituent member 22 includes an optical member to be attached to the first display body constituent member 21, a display body 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 part of a display module, or a laminate including a display module.

Examples of the optical member include anti-scattering films, polarizing plates (polarizing films), polarizers, retardation plates (retardation films), viewing angle compensation films, brightness enhancement films, contrast enhancement films, liquid crystal polymer films, and diffusion films. , transflective films, transparent conductive films, and the like. Examples of the anti-scattering film include a hard coat film in which a hard coat layer is formed on one side of a base film.

The material constituting the printing layer 23 is not particularly limited, and known materials for printing are used. The lower limit of the thickness of the printed layer 23, that is, the height of the step, is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. preferable. By setting the lower limit to the above range, it is possible to sufficiently secure the concealability, such as making the electrical wiring invisible to the viewer. The upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and even more preferably 20 μm or less. By setting the upper limit value to the above range, it is possible to prevent deterioration of the conformability of the pressure-sensitive adhesive layer 11 to the printed layer 23 against unevenness and to suppress unevenness in transmittance.

In order to manufacture the display body 2A, as an example, one release sheet 12a of the adhesive sheet 1 is peeled off, and the exposed colorless adhesive layer 112 of the adhesive sheet 1 is printed on the first display body constituent member 21. It is laminated on the side on which the layer 23 exists.

Thereafter, the other release sheet 12b is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the exposed colored adhesive layer 111 of the adhesive sheet 1 and the second display member constituting member 22 are bonded. As another example, the bonding order of the first display body forming member 21 and the second display body forming member 22 may be changed.

When the adhesive layer 11 is active energy ray-curable, after bonding the first display body constituent member 21 and the second display body constituent member 22 via the adhesive layer 11 as described above, The adhesive layer 11 is irradiated with active energy rays. As a result, the energy ray-curable component (C) in the adhesive layer 11 is polymerized and the adhesive layer 11 is cured. Irradiation of energy rays to the pressure-sensitive adhesive layer 11 is usually carried out through either the first display member constituting member 21 or the second display member constituting member 22, preferably through the first display member as a protective panel. It is carried out over the constituent member 21 .

The active energy ray refers to an electromagnetic wave or a charged particle beam that has energy quanta, and specifically includes ultraviolet rays, electron beams, and the like. Among active energy rays, ultraviolet rays are particularly preferable because they are easy to handle.

Ultraviolet irradiation can ^be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or ^the like. is preferably The amount of light is preferably 50 to 10000 mJ/cm ² , more preferably 200 to 7000 mJ/cm ² and particularly preferably 500 to 3000 mJ/cm ² . On the other hand, electron beam irradiation can be performed by an electron beam accelerator or the like, and the electron beam irradiation dose is preferably about 10 to 1000 krad.

In the display body 2A, the colorless adhesive layer 112 is laminated on the uneven surface of the printed layer 23 of the first display body constituent member 21, and the unevenness is absorbed by the colorless adhesive layer 112. , the colored adhesive layer 111 is suppressed from being compressed or deformed. As a result, uneven transmittance in the pressure-sensitive adhesive layer 11 is suppressed, and uneven brightness in the display 2A is suppressed.

In the display body 2A, when the pressure-sensitive adhesive layer 11 is formed from the pressure-sensitive adhesive composition P, the pressure-sensitive adhesive layer 11 has excellent unevenness conformability and blister resistance under high temperature and high humidity conditions, so the display Even when the body 2A is placed under high-temperature and high-humidity conditions (eg, 85° C., 85% RH), the occurrence of floating, peeling, etc. is suppressed.

As shown in FIG. 3, a display 2B according to another embodiment includes a backlight 30, an adhesive layer 11 laminated on the backlight 30, and a diffusion member 41 laminated on the adhesive layer 11. , and a liquid crystal panel 42 laminated on the diffusion member 41 . The backlight 30 in the display body 2B corresponds to a first display body constituent member, and the laminate including the diffusion member 41 and the liquid crystal panel 42 corresponds to a second display body constituent member.

The backlight 30 includes one or more substrates 31 and a plurality of light emitters 32 provided on the substrates 31 . The backlight 30 has unevenness due to a plurality of light emitters 32 .

The adhesive layer 11 in the display body 2B is the adhesive layer 11 of the adhesive sheet 1 described above. The adhesive layer 11 in this embodiment is a laminate of a colored adhesive layer 111 and a colorless adhesive layer 112 , and the colorless adhesive layer 112 is positioned on the side that contacts the unevenness of the light emitter 32 . The plurality of light emitters 32 are sealed without gaps by the colorless adhesive layer 112 . As a result, there are no air layers or gaps inside the obtained display body, so that deterioration in image quality due to reflection loss of light can be prevented.

The substrate 31 is not particularly limited, and substrates commonly used for backlights are used. This board 31 is usually a printed circuit board (PCB board).

The substrate 31 may be integrally formed so that a plurality of light emitters 32 are mounted together, or may be separately formed so that one light emitter 32 is mounted on one substrate 31 . may be formed. When formed separately, each substrate 31 is typically fixed to a frame, support, housing, or the like. In this embodiment, as shown in FIG. 3, the substrate 31 is preferably integrally formed so that a plurality of light emitters 32 are collectively mounted.

A reflective layer may be formed on the surface of the substrate 31 on the pressure-sensitive adhesive layer 11 side, or a reflective member may be provided. Thereby, the luminance of the backlight 30 can be effectively improved. Known materials can be used for the reflective layer and the reflective member.

Types of the light emitter 32 include, for example, a light emitting diode (LED), a laser diode (LD), an organic electroluminescence light emitting element, an inorganic electroluminescence light emitting element, and the like. Among these, LEDs are preferred, and mini-LEDs and micro-LEDs are particularly preferred, from the viewpoint of the sealing properties of the adhesive layer 11 .

The thickness of the light emitter 32 is preferably 10 μm or more, more preferably 30 μm or more, particularly preferably 50 μm or more, and further preferably 80 μm or more. Also, the thickness of the light emitter 32 is preferably 300 μm or less, particularly preferably 150 μm or less, further preferably 100 μm or less.

Also, the width of the gap between the light emitters 32 adjacent to each other is preferably 0.01 mm or more, particularly preferably 0.1 mm or more, further preferably 0.5 mm or more. The width of the gap is preferably 100 mm or less, more preferably 10 mm or less, particularly preferably 4 mm or less, and further preferably 2 mm or less.

Although the shape of the light emitter 32 is not particularly limited, it is usually rectangular parallelepiped, hemispherical, or the like. The size of the light emitter 32 is also not particularly limited, but from the viewpoint of sealing the light emitter, one side or diameter in plan view is preferably 0.01 to 100 mm, more preferably 0.1 to 10 mm. , particularly preferably 0.2 to 5 mm, more preferably 0.5 to 2 mm.

The diffusion member 41 is a member that diffuses the light emitted from the backlight 30, and the diffusion member 41 can effectively suppress the occurrence of luminance unevenness. The diffusion member 41 can employ a known member, such as a diffusion plate, a diffusion film, or a combination thereof. A known liquid crystal panel 42 can also be adopted.

A desired optical member is provided between the adhesive layer 11 and the diffusion member 41, between the diffusion member 41 and the liquid crystal panel 42, or on the surface of the liquid crystal panel 42 opposite to the diffusion member 41. may Such optical members include, for example, brightness enhancement films, contrast enhancement films, viewing angle compensation films, transparent conductive films, liquid crystal polymer films, transflective films, anti-scattering films and the like.

In order to manufacture the display body 2B according to the present embodiment, for example, one of the release sheets 12a of the adhesive sheet 1 is peeled off, and the exposed colorless adhesive layer 112 of the adhesive sheet 1 is replaced with the light emitter 32 of the backlight 30. is laminated on the side on which is present.

Next, the other release sheet 12b is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the exposed colored adhesive layer 111 of the adhesive sheet 1 and the diffusion member 41 are pasted together. When the adhesive layer 11 is active energy ray-curable, the adhesive layer 11 is irradiated with an active energy ray. The irradiation conditions and the like of the active energy ray are the same as in the case of the display 2A.

After that, using a desired adhesive sheet, the diffusion member 41 and the liquid crystal panel 42 are bonded together. As another example, the bonding order of the backlight 30 and the diffusion member 41 may be changed.

In the display body 2B, the colorless adhesive layer 112 is laminated on the uneven surface of the light emitter 32 in the backlight 30, and the unevenness is absorbed by the colorless adhesive layer 112. Therefore, the colored adhesive layer 111 is suppressed from being compressed or deformed. As a result, unevenness in transmittance in the pressure-sensitive adhesive layer 11 is suppressed, and unevenness in luminance in the display 2B is suppressed.

In the display body 2B, when the pressure-sensitive adhesive layer 11 is formed from the pressure-sensitive adhesive composition P, the pressure-sensitive adhesive layer 11 has excellent unevenness conformability and blister resistance under high temperature and high humidity conditions, so the display Even when the body 2B is placed under high-temperature and high-humidity conditions (eg, 85° C., 85% RH), the occurrence of floating, peeling, etc. is suppressed.

Here, the display body (including the display bodies 2A and 2B) in one embodiment of the present invention includes one display body constituting member, another display body constituting member, and an adhesive layer for bonding them together. At least one of the one display body component and the other display body component has an uneven surface on the side bonded by the adhesive layer, and the adhesive layer has at least one The ratio of the luminous flux transmittance in the vicinity of the unevenness to the luminous flux transmittance in the flat area (luminous flux transmittance in the vicinity of the unevenness/luminous flux transmittance in the flat area) is 0.5. It is preferably 980 or more, particularly preferably 0.986 or more, further preferably 0.990 or more. Most preferably, the upper limit is 1.

Further, the difference obtained by subtracting the light flux transmittance in the vicinity of the unevenness from the light flux transmittance in the flat part is preferably 1 point or less, more preferably 0.9 point or less, particularly 0.7. It is preferably not more than 0.5 points, more preferably not more than 0.5 points. Most preferably, the lower limit is 0 points.

When the display has the above-described configuration and physical properties, the transmittance unevenness is small, and therefore the occurrence of luminance unevenness in the display is suppressed. In addition, the above-mentioned “neighboring portion of unevenness” specifically refers to a portion within 10 mm in the plane direction from the position where there is a step due to unevenness. The above-mentioned "flat portion" refers to a portion that is sufficiently distant in the plane direction from the unevenness to the extent that it is not affected by the unevenness. Further, the above-mentioned "luminous flux transmittance" refers to the transmittance when the size of the transmitted light flux is 7 mmφ. A detailed method for measuring the luminous flux transmittance is as shown in the test examples described later.

The physical properties described above can be achieved by using the adhesive layer 11 of the adhesive sheet 1 described above as the adhesive layer. However, the present invention is not limited to this, and may be achieved with other pressure-sensitive adhesive layers.

The embodiments described above are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is meant to include all design changes and equivalents that fall within the technical scope of the present invention.

For example, one or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted, or a desired optical member may be laminated instead of the release sheets 12a and/or 12b.

Furthermore, like the adhesive sheet 1A shown in FIG. good. The pressure-sensitive adhesive sheet 1A is effective when both the first display body-constituting member and the second display body-constituting member have unevenness on the adhesive layer 11 side.

In addition, the adhesive layer 11 may be a laminate of a colorless adhesive layer 112 in which two layers are laminated and a colored adhesive layer 111, or may be a laminate of a colored adhesive layer 111 in which two layers are laminated and a colorless adhesive layer 111. The adhesive layer 112 may also be laminated.

EXAMPLES 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.

[Production Example 1] (Preparation of colored adhesive sheet)
1. Preparation of (meth)acrylate polymer 45 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of n-butyl acrylate, 10 parts by weight of isobornyl acrylate, 5 parts by weight of N-acryloylmorpholine and 20 parts by weight of 2-hydroxyethyl acrylate Parts by mass were copolymerized by a solution polymerization method to prepare a (meth)acrylic acid ester polymer (A). When the molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method described later, it was found to have a weight average molecular weight (Mw) of 600,000.

2. Preparation of adhesive composition 100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the above step 1 (solid content conversion value; the same applies hereinafter), and a trimethylolpropane-modified trimethylolpropane-modified trimethylolpropane 0.2 parts by mass of diisocyanate (manufactured by Toyochem, product name "BHS8515"), 0.6 parts by mass of a carbon black-based black pigment (C1) as a coloring agent (C), and an active energy ray-curable component (D ) as ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK Ester A-9300-1CL”) 5.0 parts by mass, and a photopolymerization initiator (E ) and 0.5 parts by mass of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as ) and 0.3 parts by mass of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and sufficiently The mixture was stirred at 100 rpm and diluted with methyl ethyl ketone to obtain a coating solution of the adhesive composition.

Here, Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth)acrylic acid ester polymer (A) is 100 parts by mass (solid content conversion value). Details of abbreviations and the like in Table 1 are as follows.
[(Meth) acrylic ester polymer (A)]
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate MMA: methyl methacrylate IBXA: isobornyl acrylate ACMO: N-acryloylmorpholine AA: acrylic acid HEA: 2-hydroxyethyl acrylate
[Colorant (C)]
C1-C2: Carbon black-based black pigments having physical properties shown in Table 2

A solution obtained by diluting C1 to C2 colorants 10,000 times with ethyl acetate is measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000", optical path length 10 mm) according to JIS K7136:2000. haze value (%) was measured. From the measured values, the difference (point) between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, the average haze (%) that is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, and the wavelength region The standard deviation of the haze value at each wavelength of 5 nm pitch from 380 nm to 780 nm was calculated. Each result is shown in Table 2.

3. Production of colored adhesive sheet The coating solution of the adhesive composition obtained in the above step 2 is applied to a polyethylene terephthalate film on one side of which is treated with a silicone-based release agent to release a heavy release type release sheet (manufactured by Lintec, product name "SP- PET752150") was coated with a knife coater and then heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 50 μm).

Next, the coating layer on the heavy release release sheet obtained above and a light release release sheet obtained by releasing a polyethylene terephthalate film on one side with a silicone release agent (manufactured by Lintec, product name "SP-PET381031"). are laminated so that the release-treated surface of the light-release release sheet is in contact with the coating layer, and the heavy-release release sheet/colored adhesive layer (a) (thickness: 50 μm)/light-release release sheet A colored pressure-sensitive adhesive sheet having the following structure was produced.

The thickness of the colored pressure-sensitive adhesive layer is a value measured using a constant-pressure thickness gauge (manufactured by Teclock, product name "PG-02") in accordance with JIS K7130 (hereinafter the same).

[Production Examples 2 to 5] (Preparation of colored adhesive sheet)
Type and proportion of each monomer constituting the (meth)acrylic acid ester polymer (A), weight average molecular weight (Mw) of the (meth)acrylic acid ester polymer (A), amount of cross-linking agent (B), coloration The type and amount of the agent (C), the amount of the active energy ray-curable component (D), the amount of the photopolymerization initiator (E), and the amount of the silane coupling agent were changed as shown in Table 1. Colored adhesive layer (b) (Production Example 2), colored adhesive layer (c) (Production Example 3), colored adhesive layer (d) (Production Example 4), and and a colored pressure-sensitive adhesive sheet having a colored pressure-sensitive adhesive layer (e) (manufacturing example 5).

The colored adhesive layer (b) prepared in Production Example 2 is made of an active energy ray non-curable adhesive, and the other colored adhesive layers (a), (c) to (e) are active It consisted of an energy ray-curable adhesive.

[Production Examples 6-7] (Preparation of colorless adhesive sheet)
Type and proportion of each monomer constituting the (meth)acrylic acid ester polymer (A), weight average molecular weight (Mw) of the (meth)acrylic acid ester polymer (A), amount of cross-linking agent (B), coloration Table 1 shows the compounding amount of the agent (C) (not compounded), the compounding amount of the active energy ray-curable component (D), the compounding amount of the photopolymerization initiator (E), and the compounding amount of the silane coupling agent. A colorless pressure-sensitive adhesive sheet having a colorless pressure-sensitive adhesive layer (f) (Production Example 6) and a colorless pressure-sensitive adhesive layer (g) (Production Example 7) was produced in the same manner as in Example 1 except for changing to .

The colorless pressure-sensitive adhesive layer (f) prepared in Production Example 6 is made of an active energy ray-curable pressure-sensitive adhesive, and the colorless pressure-sensitive adhesive layer (g) prepared in Production Example 7 is non-active energy ray-curable. It consisted of an adhesive.

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

[Example 1]
The light release type release sheet was peeled off from the colored pressure-sensitive adhesive sheet prepared in Production Example 1 to expose the colored pressure-sensitive adhesive layer (a). In addition, the light release type release sheets were peeled off from the two colorless pressure-sensitive adhesive sheets prepared in Production Example 6 to expose the first and second colorless pressure-sensitive adhesive layers (f). A first colorless pressure-sensitive adhesive layer (f) is laminated on the exposed colored pressure-sensitive adhesive layer (a), a heavy release release sheet is peeled off from the first colorless pressure-sensitive adhesive layer (f), and the first colorless pressure-sensitive adhesive layer (a) is The adhesive layer (f) was exposed. A second colorless pressure-sensitive adhesive layer (f) was laminated on the exposed first colorless pressure-sensitive adhesive layer (f). After that, it was cured for 7 days under conditions of 23° C. and 50% RH.

In this way, a heavy-release release sheet/colored adhesive layer (a) (first layer; 50 μm)/colorless adhesive layer (f) (second layer; 50 μm)/colorless adhesive layer (f) (second A pressure-sensitive adhesive sheet consisting of three layers (50 μm)/heavy release type release sheet was produced. The first layer is attached to a planar adherend, and the third layer is attached to an uneven adherend.

[Examples 2 to 9, Comparative Examples 1 to 3]
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive layers of the first, second and third layers were changed as shown in Table 4. In addition, only Example 8 was made into the adhesive layer which consists of a 1st layer and a 2nd layer.

[Test Example 1] (Measurement of gel fraction)
Cut the pressure-sensitive adhesive sheet prepared in each production example into a size of 80 mm × 80 mm, wrap the pressure-sensitive adhesive layer in a polyester mesh (mesh size 200), weigh the mass with a precision balance, and measure the mass of the mesh alone. By subtracting , the mass of the adhesive alone was calculated. Let the mass at this time be M1.

Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23° C.) for 24 hours. After that, the pressure-sensitive adhesive was taken out and 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 of 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. Let the mass at this time be M2. A gel fraction (%) is represented by (M2/M1)×100. From this, the gel fraction (before UV) of the adhesive was derived. Table 3 shows the results.

In addition, the adhesive layer of the adhesive sheets prepared in Production Examples 1 and 3 to 6 was irradiated with active energy rays (ultraviolet rays; UV) under the following conditions through the light release type release sheet to remove the adhesive layer. It was cured to form an adhesive layer after curing. For the adhesive of the cured adhesive layer, the gel fraction (after UV) was derived in the same manner as described above. Table 3 shows the results.

<Active energy ray irradiation conditions>
・Using a high-pressure mercury lamp ・Illuminance 200mW/cm ² , Light intensity 2000mJ/cm ²
・Using “UVPF-A1” manufactured by Eye Graphics Co., Ltd. for UV illuminance and photometer

[Test Example 2] (Measurement of storage modulus)
The release sheet was peeled off from the pressure-sensitive adhesive sheet produced in each production example, and a plurality of pressure-sensitive adhesive layers were laminated to a thickness of 3 mm. A cylinder with a diameter of 8 mm (height: 3 mm) was punched out from the resulting laminate of pressure-sensitive adhesive layers, and this was used as a sample.

For the above sample, in accordance with JIS K7244-6, by a torsional shear method using a viscoelasticity measuring device (manufactured by Physica, product name "MCR300"), the storage modulus at 23 ° C. (before UV; MPa ) was measured. Table 3 shows the results.
Measurement frequency: 1Hz
Measurement temperature: 23°C

In addition, for the adhesive sheets produced in Production Examples 1 and 3 to 6, the same samples as above were irradiated with active energy rays (ultraviolet rays; UV) under the same conditions as in Test Example 1 to remove the adhesive. By curing, a sample after irradiation with active energy rays was obtained. The storage elastic modulus (after UV; MPa) at 23° C. of the obtained sample after irradiation with active energy rays was measured in the same manner as the sample before irradiation with active energy rays. Table 3 shows the results.

[Test Example 3] (Measurement of total light transmittance)
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet produced in each production example was attached to glass, and this was used as a sample for measurement. After performing background measurement on glass, the above measurement sample was measured according to JIS K7361-1: 1997 with a haze meter (manufactured by Nippon Denshoku Industries, product name "SH-7000"). Transmittance (%) was measured. Table 3 shows the results.

Further, the third layer side surface of the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples was laminated to glass, and the total light transmittance (%) was measured in the same manner as described above. The adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3 were irradiated with active energy rays under the same conditions as in Test Example 1 to cure the adhesive. After that, the above measurements were performed. Table 5 shows the results.

[Test Example 4] (Measurement of haze value)
The haze value (%) of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet prepared in each production example was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") according to JIS K7136:2000. bottom. Table 3 shows the results.

Further, the haze value (%) of the pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples was measured in the same manner as described above. The adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3 were irradiated with active energy rays under the same conditions as in Test Example 1 to cure the adhesive. After that, the above measurements were performed. Table 5 shows the results.

[Test Example 5] (Measurement of adhesive strength)
The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheet prepared in each production example, and the exposed pressure-sensitive adhesive layer was covered with a polyethylene terephthalate (PET) film having an easy-adhesion layer (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness : 100 μm) to obtain a laminate of release sheet/adhesive layer/PET film. The laminate thus obtained was cut into a piece having a width of 25 mm and a length of 100 mm, which was used as a sample.

In an environment of 23 ° C. and 50% RH, the heavy release type release sheet was peeled off from the sample, and the exposed adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.). pressure was applied at 0.5 MPa and 50° C. for 20 minutes. Then, after leaving it for 24 hours under the conditions of 23° C. and 50% RH, using a tensile tester (manufactured by Orientec Co., Ltd., product name “Tensilon”), under the conditions of a peel speed of 300 mm / min and a peel angle of 180 degrees. Adhesion (before UV; N/25 mm) was measured. Conditions other than those described here were measured according to JIS Z0237:2009. Table 3 shows the results.

On the other hand, a PET film was laminated on the first layer side surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples, and the third layer side surface was attached to soda lime glass in the same manner as above. Adhesion (before UV; N/25 mm) was measured. Table 5 shows the results.

Further, for the pressure-sensitive adhesive sheets produced in Production Examples 1 and 3 to 6, the pressure-sensitive adhesive layer was applied to soda lime glass in the same manner as described above, autoclaved, and then subjected to 24° C. under conditions of 23° C. and 50% RH. After leaving for a period of time, an active energy ray was irradiated through the PET film under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer. The adhesive strength (after UV; N/25 mm) of the cured adhesive layer was measured in the same manner as described above. Table 3 shows the results.

On the other hand, for the adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3, a PET film was laminated on the surface of the adhesive layer on the first layer side, and the surface on the third layer side was laminated. was applied to soda lime glass, and the adhesive strength after irradiation with active energy rays (after UV; N/25 mm) was measured in the same manner as above. Table 5 shows the results.

[Test Example 6] (Measurement of irregularity 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 × width 50 mm × thickness 0.5 mm), ultraviolet curable ink (manufactured by Teikoku Ink Co., Ltd., product name “POS-911 ink”) ) was screen-printed into a picture frame (outer shape: 90 mm long, 50 mm wide, 5 mm wide). Next, ultraviolet rays are irradiated (80 W/cm ² , 2 metal halide lamps, lamp height 15 cm, belt speed 10 to 15 m/min) to cure the printed UV curable ink, and the height of the step due to printing A stepped glass plate having a thickness of any one of 5 μm, 10 μm, 15 μm, 20 μm and 25 μm was produced.

The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheet prepared in each production example, and the exposed pressure-sensitive adhesive layer was covered with a polyethylene terephthalate (PET) film having an easy-adhesion layer (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 100 μm) of the easy-adhesion layer. Then, the heavy release type release sheet was peeled off to expose the pressure-sensitive adhesive layer. Then, using a laminator (manufactured by Fujipla Co., Ltd., product name "LPD3214"), the laminate was laminated to each stepped glass plate so that the adhesive layer covered the entire surface of the picture frame-shaped print, and this was used as an evaluation sample. bottom.

The resulting sample for evaluation was autoclaved under conditions of 50° C. and 0.5 MPa for 30 minutes, and then allowed to stand at normal pressure, 23° C. and 50% RH for 24 hours. The pressure-sensitive adhesive sheets produced in Production Examples 1 and 3 to 6 were irradiated with active energy rays under the same conditions as in Test Example 1 through the PET film to cure the 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 conformability to irregularities was evaluated. The conformability to irregularities is judged by whether or not the printed unevenness is completely filled with the adhesive layer. If air bubbles, floating, peeling, etc. are observed at the interface between the printed unevenness and the adhesive layer, the printing unevenness is judged. It is judged that the unevenness could not be followed. Here, the irregularity followability was evaluated as the irregularity followability rate (%) represented by the following formula. Table 3 shows the results.
Unevenness follow-up rate (%) = {(height of level difference maintained in buried state without air bubbles, floating, peeling, etc. after endurance test (μm)) / (thickness of adhesive layer)} × 100

[Test Example 7] (Evaluation of blister resistance)
One of the heavy release type release sheets was peeled off from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and the surface of the exposed pressure-sensitive adhesive layer on the third layer side was applied to a plastic plate (Mitsubishi Gas Chemical Co., Ltd. company, product name "Iupilon Sheet MR58U", thickness: 0.7 mm, containing ultraviolet absorber) was attached to the PC board side to obtain a plastic board with an adhesive layer.

The other heavy release type release sheet was peeled off from the plastic plate with the pressure-sensitive adhesive layer obtained above, and the surface of the exposed pressure-sensitive adhesive layer on the first layer side was covered with a soda lime glass plate (Japan) with a size of 70 mm × 150 mm. (manufactured by Sheet Glass Co., Ltd., thickness: 0.7 mm). Then, it was autoclaved for 20 minutes under the conditions of 50° C. and 0.5 MPa, and left at normal pressure, 23° C. and 50% RH for 24 hours.

For the adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3, active energy rays were applied to the adhesive layer through the plastic plate under the same conditions as in Test Example 1. The adhesive layer was cured by irradiation. In this way, a structure (70 mm×150 mm) was obtained in which the plastic plate and the glass plate were laminated together with the adhesive layer.

The above structure was stored for 72 hours under high temperature and high humidity conditions of 85° C. and 85% RH. After curing, the state of the interface between the adhesive layer and the adherend (plastic plate, glass plate) was visually observed, and the blister resistance was evaluated according to the following criteria. Table 5 shows the results.
⊚: There was no air bubble, floating or peeling.
◯: No lifting or peeling, and a few air bubbles were generated, but the level was not a problem.
x: Lifting and peeling occurred.

[Test Example 8] (Measurement of luminous flux transmittance)
As shown in FIG. 5, an adhesive is applied to the center of the upper surface of a soda-lime glass plate (manufactured by Nippon Sheet Glass Co., Ltd., length 70 mm x width 70 mm x thickness 1.1 mm) as a substrate 51, and a convex portion 52 is formed. A polyethylene terephthalate (PET) film (manufactured by Unitika Ltd., product name “Emblet”, length 10 mm×width 10 mm×thickness 12 μm) was attached as an adherend 5 .

One of the heavy release type release sheets was peeled off from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples to expose the third layer side surface of the pressure-sensitive adhesive layer. Then, as shown in FIG. 6, the exposed surface of the pressure-sensitive adhesive layer 11 on the third layer side was attached to the surface of the adherend 5 on which the projections 52 were present. Then, it was autoclaved for 20 minutes under the conditions of 50° C. and 0.5 MPa, and left at normal pressure, 23° C. and 50% RH for 24 hours. Finally, the other heavy release type release sheet was peeled off from the pressure-sensitive adhesive layer 11, and this was used as a sample.

A small-diameter measurement attachment (manufactured by Nippon Denshoku Co., Ltd.) is used for the flat portion of the sample, specifically, a position 15 to 25 mm away from the edge of the convex portion 52, and a light beam of 7 mmφ is transmitted. The luminous flux transmittance (%) of the flat portion was measured according to JIS K7361-1:1997. The luminous flux transmittance of this flat portion was measured at five points, and the average value was taken as the luminous flux transmittance (%) of the flat portion. An example of the luminous flux of the flat portion is indicated by L1 in FIG.

In the same manner as described above, a light beam of 7 mmφ is transmitted through the vicinity of the unevenness of the sample, specifically, a position within 10 mm from the edge of the convex portion 52 (inside the dotted line frame in FIG. 5), The luminous flux transmittance (%) in the vicinity of the unevenness was measured. The luminous flux transmittance in the vicinity of the unevenness was measured at five points, and the average value was taken as the luminous flux transmittance (%) in the vicinity of the unevenness. An example of the luminous flux in the vicinity of the unevenness is indicated by L2 in FIG.

A difference (point) was calculated by subtracting the luminous flux transmittance in the vicinity of the unevenness from the obtained luminous flux transmittance in the flat part. Also, the ratio of the luminous flux transmittance in the vicinity of the unevenness to the obtained luminous flux transmittance in the flat area (luminous flux transmittance in the vicinity of the unevenness/luminous flux transmittance in the flat area) was calculated. Each result is shown in Table 5.

[Test Example 9] (Evaluation of uneven light transmission)
The sample prepared in Test Example 8 was placed with the substrate side down on a tablet terminal (manufactured by Apple Inc., product name “iPad (registered trademark)”, resolution: 264 ppi). Whether or not there is unevenness in light transmission of this sample was visually determined, and the unevenness in light transmission was evaluated according to the following criteria. Table 5 shows the results.
A: There was no unevenness in light transmission.
○: Light transmission was slightly uneven, but at a satisfactory level.
x: There was unevenness in light transmission.

[Test Example 10] (Evaluation of hiding property)
The adhesive sheets obtained in Examples and Comparative Examples were cut into a length of 70 mm x width of 70 mm, and the adhesive layer of the adhesive sheet was applied to two soda lime glass plates (manufactured by Nippon Sheet Glass Co., Ltd., length of 70 mm x width of 70 mm x thickness). 1.1 mm). The adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3 were irradiated with an active energy ray through one of the soda lime glass plates under the same conditions as in Test Example 1. The adhesive layer was cured. These were used as samples in this test example.

As backgrounds, black background 1 (L*: 29.8, a*: -0.7, b*: 0.6) and black background 2 (L*: 39.2, a*: -0.4) , b*: 0.4) were each printed on paper. Then, the black background 2 was shifted and superimposed on the black background 1 to form a boundary portion between the black background 1 and the black background 2 .

The sample was placed over a background containing the border. Then, at a position 50 cm from the sample, whether or not the boundary is hidden (the boundary is difficult to see and there is a sense of unity) is examined under a three-wavelength fluorescent lamp (distance from the fluorescent lamp: 200 cm). , and visually judged, and the hiding property was evaluated according to the following criteria. Table 5 shows the results.
⊚: The boundary portion was sufficiently hidden.
◯: The boundary portion was hidden to some extent.
x: The boundary was not clearly hidden.

The color of the black backgrounds 1 and 2 (L*a*b* defined by the CIE 1976 L*a*b* color system) is determined by a spectrophotometer (manufactured by BYK, product name: Spectro-Guide ”).

[Test Example 11] (Evaluation of visibility)
On a display with a size of 15.6 inches and a resolution of 1366 x 768 (manufactured by Fujitsu Ltd., product name “LITEBOOK A574/H”), white background, black characters (font: MS P Gothic) are displayed in a size of 5 to 20 points. 100% is displayed in increments of 1 point.

A sample prepared in the same manner as in Test Example 10 was placed on the display. Then, at a position of 50 cm from the display, the size of characters that can be visually recognized was confirmed, and the visibility was evaluated according to the following criteria. Table 3 shows the results.
(double-circle): The character of 6 points was visually recognized.
○: 6-point characters were not completely visible, but 8-point characters were visible.
Δ: 8-point characters were not completely visible, but 15-point characters were visible.
x: 15-point characters were not visible.

As can be seen from Table 5, the pressure-sensitive adhesive sheets obtained in Examples had suppressed unevenness in transmittance, and were excellent in concealability and visibility. In addition, as can be seen from Tables 3 and 5, the pressure-sensitive adhesive sheets obtained in Examples were excellent in conformability to irregularities and resistance to blistering.

The pressure-sensitive adhesive sheet of the present invention can be suitably used, for example, for laminating a display body constituent member having unevenness and a desired display body constituent member in a display body having a black frame material.

DESCRIPTION OF SYMBOLS 1, 1A... Adhesive sheet 11... Adhesive layer 111... Colored adhesive layer 112... Colorless adhesive layer 12a, 12b... Release sheet 2A, 2B... Display body 21... First display body constituent member 22... Second display Body constituent member 23 Print layer 30 Backlight 31 Substrate 32 Luminescent body 41 Diffusion member 42 Liquid crystal panel 5 Adherend 51 Substrate 52 Convex portion L1 Luminous flux at flat portion L2 Near uneven portion luminous flux

Claims (3)

one display body constituent member;
other display body constituent members;
A display body comprising an adhesive layer for adhering the one display body constituent member and the other display body constituent member to each other,
At least one of the one display body constituting member and the other display body constituting member has unevenness on a surface thereof to be bonded by the pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer comprises at least one colored pressure-sensitive adhesive layer,
The ratio of the luminous flux transmittance in a portion within 10 mm in the planar direction from the position where there is a step due to the unevenness to the luminous flux transmittance in a flat portion sufficiently distant in the planar direction from the unevenness to the extent that it is not affected by the unevenness is 0 .980 or more,
A display, wherein the pressure-sensitive adhesive constituting the colored pressure-sensitive adhesive layer contains 0.0073 % by mass or more of a colorant. 2. The display according to claim 1, wherein the unevenness is caused by a printed layer provided on a part of the display in plan view. 3. The display according to claim 1, wherein the unevenness is caused by a plurality of light emitters provided on the substrate.

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