TWI834851B - Adhesive sheets and displays - Google Patents

Abstract

[Problem] Provide an adhesive sheet and display that can suppress uneven transmittance of the adhesive layer. [Solution] An adhesive sheet 1 having an adhesive layer 11 attached to an adherend having an uneven surface, and the adhesive layer 11 is at least one colored adhesive layer 111 and at least one layer The colorless adhesive layer 112 is a laminated body, and the colorless adhesive layer 112 is located on the uneven surface of the adherend that contacts the adhesive layer 11 .

Description

Adhesive sheets and displays

The present invention relates to an adhesive sheet attached to an adherend having an uneven surface and a display using the adhesive sheet.

Displays (displays) in recent years include automotive displays such as automotive panels, car navigation systems, various counters installed on dashboards, displays such as tablet terminals for general users, and tablet terminals for commercial use. Or displays such as digital signage, displays such as digital signage for outdoor use, etc., increasingly use image display devices such as liquid crystal display devices or organic light-emitting diode devices.

In the above-mentioned displays, including those for automobiles, there is a demand for creating a sense of integration with peripheral components of the display such as components and improving design when the lamp of the display is turned off. The display is colored for this purpose. Patent Document 1 as an example discloses an invention in which a colored layer containing a colored pigment dispersed in an adhesive is provided on a part of a layer constituting a display. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2012-234028

[Problem to be solved by the invention]

In the invention described in Patent Document 1, the colored layer is provided so as to connect a frame-shaped concealing layer formed on the viewing plane of the display body with a level difference. However, in the display body configured in this way, transmittance is uneven in the colored layer, so there is a problem that bright spots occur in the display body.

The present invention was developed in view of the above-mentioned actual situation, and aims to provide an adhesive sheet and a display that can suppress uneven transmittance in the adhesive layer. [A means to solve problems]

In order to achieve the above object, first, the present invention provides an adhesive sheet, which is an adhesive sheet having an adhesive layer attached to an adherend having an uneven surface, and is characterized in that the adhesive layer is at least one layer of coloring. A laminate of an adhesive layer and at least one colorless adhesive layer located on the uneven surface of the adherend in contact with the adhesive layer (Invention 1).

In the above invention (Invention 1), when the adhesive layer contacts and follows the unevenness of the adherend, the layer that contacts the unevenness of the adherend is not a colored adhesive layer but a colorless adhesive layer. The unevenness of the adherend can be absorbed to some extent by the colorless adhesive layer. Therefore, compression or deformation of the colored adhesive layer due to unevenness of the adherend is suppressed, and therefore uneven transmittance of the adhesive layer can be suppressed.

In the above invention (Invention 1), it is preferable that the thickness of the colorless adhesive layer located on the surface contacting the uneven surface of the adherend is greater than the depth or height of the uneven surface of the adherend (Invention 2).

In the above-mentioned inventions (Inventions 1 and 2), it is preferable that the adhesive layer is an adhesive layer for bonding one display component and another display component (Invention 3).

In the above invention (Inventions 1 to 3), it is preferable that the storage modulus of the adhesive constituting the colorless adhesive layer at 23°C is 0.01 MPa or more and 1 MPa or less (Invention 4).

In the above invention (Inventions 1 to 4), it is preferable that the storage modulus at 23°C of the adhesive constituting the colored adhesive layer is 0.01 MPa or more and 1 MPa or less (Invention 5).

In the above invention (Inventions 1 to 5), it is preferable that the adhesive layer is in contact with the release surfaces of the two release sheets and sandwiched between the release sheets (Invention 6).

Secondly, the present invention provides a display which has one display component, other display component, and an adhesive layer for bonding the one display component and the other display component to each other. The display is characterized in that at least one of the above-mentioned one display component and the above-mentioned other display component has an uneven surface on a side bonded via the above-mentioned adhesive layer, and the above-mentioned adhesive layer is the above-mentioned adhesive sheet. (Invention 1-6) Adhesive layer (Invention 7).

Thirdly, the present invention provides a display which has one display component, other display component, and an adhesive layer for bonding the one display component and the other display component to each other. The display is characterized in that at least one of the above-mentioned one display component and the above-mentioned other display component has an uneven surface on a side bonded via the above-mentioned adhesive layer, and the above-mentioned adhesive layer has at least one layer The ratio of the light beam transmittance of the colored adhesive layer in the vicinity of the above-mentioned uneven areas to the light beam transmittance of the flat areas is 0.980 or more (Invention 8).

In the above inventions (Inventions 7 and 8), the unevenness may be unevenness caused by a printing layer provided on a part of the viewing plane of the display (Invention 9).

In the above-mentioned inventions (Inventions 7 and 8), the unevenness may be caused by a plurality of light emitters provided on the substrate (Invention 10). [Effects of the invention]

According to the adhesive sheet and display body of the present invention, uneven transmittance in the adhesive layer can be suppressed.

[Form for carrying out the invention]

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

Here, as is known, when the colored adhesive layer contacts and follows the unevenness of the adherend, the colored adhesive layer may be compressed or deformed due to the unevenness of the adherend. Therefore, the color of the colored adhesive layer may vary, resulting in uneven transmittance. For example, in the compressed portion of the colored adhesive layer, the color becomes thicker and the transmittance decreases. In contrast, since the adhesive sheet of this embodiment has the above-mentioned structure, the layer that contacts the unevenness of the adherend is not a colored adhesive layer but a colorless adhesive layer. Therefore, compression or deformation of the colored adhesive layer due to unevenness of the adherend is suppressed. Therefore, uneven transmittance in the adhesive layer can be suppressed.

In the adhesive sheet of this embodiment, it is preferable that the thickness of the colorless adhesive layer located on the surface contacting the uneven surface of the adherend is greater than the depth or height of the uneven surface of the adherend. Therefore, the unevenness of the adherend can be absorbed by the colorless adhesive layer, which more effectively prevents the colored adhesive layer from being compressed or deformed due to the unevenness. Therefore, uneven transmittance in the adhesive layer is more effectively suppressed.

The above-mentioned adhesive layer is preferably an adhesive layer used to bond one display component and other display component. The display body and display body components will be described later. In a display obtained by using the adhesive layer of the adhesive sheet of this embodiment, by suppressing uneven transmittance of the adhesive layer, the occurrence of bright spots on the display can be suppressed. However, the use of the adhesive sheet of this embodiment is not limited to a display body.

The specific structure of an example of the adhesive sheet of this embodiment is shown in FIG. 1 . As shown in FIG. 1 , the adhesive sheet 1 is composed of two peeling sheets 12a and 12b and is in contact with the peeling surfaces of the two peeling sheets 12a and 12b and is sandwiched between the two peeling sheets 12a and 12b. composed of adhesive layer 11. In addition, the peeling surface of the peeling sheet in this specification refers to the surface of the peeling sheet that has peelability, and includes both the surface that has been peeled off and the surface that has not been peeled but shows peelability.

The adhesive layer 11 of this embodiment is a laminate of one colored adhesive layer 111 and one colorless adhesive layer 112 . However, the present invention is not limited thereto. The colored adhesive layer 111 and the colorless adhesive layer 112 may each have multiple layers. The colorless adhesive layer 112 is located on the uneven surface of the adherend that contacts the adhesive layer 11 .

1. Each component 1-1. Adhesive layer The colored adhesive layer 111 is preferably composed of an adhesive containing a colorant. On the other hand, the colorless adhesive layer 112 is preferably made of an adhesive that does not contain a colorant, and is preferably colorless and transparent. "Containing no coloring agent" means "substantially not containing coloring agent", and includes not only not containing coloring agent at all, but also including the case of containing an amount of coloring agent that does not impair the effects of this embodiment. The amount is preferably 0.1% by mass or less, particularly preferably 0.01% by mass or less, more preferably 0.001% by mass or less, and most preferably 0% by mass.

The types of adhesives constituting the colored adhesive layer 111 and the colorless adhesive layer 112 of the adhesive sheet 1 of this embodiment are not particularly limited, such as acrylic adhesives, polyester adhesives, polyurethane adhesives, and rubber adhesives. , silicone adhesives, etc. can be used. In addition, the adhesive may be any one of emulsion type, solvent type, or solvent-free type, and may be any one of cross-linked type or non-cross-linked type. Among these, acrylic adhesives are preferred because of their excellent adhesive properties and optical properties.

The acrylic adhesive may be active energy ray hardening or active energy ray non-hardening. The acrylic adhesive is preferably a cross-linking type, and a thermal cross-linking type is even better.

The adhesive constituting the colored adhesive layer 111 and the adhesive constituting the colorless adhesive layer 112 may be of the same type or different types. For example, one may be an active energy ray-hardening acrylic adhesive, and the other may be an active energy ray-non-hardening acrylic adhesive. Even if both are active energy ray-curable acrylic adhesives or active energy ray-non-curable acrylic adhesives, the composition of the adhesive or the monomer composition of the main polymer may be different.

The adhesive constituting the colored adhesive layer 111 and the adhesive constituting the colorless adhesive layer 112 are specifically an adhesive composition (hereinafter) containing a (meth)acrylate polymer (A) and a cross-linking agent (B). In some cases, it is called "adhesive composition P") and is preferably cross-linked. In the case of the colored adhesive layer 111, it is preferable that the adhesive composition P further contains a coloring agent (C). When the above-mentioned adhesive is an active energy ray-curable adhesive, it is preferable that the adhesive composition P further contains an active energy ray-curable component (D).

The adhesive agent obtained from such adhesive composition P can exhibit excellent optical properties, adhesive force, durability (concave-convex following properties under high temperature and high humidity conditions, blistering resistance (blister resistance)), etc. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. Other similar terms are the same. In addition, "polymer" also includes the concept of "copolymer".

(1) Ingredients of adhesive composition (1-1) (Meth)acrylate polymer (A) The (meth)acrylate polymer (A) of this embodiment uses a reactive group-containing monomer containing a reactive group that reacts with the cross-linking agent (B) in the molecule as the monomer unit constituting the polymer. Better. The reactive group derived from the monomer containing the reactive group reacts with the cross-linking agent (B) to form a cross-linked structure (three-dimensional network structure), thereby obtaining an adhesive with the desired cohesive force.

Preferable examples of the above-mentioned reactive group-containing monomer include monomers having a hydroxyl group in the molecule (hydroxyl-containing monomer), monomers having a carboxyl group in the molecule (carboxyl-containing monomer), and monomers having an amine group in the molecule (hydroxyl-containing monomer). Amine monomer), etc. Among these, a hydroxyl group-containing monomer or a carboxyl group-containing monomer having excellent reactivity with the cross-linking agent (B) is preferred, and a hydroxyl group-containing monomer and a carboxyl group-containing monomer may be used in combination.

Hydroxyl-containing monomers, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate , 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxyalkyl (meth)acrylate, etc. Among them, from the viewpoint of the reactivity of the hydroxyl group in the obtained (meth)acrylate polymer (A) with the cross-linking agent (B) and the copolymerizability with other monomers, a hydroxyalkane having a carbon number of 1 to 4 The preferred base is hydroxyalkyl (meth)acrylate. Specific examples include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like, and particularly 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate. These can be used individually or in combination of 2 or more types.

Carboxyl group-containing monomers, such as ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Among them, acrylic acid is preferred from the viewpoint of the reactivity between the carboxyl group in the obtained (meth)acrylate polymer (A) and the cross-linking agent (B) and the copolymerizability with other monomers. These can be used individually or in combination of 2 or more types.

Amino group-containing monomers, such as aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. These can be used individually or in combination of 2 or more types. In addition, this amine group-containing monomer does not include a nitrogen atom-containing monomer described below.

The (meth)acrylate polymer (A) preferably contains a reactive group-containing monomer as a monomer unit constituting the polymer. The lower limit is preferably 5 mass% or more, and particularly preferably 10 mass% or more. , and preferably contains more than 15% by mass. Furthermore, the (meth)acrylate polymer (A) contains a reactive group-containing monomer as a monomer unit constituting the polymer. The upper limit is preferably 35 mass% or less, and particularly 30 mass% or less. Preferably, the content is preferably 25% by mass or less. When the (meth)acrylate polymer (A) contains a reactive group-containing monomer as a monomer unit in the above-mentioned amount, a good cross-linked structure is formed in the obtained adhesive, and the desired cohesive force is obtained. . Moreover, when a coloring agent (C) is contained, the dispersibility of the coloring agent (C) in the obtained adhesive tends to become favorable. Therefore, the obtained adhesive exhibits appropriate cohesive force, has excellent reproducibility and uniformity of optical properties, and can easily control the beam transmittance described below to a desired value. Furthermore, when the reactive group-containing monomer is a hydroxyl-containing monomer, the content is preferably 10 mass% or more, and particularly preferably 15 mass% or more. In this case, a predetermined amount of hydroxyl groups remains in the adhesive. The hydroxyl group is a hydrophilic group. When such a hydrophilic group is present in an adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, the compatibility with the water immersed in the adhesive under such high temperature and high humidity conditions will It is good. As a result, the adhesive is suppressed from whitening when it returns to normal temperature and humidity (excellent whitening resistance against heat and humidity).

In addition, the (meth)acrylate polymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. Since the carboxyl group is an acid component, by not containing carboxyl group-containing monomers, problems caused by acid can be suppressed on the objects to which the adhesive is attached, such as transparent conductive films or metal films doped with tin-doped indium oxide (ITO). situation, can suppress such problems (corrosion, change in resistance value, etc.) caused by acid. However, it is allowed to contain a predetermined amount of the carboxyl group-containing monomer to the extent that such a problem does not occur. Specifically, the amount of carboxyl group-containing monomer containing monomer units in the (meth)acrylate polymer (A) is allowed to be 0.1 mass% or less, preferably 0.01 mass% or less, and more preferably 0.001 mass% or less.

The (meth)acrylate polymer (A) preferably contains an alkyl (meth)acrylate as a monomer unit constituting the polymer. Therefore, good adhesion can be exhibited. The alkyl group may be a linear chain or a branched chain.

From the viewpoint of adhesiveness, the alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having an alkyl group having 1 to 20 carbon atoms. Alkyl (meth)acrylate with an alkyl group having 1 to 20 carbon atoms, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate Ester, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-(meth)acrylate Decyl ester, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, etc. Among them, from the viewpoint of further improving the adhesiveness, alkyl (meth)acrylate having an alkyl group having 1 to 8 carbon atoms is preferred, and methyl (meth)acrylate, n-butyl (meth)acrylate, or 2-ethylhexyl (meth)acrylate is particularly preferred, and methyl methacrylate, n-butyl acrylate, or 2-ethylhexyl acrylate is more preferred. These can be used individually or in combination of 2 or more types.

The (meth)acrylate polymer (A) contains an alkyl (meth)acrylate as a monomer unit constituting the polymer, preferably at least 45% by mass, particularly preferably at least 55% by mass, and more preferably at least 65% by mass. good. When the lower limit of the alkyl (meth)acrylate content is the above, the (meth)acrylate polymer (A) can exhibit appropriate adhesiveness. In addition, when the colorant (C) is contained, the dispersibility of the colorant (C) in the adhesive tends to be good, and the loss of desired adhesiveness of the (meth)acrylate polymer (A) can be suppressed. Therefore, the obtained adhesive exhibits appropriate adhesiveness, has excellent reproducibility and uniformity of optical properties, and can easily control the beam transmittance described below to a desired value. On the other hand, the (meth)acrylate polymer (A) contains an alkyl (meth)acrylate as a monomer unit constituting the polymer, preferably 99% by mass or less, more preferably 95% by mass or less, and 90% by mass or less. A content of less than 85% by mass is particularly preferred, and a content of less than 85% by mass is more preferred. When the upper limit of the alkyl (meth)acrylate content is the above, an appropriate amount of other monomer components such as a reactive functional group-containing monomer can be introduced into the (meth)acrylate polymer (A).

The (meth)acrylate polymer (A) may contain a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) as a monomer unit constituting the polymer. Since the alicyclic structure-containing monomer has a large volume, it is speculated that its presence in the polymer increases the distance between the polymers, thereby making the obtained adhesive excellent in flexibility. Therefore, the adhesive has excellent unevenness following properties.

The carbocyclic ring of the alicyclic structure in the alicyclic structure-containing monomer may have a saturated structure or may have a partially 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 providing an appropriate distance between the obtained (meth)acrylate polymers (A) and providing high stress relaxation properties due to the adhesive, the alicyclic structure (polycyclic structure) in which the above-mentioned alicyclic structure is polycyclic is: good. Furthermore, considering the compatibility between the (meth)acrylate polymer (A) and other components, the above-mentioned polycyclic structure is particularly preferred with two to four rings. In addition, from the same viewpoint as above for providing stress relaxation properties, the number of carbon atoms in the alicyclic structure (that is, the total number of carbon atoms in the part forming the ring, or the total number of carbon atoms in the case where multiple rings exist independently) is usually A score of 5 or above is better, and a score of 7 or above is particularly good. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited. From the same viewpoint of compatibility as described above, 15 or less is preferred, and 10 or less is particularly preferred.

Specific examples of the above-mentioned alicyclic structural monomers include cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, isocamphenyl (meth)acrylate, (meth)acrylate ) dicyclopentenyl acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. Among them, dicyclopentyl (meth)acrylate (number of carbon atoms in the alicyclic structure) exhibits better unevenness following properties. : 10), (meth)adamantyl acrylate (number of carbon atoms in the alicyclic structure: 10), or isocamphenyl (meth)acrylate (number of carbon atoms in the alicyclic structure: 7), especially (methyl) ) isocamphenyl acrylate is preferred, and isocamphenyl acrylate is even more preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

When the (meth)acrylate polymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, the alicyclic structure-containing monomer is preferably contained in an amount of 1 mass % or more, and preferably 4 mass % or more. Especially good, 8 mass% or more is more preferable. Furthermore, the (meth)acrylate polymer (A) preferably contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer at 30% by mass or less, particularly preferably at most 20% by mass, and more preferably at most 10% by mass. . When the content of the monomer containing an alicyclic structure is within the above range, the adhesive obtained has better unevenness following properties.

The (meth)acrylate polymer (A) may contain a nitrogen atom-containing monomer as a monomer unit constituting the polymer. Monomers containing nitrogen atoms are present in the polymer as structural units, which can provide the adhesive with a predetermined polarity, and can also provide excellent affinity for adherends with a certain degree of polarity, such as glass. From the viewpoint that the (meth)acrylate polymer (A) has moderate rigidity, the nitrogen atom-containing monomer is preferably a monomer having a nitrogen-containing heterocyclic ring. Furthermore, from the viewpoint of increasing the degree of freedom of the portion derived from the nitrogen atom-containing monomer in the high-level structure of the constituted adhesive, the nitrogen atom-containing monomer is preferably used to form the (meth)acrylate polymer. The polymerization of (A) does not contain a reactive unsaturated double bond group other than one polymerizable group.

Nitrogen-containing heterocyclic monomers such as N-(meth)acrylylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acrylylpyrrolidone, N-(meth)propylene Cylpiperidine, N-(meth)acrylylpyrrolidine, N-(meth)acrylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4 -Vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthaloimide, etc. Among them, N-(methyl) exhibits better adhesion. Acrylyl morpholine is preferred, and N-acrylyl morpholine is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

When the (meth)acrylate polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the nitrogen atom-containing monomer is preferably contained in an amount of 1% by mass or more, and particularly preferably in an amount of 2% by mass or more. , more than 4% by mass is better. Furthermore, the (meth)acrylate polymer (A) preferably contains 24 mass % or less of a nitrogen atom-containing monomer as a monomer unit constituting the polymer, particularly preferably 16 mass % or less, and more preferably 8 mass % or less. When the content of nitrogen atom-containing monomers is within the above range, the obtained adhesive can fully exert its excellent adhesion to glass.

The (meth)acrylate polymer (A) may optionally contain other monomers as monomer units constituting the polymer. In order not to impair the aforementioned effects of the reactive functional group-containing monomer, other monomers are preferably monomers that do not contain reactive functional groups. Examples of such monomers include alkoxyalkyl (meth)acrylate such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, vinyl acetate, styrene, and the like. These can be used individually or in combination of 2 or more types.

The (meth)acrylate polymer (A) is preferably a linear polymer. Since it is a linear polymer, the entanglement of molecular chains can easily occur, and it is expected that the cohesion force will be improved. Therefore, it is easy to obtain an adhesive with excellent unevenness following properties and blister resistance under high temperature and high humidity conditions.

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 it is expected that the cohesive force will be improved. Therefore, it is easy to obtain an adhesive with excellent unevenness following properties or foaming resistance under high temperature and high humidity conditions.

The polymerization state of the (meth)acrylate polymer (A) may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, and particularly preferably 400,000 or more. From the viewpoint of the dispersibility of the colorant (C), More than 500,000 is better. When the lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is the above, the obtained adhesive will tend to have appropriate values such as gel fraction and storage modulus, and will be suitable for use under high temperature and high humidity. Those with better unevenness following the conditions or blistering resistance. In addition, the dispersibility of the colorant (C) in the adhesive tends to be improved. Therefore, the obtained adhesive has excellent reproducibility and uniformity of optical physical properties, and it is easy to control the beam transmittance described below to a desired value. numerical value.

The upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 1.5 million or less, more preferably 1.2 million or less, particularly preferably 1 million or less, and more preferably 800,000 or less. When the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is the above, numerical values such as the gel fraction and storage modulus of the adhesive obtained are likely to be appropriate, and the initial unevenness following properties can be easily achieved. Become better. The weight average molecular weight in this specification is a standard polystyrene-converted value measured by gel permeation chromatography (GPC).

Moreover, in the adhesive composition P, the (meth)acrylate polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more types.

(1-2) Cross-linking agent (B) The cross-linking agent (B) cross-links the (meth)acrylate polymer (A) by heating the adhesive composition P, thereby forming a three-dimensional network structure. Therefore, the cohesive force of the obtained adhesive is improved, and it is excellent in unevenness following and blistering resistance under high-temperature and high-humidity conditions.

The above-mentioned cross-linking agent (B) is preferably one that reacts with the reactive group possessed by the (meth)acrylate polymer (A), such as isocyanate cross-linking agent, epoxy cross-linking agent, amine cross-linking agent, Melamine cross-linking agents, aziridine cross-linking agents, hydrazine cross-linking agents, aldehyde cross-linking agents, tetrazoline cross-linking agents, metal alkoxide cross-linking agents, metal chelating agent cross-linking agents agents, metal salt cross-linking agents, ammonium salt cross-linking agents, etc. Among the above, when the reactive group of the (meth)acrylate polymer (A) is a hydroxyl group, it is preferable to use an isocyanate-based crosslinking agent that has excellent reactivity with the hydroxyl group. When the reactive group of the polymer (A) is a carboxyl group, it is preferable to use an epoxy cross-linking agent that has excellent reactivity with the carboxyl group. In addition, when the reactive groups of the (meth)acrylate polymer (A) are hydroxyl groups and carboxyl groups, an isocyanate cross-linking agent and an epoxy cross-linking agent may be used together, or only the (meth)acrylate cross-linking agent may be used. group) acrylate polymer (A) has a large content of reactive groups, which is a preferred cross-linking agent. The cross-linking agent (B) may be used singly or in combination of two or more types.

The isocyanate cross-linking agent contains at least a polyisocyanate compound. Polyisocyanate compounds include, for example, toluene diisocyanate, diphenylmethane diisocyanate, aromatic polyisocyanates such as xylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenyl Alicyclic polyisocyanates such as methylmethane diisocyanate, and their biurets and isocyanurates, and further combined with ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil The adducts of reactants of small molecules containing active hydrogen compounds, etc. Among them, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates, especially trimethylolpropane-modified toluene diisocyanate and trimethylolpropane-modified xylene diisocyanate, are used. good.

Epoxy cross-linking agents such as 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N',-tetraepoxypropyl-m -Xylylenediamine, ethylene glycol dialpoxypropyl ether, 1,6-hexanediol dialpoxypropyl ether, trimethylolpropane dialpoxypropyl ether, diepoxypropylaniline, Glycidylamine, etc. Among them, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane is preferred from the viewpoint of reactivity with carboxyl groups.

In the adhesive composition P, the content of the cross-linking agent (B) is preferably 0.01 parts by mass or more, particularly preferably 0.05 parts by mass or more, based on 100 parts by mass of the (meth)acrylate polymer (A). Quality parts or more are better. Moreover, 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, more preferably 0.4 parts by mass or less, and most preferably 0.2 parts by mass or less. When the content of the cross-linking agent (B) is within the above range, the gel fraction, storage modulus, adhesive force, etc. of the adhesive obtained are likely to be suitable, as well as the unevenness following and blistering resistance under high temperature and high humidity conditions. Become a better person.

(1-3) Colorant (C) The colorant (C) may be a pigment or a dye. Pigments can be inorganic pigments or organic pigments. From the viewpoint of the durability of the adhesive obtained, inorganic pigments are preferred. The color of the colorant can be appropriately selected depending on the purpose. For example, if you want to achieve a sense of integration with peripheral components, you can choose according to the color of the peripheral components. Generally, dark or rich colors such as black, brown, dark blue, purple, blue, etc. are better, especially black. good.

Inorganic pigments such as carbon black pigments, cobalt pigments, iron pigments, chromium pigments, titanium pigments, vanadium pigments, zirconium pigments, molybdenum pigments, ruthenium pigments, platinum pigments, ITO (indium tin oxide ) pigments, ATO (antimony tin oxide) pigments, etc.

In addition, organic pigments and organic dyes include, for example, aminium pigments, cyanine pigments, merocyanine pigments, croconium pigments, and squaraine pigments. Squarylium pigments, azlenium pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, phthalocyanine pigments, naphthalocyanine (naphthalocyanine) pigments, naphtholactam pigments, azo pigments, condensed azo pigments, indigo pigments, perinone pigments, perylene Pigments, dioxazine pigments, quinacridone pigments, isoindolinone pigments, quinophthalone pigments, pyrrole pigments, sulfur Indigo (thioindigo) pigments, metal complex pigments (metal complex salt dyes), dithiol metal complex pigments, indophenol (indophenol) pigments, triarylmethane pigments, anthraquinone ) pigments, dioxazine pigments, naphthol pigments, azomethine pigments, benzimidazolone pigments, pyranthrone pigments and Threne pigments, etc.

Black pigments include carbon black, copper oxide, ferric oxide, manganese dioxide, aniline black, activated carbon, etc. In addition, black dyes include high-concentration plant dyes or azo dyes.

The above-mentioned pigments or dyes may be mixed appropriately depending on the purpose.

Among the above colorants, carbon black pigments, nigrosin black dyes and chromate black dyes are preferred from the viewpoint of easily creating a sense of integration with peripheral components. In addition, the surface of the carbon black may be subjected to a predetermined treatment (for example, solvophilicity treatment), or may not be treated.

The above-mentioned colorant has an average haze of a liquid that is diluted 10,000 times with ethyl acetate and has a haze value at a wavelength of 780 nm and a haze value at a wavelength of 380 nm. The lower limit is 1% or more. The one with more than 2% is particularly good, and the one with more than 3% is even better. The upper limit of the average haze of the colorant is preferably 60% or less, more preferably 40% or less, particularly preferably 30% or less, more preferably 20% or less, and most preferably 10% or less. By using an appropriate amount of such a colorant, the obtained colored adhesive layer 111 has suitable optical physical properties. Therefore, the obtained adhesive layer 11 can easily have suitable optical physical properties.

For the above-mentioned colorant, the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm of a liquid diluted 10,000 times with ethyl acetate is preferably 30 points or less, and 25 or less. Better, below 20 points is particularly good, below 16 points is even better, and below 10 points is the best. By using an appropriate amount of such a colorant, the obtained colored adhesive layer 111 has suitable optical physical properties. Therefore, the obtained adhesive layer 11 can easily have suitable optical physical properties.

In addition, the lower limit of the difference in haze value may be 0 points, but from the viewpoint of easily adjusting the aforementioned colored adhesive layer 111 to have suitable optical properties, it is preferably 0.1 points or more, and more preferably 0.5 points or more. A score of 1 or more points is particularly good, and a score of 3 or more points is even better.

The above-mentioned colorant is diluted 10,000 times with ethyl acetate. The haze value at a wavelength of 780nm is preferably 0.1 to 50%, preferably 0.5 to 40%, particularly preferably 1 to 30%, and even more preferably 1.5 to 20%. 2~10% is optimal. In addition, the haze value of the above-mentioned colorant diluted 10,000 times with ethyl acetate at a wavelength of 380 nm is preferably 1 to 60%, preferably 3 to 50%, particularly preferably 6 to 40%, and more preferably 8 to 30%. Good, 10-20% is the best. Therefore, it is easy to satisfy the above-described difference in haze value.

Furthermore, the standard deviation of the haze value of the liquid of the coloring agent diluted 10,000 times with ethyl acetate at each wavelength of 5 nm intervals in the wavelength range of 380 to 780 nm (i.e., 380 nm, 385 nm, 390 nm, ..., 775 nm, 780 nm) is preferably 10 or less, 8 or less is more preferred, 5 or less is particularly preferred, and 2 or less is more preferred. The lower limit of the standard deviation is 0, but is usually preferably 0.1 or more, 0.5 or more is particularly preferred, and 1 or more is more preferred. Therefore, the obtained colored adhesive layer 111 becomes one with suitable optical properties, and therefore, the obtained adhesive layer 11 is easy to become one with suitable optical properties.

From the viewpoint of easily controlling the total light transmittance to a desired value and easily exhibiting excellent hiding properties when the display is turned off, the content of the colorant (C) in the colored adhesive layer 111 is smaller than that of (meth)acrylic acid. 100 parts by mass of the ester polymer (A) is preferably at least 0.01 parts by mass, more preferably at least 0.05 parts by mass, particularly preferably at least 0.1 parts by mass, more preferably at least 0.3 parts by mass, and more preferably at least 0.4 parts by mass. In addition, from the viewpoint of easily controlling the haze value to a desired value and easily exhibiting excellent visibility (easiness of viewing the screen and image) when the display light is on, the above-mentioned content is preferably 8 parts by mass or less, and 4 parts by mass The following is preferred, 2 parts by mass or less is particularly preferred, and 1 part by mass or less is more preferred. Since the content of the colorant (C) is within the above range, the durability of the adhesive obtained will not be reduced, and the adhesive can be fully colored to achieve desired concealment and visibility. "Concealability" in this specification means that when the display body is turned off, the appearance of the display part of the display body and peripheral components such as a frame-shaped printed layer or frame material are harmonious, and the boundaries between these are difficult to see.

(1-4) Active energy ray hardening ingredient (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 preferably contains an active energy ray-curable component (D). In the active energy ray-curable adhesive agent obtained by cross-linking the adhesive composition P, the active energy ray-curable components (D) are polymerized with each other, and it is presumed that the polymerized active energy ray-curable components (D) are entangled in Cross-linked structure (three-dimensional network structure) of (meth)acrylate polymer (A). The adhesive with such a high-level structure exhibits very excellent durability, and is particularly excellent in unevenness following and blistering resistance under high temperature and high humidity conditions.

The active energy ray curable component (D) is not particularly limited as long as it is cured by active energy ray irradiation and can obtain the above effects. It may be a monomer, oligomer, or polymer, or a combination of these. mixture. Among them, for example, polyfunctional acrylate-based monomers with better foaming resistance can be used.

Multifunctional acrylate monomers such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate Ester, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxytrimethylacetate neopentyl glycol di(meth)acrylate, dicyclopentyl Di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, caprolactone modified dicyclopentenyl di(meth)acrylate, ethylene oxide modified di(meth)acrylate ) Acrylate, di(acryloxyethyl) isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate , 2-functional types such as 9,9-bis[4-(2-acryloxyethoxy)phenyl]fluorene; trimethylolpropane tri(meth)acrylate, dipenterythritol Tri(meth)acrylate, propionic acid-modified dineopenterythritol tri(meth)acrylate, neopentylerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate base) acrylate, tris(acrylooxyethyl)isocyanurate, ε-caprolactone modified tris-(2-(meth)acrylooxyethyl)isocyanurate, etc. 3-functional type; 4-functional type such as diglycerol tetra(meth)acrylate, neopentylerythritol tetra(meth)acrylate, etc.; propionic acid-modified dipenterythritol penta(meth)acrylate, etc. The 5-functional type; the 6-functional type of dipenterythritol hexa(meth)acrylate, caprolactone modified dipenterythritol hexa(meth)acrylate, etc. These may be used individually by 1 type, and may be used in combination of 2 or more types. Furthermore, from the viewpoint of compatibility with the (meth)acrylate polymer (A), the polyfunctional acrylate monomer preferably has a molecular weight of less than 1,000.

Among the above, from the viewpoint of the foaming resistance of the adhesive obtained, di(acrylooxyethyl) isocyanurate, tris(acrylooxyethyl) isocyanurate, and ε- Caprolactone-modified tri-(2-(meth)acrylooxyethyl)isocyanurate and other polyfunctional acrylate monomers containing an isocyanurate structure in the molecule, or tricyclic Polyfunctional acrylate monomers such as decane dimethanol (meth)acrylate, which contain a cyclic structure (especially a cycloalkane structure) in the molecule, are preferred, with three or more functional groups and containing isocyanuride in the molecule A multifunctional acrylate monomer with an acid ester structure, or a multifunctional acrylate monomer with more than two functional groups and containing a polycyclic structure (especially a polycyclic structure of a cycloalkane structure) in the molecule is preferred. ε-Caprolactone modified tri-(2-(meth)acrylooxyethyl)isocyanurate or tricyclodecane dimethanol (meth)acrylate are particularly preferred, with ε-hexyl Lactone-modified tri-(2-acryloyloxyethyl) isocyanurate or tricyclodecane dimethanol acrylate is more preferred, and ε-caprolactone-modified tri-(2-acrylic acid) Oxyethyl) isocyanurate is the best.

In the adhesive composition P, the content of the active energy ray curable component (D) is determined based on the gel fraction or storage modulus of the adhesive after active energy ray curing. Under high temperature and high humidity conditions, From the viewpoint of better unevenness following and blistering resistance, the lower limit is preferably 1 part by mass or more, and particularly preferably 3 parts by mass or more, based on 100 parts by mass of the (meth)acrylate polymer (A). , 4 parts by mass or more is better. On the other hand, from the viewpoint of the adhesive force of the adhesive after hardening by active energy rays, the upper limit of the content is preferably 20 parts by mass or less, particularly preferably 12 parts by mass or less, and more preferably 8 parts by mass or less.

(1-5) Photopolymerization initiator (E) When ultraviolet rays are used as active energy rays to harden the adhesive composition P, it is preferable that the adhesive composition P further contains a photopolymerization initiator (E). By containing such a photopolymerization initiator (E), the active energy ray curable component (D) can be efficiently polymerized, and the polymerization curing time and the amount of active energy ray irradiation can be reduced.

Such photopolymerization initiator (E) includes, for example, benzoin (benzoin), benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, and acetophenone (acetophenone), dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- 2-Methyl-1-phenylpropanyl-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-propanol -1 ketone, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, benzophenone, p-phenyldiphenylketone, 4,4' -Diethylaminodiphenylketone, bicyclic diphenylketone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary butylanthraquinone, 2-aminoanthraquinone, 2- Methylthioxanthone (2-methyl thioxanthone), 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-methylethylene base) phenyl] acetone], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine Oxides etc. These can be used individually or in combination of 2 or more types.

Among these, a phosphine oxide-based photopolymerization initiator that is easily decomposed even when ultraviolet rays are irradiated through a plastic plate containing an ultraviolet absorber and easily hardens the adhesive reliably is preferred. Specifically, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc. are preferred. .

In the adhesive composition P, the lower limit of the content of the photopolymerization initiator (E) relative to 100 parts by mass of the active energy ray curable component (D) is preferably 0.1 part by mass or more, and particularly preferably 1 part by mass or more. , more than 5 parts by mass is better. The upper limit is preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and more 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 preferably 0.3 or more, and more preferably 0.6 or more. Furthermore, the mass ratio is preferably 10 or less, more preferably 5 or less, particularly preferably 2 or less, and more preferably 1 or less. Since the mass ratio of the amount of the photopolymerization initiator (E) to the amount of the colorant (C) is within the above range, the total light transmittance and the haze value can be controlled within a preferred range, and an adhesive having a suitable gel fraction, storage modulus and adhesion can be easily obtained through active energy ray curing, and the unevenness following property and blister resistance under high temperature and high humidity conditions are easily better.

(1-6) Various additives Various additives commonly used in acrylic adhesives may be added to the adhesive composition P as needed, such as silane coupling agents, rust inhibitors, ultraviolet absorbers, antistatic agents, tackifiers, antioxidants, light stabilizers, and softeners. , refractive index adjusters, etc. The additives constituting the adhesive composition P do not include a polymerization solvent or a dilution solvent described below.

Among the above, it is preferable that the adhesive composition P contains a silane coupling agent. Therefore, even if the adherend is a plastic plate or glass component, it can have improved adhesion to the adherend and better unevenness following and blistering resistance under high temperature and high humidity conditions.

The silane coupling agent is an organosilicon compound having at least one alkoxysilyl group in the molecule, preferably one that has good compatibility with the (meth)acrylate polymer (A) and has light transmittance.

Examples of such silane coupling agents include silicon compounds containing polymerizable unsaturated groups such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; 3-epoxy Silicon compounds with epoxy structures such as propoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-Mercaptopropyltriethoxysilane, 3-Mercaptopropyldimethoxymethylsilane and other thiol-containing silicon compounds; 3-Aminopropyltrimethoxysilane, N-(2-aminoethyl Silicon compounds containing amine groups such as N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc.; 3-chloro Propyltrimethoxysilane, 3-isocyanate propyltriethoxysilane; or at least one of these and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyl Condensates of alkyl group-containing silicon compounds such as trimethoxysilane, etc. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the silane coupling agent in the adhesive composition P is preferably 0.01 part by mass or more, particularly preferably 0.05 part by mass or more, and more preferably 0.1 part by mass or more based on 100 parts by mass of the (meth)acrylate polymer (A). good. In addition, the content is preferably 1.2 parts by mass or less, particularly preferably 0.8 parts by mass or less, and more preferably 0.4 parts by mass or less.

(2) Preparation of adhesive composition The adhesive composition P can be prepared by producing a (meth)acrylate polymer (A), mixing the obtained (meth)acrylate polymer (A) and a cross-linking agent (B), and adding active energy rays if necessary. It is manufactured from curing component (D), photopolymerization initiator (E), additives, etc. In the case of the colored adhesive layer 111, a colorant (C) is further blended.

The (meth)acrylate polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a general radical polymerization method. The (meth)acrylate polymer (A) is preferably polymerized by a solution polymerization method using a polymerization initiator as necessary. However, the present invention is not limited to this, and polymerization may be performed without a solvent. Examples of the polymerization solution include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like, and two or more types may be used in combination.

Examples of polymerization initiators include azo compounds, organic peroxides, and the like, and two or more types may be used in combination. Azo compounds such as 2,2'-Azobisisobutyronitrile, 2,2'-Azobis(2-methylbutyronitrile), 1,1'-Azobis(cyclohexane 1-carbon nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), di Methyl 2,2'-azobis (2-methylpropyl ester), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethyl propionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], etc.

Organic peroxides such as benzoyl peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, peroxybenzoate Di(2-ethoxyethyl) dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexyl) peroxide , dipropionyl peroxide, diacetyl peroxide, etc.

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

After obtaining the (meth)acrylate polymer (A), add the cross-linking agent (B) to the solution of the (meth)acrylate polymer (A), and if necessary, add the diluting solvent, colorant (C), and reactive The energy ray curable component (D), photopolymerization initiator (E), additives, etc. are thoroughly mixed to obtain an adhesive composition P (coating solution) diluted with a solvent. In addition, if any of the above components precipitates when used in a solid state or when mixed with other components in an undiluted state, the component can be dissolved alone or diluted in a diluting solvent in advance, and then mixed with other components.

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

The concentration and viscosity of the coating solution prepared in this way are not particularly limited as long as they are within the range that can be applied, and can be appropriately selected depending on the situation. For example, the concentration of the adhesive composition P is diluted to 10 to 60% by mass. In addition, when obtaining the coating solution, the addition of a diluent solution or the like is not necessary. If the adhesive composition P has a coating viscosity, etc., the dilution solvent does not need to be added. In this case, the adhesive composition P is a coating solvent using the polymerization solvent of the (meth)acrylate polymer (A) directly as a diluting solvent.

(3) Formation of adhesive layer The colored adhesive layer 111 and the colorless adhesive layer 112 of this embodiment are each preferably formed of an adhesive that crosslinks the adhesive composition P (coating layer). Crosslinking of the adhesive composition P can usually be carried out via heat treatment. In addition, this heat treatment may be performed together with the drying treatment when evaporating the diluting 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, and particularly preferably 70 to 120°C. In addition, the heating time is 10 seconds to 10 minutes, and 50 seconds to 2 minutes is particularly good.

After heat treatment, a hardening time of about 1 to 2 weeks at normal temperature (for example, 23°C, 50% RH) may be provided if necessary. In the case where this hardening time is necessary, the adhesive is formed after the hardening period has passed, and in the case where the hardening time is not required, the adhesive is formed after the heat treatment is completed.

Through the above-mentioned heat treatment (and hardening), the (meth)acrylate polymer (A) is fully cross-linked through the cross-linking agent (B).

The adhesive layer 11 of this embodiment can be obtained by laminating a colored adhesive layer 111 and a colorless adhesive layer 112 . The timing of lamination may be before hardening each adhesive layer or after hardening. However, in order to further increase the adhesion of the colored adhesive layer 111 and the colorless adhesive layer 112, it is preferable to laminate each adhesive layer before hardening.

(4) Physical properties of adhesive It is preferable that the adhesive agent of this embodiment has the following physical properties. (4-1) Gel fraction The gel fraction of both the colored adhesive layer 111 and the colorless adhesive layer 112 is preferably a lower limit value of 20% or more, more preferably 40% or more, particularly preferably 50% or more, and more preferably 52% or more. good. In addition, the upper limit of the gel fraction is preferably 100% or less, more preferably 80% or less, particularly preferably 70% or less, more preferably 60% or less, and most preferably 55% or less. When the gel fraction of the adhesive is in the above range, the adhesive exhibits good cohesion and has excellent unevenness following and blistering resistance under high temperature and high humidity conditions. In addition, it exhibits good adhesion and better adhesion to the adherend. Here, the method of measuring the gel fraction of the adhesive is as shown in the test example described below.

In the case of an active energy ray-curable adhesive, the lower limit of the gel fraction of the active energy ray-cured adhesive is preferably 40% or more, more preferably 50% or more, particularly preferably 60% or more, and 65%. The above is better. In addition, the upper limit of the gel fraction is preferably 100% or less, more preferably 90% or less, particularly preferably 80% or less, more preferably 75% or less, and most preferably 71% or less. When the gel fraction of the adhesive cured by active energy rays is within the above range, the unevenness following and blistering resistance under high temperature and high humidity conditions will be more excellent. In addition, it exhibits good adhesion and better adhesion to the adherend.

(4-2) Storage modulus The lower limit of the storage modulus at 23°C of the adhesive constituting the colored adhesive layer 111 is preferably 0.01 MPa or more, 0.02 MPa or more is more preferred, 0.04 MPa or more is particularly preferred, and 0.06 MPa or more is more preferred. Since the lower limit of the storage modulus is as described above, it is excellent in blistering resistance. In addition, when the colorless adhesive layer 112 of the adhesive sheet 11 of this embodiment contacts and follows the unevenness of the adherend, it is compressed or deformed due to the unevenness of the adherend. For this reason, there is a possibility that the colored adhesive layer 111 is affected by compression or deformation of the colorless adhesive layer 112 (that is, uneven transmittance occurs). However, since the lower limit of the storage modulus is the above, The colored adhesive layer 111 is hardly affected by compression or deformation of the colorless adhesive layer 112, and it is easy to control the light transmittance described below to a desired value. Therefore, the effect of suppressing uneven transmittance is even more excellent.

The upper limit of the storage modulus is preferably 1 MPa or less, more preferably 0.5 MPa or less, particularly preferably 0.2 MPa or less, and more preferably 0.1 MPa or less. Since the upper limit of the storage modulus is as described above, it exhibits good adhesive force and has better adhesion to the adherend.

On the other hand, the lower limit of the storage modulus at 23° C. of the adhesive constituting the colorless adhesive layer 112 is preferably 0.01 MPa or more, particularly preferably 0.02 MPa or more, and more preferably 0.04 MPa or more. Since the lower limit of the storage modulus is as described above, it is excellent in unevenness following properties and blistering resistance under high temperature and high humidity conditions.

The upper limit of the storage modulus is preferably 1 MPa or less, more preferably 0.5 MPa or less, particularly preferably 0.2 MPa or less, more preferably 0.1 MPa or less, and most preferably 0.05 MPa or less. Since the upper limit of the storage modulus is the above value, the initial unevenness following properties are excellent. In addition, the unevenness of the adherend can be absorbed through the colorless adhesive layer 112, which more effectively prevents the colored adhesive layer 111 from being compressed or deformed due to the unevenness. Therefore, the beam transmittance described below can be controlled to a desired value. Therefore, uneven transmittance of the adhesive layer 11 is more effectively suppressed.

When the adhesive constituting the colored adhesive layer 111 is an active energy ray-curable adhesive, the lower limit of the storage modulus of the adhesive at 23°C after active energy ray curing is preferably 0.05 MPa or more, 0.09 MPa or above is preferred, 0.12MPa or above is particularly preferred, and 0.15MPa or above is even more preferred. Since the lower limit of the storage modulus is the above value, it is excellent in blistering resistance. In addition, the upper limit of the storage modulus is preferably 2 MPa or less, more preferably 1 MPa or less, particularly preferably 0.5 MPa or less, and more preferably 0.2 MPa or less. Since the upper limit of the storage modulus is the above-mentioned value, the adhesive force exhibits good adhesion and the adhesion to the adherend is better.

On the other hand, when the adhesive constituting the colorless adhesive layer 112 is an active energy ray-curable adhesive, the lower limit of the storage modulus of the adhesive at 23° C. after active energy ray curing is 0.05 MPa or more. It is better, above 0.08MPa is particularly good, and above 0.12MPa is even better. Since the lower limit of the storage modulus is the above value, it is excellent in unevenness following properties and blistering resistance under high-temperature and high-humidity conditions. In addition, the upper limit of the storage modulus is preferably 2 MPa or less, more preferably 1 MPa or less, particularly preferably 0.5 MPa or less, and more preferably 0.2 MPa or less. Since the upper limit of the storage modulus is the above-mentioned value, the adhesive force exhibits good adhesion and the adhesion to the adherend is better.

When the storage modulus of the adhesive constituting the colored adhesive layer 111 at 23°C is G1 and the storage modulus of the adhesive constituting the colorless adhesive layer 112 at 23°C is G2, it is better for G1 and G2 to satisfy the following relational expression. G1≧G2 By satisfying the above relational expression, when the colorless adhesive layer 112 of the adhesive sheet 11 of this embodiment contacts and follows the unevenness of the adherend, the colorless adhesive layer 112 is compressed or deformed due to the unevenness of the adherend. It is difficult to provide the influence to the colored adhesive layer 111, making it easy to control the beam transmittance described below to a desired value, and the effect of suppressing uneven transmittance is better. From this point of view, it is better for G1 and G2 to satisfy the following relational expression. G1>G2

In addition, the storage modulus in this manual is the value measured by the torsional shear test at a measurement frequency of 1Hz in accordance with JIS K7244-6. The details are shown in the test examples described later.

(5) Thickness of adhesive layer The thickness of the colored adhesive layer 111 can be a thickness that obtains desired optical properties (including the degree of coloring). Generally, the lower limit is preferably 5 μm or more, more preferably 20 μm or more, particularly preferably 40 μm or more, and more preferably 50 μm or more. When the thickness of the colored adhesive layer 111 is as described above, it is easy to obtain desired optical properties and to exhibit desired adhesive force due to the relationship between the transmission and the content of the colorant (C).

In addition, 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 more preferably 75 μm or less. When the upper limit of the thickness of the colored adhesive layer 111 is the above, the thickness of the adhesive layer 11 is likely to be appropriate. In addition, the desired optical properties are easily obtained due to the relationship between the transmission and the content of the colorant (C). In addition, 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, as mentioned above, the thickness of the colorless adhesive layer 112 (the colorless adhesive layer located in contact with the concavities and convexities of the adherend) is preferably greater than the depth or height of the concavities and convexities of the adherend. Generally, the lower limit value is preferably 10 μm or more, more preferably 30 μm or more, particularly preferably 40 μm or more, and more preferably 50 μm or more. When the lower limit of the thickness of the colorless adhesive layer 112 is the above, the unevenness of the adherend can be absorbed by the colorless adhesive layer 112 , which more effectively prevents the colored adhesive layer 111 from being compressed or deformed due to the unevenness. Therefore, it becomes easy to control the beam transmittance described below to a desired value. Therefore, uneven transmittance in the adhesive layer 11 is more effectively suppressed.

In addition, 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 more preferably 75 μm or less. When the upper limit of the thickness of the colorless adhesive layer 112 is as described above, the thickness of the adhesive layer 11 can be easily formed to an appropriate thickness. In addition, 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 adhesive layer that is not located on the uneven surface of the adherend is not limited to the above range, and can be set to a desired thickness.

The thickness of the adhesive layer 11 can be appropriately set depending on the application. Generally, the lower limit is preferably 50 μm or more, 80 μm or more is more preferred, 100 μm or more is particularly preferred, and 150 μm or more is more preferred. When the lower limit of the thickness of the adhesive layer 11 is the above, it is easy to obtain desired adhesive force and excellent unevenness following properties.

The upper limit of the thickness of the adhesive layer 11 is preferably 500 μm or less, more preferably 300 μm or less, particularly preferably 250 μm or less, and more preferably 200 μm or less. When the upper limit of the thickness of the adhesive layer 11 is the above, workability is good, and appearance problems such as dents are less likely to occur.

1-2. Peel-off sheet The peeling 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 of this embodiment, one or both of the release sheets 12a and 12b are not necessarily necessary.

As the release sheets 12a and 12b, for example, polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film can be used. Diester film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene. (Meth)acrylic acid copolymer film, ethylene. (Meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. In addition, these cross-linked films can also be used. Furthermore, these laminated films can also be used.

It is preferable to perform the peeling process on the peeling surface of the above-mentioned peeling sheets 12a, 12b (especially the side in contact with the adhesive layer 11). Examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, wax-based release agents, and the like. Moreover, among the release sheets 12a and 12b, the release sheet on the side peeled off first from the adhesive layer 11 is a light release type release sheet with a small peeling force, and the release sheet on the side peeled off later is a heavy release type release sheet with a large peeling force. A peel-off piece is preferred.

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

2.Physical properties (1) Total light transmittance The total light transmittance of the colored adhesive layer 111 (the value measured based on JIS K7361-1:1997; the same below) is preferably 3% or more in the lower limit, preferably 10% or more, particularly preferably 30% or more, 45 % or above is better. Since the total light transmittance of the colored adhesive layer 111 is as described above, visibility as a display body can be easily ensured. On the other hand, the upper limit of the total light transmittance of the colored adhesive layer 111 is not particularly limited, but is usually 100% or less. When considering concealment, 90% or less is preferred, 80% or less is more preferred, and 70% or less is preferred. Very good, preferably below 60%.

The total light transmittance of the colorless adhesive layer 112 is preferably 80% or more, more preferably 90% or more, particularly preferably 95% or more, and more preferably 99% or more. When the total light transmittance of the colorless adhesive layer 112 is as described above, the adhesive layer 11 has high transparency and 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, and it is easy to control the light transmittance described below as the adhesive layer 11 at the desired position. The higher the numerical value, the better the effect of suppressing uneven transmittance. In addition, the upper limit of the total light transmittance of the colorless adhesive layer 112 is not particularly limited, but 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 more preferably 40% or more. Since the total light transmittance of the adhesive layer 11 is as described above, the display has good visibility. On the other hand, the upper limit of the total light transmittance of the adhesive layer 11 is not particularly limited, but is usually 100% or less. From the viewpoint of good concealment, it is preferably 90% or less, more preferably 75% or less, and 65%. The following is particularly preferred, and below 55% is even better.

Furthermore, when the adhesive layer is active energy ray hardenable, the total light transmittance of the adhesive layer does not substantially change before active energy ray hardening and after active energy ray hardening.

(2) Haze value The haze value of the colored adhesive layer 111 (a value measured based on JIS K7136:2000; the same below) is preferably 0.5% or more, more preferably 1% or more, particularly preferably 1.6% or more, and more preferably 2.2% or more. good. Since the haze value of the colored adhesive layer 111 is the above, it is easy to obtain a desired coloring degree. For example, the obtained display body can easily provide a sense of integration with peripheral components (such as frames), making it excellent in concealment. On the other hand, the upper limit of the haze value of the colored adhesive layer 111 is preferably 60% or less, more preferably 40% or less, particularly preferably 25% or less, and more preferably 10% or less. Since the haze value of the colored adhesive layer 111 is as described above, the visibility of the display body 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 more preferably 0.2% or less. When the haze value of the colorless adhesive layer 112 is the above, the transparency is high and the adhesive layer 11 is suitable for optical applications (for displays). In addition, the lower limit of the haze value of the colorless adhesive layer 112 is usually 0% or more.

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 more preferably 10% or less. Since the haze value of the adhesive layer 11 is as described above, the visibility of the display body is good. On the other hand, when 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, more preferably 1% or more, particularly preferably 2% or more, and 2.5% or more. Better. Therefore, it is easy to obtain a desired coloring degree, for example, it is easy to provide the display with a sense of integration with surrounding components (such as frame materials).

Furthermore, when the adhesive layer has active energy ray hardening properties, the haze value of the adhesive layer does not substantially change before active energy ray hardening and after active energy ray hardening.

The above optical characteristics can be achieved by appropriately selecting the type and content of the colorant (C) contained in the adhesive constituting the colored adhesive layer 111 .

(3) Adhesion The adhesion force of the colored adhesive layer 111 to the soda-lime glass has a lower limit value of 10N/25mm or more, preferably 20N/25mm or more, 30N/25mm or more, particularly preferably 40N/25mm or more. When the lower limit of the adhesive force is as described above, the foaming resistance is excellent. In addition, the upper limit of the adhesion force of the colored adhesive layer 111 to the soda-lime glass is preferably 90N/25mm or less, more preferably 70N/25mm or less, and particularly preferably 50N/25mm or less. When the upper limit of the adhesive force is the above, good reworkability can be obtained, and in the event of a lamination error, the display component, especially the expensive display component, can be reused.

When the adhesive constituting the colored adhesive layer 111 is an active energy ray-curable adhesive, the adhesive force of the colored adhesive layer 111 after active energy ray curing is preferably 20N/25mm or more, 30N/ 25mm or above is particularly good, 40N/25mm or above is even better. When the lower limit of the adhesive force is as described above, the foaming resistance is excellent. In addition, the upper limit of the adhesion force of the colored adhesive layer 111 hardened by active energy rays to soda-lime glass is preferably 100N/25mm or less, more preferably 75N/25mm or less, and particularly preferably 50N/25mm or less. When the upper limit of the adhesive force is the above, good reworkability can be obtained, and in the event of a lamination error, the display component, especially the expensive display component, can be reused.

The adhesion force of the colorless adhesive layer 112 to the soda-lime glass has a lower limit of 10N/25mm or more, preferably 20N/25mm or more, 30N/25mm or more, and 40N/25mm or more. When the lower limit of the adhesive force is the above, it becomes one with excellent unevenness following properties under high temperature and high humidity conditions. In addition, the upper limit of the adhesion force of the colorless adhesive layer 112 to the soda-lime glass is preferably 90N/25mm or less, more preferably 70N/25mm or less, and particularly preferably 50N/25mm or less. When the upper limit of the adhesive force is the above, good reworkability can be obtained.

When the adhesive constituting the colorless adhesive layer 112 is an active energy ray-curable adhesive, the adhesive force of the colorless adhesive layer 112 after active energy ray curing to the soda-lime glass has a lower limit of 20N/25mm or more. Best, 30N/25mm or above is particularly good, 40N/25mm or above is even better. When the lower limit of the adhesive force is the above, it becomes one with excellent unevenness following and blistering resistance under high-temperature and high-humidity conditions. In addition, the upper limit of the adhesion force of the colorless adhesive layer 112 hardened by active energy rays to soda-lime glass is preferably 100N/25mm or less, preferably 75N/25mm or less, and particularly preferably 50N/25mm or less. When the upper limit of the adhesive force is the above, good reworkability can be obtained.

The adhesion force of the adhesive sheet 1 of this embodiment to soda-lime glass has a lower limit value of preferably 10N/25mm or more, more preferably 20N/25mm or more, particularly preferably 30N/25mm or more, and more preferably 40N/25mm or more. When the lower limit of the adhesive force is the above, it becomes one with excellent unevenness following and blistering resistance under high-temperature and high-humidity conditions. In addition, the upper limit of the adhesive force of the adhesive sheet 1 of this embodiment to soda-lime glass is preferably 90N/25mm or less, more preferably 70N/25mm or less, particularly preferably 60N/25mm or less, and more preferably 50N/25mm or less. When the upper limit of the adhesive force is the above, good reworkability can be obtained, and in the event of a lamination error, the display component, especially the expensive display component, can be reused.

When the adhesive constituting the colored adhesive layer 111 or the colorless adhesive layer 112 is an active energy ray-curable adhesive, the adhesive force of the adhesive sheet 1 after active energy ray curing to soda-lime glass has a lower limit of 20N /25mm or above is preferred, 30N/25mm or above is particularly good, 40N/25mm or above is even better. When the lower limit of the adhesive force is the above, it becomes one with excellent unevenness following and blistering resistance under high-temperature and high-humidity conditions. In addition, the upper limit of the adhesion force of the adhesive sheet 1 to soda-lime glass after hardening by active energy rays is preferably 100N/25mm or less, more preferably 75N/25mm or less, particularly preferably 65N/25mm or less, and even more preferably 55N/25mm or less. . When the upper limit of the adhesive force is the above, good reworkability can be obtained, and in the event of a lamination error, the display component, especially the expensive display component, can be reused.

Here, the adhesive force in this manual is basically the adhesive force measured by the 180-degree peel method in accordance with JIS Z0237:2009. However, the measurement sample is 25mm wide and 100mm long. The measurement sample is attached to the adherend. The measurement is based on 0.5 MPa, 50°C for 20 minutes, then left for 24 hours under normal pressure, 23°C, 50% RH, and measured at a peeling speed of 300mm/min.

(4) Bump following rate The ability of the adhesive layer to follow the unevenness of the adherend, that is, the unevenness following ability, can be judged by the unevenness following rate (%) as an index. As for the unevenness following rate of the colorless adhesive layer 112 represented by the following formula, the lower limit is preferably 20% or more, particularly preferably 30% or more, and more preferably 40% or more. In addition, the upper limit of the unevenness following rate is not particularly limited, but it is generally preferably 80% or less, and particularly preferably 70% or less.

On the other hand, although the unevenness following rate (%) of the colored adhesive layer 111 is not necessarily as high as the unevenness following rate of the colorless adhesive layer 112, the lower limit is preferably 20% or more, and 30% or more is particularly preferred. 40 % or above is better. In addition, the upper limit of the unevenness following rate is not particularly limited, but it is generally preferably 80% or less, and particularly preferably 70% or less.

Concave and convex following rate (%) = {(After the predetermined durability test, the height of the height difference between the high and low planes that still maintains the buried state without bubbles, floating, peeling, etc. (μm) / (Thickness of the adhesive layer)} × 100 The test method of the concavity and convexity following rate is shown in the test example described later. In the case of an active energy ray-curable adhesive, it is the unevenness following rate when the adhesive is cured by active energy rays after being attached to the adherend.

3. Manufacturing of adhesive sheets An example of manufacturing the adhesive sheet 1 is to apply a coating solution of the adhesive composition P for forming the colorless adhesive layer 112 on the peeling surface of the release sheet 12a, and perform heat treatment to heat the adhesive composition P. Cross-linking is performed to form a coating layer, and a release sheet 12a with the coating layer is obtained. Furthermore, on the peeling surface of the other peeling sheet 12b, a coating solution of the adhesive composition P for forming the colored adhesive layer 111 is applied, and heat treatment is performed to thermally cross-link the adhesive composition P to form a coating. layer to obtain a peeling sheet 12b with a coating layer. Thereafter, the peeling sheet 12a with the coating layer and the peeling sheet 12b with the coating layer are bonded together with the coating layers of both being in contact with each other. In this way, a plurality of release sheets with coating layers can be produced, and the coating layers can be bonded together in a desired number and in a desired lamination order. When the curing time is necessary, after the curing time has passed, and when the curing time is not required, the laminated coating layer is directly used as the adhesive layer 11. Therefore, the above-mentioned adhesive sheet 1 having the adhesive layer 11 which is a laminate of the colored adhesive layer 111 and the colorless adhesive layer 112 is obtained. The conditions for heat treatment and hardening are as described above.

The coating layer used to form the colorless adhesive layer 112 and the coating layer used to form the colored adhesive layer 111 can each be sandwiched between two peeling sheets, or they can be used to form the colorless adhesive layer after being laminated together. When the coating layer 112 and the coating layer used to form the colored adhesive layer 111 are peeled off, a release sheet is peeled off.

As a method of applying the coating solution of the adhesive composition P, a rod coating method, a knife coating method, a roll coating method, a blade coating method, a nozzle coating method, a gravure coating method, etc. can be used.

[display body] Types of displays (displays) in this embodiment include, for example, vehicle mounting panels, car navigation systems, various counters installed on dashboards, displays for general users such as tablet terminals, and commercial displays. Displays such as tablet terminals or digital signage, displays such as digital signage for outdoor use, etc. These displays are required to have an appearance that is consistent with surrounding components or have a high-end feel. However, the display of the present invention is not limited to these.

As shown in FIG. 2 , a display 2A according to an embodiment includes a first display component 21 (a display component), a second display component 22 (another display component), and a etc., the first display component 21 and the second display component 22 are bonded to each other by the adhesive layer 11 .

One of the first display component 21 and the second display component 22 may have unevenness on the surface bonded via the adhesive layer 11 . In the embodiment shown in FIG. 2 , the first display component 21 has unevenness caused by the printing layer 23 on one surface of the adhesive 11 .

The adhesive layer 11 in the display 2A is the adhesive layer 11 of the adhesive sheet 1 . The adhesive layer 11 of this embodiment is a laminate of a colored adhesive layer 111 and a colorless adhesive layer 112 . The colorless adhesive layer 112 is located on the side that is in contact with the unevenness caused by the printing layer 23 .

The display body 2A may be a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic light emitting diode (organic EL) display, an e-book, etc., or may be a touch panel.

The first display component 21 is preferably a protective panel composed of a laminate or the like including a glass plate, a plastic plate, or the like. In this case, the printing layer 23 generally forms a frame shape on the adhesive layer 11 side of the first display component 21 .

The above-mentioned glass plate is not particularly limited, such as chemically strengthened glass, alkali-free glass, quartz glass, soda-lime glass, barium-containing glass. Strontium glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

The above-mentioned plastic board is not particularly limited, such as acrylic board, polycarbonate board, etc. The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

In addition, various functional layers (transparent conductive film, metal layer, silicon oxide layer, hard coating layer, anti-glare film layer, etc.) can be provided on one or both sides of the above-mentioned glass plate or plastic plate, and optical elements can also be laminated. In addition, the transparent conductive film and the metal layer can also be patterned.

The second display component 22 is an optical component to which the first display component 21 should be attached, a display module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, or an organic light emitting diode). (organic EL) module, etc.), an optical element that is a part of a display module, or a laminate including a display module is preferred.

The above-mentioned optical elements include anti-scatter film, polarizing plate (polarizing film), polarizer, retardation plate (retardation film), viewing angle compensation film, brightness enhancement film, contrast enhancement film, liquid crystal polymer film, diffusion film, semi-transmission reflection film, transparent conductive film, etc. The anti-scatter film may be 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 can be used. The lower limit of the thickness of the printing layer 23, that is, the height of the level difference, 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. Since the lower limit value is the above, it is possible to sufficiently ensure the concealment of electrical wiring and the like from the viewer's side. Moreover, the upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and more preferably 20 μm or less. Since the upper limit is the above, it is possible to prevent the adhesive layer 11 from deteriorating in the conformability of the printing layer 23 to the unevenness, and to suppress uneven transmittance.

In manufacturing the display 2A, one example is to peel off the peeling sheet 12a of the adhesive sheet 1, and attach the exposed colorless adhesive layer 112 of the adhesive sheet 1 to the side surface where the printed layer 23 of the first display component 21 exists. combine.

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 component element 22 are bonded together. In addition, in other examples, the order of laminating the first display component 21 and the second display component 22 can be changed.

When the adhesive layer 11 is active energy ray curable, after the first display component 21 and the second display component 22 are bonded together through the adhesive layer 11 as described above, the active energy is irradiated to the adhesive layer 11 String. Therefore, the energy ray curable component (C) in the adhesive layer 11 is polymerized, and the adhesive layer 11 is hardened. Energy rays are irradiated to the adhesive layer 11 usually through either the first display component 21 or the second display component 22, preferably through the first display component 21 as the protective panel. conduct.

Active energy rays refer to electromagnetic waves or charged particle rays that contain energy quanta, such as ultraviolet rays or electron rays. Among active energy rays, easy-to-obtain ultraviolet rays are particularly good.

Ultraviolet irradiation can be carried out through high-pressure mercury lamps, electrodeless H lamps, xenon lamps, etc. The amount of ultraviolet irradiation is preferably about 50 to 1000 mW/cm ² , and preferably about 100 to 500 mW/cm ² . In addition, 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 through an electron beam accelerator or the like, and the electron beam irradiation dose is preferably about 10 to 1000 krad.

In the above-mentioned display 2A, the colorless adhesive layer 112 is laminated on the surface having the unevenness caused by the printing layer 23 of the first display component 21. Since the unevenness is absorbed by the colorless adhesive layer 112, the colorless adhesive layer 112 can absorb the unevenness. The colored adhesive layer 111 is suppressed from being compressed or deformed. Therefore, uneven transmittance of the adhesive layer 11 can be suppressed, and occurrence of bright spots on the display 2A can be suppressed.

In the display 2A described above, when the adhesive layer 11 is formed of the adhesive composition P, the adhesive layer 11 has excellent unevenness following properties or blistering resistance under high-temperature and high-humidity conditions. Therefore, the display 2A Even if it is placed under high temperature and high humidity conditions (such as 85°C, 85% RH), floating, peeling, etc. will be suppressed.

As shown in FIG. 3 , a display 2B according to another embodiment has a backlight 30 , an adhesive layer 11 laminated on the backlight 30 , a diffusion element 41 laminated on the adhesive layer 11 , and a diffusion element 41 laminated on the adhesive layer 11 . It is composed of a liquid crystal panel 42 on. Here, the backlight 30 of the display 2B corresponds to the first display component, and the laminated body including the diffusion element 41 and the liquid crystal panel 42 corresponds to the second display component.

The backlight 30 is composed of one or more substrates 31 and a plurality of luminous bodies 32 provided on the substrates 31 . Such a backlight 30 has unevenness caused by the plurality of light emitters 32 .

The adhesive layer 11 in the display 2B is the adhesive layer 11 of the adhesive sheet 1 . The adhesive layer 11 of this embodiment is a laminate of a colored adhesive layer 111 and a colorless adhesive layer 112 . The colorless adhesive layer 112 is located on the side that is in contact with the unevenness caused by the luminous body 32 . The plurality of luminous bodies 32 are sealed without gaps due to the colorless adhesive layer 112 . Therefore, no air layer or voids are formed inside the obtained display, and thus deterioration in image quality due to light reflection loss can be prevented.

The substrate 31 is generally used for backlights and is not particularly limited. This substrate 31 is usually a printed circuit board (PCB substrate; Printed Circuit Board).

The substrate 31 may be integrally formed by mounting a plurality of luminous bodies 32 , or may be mounted with one luminous body 32 on one substrate 31 and formed separately. In the case of separate formation, each substrate 31 is usually fixed to a frame, a support, a frame, or the like. In this embodiment, as shown in FIG. 3 , it is preferable that the substrate 31 is mounted with a plurality of light emitters 32 and is integrally formed.

A reflective layer may be formed on the surface of the base material 31 on the adhesive layer 11 side, or a reflective element may be provided. Therefore, the brightness generated by the backlight 30 can be effectively improved. The materials of the reflective layer or the reflective element can be made of publicly known materials.

Types of the light-emitting body 32 include, for example, light-emitting diodes (LEDs), laser diodes (LD), organic light-emitting diode light-emitting elements, inorganic light-emitting diode light-emitting elements, and the like. Among these, from the viewpoint of the encapsulation properties of the adhesive layer 11, LED is preferred, and mini LED or micro LED is particularly preferred.

The thickness of the luminous body 32 is preferably 10 μm or more, more preferably 30 μm or more, particularly preferably 50 μm or more, and more preferably 80 μm or more. In addition, the thickness of the luminous body 32 is preferably 300 μm or less, particularly preferably 150 μm or less, and more preferably 100 μm or less.

In addition, the gap width between adjacent luminous bodies 32 is preferably 0.01 mm or more, particularly preferably 0.1 mm or more, and more preferably 0.5 mm or more. In addition, the above-mentioned gap width is preferably 100 mm or less, more preferably 10 mm or less, particularly preferably 4 mm or less, and more preferably 2 mm or less.

The shape of the luminous body 32 is not particularly limited, and is usually rectangular, hemispherical, or the like. The size of the luminous body 32 is not particularly limited. However, from the viewpoint of packaging properties of the luminous body, one side or diameter of the viewing plane is preferably 0.01 to 100 mm, more preferably 0.1 to 10 mm, particularly preferably 0.2 to 5 mm, and more preferably 0.5 to 2 mm. .

The diffusion element 41 is an element that diffuses the light irradiated by the backlight 30 . Through this diffusion element 41 , the occurrence of bright spots can be effectively suppressed. The diffusion element 41 can be a publicly known one, and for example, a diffusion plate, a diffusion film, a combination thereof, etc. can be used. The liquid crystal panel 42 may be a publicly known one.

In addition, desired optical elements can be provided between the adhesive layer 11 and the diffusion element 41, between the diffusion element 41 and the liquid crystal panel 42, or on the surface of the liquid crystal panel 42 opposite to the diffusion element 41. Such optical elements include brightness enhancement films, contrast enhancement films, viewing angle compensation films, transparent conductive films, liquid crystal polymer films, semi-transflective films, anti-scattering films, etc.

In manufacturing the display 2B of this embodiment, for example, one release sheet 12 a of the adhesive sheet 1 is peeled off, and the exposed colorless adhesive layer 112 of the adhesive sheet 1 is bonded to the side surface of the backlight 30 on which the luminous body 32 exists.

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 element 41 are bonded together. When the adhesive layer 11 has active energy ray curability, the adhesive layer 11 is irradiated with active energy rays. The irradiation conditions of active energy rays and other conditions are the same as those of the display body 2A.

Thereafter, the diffusion element 41 and the liquid crystal panel 42 are bonded together using a desired adhesive sheet. In other examples, the order of laminating the backlight 30 and the diffusion element 41 can also be changed.

In the display 2B described above, the colorless adhesive layer 112 is laminated on the surface having the unevenness caused by the light emitting body 32 of the backlight 30. The colorless adhesive layer 112 absorbs the unevenness, thereby suppressing the formation of colored adhesive. Layer 111 is compressed or deformed. Therefore, uneven transmittance in the adhesive layer 11 can be suppressed, and the occurrence of bright spots in the display 2B can be suppressed.

In the display 2B described above, when the adhesive layer 11 is formed of the adhesive composition P, the adhesive layer 11 has excellent unevenness following properties or blistering resistance under high-temperature and high-humidity conditions. Therefore, the display body For example, 2B can suppress floating, peeling, etc. even when placed under high temperature and high humidity conditions (such as 85°C, 85% RH).

Here, a display (including the above-mentioned displays 2A and 2B) according to an embodiment of the present invention has one display component, other display components, and an adhesive layer that adheres these components to each other. A display At least one of the constituent elements and other display constituent elements has an uneven surface on the side that is bonded via an adhesive layer, and the adhesive layer has at least one colored adhesive layer, and the light beam in the vicinity of the uneven areas is transmitted through The ratio of the rate and the beam transmittance in the flat area (beam transmittance in the vicinity of the concave and convex areas/beam transmittance in the flat area) is preferably 0.980 or more, 0.986 or more is particularly preferred, and 0.990 or more is even more preferred. The upper limit value is 1 which is the best.

In addition, the difference of the light beam transmittance in the flat area minus the light beam transmittance in the vicinity of the uneven areas is preferably 1 point or less, more preferably 0.9 points or less, particularly preferably 0.7 points or less, and more preferably 0.5 points or less. The lower limit value is 0 points.

Since the display body has the above-mentioned structure and physical properties, the transmittance unevenness is small, and thus the occurrence of bright spots in the display body is suppressed. In addition, the above-mentioned "parts near the unevenness" specifically refers to the part within 10 mm in the plane direction from the position of the level difference caused by the unevenness. The above-mentioned "flat portion" refers to a portion that is not affected by the unevenness and is sufficiently far away from the unevenness in the planar direction. In addition, the above-mentioned "beam transmittance" refers to the transmittance when the beam size of the transmitted light is 7mmϕ. The detailed measurement method of the above-mentioned light beam transmittance is shown in the test example described later.

The above physical properties can be achieved by using the adhesive layer 11 of the adhesive sheet 1 as the adhesive layer. However, the present invention is not limited to these, and can also be achieved through other 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, the requirements disclosed in the above embodiments also include all design modifications and equivalents within the technical scope of the present invention.

For example, either or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted, and desired optical elements may be laminated by replacing the release sheets 12a and/or 12b.

Furthermore, the adhesive layer 11 may also be an adhesive sheet 1A as shown in FIG. 4 , in which a colorless adhesive layer 112 , a colored adhesive layer 111 , and a colorless adhesive layer 112 are sequentially laminated. Such an adhesive sheet 1A is effective when either the first display component or the second display component has unevenness on the adhesive layer 11 side.

In addition, the adhesive layer 11 may be a colorless adhesive layer 112 and a colored adhesive layer 111 laminated in two layers, or may be a colored adhesive layer 111 and a colorless adhesive layer 112 laminated in two layers. [Example]

The present invention will be further explained in detail below through examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Manufacturing Example 1] (Production of colored adhesive sheet) 1. Preparation of (meth)acrylate polymer 45 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of n-butyl acrylate, 10 parts by mass of isocamphenyl acrylate, 5 parts by mass of N-acrylylmorpholine, and 20 parts by mass of 2-hydroxyethyl acrylate , copolymerized by a solution polymerization method to prepare a (meth)acrylate polymer (A). When the molecular weight of this (meth)acrylate polymer (A) was measured by the method described below, the weight average molecular weight (Mw) was 600,000.

2. Preparation of adhesive composition 100 parts by mass of the (meth)acrylate polymer (A) obtained in the above step 1 (solid content conversion value; the same below), trimethylolpropane-modified toluene diisocyanate (Toyo) as the cross-linking agent (B) Chem Corporation, product name "BHS8515") 0.2 parts by mass, colorant (C) carbon black black pigment (C1) 0.6 parts by mass, active energy ray curable component (D) ε-caprolactone modified -(2-Acrylooxyethyl)isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-9300-1CL") 5.0 parts by mass, photopolymerization initiator (E) of 2, Mix 0.5 parts by mass of 4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 0.3 parts by mass of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, stir thoroughly, and Dilute with methyl ethyl ketone to obtain a coating solution of the adhesive composition.

Here, Table 1 shows each preparation (solid content conversion value) of the adhesive composition when the (meth)acrylate polymer (A) is 100 parts by mass (solid content conversion value). Moreover, the details of the symbols etc. described in Table 1 are as follows. [(Meth)acrylate polymer (A)] 2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate MMA: methyl methacrylate IBXA: Isobornyl acrylate ACMO: N-Acrylylmorpholine AA: acrylic HEA: 2-hydroxyethyl acrylate [Coloring agent (C)] C1～C2: Carbon black-like black pigments with the physical properties shown in Table 2

For a liquid containing a colorant of C1 to C2 diluted 10,000 times with ethyl acetate, a haze agent (manufactured by Nippon Denshoku Industry Co., Ltd., product name "SH-7000", optical path length 10mm) was used to measure the haze according to JIS K7136:2000. Degree value (%). 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 (%) of 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 standard deviation of the haze value at each wavelength at a 5 nm interval in the wavelength range of 380 nm to 780 nm. Each result is shown in Table 2.

3. Manufacturing of colored adhesive sheets Coat the coating solution of the adhesive composition obtained in the above step 2 with a knife coater on a heavy-peel release sheet that has been peeled off with a silicone release agent on one side of the polyethylene terephthalate film ( After peeling off the treated surface of Lintec Corporation, product name "SP-PET752150"), it was heated at 90°C for 1 minute to form a coating layer (thickness: 50 μm).

Thereafter, the coating layer on the heavy-peel release sheet obtained above and one side of the polyethylene terephthalate film were peeled with a silicone-based release agent to produce a light-peel release sheet (product name: Lintec Corporation) "SP-PET381031"), the release-treated surface of the light-release release sheet is in contact with the coating layer and laminated to produce a heavy-release release sheet/colored adhesive layer (a) (thickness: 50 μm)/light release A colored adhesive sheet formed by a peel-off sheet structure.

In addition, the thickness of the above-mentioned colored adhesive layer is a value measured using a constant pressure thickness gauge (manufactured by Teclock Co., Ltd., product name "PG-02") in accordance with JIS K7130 (the same applies below).

[Manufacturing Examples 2 to 5] (Preparation of colored adhesive sheets) In addition to changing the types and proportions of each monomer constituting the (meth)acrylate polymer (A), the weight average molecular weight (Mw) of the (meth)acrylate polymer (A), the cross-linking agent ( In addition to the blending amount of B), the type and blending amount of the colorant (C), the blending amount of the active energy ray curing component (D), the blending amount of the photopolymerization initiator (E), and the blending amount of the silane coupling agent , the rest is the same as in Example 1, and a colored adhesive layer (b) (Manufacturing Example 2), a colored adhesive layer (c) (Manufacturing Example 3), a colored adhesive layer (d) (Manufacturing Example 4), and a colored Colored adhesive sheet of adhesive layer (e) (Production Example 5).

In addition, the colored adhesive layer (b) produced in Production Example 2 is formed of an active energy ray non-curable adhesive, and the other colored adhesive layers (a), (c) to (e) are formed of an active energy ray non-curable adhesive. It is formed from energy ray-hardening adhesive.

[Manufacturing Examples 6-7] (Production of colorless adhesive sheet) In addition to changing the types and proportions of each monomer constituting the (meth)acrylate polymer (A), the weight average molecular weight (Mw) of the (meth)acrylate polymer (A), and the cross-linking agent (Mw) as shown in Table 1 The blending amount of B), the blending amount of colorant (C) (not blended), the blending amount of active energy ray curing component (D), the blending amount of photopolymerization initiator (E), and the blending amount of silane coupling agent Except for the quantity, the same procedure as in Example 1 was used to prepare a colorless adhesive sheet having a colorless adhesive layer (f) (Production Example 6) and a colorless adhesive layer (g) (Production Example 7).

The colorless adhesive layer (f) produced in Production Example 6 is formed of an active energy ray-curable adhesive, and the colorless adhesive layer (g) produced in Production Example 7 is formed of an active energy ray-non-hardening adhesive. formed.

The weight average molecular weight (Mw) mentioned above is a weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement). ＜Measurement conditions＞ ． GPC measuring device: Made by Tosoh Corporation, HLC-8020 ． GPC column (pass in the following order): Made by Tosoh Co., Ltd. TSK guard column HXL－H TSK glue GMHXL (×2) TSK glue G2000HXL ． Measuring solvent: tetrahydrofuran ． Measuring temperature: 40℃

[Example 1] The light release type release sheet was peeled off from the colored adhesive sheet produced in Production Example 1 to expose the colored adhesive layer (a). From the two colorless adhesive sheets prepared in Production Example 6, the light-peelable release sheets were respectively peeled off to expose the first and second colorless adhesive layers (f). The first colorless adhesive layer (f) is laminated on the exposed colored adhesive layer (a), and the heavy-release release sheet is peeled off from the first colorless adhesive layer (f), so that the first colorless adhesive layer (f) exposed. The exposed first colorless adhesive layer (f) is laminated with a second colorless adhesive layer (f). Thereafter, it was hardened for 7 days under the conditions of 23° C. and 50% RH.

In this way, a heavy-peel release sheet/colored adhesive layer (a) (1st layer; 50 μm)/colorless adhesive layer (f) (2nd layer; 50 μm)/colorless adhesive layer (f) (3rd layer) is produced. Layer; 50μm)/Adhesive sheet formed of heavy-peel type release sheet. In addition, the first layer is adhered to a planar adherend, and the third layer is adhered to an uneven adherend.

[Examples 2 to 9, Comparative Examples 1 to 3] Except that the adhesive layers of the first, second and third layers are changed as shown in Table 4, the rest is the same as in Example 1 to produce an adhesive sheet. In addition, only Example 8 has an adhesive layer formed of the first layer and the second layer.

[Test Example 1] (Measurement of gel fraction) The adhesive sheet produced in each production example was cut into a size of 80 mm × 80 mm. The adhesive layer was wrapped in a polyester mesh (mesh size 200). The mass was weighed on a precision balance and the individual weight of the mesh was subtracted. Mass, the mass of only the adhesive is calculated. The mass at this time is M1.

After that, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23°C) for 24 hours. Then take out the adhesive, air-dry it for 24 hours at a temperature of 23°C and a relative humidity of 50%, and then dry it in an oven at 80°C for 12 hours. After drying, its mass is measured on a precision balance, and the mass of the adhesive alone is calculated by subtracting the individual mass of the above-mentioned net. The mass at this time is M2. The gel fraction (%) is expressed as (M2/M1) × 100. The gel fraction of the adhesive (before UV) is therefore derived. The results are shown in Table 3.

The adhesive layer of the adhesive sheet produced in Production Examples 1 and 3 to 6 was passed through the light peeling type release sheet and irradiated with active energy rays (ultraviolet; UV) under the following conditions to harden the adhesive layer and become a hardened adhesive layer. . The gel fraction of the adhesive layer after hardening is derived as above (after UV). The results are shown in Table 3.

＜Active energy ray irradiation conditions＞． Use high-pressure mercury lamp. Illumination 200mW/cm ² , light quantity 2000mJ/cm ² . UV illumination. The light meter uses "UVPF-A1" manufactured by Eye Graphics.

[Test Example 2] (Measurement of storage modulus) The release sheet was peeled off from the adhesive sheet produced in each production example, and a plurality of layers were laminated so that the thickness of the adhesive layer became 3 mm. From the obtained laminate of adhesive layers, a cylinder with a diameter of 8 mm (height 3 mm) was punched, and these were used as samples.

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

For the adhesive sheets produced in Production Examples 1 and 3 to 6, the same sample as above was irradiated with active energy rays (ultraviolet; UV) under the same conditions as Test Example 1 to harden the adhesive layer and obtain the results after irradiation with active energy rays. sample. For the obtained sample after irradiation with active energy rays, the storage modulus at 23°C (after UV; MPa) was measured in the same manner as the sample before irradiation with active energy rays. The results are shown in Table 3.

[Test Example 3] (Measurement of total light transmittance) The adhesive layer of the adhesive sheet produced in each production example was bonded to glass, and these were used as measurement samples. In addition to the background measurement using glass, the total light transmittance (%) of the above-mentioned measurement samples was measured using a haze meter (manufactured by Nippon Denshoku Industrial Co., Ltd., product name "SH-7000") in accordance with JIS K7361-1:1997. . The results are shown in Table 3.

The surface of the third layer side of the adhesive sheet produced in Examples and Comparative Examples was bonded to glass, and the total light transmittance (%) was measured in the same manner as 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 Test Example 1 to harden the adhesive layer, and then the above measurements were performed. The results are shown in Table 5.

[Test Example 4] (Measurement of haze value) The haze value (%) of the adhesive layer of the adhesive sheet produced in each production example was measured using a haze meter (manufactured by Nippon Denshoku Industry Co., Ltd., product name "SH-7000") in accordance with JIS K7136:2000. The results are shown in Table 3.

The haze value (%) of the adhesive layer of the adhesive sheet produced in Examples and Comparative Examples was measured in the same manner as 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 Test Example 1 to harden the adhesive layer, and then the above measurements were performed. The results are shown in Table 5.

[Test example 5] (Measurement of adhesive force) From the adhesive sheet prepared in each production example, the light release type release sheet was peeled off to expose the adhesive layer and the polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "PET") with an easy-adhesion layer. A4300", thickness: 100μm) easy-adhesive layer is bonded to obtain a laminate of release sheet/adhesive layer/PET film. The obtained laminated body was cut into pieces with a width of 25 mm and a length of 100 mm, and these were used as samples.

The heavy-peel release sheet was peeled off from the above sample under conditions of 23°C and 50% RH, and the exposed adhesive layer was attached to soda-lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), and then placed in an autoclave made by Kurihara Seisakusho Co., Ltd. Pressurize at 0.5MPa and 50℃ for 20 minutes. After that, after leaving it for 24 hours under the conditions of 23°C and 50% RH, the adhesion force was measured using a tensile testing machine (manufactured by Orientec, product name "Tensilon") at a peeling speed of 300mm/min and a peeling angle of 180 degrees. (Before UV; N/25mm). For conditions other than those stated here, measurements shall be made in accordance with JIS Z0237:2009. The results are shown in Table 3.

On the other hand, a PET film was laminated on the surface on the first layer side of the adhesive layer of the adhesive sheets produced in Examples and Comparative Examples, and soda-lime glass was bonded on the surface on the third layer side. The adhesion was measured in the same manner as above. Force (before UV; N/25mm). The results are shown in Table 5.

For the adhesive sheets produced in Production Examples 1 and 3 to 6, the adhesive layer was attached to soda-lime glass in the same manner as above, treated in an autoclave, and left for 24 hours at 23°C and 50% RH. Through the PET film, active energy rays were irradiated under the same conditions as in Test Example 1 to harden the adhesive layer. For the hardened adhesive layer, measure the adhesive force (after UV; N/25mm) in the same manner as above. The results are shown in Table 3.

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 on the first layer side of the adhesive layer, and the PET film was laminated on the surface on the third layer side. After attaching the soda-lime glass, measure the adhesion after active energy ray irradiation (after UV; N/25mm) in the same manner as above. The results are shown in Table 5.

[Test Example 6] (Measurement of concave and convex following rate) On the surface of a glass plate (manufactured by NSG Precision, product name "Corning glass Eagle XG", 90 mm long 90mm × 50mm in width, 5mm in width) screen printing UV curable ink (manufactured by Imperial Ink Co., Ltd., product name "POS-911 ink"). After that, ultraviolet rays (80W/cm ² , 2 metal halide lamps, lamp height 15cm, belt rotation speed 10-15m/min) are irradiated to harden the above-mentioned ultraviolet curable ink after printing, and produce a product with high and low plane differences caused by printing. (The height of the level difference: any one of 5μm, 10μm, 15μm, 20μm and 25μm) A glass plate with a difference in level.

From the adhesive sheet prepared in each production example, the light release type release sheet was peeled off to expose the adhesive layer and the polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "PET") with an easy-adhesion layer. A4300", thickness: 100μm) easy-adhesive layer lamination. Thereafter, the heavy-peel release sheet is peeled off to expose the adhesive layer. Next, using a laminator (manufactured by FUJIPLA, product name "LPD3214"), the above-mentioned laminate was laminated on each glass plate with a difference in level, so that the adhesive layer covered the entire frame-shaped printing surface, and this was used as Samples for evaluation.

The obtained evaluation sample was autoclaved under conditions of 50° C. and 0.5 MPa for 30 minutes, and then left at normal pressure, 23° C., and 50% RH for 24 hours. The adhesive sheets produced in Production Examples 1 and 3 to 6 were irradiated with active energy rays through the PET film under the same conditions as Test Example 1 to harden the adhesive layer.

After that, it was stored under high-temperature and high-humidity conditions of 85° C. and 85% RH for 72 hours (durability test), and then the unevenness following properties were evaluated. Concave-convex followability is evaluated based on whether the printed height difference is completely buried in the adhesive layer. If bubbles, floating, peeling, etc. are observed at the interface between the printed height difference and the adhesive layer, it is judged as unable to follow. The concave and convex plane difference of printing. Here, the unevenness following property is evaluated by the unevenness following rate (%) shown by the following formula. The results are shown in Table 3. Concave and convex following rate (%) = {(After the durability test, the height of the level difference in the embedded state without bubbles, floating, peeling, etc. (μm) / (Thickness of the adhesive layer)} × 100

[Test Example 7] (Evaluation of foaming resistance) From the adhesive sheets produced in Examples and Comparative Examples, a double-release type release sheet was peeled off, and the surface on the third layer side of the exposed adhesive layer was attached to a plastic board in which a PMMA layer was laminated on a PC board (Mitsubishi Gas Chemical) Made by the company, product name "Iupilon.Sheet MR58U", thickness: 0.7mm, containing ultraviolet absorber), a plastic board with an adhesive layer is obtained on one side of the PC board.

From the plastic plate with the adhesive layer obtained above, another double-peel-type peeling sheet was peeled off, and the surface of the first layer side of the exposed adhesive layer was attached to a 70 mm × 150 mm soda-lime glass plate (Nippon Glass Glass) Made by the company, thickness: 0.7mm). Thereafter, it was treated in an autoclave under conditions of 50° C. and 0.5 MPa for 20 minutes, and then left to stand 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, pass through the plastic plate and irradiate the above adhesive layer with active energy rays under the same conditions as Test Example 1 to harden the adhesive layer. . In this way, a structure (70 mm × 150 mm) in which the plastic plate and the glass plate are bonded through the adhesive layer is obtained.

The above structure was stored under high temperature and high humidity conditions of 85° C. and 85% RH for 72 hours. Afterwards, the state of the interface between the hardened adhesive layer and the adherend (plastic plate, glass plate) is visually confirmed, and the blistering resistance is evaluated based on the following criteria. The results are shown in Table 5. ◎: No bubbles, floating or peeling. ○: There is no floating or peeling, and bubbles are slightly generated, but the level is no problem. ×: Floating and peeling occurred.

[Test Example 8] (Measurement of beam transmittance) As shown in FIG. 5 , an adhesive is used to affix polyethylene as the convex portion 52 to the center of the upper surface of a soda-lime glass plate (manufactured by Nippon Glass Glass Co., Ltd., 70 mm long × 70 mm wide × 1.1 mm thick) as the substrate 51 . An ethylene terephthalate (PET) film (manufactured by Unitika, product name "Emblet", 10 mm long × 10 mm wide × 12 μm thick) was used as the adherend 5.

From the adhesive sheets produced in Examples and Comparative Examples, a double-release type release sheet was peeled off to expose the surface of the third layer side of the adhesive layer. Thereafter, as shown in FIG. 6 , the exposed third layer side surface of the adhesive layer 11 is adhered to the side surface where the convex portion 52 of the adherend 5 is present. Thereafter, it was treated in an autoclave under conditions of 50° C. and 0.5 MPa for 20 minutes, and then left to stand at normal pressure, 23° C., and 50% RH for 24 hours. Finally, another heavy release type release sheet was peeled off from the adhesive layer 11, and this was used as a sample.

For the flat part of the above-mentioned sample, specifically the position 15 to 25 mm from the edge of the convex part 52, use an additional device for small diameter measurement (manufactured by Nippon Denshoku Co., Ltd.) to penetrate the light of a 7 mmϕ beam, in accordance with JIS K7361- 1:1997, measuring beam transmittance (%) of flat areas. The beam transmittance of this flat area is measured at 5 points, and the average value is used as the beam transmittance (%) of the flat area. An example of the light beam at the flat portion is represented by L1 in Fig. 5 .

For the parts near the concavities and convexities of the above-mentioned sample, specifically the position within 10 mm from the edge of the convex part 52 (in the dotted line frame in Figure 5), a light beam of 7mmϕ is transmitted through the same as above, and the beam transmittance (%) of the parts near the concavities and convexities is measured. ). The beam transmittance of the area near the unevenness was measured at 5 points, and the average value was used as the beam transmittance (%) of the area near the unevenness. An example of the light beam in the vicinity of the concavity and convexity is represented by L2 in FIG. 5 .

The difference (point) is calculated by subtracting the beam transmittance of the concave and convex areas from the obtained beam transmittance of the flat area. The ratio of the beam transmittance in the vicinity of the bumps to the beam transmittance in the flat spots was calculated (beam transmittance in the vicinity of the bumps/beam transmittance in the flat spots). The respective results are shown in Table 5.

[Test Example 9] (Evaluation of uneven light penetration) The sample produced in Test Example 8 was mounted on a tablet terminal (manufactured by Apple, product name "iPad (registered trademark)", resolution: 264ppi) with the substrate side facing down. For this sample, visually determine whether there is any unevenness in light penetration, and evaluate the unevenness of light penetration based on the following criteria. The results are shown in Table 5. ◎: There is no unevenness at all when light penetrates. ○: There is slight unevenness in light penetration, but it is no problem. ×: There is uneven light penetration.

[Test Example 10] (Evaluation of concealment) The adhesive sheets produced in the Examples and Comparative Examples were cut into a length of 70 mm x a width of 70 mm, and the adhesive layer of the adhesive sheet was sandwiched between two pieces of soda-lime glass (manufactured by Nippon Sheet Glass Co., Ltd., a length of 70 mm x a width of 70 mm x a thickness of 1.1 mm). Intermittent and fitting. The adhesive sheets produced in Examples 1, 3 to 5, 7 to 9 and Comparative Examples 1 to 3 were passed through a soda-lime glass plate and irradiated with active energy rays under the same conditions as in Test Example 1 to harden the adhesive layer. These are used as samples for this test example.

The black background 1 (L*: 29.8, a*: -0.7, b*: 0.6) and the black background 2 (L*: 39.2, a*: -0.4, b*: 0.4) are printed separately. on paper. Thereafter, the black background 2 is arranged on the black background 1 in a staggered and overlapping manner to form a boundary between the black background 1 and the black background 2 .

Arrange the above-mentioned sample on the background including the above-mentioned boundary part. Next, at a position 50cm away from the sample, visually determine whether the boundary area is hidden (the boundary area cannot be visually recognized but has a sense of integrity) under a 3-wavelength fluorescent lamp (distance from fluorescent lamp: 200cm), and evaluate based on the following criteria Concealment. The results are shown in Table 5. ◎: The border area is very hidden. ○: The boundary part is hidden to some extent. ×: The boundary part is clearly not hidden.

The above-mentioned black background 1 and 2 hues (based on L*a*b* specified in the CIE1976 L*a*b* color system) were obtained using a spectrophotometer (manufactured by BYK Corporation, product name "Spectro-Guide") measured.

[Test Example 11] (Evaluation of visibility) On a 15.6-inch monitor with a resolution of 1366×768 (manufactured by Fujitsu, product name "LITEBOOK A574/H"), text with a white background and black letters (font: MS PGothic) is displayed at 100% from 5 o'clock to 20 o'clock. size (1 o'clock scale).

A sample produced in the same manner as in Test Example 10 was placed on the above-mentioned display. Thereafter, the text size that can be visually recognized was confirmed at a position 50 cm away from the display, and the visibility was evaluated based on the following criteria. The results are shown in Table 3. ◎: The 6-point text can be visually recognized. ○: Characters at 6 o'clock cannot be read at all, but characters at 8 o'clock can be read. △: The 8-point character cannot be read at all, but the 15-point character can be read. ×: The 15-point text cannot be read.

[Table 1] (Meth)acrylate polymer (A) Cross-linking agent (B) Colorant(C) Active energy ray hardening ingredient (D) Photopolymerization initiator (E) Silane coupling agent Adhesive layer thickness composition Mw 2EHA BA MMA IBXA ACMO AA HEA parts by mass Kind parts by mass parts by mass parts by mass parts by mass μm Manufacturing example 1 Colored adhesive layer (a) 45 20 - 10 5 - 20 600,000 0.2 C1 0.6 5 0.5 0.3 50 Manufacturing example 2 Colored adhesive layer (b) 60 5 20 - - 5 10 500,000 0.3 C1 0.4 - - - 50 Manufacturing example 3 Colored adhesive layer (c) 45 20 - 10 5 - 20 600,000 0.2 C1 0.3 5 0.5 0.3 50 Manufacturing example 4 Colored adhesive layer (d) 45 20 - 10 5 - 20 600,000 0.2 C2 1.2 5 0.5 0.3 50 Manufacturing example 5 Colored adhesive layer (e) 45 20 - 10 5 - 20 600,000 0.2 C1 0.2 5 0.5 0.3 50 Manufacturing example 6 Colorless adhesive layer (f) 45 20 - 10 5 - 20 600,000 0.2 - - 5 0.5 0.3 50 Manufacturing example 7 Colorless adhesive layer (g) 60 5 20 - - 5 10 500,000 0.3 - - - - - 50

[Table 2] Colorant type 380nm haze value (%) 780nm haze value (%) Haze value difference (points) Average haze (%) Standard deviation of haze value C1 10.1 2.3 7.8 4.11 1.49 C2 25.0 23.7 1.3 24.89 0.48

[table 3] Gel fraction [%] Storage modulus [MPa] total light transmittance Haze value Adhesion[N/25mm] Bump following rate Before UV After UV Before UV After UV % % Before UV After UV % Manufacturing example 1 Colored adhesive layer (a) 54 71 0.06 0.16 50.2 2.9 43 46 40 Manufacturing example 2 Colored adhesive layer (b) 68 - 0.08 - 49.1 2.3 twenty two - 30 Manufacturing example 3 Colored adhesive layer (c) 52 72 0.06 0.14 71.2 2.1 42 44 40 Manufacturing example 4 Colored adhesive layer (d) 50 73 0.07 0.16 49.1 30.2 45 43 40 Manufacturing example 5 Colored adhesive layer (e) 56 71 0.05 0.13 80.2 1.7 40 45 40 Manufacturing example 6 Colorless adhesive layer (f) 52 69 0.05 0.12 ≧99 0.2 43 45 40 Manufacturing example 7 Colorless adhesive layer (g) 69 - 0.08 - ≧99 0.2 20 - 30

[Table 4] adhesive layer Tier 1 Tier 2 Level 3 Example 1 Colored adhesive layer (a) Colorless adhesive layer (f) Colorless adhesive layer (f) Example 2 Colored adhesive layer (b) Colorless adhesive layer (g) Colorless adhesive layer (g) Example 3 Colored adhesive layer (b) Colorless adhesive layer (f) Colorless adhesive layer (f) Example 4 Colored adhesive layer (c) Colorless adhesive layer (f) Colorless adhesive layer (f) Example 5 Colorless adhesive layer (f) Colored adhesive layer (a) Colorless adhesive layer (f) Example 6 Colorless adhesive layer (g) Colored adhesive layer (b) Colorless adhesive layer (g) Example 7 Colorless adhesive layer (f) Colored adhesive layer (c) Colorless adhesive layer (f) Example 8 Colored adhesive layer (a) Colorless adhesive layer (f) - Example 9 Colored adhesive layer (d) Colorless adhesive layer (f) Colorless adhesive layer (f) Comparative example 1 Colorless adhesive layer (f) Colorless adhesive layer (f) Colorless adhesive layer (f) Comparative example 2 Colored adhesive layer (e) Colored adhesive layer (e) Colored adhesive layer (e) Comparative example 3 Colorless adhesive layer (f) Colorless adhesive layer (f) Colored adhesive layer (a)

[table 5] Total light transmittance (after UV) Haze value (after UV) Adhesion[N/25mm] Blistering Resistance Assessment Beam transmittance Assessment of uneven light penetration Concealment Assessment visibility assessment Areas near bumps and bumps Flat area Flat part - difference [point] of the part near the concave and convex parts Ratio of areas near bumps to flat areas % % Before UV After UV % % Example 1 48.8 3.2 46 48 ◎ 48.23 48.71 0.48 0.990 ◎ ◎ ◎ Example 2 47.2 2.5 27 - ○ 46.68 47.12 0.44 0.991 ◎ ◎ ◎ Example 3 47.5 2.8 49 51 ◎ 47.01 47.30 0.29 0.994 ◎ ◎ ◎ Example 4 70.2 2.4 47 49 ◎ 69.81 70.05 0.24 0.997 ◎ ○ ◎ Example 5 48.8 3.2 47 48 ◎ 47.68 48.51 0.83 0.983 ○ ◎ ◎ Example 6 47.3 2.8 25 - ○ 46.40 47.12 0.72 0.985 ○ ◎ ◎ Example 7 70.1 2.6 46 48 ◎ 69.39 69.98 0.59 0.992 ○ ○ ◎ Example 8 48.9 3.0 44 48 ◎ 48.06 48.82 0.76 0.984 ○ ◎ ◎ Example 9 48.0 30.6 48 47 ◎ 47.37 47.83 0.46 0.990 ◎ ◎ ○ Comparative example 1 ≧99 0.3 45 48 ◎ 98.68 98.70 0.02 1.000 ◎ × ◎ Comparative example 2 50.4 3.6 42 44 ◎ 49.26 50.41 1.15 0.977 × ◎ ◎ Comparative example 3 48.8 3.1 43 46 ◎ 46.88 48.82 1.94 0.960 × ◎ ◎

As can be seen from Table 5, the adhesive sheet obtained in the Example has suppressed uneven transmittance and has excellent concealment and visibility. In addition, it can be seen from Table 3 and Table 5 that the adhesive sheet obtained in the Example has excellent unevenness following properties and blistering resistance. [Industrial applicability]

The adhesive sheet of the present invention can be suitably used, for example, in laminating a display component having unevenness and a desired display component in a display having a black frame material.

1,1A: Adhesive sheet 11: Adhesive layer 111: Colored adhesive layer 112: Colorless adhesive layer 12a,12b: Peel-off sheet 21: Components of the first display body 22: Components of the second display body 23: Printing layer 30:Backlight 31:Substrate 32: Luminous body 41: Diffusion element 42:LCD panel 5: Adhered body 51:Substrate 52:convex part L1: Beam in flat area L2: Beam near the concave and convex parts

[Fig. 1] is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention. [Fig. 2] is a cross-sectional view of a display body according to an embodiment of the present invention. [Fig. 3] 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 an adhesive sheet according to another embodiment of the present invention. [Figure 5] is a plan view of the adherend used in the test example (beam transmittance measurement). [Figure 6] is a cross-sectional view of a sample produced to show a test example (beam transmittance measurement).

1: Adhesive sheet

11: Adhesive layer

111: Colored adhesive layer

112: Colorless adhesive layer

12a,12b: Peel-off sheet

Claims (10)

An adhesive sheet having an adhesive layer attached to an adherend having an uneven surface, characterized in that the adhesive layer is at least one colored adhesive layer and at least one colorless adhesive layer. A laminate of agent layers, the colorless adhesive layer is located on the uneven surface of the adherend in contact with the adhesive layer, and the total light transmittance of the adhesive layer is above 3%. The adhesive sheet as described in claim 1, wherein the thickness of the colorless adhesive layer located on the surface contacting the uneven surface of the adherend is greater than the depth or height of the uneven surface of the adherend. The adhesive sheet as claimed in claim 1, wherein the adhesive layer is an adhesive layer used to bond one display component and other display components. The adhesive sheet as set forth in claim 1, wherein the adhesive constituting the colorless adhesive layer has a storage modulus at 23°C of 0.01 MPa or more and 1 MPa or less. The adhesive sheet according to claim 1, wherein the storage modulus of the adhesive constituting the colored adhesive layer at 23°C is 0.01 MPa or more and 1 MPa or less. The adhesive sheet described in Claim 1 has two release sheets, and the adhesive layer is in contact with the release surfaces of the two release sheets and is sandwiched between the release sheets. A display body, which has one display body component, other display body component components, and an adhesive layer that adheres the one display body component component and the other display body component components to each other, It is characterized in that at least one of the display component and the other display component has concavities and convexities on the side surface bonded via the adhesive layer, and the adhesive layer is as set forth in claim 1. The adhesive layer of the adhesive sheet. A display body, which has one display body component, other display body component components, and an adhesive layer that allows the one display body component component and the other display body component components to adhere to each other, characterized in that the display body component At least one of the body constituent elements and the other display body constituent elements has an uneven surface on the side bonded via the adhesive layer, and the adhesive layer has at least one colored adhesive layer, and the adhesive layer has an uneven surface. The total light transmittance is 3% or more, and the ratio of the beam transmittance in the vicinity of the unevenness to the beam transmittance in the flat area is 0.980 or more. The display body according to claim 7 or 8, wherein the unevenness is caused by a printing layer disposed on a part of the viewing plane of the display body. The display as claimed in claim 7 or 8, wherein the unevenness is caused by a plurality of luminous bodies arranged on the substrate.

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