JP6947278B2 - Adhesive sheet, method of manufacturing adhesive sheet and method of selecting colorant - Google Patents

Description

The present invention relates to a pressure-sensitive adhesive sheet, a method for producing a pressure-sensitive adhesive sheet, and a method for selecting a colorant.

Conventionally, a display device such as a liquid crystal display (LCD) and an input device used in combination with a display device such as a touch panel have been widely used. In the manufacture of these display devices and input devices, adhesive sheets are used for bonding optical members. In recent years, an adhesive sheet having a black appearance may be required in order to impart a concealing property for design and functionality to the adhesive sheet, and a black double-sided adhesive sheet containing a black pigment in order to impart a light-shielding property. It is known to provide layers (see Patent Documents 1 and 2).

Patent Document 1 describes a double-sided pressure-sensitive adhesive sheet composed of a flexible base material layer, a first black layer and a second black layer, and a laminate including a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer. Therefore, a double-sided pressure-sensitive adhesive sheet is disclosed in which the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are the outermost layers on both sides of the laminate.

Patent Document 2 describes a black foil-like pressure-sensitive adhesive containing a pressure-sensitive adhesive component, a black pigment, and a styrene-maleic acid resin, wherein the content of the black pigment in the black foil-like pressure-sensitive adhesive is 2 to 6 mass by mass. A black foil-like pressure-sensitive adhesive, which is%, is disclosed.

Japanese Unexamined Patent Publication No. 2005-060435 Japanese Unexamined Patent Publication No. 2013-032430

As described above, a black adhesive sheet obtained by coloring a base material or an adhesive is known, but such an adhesive sheet is assumed to be bonded to a transparent member having a black frame or its display surface. No study was made on the design of the transparent member with the black frame and its display surface and the adhesive sheet, especially when the display is off (when the power is off) and the sense of unity with the black frame. ..

An object to be solved by the present invention is to provide an adhesive sheet having an excellent sense of unity with a black frame of a transparent member having a black frame.

As a result of diligent studies to solve the above problems, the present inventors have blended a metal oxide as a colorant in the pressure-sensitive adhesive sheet containing an acrylic polymer, and L ^* a ^* b ^{* of the pressure-sensitive adhesive sheet.} It has been found that an adhesive sheet capable of solving the above problems can be obtained by controlling the ^{L *} value, the a ^* value and the b ^* value in the color system so as to satisfy a predetermined relationship.
Specifically, the configuration and the preferred configuration of the present invention are as follows.

[1] An adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} a ^* b ^* color system L ^* value of 60 or more and less than 90, an a ^* value of less than 0, and a b ^* value of 0 as defined in JIS Z8781-4: 2013. Adhesive sheet that is less than.
[2] The pressure-sensitive adhesive sheet according to [1], wherein the colorant contains at least one metal oxide containing at least one metal oxide selected from the group consisting of copper, iron, manganese, and titanium.
[3] An adhesive sheet containing an acrylic polymer and a colorant.
The colorant comprises at least one metal oxide containing one or more selected from the group of metal types consisting of copper, iron, manganese and titanium.
The adhesive sheet is for laminating transparent members with a black frame.
The adhesive sheet is an adhesive sheet having an L ^* a ^* b ^* color system L ^* value of 60 or more and less than 90 and an a ^* value of less than 0 as defined by JIS Z8781-4: 2013.
[4] The pressure-sensitive adhesive sheet according to any one of [1] to [3], wherein the colorant is a black metal oxide.
[5] An adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a black metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} a ^* b ^* color system L ^* value of 60 or more and less than 90, and an a ^* value of -10.0 or more and less than 0, as defined by JIS Z8781-4: 2013. Sheet.
[6] The adhesive sheet has an a ^* value of -3.0 or more and less than -0.2, and a b ^* value of -20.0 or more and less than 0, any one of [1] to [5]. Adhesive sheet as described in the section.
[7] The pressure-sensitive adhesive sheet according to any one of [1] to [6], wherein the acrylic polymer contains an acrylic monomer unit having a crosslinkable functional group.
[8] The pressure-sensitive adhesive sheet according to any one of [1] to [7], further containing a cross-linking agent.
[9] The pressure-sensitive adhesive sheet according to any one of [1] to [8], which further contains an ultraviolet absorber.
[10] The adhesive sheet according to any one of [1] to [9], wherein the C value represented by the following formula 1 is 9 to 15.
Equation 1:
C = 0.13 × L ^* −b ^*
[11] The adhesive sheet according to [10], which has a C value of 11 to 13.
[12] A method for producing an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
Adhesion in which the L ^{* value in the L *} a ^* b ^* color system specified in JIS Z8781-4: 2013 is 60 or more and less than 90, the a ^* value is less than 0, and the b ^* value is less than 0. The process of sorting sheets;
The colorant contains at least one metal oxide containing at least one selected from the group consisting of copper, iron, manganese, and titanium, and has an L ^* value of 60 or more and less than 90, and an a ^* value. ^{A step of selecting an adhesive sheet having an L *} value of less than 0; and a step of selecting an adhesive sheet having an L * value of 60 or more and less than 90 and an a ^* value of −3.0 or more and less than 0;
A method for manufacturing an adhesive sheet, which comprises any of the steps.
[13] The method for producing an adhesive sheet according to [12], wherein the adhesive sheet has a C value of 9 to 15 represented by the following formula 1.
Equation 1:
C = 0.13 × L ^* −b ^*
[14] A method for selecting a colorant for an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
When producing an adhesive sheet using an acrylic polymer and a colorant,
^{The L *} a ^* b ^{* value in the L * a * b *} color system specified in JIS Z8781-4: 2013 of the adhesive sheet is 60 or more and less than 90, the a ^* value is less than 0, and the b ^* value is less than 0. The process of selecting a colorant to be used;
The adhesive sheet contains at least one metal oxide containing at least one selected from the group consisting of copper, iron, manganese, and titanium, and the L ^* value of the pressure-sensitive adhesive sheet is 60 or more and less than 90, and the a ^* value is ^{A step of selecting a colorant having an L *} value of less than 0; and a step of selecting a colorant having an L * value of 60 or more and less than 90 and an a ^* value of −3.0 or more and less than 0;
A method of selecting a colorant, which comprises any of the steps.
[15] The method for selecting a colorant according to [14], wherein the adhesive sheet has a C value of 9 to 15 represented by the following formula 1.
Equation 1:
C = 0.13 × L ^* −b ^*

[101] An adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} value of 60 or more and less than 90, an a ^* value of less than 0, and is represented by the following formula 1 in the ^{L *} a ^* b ^* color system defined by JIS Z8781-4: 2013. An adhesive sheet having a C value of 9 to 15.
Equation 1:
C = 0.13 × L ^* −b ^*
[102] The pressure-sensitive adhesive sheet according to [101], wherein the acrylic polymer contains an acrylic monomer unit having a crosslinkable functional group.
[103] The pressure-sensitive adhesive sheet according to [101] or [102], which further contains a cross-linking agent.
[104] The pressure-sensitive adhesive sheet according to any one of [101] to [103], which further contains an ultraviolet absorber.
[105] The adhesive sheet according to any one of [101] to [104], which has a C value of 11 to 13.
[106] The item according to any one of [101] to [105], wherein the colorant contains at least one metal oxide containing at least one metal oxide selected from the group consisting of copper, iron and manganese. Adhesive sheet.
[107] A method for producing an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
The L ^{* value in the L *} a ^* b ^* color system specified in JIS Z8781-4: 2013 is 60 or more and less than 90, the a ^* value is less than 0, and the C value represented by the following formula 1 A method for producing an adhesive sheet, which comprises a step of selecting an adhesive sheet having a value of 9 to 15.
Equation 1:
C = 0.13 × L ^* −b ^*
[108] A method for selecting a colorant for an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
When a pressure-sensitive adhesive sheet is produced using an acrylic polymer and a colorant, the L ^* a ^* b ^* color system L ^* value specified in JIS Z8781-4: 2013 of the pressure-sensitive adhesive sheet is 60 or more and less than 90. , A ^* A method for selecting a colorant, which comprises a step of selecting a colorant having a value less than 0 and a C value represented by the following formula 1 of 9 to 15.
Equation 1:
C = 0.13 × L ^* −b ^*

According to the present invention, it is possible to obtain an adhesive sheet having an excellent sense of unity with a black frame of a transparent member having a black frame.

FIG. 1 is a schematic view showing a cross section of an adhesive sheet having a release sheet. 2, the formula 1A obtained by converting the expression 1 relationship between L ^* and b ^* when C value is a lower limit value of 9, a formula 1 if C value is the upper limit value 15 L ^* and b It is a graph summarizing the formula 1B converted into the relational expression with ^{*, and the plots obtained in each Example and Comparative Example.}

Hereinafter, the present invention will be described in detail. The description of the constituent elements described below may be based on typical embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[Adhesive sheet]
A first aspect of the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} a ^* b ^* color system L ^* value of 60 or more and less than 90, an a ^* value of less than 0, and a b ^* value of 0 as defined in JIS Z8781-4: 2013. Is less than.
A second aspect of the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet containing an acrylic polymer and a colorant.
The colorant comprises at least one metal oxide containing one or more selected from the group of metal types consisting of copper, iron, manganese and titanium.
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} a ^* b ^* color system L ^* value of 60 or more and less than 90, and an a ^* value of less than 0, as defined by JIS Z8781-4: 2013.
A third aspect of the pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a black metal oxide,
The adhesive sheet is for laminating transparent members with a black frame.
^{The adhesive sheet has an L *} value of 60 or more and less than 90 and an a ^* value of −3.0 or more and less than 0 ^{in the L *} a ^* b ^* color system defined by JIS Z8781-4: 2013.
Since the adhesive sheet of the present invention has the above-mentioned structure, it is excellent in a sense of unity with the black frame of the transparent member provided with the black frame. In a display in which a black screen is displayed or not displayed, the degree of blackness of the display is increased by adhering the adhesive sheet of the present invention. The sense of unity is emphasized.

<Characteristics of adhesive sheet>
^{The pressure-sensitive adhesive sheet of the present invention has an L *} value of 60 or more and less than 90 in the L * a * b * color system defined by JIS Z8781-4: 2013. The L ^* value is preferably 65 or more, more preferably 70 or more. The L ^* value is preferably 85 or less, more preferably 80 or less. By setting the L ^* value of the adhesive sheet within the above range, the degree of black color development of the display or the like can be more effectively enhanced. It is preferable that the adhesive sheet can enhance its design when it is attached to a display or the like displaying a black screen. Specifically, when the adhesive sheet is attached to a display displaying a black screen, the degree of black color development (preferability of the degree of blackness) of the display can be increased. As a result, the sense of unity with the transparent member provided with the black frame can be enhanced. Further, it is preferable that the design of the transparent member provided with the black frame can be enhanced. The L ^* value of the pressure-sensitive adhesive sheet is preferably controlled by controlling the type and amount of the colorant and controlling the thickness of the pressure-sensitive adhesive sheet.

^{The pressure-sensitive adhesive sheet of the present invention preferably has an a *} value of less than 0, more preferably less than −0.2 in the L * a * b * color system defined in JIS Z8781-4: 2013. , -0.4 or less is particularly preferable. The a ^* value is preferably -10.0 or more, more preferably -3.0 or more, particularly preferably -2.0 or more, and more particularly preferably -1.0 or more. preferable. By setting the a ^* value of the adhesive sheet within the above range, the sense of unity with the transparent member provided with the black frame can be enhanced.
^{The pressure-sensitive adhesive sheet of the present invention preferably has a b *} value of -20.0 or more, preferably -10.0 or more, in the L * a * b * color system defined by JIS Z8781-4: 2013. Is more preferable, and −5.0 or more is particularly preferable. The b ^* value is preferably less than 0, more preferably −0.4 or less. By setting the b ^* value of the adhesive sheet within the above range, the sense of unity with the transparent member provided with the black frame can be enhanced. ^{It is preferable to control the a *} value and the b ^* value of the pressure-sensitive adhesive sheet by controlling the type and amount of the colorant and controlling the type and amount of the ultraviolet absorber.

The pressure-sensitive adhesive sheet of the present invention preferably has a C value represented by the following formula 1 of 9 to 15. The C value is more preferably 10 or more, and particularly preferably 11 or more. The C value is more preferably 14 or less, and particularly preferably 13 or less. By setting the C value of the adhesive sheet within the above range, the sense of unity with the transparent member provided with the black frame can be enhanced. The C value of the pressure-sensitive adhesive sheet is preferably controlled by controlling the type of colorant or the type of ultraviolet absorber.
Equation 1:
C = 0.13 × L ^* −b ^*

The thickness of the pressure-sensitive adhesive sheet is preferably 1 μm or more, more preferably 10 μm or more, and further preferably 20 μm or more. The thickness of the pressure-sensitive adhesive sheet is preferably 5000 μm or less, more preferably 3000 μm or less, and even more preferably 1000 μm or less. By setting the thickness of the adhesive sheet to the above upper limit value or less, it is possible to prevent water vapor from entering from the end portion and improve the durability. On the other hand, by setting the thickness of the pressure-sensitive adhesive sheet to the above lower limit value or more, it is possible to facilitate the handling of the pressure-sensitive adhesive sheet and to make it easy to use for bonding optical members that are required to be thinned.

<Structure of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention may be a single-layer pressure-sensitive adhesive sheet. Further, the pressure-sensitive adhesive sheet may be a single-sided pressure-sensitive adhesive sheet having a base material (preferably a transparent base material) on one side, or a double-sided pressure-sensitive adhesive sheet. The double-sided adhesive sheet includes a single-layer adhesive sheet composed of an adhesive layer, a multi-layer adhesive sheet in which a plurality of adhesive layers are laminated, and a multi-layer adhesive in which another adhesive layer is laminated between the adhesive layers. A multi-layered pressure-sensitive adhesive sheet in which a support is laminated between a sheet, a pressure-sensitive adhesive layer and a pressure-sensitive adhesive layer, and a multi-layered pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer is laminated on one side of the support and another pressure-sensitive adhesive layer is laminated on the other side. Can be mentioned. When the double-sided adhesive sheet has a support, it is preferable to use a transparent support as the support. As the support, a general film used in the optical field can be used as in the case of the transparent substrate. Since such a double-sided pressure-sensitive adhesive sheet is also excellent in transparency of the pressure-sensitive adhesive sheet as a whole, it can be suitably used for bonding optical members to each other.

As shown in FIG. 1, the present invention may relate to an adhesive sheet with a release sheet having a release sheet 12a and a release sheet 12b on both surfaces of the adhesive sheet 11. As the release sheet, a releaseable laminated sheet having a release sheet base material and a release layer provided on one side of the release sheet base material, or a polyolefin film such as a polyethylene film or a polypropylene film as a low-polarity base material can be used. Can be mentioned.

Papers and polymer films are used as the base material for the release sheet in the releaseable laminated sheet. In optical applications, polymer films are preferably used to prevent foreign matter from entering. As the release agent constituting the release layer, for example, a general-purpose addition-type or condensation-type silicone-based release agent or a long-chain alkyl group-containing compound is used. In particular, an addition type silicone release agent having high reactivity is preferably used.
Specific examples of the silicone-based release agent include BY24-4527 and SD-7220 manufactured by Toray Dow Corning Silicone, and KS-3600, KS-774, and X62-2600 manufactured by Shin-Etsu Chemical Co., Ltd. Can be mentioned. Further, it contains a silicone resin which is an organic silicon compound having an SiO ₂ units and _{(CH 3) 3 SiO 1/2} units or _{CH 2 = CH (CH 3)} SiO 1/2 units in the silicone-based release agent preferable. Specific examples of the silicone resin include BY24-843, SD-7292, SHR-1404, etc. manufactured by Toray Dow Corning Silicone Co., Ltd., KS-3800, X92-183, etc. manufactured by Shin-Etsu Chemical Co., Ltd.
A commercially available product may be used as the peelable laminated sheet. For example, a heavy separator film which is a release-treated polyethylene terephthalate film manufactured by Mitsubishi Chemical Corporation and a light separator film which is a release-treated polyethylene terephthalate film manufactured by Mitsubishi Chemical Corporation can be mentioned.

When the pressure-sensitive adhesive sheet of the present invention is a double-sided pressure-sensitive adhesive sheet, it is preferable to have a pair of release sheets having different peeling forces. That is, it is preferable that the release sheet has different peelability between one release sheet and the other release sheet in order to facilitate peeling. When the peelability from one side and the peelability from the other side are different, it becomes easy to peel off only the release sheet having the higher peelability first.

<Composition of adhesive sheet>
(Acrylic polymer)
The acrylic polymer is not particularly limited as long as it has an acrylic monomer unit, but is preferably an acrylic copolymer. The acrylic copolymer preferably contains, for example, a non-crosslinkable (meth) acrylic acid ester unit (a1) and an acrylic monomer unit (a2) having a crosslinkable functional group. In the present specification and claims, the "unit" is a repeating unit (monomer unit) constituting the polymer. In addition, the acrylic polymer means a (meth) acrylic polymer, that is, a methacrylic polymer is also included.

The non-crosslinkable (meth) acrylic acid ester unit (a1) is preferably a repeating unit derived from the (meth) acrylic acid alkyl ester. Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, isopropyl (meth) acrylic acid, n-butyl (meth) acrylic acid, and (meth). Isobutyl acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, ( Isooctyl acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, (meth) Examples thereof include n-dodecyl acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth) acrylate. One of these may be used alone, or two or more thereof may be used in combination.
Among the above (meth) acrylic acid alkyl esters, since the adhesiveness is high, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate At least one selected from is preferable.

The acrylic monomer unit (a2) having a crosslinkable functional group is selected from a carboxy group-containing monomer unit, a hydroxy group-containing monomer unit, an amino group-containing monomer unit, and a glycidyl group-containing monomer unit. At least one type is preferable, and at least one type selected from a hydroxy group-containing monomer unit, an amino group-containing monomer unit, and a glycidyl group-containing monomer unit is more preferable. That is, the acrylic polymer preferably has at least one crosslinkable functional group selected from a carboxy group, a hydroxy group, an amino group, an amide group, a glycidyl group and an isocyanate group, and preferably has a hydroxy group, an amino group and an amide group. , It is more preferable to have at least one crosslinkable functional group selected from a glycidyl group and an isocyanate group.
Examples of the carboxy group-containing monomer unit include acrylic acid and methacrylic acid.
The hydroxy group-containing monomer unit is a repeating unit derived from the hydroxy group-containing monomer. Examples of the hydroxy group-containing monomer include hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate. Examples thereof include (meth) acrylic acid [(mono, di or poly) alkylene glycol] such as mono (meth) acrylic acid mono (diethylene glycol), and (meth) acrylic acid lactone such as (meth) acrylic acid monocaprolactone.
Examples of the amino group-containing monomer unit include repeating units derived from amino group-containing monomers such as (meth) acrylamide and allylamine.
Examples of the glycidyl group-containing monomer unit include repeating units derived from a glycidyl group-containing monomer such as glycidyl (meth) acrylate.

The content of the acrylic monomer unit (a2) having a crosslinkable functional group in the acrylic polymer is preferably 0.01 to 40% by mass, more preferably 0.5 to 35% by mass. By setting the content of the acrylic monomer unit (a2) having a crosslinkable functional group within the above range, it becomes easy to control the crosslinkability and adhesiveness of the acrylic polymer.

The acrylic polymer may further contain a unit derived from an alkoxyalkyl group-containing (meth) acrylate. The alkoxyalkyl group-containing (meth) acrylate is an alkoxyalkyl (meth) acrylate. As the alkoxyalkyl (meth) acrylate, for example, an alkoxyalkyl (meth) acrylate having an alkoxy group having 1 to 12 carbon atoms and an alkylene group bonded to the alkoxy group having 1 to 18 carbon atoms is preferable. The alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms, and particularly preferably 1 or 2 carbon atoms. The alkylene group bonded to the alkoxy group preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, further preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.

Examples of such alkoxyalkyl (meth) acrylates include 2-methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxymethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, and the like. Examples thereof include 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, and 4-ethoxybutyl (meth) acrylate.

The acrylic polymer may further contain a unit derived from the nitrogen-containing monomer. The nitrogen-containing monomer is a monomer containing a nitrogen element in one molecule. Examples of the nitrogen-containing monomer include dimethylacrylamide, diethylacrylamide, acryloylmorpholin, hydroxyethylacrylamide, methylolacrylamide, methoxymethylacrylamide, ethoxymethylacrylamide, dimethylaminoethylacrylamide, N-vinylcaprolactam, and N-vinyl-2-. Examples thereof include pyrrolidone, dimethylaminoethyl (meth) acrylate, and N-vinylformamide. Among them, the nitrogen-containing monomer is preferably at least one selected from an acrylamide derivative, an amino group-containing monomer and a nitrogen-containing heterocyclic ring-containing monomer, and more preferably an acrylamide derivative. The acrylamide derivative is more preferably at least one selected from dimethylacrylamide, diethylacrylamide and acryloylmorpholine, and particularly preferably diethylacrylamide.

The acrylic polymer may have other monomeric units, if desired. The other monomer may be a monomer copolymerizable with the above-mentioned acrylic monomer, and examples thereof include (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, and vinylpyridine. The content of the other monomer unit in the acrylic polymer is preferably 20% by mass or less, and more preferably 15% by mass or less.

The acid value of the acrylic polymer is preferably 50 mgKOH / g or less, more preferably 40 mgKOH / g or less, further preferably 30 mgKOH / g or less, and even more preferably 20 mgKOH / g or less. It is even more preferably 10 mgKOH / g or less, and particularly preferably 5 mgKOH / g or less. The acid value of the acrylic polymer may be 0 mgKOH / g. By setting the acid value of the acrylic polymer within the above range, the color loss property of the pressure-sensitive adhesive sheet can be effectively suppressed. Specifically, by setting the acid value of the acrylic polymer within the above range, it is possible to suppress an increase in the total light transmittance even when the pressure-sensitive adhesive sheet is left under high temperature and high humidity conditions for a long time. can. The total light transmittance before and after the pressure-sensitive adhesive sheet is placed in an environment of 85 ° C. and a relative humidity of 85% for 240 hours is measured, and the amount of change in the total light transmittance calculated from the value is preferably less than 10%. Further, the total light transmittance after the pressure-sensitive adhesive sheet is placed in an environment of 85 ° C. and a relative humidity of 85% for 240 hours is preferably less than 85%. The amount of change in the total light transmittance is calculated by the following formula.
Amount of change (%) = (total light transmittance of the sample before treatment)-(total light transmittance of the sample after treatment)

The acid value of the acrylic polymer is measured according to JIS K 0070 (1992). Specifically, first, about 2 g of a sample is precisely weighed in a 100 ml Erlenmeyer flask with a precision balance, and 10 ml of a mixed solvent of ethanol / diethyl ether = 1/1 (weight ratio) is added thereto to dissolve the sample. Further, add 1 to 3 drops of a phenolphthalein ethanol solution as an indicator to this container, and stir sufficiently until the sample becomes uniform. This is titrated with a 0.1N potassium hydroxide-ethanol solution, and the end point of neutralization is when the indicator has a light red color for 30 seconds. The value obtained from the result using the following calculation formula (1) is used as the acid value of the sample.
Acid value (mgKOH / g) = [B × f × 5.611] / S (1)
In the calculation formula (1), B is the amount (ml) of the 0.1N potassium hydroxide-ethanol solution used, f is the factor of the 0.1N potassium hydroxide-ethanol solution, and S is the sample sample. The amount collected (g).

The weight average molecular weight of the acrylic polymer is preferably 100,000 to 2 million, more preferably 200,000 to 1.5 million. The weight average molecular weight of the acrylic polymer is a value before cross-linking with a cross-linking agent described later. The weight average molecular weight is a value measured by size exclusion chromatography (SEC) and determined based on polystyrene. As the acrylic polymer, a commercially available one may be used, or one synthesized by a known method may be used.
The solution viscosity of the acrylic polymer is preferably 1,000 to 10,000 mPa · s, more preferably 1,500 to 8,000 mPa · s, as the solution viscosity of the 35 mass% solution at 23 ° C.

(Colorant)
The pressure-sensitive adhesive sheet of the present invention contains a colorant. The colorant is a metal oxide.
By using a metal oxide as the colorant, it is possible to more effectively enhance the sense of unity with the black frame, the design, and the visibility of the adhesive sheet. Further, as compared with the case where a dye is used, when a metal oxide is used, the cross-linking reaction at the time of producing the pressure-sensitive adhesive sheet is less likely to be inhibited, and the color loss resistance is also excellent.

The metal oxide is preferably a black pigment. Metal oxides include copper oxide, iron tetraoxide, manganese dioxide, barium titanate, potassium titanate, iron titanate, copper-chromium oxide, copper-manganese oxide, copper-iron-manganese oxide, and copper. -Chrome-manganese oxide or copper-iron-chromium oxide, titanium black such as titanium oxynitride and titanium oxide can be mentioned. In the present specification, the metal oxynitride is included in the metal oxide. Among them, the colorant more preferably contains at least one kind of metal oxide containing at least one selected from the group consisting of copper, iron, manganese and titanium as the metal type, and from the group consisting of copper, iron and manganese. It is particularly preferable to contain at least one type of metal oxide containing one or more selected types. The metal type means a metal ion constituting a metal oxide. By selecting the above type as the colorant, the color stability becomes good. The metal type may be singular or plural (single oxide or composite oxide).
As the colorant, only one kind of metal oxide may be used alone, or two or more kinds of metal oxides may be used as a mixture.

The colorant is preferably fine particles. The primary average particle size of the colorant is preferably 0.01 μm or more. Further, the primary average particle size of the colorant is preferably less than 5 μm, more preferably less than 3 μm, further preferably less than 1 μm, and particularly preferably less than 0.5 μm. By setting the primary average particle size of the colorant within the above range, the visibility of the pressure-sensitive adhesive sheet can be improved more effectively.

Content per unit area of the colorant in the pressure-sensitive adhesive sheet is preferably 0.03~0.25g / ^{m 2,} more preferably from 0.05~0.20g / ^{m 2,} 0. It is particularly preferably 10 to 0.18 g / m ^2.
Regardless of the thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet, if the colorant is adjusted to be contained in the above range per unit area, the visibility and the sense of unity with the black frame of the transparent member having the black frame can be enhanced.

The colorant is preferably mixed with the acrylic polymer in a state of being dispersed in the dispersed resin. Examples of the dispersion resin include polyester resin, urethane resin, acrylic resin, and polyether resin.

(Crosslinking agent)
The pressure-sensitive adhesive sheet of the present invention preferably contains a cross-linking agent. The cross-linking agent can be appropriately selected in consideration of the reactivity of the acrylic polymer with the cross-linking functional group. For example, it can be selected from known cross-linking agents such as isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, and butylated melamine compounds. Among these, it is preferable to use an isocyanate compound or an epoxy compound because the hydroxy group-containing (meth) acrylate can be easily crosslinked. That is, the cross-linking agent is preferably at least one selected from a bifunctional or higher functional epoxy compound and a bifunctional or higher functional isocyanate compound, and more preferably a bifunctional or higher functional isocyanate compound.

Examples of the isocyanate compound include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like. Examples of commercially available products include tolylene diisocyanate compounds (manufactured by Tosoh Corporation, Coronate L), tolylene diisocyanate adducts of trimethylolpropane (manufactured by Tosoh Co., Ltd., coronate L-55E), and xylylene diisocyanate compounds (Mitsui). Takenate D-110N) manufactured by Kagaku Co., Ltd. and the like.
Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol di. Glycidyl ether, tetraglycidyl xylene diamine, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, trimethylolpropan polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc. Can be mentioned.
Examples of commercially available products are 1,3-bis (N, N-diglycidylaminomethyl) benzene (or N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine); Mitsubishi Gas Chemical Company. TETRAD-X manufactured by Mitsubishi Gas Chemical Company, Inc.), 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (TETRAD-C manufactured by Mitsubishi Gas Chemical Company, Inc.) and the like can be mentioned.

The content of the cross-linking agent in the pressure-sensitive adhesive sheet is appropriately selected according to the desired adhesiveness and the like, but is preferably 0.01 to 5 parts by mass, preferably 0.1 to 3 parts by mass, based on 100 parts by mass of the acrylic polymer. Parts by mass are more preferred. By setting the content of the cross-linking agent within the above range, the processability of the pressure-sensitive adhesive sheet can be further improved. As the cross-linking agent, one type may be used alone or two or more types may be used in combination, and when two or more types are used in combination, the total mass is preferably within the above range.

(UV absorber)
The pressure-sensitive adhesive sheet of the present invention may contain an ultraviolet absorber. The ultraviolet absorber can be appropriately selected in consideration of the sense of unity with the black frame, the design property, and their light resistance (color loss resistance). For example, it can be selected from known ultraviolet absorbers such as benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, benzoate-based compounds, and hindered amine-based compounds (light stabilizers). Among these, it is preferable to use a hydroxyphenyltriazine-based compound from the viewpoint of being able to strongly absorb the long wavelength portion (UV-A region) of ultraviolet rays.

Examples of the triazine-based compound include hydroxyphenyltriazine and the like. Examples of commercially available products include hydroxyphenyltriazine compounds (manufactured by BASF Japan Ltd., Tinuvin 477) and the like.
Examples of the benzotriazole-based compound include benzotriazole and the like. Examples of commercially available products are Benzotriazole acid, 3- (2H-benzotriazole-2-yl) -5- (1,1-dimethylthyl) -4-hydroxy-, C7-9-brunched and liner alkyl esters (BASF Japan). Company-made, Tyrosine 384-2) and the like can be mentioned.

The content of the ultraviolet absorber in the pressure-sensitive adhesive sheet is appropriately selected according to the desired light resistance (color loss resistance) and the like, but is 0.01 to 5 parts by mass with respect to 100 parts by mass of the acrylic polymer. Preferably, 0.1 to 3 parts by mass is more preferable. By setting the content of the ultraviolet absorber within the above range, the processability of the pressure-sensitive adhesive sheet can be further improved. As the ultraviolet absorber, one type may be used alone or two or more types may be used in combination, and when two or more types are used in combination, the total mass is preferably within the above range.

(solvent)
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive sheet of the present invention may contain a solvent. In this case, the solvent is used to improve the coating suitability of the pressure-sensitive adhesive composition. Examples of the solvent include hydrocarbons such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane and methylcyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, trichloroethylene, tetrachloroethylene and dichloropropane; methanol, ethanol, Alcohols such as propanol, isopropyl alcohol, butanol, isobutyl alcohol, diacetone alcohol; ethers such as diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone; methyl acetate , Ethyl acetate, butyl acetate, isobutyl acetate, amyl acetate, ethyl butyrate, etc .; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Examples thereof include polyols such as glycol monomethyl ether acetate and derivatives thereof.

The content of the solvent in the pressure-sensitive adhesive composition is not particularly limited, but is preferably 25 to 500 parts by mass, more preferably 30 to 400 parts by mass with respect to 100 parts by mass of the acrylic polymer.
The content of the solvent is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, based on the total mass of the pressure-sensitive adhesive composition. One type of solvent may be used alone, two or more types may be used in combination, and when two or more types are used in combination, the total mass is preferably within the above range.

(Other ingredients)
The pressure-sensitive adhesive sheet may contain components other than the above as long as the effects of the present invention are not impaired. Examples of other components include components known as additives for adhesives. For example, a plasticizer, an antioxidant, a metal corrosion inhibitor, a tackifier, a silane coupling agent, an acid scavenger, and the like can be selected as necessary.
Examples of the plasticizer include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, and benzoate. Examples thereof include carboxylic acid vinyl esters such as vinyl acetate and styrene.
Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. One type of these antioxidants may be used alone, or two or more types may be used in combination.
As the metal corrosion inhibitor, a benzoriazole-based resin can be mentioned as a preferable example because of the compatibility and high effect of the pressure-sensitive adhesive.
Examples of the tackifier include rosin resin, terpene resin, terpene phenol resin, Kumaron inden resin, styrene resin, xylene resin, phenol resin, petroleum resin and the like.
Examples of the silane coupling agent include a mercaptoalkoxysilane compound (for example, a mercapto group-substituted alkoxy oligomer).

<Use of adhesive sheet>
The adhesive sheet of the present invention is used for bonding transparent members having a black frame. However, if there is a black part in a part of the transparent member, the black part is used as a black frame. That is, the black frame is not limited to the one that surrounds the entire circumference of the transparent member.
Examples of the transparent member provided with the black frame include members such as windows of buildings and side glasses of vehicles, and optical members such as touch panels and image display devices. Above all, the pressure-sensitive adhesive sheet of the present invention is preferably for bonding optical members. Examples of the optical member provided with the black frame include a smartphone, a television, and an in-vehicle display, and an in-vehicle display is particularly preferable. In-vehicle displays include car navigation systems; head-up displays (HUD); back monitors, side mirror displays, rear view mirrors, and other room mirror displays; center information display (CID), instrument panel, multi-information display, digital Meters and other functional displays; on-dash monitors, headrest monitors, sun visor monitors, other stationary displays; rear seat entertainment (RSE), other entertainment displays and the like.
When the pressure-sensitive adhesive sheet of the present invention is used for bonding optical members, the pressure-sensitive adhesive sheet may be used for bonding to each component in an optical product, a shatterproof film to be bonded to a cover lens on the outermost layer, or the like. It is preferable, and above all, it is particularly preferable that it is used for the purpose of sticking to a touch panel. Examples of the touch panel provided with the black frame include a car navigation system and a CID touch panel type display.
Examples of the constituent members of the touch panel include an ITO film in which an ITO film is provided on a transparent resin film, an ITO glass in which an ITO film is provided on the surface of a glass plate, and a transparent conductive film in which a transparent resin film is coated with a conductive polymer. Examples include hard coat films and fingerprint resistant films. Examples of the constituent members of the image display device include an antireflection film, an alignment film, a polarizing film, a retardation film, and a luminance improving film used in a liquid crystal display device.
Examples of the material used for these members include glass, polycarbonate, polyethylene terephthalate, polymethylmethacrylate, polyethylene naphthalate, cycloolefin polymer, triacetyl cellulose, polyimide, and cellulose acylate.

[Manufacturing method of adhesive sheet]
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited.

<Step of applying the pressure-sensitive adhesive composition to form a coating film>
The method for producing the pressure-sensitive adhesive sheet preferably includes a step of applying the pressure-sensitive adhesive composition on the release sheet to form a coating film.
The coating of the pressure-sensitive adhesive composition can be carried out using a known coating device. Examples of the coating device include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a micro gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater and the like.

<Process of heating the coating film>
The method for producing the pressure-sensitive adhesive sheet preferably includes a step of heating the coating film. In this case, a known heating device such as a heating furnace or an infrared lamp can be used to heat the coating film formed by applying the pressure-sensitive adhesive composition. After heating the coating film, an aging treatment may be performed in which the pressure-sensitive adhesive sheet is allowed to stand at a constant temperature for a certain period of time. The aging treatment can be carried out, for example, by allowing it to stand at 23 ° C. for 7 days.

The present invention may relate to a method for producing a laminate having the above-mentioned pressure-sensitive adhesive sheet and a transparent member, and a method for producing the above-mentioned laminate having the pressure-sensitive adhesive sheet and a transparent member. When the laminate is manufactured, the step of attaching the adhesive sheet to the transparent member is included.

<Process of sorting adhesive sheets>
The method for producing an adhesive sheet of the present invention preferably includes a step of selecting the adhesive sheet. Specifically, the method for producing a pressure-sensitive adhesive sheet of the present invention is a method for manufacturing a pressure-sensitive adhesive sheet containing an acrylic polymer and a colorant, wherein the colorant is a metal oxide and the pressure-sensitive adhesive sheet is attached with a transparent member having a black frame. It is a common use, and the L ^* a ^* b ^{* value in the L * a * b *} color system specified in JIS Z8781-4: 2013 is 60 or more and less than 90, the a ^* value is less than 0, and the b ^* value is. Step of sorting adhesive sheets less than 0;
The colorant contains at least one metal oxide containing at least one selected from the group consisting of copper, iron, manganese, and titanium, and has an L ^* value of 60 or more and less than 90, and an a ^* value. ^{A step of selecting an adhesive sheet having an L *} value of less than 0; and a step of selecting an adhesive sheet having an L * value of 60 or more and less than 90 and an a ^* value of −3.0 or more and less than 0;
It is preferable to include any one of the steps.
In the step of selecting the pressure-sensitive adhesive sheet, it is more preferable that the pressure-sensitive adhesive sheet to be sorted has a C value of 9 to 15 represented by the following formula 1.
C = 0.13 × L ^* −b ^*
The process of selecting the adhesive sheet is not particularly limited. ^{For example, the L *} value, a ^* value, and b ^* value of the sample in the state of the adhesive sheet manufactured by the above method or the state of the laminated body having the adhesive sheet and the transparent member are measured, the C value is calculated, and each value is calculated. Only the samples within the range of the above can be selected as the pressure-sensitive adhesive sheet of the present invention, and defective products outside the range of the remaining values can be excluded.
Further, using a commercially available adhesive sheet as a sample, the L ^* value, a ^* value and b ^* value of the sample are measured to calculate the C value, and only the sample within the range of each value is selected as the adhesive sheet of the present invention. , Defective products that are out of the range of the remaining values can be excluded.
^{In addition, the L *} value, a ^* value, and b ^{* of the} sample are sampled from a commercially available pressure-sensitive adhesive composition in the state of a pressure-sensitive adhesive sheet or a state of a laminate having a pressure-sensitive adhesive sheet and a transparent member by the above method. The value can be measured, the C value can be calculated, only the samples within the range of each value can be selected as the adhesive sheet of the present invention, and the remaining defective products outside the range of each value can be excluded. In this case, when a large number of defective products outside the range of each value are produced, a step of adjusting the composition of the pressure-sensitive adhesive composition by adding the above-mentioned preferable colorant to the commercially available pressure-sensitive adhesive composition is performed. Further, it is preferable to produce an adhesive sheet.

[How to select a colorant]
The method for selecting a colorant of the present invention is a method for selecting a colorant for a pressure-sensitive adhesive sheet containing an acrylic polymer and a colorant, wherein the colorant is a metal oxide and the pressure-sensitive adhesive sheet is a transparent member having a black frame. is for bonding, in the case of producing a pressure-sensitive adhesive sheet using an acrylic polymer and the colorant, JIS of the pressure-sensitive adhesive sheet Z8781-4: ^{L *} value in defined in 2013 ^{L * a} * ^b * color system A step of selecting a colorant ^{having an a *} value of less than 0 and a b ^* value of less than 0, which is 60 or more and less than 90;
The adhesive sheet contains at least one metal oxide containing at least one selected from the group consisting of copper, iron, manganese, and titanium, and the L ^* value of the pressure-sensitive adhesive sheet is 60 or more and less than 90, and the a ^* value is ^{A step of selecting a colorant having an L *} value of less than 0; and a step of selecting a colorant having an L * value of 60 or more and less than 90 and an a ^* value of −3.0 or more and less than 0;
Including any one of the steps.
In the step of selecting the colorant, the pressure-sensitive adhesive sheet preferably has a C value of 9 to 15 represented by the following formula 1.
C = 0.13 × L ^* −b ^*
The process of selecting the colorant is not particularly limited. For example, a pressure-sensitive adhesive composition is prepared by adding the above-mentioned preferable acrylic polymer to an arbitrary colorant, a pressure-sensitive adhesive sheet is produced, and the state of the pressure-sensitive adhesive sheet produced by the above method or the pressure-sensitive adhesive sheet is used. ^{It is possible to measure the L *} value, a ^* value, and b ^* value of the sample in the state of the laminated body having the transparent member, calculate the C value, and confirm whether or not a sample within the range of each value can be obtained. can. In particular, since the b ^* value and the C value vary greatly depending on the type of the colorant, the colorant that facilitates the production of the pressure-sensitive adhesive sheet of the present invention can be selected by the step of selecting such a colorant.

The features of the present invention will be described in more detail with reference to Examples and Comparative Examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limited by the specific examples shown below.

[Example 1]
<Synthesis of acrylic polymer A>
Acrylic polymer A was prepared by solution polymerization in ethyl acetate. Butyl acrylate (BA) and 2-hydroxyethyl acrylate (2HEA) were blended at a mass ratio of 70:30, and AIBN (azobisisobutyronitrile) was dissolved in the solution as a radical polymerization initiator. The solution was heated to 60 ° C. and randomly copolymerized to obtain an acrylic polymer A. The solution viscosity of the 35% by mass solution of the acrylic polymer A at 23 ° C. was 6,400 mPa · s. The acid value of the acrylic polymer A was 0.0 mgKOH / g.

<Preparation of adhesive composition>
Acrylic polymer A, isocyanate cross-linking agent (ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct, Coronate L-55E, manufactured by Toso Co., Ltd.), MO colorant (copper, iron, metal that is a manganese-based oxide) Oxide, manufactured by Dainichi Seika Kogyo Co., Ltd., TM Black 3550), UV absorber C (hydroxyphenyltriazine compound, manufactured by BASF Japan Co., Ltd., Tinuvin 477), UV absorber D (benzotriazole compound, BASF Japan) By mixing Tinuvin 384-2) manufactured by Co., Ltd. and a solvent (ethyl acetate), 0.5 parts by mass of the cross-linking agent, 0.06 parts by mass of the colorant, and ultraviolet rays with respect to 100 parts by mass of the acrylic polymer A. A pressure-sensitive adhesive composition containing a total of 2.00 parts by mass of an absorbent and having a solid content concentration of 30% by mass was obtained.

<Preparation of adhesive sheet>
The pressure-sensitive adhesive composition was applied onto a first release sheet (heavy separator film, Mitsubishi Chemical Corporation, mold-released polyethylene terephthalate film). The coating was carried out using a doctor blade YD type manufactured by Yoshimitsu Seiki Co., Ltd. so that the thickness after drying was 100 μm. Then, it was dried in a hot air dryer at 100 ° C. for 3 minutes to remove the solvent, and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer was formed.
A second release sheet (light separator film, manufactured by Mitsubishi Chemical Corporation), which has been subjected to a mold release treatment that is more peelable than the first release sheet, is attached to one side of this adhesive sheet, and the adhesive sheet with the release sheet is attached. The adhesive sheet of Example 1 was obtained. In the pressure-sensitive adhesive sheet of Example 1, the content of the MO colorant contained in the pressure-sensitive adhesive layer per unit area is 0.06 g / m ² . In the pressure-sensitive adhesive sheets of the other Examples and Comparative Examples, the content of the MO colorant contained in the pressure-sensitive adhesive layer per unit area is the blending amount of the MO colorant in the pressure-sensitive adhesive composition and the adhesion after drying. It is proportional to the thickness of the agent sheet.

[Example 2]
Adhesive in the same manner as in Example 1 except that the blending amount of the colorant was changed so that the content of the MO colorant was 0.17 parts by mass and the thickness of the pressure-sensitive adhesive sheet after drying was changed to 50 μm. An adhesive sheet with an agent composition and a release sheet was obtained.

[Example 3]
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that the blending amount of the colorant was changed so that the content of the MO colorant was 0.17 parts by mass.

[Example 4]
An adhesive composition and an adhesive sheet with a release sheet were obtained in the same manner as in Example 1 except that the thickness of the adhesive sheet after drying was changed to 250 μm.

[Example 5]
Acrylic polymer A, epoxy cross-linking agent (N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine), manufactured by Mitsubishi Gas Chemicals Co., Ltd., TETRAD-X), MO colorant (copper, Iron, metal oxide which is a manganese oxide, manufactured by Dainichi Seika Kogyo Co., Ltd., TM Black 3550), UV absorber C (hydroxyphenyltriazine compound, manufactured by BASF Japan Co., Ltd., Tinuvin 477), UV absorber By mixing D (benzotriazole compound, Tinuvin 384-2 manufactured by BASF Japan Co., Ltd.) and a solvent (ethyl acetate), 0.5 parts by mass of the cross-linking agent is colored with respect to 100 parts by mass of the acrylic polymer A. A pressure-sensitive adhesive composition containing 0.23 parts by mass of the agent and 2.00 parts by mass of the ultraviolet absorber in total was obtained, and the solid content concentration was 30% by mass. Using the pressure-sensitive adhesive composition thus obtained, a pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1.

[Example 6]
<Synthesis of acrylic polymer B>
Acrylic polymer B was prepared by solution polymerization in ethyl acetate. 2-Mesterethyl acrylate monomer (MEA), 2-hydroxyethyl acrylate monomer (2HEA), methyl methacrylate (MMA), dimethylacrylamide (DMAA) and butyl acrylate (BA) in a mass ratio of 70:10: 10: 5: 5. AIBN (azobisisobutyronitrile) was dissolved in the solution as a radical polymerization initiator. The solution was heated to 60 ° C. and randomly copolymerized to obtain an acrylic polymer B. The solution viscosity of the 35% by mass solution of the acrylic polymer B at 23 ° C. was 2,000 mPa · s. The acid value of the acrylic polymer B was 0.0 mgKOH / g.

<Preparation of adhesive composition and adhesive sheet>
Acrylic polymer B, epoxy cross-linking agent (N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine), manufactured by Mitsubishi Gas Chemical Company, TETRAD-X), MO colorant (copper, By mixing iron, metal oxide which is a manganese oxide, TM Black 3550) manufactured by Dainichi Seika Kogyo Co., Ltd., and a solvent (ethyl acetate), a cross-linking agent can be obtained with respect to 100 parts by mass of the acrylic polymer B. A pressure-sensitive adhesive composition containing 0.05 parts by mass and 0.11 parts by mass of a colorant and having a solid content concentration of 30% by mass was obtained. An adhesive sheet with a release sheet was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive composition thus obtained was coated so that the thickness after drying was 50 μm.

[Examples 7 to 9]
Implementation except that the blending amount of the colorant was changed so that the content of the MO colorant would be the amount shown in Table 1 below, and the thickness of the adhesive sheet after drying would be the thickness shown in Table 1 below. An adhesive composition and an adhesive sheet with a release sheet were obtained in the same manner as in Example 6.

[Comparative Example 1]
Acrylic polymer A, epoxy cross-linking agent (N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine), manufactured by Mitsubishi Gas Chemical Company, TETRAD-X), CB colorant (carbon black) , Toyo Color Co., Ltd., Multilac A 903 Black) and solvent (ethyl acetate) are mixed to contain 1.1 parts by mass of the cross-linking agent and 1.1 parts by mass of the cross-linking agent with respect to 100 parts by mass of the acrylic polymer A. A pressure-sensitive adhesive composition containing 0.14 parts by mass and having a solid content concentration of 30% by mass was obtained. Using the pressure-sensitive adhesive composition thus obtained, a pressure-sensitive adhesive sheet with a release sheet was obtained in the same manner as in Example 1.

[Comparative Example 2]
Adhesive in the same manner as in Comparative Example 1 except that the blending amount of the colorant was changed so that the content of the CB colorant was 0.83 parts by mass and the thickness of the pressure-sensitive adhesive sheet after drying was changed to 50 μm. An adhesive sheet with an agent composition and a release sheet was obtained.

[Comparative Example 3]
Adhesive in the same manner as in Comparative Example 1 except that the blending amount of the colorant was changed so that the content of the CB colorant was 0.28 parts by mass and the thickness of the pressure-sensitive adhesive sheet after drying was changed to 250 μm. An adhesive sheet with an agent composition and a release sheet was obtained.

[Example 10]
<Synthesis of acrylic polymer C>
Acrylic polymer C was prepared by solution polymerization in ethyl acetate. Butyl acrylate (BA), 2 ethylhexyl methacrylate (2EHMA), ethyl acrylate (EA), 2 hydroxyethyl methacrylate (2HEMA) and acrylic acid (AA) are blended in a mass ratio of 85: 5: 4: 4: 2. Then, AIBN (azobisisobutyronitrile) was dissolved in the solution as a radical polymerization initiator. The solution was heated to 60 ° C. and randomly copolymerized to obtain an acrylic polymer C. The solution viscosity of the 35% by mass solution of the acrylic polymer C at 23 ° C. was 3,650 mPa · s. The acid value of the acrylic polymer C was 1.6 mgKOH / g.

<Preparation of adhesive composition>
Acrylic polymer C, cross-linking agent (N, N, N', N'-tetraglycidyl-1,3-benzenedi (methaneamine) (manufactured by Mitsubishi Gas Chemical Company, TETRAD-X)), MO colorant (Mikuni) By mixing MHI Black # PD-376M), which is titanium oxide manufactured by Dye Co., Ltd., and 2) and a solvent (ethyl acetate), the cross-linking agent is 0.1% by mass with respect to 100 parts by mass of the acrylic polymer C. A pressure-sensitive adhesive composition containing 1 part by mass of a colorant and having a solid content concentration of 30% by mass was obtained.

<Preparation of adhesive sheet>
The pressure-sensitive adhesive composition was applied onto a first release sheet (heavy separator film, Mitsubishi Chemical Corporation, mold-released polyethylene terephthalate film). The coating was carried out using a doctor blade YD type manufactured by Yoshimitsu Seiki Co., Ltd. so that the thickness after drying was 25 μm. Then, it was dried in a hot air dryer at 100 ° C. for 3 minutes to remove the solvent, and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer was formed.
A second release sheet (light separator film, manufactured by Mitsubishi Chemical Corporation), which has been subjected to a mold release treatment that is more peelable than the first release sheet, is attached to one side of this adhesive sheet, and the adhesive sheet with the release sheet is attached. The adhesive sheet of Example 10 was obtained. In the pressure-sensitive adhesive sheet of Example 10, the content of the MO colorant contained in the pressure-sensitive adhesive layer per unit area is 0.25 g / m ² .

[Measurement of optical characteristics]
The light release separator, which is the second release sheet, is peeled off from the adhesive sheets of each Example and Comparative Example, and a PET film (Cosmo Shine A4300 # 100 manufactured by Toyobo Co., Ltd.) is used in place of the peeled separator using a hand roller. They were bonded together to prepare a laminated film. This laminated film was cut into a size of 50 mm in width and 50 mm in length, and the first release sheet was peeled off. Next, the exposed adhesive surface was attached to a slide glass (manufactured by Matsunami Glass Co., Ltd., S9112) using a hand roller. In this state, it was held in an autoclave under the conditions of 40 ° C. and 5 atm for 30 minutes to be brought into close contact with the glass plate.
For the obtained laminate sample, ^{L *} , a ^* and b ^{* in the L *} a ^* b ^* color system were measured according to JIS Z8781-4: 2013. Further, the C value represented by the following formula 1 was obtained. The obtained results are shown in Table 1 below.
Equation 1:
C = 0.13 × L ^* −b ^*
Incidentally, the slide glass used was colorless and transparent, resulting ^L *, ^{a *} and ^{b *} of the pressure-sensitive adhesive sheet ^L *, was used as ^{a *} and ^{b *.}

For reference, the following formula 1A obtained by converting the expression 1 relationship between L ^* and b ^* when C value is a lower limit value of 9, a formula 1 if C value is the upper limit value 15 and L ^* The following ^{equation 1B converted into the relational expression with b *} and the plots obtained in each Example and Comparative Example are summarized in FIG. The horizontal axis of FIG. 2 is L ^* , and the vertical axis is b ^* .
Equation 1A:
b ^* = 0.13 × L ^* -9
Equation 1B:
b ^* = 0.13 × L ^* -15
From FIG. 2, it can be seen that the pressure-sensitive adhesive sheet of each example using the metal oxide has a C value represented by the formula 1 satisfying 9 to 15.

[evaluation]
<A sense of unity with the black frame>
A laminated body sample was prepared in the same manner as in the optical characteristic measurement, and evaluated by placing it on a display having a black frame in a state where a black screen was displayed and a state in which the black screen was turned off (when the power was turned off). The obtained results are shown in Table 1 below.
◯: Compared to when nothing is placed, the boundary with the black frame around the display becomes less noticeable, and the sense of unity is enhanced.
×: No change. Or, the boundary with the black frame around the display is conspicuous and there is no sense of unity.

<Design>
A laminate sample was prepared in the same manner as in the optical characteristic measurement, and evaluated by placing it on a display having a black frame and displaying a black screen. The obtained results are shown in Table 1 below.
◯: It looked blacker than when nothing was put on it.
×: No change.

From Table 1 above, it was found that the adhesive sheet of the present invention obtained in each example was excellent in a sense of unity with the black frame of the transparent member provided with the black frame. On the other hand, the adhesive sheet obtained in the comparative example had an a ^* value (-3.0 or more) outside the range of less than 0, and a b ^* value outside the range of less than 0. It does not contain a colorant which is a "metal oxide containing at least one selected from the group consisting of manganese and titanium", and the sense of unity with the black frame of the transparent member provided with the black frame is inferior.

1 Adhesive sheet with release sheet 11 Adhesive sheet 12a Release sheet 12b Release sheet

Claims (8)

An adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide
The colorant comprises at least one metal oxide containing at least one selected from the group consisting of copper, iron, manganese and titanium.
The adhesive sheet is for laminating a transparent member having a black frame.
The pressure-sensitive adhesive sheet, JIS Z8781-4: ^{L *} values in the the ^L * ^a * ^{b *} color system defined in 2013 is less than 60 or more 90, ^{a *} value Ri der less than 0, and the following formula 1 in C value represented is Ru der 9-15, pressure-sensitive adhesive sheet.
Equation 1:
C = 0.13 × L ^* −b ^* The pressure-sensitive adhesive sheet according to claim 1, wherein the acrylic polymer contains an acrylic monomer unit having a crosslinkable functional group. The pressure-sensitive adhesive sheet according to claim 1 or 2 , further comprising a cross-linking agent. The adhesive sheet according to any one of claims 1 to 3 , further comprising an ultraviolet absorber. The adhesive sheet according to any one of claims 1 to 4, wherein the C value is 11 to 13. The adhesive sheet according to any one of claims 1 to 4, wherein the C value is 12 or more. A method for producing an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide
The adhesive sheet is for laminating a transparent member having a black frame .
Before SL colorant, metal type copper, iron, a metal oxide containing at least one selected from the group consisting of manganese and titanium comprises at least one, and the L ^* value is less than 60 or more 90, the a ^* value of Ri der less than 0, and C value represented by the following formula 1 contains more engineering of selecting the adhesive sheet Ru der 9-15, a manufacturing method of the pressure-sensitive adhesive sheet.
Equation 1:
C = 0.13 × L ^* −b ^* A method of selecting a colorant for an adhesive sheet containing an acrylic polymer and a colorant.
The colorant is a metal oxide
The adhesive sheet is for laminating a transparent member having a black frame.
When the pressure-sensitive adhesive sheet is produced using the acrylic polymer and the colorant ,
Metallic type copper, iron, a metal oxide containing at least one selected from the group consisting of manganese and titanium comprises at least one, and is said L ^* value is less than 60 or more 90 of the adhesive sheet, wherein a ^* value Ri is Do less than 0, and C value represented by the following formula 1 contains more Engineering selecting the colorant Do that with 9-15, a method of selecting a colorant.
Equation 1:
C = 0.13 × L ^* −b ^*

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