TWI866963B - Display and adhesive sheet - Google Patents

Abstract

[Topic] To provide a display with improved design, and an adhesive sheet capable of improving the design of a display. [Solution] A display 2 having a display portion and a non-display portion, and at least one display component 21, other display components 22, and an adhesive layer 11 for bonding the one display component 21 and the other display component 22, wherein the adhesive layer 11 in the display portion has a total light transmittance of 3% or more, and according to the CIE1976 L*a*b* color system, when the lightness L* of the display portion is L*2, the chromaticity a* of the display portion is a*2, the chromaticity b* of the display portion is b*2, the lightness L* of the non-display portion is L*3, the chromaticity a* of the non-display portion is a*3, and the chromaticity b* of the non-display portion is b*3, the color difference ΔE calculated by the following formula (I) is less than 2.00.

Description

Display and adhesive sheet

The present invention relates to a display suitable for use in a vehicle or the like and an adhesive sheet used for the display.

In recent years, many display devices (displays) such as car mounting panels, car navigation systems, various instruments installed on dashboards, tablet terminals for general users, tablet terminals or digital signage for business use, and digital signage for outdoor use use image display devices such as liquid crystal display devices or organic light-emitting diode devices.

In displays such as those used in vehicles, it is required that when the light of the display is turned off, the display portion and the non-display portion of the display, such as peripheral components such as frame materials, be coordinated in appearance and the design is improved. For this reason, it is considered to color the display, and inventions related to coloring of the display are disclosed in patent documents 1 to 4, for example. [Prior art document] [Patent document]

[Patent Document 1] Japanese Patent Publication No. 2000-313871 [Patent Document 2] Japanese Patent Publication No. 2009-188298 [Patent Document 3] Japanese Patent Publication No. 2012-234028 [Patent Document 4] Japanese Patent Publication No. 2017-57375

[Identify the problem you want to solve]

However, the technologies disclosed in the above-mentioned patent documents 1 to 4 have different purposes of coloring, and therefore cannot coordinate the appearance of the display part and the non-display part when the display light is turned off, thereby improving the design.

The present invention is made in view of the above-mentioned actual situation, and aims to provide a display body with improved design and an adhesive sheet that can improve the design of the display body. [Means for solving the problem]

In order to achieve the above-mentioned object, first, the present invention provides a display having a display portion and a non-display portion, and at least one display component and other display components, and an adhesive layer for bonding the one display component and the other display components, wherein the total light transmittance of the adhesive layer in the display portion is 3% or more, and according to the CIE1976 L*a*b* color system, when the lightness L* of the display portion is L*2, the chromaticity a* of the display portion is a*2, the chromaticity b* of the display portion is b*2, the lightness L* of the non-display portion is L*3, the chromaticity a* of the non-display portion is a*3, and the chromaticity b* of the non-display portion is b*3, the color difference ΔE calculated by the following formula (I) is 2.00 or less (Invention 1) .

In the above invention (Invention 1), since the total light transmittance is 3% or more, the visibility of the screen and image when the display light is on can be ensured. In addition, since the color difference ΔE is as described above, the appearance coordination of the display part and the non-display part when the display light is off can be sought, thereby improving the design.

In the above invention (Invention 1), preferably, L*3 of the non-display portion is 0.1 to 50, a*3 of the non-display portion is -20 to 20, and b*3 of the non-display portion is -20 to 20 (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferred that the non-display portion is black (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferred that at least one of the above-mentioned one display component and the above-mentioned other display component has a protrusion on the surface of the above-mentioned adhesive layer side, and the above-mentioned protrusion constitutes a part or the whole of the above-mentioned non-display part (Invention 4).

Second, the present invention provides an adhesive sheet having an adhesive layer for bonding one display component and another display component of a display having a display portion and a non-display portion, wherein the adhesive layer has a total light transmittance of 3% or more, and the adhesive layer is colored so that in the display obtained by bonding the one display component and the other display component via the adhesive layer, the light transmittance according to CIE 1976 is achieved. According to the L*a*b* color system, when the lightness L* of the display portion is L*2, the chromaticity a* of the display portion is a*2, the chromaticity b* of the display portion is b*2, the lightness L* of the non-display portion is L*3, the chromaticity a* of the non-display portion is a*3, and the chromaticity b* of the non-display portion is b*3, the color difference ΔE calculated by the following formula (I) is less than 2.00 (Invention 5) .

In the above invention (Invention 5), it is preferred that, according to the CIE1976 L*a*b* colorimetric system, when the lightness L* of the adhesive layer is L*1, the chromaticity a* of the adhesive layer is a*1, and the chromaticity b* of the adhesive layer is b*1, the L*1 of the adhesive layer is 5 to 95, the a*1 of the adhesive layer is -20 to 20, and the b*1 of the adhesive layer is -20 to 20 (Invention 6).

In the above inventions (Inventions 5 and 6), it is preferred that the haze value of the adhesive layer is 0.1% or more and 80% or less (Invention 7).

In the above inventions (Inventions 5 to 7), preferably, the adhesive constituting the adhesive layer contains a colorant (Invention 8).

In the above invention (Invention 8), preferably, the coloring agent is a black pigment or dye (Invention 9).

In the above inventions (Inventions 5 to 9), it is preferred to have two peeling sheets and the adhesive layer (Invention 10) that is in contact with the peeling surfaces of the two peeling sheets and sandwiched between the peeling sheets. [Effect of the invention]

The display of the present invention has a display portion and a non-display portion that are in harmony when the light is off, and the design is improved. In addition, according to the adhesive sheet of the present invention, the design of the display can be improved.

The following is a description of an embodiment of the present invention. [Display] A display (display) in one embodiment of the present invention has a display portion and a non-display portion, and at least one display component and other display components, and an adhesive layer for bonding the one display component and the other display components.

The types of displays of this embodiment include, for example, automobile mounting panels, automobile navigation systems, various instruments installed on dashboards, etc., displays of tablet terminals for general users, displays of tablet terminals or digital signage for business, displays of digital signage for outdoor use, etc. However, the displays of the present invention are not limited to these.

Furthermore, the display device of the display body of the present embodiment may be a type of a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic light emitting diode (organic EL) display, an electronic book, or the like, and may also be a touch panel.

The display part of the display of the present embodiment refers to the part that displays the screen or image via the display device as described above. Furthermore, the non-display part of the display of the present embodiment refers to the part of the display that does not display the screen or image, for example, the part of the printed layer that forms a frame shape in the display component, or the component that is set on the periphery of the display component, the component that divides the screen, etc.

In the display of this embodiment, the total light transmittance of the adhesive layer in the display part is 3% or more. With the total light transmittance being 3% or more, the visibility of the screen and image when the display is lit can be ensured. In addition, the total light transmittance in this specification is a value measured according to JIS K7361-1:1997.

Furthermore, in the display of the present embodiment, according to the CIE1976 L*a*b* colorimetric system, when the lightness L* of the display part is L*2, the chromaticity a* of the display part is a*2, the chromaticity b* of the display part is b*2, and the lightness L* of the non-display part is L*3, the chromaticity a* of the non-display part is a*3, and the chromaticity b* of the non-display part is b*3, the color difference ΔE calculated by the following formula (I) is less than 2.00.

In the display of this embodiment, since the color difference ΔE is as described above, the appearance coordination of the display part and the non-display part when the display light is off can be sought, thereby improving the design. In addition, the measurement method of the lightness L*, chromaticity a* and chromaticity b* in this specification is shown in the test example described below.

From the perspective of the visibility of the screen and the image, the total light transmittance of the adhesive layer in the display part is 3% or more, preferably 10% or more, more preferably 25% or more, particularly preferably 40% or more, and more preferably 50% or more. The upper limit of the total light transmittance is usually 100% or less, and when considering the relationship with the above-mentioned color difference ΔE, it is preferably 98% or less, more preferably 90% or less, particularly preferably 80% or less, and more preferably 70% or less, and 57% or less is the best.

Furthermore, from the viewpoint of the appearance coordination between the display part and the non-display part, the color difference ΔE is 2.00 or less, preferably 1.80 or less, more preferably 1.50 or less, particularly preferably 1.20 or less, and when considering the visibility of the screen and the image, it is more preferably 1.00 or less, and most preferably 0.80 or less. The lower limit of the color difference ΔE is not particularly limited, and the minimum value is 0, but when considering the relationship with the total light transmittance, it is preferably 0.01 or more, particularly preferably 0.05 or more, and more preferably 0.1 or more.

Preferably, L*3 of the non-display portion is 0.1 to 50, a*3 of the non-display portion is -20 to 20, and b*3 of the non-display portion is -20 to 20. More preferably, L*3 of the non-display portion is 0.5 to 30, a*3 of the non-display portion is -10 to 10, and b*3 of the non-display portion is -10 to 10. In particular, L*3 of the non-display portion is 1.0 to 10, a*3 of the non-display portion is -5 to 5, and b*3 of the non-display portion is -5 to 5. More preferably, L*3 of the non-display portion is 2.0 to 5.0, a*3 of the non-display portion is -1 to 1, and b*3 of the non-display portion is -1 to 1. With these, the color difference ΔE mentioned above can be easily satisfied, and the non-display portion in the display body has a better color tone. It is preferred that the non-display portion is specifically black.

On the other hand, preferably, the L*2 of the display part is 0.1 to 50, the a*2 of the display part is -20 to 20, and the b*2 of the display part is -20 to 20. More preferably, the L*2 of the display part is 0.5 to 30, the a*2 of the display part is -10 to 10, and the b*2 of the display part is -10 to 10. In particular, the L*2 of the display part is 1.0 to 10, the a*2 of the display part is -5 to 5, and the b*2 of the display part is -5 to 5. More preferably, the L*2 of the display part is 2.0 to 5.0, the a*2 of the display part is -1 to 1, and the b*2 of the display part is -1 to 1. By doing so, it is easy to satisfy the above-mentioned color difference ΔE, and the display part in the display body has a better color tone when the display body light is off. Specifically, the display part is preferably black.

Furthermore, according to the CIE1976 L*a*b* color system, when the lightness L* of the adhesive layer used in the present embodiment is L*1, the chromaticity a* of the adhesive layer is a*1, and the chromaticity b* of the adhesive layer is b*1, the L*1 of the adhesive layer is 5 to 95, the a*1 of the adhesive layer is -20 to 20, and the b*1 of the adhesive layer is -2 0 to 20 is preferred, and in particular, L*1 of the adhesive layer is 8 to 93, a*1 of the adhesive layer is -10 to 10, and b*1 of the adhesive layer is -10 to 10. Furthermore, L*1 of the adhesive layer is 10 to 90, a*1 of the adhesive layer is -5 to 5, and b*1 of the adhesive layer is -5 to 5. Through these, the above-mentioned color difference ΔE and total light transmittance are easily satisfied. The above-mentioned adhesive layer is preferably colored black.

In the above formula (I), the difference (L*2-L*3) between the lightness L*2 of the display part and the lightness L*3 of the non-display part is preferably -2.00 to 2.00, but when considering the relationship between the difference (a*2-a*3) between the chromaticity a*2 of the display part and the chromaticity a*3 of the non-display part and the difference (b*2-b*3) between the chromaticity b*2 of the display part and the chromaticity b*3 of the non-display part, it is preferably -1.50 to 1.50, more preferably -1.00 to 1.00, particularly preferably -0.80 to 0.80, more preferably -0.60 to 0.60, and most preferably -0.40 to 0.40. By these, the above color difference ΔE can be easily satisfied.

In the above formula (I), the difference (a*2-a*3) between the chromaticity a*2 of the display part and the chromaticity a*3 of the non-display part is preferably -2.00 to 2.00, but when considering the relationship between the difference (L*2-L*3) between the lightness L*2 of the display part and the lightness L*3 of the non-display part and the difference (b*2-b*3) between the chromaticity b*2 of the display part and the chromaticity b*3 of the non-display part, it is preferably -1.50 to 1.50, more preferably -1.00 to 1.00, particularly preferably -0.80 to 0.80, more preferably -0.60 to 0.60, and most preferably -0.54 to 0.54. By these, the above color difference ΔE can be easily satisfied.

In the above formula (I), the difference (b*2-b*3) between the chromaticity b*2 of the display part and the chromaticity b*3 of the non-display part is preferably -2.00 to 2.00, but when considering the relationship between the difference (L*2-L*3) between the lightness L*2 of the display part and the lightness L*3 of the non-display part and the difference (a*2-a*3) between the chromaticity a*2 of the display part and the chromaticity a*3 of the non-display part, it is preferably -1.50 to 1.50, more preferably -1.00 to 1.00, particularly preferably -0.80 to 0.80, more preferably -0.50 to 0.50, and most preferably -0.25 to 0.25. By these, the above color difference ΔE can be easily satisfied.

Here, at least one of the above-mentioned display component and the other display component preferably has a convex portion on the surface of the adhesive layer-bonded side. In this case, the convex portion may also constitute a part or all of the above-mentioned non-display portion. Such a convex portion, for example, forms a printed layer in the shape of a top view frame on the adhesive layer side of the display component. An example of a display having such a convex portion is described below with reference to the drawings.

As shown in FIG1 , the display 2 of this embodiment is composed of a first display component 21 (a display component), a second display component 22 (another display component), and an adhesive layer 11 located therebetween to bond the first display component 21 and the second display component 22 to each other. In this embodiment, the first display component 21 has a printed layer 3 as an example of a convex portion on the surface on the adhesive layer 11 side. The printed layer 3 as this convex portion forms a step relative to the portion where the printed layer 3 does not exist.

The first display component 21 is preferably a protective panel composed of a laminate including a glass plate, a plastic plate, etc., in addition to the glass plate, the plastic plate, etc., and is particularly preferably a protective panel composed of a plastic plate, or a laminate including a plastic plate, etc. In this case, the printed layer 3 is generally formed in a frame shape on the side of the adhesive layer 11 in the first display component 21.

The glass plate is not particularly limited, and may be, for example, chemically strengthened glass, alkali-free glass, quartz glass, sodium calcium glass, barium-strontium glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but is generally 0.1 to 5 mm, preferably 0.2 to 2 mm.

The plastic sheet is not particularly limited, and may be, for example, a polycarbonate resin (PC) sheet, an acrylic resin sheet such as a polymethyl methacrylate resin (PMMA) sheet, or a plastic sheet in which an acrylic resin layer such as a polymethyl methacrylate resin layer is laminated on a polycarbonate resin sheet. Furthermore, the polycarbonate resin sheet may contain a resin other than polycarbonate resin as a material constituting the sheet, and the acrylic resin sheet may contain a resin other than acrylic resin as a material constituting the sheet. Furthermore, the plastic sheet may be one to which an ultraviolet light absorber is added.

The thickness of the plastic plate is not particularly limited, but is generally 0.2 to 5 mm, preferably 0.4 to 3 mm, and particularly preferably 0.6 to 2.5 mm.

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

The second display component 22 is preferably an optical element to be attached to the first display component 21, a display module (such as a liquid crystal (LCD) module, a light-emitting diode (LED) module, an organic light-emitting diode (organic EL) module, etc.), an optical element that is a part of the display module, or a laminate that includes a display module.

The optical elements include anti-scattering films, polarizing plates (polarizing films), polarizers, phase difference plates (phase difference films), viewing angle compensation films, brightness enhancement films, contrast enhancement films, liquid crystal polymer films, diffusion films, semi-transmissive reflective films, transparent conductive films, etc. The anti-scattering film is, for example, a hard coating film formed by forming a hard coating layer on one side of a substrate film.

The material constituting the printing layer 3 is not particularly limited, and known materials for printing can be used. The thickness of the printing layer 3, that is, the height of the step, preferably has a lower limit of 3 μm or more, preferably 5 μm or more, particularly preferably 7 μm or more, and more preferably 10 μm or more. When the lower limit of the height of the transparent step is as described above, the concealment of the electrical wiring, etc. from the viewer's side can be fully ensured. In addition, the upper limit of the height of the step is preferably 50 μm or less, preferably 35 μm or less, particularly preferably 25 μm or less, and more preferably 20 μm or less. When the upper limit of the height of the transparent step is as described above, the deterioration of the step followability of the printing layer 3 by the adhesive layer 11 can be prevented.

The adhesive layer 11 can be formed by the adhesive layer of the adhesive sheet described below. However, as long as the above-mentioned physical properties are satisfied, the present invention is not limited thereto.

[Adhesive sheet] An adhesive sheet in one embodiment of the present invention has an adhesive layer for bonding a display component and other components constituting a display having a display portion and a non-display portion. Preferably, a peeling sheet is laminated on one or both sides of the adhesive layer.

The adhesive layer in this embodiment is colored so that the total light transmittance is 3% or more and the color difference ΔE is 2.00 or less. The preferred ranges of the lightness L* (= L*1) of the adhesive layer, the chromaticity a* (= a*1) of the adhesive layer, and the chromaticity b* (= b*1) of the adhesive layer in this embodiment are as described above.

The specific structure of an example of the adhesive sheet of this embodiment is shown in FIG2. As shown in FIG2, the adhesive sheet 1 is composed of two peeling sheets 12a, 12b, and an adhesive layer 11 that is in contact with the peeling surfaces of the two peeling sheets 12a, 12b and sandwiched between the two peeling sheets 12a, 12b. In addition, the peeling surface of the peeling sheet in this specification refers to the surface of the peeling sheet that has peeling properties, including either a surface that has been subjected to peeling treatment or a surface that has not been subjected to peeling treatment but shows peeling properties.

1. Each component 1-1.   Adhesive layer The type of adhesive constituting the adhesive layer 11 of the adhesive sheet 1 of this embodiment is not particularly limited, and any of acrylic adhesives, polyester adhesives, polyurethane adhesives, rubber adhesives, silicone adhesives, etc. may be used. In addition, the adhesive may be any of an emulsion type, a solvent type, or a solvent-free type, and may be any of a crosslinked type or a non-crosslinked type. Among these, acrylic adhesives having excellent adhesive properties and optical properties are preferred.

Furthermore, the acrylic adhesive may be active energy ray-hardening or active energy ray-non-hardening. Furthermore, the acrylic adhesive is preferably a crosslinking type, and more preferably a thermal crosslinking type.

Specifically, the adhesive is preferably a crosslinked adhesive composition (hereinafter referred to as "adhesive composition P") containing a (meth)acrylate polymer (A), a crosslinking agent (B), and a coloring agent (C). Furthermore, when the adhesive is an active energy ray-curable adhesive, the adhesive composition P preferably further contains an active energy ray-curable component (D).

The adhesive obtained from such adhesive composition P can exhibit excellent optical properties, adhesion, durability (step-following property under high temperature and high humidity conditions, 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) Components of the adhesive composition (1-1) (Meth)acrylate polymer (A) The (meth)acrylate polymer (A) of this embodiment preferably has a monomer containing a reactive group in the molecule that reacts with a crosslinking agent (B) as a monomer unit constituting the polymer. The reactive group from the reactive group-containing monomer reacts with the crosslinking agent (B) to form a crosslinked structure (stereo-network structure), thereby obtaining an adhesive having a desired cohesive force.

Preferred examples of the reactive group-containing monomer include monomers having a hydroxyl group in the molecule (hydroxyl-containing monomers), monomers having a carboxyl group in the molecule (carboxyl-containing monomers), and monomers having an amine group in the molecule (amine-containing monomers). Among these, hydroxyl-containing monomers or carboxyl-containing monomers having excellent reactivity with the crosslinking agent (B) are preferred, and a hydroxyl-containing monomer and a carboxyl-containing monomer may be used in combination.

The hydroxyl group-containing monomers include, for example, hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Among them, hydroxyalkyl (meth)acrylates having a hydroxyalkyl group having 1 to 4 carbon atoms are preferred from the viewpoint of the reactivity of the hydroxyl group in the obtained (meth)acrylate polymer (A) with the crosslinking agent (B) and the copolymerizability with other monomers. Specifically, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred examples, and 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate are particularly preferred examples. These can be used individually or in combination of 2 or more.

Carboxyl group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and liraconic acid. Among them, acrylic acid is preferred from the viewpoint of the reactivity of the carboxyl group in the obtained (meth)acrylate polymer (A) with the crosslinking agent (B) and the copolymerizability with other monomers. These may be used alone or in combination of two or more.

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

The (meth)acrylate polymer (A) contains a monomer containing a reactive group as a monomer unit constituting the polymer, and the lower limit is preferably 1 mass % or more, particularly preferably 5 mass % or more, and more preferably 10 mass % or more. When the monomer containing a reactive group is a hydroxyl group-containing monomer, the lower limit is preferably 15 mass % or more, and more preferably 20 mass % or more. In addition, the (meth)acrylate polymer (A) contains a monomer containing a reactive group as a monomer unit constituting the polymer, and the upper limit is preferably 35 mass % or less, particularly preferably 30 mass % or less, and more preferably 25 mass % or less. When the (meth)acrylate polymer (A) contains a monomer containing a reactive group as a monomer unit in the above amount, a good cross-linking structure is formed in the obtained adhesive, and the desired cohesive force is obtained. In addition, the dispersibility of the coloring agent (C) in the adhesive tends to be good, and the obtained adhesive has good reproducibility and uniformity of the above-mentioned optical properties, and is easy to satisfy the above-mentioned color difference ΔE. Furthermore, when the monomer containing a reactive group is a hydroxyl group-containing monomer, when the content is 15% by mass or more, a predetermined amount of hydroxyl groups remain in the adhesive. Hydroxyl groups are hydrophilic groups. When such hydrophilic groups exist in the adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, the compatibility with water immersed in the adhesive under such high temperature and high humidity conditions is good, and as a result, the whitening of the adhesive when it returns to normal temperature and humidity is suppressed (excellent resistance to wet heat whitening).

Furthermore, the (meth)acrylate polymer (A) may 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 a carboxyl group-containing monomer, even if there are problems caused by the acid on the object to which the adhesive is attached, such as in the case of a transparent conductive film or metal film such as tin-doped indium oxide (ITO), such problems caused by the acid (corrosion, change in resistance value, etc.) can be suppressed. However, it is allowed to contain a predetermined amount of carboxyl group-containing monomer to the extent that such problems do not occur. Specifically, it is allowed that the (meth)acrylate polymer (A) contains a carboxyl group-containing monomer as a monomer unit in an amount of less than 0.1 mass%, preferably less than 0.01 mass%, and more preferably less than 0.001 mass%.

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 adhesion, the alkyl (meth)acrylate is preferably an alkyl (meth)acrylate having an alkyl group with a carbon number of 1 to 20. Examples of the alkyl (meth)acrylate having an alkyl group with a carbon number of 1 to 20 include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, and octadecyl (meth)acrylate. Among them, from the viewpoint of further improving the adhesiveness, (meth) alkyl acrylates having an alkyl group with 1 to 8 carbon atoms are preferred, methyl (meth) acrylate, n-butyl (meth) acrylate, or 2-ethylhexyl (meth) acrylate are particularly preferred, and methyl methacrylate, n-butyl acrylate, or 2-ethylhexyl acrylate is more preferred. These may be used alone or in combination of two or more.

The (meth)acrylate polymer (A) preferably contains 40% by mass or more of the (meth)acrylate alkyl ester as a monomer unit constituting the polymer, particularly preferably 50% by mass or more, and more preferably 60% by mass or more. When the lower limit of the content of the (meth)acrylate alkyl ester is as described above, the (meth)acrylate polymer (A) can exhibit suitable adhesion. In addition, the colorant (C) tends to have good dispersibility in the adhesive, and the (meth)acrylate polymer (A) can be prevented from losing the desired adhesion. Therefore, the obtained adhesive can exhibit suitable adhesion, and the reproducibility and uniformity of the above-mentioned optical properties are good, and the above-mentioned color difference ΔE is easily satisfied. In addition, the (meth)acrylate polymer (A) preferably contains 99% by mass or less, more preferably 95% by mass or less, particularly preferably 90% by mass or less, more preferably 85% by mass or less, and most preferably 80% by mass or less of the (meth)acrylate alkyl ester as a monomer unit constituting the polymer. When the upper limit of the content of the (meth)acrylate alkyl ester is as described above, an appropriate amount of other monomer components such as a monomer containing a reactive functional group may be introduced into the (meth)acrylate polymer (A).

The (meth)acrylate polymer (A) preferably also contains 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 presumed that the presence of the monomer in the polymer increases the distance between the polymers, and the resulting adhesive can be made excellent in flexibility. Therefore, the adhesive becomes excellent in step-following property.

The carbon ring of the alicyclic structure in the alicyclic structure-containing monomer may be a saturated structure or may partially have unsaturated bonds. Furthermore, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic or tricyclic alicyclic structure. From the viewpoint of making the distances between the obtained (meth)acrylate polymers (A) appropriate and imparting higher stress relaxation properties through the adhesive, the alicyclic structure is preferably a polycyclic alicyclic structure (polycyclic structure). Furthermore, considering the compatibility of the (meth)acrylate polymer (A) and other components, the polycyclic structure is particularly preferably bicyclic to tetracyclic. Furthermore, from the viewpoint of imparting stress relaxation as described above, the carbon number of the alicyclic structure (i.e., the total number of carbon atoms in the portion forming the ring, and when a plurality of rings exist independently, the total number of carbon atoms) is usually preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the carbon number of the alicyclic structure is not particularly limited, but from the viewpoint of compatibility as described above, it is preferably 15 or less, and particularly preferably 10 or less.

Specific examples of the above-mentioned alicyclic structure-containing monomers include cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate, isoborneol (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, etc. Among them, dicyclopentyl (meth)acrylate (carbon number of alicyclic structure: 10), adamantyl (meth)acrylate (carbon number of alicyclic structure: 10), or isoborneol (meth)acrylate (carbon number of alicyclic structure: 7) are preferred, and isoborneol (meth)acrylate is particularly preferred, and isoborneol acrylate is even more preferred. These may be used alone or in combination of two or more.

When the (meth)acrylate polymer (A) contains a lipid-containing ring structure monomer as a monomer unit constituting the polymer, it is preferred that the lipid-containing ring structure monomer be 1% by mass or more, particularly preferably 4% by mass or more, and even more preferably 8% by mass or more. Furthermore, the (meth)acrylate polymer (A) preferably contains 30% by mass or less of the lipid-containing ring structure monomer as a monomer unit constituting the polymer, particularly preferably 22% by mass or less, and even more preferably 14% by mass or less. When the content of the lipid-containing ring structure monomer is within the above range, the obtained adhesive has better step-following property and better adhesion to plastics.

Furthermore, the (meth)acrylate polymer (A) preferably also contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. By having the nitrogen atom-containing monomer as a constituent unit in the polymer, the adhesive can be given a predetermined polarity, and can also have excellent affinity for an adherend having a certain degree of polarity such as glass. From the perspective of the (meth)acrylate polymer (A) having appropriate rigidity, the nitrogen atom-containing monomer is preferably a monomer having a nitrogen-containing heterocyclic ring. Furthermore, from the perspective of increasing the degree of freedom of the nitrogen atom-containing monomer portion in the high-order structure of the constituted adhesive, the nitrogen atom-containing monomer is preferably a monomer that does not contain a reactive unsaturated double bond group other than one polymerizable group used for polymerization to form the (meth)acrylate polymer (A).

Examples of monomers having a nitrogen-containing heterocyclic ring include N-(methyl)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(methyl)acryloylpyrrolidone, N-(methyl)acryloylpiperidine, N-(methyl)acryloylpyrrolidine, N-(methyl)acryloylaziridine, aziridinylethyl(methyl)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, and N-vinylphthalimide. Among them, N-(methyl)acryloylmorpholine is preferred, and N-acryloylmorpholine is particularly preferred, as it exhibits relatively good adhesion. These may be used alone or in combination of two or more.

When the (meth)acrylate polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the content of the nitrogen atom-containing monomer is preferably 1% by mass or more, particularly preferably 4% by mass or more, and more preferably 8% by mass or more. Furthermore, the (meth)acrylate polymer (A) contains the nitrogen atom-containing monomer as a monomer unit constituting the polymer in an amount of preferably 20% by mass or less, particularly preferably 16% by mass or less, and more preferably 12% by mass or less. When the content of the nitrogen atom-containing monomer is within the above range, the obtained adhesive can fully exert excellent adhesion to glass.

The (meth)acrylate polymer (A) may contain other monomers as monomer units constituting the polymer as needed. In order not to impair the aforementioned effects of the monomer containing a reactive functional group, the other monomers are preferably monomers that do not contain a reactive functional group. Examples of such monomers include (meth)acrylate alkoxyalkyls such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, vinyl acetate, styrene, and the like. These may be used alone or in combination of two or more.

The (meth)acrylate polymer (A) is preferably a linear polymer. Since it is a linear polymer, molecular chains are easily entangled, and it is expected that the cohesive force will be improved. Therefore, the obtained adhesive is likely to exhibit an appropriate gel fraction and adhesive force, and is likely to be excellent in step-following property and blister resistance under high temperature and high humidity conditions.

In addition, the (meth)acrylate polymer (A) is preferably a solution polymer obtained by a solution polymerization method. Since it is a solution polymer, a high molecular weight polymer can be easily obtained, and it is expected that the cohesive force can be improved. Therefore, the obtained adhesive can easily exhibit a suitable gel fraction and adhesive force, and can easily become one with excellent step-following property and blister 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 weight average molecular weight of the (meth)acrylate polymer (A) preferably has a lower limit of 200,000 or more, particularly preferably 300,000 or more, more preferably 400,000 or more, and more preferably 450,000 or more from the viewpoint of the dispersibility of the colorant (C). When the lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is as described above, the values of the gel fraction and adhesion of the obtained adhesive are likely to be suitable, and the step followability and blister resistance under high temperature and high humidity conditions are better. In addition, there is a tendency that the colorant (C) can be well dispersed in the adhesive, so the obtained adhesive has good reproducibility and uniformity of the above optical properties, and is likely to satisfy the above color difference ΔE.

The upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 2 million or less, more preferably 1.5 million or less, particularly preferably 1 million or less, and more preferably 800,000 or less. From the perspective of easily developing a higher adhesive force, it is preferably 650,000 or less. When the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is as above, the values of the gel fraction of the obtained adhesive are likely to be appropriate, and the initial step followability becomes better. In addition, the weight average molecular weight in this specification is a value converted to standard polystyrene measured by gel permeation chromatography (GPC).

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

(1-2) Crosslinking agent (B) The crosslinking agent (B) can crosslink the (meth)acrylate polymer (A) by heating the adhesive composition P, thereby forming a good three-dimensional network structure. As a result, the cohesive force of the obtained adhesive is improved, and the adhesive has excellent step-following properties and blister resistance under high temperature and high humidity conditions.

The crosslinking agent (B) may be any crosslinking agent that reacts with the reactive group of the (meth)acrylate polymer (A), and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, hydrazine crosslinking agents, aldehyde crosslinking agents, oxazoline crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, and ammonium salt crosslinking agents. Among the above, when the reactive group of the (meth)acrylate polymer (A) is a hydroxyl group, an isocyanate crosslinking agent having excellent reactivity with a hydroxyl group is preferably used, and when the reactive group of the (meth)acrylate polymer (A) is a carboxyl group, an epoxy crosslinking agent having excellent reactivity with a carboxyl group is preferably used. The crosslinking agent (B) may be used alone or in combination of two or more.

Isocyanate crosslinking agents at least include polyisocyanate compounds. Polyisocyanate compounds include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, and diurea and isocyanurate forms thereof, and adducts of the reaction products of the reaction products with small molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trihydroxymethylpropane, and castor oil. Among them, trihydroxymethylpropane-modified aromatic polyisocyanates, particularly trihydroxymethylpropane-modified toluene diisocyanate and trihydroxymethylpropane-modified xylene diisocyanate are preferred from the viewpoint of reactivity with hydroxyl groups.

Epoxy crosslinking agents include, for example, 1,3-bis(N,N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl-m-xylenediamine, ethylene glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, trihydroxymethylpropane diepoxypropyl ether, diepoxypropylaniline, diepoxypropylamine, 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 crosslinking agent (B) is preferably 0.01 parts by mass or more, particularly preferably 0.03 parts by mass or more, and more preferably 0.05 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). In addition, the content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and more preferably 0.4 parts by mass or less. When the content of the crosslinking agent (B) is within the above range, the adhesive obtained can exhibit good cohesive force, and the values of gel fraction and adhesive force can easily become appropriate, and the step followability and blister resistance under high temperature and high humidity conditions are better.

(1-3) Colorant (C) The colorant (C) may be a pigment or a dye. The dye may be an inorganic pigment or an organic pigment. In view of the durability of the obtained adhesive, inorganic pigments are preferred. The color of the colorant is selected so that the color difference ΔE is within the above range. Generally, dark or dark colors such as black, brown, dark blue, purple, blue, etc. are preferred, and black is particularly preferred.

Inorganic pigments, such as carbon black, 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.

嗪(dioxazine)類色素、喹吖啶酮(quinacridone)類色素、異吲哚啉酮(isoindolinone)類色素、喹啉黃(quinophthalone)類色素、吡咯(pyrrole)類色素、硫靛(thioindigo)類色素、金屬錯合物類色素(金屬錯合物鹽染料)、二硫醇金屬錯合物類色素、靛酚(indophenol)類色素、三芳基甲烷類色素、蒽醌(anthraquinone)類色素、二

嗪(dioxazine)類色素、萘酚(naphthol)類色素、甲亞胺(azomethine)類色素、苯并咪唑酮(benzimidazolone)類色素、皮蒽酮(pyranthrone)類色素及還原類(threne)色素等。 In addition, organic pigments and organic dyes include, for example, aminium pigments, cyanine pigments, merocyanine pigments, croconium pigments, squarylium pigments, azulenium pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, phthalocyanine pigments, naphthalocyanine pigments, naphtholactam pigments, azo pigments, condensed azo pigments, indigo pigments, perinone pigments, perylene pigments, dimethine pigments,

dioxazine pigments, quinacridone pigments, isoindolinone pigments, quinophthalone pigments, pyrrole pigments, thioindigo pigments, metal complex pigments (metal complex salt dyes), dithiol metal complex pigments, indophenol pigments, triarylmethane pigments, anthraquinone pigments, dithiocarboxylic acid pigments,

dioxazine pigments, naphthol pigments, azomethine pigments, benzimidazolone pigments, pyranthrone pigments and threne pigments.

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

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

From the perspective of color difference △E, carbon black, nigrosine-based black dyes, and chromate-based black dyes are preferred among the above-mentioned coloring agents. In addition, the surface of carbon black may be subjected to a predetermined treatment (e.g., solvation treatment) or may not be subjected to such treatment.

The above-mentioned colorant, the liquid of the colorant diluted 10,000 times with ethyl acetate, has an average haze value of the average haze value at a wavelength of 780nm and the haze value at a wavelength of 380nm, and the lower limit is preferably 1% or more, 2% or more is particularly preferred, and 3% or more is more preferred. In addition, the upper limit of the average haze value of the above-mentioned colorant is preferably 60% or less, 40% or less is preferred, 30% or less is particularly preferred, 20% or less is more preferred, and 10% or less is the best. By using such a colorant in an appropriate amount, the obtained adhesive becomes one with good reproducibility and uniformity of the above-mentioned optical properties, and the above-mentioned color difference △E can be easily satisfied.

In addition, the colorant is diluted 10,000 times with ethyl acetate, and the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm is preferably 30 points or less, more preferably 25 points or less, particularly preferably 20 points or less, more preferably 16 points or less, and most preferably 10 points or less. By using such a colorant in an appropriate amount, the obtained adhesive has good reproducibility and uniformity of the above optical properties, and the above color difference ΔE can be easily satisfied.

The lower limit of the difference in haze value may be 0 points, but from the viewpoint of easily adjusting the optical properties of the adhesive layer 11 to be appropriate, 0.1 points or more is preferred, 0.5 points or more is more preferred, 1 point or more is particularly preferred, and 3 points or more is even more preferred.

The haze value of the liquid of the above-mentioned coloring agent diluted 10,000 times with ethyl acetate at a wavelength of 780nm is preferably 0.1-50%, preferably 0.5-40%, particularly preferably 1-30%, more preferably 1.5-20%, and most preferably 2-10%. In addition, the haze value of the liquid of the above-mentioned coloring agent diluted 10,000 times with ethyl acetate at a wavelength of 380nm is preferably 1-60%, preferably 3-50%, particularly preferably 6-40%, more preferably 8-30%, and most preferably 10-20%. Therefore, it is easy to meet the above-mentioned haze value difference.

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 above standard deviation is 0, but it is usually preferably 0.1 or more, 0.5 or more is particularly preferred, and 1 or more is more preferred. Therefore, the obtained adhesive has good reproducibility and uniformity of the above optical properties, and can easily satisfy the above color difference ΔE.

In the adhesive composition P, the content of the colorant (C) is preferably 0.001 parts by mass or more, more preferably 0.005 parts by mass or more, particularly preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, and most preferably 0.03 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). When the lower limit of the content of the colorant (C) is as described above, the value of the total light transmittance can be adjusted to a predetermined low level, and the color difference ΔE can be easily satisfied. In addition, the content is preferably 1.3 parts by mass or less, preferably 1.0 parts by mass or less, particularly preferably 0.4 parts by mass or less, more preferably 0.3 parts by mass or less, and most preferably 0.15 parts by mass or less. When the upper limit of the content of the colorant (C) is as described above, the obtained adhesive is likely to exhibit appropriate optical properties and is more likely to satisfy the above color difference ΔE and the above total light transmittance.

(1-4) Active energy ray-hardening component (D) In the adhesive formed by crosslinking the adhesive composition P and hardening it with active energy rays, the active energy ray-hardening component (D) polymerizes with each other, and it is estimated that the polymerized active energy ray-hardening component (D) is entangled in the crosslinking structure (stereoscopic network structure) of the (meth)acrylate polymer (A). The adhesive having such a high-level structure exhibits very excellent durability and is particularly excellent in step-following property and blister resistance under high temperature and high humidity conditions.

The active energy ray-curable component (D) is not particularly limited as long as it is a component that can be cured by active energy ray irradiation and obtain the above-mentioned effect, and can be any monomer, oligomer, or polymer, or a mixture thereof. Among them, a multifunctional acrylate monomer having better anti-foaming property is preferred.

Multifunctional acrylate monomers such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxytrimethylacetic acid neopentyl glycol di(meth)acrylate, dicyclopentyl di(meth)acrylate, tricyclodecane dimethanol (meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloyloxyethyl) isocyanurate, allyl cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl] The 2-functional type of fluorene, etc.; the 3-functional type of trihydroxymethylpropane tri(meth)acrylate, dipentatriol tri(meth)acrylate, propionic acid-modified dipentatriol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide-modified trihydroxymethylpropane tri(meth)acrylate, tris(acryloyloxyethyl)isocyanurate, ε-caprolactone-modified tris(2-(meth)acryloyloxyethyl)isocyanurate, etc.; the 4-functional type of diglycerol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc.; the 5-functional type of propionic acid-modified dipentatriol penta(meth)acrylate, etc.; the 6-functional type of dipentatriol hexa(meth)acrylate, caprolactone-modified dipentatriol hexa(meth)acrylate, etc. These may be used alone or in combination of two or more. 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 obtained adhesive, a polyfunctional acrylate monomer containing an isocyanurate structure in the molecule such as bis(acryloxyethyl)isocyanurate, tris(acryloxyethyl)isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl)isocyanurate, or a polyfunctional acrylate monomer containing a cyclic structure (especially a cycloalkane structure) in the molecule such as tricyclodecanedimethanol (meth)acrylate is preferred, and a polyfunctional acrylate monomer containing an isocyanurate structure in the molecule such as tricyclodecanedimethanol (meth)acrylate is preferred. Preferably, the polyfunctional acrylate monomer is a polyfunctional acrylate monomer having 2 or more functional groups and containing a polycyclic structure (especially a polycyclic structure of cycloalkane) in the molecule, ε-caprolactone-modified β-(2-(meth)acryloyloxyethyl) isocyanurate or tricyclic decanedimethanol (meth)acrylate is particularly preferred, ε-caprolactone-modified β-(2-acryloyloxyethyl) isocyanurate or tricyclic decanedimethanol acrylate is more preferred, and ε-caprolactone-modified β-(2-acryloyloxyethyl) isocyanurate is the most preferred.

In the adhesive composition P, the lower limit of the content of the active energy ray-hardening component (D) is preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, and more preferably 4 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). On the other hand, from the viewpoint of the adhesive strength of the adhesive after active energy ray hardening, the upper limit of the above content is preferably 20 parts by mass or less, particularly preferably 12 parts by mass or less, and more preferably 10 parts by mass or less. From the viewpoint of easily exerting higher adhesive strength, it is preferably 9 parts by mass or less. When the content of the active energy ray-hardening component (D) is within the above range, the adhesive after active energy ray hardening can easily have a suitable value of the gel fraction or adhesive strength, and can be more excellent in the step followability and blister resistance under high temperature and high humidity conditions.

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

Such photopolymerization initiator (E) includes, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-oxolinyl-propane-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, diphenyl ketone, p-phenyldiphenyl ketone, 4,4'-diphenyl ketone, 2-Diethylaminodiphenyl ketone, dichlorodiphenyl ketone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide, etc. These may be used alone or in combination of two or more.

In the adhesive composition P, the content of the photopolymerization initiator (E) is preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, and more preferably 5 parts by mass or more, with respect to 100 parts by mass of the active energy ray-curable component (D). 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.

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

Among the above, the adhesive composition P preferably contains a silane coupling agent. Therefore, even if the adherend is a plastic plate or a glass component, the adhesiveness with the adherend is increased, and the step-following property and blister resistance under high temperature and high humidity conditions are better.

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

Such silane coupling agents include, for example, polysilicic acid unsaturated group-containing silicic acid compounds such as vinyl trimethoxysilane, vinyl triethoxysilane, and methacryloxypropyl trimethoxysilane; 3-glycidoxypropyl trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, and silicic acid compounds having an epoxy structure; 3-butyl propyl trimethoxysilane, 3-butyl propyl triethoxysilane, 3-butyl propyl dimethoxymethyl silane, and silicic acid compounds containing butyl groups. ; 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amine-containing silicon compounds; 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane; or condensates of at least one of these and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane and other alkyl-containing silicon compounds. These may be used alone or in combination of two or more.

The content of the silane coupling agent in the adhesive composition P is preferably 0.01 parts by mass or more, particularly preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more, based on 100 parts by mass of the (meth)acrylate polymer (A). Furthermore, the content is preferably 1 part by mass or less, particularly preferably 0.5 parts by mass or less, and more preferably 0.3 parts by mass or less.

(2) Preparation of adhesive composition The adhesive composition P can be prepared by preparing a (meth)acrylate polymer (A), mixing the obtained (meth)acrylate polymer (A) with a crosslinking agent (B) and a coloring agent (C), and optionally adding an active energy ray-hardening component (D), a photopolymerization initiator (E), an additive, etc.

The (meth)acrylate polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a general free radical polymerization method. The polymerization of the (meth)acrylate polymer (A) is preferably carried out by a solution polymerization method using a polymerization initiator as needed. However, the present invention is not limited thereto, and the polymerization can also be carried out without a solvent. The polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc., can also be used in combination of two or more.

The polymerization initiator may be an azo compound, an organic peroxide, or two or more thereof. Azo compounds include, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropyl ester), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and the like.

Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, isopropyl hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl) peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

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

After obtaining the (meth)acrylate polymer (A), a crosslinking agent (B), a coloring agent (C), and, if necessary, a diluting solvent, an active energy ray-hardening component (D), a photopolymerization initiator (E), an additive, etc. are added to the solution of the (meth)acrylate polymer (A), and after thorough mixing, an adhesive composition P (coating solution) diluted with a solvent is obtained. In addition, when any of the above components is used in a solid state, or when it is mixed with other components in an undiluted state, precipitation occurs, the component may be dissolved alone or diluted in a diluting solvent in advance, and then mixed with other components.

The above-mentioned diluent solvent uses, for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane and vinyl chloride; alcohols such as methanol, ethanol, propanol, butanol, and 1-methoxy-2-propanol; ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; cellosolve solvents such as ethyl cellosolve, etc.

The concentration and viscosity of the coating solution thus prepared are not particularly limited as long as they are within the range that can be coated, 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 diluting solvent is not essential, and if the adhesive composition P has a coating viscosity, no diluting solvent may be added. In this case, the adhesive composition P is a coating solvent in which the polymerization solvent of the (meth)acrylate polymer (A) is directly used as a diluting solvent.

(3) Formation of adhesive layer The adhesive layer 11 of the present embodiment is preferably formed by an adhesive that crosslinks the adhesive composition P (coating layer). The crosslinking of the adhesive composition P can usually be performed by heat treatment. In addition, the heat treatment can also be performed together with the drying treatment when the coating layer of the adhesive composition P applied to the desired object evaporates the dilution solvent.

The heating temperature of the heat treatment is preferably 50 to 150° C., particularly preferably 70 to 120° C. The heating time is preferably 10 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes.

After the heat treatment, a aging period of about 1 to 2 weeks at room temperature (e.g., 23°C, 50% RH) may be provided as needed. If such an aging period is necessary, the adhesive is formed after the aging period, and if an aging period is not necessary, the adhesive is formed after the heat treatment is completed.

Through the above-mentioned heat treatment (and aging), the (meth)acrylate polymer (A) is fully crosslinked through the crosslinking agent (B). The adhesive obtained in this way can easily satisfy the desired values of gel fraction and adhesion, and has excellent step-following property and blister resistance under high temperature and high humidity conditions.

(4) Physical properties of adhesive (gel fraction) In the present embodiment, the gel fraction of the adhesive preferably has a lower limit of 20% or more, preferably 25% or more, and particularly preferably 30% or more. When the lower limit of the gel fraction of the adhesive is as described above, the cohesive force of the adhesive increases, and the adhesive has better step-following properties under high temperature and high humidity conditions. In addition, the upper limit of the gel fraction of the adhesive in the present embodiment preferably has a lower limit of 100%, preferably 90%, particularly preferably 80%, and more preferably 70%. When the upper limit of the gel fraction of the adhesive is as described above, the adhesive will not be too hard, and the adhesive has excellent initial step-following properties and long-term step-following properties. In addition, it becomes a material that exhibits good adhesion and has better adhesion to the adherend. Here, the method for measuring the gel fraction of the adhesive is shown in the test example described later.

In the case of an adhesive hardened by active energy rays, the lower limit of the gel fraction of the adhesive after active energy ray hardening is preferably 40% or more, preferably 45% or more, particularly preferably 50% or more, and most preferably 62% or more. In addition, the upper limit of the gel fraction is preferably 100% or less, preferably 95% or less, particularly preferably 90% or less, and more preferably 85% or less. When the gel fraction of the adhesive after active energy ray hardening is within the above range, the adhesive has better step followability and blister resistance under high temperature and high humidity conditions. In addition, the adhesive has good adhesion and better adhesion to the adherend.

(5) Thickness of adhesive layer The thickness of the adhesive layer 11 preferably has a lower limit of 10 μm or more, preferably 25 μm or more, and particularly preferably 50 μm or more. When the lower limit of the thickness of the adhesive layer 11 is as described above, it is easy to satisfy the above optical properties and to exert the desired adhesive force in accordance with the content of the colorant (C). In addition, from the perspective of easily exerting excellent step followability, the lower limit is preferably 120 μm or more, preferably 140 μm or more, particularly preferably 160 μm or more, and even more preferably 180 μm or more.

In addition, the upper limit of the thickness of the adhesive layer 11 is preferably 1000 μm or less, preferably 500 μm or less, particularly preferably 400 μm or less, and more preferably 300 μm or less. When the upper limit of the thickness of the adhesive layer 11 is as described above, the processability is good. In addition, it is difficult to cause appearance problems such as embossing. Furthermore, it is easy to satisfy the above-mentioned optical properties through the relationship with the content of the coloring agent (C). In addition, the adhesive layer 11 can be formed as a single layer or can be formed by stacking multiple layers.

Furthermore, the thickness of the adhesive layer 11 in the display body 2 is substantially the same as the thickness of the adhesive layer 11 of the adhesive sheet 1 in the present embodiment.

1-2. Peeling sheet The peeling sheets 12a and 12b are used to 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 peeling sheets 12a and 12b are not necessarily required.

The peeling sheets 12a and 12b are made of, for example, polyethylene film, polypropylene film, polybutylene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, ethylene (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Moreover, crosslinked films thereof may be used. Furthermore, laminated films thereof may be used.

It is preferred that the peeling surface of the peeling sheets 12a, 12b (particularly the surface in contact with the adhesive layer 11) is subjected to a peeling treatment. The peeling agent used for the peeling treatment may be, for example, an alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, wax-based, etc. Moreover, it is preferred that one of the peeling sheets 12a, 12b is a heavy-peeling-type peeling sheet with a large peeling force, and the other peeling sheet is a light-peeling-type peeling sheet with a small peeling force.

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

2. Physical properties (1) Haze value The haze value of the adhesive layer 11 is usually 0% or more. When the colorant (C) in the adhesive layer 11 is a dye, it is preferably 0.01% or more, more preferably 0.05% or more, and particularly preferably 0.1% or more. When the colorant (C) in the adhesive layer 11 is a pigment, the haze value of the adhesive layer 11 is preferably 0.1% or more, more preferably 0.5% or more, particularly preferably 1.0% or more, more preferably 1.5% or more, and most preferably 3.0% or more. By setting the lower limit of the haze value of the adhesive layer 11 as above, it is easy to satisfy the color difference ΔE mentioned above. On the other hand, the haze value of the adhesive layer 11 is preferably 80% or less, more preferably 60% or less, particularly preferably 40% or less, preferably 30% or less, and most preferably 20% or less from the viewpoint of visibility. By setting the upper limit of the haze value of the adhesive layer 11 to the above, it is easy to satisfy the above-mentioned total light transmittance and color difference ΔE. In addition, the haze value in this specification is a value measured according to JIS K7361:2000.

(2) Adhesion The adhesive force of the adhesive sheet 1 of the present embodiment to the sodium calcium glass preferably has a lower limit of 3N/25mm or more, preferably 5N/25mm or more, particularly preferably 10N/25mm or more, and more preferably 20N/25mm or more. When the lower limit of the adhesive force is as above, the step-following property and the blister resistance under high temperature and high humidity conditions are better. In addition, the adhesive force of the adhesive sheet 1 of the present embodiment to the sodium calcium glass preferably has an upper limit of 100N/25mm or less, preferably 90N/25mm or less, and particularly preferably 70N/25mm or less. When the upper limit of the adhesive force is as described above, good reworkability can be obtained, and in the event of a bonding error, the display component, especially the expensive display component, can be reused.

Here, the adhesive force in this specification is basically the adhesive force measured by the 180-degree peeling method according to JIS Z0237:2009, but the measurement sample is 25mm wide and 100mm long. The measurement sample is attached to the adherend, pressurized at 0.5MPa and 50℃ for 20 minutes, and then placed under normal pressure, 23℃, 50%RH for 24 hours, and measured at a peeling speed of 300mm/min. In the case of active energy ray-curable adhesives, the adhesive force is the adhesive layer that is cured by active energy rays after being attached to the adherend.

3. Production of adhesive sheet An example of production of adhesive sheet 1 is to apply the coating solution of the adhesive composition P on the peeling surface of a peeling sheet 12a (or 12b), perform heat treatment, and make the adhesive composition P thermally crosslinked to form a coating layer, and then overlap the coating layer and the peeling surface of another peeling sheet 12b (or 12a). In the case where a ripening period is required, the ripening period is passed, and in the case where the ripening period is not required, the coating layer directly becomes the adhesive layer 1. Therefore, the above-mentioned adhesive sheet 1 is obtained. The conditions for the heat treatment and ripening are as described above.

Another example of manufacturing the adhesive sheet 1 is to apply the coating solution of the adhesive composition P on the peelable surface of a peelable sheet 12a, perform a heat treatment, and make the adhesive composition P thermally crosslinked to form a coating layer, thereby obtaining a peelable sheet 12a with a coating layer. In addition, apply the coating solution of the adhesive composition P on the peelable surface of another peelable sheet 12b, perform a heat treatment, and make the adhesive composition P thermally crosslinked to form a coating layer, thereby obtaining a peelable sheet 12b with a coating layer. After that, the peeling sheet 12a with the coating layer and the peeling sheet 12b with the coating layer are bonded together with the coating layers on both sides in contact with each other. Here, a plurality of peeling sheets with coating layers can also be prepared, and the coating layers can be bonded together in the desired number. In the case where the aging period is required, the aging period is passed, and in the case where the aging period is not required, the above-mentioned coating layer directly becomes the adhesive layer 11. Therefore, the above-mentioned adhesive sheet 1 is obtained. According to this manufacturing example, even in the case where the adhesive layer 11 is thick, stable manufacturing can be achieved.

The method of applying the coating solution of the above-mentioned adhesive composition P can utilize, for example, a rod coating method, a knife coating method, a roller coating method, a scraper coating method, a mold coating method, a gravure coating method, etc.

[Manufacturing of display]

In manufacturing the above-mentioned display body 2, in one example, a peeling sheet 12a of the adhesive sheet 1 is peeled off, and the adhesive layer 11 exposed from the adhesive sheet 1 is adhered to the surface of the first display body component 21 on which the printed layer 3 exists.

Afterwards, another peeling sheet 12b is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 is bonded to the second display component 22. In other examples, the bonding order of the first display component 21 and the second display component 22 may be interchanged.

In the case where 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 ray is irradiated to the adhesive layer 11. As a result, the energy ray-curable component (D) in the adhesive layer 11 is polymerized, and the adhesive layer 11 is cured. The energy ray irradiation to the adhesive layer 11 is usually performed through either the first display component 21 or the second display component 22, preferably through the first display component 21 as a protective panel.

Active energy rays refer to electromagnetic waves or charged particle rays that have energy quanta, such as ultraviolet rays or electron rays. Among active energy rays, ultraviolet rays are particularly preferred because they are easy to handle.

Ultraviolet irradiation can be performed by a high-pressure mercury lamp, an electrodeless H lamp, a xenon lamp, etc., and the irradiation intensity of ultraviolet irradiation is preferably about 50 to 1000 mW/ ^cm2 , and preferably about 100 to 500 mW/ ^cm2 . In addition, the light intensity is preferably 50 to 10000 mJ/ ^cm2 , more preferably 200 to 7000 mJ/ ^cm2 , and particularly preferably 500 to 3000 mJ/ ^cm2 . On the other hand, electron beam irradiation can be performed by an electron beam accelerator, etc., and the electron beam irradiation intensity is preferably about 10 to 1000 krad.

The display 2 having the adhesive layer 11 cured by irradiation with active energy rays as described above exhibits excellent blister resistance. For example, when the display 2 is placed under high temperature and high humidity conditions (e.g., 85°C, 85% RH), even if the first display component 21 and/or the second display component 22 degas, blistering, floating, peeling, etc., at the interface between the adhesive layer 11 and the display components 21, 22 is suppressed.

Furthermore, in the display 2, when the adhesive layer 11 is formed of the adhesive composition P, the adhesive layer 11 has excellent step-following property under high temperature and high humidity conditions. Therefore, even if the display 2 is placed under high temperature and high humidity conditions (e.g., 85°C, 85%RH), the occurrence of bubbles, floating, peeling, etc. near the step is suppressed.

[Other displays] The display of another embodiment of the present invention is shown in FIG3. The display 2A of the embodiment of FIG3 has the same structure as the display 2, but the adhesive layer 11 is composed of a laminate of a colored adhesive layer 111 and a colorless adhesive layer 112. In addition, the colorless adhesive layer 112 is located on the side of the printed layer 3 of the convex portion in the first display component 21.

The colored adhesive layer 111 is the same as the adhesive layer 11 of the display 2 and is colored by the colorant. On the other hand, the colorless adhesive layer 112 is not colored by the colorant and is preferably colorless and transparent.

If the colored adhesive layer 111 is located on the side that is in contact with the printed layer 3 in the first display body component 21, the colored adhesive layer 111 is compressed or deformed due to the unevenness of the printed layer 3. Therefore, the color of the colored adhesive layer 111 may be darker or lighter, and the transmittance may be uneven. For example, in the part where the colored adhesive layer 111 is compressed, the color becomes darker and the transmittance may be reduced. In contrast, as described above, by making the layer in contact with the printed layer 3 in the first display body component 21 a colorless adhesive layer 112, the colored adhesive layer 111 can be prevented from being compressed or deformed due to the unevenness of the printed layer 3. By doing so, the transmittance non-uniformity of the adhesive layer 11 can be suppressed, the appearance quality of the display can be improved, and the design can be further improved.

The embodiments described above are recorded for easy understanding of the present invention and are not recorded for limiting the present invention. Therefore, the various elements disclosed in the embodiments described above also include the purpose of all design changes or equivalents within the technical scope of the present invention.

For example, one or both of the release sheets 12a, 12b in the adhesive sheet 1 may be omitted, or the desired optical element may be laminated by replacing the release sheets 12a and/or 12b. Furthermore, the first display component 21 may not have the printed layer 3. In this case, an example of the display 2 may also have a black frame material at the edge. [Example]

The present invention is described in more detail below with reference to embodiments, but the scope of the present invention is not limited to these embodiments.

[Example 1] 1. Preparation of (meth)acrylate polymer 60 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of isoborneol acrylate, 10 parts by mass of N-acryloylmorpholine, and 20 parts by mass of 2-hydroxyethyl acrylate were copolymerized by solution polymerization to prepare a (meth)acrylate polymer (A). The molecular weight of the (meth)acrylate polymer (A) was measured by the method described below, and the weight average molecular weight (Mw) was 500,000.

2. Preparation of adhesive composition 100 parts by weight (solid content conversion value; the same below) of the (meth)acrylate polymer (A) obtained in step 1 above, 0.2 parts by weight of trihydroxymethylpropane-modified toluene diisocyanate (produced by Toyo Chem, product name "BHS8515") as a crosslinking agent (B), 0.04 parts by weight of carbon black-like black pigment (C1) as a coloring agent (C), and ε-caprolactone-modified s-(2-acryloyloxyethyl) isocyanurate (D1; produced by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-9300-1CL) 5.0 parts by weight, a mixture of 1-hydroxycyclohexyl phenyl ketone and diphenyl ketone in a mass ratio of 1:1 as a photopolymerization initiator (E) 0.5 parts by weight, and 3-glycidoxypropyltrimethoxysilane as a silane coupling agent 0.2 parts by weight were mixed, stirred thoroughly, and diluted with methyl ethyl ketone to obtain a coating solution of an adhesive composition.

Here, the formulations (solid content conversion value) of each adhesive composition when the (meth)acrylate polymer (A) is 100 parts by mass (solid content conversion value) are shown in Table 1. In addition, the details of the symbols and the like described in Table 1 are as follows. [(Meth)acrylate polymer (A)] 2EHA: 2-ethylhexyl acrylate IBXA: isoborneol acrylate ACMO: N-acryloylmorpholine HEA: 2-hydroxyethyl acrylate MMA: methyl methacrylate BA: n-butyl acrylate AA: acrylic acid [Crosslinking agent (B)] TDI: trihydroxymethylpropane-modified toluene diisocyanate (manufactured by Toyo Chem, product name "BHS8515") XDI: trihydroxymethylpropane-modified xylene diisocyanate (manufactured by Soken Chemical Co., Ltd., product name "TD-75") Epoxy: 1, 3-bis(N, N-Diepoxypropylaminomethyl)cyclohexane (Mitsubishi Gas Chemical Co., Ltd., product name "TETRAD-C") [Coloring agent (C)] C1~C2: Carbon black-like black pigments with the properties shown in Table 2 [Active energy ray curing component (D)] D1: ε-caprolactone-modified s-(2-acryloyloxyethyl) isocyanurate (Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-9300-1CL") D2: Tricyclodecanedimethanol diacrylate (Shin-Nakamura Chemical Co., Ltd., product name "NK Ester A-DCP")

The haze value (%) of the coloring agent C1-C2 diluted 10,000 times with ethyl acetate was measured using a haze meter (manufactured by Nippon Denshoku Industries, product name "SH-7000", optical path 10 mm) in accordance with JIS K7136:2000. From the measured value, the difference 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 haze value at a wavelength of 780 nm and the average of the haze value at a wavelength of 380 nm, and the standard deviation of the haze value at each wavelength at 5 nm intervals in the wavelength range of 380 nm to 780 nm were calculated. The results are shown in Table 2.

3. Preparation of adhesive sheet The coating solution of the adhesive composition obtained in step 2 was applied by a knife coater to the peeling-treated surface of a heavy-duty release sheet (manufactured by Lintec, product name "SP-PET752150"), one side of which was subjected to a peeling treatment with a silicone-based release agent. Thereafter, the coating layer was heated at 90°C for 1 minute to form a coating layer (thickness: 50 μm), thereby preparing a heavy-duty release sheet with a coating layer.

On the other hand, the coating solution of the adhesive composition obtained in the above step 2 was applied to the peeling-treated surface of a light-peel release sheet (manufactured by Lintec, product name "SP-PET382120") in which one side of a polyethylene terephthalate film was peeled with a silicone-based release agent using a knife coater. Thereafter, the coating layer was heated at 90° C. for 1 minute to form a coating layer (thickness: 50 μm), and 4 light-peel release sheets with a coating layer were prepared.

The surface on the coating layer side of the heavy-peel release sheet with a coating layer obtained above and the surface on the coating layer side of one of the light-peel release sheets with a coating layer obtained above are laminated to obtain a first layer assembly in which a coating layer having a thickness of 100 μm is sandwiched between the heavy-peel release sheet and the light-peel release sheet.

Thereafter, the light-peel release sheet was peeled off from the first layer of the integrated body, and the exposed surface of the coating layer was bonded to the surface of the coating layer side of one of the light-peel release sheets with the coating layer obtained above, thereby obtaining a second layer of the integrated body in which the coating layer with a thickness of 150 μm was sandwiched between the heavy-peel release sheet and the light-peel release sheet. The above steps are repeated to obtain the fourth layer of the integrated body in which the coating layer with a thickness of 250 μm is sandwiched between the heavy peeling type peeling sheet and the light peeling type peeling sheet.

Thereafter, the fourth layer stack was aged at 23° C. and 50% RH for 7 days to produce an adhesive sheet having a structure of heavy-peel release sheet/adhesive layer (thickness: 250 μm)/light-peel release sheet.

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

[Examples 2 to 11, Comparative Examples 1 to 2] Except for changing the types and proportions of the monomers constituting the (meth)acrylate polymer (A), the weight average molecular weight (Mw) of the (meth)acrylate polymer (A), the type and amount of the crosslinking agent (B), the type and amount of the coloring agent (C), the type and amount of the active energy ray curing component (D), the amount of the photopolymerization initiator (E), the amount of the silane coupling agent, and the thickness of the adhesive layer as shown in Table 1, the adhesive sheets were prepared in the same manner as in Example 1. In addition, in Examples 6, 10, and 11, the thickness and the number of layers of the adhesive layer formed on the release sheet were changed to change the thickness of the adhesive layer.

The weight average molecular weight (Mw) mentioned above is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement). ＜Measurement conditions＞ ・GPC measurement apparatus: HLC-8020 manufactured by Tosoh ・GPC column (passed in the following order): manufactured by Tosoh TSK guard column HXL-H TSK gel GMHXL (×2) TSK gel G2000HXL ・Measurement solvent: tetrahydrofuran ・Measurement temperature: 40°C

[Test Example 1] (Measurement of gel fraction) The adhesive sheets obtained in each embodiment and comparative example were cut into a size of 80 mm × 80 mm, and the adhesive layer was wrapped in a polyester net (mesh size 200). The mass was weighed on a precision balance, and the mass of the net alone was subtracted to calculate the mass of the adhesive alone. The mass at this time was M1.

Afterwards, the adhesive wrapped in the polyester mesh is immersed in ethyl acetate at room temperature (23°C) for 24 hours. Then, the adhesive is taken out and air-dried for 24 hours at a temperature of 23°C and a relative humidity of 50%, and then dried in an oven at 80°C for 12 hours. After drying, its mass is weighed on a precision balance, and the mass of the mesh alone is subtracted to calculate the mass of the adhesive alone. The mass at this time is M2. The gel fraction (%) is expressed as (M2/M1)×100. Therefore, the gel fraction of the adhesive (before UV irradiation) is derived. The results are shown in Table 3.

On the other hand, the adhesive layer of the adhesive sheet obtained in the embodiment (except embodiment 7) and the comparative example was irradiated with active energy rays (ultraviolet rays; UV) through a light peeling type peeling sheet under the following conditions to harden the adhesive layer. The adhesive of the hardened adhesive layer was subjected to the same gel fraction (after UV irradiation) as described above. The results are shown in Table 3.

<Active energy ray irradiation conditions> ・High-pressure mercury lamp was used. ・Illuminance: 200mW/ ^cm2 , light intensity: 2000mJ/cm2 ^. UV illuminance and light intensity meter: "UVPF-A1" manufactured by Eye Graphics

[Test Example 2] (Measurement of total light transmittance) The adhesive layer of the adhesive sheet obtained in the embodiment and the comparative example was bonded to glass, and these were used as the measurement sample. In addition to the background measurement using glass, the total light transmittance (%) of the above measurement sample was measured using a haze meter (manufactured by Nippon Denshoku Industries, product name "NDH-5000") in accordance with JIS K7361-1:1997. The results are shown in Table 3.

[Test Example 3] (Measurement of haze value) The haze value (%) of the adhesive layer of the adhesive sheet obtained in the embodiment and the comparative example was measured using a haze meter (manufactured by Nippon Denshoku Industries, product name "NDH-5000") in accordance with JIS K7136:2000. The results are shown in Table 3.

[Test Example 4] (Measurement of L*a*b*) For the adhesive layer of the adhesive sheet obtained in the embodiment and the comparative example, the lightness L* (L*1), chromaticity a* (a*1), and chromaticity b* (b*1) specified in the CIE1976 L*a*b* colorimetric system were measured using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries, product name "SQ2000") in the transmitted light. The results are shown in Table 3.

On the surface of the first glass plate (NSG Precision Co., Ltd., product name "Corning glass Eagle XG", 90 mm long × 50 mm wide × 0.5 mm thick), a UV curable ink (Teikoku Ink Co., Ltd., product name "POS-911 ink") was screen printed in a frame shape (outer shape: 90 mm long × 50 mm wide, 5 mm wide). After that, the printed UV curable ink was cured by irradiating with UV rays (80 W/ ^cm2 , 2 metal halide lamps, lamp height 15 cm, belt speed 10-15 m/min), and a glass plate with a printed layer having a step (step height: 10 μm) caused by the printed layer was produced.

Thereafter, two polarizing plates were bonded together with a transparent adhesive sheet (manufactured by Lintech, product name "OPTERIA MO-T015") interposed therebetween so that the polarization axes became orthogonal polarization states (polarization axes: ∠45°, ∠135°), thereby producing a first layer integrated body consisting of polarizing plate/transparent adhesive sheet/polarizing plate. Furthermore, a second glass plate (manufactured by NSG Precision, product name "Corning glass Eagle XG", 90 mm in length × 50 mm in width × 0.5 mm in thickness) was bonded to the surface of one polarizing plate with a transparent adhesive sheet (manufactured by Lintech, product name "OPTERIA MO-T015") interposed therebetween, thereby producing a second layer integrated body consisting of polarizing plate/transparent adhesive sheet/polarizing plate/transparent adhesive sheet/glass plate. Furthermore, since the two polarizing plates are arranged in cross polarization, the light is in an extinction state.

After the adhesive sheet obtained in the embodiment and the comparative example was cut into 90 mm in length and 50 mm in width, the light peeling type peeling sheet was peeled off from the adhesive sheet, and the exposed adhesive layer was attached to the polarizing plate side of the second layer stack obtained above to prepare the third layer stack. After that, the heavy peeling type peeling sheet was peeled off, and the exposed adhesive layer was attached to the glass plate with a printed step so that the entire surface of the printed layer in the shape of a frame was covered. After that, the active energy line was irradiated through the first glass plate under the same conditions as in the test example 1 to cure the adhesive layer, and these were used as samples. In addition, Example 7 is a state in which active energy rays are not irradiated.

For the non-printed layer portion (equivalent to the display portion in the display body) and the printed layer portion (equivalent to the non-display portion in the display body) of the sample obtained above, a spectrocolorimeter (manufactured by BYK, product name "Spectro  guide") was used to measure the lightness L* (L*2) of the display portion, the chromaticity a* (a*2) of the display portion, and the chromaticity b* (b*2) of the display portion as specified by the CIE1976 L*a*b* colorimetric system, as well as the lightness L* (L*3) of the non-display portion, the chromaticity a* (a*3) of the non-display portion, and the chromaticity b* (b*3) of the non-display portion. The results are shown in Table 3.

From the above results, the color difference ΔE was calculated according to the following formula (I). The results are shown in Table 3.

[Test Example 5] (Measurement of Adhesion)

The light-peel release sheet obtained from the adhesive sheet of the embodiment and the comparative example was peeled off, and the exposed adhesive layer was laminated with the easy-adhesive layer of a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 100μm) having an easy-adhesive layer to obtain a laminate of a heavy-peel release sheet/adhesive layer/PET film. The obtained laminate was cut into 25mm wide and 100mm long pieces, and these were used as samples.

In an environment of 23°C and 50% RH, the heavy-peel release sheet was peeled off from the above sample, and the exposed adhesive layer was attached to sodium calcium glass (manufactured by Nippon Sheet Glass Co., Ltd.), and then pressurized at 0.5MPa and 50°C for 20 minutes in an autoclave manufactured by Kurihara Manufacturing Co., Ltd. After that, it was placed at 23°C and 50% RH for 24 hours.

Afterwards, the above-mentioned PET film was irradiated with active energy rays under the same conditions as in Test Example 1 to cure the adhesive layer. In addition, the adhesive sheet of Example 7 was not irradiated with active energy rays. Afterwards, the adhesion force (N/25mm) was measured using a tensile tester (manufactured by Orientec, product name "Tensilon") at a peeling speed of 300mm/min and a peeling angle of 180 degrees. The conditions other than those described here were measured according to JIS Z0237:2009. The results are shown in Table 3.

[Test Example 6] (Evaluation of appearance coordination)

The samples obtained in Test Example 4 were visually judged under a 3-wavelength fluorescent lamp (distance from the fluorescent lamp: 200 cm) to determine whether the non-printed layer part (equivalent to the display part of the display body) and the printed layer part (equivalent to the non-display part of the display body) were integrated (having a sense of integrity), and the appearance coordination was evaluated according to the following criteria. The results are shown in Table 3.

◎: The non-printing layer and the printing layer are very integrated.

○: The non-printing layer and the printing layer are integrated to a certain extent.

×: The non-printing layer and the printing layer are obviously not fused.

[Test Example 7] (Evaluation of visual recognition)

The adhesive sheets obtained in the examples and comparative examples were cut into 70 mm in length and 70 mm in width, and the adhesive layer of the adhesive sheets was sandwiched between two sodium calcium glass plates (manufactured by Nippon Sheet Glass Co., Ltd., 70 mm in length, 70 mm in width, and 1.1 mm in thickness) for bonding. After that, active energy rays were irradiated through one side of the sodium calcium glass plate under the same conditions as in Test Example 1 to harden the adhesive layer, and these were used as samples. In addition, Example 7 was a state where active energy rays were not irradiated.

On the other hand, on a 15.6-inch monitor with a resolution of 1366×768 (manufactured by Fujitsu, product name "LITEBOOK A574/H"), text with black characters on a white background (font: MS PGothic) was displayed at 100% at a size of 5 to 20 points (1 point scale).

The sample obtained above was placed on the above display. After that, the size of the text that can be visually recognized was confirmed at a distance of 50 cm from the display, and the visibility was evaluated according to the following criteria. The results are shown in Table 3. ◎: 6-point text can be recognized. ○: 6-point text cannot be recognized at all, but 8-point text can be recognized. △: 8-point text cannot be recognized at all, but 15-point text can be recognized. ×: 15-point text cannot be recognized.

[Test Example 8] (Evaluation of step-following property) On the surface of a glass plate (manufactured by NSG Precision, product name "Corning glass Eagle XG", 90 mm long × 50 mm wide × 0.5 mm thick), a UV-curable ink (manufactured by Teikoku Ink Co., Ltd., product name "POS-911 ink") was screen-printed in a frame shape (outer shape: 90 mm long × 50 mm wide, 5 mm wide). After that, the printed UV-curable ink was cured by irradiating with UV rays (80 W/cm ² , 2 metal halide lamps, lamp height 15 cm, belt speed 10 to 15 m/min), and a glass plate with a step (step height: 5 μm, 10 μm) caused by the printed layer was produced.

From the adhesive sheets obtained in the examples and comparative examples, the light-peel release sheet was peeled off, and the exposed adhesive layer was bonded to the easy-adhesion layer of a polyethylene terephthalate (PET) film (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 100 μm) having an easy-adhesion layer. Thereafter, the heavy-peel release sheet was peeled off to expose the adhesive layer. Next, the above-mentioned laminate was laminated on each glass plate with a step difference using a laminator (manufactured by FUJIPLA Co., Ltd., product name "LPD3214") so that the adhesive layer covered the entire surface of the frame-shaped printing. After that, the samples were autoclaved at 50°C and 0.5 MPa for 20 minutes and then placed at normal pressure, 23°C and 50% RH for 24 hours.

Afterwards, the above-mentioned PET film was irradiated with active energy rays under the same conditions as in Test Example 1 to harden the adhesive layer. Then, it was stored under wet and hot conditions of 85°C and 85% RH for 72 hours. Afterwards, the step follow-up was evaluated according to the following criteria. When the printed step was completely buried in the adhesive layer, the step follow-up was judged to be good. When floating or peeling was observed at the interface between the printed step and the adhesive layer, it was judged that the printed step could not be followed. In addition, except that Example 7 was not irradiated with active energy rays, the step follow-up was evaluated in the same manner as above. The results are shown in Table 3. ◎: Good at a printing step of 10μm ○: Good at a printing step of 5μm ×: There is floating and peeling at a printing step of 5μm

[Test Example 9] (Evaluation of blister resistance) The light-peel release sheet was peeled off from the adhesive sheet obtained in the embodiment and the comparative example, and the exposed adhesive layer was adhered to the PC board side of a plastic sheet (manufactured by Mitsubishi Gas Chemicals, product name "Iupilon˙Sheet MR58U", thickness: 0.7 mm, containing ultraviolet absorber) on which PMMA layers were stacked on a PC board, thereby obtaining a plastic sheet with an adhesive layer.

From the plastic plate with adhesive layer obtained above, a heavy peeling release sheet was peeled off, and the plastic plate was attached to a sodium calcium glass plate (manufactured by Nippon Sheet Glass Co., Ltd., thickness: 0.7 mm) of 70 mm × 150 mm through the exposed adhesive layer. Thereafter, it was treated in an autoclave at 50°C and 0.5 MPa for 20 minutes, and then placed at normal pressure, 23°C, and 50% RH for 24 hours. Thereafter, the adhesive layer was irradiated with active energy rays through the plastic plate under the same conditions as in Test Example 1 to cure the adhesive layer.

The obtained laminate was stored at high temperature and high humidity conditions of 85°C and 85% RH for 72 hours. Afterwards, the state of the interface between the adhesive layer and the adherend (plastic plate, glass plate) was visually confirmed, and the blister resistance was evaluated according to the following criteria. In addition, except that Example 7 was not irradiated with active energy rays, the rest was the same as above to evaluate the blister resistance. The results are shown in Table 3. ◎: No bubbles or floating or peeling. ○: No floating or peeling, bubbles were slightly generated, but it was not a problem. △: No floating or peeling, but many bubbles occurred. ×: Floating and peeling occurred.

[Table 1] (Meth)acrylate polymer (A) Crosslinking agent (B) Coloring agent (C) Active energy ray hardening component (D) Photopolymerization initiator (E) Silane coupling agent Adhesive layer thickness Composition M Type Quality Type Quality Type Quality Quality Quality μm Embodiment 1 2EHA/IBXA/ACMO/HEA =60/10/10/20 500,000 TDI 0.2 C1 0.04 D1 5 0.5 0.2 250 Embodiment 2 TDI 0.2 C1 0.02 D1 5 0.5 0.2 250 Embodiment 3 TDI 0.2 C2 0.2 D1 5 0.5 0.2 250 Embodiment 4 TDI 0.2 C1 0.04 D1 5 0.5 - 250 Embodiment 5 XDI 0.2 C1 0.04 D1 5 0.5 0.2 250 Embodiment 6 TDI 0.2 C1 0.06 D1 5 0.5 0.2 150 Embodiment 7 TDI 0.2 C1 0.04 - - - - 250 Embodiment 8 TDI 0.2 C1 0.04 D2 5 0.5 0.2 250 Embodiment 9 2EHA/MMA/HEA =65/15/20 700,000 TDI 0.2 C1 0.04 D1 5 0.5 0.2 250 Embodiment 10 BA/AA=90/10 400,000 Epoxy 0.05 C1 0.04 D1 10 1 0.2 230 Embodiment 11 2EHA/IBXA/ACMO/HEA =60/10/10/20 500,000 TDI 0.2 C1 0.11 D1 5 0.5 0.2 100 Comparison Example 1 TDI 0.2 - - D1 5 0.5 0.2 250 Comparison Example 2 TDI 0.2 C2 1.5 D1 5 0.5 0.2 250

[Table 2] Colorant Type Haze value at wavelength 380nm (%) Haze value at wavelength 780nm (%) Difference of fog value (points) Average fog density (%) Standard deviation of fog 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 (%) Total light transmittance (%) Fog value (%) Adhesive layer Display Non-display part ΔE Adhesion force (N/25 mm) Appearance coordination Visibility Step and follow Foam resistance Before UV irradiation After UV irradiation L*1 a*1 b*1 L*2 a*2 b*2 L*3 a*3 b*3 Embodiment 1 52 62 51.8 4.2 74.4 -1.5 1.2 2.39 0.34 -0.44 2.74 -0.17 -0.20 0.66 50≦ ◎ ◎ ◎ ◎ Embodiment 2 53 63 74.5 4.3 89.9 -0.6 0.1 1.68 0.50 0.02 2.74 -0.17 -0.20 1.27 50≦ ○ ◎ ◎ ◎ Embodiment 3 52 63 46.4 31.5 71.3 0.1 0.9 1.70 0.16 0.03 2.74 -0.17 -0.20 1.12 50≦ ◎ ○ ◎ ◎ Embodiment 4 52 62 51.7 4.3 74.5 -1.5 1.2 2.40 0.33 -0.45 2.74 -0.17 -0.20 0.65 50≦ ◎ ◎ ◎ ◎ Embodiment 5 51 62 50.9 4.6 74.6 -1.4 1.1 2.37 0.32 -0.42 2.74 -0.17 -0.20 0.65 50≦ ◎ ◎ ◎ ◎ Embodiment 6 52 64 59.1 2.0 78.7 -1.7 -0.4 1.58 0.40 -0.49 2.74 -0.17 -0.20 1.32 50≦ ○ ◎ ○ ◎ Embodiment 7 56 - 53.1 4.1 73.8 -1.5 1.3 2.50 0.35 -0.45 2.74 -0.17 -0.20 0.62 50≦ ◎ ◎ ◎ × Embodiment 8 52 61 51.9 4.3 74.4 -1.4 1.2 2.38 0.34 -0.45 2.74 -0.17 -0.20 0.67 50≦ ◎ ◎ ◎ ○ Embodiment 9 65 80 58.0 1.4 78.0 -1.7 -0.9 1.73 0.60 -0.34 2.74 -0.17 -0.20 1.28 25 ○ ◎ ◎ ◎ Embodiment 10 55 70 62.0 0.9 80.2 -1.3 -1.1 1.03 0.20 0.06 2.74 -0.17 -0.20 1.77 38 ○ ◎ ◎ ◎ Embodiment 11 52 63 51.5 4.0 74.2 -1.2 1.1 2.35 0.32 -0.42 2.74 -0.17 -0.20 0.66 45 ◎ ◎ × ◎ Comparison Example 1 52 63 99≦ 0.2 96.9 -0.3 0.3 0.65 0.12 -0.38 2.74 -0.17 -0.20 2.12 50≦ × ◎ ○ ◎ Comparison Example 2 51 58 0.3 92.3 0.1 -2.4 -0.8 2.01 0.16 0.08 2.74 -0.17 -0.20 0.85 50≦ ○ × ○ △

As can be seen from Table 3, the adhesive sheets obtained using the examples are excellent in both appearance coordination and visibility. In addition, the adhesive sheets obtained using the examples other than Example 11 are also excellent in step following performance. Furthermore, the adhesive sheets obtained using the examples other than Example 7 are also excellent in blister resistance. [Industrial Applicability]

The adhesive sheet of the present invention can be suitably used, for example, for laminating a protective panel having a black printed layer to a desired display component.

1: Adhesive sheet 11: Adhesive layer 12a, 12b: Peeling sheet 2, 2A: Display 111: Colored adhesive layer 112: Colorless adhesive layer 21: First display component 22: Second display component 3: Printing layer (convex part)

[Figure 1] is a cross-sectional view of a display body of one embodiment of the present invention. [Figure 2] is a cross-sectional view of an adhesive sheet of one embodiment of the present invention. [Figure 3] is a cross-sectional view of a display body of another embodiment of the present invention.

11: Adhesive layer

2: Display body

21: The first display component

22: The second display component

3: Printing layer (convex part)

Claims (8)

A display having a display portion and a non-display portion, and at least one display component, other display components, and an adhesive layer for bonding the one display component and the other display components, wherein the adhesive layer in the display portion has a total light transmittance of 3% or more, and according to the CIE1976 L*a*b* color system, when the lightness L* of the display portion is L*2, the chromaticity a* of the display portion is a*2, the chromaticity b* of the display portion is b*2, the lightness L* of the non-display portion is L*3, the chromaticity a* of the non-display portion is a*3, and the chromaticity b* of the non-display portion is b*3, the color difference ΔE calculated by the following formula (I) is 2.00 or less

The adhesive constituting the adhesive layer contains a colorant, and the colorant is a black pigment or dye. As the display body of claim 1, wherein the L*3 of the non-display part is 0.1~50, the a*3 of the non-display part is -20~20, and the b*3 of the non-display part is -20~20. A display as claimed in claim 1, wherein the non-display portion is black. A display as claimed in claim 1, wherein at least one of the above-mentioned display component and the above-mentioned other display component has a protrusion on the surface of the adhesive layer side, and the above-mentioned protrusion constitutes a part or all of the above-mentioned non-display part. An adhesive sheet having an adhesive layer for bonding one display component and another display component of a display having a display portion and a non-display portion, wherein the adhesive layer has a total light transmittance of 3% or more, and the adhesive layer is colored so that in the display obtained by bonding the one display component and the other display component via the adhesive layer, the display has a light transmittance of 3% or more according to CIE 1976. According to the L*a*b* color system, when the lightness L* of the display part is L*2, the chromaticity a* of the display part is a*2, the chromaticity b* of the display part is b*2, the lightness L* of the non-display part is L*3, the chromaticity a* of the non-display part is a*3, and the chromaticity b* of the non-display part is b*3, the color difference ΔE calculated by the following formula (I) is less than 2.00

The adhesive constituting the adhesive layer contains a colorant, and the colorant is a black pigment or dye. The adhesive sheet of claim 5, wherein, according to the CIE1976 L*a*b* colorimetric system, when the lightness L* of the adhesive layer is L*1, the chromaticity a* of the adhesive layer is a*1, and the chromaticity b* of the adhesive layer is b*1, the L*1 of the adhesive layer is 5 to 95, the a*1 of the adhesive layer is -20 to 20, and the b*1 of the adhesive layer is -20 to 20. As in claim 5, the adhesive sheet, wherein the haze value of the adhesive layer measured in accordance with JIS K7361:2000 is greater than 0.1% and less than 80%. The adhesive sheet of claim 5 has two peeling sheets, and the adhesive layer is in contact with the peeling surfaces of the two peeling sheets and is sandwiched between the peeling sheets.