JP7256856B2 - colored adhesive sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a colored pressure-sensitive adhesive sheet used for laminating members constituting a display body, and a display body using the colored pressure-sensitive adhesive sheet.

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

As described above, in display bodies including those for in-vehicle use, when the display body is turned off, it is required to provide a sense of unity with the peripheral members of the display body, for example, the frame material, and to improve the design. Sometimes. For this purpose, it is conceivable to color the display. For example, Patent Documents 1 to 4 disclose inventions relating to the coloring of the display.

JP-A-2000-313871 JP 2009-188298 A JP 2012-234028 A JP 2017-57375 A

However, the techniques disclosed in Patent Literatures 1 to 4 have different purposes of coloring, and therefore have not been able to give a sense of unity to the display member with the surrounding members and improve the design.

The present invention has been made in view of the actual situation as described above, and an object of the present invention is to provide a colored pressure-sensitive adhesive sheet capable of improving the design of a display, and a display with improved design.

In order to achieve the above objects, firstly, the present invention provides a colored pressure-sensitive adhesive layer made of a pressure-sensitive adhesive containing a coloring agent for bonding one display body constituent member and another display body constituent member. wherein the average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, of the colored adhesive layer is 1% or more and 60% or less. (Invention 1).

According to the above invention (Invention 1), when a colored pressure-sensitive adhesive layer that satisfies the above physical properties is applied to a display, it is possible to improve the design of the display when the display is turned off, particularly the appearance harmony. . For example, the display body can be given a sense of unity with peripheral members (particularly, a black frame member or the like).

In the above invention (invention 1), it is preferable that the difference between the haze value of the colored pressure-sensitive adhesive layer at a wavelength of 780 nm and the haze value at a wavelength of 380 nm is 15 points or less (invention 2).

In the above inventions (inventions 1 and 2), the standard deviation of the haze value of the colored pressure-sensitive adhesive layer at each wavelength of 5 nm pitch in the wavelength region of 380 nm to 780 nm is preferably 5 or less (invention 3).

In the above inventions (Inventions 1 to 3), the total light transmittance of the colored pressure-sensitive adhesive layer is 10% or more and less than 95%, and is defined by the CIE1976 L*a*b* color system of the colored pressure-sensitive adhesive layer. It is preferable that the chromaticity a* and chromaticity b* to be obtained are -7 to 7 (Invention 4).

In the above inventions (inventions 1 to 4), the average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, of the liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is 1%. Above, it is preferable that it is 60% or less (Invention 5).

In the above inventions (inventions 1 to 5), the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm in a solution obtained by diluting the colorant 10,000 times with ethyl acetate is 30 points or less. (Invention 6).

In the above inventions (Inventions 1 to 6), the colorant is preferably a black pigment (Invention 7).

In the above inventions (inventions 1 to 7), the adhesive is preferably an acrylic adhesive (invention 8).

In the above inventions (Inventions 1 to 8), the adhesive is a crosslinked adhesive composition containing a (meth)acrylic acid ester polymer (A), a crosslinking agent (B) and a colorant (C). (Invention 9).

In the above inventions (inventions 1 to 9), it is preferable to include two release sheets and the colored adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets ( Invention 10).

Secondly, the present invention comprises one display body constituent member, another display body constituent member, and a colored pressure-sensitive adhesive layer for adhering the one display body constituent member and the other display body constituent member together. (Invention 11), wherein the colored adhesive layer is the colored adhesive layer of the colored adhesive sheet (Inventions 1 to 10).

In the above invention (invention 11), it is preferable that at least one of the one display body constituent member and the other display body constituent member has a step on the side bonded by at least the colored pressure-sensitive adhesive layer ( Invention 12).

In the above inventions (Inventions 11 and 12), it is preferable to have a black frame material (Invention 13).

According to the colored pressure-sensitive adhesive sheet of the present invention, it is possible to improve the designability of the display. Moreover, the display body according to the present invention has improved designability.

1 is a cross-sectional view of a colored pressure-sensitive adhesive sheet according to one embodiment of the present invention; FIG. 1 is a cross-sectional view of a display body according to an embodiment of the invention; FIG. 1 is a plan view of a display having a frame material according to one embodiment of the present invention; FIG.

Embodiments of the present invention will be described below.
[Colored adhesive sheet]
A colored pressure-sensitive adhesive sheet according to an embodiment of the present invention includes a colored pressure-sensitive adhesive layer made of a pressure-sensitive adhesive containing a colorant for bonding one display body constituent member and another display body constituent member. Preferably, a release sheet is laminated on one side or both sides of the colored pressure-sensitive adhesive layer. The display body and display body constituent members will be described later.

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

1. Each member 1-1. Colored Adhesive Layer The average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, of the colored adhesive layer 11 of the colored adhesive sheet 1 according to the present embodiment is 1% or more and 60% or less. be. The haze value in this specification is a value measured according to JIS K7136:2000.

When the colored pressure-sensitive adhesive layer 11 satisfying the above physical properties is applied to a display, it can improve the design of the display when the display is turned off. One example of such design properties is the appearance harmony when the light is turned off. In this case, it is possible to impart a feeling of unity to the display body with the peripheral member, for example, a black frame member, thereby making it possible to give a high-class feeling. Specifically, when the average haze is 1% or more, when the display is turned off, the light incident on the screen of the display is appropriately scattered, making it difficult to see the boundary between the display section and its peripheral members. (seamless). This improves the sense of unity between the display body and the peripheral member when the display body is turned off. On the other hand, when the average haze is 60% or less, the whitishness of the screen of the display is suppressed when the display is turned off, and the sense of unity with the surrounding members is improved. That is, when the average haze is 1% or more and 60% or less, it is possible to impart a sense of unity between the display body and the peripheral members when the display body is turned off, and to present an excellent appearance. be able to. According to the colored adhesive sheet 1 according to the present embodiment, it is possible to improve the designability of the display in this way.

Specifically, the peripheral member has a lightness L* of 23.2, a chromaticity a* of -0.5, and a chromaticity b* of -1. 5, such as an automobile dashboard. The color of the peripheral member preferably has a lightness L* of 5 to 90, a chromaticity a* of −40 to 40, and a chromaticity b* of −40 to 40, particularly lightness L*. is 10 to 80, the chromaticity a* is -30 to 30, the chromaticity b* is preferably -30 to 30, the lightness L* is preferably 15 to 70, and the chromaticity a* is -20 to 20 and the chromaticity b* is preferably -20 to 20. The colored pressure-sensitive adhesive sheet 1 according to this embodiment can be suitably used for a display body having peripheral members of the above colors.

The average haze is required to be 1% or more, preferably 1.5% or more, particularly 1%, from the viewpoint of making it difficult to see the boundary between the display portion and its peripheral members when the display is turned off. It is preferably 0.8% or more, more preferably 2.2% or more. On the other hand, the average haze is required to be 60% or less, preferably 45% or less, and 30% or less from the viewpoint of suppressing whitishness of the screen of the display when the display is turned off. is more preferably 20% or less, and more preferably 12% or less.

The value (absolute value) of the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm of the colored adhesive layer 11 in the present embodiment is preferably 15 points or less, particularly 10 points or less. Preferably, it is 7 points or less. As a result, when the colored pressure-sensitive adhesive layer 11 of the present embodiment is applied to a display, the color balance on the screen does not change when the display is turned on, regardless of the viewing position or angle. As a result, when the display is lit, the visibility of images and video when viewed from a wide range of angles (wide-angle visibility) is improved, and good image quality can be provided.

The lower limit of the difference in haze value may be 0 points, but it is preferably 1 point or more, and 2 points or more, from the viewpoint that the average haze can be easily adjusted to a desired value. is more preferable, particularly preferably 3 points or more, and further preferably 4 points or more.

The haze value at a wavelength of 780 nm of the colored pressure-sensitive adhesive layer 11 in the present embodiment is preferably 0.00, from the viewpoint of facilitating the adjustment of the above-described average haze, the value of the difference between the haze values, and the standard deviation of the haze values described below to desired values. It is preferably 1 to 50%, more preferably 0.5 to 30%, particularly preferably 0.7 to 20%, further preferably 1 to 10%.

In addition, the haze value at a wavelength of 380 nm of the colored pressure-sensitive adhesive layer 11 in the present embodiment is such that the above-described average haze, the value of the difference between the haze values, and the standard deviation of the haze values described later can be easily adjusted to desired values. It is preferably 0.1 to 60%, more preferably 1 to 40%, particularly preferably 2 to 30%, further preferably 4 to 20%, and 5 to 15%. is most preferred.

The standard deviation of the haze value of the colored pressure-sensitive adhesive layer 11 in the present embodiment at each wavelength of 5 nm pitch in the wavelength region of 380 nm to 780 nm (that is, 380 nm, 385 nm, 390 nm, ..., 775 nm, 780 nm) is 5 or less. It is preferably 3 or less, more preferably 2 or less. As a result, when the colored pressure-sensitive adhesive layer 11 of the present embodiment is applied to a display, the color balance on the screen does not change when the display is turned on, regardless of the viewing position or angle. As a result, when the display is lit, the visibility of images and video when viewed from a wide range of angles (wide-angle visibility) is improved, and good image quality can be provided.

The lower limit of the standard deviation is most preferably 0, but usually preferably 0.1 or more, particularly preferably 0.4 or more, and further preferably 0.8 or more is preferred.

The total light haze value of the colored pressure-sensitive adhesive layer 11 in the present embodiment is 0.1 to 60% from the viewpoint of facilitating the adjustment of the above-described average haze, difference in haze values, and standard deviation to desired values. preferably 0.5 to 40%, particularly preferably 1 to 30%, further preferably 1.5 to 20%, preferably 2 to 15% Most preferred.

The total light transmittance (value measured according to JIS K7361-1:1997) of the colored adhesive layer 11 in the present embodiment is preferably 10% or more and less than 95%, and the colored adhesive layer 11 The chromaticity a* and the chromaticity b* defined by the CIE1976 L*a*b* color system are preferably -7 to 7, respectively. The methods for measuring the chromaticity a* and the chromaticity b* in this specification are as shown in the test examples described later.

When the colored pressure-sensitive adhesive layer 11 satisfies the above optical properties, when applied to a display body, the blackness of the display body increases when the display body is turned off, and the design properties of the display body (as an example, the appearance harmony when the display is turned off). can be improved. Specifically, it is possible to further improve the sense of unity between the display body, particularly the in-vehicle display body, and the peripheral member, for example, the black frame material. In addition, when the total light transmittance is 10% or more, it is possible to ensure good visibility as a display (visibility of images and videos due to brightness of the screen).

The upper limit of the total light transmittance is preferably less than 95%, and not more than 90%, from the viewpoint of facilitating the adjustment of the average haze, the difference in haze values, and the standard deviation to desired values. is more preferably 85% or less, and more preferably 80% or less. In addition, the lower limit of the total light transmittance is preferably 25% or more, more preferably 40% or more, particularly preferably 50% or more, from the viewpoint of visibility of the display. is preferably 60% or more.

The chromaticity a* is preferably -7 to 7, more preferably -5 to 5, and particularly preferably -3 to 3, from the viewpoint of the design of the display as described above. Further, it is preferably -1 to 1. In addition, the chromaticity b* is preferably -7 to 7, more preferably -5 to 5, and particularly -3 to 3, from the viewpoint of the design of the display body described above. It is preferably -1 to 1.

On the other hand, the lightness L* defined by the CIE1976 L*a*b* color system of the colored pressure-sensitive adhesive layer 11 makes it easy to adjust the above-mentioned average haze to 1% or more, and the boundary between the display body and the peripheral member is visible. From the viewpoint of difficulty, it is preferably 99 or less, more preferably 95 or less, particularly preferably 92 or less, and further preferably 91 or less. In addition, the lightness L* can easily adjust the above-mentioned average haze value to 60% or less to suppress the whitishness of the screen, or the above-mentioned difference value and standard deviation of the haze value can be set to desired values. From the viewpoint of being able to easily adjust to the Most preferred.

The optical physical properties described above can be achieved by appropriately selecting the type and content of the colorant contained in the pressure-sensitive adhesive that constitutes the colored pressure-sensitive adhesive layer 11 .

The coloring agent has a lower limit of 1% or more of the average haze value, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, in a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate. is preferred, particularly preferably 2% or more, more preferably 3% or more. The upper limit of the average haze of the coloring agent is preferably 60% or less, preferably 40% or less, particularly preferably 30% or less, and further preferably 25% or less. things are preferred. By using an appropriate amount of such a coloring agent, the aforementioned average haze of the colored pressure-sensitive adhesive layer 11 is easily satisfied.

Further, the colorant preferably has a difference value of 30 points or less between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm in a solution obtained by diluting the colorant 10,000 times with ethyl acetate. A score of 25 points or less is more preferable, a score of 20 points or less is particularly preferable, and a score of 16 points or less is more preferable. By using an appropriate amount of such a coloring agent, the difference in haze value of the colored pressure-sensitive adhesive layer 11 described above can be easily satisfied.

The lower limit of the difference in the haze value may be 0 points, but the average haze of the colored adhesive layer 11 may be easily adjusted to 1% or more. From the viewpoint of facilitating the adjustment of the haze value difference and the standard deviation to desired values, it is preferably 0.1 point or more, particularly preferably 0.5 point or more, and further preferably 1 point or more. Preferably.

The haze value at a wavelength of 780 nm of a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is preferably 0.1 to 50%, more preferably 0.5 to 40%, and particularly 1 to 50%. It is preferably 30%, more preferably 2-25%. Further, the haze value at a wavelength of 380 nm of a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is preferably 1 to 60%, more preferably 3 to 50%, and particularly 6 to 40%. and more preferably 10 to 30%. This makes it easier to satisfy the average haze, the difference in haze values, and the standard deviation of haze values, which will be described later.

Furthermore, a standard haze value of a solution obtained by diluting the colorant 10,000 times with ethyl acetate at each wavelength of 5 nm pitch in the wavelength range of 380 nm to 780 nm (that is, 380 nm, 385 nm, 390 nm, ..., 775 nm, 780 nm) The deviation is preferably 10 or less, more preferably 8 or less, particularly preferably 6 or less, further preferably 5 or less. The lower limit of the standard deviation is most preferably 0, but usually preferably 0.1 or more, particularly preferably 0.2 or more, and further preferably 0.3 or more is preferred. This makes it easier to satisfy the standard deviation of the haze value of the colored adhesive layer 11 described above.

The coloring agent may be a pigment or a dye. The pigment may be an inorganic pigment or an organic pigment. Inorganic pigments are preferred from the viewpoint of the durability of the pressure-sensitive adhesive to be obtained. The color of the coloring agent can be appropriately selected according to the color of the peripheral member to give a sense of unity. Black is preferred, and black is particularly preferred.

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

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

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

The pigments or dyes described above can be appropriately mixed and used so that the desired physical properties are obtained in the colored pressure-sensitive adhesive layer 11 .

Among the above colorants, carbon black, nigrosine-based black dyes, and chromate-based black dyes are preferable from the viewpoints of easily satisfying the physical properties described above and easily producing a sense of unity with peripheral members. The surface of the carbon black may or may not be subjected to a predetermined treatment (for example, a solvent-affinity treatment).

The type of adhesive constituting the colored adhesive layer 11 of the colored adhesive sheet 1 according to the present embodiment is not particularly limited, and examples include acrylic adhesives, polyester adhesives, polyurethane adhesives, and rubber adhesives. , a silicone-based pressure-sensitive adhesive, or the like. The adhesive may be emulsion type, solvent type or non-solvent type, and may be crosslinked or non-crosslinked. Among them, acrylic pressure-sensitive adhesives are preferable because they have excellent adhesive physical properties, optical properties, and the like.

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

Specifically, the pressure-sensitive adhesive is a pressure-sensitive adhesive composition containing a (meth)acrylic acid ester polymer (A), a cross-linking agent (B), and a colorant (C) (hereinafter “adhesive composition P”) is preferably crosslinked. Moreover, when using the said adhesive as an active-energy-ray-curable adhesive, it is preferable that the adhesive composition P contains an active-energy-ray-curable component (D) further.

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

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

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

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

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

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

The (meth)acrylic acid ester polymer (A) preferably contains a reactive group-containing monomer as a lower limit of 1% by mass or more, and preferably contains 5% by mass or more, as a monomer unit constituting the polymer. is more preferable, and it is particularly preferable to contain 10% by mass or more. Moreover, since the dispersibility of the colorant (C) in the adhesive tends to be better, it is more preferably contained in an amount of 12% by mass or more, and most preferably in an amount of 15% by mass or more. On the other hand, the (meth)acrylic acid ester polymer (A) preferably contains a reactive group-containing monomer as the upper limit of 35% by mass or less as a monomer unit constituting the polymer, and contains 30% by mass or less. More preferably, the content is particularly preferably 20% by mass or less. Moreover, since the dispersibility of the coloring agent (C) in the adhesive tends to be better, it is more preferable to contain 18% by mass or less. When the (meth)acrylic acid ester polymer (A) contains the reactive group-containing monomer in the above amount as a monomer unit, a good crosslinked structure is formed in the obtained pressure-sensitive adhesive, and desired cohesive strength is obtained. In addition, the dispersibility of the colorant (C) in the adhesive tends to be good, and the resulting adhesive has good reproducibility and uniformity of the optical properties described above, and has excellent design and visibility. It is an indication of sexuality. Furthermore, when the reactive group-containing monomer is a hydroxyl group-containing monomer, the content is particularly preferably 15% by mass or more. In this case, a predetermined amount of hydroxyl groups remain in the adhesive. Hydroxyl groups are hydrophilic groups, and if such hydrophilic groups are present in a predetermined amount in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, they will penetrate into the adhesive under such high temperature and high humidity conditions. As a result, whitening of the pressure-sensitive adhesive when returned to normal temperature and normal humidity is suppressed (excellent resistance to moist heat whitening).

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

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

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

The (meth)acrylic acid ester polymer (A) preferably contains 50% by mass or more, particularly 60% by mass or more, of (meth)acrylic acid alkyl ester as monomer units constituting the polymer. It is preferably contained in an amount of 65% by mass or more. When the lower limit of the content of the (meth)acrylic acid alkyl ester is the above, the (meth)acrylic acid ester polymer (A) can exhibit suitable adhesiveness. In addition, the dispersibility of the colorant (C) in the adhesive tends to be improved, and the (meth)acrylic acid ester polymer (A) does not impair the desired adhesiveness. As a result, the pressure-sensitive adhesive to be obtained exhibits suitable adhesiveness, exhibits good reproducibility and uniformity of the optical properties described above, and exhibits excellent design and visibility. On the other hand, the (meth)acrylic acid ester polymer (A) preferably contains 99% by mass or less, and preferably 95% by mass or less, of (meth)acrylic acid alkyl ester as the monomer units constituting the polymer. is more preferable, particularly preferably 90% by mass or less, and more preferably 85% by mass or less. When the upper limit of the content of the (meth)acrylic acid alkyl ester is the above, a suitable amount of another monomer component such as a reactive functional group-containing monomer is introduced into the (meth)acrylic acid ester polymer (A). be able to.

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

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

Specific examples of the alicyclic structure-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, adamantyl (meth)acrylate, isobornyl (meth)acrylate, (meth)acrylic Examples include dicyclopentenyl acid, dicyclopentenyloxyethyl (meth)acrylate, and among them, dicyclopentenyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 10), adamantyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 10) or isobornyl (meth)acrylate (the number of carbon atoms in the alicyclic structure: 7) is preferred, and isobornyl (meth)acrylate is particularly preferred. and isobornyl acrylate are preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the (meth)acrylic acid ester polymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, it preferably contains 1% by mass or more of the alicyclic structure-containing monomer. In particular, it is preferably contained in an amount of 4% by mass or more, more preferably 8% by mass or more. In addition, the (meth)acrylic acid ester polymer (A) preferably contains 30% by mass or less, particularly 22% by mass or less, of an alicyclic structure-containing monomer as a monomer unit constituting the polymer. is preferred, and it is more preferred to contain 14% by mass or less. When the content of the alicyclic structure-containing monomer is within the above range, the pressure-sensitive adhesive to be obtained has more excellent conformability to irregularities and more excellent adhesion to plastics.

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

Examples of monomers having a nitrogen-containing heterocyclic ring include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acryloylpyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloyl pyrrolidine, N-(meth)acryloylaziridine, aziridinylethyl (meth)acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylcarbazole, N-vinylphthalimide, etc. Among them, N-(meth)acryloylmorpholine, which exhibits superior adhesive strength, is preferred, and N-acryloylmorpholine is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

When the (meth)acrylic acid ester polymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, it preferably contains 1 mass% or more of the nitrogen atom-containing monomer, particularly 4 mass. % or more, more preferably 8 mass % or more. In addition, the (meth)acrylic acid ester polymer (A) preferably contains 20% by mass or less of the nitrogen atom-containing monomer, particularly 16% by mass or less, as a monomer unit constituting the polymer. It is preferably contained in an amount of 12% by mass or less. When the content of the nitrogen atom-containing monomer is within the above range, the resulting pressure-sensitive adhesive can sufficiently exhibit excellent adhesive strength to glass.

The (meth)acrylic acid ester polymer (A) may optionally contain other monomers as monomer units constituting the polymer. As other monomers, monomers containing no reactive functional group are preferred so as not to inhibit the above-described effects of the reactive functional group-containing monomer. Examples of such monomers include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, vinyl acetate, and styrene. These may be used alone or in combination of two or more.

The (meth)acrylate polymer (A) is preferably a linear polymer. By being a linear polymer, the entanglement of molecular chains is likely to occur, and improvement in cohesive strength can be expected, so that the storage elastic modulus, gel fraction, adhesive strength, etc. of the obtained adhesive are likely to be suitable. , the step followability under high-temperature and high-humidity conditions is excellent.

Moreover, the (meth)acrylate polymer (A) is preferably a solution polymer obtained by a solution polymerization method. Since it is a solution polymer, it is easy to obtain a high-molecular-weight polymer, and improvement in cohesive strength can be expected. It becomes excellent in step followability under high-temperature and high-humidity conditions.

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

The weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, further preferably 400,000 or more, as a lower limit. From the viewpoint of dispersibility of the colorant (C), it is more preferably 500,000 or more, and particularly preferably 700,000 or more. When the lower limit of the weight-average molecular weight of the (meth)acrylic acid ester polymer (A) is above, the storage elastic modulus, gel fraction, adhesive strength, etc. of the resulting pressure-sensitive adhesive tend to be suitable, and high-temperature, high-humidity The step followability under the conditions becomes more excellent. In addition, there is a tendency that the dispersibility of the colorant (C) in the pressure-sensitive adhesive can be improved. Therefore, the obtained pressure-sensitive adhesive has good reproducibility and uniformity of the optical properties described above, and is excellent in design. and visibility.

In addition, the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 2,000,000 or less, particularly preferably 1,500,000 or less, further preferably 1,000,000 or less as an upper limit. preferable. When the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is the above, the storage elastic modulus, gel fraction, adhesive strength, etc. of the obtained adhesive tend to be suitable, and the initial step Followability becomes more excellent. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

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

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

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

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

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

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.01 parts by mass or more, particularly 0.01 part by mass, based on 100 parts by mass of the (meth)acrylic acid ester polymer (A). 05 parts by mass or more, and more preferably 0.1 parts by mass or more. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.4 parts by mass or less. is preferred. When the content of the cross-linking agent (B) is within the above range, the resulting pressure-sensitive adhesive exhibits good cohesive strength, and easily satisfies desired storage modulus, gel fraction, adhesive strength, etc., and can be used under high temperature and high humidity conditions. It becomes excellent due to the ability to follow a step below.

(1-3) Colorant (C)
Colorant (C) is the colorant described above. Specific types are as described above.

The content of the colorant (C) with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A) is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, In particular, it is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more. The content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, particularly preferably 2 parts by mass or less, and further preferably 1 part by mass or less. . When the content of the colorant (C) is within the above range, the optical properties described above are easily satisfied.

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

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

Examples of polyfunctional acrylate monomers include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate. , neopentyl glycol adipate di(meth)acrylate, neopentyl glycol hydroxypivalate di(meth)acrylate, dicyclopentanyl di(meth)acrylate, tricyclodecanedimethanol (meth)acrylate, caprolactone-modified dicyclopentenyl di( meth)acrylate, ethylene oxide-modified phosphoric acid di(meth)acrylate, di(acryloxyethyl)isocyanurate, allylated cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2- Bifunctional type such as acryloyloxyethoxy)phenyl]fluorene; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate , propylene oxide-modified trimethylolpropane tri(meth)acrylate, tris(acryloxyethyl) isocyanurate, ε-caprolactone-modified tris-(2-(meth)acryloxyethyl) isocyanurate; diglycerin tetra ( Tetrafunctional type such as meth)acrylate and pentaerythritol tetra(meth)acrylate; Pentafunctional type such as propionic acid-modified dipentaerythritol penta(meth)acrylate; Dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa( Hexafunctional type such as meth)acrylate and the like can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type. From the viewpoint of compatibility with the (meth)acrylic acid ester polymer (A), the polyfunctional acrylate monomer preferably has a molecular weight of less than 1,000.

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

The content of the active energy ray-curable component (D) in the adhesive composition P is, from the viewpoint of making the step followability of the adhesive after active energy ray-curing more excellent under high-temperature and high-humidity conditions, The lower limit is preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, and preferably 4 parts by mass or more relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A). More preferred. On the other hand, the upper limit of the content is preferably 20 parts by mass or less, particularly preferably 12 parts by mass or less, and 8 parts by mass or less, from the viewpoint of the adhesive strength of the adhesive after curing with active energy rays. is more preferable.

(1-5) Photopolymerization initiator (E)
When ultraviolet rays are used as active energy rays for curing the adhesive composition P, the adhesive composition P preferably further contains a photopolymerization initiator (E). By containing the photopolymerization initiator (E) in this way, the active energy ray-curable component (D) can be efficiently polymerized, and the polymerization curing time and the irradiation dose of the active energy ray can be reduced. can.

Examples of such photoinitiators (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy -2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4- (methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylamino Benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4 ,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and the like. These may be used alone or in combination of two or more.

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

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

The mass ratio of the amount of photopolymerization initiator (E) to the amount of colorant (C) (photopolymerization initiator (E)/colorant (C)) is preferably 0.01 or more, particularly 0.01. It is preferably 1 or more, more preferably 0.2 or more. Also, the mass ratio is preferably 5 or less, particularly preferably 3 or less, and further preferably 1 or less. When the ratio of the amount of the photopolymerization initiator (E) to the amount of the colorant (D) is within the above range, the optical properties described above are satisfied, and the active energy ray curing provides suitable cohesive strength and adhesiveness. It becomes easy to obtain a pressure-sensitive adhesive, and it tends to be more excellent in step followability under high temperature and high humidity conditions.

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

The adhesive composition P preferably contains a silane coupling agent among the above. As a result, even if the adherend is a plastic plate or a glass member, the adhesion to the adherend is improved, and the step followability under high-temperature and high-humidity conditions is improved. .

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

Such silane coupling agents include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane and like silicon compounds containing polymerizable unsaturated groups, 3-glycidoxypropyltrimethoxysilane, 2-( Silicon compounds having an epoxy structure such as 3,4-epoxycyclohexyl)ethyltrimethoxysilane, mercapto group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane , 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino group-containing silicon compounds, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these, and an alkyl group-containing silicon compound such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. and condensates of. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent in the adhesive composition P is preferably 0.01 parts by mass or more, particularly 0.05 parts by mass, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A). It is preferably at least 0.1 part by mass, more preferably at least 0.1 part by mass. Also, the content is preferably 1 part by mass or less, particularly preferably 0.5 parts by mass or less, and further preferably 0.3 parts by mass or less.

(2) Preparation of adhesive composition The adhesive composition P is produced by producing a (meth) acrylic acid ester polymer (A), the obtained (meth) acrylic acid ester polymer (A), and a cross-linking agent ( It can be produced by mixing B) with a coloring agent (C), and optionally adding an active energy ray-curable component (D), a photopolymerization initiator (E), an additive, and the like.

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

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

Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di(2-ethoxyethyl)peroxy dicarbonate, t-butylperoxyneodecanoate, t-butylperoxybivalate, (3,5,5-trimethylhexanoyl)peroxide, dipropionylperoxide, diacetylperoxide and the like.

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

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

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

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

(3) Formation of Colored Adhesive Layer The colored adhesive layer 11 in the present embodiment is preferably made of an adhesive obtained by cross-linking (the coating layer of) the adhesive composition P. Crosslinking of the adhesive composition P can usually be performed by heat treatment. This heat treatment can also serve as a drying treatment for volatilizing the diluent solvent from the coating layer of the adhesive composition P applied to the desired object.

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

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

By the above heat treatment (and curing), the (meth)acrylate polymer (A) is sufficiently crosslinked via the crosslinking agent (B). The pressure-sensitive adhesive thus obtained easily satisfies desired storage elastic modulus, gel fraction, adhesive strength, etc., and is excellent in step conformability under high-temperature and high-humidity conditions.

(4) Physical Properties of Adhesive The adhesive in the present embodiment preferably has the following physical properties.
(4-1) Gel fraction The lower limit of the gel fraction of the adhesive in the present embodiment is preferably 20% or more, more preferably 40% or more, and particularly 50% or more. It is preferably 60% or more, and more preferably 60% or more. When the lower limit of the gel fraction of the pressure-sensitive adhesive is above, the pressure-sensitive adhesive has a high cohesive force, and the step followability under high-temperature and high-humidity conditions becomes more excellent. In addition, the upper limit of the gel fraction of the adhesive according to the present embodiment is preferably 100% or less, more preferably 90% or less, particularly preferably 80% or less, and further preferably 70%. % or less. When the upper limit of the gel fraction of the pressure-sensitive adhesive is above, the pressure-sensitive adhesive does not become too hard, and the initial conformability to unevenness and the conformability to unevenness under high-temperature and high-humidity conditions are both excellent. In addition, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent.

Here, the method for measuring the gel fraction of the pressure-sensitive adhesive is as shown in the test examples described later. Moreover, in the case of an active energy ray-curable adhesive, it is the gel fraction of the adhesive after active energy ray curing. In the case of an active energy ray-curable adhesive, the gel fraction of the adhesive before curing with an active energy ray is preferably 20 to 70% from the viewpoint of improving the initial step conformability, and 30%. ∼60% is particularly preferred, and 40 to 55% is more preferred.

(4-2) Storage Elastic Modulus The storage elastic modulus of the pressure-sensitive adhesive according to the present embodiment at 23° C. is preferably 0.001 MPa or more as a lower limit, more preferably 0.01 MPa or more, particularly 0 It is preferably 0.05 MPa or more, more preferably 0.1 MPa or more. By setting the lower limit of the storage elastic modulus to the above range, it becomes excellent in step followability under high-temperature and high-humidity conditions. The upper limit of the storage elastic modulus is preferably 2 MPa or less, more preferably 1 MPa or less, particularly preferably 0.8 MPa or less, and further preferably 0.4 MPa or less. , 0.2 MPa or less. By setting the upper limit of the storage elastic modulus to the above range, the initial conformability to irregularities and the conformability to irregularities under high-temperature and high-humidity conditions are excellent.

Here, the storage elastic modulus in this specification is a value measured by a torsional shear method at a measurement frequency of 1 Hz in accordance with JIS K7244-6. Specifically, it is as shown in the test examples described later. In the case of an active energy ray-curable adhesive, it is the storage elastic modulus of the adhesive after being cured with active energy rays. In the case of an active energy ray-curable adhesive, the storage elastic modulus of the adhesive before active energy ray curing is preferably 0.01 to 1 MPa from the viewpoint of improving the initial step conformability. It is particularly preferably 0.02 to 0.5 MPa, more preferably 0.04 to 0.1 MPa.

(5) Thickness of Colored Adhesive Layer The lower limit of the thickness of the colored adhesive layer 11 is preferably 1 μm or more, more preferably 2 μm or more, and particularly preferably 4 μm or more. When the lower limit of the thickness of the colored pressure-sensitive adhesive layer 11 is within the above range, the aforementioned optical properties are easily satisfied and the desired adhesive strength is easily exhibited in relation to the content of the colorant (C). In addition, from the viewpoint of facilitating excellent step conformability, the lower limit is preferably 10 μm or more, more preferably 20 μm or more, particularly preferably 50 μm or more, and 80 μm or more. is more preferred.

On the other hand, the upper limit of the thickness of the colored pressure-sensitive adhesive layer 11 is preferably 500 μm or less, more preferably 300 μm or less, particularly preferably 200 μm or less, further preferably 150 μm or less. . When the upper limit value of the thickness of the colored pressure-sensitive adhesive layer 11 is within the above range, workability is improved, and defects in appearance such as impression marks are less likely to occur. Furthermore, the above-described optical properties are easily satisfied in relation to the content of the colorant (C). In addition, the colored adhesive layer 11 may be formed as a single layer, or may be formed by laminating a plurality of layers.

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

Examples of the release sheets 12a and 12b include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene. Terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine A resin film or the like is used. Crosslinked films of these are also used. Furthermore, a laminated film of these may be used.

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

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

2. Physical properties (adhesive strength)
The adhesive strength of the colored adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 1 N/25 mm or more, more preferably 2 N/25 mm or more, and 4 N/25 mm or more as a lower limit. It is particularly preferable, and more preferably 8 N/25 mm or more. When the lower limit of the adhesive strength is above, the step followability under high temperature and high humidity conditions becomes more excellent. Further, the upper limit of the adhesive strength of the colored adhesive sheet 1 according to the present embodiment to soda lime glass is preferably 80 N/25 mm or less, more preferably 50 N/25 mm or less, and 30 N/25 mm or less. is particularly preferred. When the upper limit of the adhesive strength is above, good reworkability can be obtained, and in the event of a lamination error, it becomes possible to reuse display body constituent members, especially expensive display body constituent members.

Here, the adhesive strength in this specification basically refers to the adhesive strength measured by the 180 degree peeling method according to JIS Z0237: 2009, but the measurement sample has a width of 25 mm and a length of 100 mm. It is attached to an adherend, pressurized at 0.5 MPa and 50° C. for 20 minutes, then left under normal pressure, 23° C. and 50% RH for 24 hours, and then measured at a peel rate of 300 mm/min. shall be In the case of an active energy ray-curable pressure-sensitive adhesive, it is the adhesive strength of the colored pressure-sensitive adhesive layer cured with active energy ray after sticking to the adherend. In the case of an active energy ray-curable adhesive, the adhesive strength of the adhesive before active energy ray curing is preferably 1 to 80 N/25 mm from the viewpoint of adhesion to the adherend and reworkability. , 2 to 50 N/25 mm, more preferably 4 to 30 N/25 mm.

3. Production of Colored Adhesive Sheet As an example of production of the colored adhesive sheet 1, the release surface of one of the release sheets 12a (or 12b) is coated with the coating solution of the above-mentioned adhesive composition P, and heat treatment is performed to make it adhesive. After the composition P is thermally crosslinked to form a coating layer, the release surface of the other release sheet 12b (or 12a) is superposed on the coating layer. If a curing period is required, a curing period is provided, and if the curing period is not required, the coating layer becomes the colored adhesive layer 11 as it is. As a result, the colored adhesive sheet 1 is obtained. The conditions for heat treatment and curing are as described above.

As another production example of the colored adhesive sheet 1, the coating solution of the adhesive composition P is applied to the release surface of one release sheet 12a, and heat treatment is performed to thermally crosslink the adhesive composition P, A coating layer is formed to obtain a release sheet 12a with a coating layer. Further, the coating solution of the adhesive composition P is applied to the release surface of the other release sheet 12b, and heat treatment is performed to thermally crosslink the adhesive composition P to form a coating layer. to obtain a release sheet 12b. Then, the release sheet 12a with the coating layer and the release sheet 12b with the coating layer are pasted together so that both coating layers are in contact with each other. Here, a plurality of release sheets with coating layers may be prepared, and a desired number of the coating layers may be pasted together. If a curing period is required, the curing period is set, and if the curing period is not required, the laminated coating layer becomes the colored adhesive layer 11 as it is. As a result, the colored adhesive sheet 1 is obtained. According to this production example, even when the colored pressure-sensitive adhesive layer 11 is thick, it is possible to produce stably.

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

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

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

At least one of the first display body-constituting member 21 and the second display body-constituting member 22 may have a step at least on the side bonded with the colored pressure-sensitive adhesive layer 11 . In the present embodiment shown in FIG. 2, the first display member constituting member 21 has steps such as the printed layer 3 on the surface on the colored adhesive layer 11 side.

The colored adhesive layer 11 in the display body 2 is the colored adhesive layer 11 of the colored adhesive sheet 1 described above.

Examples of the display 2 include a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, and the like, and may be a touch panel.

The first display member constituting member 21 is preferably a protective panel made of a glass plate, a plastic plate or the like, or a laminated body including them. In this case, the printed layer 3 is generally formed in a frame shape on the side of the colored adhesive layer 11 of the first display member constituting member 21 .

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

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

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

The second display body constituent member 22 includes an optical member to be attached to the first display body constituent member 21, a display body module (for example, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electroluminescence (organic EL) module, etc.), an optical member as part of a display module, or a laminate including a display module.

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

The material constituting the printing layer 3 is not particularly limited, and known materials for printing are used. The lower limit of the thickness of the printing layer 3, that is, the height of the step, is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, and most preferably 10 μm or more. preferable. When the lower limit value is equal to or higher than the above, it is possible to sufficiently secure the concealability such as making the electric wiring invisible from the viewer side. The upper limit is preferably 50 μm or less, more preferably 35 μm or less, particularly preferably 25 μm or less, and even more preferably 20 μm or less. When the upper limit value is equal to or less than the above, it is possible to prevent the colored adhesive layer 11 from deteriorating in conformability to unevenness of the printed layer 3 .

In order to manufacture the display body 2, as an example, one release sheet 12a of the colored adhesive sheet 1 is peeled off, and the exposed colored adhesive layer 11 of the colored adhesive sheet 1 is transferred to the first display body constituent member 21. is laminated on the side on which the printed layer 3 is present.

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

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

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

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

Here, as shown in FIG. 3, it is preferable that the display body 2 according to the present embodiment has a frame member 4 at the peripheral edge portion of the display body 2 . This frame material 4 is preferably black. Further, the preferred ranges of the lightness L*, chromaticity a*, and chromaticity b* defined by the CIE1976 L*a*b* color system as the color of the frame member 4 are as described above for the color of the peripheral member. is. The frame member 4 having such a color tends to be visually recognized by the human eye as a frame member with a high-grade appearance. In addition, since the frame material 4 has the above color, the colored pressure-sensitive adhesive layer 11 according to the present embodiment has an increased sense of unity with the frame material 4, and has better appearance harmony.

In the above-described display 2, due to the physical properties of the colored adhesive layer 11 described above, whitishness at the time of extinguishing is suppressed, and the design is improved. As a result, for example, a sense of unity with the black frame member 4 is imparted, resulting in excellent appearance harmony. Further, the display body 2 ensures visibility as a display body.

Furthermore, in the display body 2, when the colored pressure-sensitive adhesive layer 11 is formed from the pressure-sensitive adhesive composition P, the colored pressure-sensitive adhesive layer 11 has excellent step conformability under high-temperature and high-humidity conditions. Even when the body 2 is placed under high-temperature and high-humidity conditions (eg, 85° C., 85% RH), the occurrence of floating, peeling, etc. near the step is suppressed.

The step followability can be determined using the step followability rate (%) as an index. The colored pressure-sensitive adhesive layer 11 has a level difference follow-up rate (%) represented by the following formula, which is preferably 10% or more as a lower limit, more preferably 20% or more, and particularly 40% or more. is preferred, and more preferably 60% or more. Moreover, the upper limit of the step follow-up rate is not particularly limited, but is usually preferably 80% or less, and particularly preferably 70% or less.
Level difference follow-up rate (%) = {(height of level difference maintained in a buried state without air bubbles, floating, peeling, etc. after the predetermined durability test (μm))/(thickness of colored adhesive layer)}×100
The test method for the step followability rate is as shown in the test examples described later.

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

For example, one or both of the release sheets 12a and 12b in the colored adhesive sheet 1 may be omitted, or a desired optical member may be laminated instead of the release sheets 12a and/or 12b. Further, the first display member constituting member 21 may not have steps. Furthermore, not only the first display member forming member 21 but also the second display member forming member 22 may have a step on the colored adhesive layer 11 side.

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

[Example 1]
1. Preparation of (meth)acrylic acid ester polymer 70 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of methyl methacrylate, and 15 parts by mass of 2-hydroxyethyl acrylate are copolymerized by a solution polymerization method to obtain a (meth)acrylic ester polymer. An acid ester polymer (A) was prepared. When the molecular weight of this (meth)acrylic acid ester polymer (A) was measured by the method described later, it was found to have a weight average molecular weight (Mw) of 800,000.

2. Preparation of adhesive composition 100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the above step 1 (solid content conversion value; the same applies hereinafter), and a trimethylolpropane-modified trimethylolpropane-modified trimethylolpropane Diisocyanate (manufactured by Toyochem Co., Ltd., product name "BHS8515") 0.2 parts by mass, carbon black-based black pigment (C1) 0.4 parts by mass as a coloring agent (C), 3- as a silane coupling agent 0.2 parts by mass of glycidoxypropyltrimethoxysilane was mixed, thoroughly stirred, and diluted with methyl ethyl ketone to obtain a coating solution of the adhesive composition.

Here, Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth)acrylic acid ester polymer (A) is 100 parts by mass (solid content conversion value). Details of abbreviations and the like in Table 1 are as follows.
[(Meth) acrylic ester polymer (A)]
2EHA: 2-ethylhexyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate IBXA: isobornyl acrylate ACMO: N-acryloylmorpholine BA: n-butyl acrylate AA: acrylic acid
[Colorant (C)]
C1 to C6: carbon black-based black pigments having physical properties shown in Table 2

3. Production of colored adhesive sheet The coating solution of the adhesive composition obtained in the above step 2 is applied to a polyethylene terephthalate film on one side of which is treated with a silicone-based release agent to release a heavy release type release sheet (manufactured by Lintec, product name "SP- PET752150") was coated with a knife coater and then heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 50 μm). Also, the coating solution of the adhesive composition obtained in the above step 2 was applied to a light release type release sheet (Lintec Co., Ltd., product name "SP-PET381130") obtained by releasing one side of a polyethylene terephthalate film with a silicone release agent. ) was coated with a knife coater and then heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 50 μm).

Next, the heavy-release release sheet with the coating layer obtained above and the light-release release sheet with the coating layer obtained above were laminated so that both coating layers were in contact with each other, and the temperature was maintained at 23°C. , and 50% RH for 7 days to prepare a colored adhesive sheet having a structure of heavy release release sheet/colored adhesive layer (thickness: 100 μm)/light release release sheet.

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

[Examples 2 to 8, Comparative Examples 1 to 2]
Type and ratio of each monomer constituting the (meth)acrylic acid ester polymer (A), weight average molecular weight (Mw) of the (meth)acrylic acid ester polymer (A), type and amount of the colorant (C) , the amount of the silane coupling agent, and the thickness of the colored adhesive layer were changed as shown in Table 1, to produce a colored adhesive sheet in the same manner as in Example 1. However, in Example 5, ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK Ester A-9300”) was used as the active energy ray-curable component (D). -1CL") 5.0 parts by mass, and 0.5 parts by mass of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide as a photopolymerization initiator (E) are further added to obtain an active energy ray-curable Got the adhesive. In Comparative Example 1, no colorant (C) is used, but for the sake of convenience, the terms "colored adhesive layer" and "colored adhesive sheet" are used.

The colored pressure-sensitive adhesive sheets of Examples 3-8 and Comparative Examples 1-2 were produced as follows. A coating solution of an adhesive composition prepared in the same manner as in Example 1 was applied to a heavy release type release sheet (manufactured by Lintec, product name "SP-PET752150") obtained by releasing one side of a polyethylene terephthalate film with a silicone release agent. was applied to the release-treated surface of No. 2 using a knife coater, and then heat-treated at 90° C. for 1 minute to form a coating layer. A light release release sheet (manufactured by Lintec Corporation, product name "SP-PET381130 ”) and cured for 7 days under the conditions of 23 ° C. and 50% RH to obtain a coloring consisting of a heavy release release sheet / colored adhesive layer / light release release sheet. An adhesive sheet was produced.

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

[Test Example 1] (Measurement of haze value of colorant diluted solution)
A solution obtained by diluting C1 to C6 colorants 10,000 times with ethyl acetate is measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000", optical path length 10 mm) according to JIS K7136:2000. haze value (%) was measured. From the measured values, the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, the average haze that is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, and the 5 nm pitch in the wavelength region of 380 nm to 780 nm. The standard deviation of the haze value at each wavelength was calculated. Each result is shown in Table 2.

[Test Example 2] (Measurement of gel fraction)
The colored adhesive sheets obtained in Examples and Comparative Examples were cut into a size of 80 mm × 80 mm, the colored adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed with a precision balance, By subtracting the mass of the mesh alone, the mass of the pressure-sensitive adhesive alone was calculated. Let the mass at this time be M1.

Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23° C.) for 24 hours. After that, the pressure-sensitive adhesive was taken out and air-dried for 24 hours in an environment of a temperature of 23° C. and a relative humidity of 50%, and further dried in an oven of 80° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M2. A gel fraction (%) is represented by (M2/M1)×100. Table 3 shows the results.

In addition, for the colored adhesive sheet of Example 5, a plastic plate (manufactured by Mitsubishi Gas Chemical Co., Ltd., product name: "Iupilon sheet MR58U", thickness: 0.7 mm, containing ultraviolet absorber) was superimposed, and active energy rays were irradiated under the following conditions through the plastic plate to cure the colored adhesive layer. For the adhesive of the colored adhesive layer after curing, the gel fraction (after UV) was derived in the same manner as described above.

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

[Test Example 3] (Measurement of storage elastic modulus)
The release sheets were peeled off from the colored pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples, and a plurality of colored pressure-sensitive adhesive layers were laminated to a thickness of 3 mm. A cylinder with a diameter of 8 mm (height: 3 mm) was punched out from the laminate of the colored pressure-sensitive adhesive layers thus obtained, and this was used as a sample.

The storage modulus (MPa) of the above sample was measured according to JIS K7244-6 by the torsional shear method using a viscoelasticity measuring device (manufactured by Physica, product name "MCR300") under the following conditions. Table 3 shows the results.
Measurement frequency: 1Hz
Measurement temperature: 23°C

For the colored pressure-sensitive adhesive sheet of Example 5, the colored pressure-sensitive adhesive layer was cured by irradiating the active energy ray in the same manner as in Test Example 2, and the cured colored pressure-sensitive adhesive layer was also treated as described above. Storage modulus (after UV) was measured.

[Test Example 4] (Measurement of haze value)
For the colored adhesive layers of the colored adhesive sheets obtained in Examples and Comparative Examples, the haze value was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SH-7000") according to JIS K7136:2000. (%) was measured. Table 3 shows the obtained total light haze values (%). Also, from the measured values, the average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, and 5 nm in the wavelength range of 380 nm to 780 nm. The standard deviation of the haze value at each pitch wavelength was calculated.

The colored pressure-sensitive adhesive sheet of Example 5 was irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored pressure-sensitive adhesive layer. Total light haze values (after UV) were measured. Then, from the measured values, the average haze (after UV), which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, and the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm (after UV). , and the standard deviation (after UV) of the haze value at each wavelength with a pitch of 5 nm in the wavelength region of 380 nm to 780 nm. Each result is shown in Table 3.

[Test Example 5] (Measurement of total light transmittance)
The colored pressure-sensitive adhesive layers of the colored pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were attached to glass to prepare samples for measurement. After performing background measurement on glass, the above measurement sample was measured according to JIS K7361-1: 1997 with a haze meter (manufactured by Nippon Denshoku Industries, product name "SH-7000"). Transmittance (%) was measured. The colored pressure-sensitive adhesive sheet of Example 5 was irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored pressure-sensitive adhesive layer. Light transmittance (after UV) was measured. Table 3 shows the results.

[Test Example 6] (Measurement of L*a*b*)
The colored pressure-sensitive adhesive layers of the colored pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were analyzed using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name: "SQ2000"), and CIE1976L*a*b* was measured. Lightness L*, chromaticity a* and chromaticity b* defined by the color system were measured. The colored pressure-sensitive adhesive sheet of Example 5 was irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored pressure-sensitive adhesive layer. L* (after UV), chromaticity a* (after UV) and chromaticity b* (after UV) were measured. Table 3 shows the results.

[Test Example 7] (Measurement of adhesive strength)
The light-release type release sheet was peeled off from the colored adhesive sheets obtained in Examples and Comparative Examples, and the exposed colored adhesive layer was covered with a polyethylene terephthalate (PET) film having an easy-adhesion layer (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 100 μm) to obtain a laminate of release sheet/colored adhesive layer/PET film. The laminate thus obtained was cut into a piece having a width of 25 mm and a length of 100 mm, which was used as a sample.

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

For the colored pressure-sensitive adhesive sheet of Example 5, the colored pressure-sensitive adhesive layer was applied to the soda lime glass in the same manner as described above, autoclaved, and left under the conditions of 23°C and 50% RH for 24 hours. , was irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored pressure-sensitive adhesive layer. The adhesive strength (after UV) of the cured colored adhesive layer was measured in the same manner as described above.

[Test Example 8] (Measurement of step follow-up rate)
On the surface of a glass plate (manufactured by NSG Precision Co., Ltd., product name “Corning Glass Eagle XG”, length 90 mm × width 50 mm × thickness 0.5 mm), ultraviolet curable ink (manufactured by Teikoku Ink Co., Ltd., product name “POS-911 ink”) ) was screen-printed into a picture frame (outer shape: 90 mm long, 50 mm wide, 5 mm wide). Next, ultraviolet rays are irradiated (80 W/cm ² , 2 metal halide lamps, lamp height 15 cm, belt speed 10 to 15 m/min) to cure the printed UV curable ink, and the height of the step due to printing A stepped glass plate having a thickness of any one of 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 50 μm, 60 μm and 70 μm was produced.

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

The resulting sample for evaluation was autoclaved under conditions of 50° C. and 0.5 MPa for 30 minutes, and then allowed to stand at normal pressure, 23° C. and 50% RH for 24 hours. Then, it was stored under high temperature and high humidity conditions of 85° C. and 85% RH for 72 hours (durability test), and then the step followability was evaluated. The level difference followability is judged by whether or not the printed level difference is completely filled with the colored adhesive layer. It is determined that the vehicle could not follow the step. Here, the step followability was evaluated as a step follow-up rate (%) represented by the following formula. Table 3 shows the results.
Level difference follow-up rate (%) = {(height of level difference maintained in buried state without air bubbles, floating, peeling, etc. after endurance test (μm))/(thickness of colored adhesive layer)}×100

For the colored pressure-sensitive adhesive sheet of Example 5, a colored pressure-sensitive adhesive layer having a thickness of 25 µm was prepared, and an evaluation sample obtained in the same manner as described above was subjected to autoclave treatment and then heated at 23°C and 50°C. % RH for 24 hours, and then irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored pressure-sensitive adhesive layer. For the colored pressure-sensitive adhesive layer after curing, the step followability (after UV) was measured in the same manner as described above.

[Test Example 9] (Evaluation of Designability)
The colored adhesive sheets obtained in Examples and Comparative Examples were cut into a length of 70 mm x width of 70 mm, and the colored adhesive layer of the colored adhesive sheet was covered with two sheets of soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd., length of 70 mm x width of 70 mm). x thickness 1.1 mm), and this was used as a sample. The colored adhesive sheet of Example 5 was irradiated with active energy rays in the same manner as in Test Example 2 to cure the colored adhesive layer, which was used as a sample.

The obtained sample was installed immediately before a display (manufactured by Fujitsu Ltd., product name “LITEBOOK A574/H”, size 15.6 inches, resolution 1366×768) in the off state. At this time, the sample was placed so that the peripheral portion of the sample and the frame material of the display were adjacent to each other. Then, under a three-wavelength fluorescent lamp (distance from the fluorescent lamp: 200 cm), the color of the sample (darkness/whitishness) was visually judged, and the design related to the color of the screen was determined according to the following criteria. evaluated the sex. Table 3 shows the results.
⊚: Deep blackness even under fluorescent light reflection.
◯: Deep blackness is observed if there is no fluorescent light reflection.
x: The whole looks whitish.

Also, the appearance of the boundary between the sample portion and the frame material of the display was visually judged, and the designability related to the seamlessness was evaluated according to the following criteria. Table 3 shows the results.
A: Boundaries cannot be visually recognized.
◯: The boundary is slightly visible but inconspicuous.
x: A boundary can be visually recognized clearly.

The color of the frame material of the display (CIE1976 L*a*b* color system) was measured using a spectrophotometer (manufactured by BYK, product name "Spectro-Guide"), and L* : 19.7, a*: -0.3, b*: -1.5.

[Test Example 10] (Evaluation of visibility)
A sample prepared in the same manner as in Test Example 9 was placed immediately before a lit display (manufactured by Fujitsu Limited, product name “LITEBOOK A574/H”, size 15.6 inches, resolution 1366×768). At this time, an ARIB multi-format color bar was displayed on the display. Then, under a three-wavelength fluorescent lamp (distance from the fluorescent lamp: 200 cm), visually judge how the display looks through the sample from the front and diagonally (45 ° angle) with respect to the sample. Visibility (wide-angle visibility) was evaluated by . Table 3 shows the results.
⊚: There is no difference between the appearance from the front and the appearance from an oblique angle.
◯: Compared to the front view, the view from the oblique direction is darker, but the color does not change.
x: The color tone changes depending on how it is viewed from the front and how it is viewed from an oblique direction.

In each example, the screen was bright when viewed from the front, and therefore the visibility of the image due to the brightness of the screen was good.

As can be seen from Table 3, those using the colored adhesive sheets obtained in Examples have design properties (especially design properties related to screen color) and visibility (especially wide-angle visibility and screen brightness). visibility) was excellent. In addition, the colored pressure-sensitive adhesive sheets obtained in Examples were also excellent in conformability to unevenness.

The colored pressure-sensitive adhesive sheet of the present invention is suitable for, for example, bonding between display body constituent members in a display body having a black frame material, particularly bonding between a protective panel having a step and a desired display body constituent member. can be used.

DESCRIPTION OF SYMBOLS 1... Colored adhesive sheet 11... Colored adhesive layer 12a, 12b... Release sheet 2... Display body 21... First display body constituent member 22... Second display body constituent member 3... Printed layer 4... Frame material

Claims (10)

A colored adhesive sheet comprising a colored adhesive layer made of an adhesive containing a coloring agent for bonding one display body constituent member and another display body constituent member,
The average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, of the colored pressure-sensitive adhesive layer is 1% or more and 45% or less,
A colored pressure-sensitive adhesive sheet, wherein the lightness L* defined by the CIE1976 L*a*b* color system of the colored pressure-sensitive adhesive layer is 92 or less. 2. The colored pressure-sensitive adhesive sheet according to claim 1, wherein the difference between the haze value of the colored pressure-sensitive adhesive layer at a wavelength of 780 nm and the haze value at a wavelength of 380 nm is 15 points or less. 3. The colored pressure-sensitive adhesive sheet according to claim 1, wherein the standard deviation of the haze value of the colored pressure-sensitive adhesive layer at each wavelength of 5 nm pitch in the wavelength region of 380 nm to 780 nm is 5 or less. The colored adhesive layer has a total light transmittance of 10% or more and less than 95%,
4. The colored pressure-sensitive adhesive layer according to any one of claims 1 to 3, wherein chromaticity a* and chromaticity b* defined by the CIE1976 L*a*b* color system are -7 to 7, respectively. 1. The colored pressure-sensitive adhesive sheet according to item 1. The average haze, which is the average value of the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm, of a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is 1% or more and 60% or less. The colored adhesive sheet according to any one of claims 1 to 4. 6. The method according to any one of claims 1 to 5, wherein the difference between the haze value at a wavelength of 780 nm and the haze value at a wavelength of 380 nm in a liquid obtained by diluting the coloring agent 10,000 times with ethyl acetate is 30 points or less. The colored pressure-sensitive adhesive sheet according to any one of items. The colored pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the coloring agent is a black pigment. The colored pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive. The colored adhesive sheet according to any one of claims 1 to 8, wherein the adhesive contains a silane coupling agent. 1 to 1, wherein the adhesive is a crosslinked adhesive composition containing a (meth)acrylic acid ester polymer (A), a crosslinking agent (B) and a colorant (C). 10. The colored adhesive sheet according to any one of 9.

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