JP7233405B2 - PSA SHEET, DISPLAY, AND METHOD FOR MANUFACTURING DISPLAY - Google Patents

Description

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

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 an 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 pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer for bonding one display body constituent member and another display body constituent member, The adhesive layer comprises an active energy ray-curable adhesive containing a coloring agent, the adhesive layer has a total light transmittance of 3% or more, and the adhesive layer complies with the CIE1976 L*a*b* color system. A pressure-sensitive adhesive sheet characterized by having a lightness L* of 95 or less (Invention 1).

According to the above invention (invention 1), when applied to a display body, the designability (as an example, appearance harmony) of the display body can be improved. For example, when the display body is turned off, it is possible to give the display body a sense of unity with the peripheral member, for example, the black frame material, thereby enhancing the appearance harmony and giving a sense of quality. becomes. Further, by having the above total light transmittance, visibility as a display can be ensured.

In the above invention (invention 1), the pressure-sensitive adhesive layer preferably has a haze value of 0.01% or more and 80% or less (invention 2).

In the above inventions (inventions 1 and 2), the coloring agent is preferably a black pigment or dye (invention 3).

In the above inventions (Inventions 1 to 3), when the content of the colorant in the pressure-sensitive adhesive is X% by mass and the thickness of the pressure-sensitive adhesive layer is Z μm, the following formula (I) can be satisfied. Preferred (Invention 4).
5≦X×Z<300 (I)

In the above inventions (Inventions 1 to 4), the content of the coloring agent in the active energy ray-curable adhesive is preferably 0.01% by mass or more and 2.0% by mass or less (Invention 5 ).

In the above inventions (inventions 1 to 5), the adhesive is preferably an acrylic adhesive (invention 6).

In the above inventions (inventions 1 to 6), the adhesive comprises a (meth)acrylic acid ester polymer (A), a cross-linking agent (B), an active energy ray-curable component (C) and a colorant (D). It is preferable that the contained adhesive composition is crosslinked (Invention 7).

In the above inventions (inventions 1 to 7), it is preferable to include two release sheets and the adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets (invention 8).

Secondly, the present invention provides a display body constituent member, another display body constituent member, and a post-curing pressure-sensitive adhesive layer for adhering the one display body constituent member and the other display body constituent member to each other. wherein the post-curing pressure-sensitive adhesive layer is a post-curing pressure-sensitive adhesive layer obtained by curing the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (Inventions 1 to 8) with an active energy ray. (Invention 9).

In the above invention (invention 9), at least one of the one display body-constituting member and the other display body-constituting member has at least a step on the side bonded by the post-curing pressure-sensitive adhesive layer. Preferred (Invention 10).

In the above inventions (Inventions 9 and 10), it is preferable to have a black frame material (Invention 11).

The third aspect of the present invention is to prepare a laminate by laminating one display body constituent member and another display body constituent member via the adhesive layer of the adhesive sheet (inventions 1 to 8), There is provided a method for manufacturing a display, comprising irradiating the adhesive layer of the laminate with an active energy ray and curing the adhesive layer to form a cured adhesive layer (Invention 12). .

According to the 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 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.
[Adhesive sheet]
A pressure-sensitive adhesive sheet according to an embodiment of the present invention includes a pressure-sensitive adhesive layer for bonding one display body-constituting member and another display body-constituting member, and preferably one side of the pressure-sensitive adhesive layer Alternatively, release sheets are laminated on both sides. The display body and display body constituent members will be described later.

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

1. Each member 1-1. Adhesive Layer The adhesive layer 11 of the adhesive sheet 1 according to this embodiment is made of an active energy ray-curable adhesive containing a coloring agent. The total light transmittance of the adhesive layer 11 (value measured according to JIS K7361-1: 1997) is 3% or more, and is defined by the CIE1976L*a*b* color system of the adhesive layer 11. The lightness L* used is 95 or less. Incidentally, the method for measuring the lightness L* in this specification is as shown in the test examples described later.

The pressure-sensitive adhesive layer 11 that satisfies the above physical properties can improve the design properties (as an example, appearance harmony) of the display body when applied to the display body when the display body is turned off. Specifically, it is possible to give the display body a sense of unity with a peripheral member, for example, a black frame member, thereby enhancing appearance harmony and giving a high-class feeling. Further, when the total light transmittance is 3% or more, visibility as a display can be ensured.

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 95, 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 pressure-sensitive adhesive sheet 1 according to this embodiment can be suitably used for a display body having a peripheral member with the above color.

From the viewpoint of visibility as a display, the total light transmittance of the adhesive layer 11 is 3% or more, preferably 10% or more, particularly preferably 25% or more, and further preferably 50% or more. is. Although the upper limit of the total light transmittance is not particularly limited, it is usually 100% or less, and considering the relationship with the lightness L*, it is preferably 98% or less, particularly preferably 95% or less. , and more preferably 90% or less.

In addition, from the viewpoint of improving the design property by appearance harmony, the lightness L* of the pressure-sensitive adhesive layer 11 is 95 or less, preferably 92 or less, particularly preferably 89 or less, and further preferably 86 or less. . On the other hand, from the viewpoint of designability improvement by appearance harmony and visibility of the display, the lower limit value of the lightness L* is preferably 10 or more, more preferably 20 or more, and particularly 30 or more. more preferably 40 or more, and most preferably 55 or more.

Furthermore, the chromaticity a* of the pressure-sensitive adhesive layer 11 defined by the CIE1976 L*a*b* color system is preferably −40 or more, more preferably −30 or more, and particularly −20 or more. It is preferably -15 or more, and most preferably -10 or more. The chromaticity a* is preferably 40 or less, more preferably 30 or less, particularly preferably 20 or less, further preferably 15 or less, and 10 or less. is most preferred. When the chromaticity a* is within the above range, the designability, especially the designability (especially the appearance harmony) of the in-vehicle display body is further improved.

In addition, the chromaticity b* of the pressure-sensitive adhesive layer 11 defined by the CIE1976 L*a*b* color system is preferably −40 or more, more preferably −30 or more, and particularly −20 or more. It is preferably -15 or more, and most preferably -10 or more. The chromaticity b* is preferably 40 or less, more preferably 30 or less, particularly preferably 20 or less, further preferably 15 or less, and 10 or less. is most preferred. When the chromaticity b* is within the above range, the designability, particularly the designability (especially the appearance harmony) of the in-vehicle display body is further improved.

The haze value of the pressure-sensitive adhesive layer 11 is usually 0% or more, and when the colorant in the pressure-sensitive adhesive layer 11 is a dye, it is preferably 0.01% or more, and preferably 0.05% or more. is more preferable, and 0.1% or more is particularly preferable. Further, when the colorant in the adhesive layer 11 is a pigment, the haze value of the adhesive layer 11 is preferably 0.1% or more, more preferably 1% or more, and 6% or more. 12% or more is most preferable. When the haze value of the pressure-sensitive adhesive layer 11 has the above lower limit, it becomes easier to impart a sense of unity with the surrounding member (for example, frame member) to the obtained display. On the other hand, the haze value of the adhesive layer 11 is preferably 80% or less, more preferably 70% or less, particularly preferably 60% or less, and further preferably 50% or less. Most preferably, it is 40% or less. By setting the upper limit of the haze value of the pressure-sensitive adhesive layer 11 to the above range, the total light transmittance tends to fall within the above range, and the obtained display body has a sense of unity with the peripheral member (for example, the frame member). Easier to give. The haze value in this specification is a value measured according to JIS K7136:2000.

The total light transmittance, haze value, lightness L*, chromaticity a*, and chromaticity b* of the adhesive layer 11 were obtained by curing the adhesive layer 11 by irradiating the active energy ray and curing the adhesive layer. After that, not much change.

The total light transmittance and lightness L* (further chromaticity a* and b*, and haze value) are determined by appropriately selecting the type and content of the colorant contained in the adhesive constituting the adhesive layer 11. It is possible to achieve

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 (especially blister resistance) 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 pressure-sensitive adhesive layer 11 .

Among the above-mentioned colorants, carbon black, nigrosine-based black dye and chromic acid are used from the viewpoint of easily achieving the above-mentioned total light transmittance and lightness L* (further haze value) and easily producing a sense of unity with peripheral members. Salt-based black dyes are preferred. The surface of the carbon black may or may not be subjected to a predetermined treatment (for example, a solvent-affinity treatment).

The content X mass % of the coloring agent in the pressure-sensitive adhesive preferably satisfies the following formula (I) when the thickness of the pressure-sensitive adhesive layer 11 is Z μm.
5≦X×Z<300 (I)
When the value of X×Z is within the above range, the above-mentioned total light transmittance and lightness L* (further haze value) can be easily achieved. The thickness of the pressure-sensitive adhesive layer 11 in this specification is a value measured according to JIS K7130.

From the above viewpoint, the lower limit of X×Z is preferably 8 or more, particularly preferably 10 or more, and further preferably 15 or more. In addition, the upper limit of X×Z is preferably 250 or less, more preferably 150 or less, particularly preferably 100 or less, and further preferably 60 or less from the viewpoint of blister resistance. is preferred, and 30 or less is most preferred.

In order for the value of X×Z to easily fall within the above range, the content (X mass %) of the colorant in the pressure-sensitive adhesive is preferably 0.01 mass % or more as a lower limit, and 0.01 mass % or more. It is more preferably 05% by mass or more, particularly preferably 0.1% by mass or more, and further preferably 0.12% by mass or more. The upper limit of the content of the coloring agent (X mass %) is preferably 2.0 mass % or less, more preferably 1.0 mass % or less, and particularly 0.5 mass % or less. and more preferably 0.2% by mass or less.

The type of adhesive constituting the adhesive layer 11 of the adhesive sheet 1 according to the present embodiment is not particularly limited as long as it is active energy ray-curable. ) and the like, an active energy ray-curable acrylic pressure-sensitive adhesive is preferred. The acrylic pressure-sensitive adhesive may be an emulsion type, a solvent type or a non-solvent type, and may be either a crosslinked type or a non-crosslinked type. Among them, an active energy ray-curable cross-linking type acrylic pressure-sensitive adhesive is preferable.

The pressure-sensitive adhesive is particularly a pressure-sensitive adhesive composition containing a (meth)acrylic acid ester polymer (A), a cross-linking agent (B), an active energy ray-curable component (C), and a colorant (D). It is preferable that the product (hereinafter sometimes referred to as "adhesive composition P") is crosslinked. Colorant (D) 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 and blister resistance 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, hydroxyl group-containing monomers and carboxy group-containing monomers, which are excellent in reactivity with the cross-linking agent (B), are preferred, and hydroxyl group-containing monomers, which have little adverse effect on adherends, are particularly preferred.

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, particularly 5% by mass or more, as a monomer unit constituting the polymer. more preferably 8% by mass or more, and particularly preferably 15% by mass or more when the reactive group-containing monomer is a hydroxyl group-containing monomer. In addition, the (meth)acrylic acid ester polymer (A) preferably contains a reactive group-containing monomer as the upper limit of 35% by mass or less, particularly 30% by mass or less, as a monomer unit constituting the polymer. It is preferably contained, more preferably 25% by mass or less, and when the reactive group-containing monomer is a carboxy group-containing monomer, it is preferably contained 20% by mass or less, and 12% by mass or less. is particularly preferred. 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 coloring agent (D) in the adhesive tends to be good, and the obtained adhesive has a total light transmittance and lightness L* (and chromaticity a* and b*, and haze value) The reproducibility and uniformity of the image are improved, and excellent appearance harmony and character visibility are exhibited. Furthermore, when the reactive group-containing monomer is a hydroxyl group-containing monomer, if the content is 15% by mass or more, a predetermined amount of hydroxyl groups will remain in the adhesive. Hydroxyl groups are hydrophilic groups, and if such hydrophilic groups are present in a predetermined amount in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, they will penetrate into the adhesive under such high temperature and high humidity conditions. As a result, whitening of the pressure-sensitive adhesive when returned to normal temperature and normal humidity is suppressed (excellent resistance to moist heat whitening).

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

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

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

The (meth)acrylic acid ester polymer (A) preferably contains 40% by mass or more, particularly 50% by mass or more, of (meth)acrylic acid alkyl ester as monomer units constituting the polymer. It is preferably contained in an amount of 60% 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 (meth)acrylic acid ester polymer (A) preferably contains 99% by mass or less, particularly 95% by mass or less, of (meth)acrylic acid alkyl ester as monomer units constituting the polymer. is preferred, and it is more preferred to contain 90% 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 step followability and blister resistance, as well as 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 . The reactive functional group-containing monomers described above are excluded from the nitrogen atom-containing monomers referred to herein.

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. Being a straight-chain polymer facilitates the entanglement of molecular chains, which can be expected to improve cohesive strength. Therefore, it is possible to obtain a pressure-sensitive adhesive with excellent step conformability and blister resistance under high-temperature and high-humidity conditions. easy.

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

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

The weight-average molecular weight of the (meth)acrylate polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, further preferably 400,000 or more as a lower limit. When the lower limit of the weight-average molecular weight of the (meth)acrylic acid ester polymer (A) is above, the pressure-sensitive adhesive to be obtained has more excellent step followability and blister resistance under high-temperature and high-humidity conditions. .

The upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer (A) is preferably 2,000,000 or less, more preferably 1,500,000 or less, and particularly preferably 900,000 or less. , and more preferably 600,000 or less. When the upper limit of the weight-average molecular weight of the (meth)acrylic acid ester polymer (A) is above, the pressure-sensitive adhesive to be obtained has more excellent conformability to irregularities. 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 addition, in the adhesive composition P, the (meth)acrylic acid ester polymer (A) may be used alone or in combination of two or more.

(1-2) Crosslinking agent (B)
The cross-linking agent (B) cross-links the (meth)acrylic acid ester polymer (A) by heating the pressure-sensitive adhesive composition P, making it possible to satisfactorily form a three-dimensional network structure. As a result, the cohesive force of the 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, and is preferably 0.03 parts by mass with respect to 100 parts by mass of the (meth)acrylic acid ester polymer (A). It is more preferably at least 0.05 parts by mass, and more preferably at least 0.1 parts by mass. The content is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.4 parts by mass or less. is preferred, and 0.25 parts by mass or less is most preferred. When the content of the cross-linking agent (B) is within the above range, the pressure-sensitive adhesive to be obtained exhibits good cohesive strength and is superior in conformability to unevenness under high-temperature and high-humidity conditions.

(1-3) Active energy ray-curable component (C)
In the cured adhesive obtained by curing the adhesive obtained by crosslinking the adhesive composition P according to the present embodiment with active energy rays (the adhesive constituting the cured adhesive layer), the active energy ray-curable It is presumed that the components (C) are polymerized with each other, and the polymerized active energy ray-curable component (C) is entangled 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 step followability and blister resistance under high-temperature and high-humidity conditions.

The active energy ray-curable component (C) is not particularly limited as long as it is a component that can be cured by irradiation with an active energy ray and the above effects can be obtained. 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 (C) in the adhesive composition P is the (meth)acrylic acid ester polymer ( A) With respect to 100 parts by mass, the lower limit is preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, and further preferably 4 parts by mass or more. On the other hand, the above content is preferably 20 parts by mass or less as an upper limit from the viewpoint of the adhesive strength of the cured adhesive obtained, as well as the step conformability and blister resistance under high temperature and high humidity conditions. It is particularly preferably not more than 8 parts by mass, and more preferably not more than 8 parts by mass.

(1-4) Colorant (D)
Colorant (D) is the colorant described above. The specific types and content in the adhesive are as described above.

The content of the colorant (D) 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 0.15 parts by mass or more. The content is preferably 2 parts by mass or less, more preferably 1 part by mass or less, particularly preferably 0.5 parts by mass or less, and further preferably 0.2 parts by mass or less. Preferably.

(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 (C) 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 (C). In particular, it is preferably 1 part by mass or more, more preferably 5 parts by mass or more. Also, the upper limit is preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and further preferably 12 parts by mass or less.

The mass ratio of the amount of the photopolymerization initiator (E) to the amount of the colorant (D) (photopolymerization initiator (E)/colorant (D)) is preferably 0.5 or more, particularly 1 or more. is preferable, and more preferably 2 or more. The above ratio is preferably 20 or less, more preferably 12 or less, particularly preferably 8 or less, further preferably 4 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 total light transmittance and the brightness L * are made suitable, while the active energy ray curing is more suitable. It becomes easy to obtain a pressure-sensitive adhesive having cohesive strength and adhesiveness, and it tends to be more excellent in blister resistance.

(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 and blister resistance under high temperature and high humidity conditions are more excellent. It becomes a thing.

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

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

The content of the silane coupling agent in the adhesive composition P is preferably 0.01 parts by mass or more, particularly 0.05 parts by mass, relative to 100 parts by mass of the (meth)acrylic acid ester polymer (A). It is preferably at least 0.08 part by mass, more preferably at least 0.08 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), the active energy ray-curable component (C), and the colorant (D), and optionally adding additives.

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. 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.

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

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

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

(3) Formation of Adhesive Layer The 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 obtained in this way has excellent step followability under high-temperature and high-humidity conditions.

(4) Physical properties of the adhesive The gel fraction of the adhesive according to the present embodiment is preferably 20% or more as a lower limit, more preferably 30% or more, and particularly 40% or more. Preferably, it is 45% 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 90% or less, more preferably 80% or less, particularly preferably 70% or less, and further preferably 60%. % 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 both the initial conformability to irregularities and the conformability to irregularities after durability are excellent. In addition, good adhesive strength is exhibited, and the adhesiveness to the adherend becomes more excellent. Here, the method for measuring the gel fraction of the pressure-sensitive adhesive is as shown in the test examples described later.

(5) Thickness of Adhesive Layer The thickness (Z μm) of the adhesive layer 11 in the adhesive sheet 1 according to the present embodiment is preferably a value that satisfies the aforementioned X×Z formula (I).

Specifically, the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 25 μm or more, and more preferably 40 μm or more. When the lower limit of the thickness of the pressure-sensitive adhesive layer 11 is the above, the above-mentioned total light transmittance and lightness L* (and further chromaticities a* and b*, and haze value) are easily satisfied, and desired adhesive strength is easily exhibited. In addition, from the viewpoint of easily exhibiting excellent step conformability and blister resistance, the lower limit is preferably 50 μm or more, more preferably 75 μm or more, and particularly preferably 100 μm or more. It is more preferably 120 μm or more.

The upper limit of the thickness of the pressure-sensitive adhesive layer 11 is preferably 1000 μm or less, more preferably 500 μm or less, particularly preferably 300 μm or less, further preferably 250 μm or less. When the upper limit value of the thickness of the pressure-sensitive adhesive layer 11 is above, workability becomes favorable. In addition, it is less likely that defects in appearance due to push marks or the like will occur. Furthermore, in relation to the content of the colorant (D), the aforementioned total light transmittance and lightness L* (and chromaticity a* and b* and haze value) are easily satisfied. In addition, the 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 adhesive layer 11 until the adhesive sheet 1 is used, and are peeled off when the adhesive sheet 1 (adhesive layer 11) is used. In the adhesive sheet 1 according to this embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

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

The release surfaces of the release sheets 12a and 12b (especially the surfaces in contact with the pressure-sensitive adhesive layer 11) are preferably subjected to a release treatment. Examples of release agents used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. Of the release sheets 12a and 12b, 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. Manufacture of Adhesive Sheet As an example of manufacturing the adhesive sheet 1, the coating solution of the adhesive composition P is applied to the release surface of one of the release sheets 12a (or 12b) and heat-treated to form the adhesive composition. After thermally cross-linking P 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 adhesive layer 11 as it is. As a result, the pressure-sensitive adhesive sheet 1 is obtained. The conditions for heat treatment and curing are as described above.

As another production example of the adhesive sheet 1, the coating solution of the adhesive composition P is applied to the release surface of one release sheet 12a, heat treatment is performed to thermally crosslink the adhesive composition P, and the coating is performed. A 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 adhesive layer 11 as it is. As a result, the pressure-sensitive adhesive sheet 1 is obtained. According to this production example, even when the 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 post-curing pressure-sensitive adhesive layer 11 ′ located between them 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 on the side bonded by the adhesive layer 11' after curing. In the present embodiment shown in FIG. 2, the first display member constituting member 21 has a step such as the printed layer 3 on the surface on the post-curing pressure-sensitive adhesive layer 11' side.

The post-curing adhesive layer 11 ′ in the display member 2 is obtained by curing the adhesive layer 11 of the adhesive sheet 1 described above by irradiating active energy rays. When the adhesive composition P is used to form the adhesive layer 11, the cured adhesive constituting the cured adhesive layer 11′ is composed of the (meth)acrylic acid ester polymer (A) and the cross-linking agent (D ), contains a cured product (polymer) of the active energy ray-curable component (C), and optionally further contains a photopolymerization initiator (E) and additives. It is presumed that the active energy ray-curable component (C) polymerizes to form a three-dimensional network structure in which the network is somewhat coarse, and is entangled with the crosslinked structure to form a higher-order structure. . Such a structure exhibits excellent blister resistance.

The photopolymerization initiator (E) contained in the post-curing adhesive constituting the post-curing pressure-sensitive adhesive layer 11′ is the photopolymerization initiator (E) contained in the adhesive composition P, which is active energy It remained without being cleaved even by radiation irradiation. Therefore, its content is not large, and is usually 0.00001% by mass or more and 0.1% by mass or less, preferably 0.0001% by mass or more and 0.01% by mass or less in the adhesive. .

The thickness of the cured adhesive layer 11 ′ is basically the same as the thickness of the adhesive layer 11 of the adhesive sheet 1 .

The lower limit of the gel fraction of the cured adhesive constituting the cured adhesive layer 11′ is preferably 55% or more, more preferably 60% or more, and particularly preferably 65% or more. Preferably, it is 67% or more. When the lower limit of the gel fraction of the post-curing adhesive is above, the blister resistance of the post-curing adhesive layer 11' becomes more excellent. In addition, the upper limit of the gel fraction of the adhesive after curing is preferably 95% or less, more preferably 90% or less, particularly preferably 80% or less, and further preferably 74% or less. Preferably. When the upper limit of the gel fraction of the cured adhesive is above, the adhesive strength of the cured adhesive layer 11′, as well as step followability and blister resistance under high temperature and high humidity conditions, become more excellent. . The method for measuring the gel fraction of the adhesive after curing is as shown in the test examples described later.

The adhesive strength of the cured adhesive layer 11' to soda lime glass is preferably 10 N/25 mm or more, preferably 20 N/25 mm or more, and more preferably 30 N/25 mm or more as a lower limit. It is particularly preferably 40 N/25 mm or more, more preferably 50 N/25 mm or more. When the lower limit of the adhesive strength is above, the step followability and blister resistance under high-temperature and high-humidity conditions are more excellent. Although the upper limit of the adhesive strength is not particularly limited, it is preferably 100 N/25 mm or less, more preferably 80 N/25 mm or less, and particularly preferably 60 N/25 mm or less.

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

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 a laminate containing them, particularly a plastic plate or a laminate containing a plastic plate. It is preferably a protective panel. In this case, the printed layer 3 is generally formed in a frame shape on the post-curing adhesive layer 11 ′ side of the first display member constituting member 21 .

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

Generally, when a plastic plate is placed under high-temperature conditions, for example, 85° C., the internal low-boiling-point component evaporates, and air bubbles and floats appear at the interface between the plastic plate and the adhesive layer 11′ after curing. , there is a risk that blisters such as peeling will occur. However, even if the display body 2 according to the present embodiment includes such a plastic plate, when the adhesive composition P is used to form the adhesive layer 11, the adhesive layer 11′ after curing causes blistering. can be suppressed satisfactorily.

The plastic plate is not particularly limited, and examples thereof include acrylic resin plates such as a polycarbonate resin (PC) plate and a polymethyl methacrylate resin (PMMA) plate, acrylic resin such as a polymethyl methacrylate resin layer on a polycarbonate resin plate. Examples include a plastic plate having laminated layers. The above-mentioned polycarbonate resin plate may contain a resin other than polycarbonate resin as a constituent material, and the above-mentioned acrylic resin plate may contain a resin other than acrylic resin as a constituent material. may contain. The plastic plate may contain an ultraviolet absorber.

The thickness of the plastic plate is not particularly limited, but is usually 0.2 to 5 mm, preferably 0.4 to 3 mm, particularly preferably 0.6 to 2.5 mm, and more preferably 1 to 5 mm. 2.1 mm.

Various functional layers (transparent conductive film, metal layer, silica layer, hard coat layer, antiglare layer, etc.) may be provided on one or both sides of the glass plate or plastic plate, or an optical member may be laminated. may have been 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 post-curing pressure-sensitive adhesive layer 11 ′ from deteriorating in conformability to unevenness with respect to the printed layer 3 .

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

Next, the other release sheet 12b is peeled off from the adhesive layer 11 of the adhesive sheet 1, and the exposed adhesive layer 11 of the adhesive sheet 1 and the second display member constituting member 22 are laminated to obtain a laminate. . 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.

After that, the adhesive layer 11 in the laminate is irradiated with an active energy ray. As a result, the energy ray-curable component (C) in the pressure-sensitive adhesive layer 11 is polymerized, and the pressure-sensitive adhesive layer 11 is cured to form a cured pressure-sensitive adhesive layer 11'. Irradiation of energy rays to the pressure-sensitive adhesive layer 11 is usually carried out through either the first display member constituting member 21 or the second display member constituting member 22, preferably through the first display member as a protective panel. It is carried out over the constituent member 21 .

Here, 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.

As shown in FIG. 3, the display body 2 according to the present embodiment preferably has a frame member 4 on the periphery of the display body 2. As shown in FIG. 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 post-curing pressure-sensitive adhesive layer 11' in the present embodiment has an increased sense of unity with the frame material 4, and has better harmony.

In the display body 2, a sense of unity with the black frame material 4 is given by the post-curing adhesive layer 11' that inherits the physical properties (total light transmittance, brightness L*, etc.) of the adhesive layer 11 described above. , has excellent appearance harmony. Further, the display body 2 ensures visibility as a display body.

Furthermore, in the display body 2, when the adhesive layer 11 is formed from the adhesive composition P, the post-curing adhesive layer 11' has excellent step followability 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 air bubbles, floating, peeling, etc. near the steps is suppressed.

Further, in the display body 2, when the pressure-sensitive adhesive layer 11 is formed from the pressure-sensitive adhesive composition P, the cured pressure-sensitive adhesive layer 11' has excellent blister resistance. Even when placed under wet conditions (for example, 85° C., 85% RH) and outgassing is generated from the first display body constituent member 21 and/or the second display body constituent member 22, the cured pressure-sensitive adhesive layer 11 ' and the display body constituent members 21 and 22, the occurrence of blisters such as air bubbles, floating, and peeling is suppressed.

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

For example, one or both of the release sheets 12a and 12b in the adhesive sheet 1 may be omitted, or a desired optical member may be laminated instead of the release sheets 12a and/or 12b. Further, the first display member constituting member 21 may not have steps. Furthermore, not only the first display body constituent member 21 but also the second display body constituent member 22 may have a step on the post-curing 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 65 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of isobornyl acrylate, 10 parts by weight of N-acryloylmorpholine, and 15 parts by weight of 2-hydroxyethyl acrylate were copolymerized by a solution polymerization method. Polymerization was performed to prepare a (meth)acrylate polymer (A). When the molecular weight of this (meth)acrylate polymer (A) was measured by the method described later, it was found to have a weight average molecular weight (Mw) of 500,000.

2. Preparation of adhesive composition 100 parts by mass of the (meth)acrylic acid ester polymer (A) obtained in the above step 1 (solid content conversion value; the same applies hereinafter), and a trimethylolpropane-modified trimethylolpropane-modified trimethylolpropane 0.2 parts by mass of diisocyanate (manufactured by Toyochem, product name “BHS8515”) and ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate (C1: New Nakamura Kagaku Co., Ltd., product name "NK Ester A-9300-1CL") 5.0 parts by mass, and a carbon black-based black pigment (Toyocolor Co., Ltd., "Multilac Black") as a coloring agent (D) 0.5 parts by mass. 08 parts by mass, 0.5 parts by mass of a mixture (E1) of 1:1 mass ratio of 1-hydroxycyclohexylphenyl ketone and benzophenone as a photopolymerization initiator (E), and 3-glycine as a silane coupling agent. 0.1 part by mass of sidoxypropyltrimethoxysilane 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). Also, the mass ratio of the amount of photopolymerization initiator (E) to the amount of colorant (D) (photopolymerization initiator (E)/colorant (D)) was calculated and shown in Table 1. Details of abbreviations and the like in Table 1 are as follows.
[(Meth) acrylic ester polymer (A)]
2EHA: 2-ethylhexyl acrylate IBXA: isobornyl acrylate ACMO: N-acryloylmorpholine HEA: 2-hydroxyethyl acrylate MMA: methyl methacrylate BA: n-butyl acrylate AA: acrylic acid
[Crosslinking agent (B)]
TDI: trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem, product name “BHS8515”)
XDI: trimethylolpropane-modified xylylene diisocyanate (manufactured by Soken Chemical Co., Ltd., product name “TD-75”)
Epoxy: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, product name “TETRAD-C”)
[Active energy ray-curable component (C)]
C1: ε-caprolactone-modified tris-(2-acryloxyethyl) isocyanurate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name “NK Ester A-9300-1CL”)
C2: tricyclodecanedimethanol diacrylate
[Colorant (D)]
Pigment: Carbon black-based black pigment (manufactured by Toyocolor Co., Ltd., "Multi-Lack Black")
Dye: Nigrosine-based black dye (manufactured by Orient Chemical Industry, product name “NUBIAN BLACK PA-2802”)
[Photoinitiator (E)]
E1: Mixture of 1-hydroxycyclohexylphenyl ketone and benzophenone at a mass ratio of 1:1 E2: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide

3. Manufacture of adhesive sheets

The coating solution of the adhesive composition obtained in the above step 2 is peeled off from a heavy-release type release sheet (manufactured by Lintec, product name "SP-PET752150") in which one side of a polyethylene terephthalate film is release-treated with a silicone-based release agent. It was applied to the treated surface with a knife coater. Then, the coating layer was heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 25 μm), thereby producing a heavy release release sheet with a coating layer.

On the other hand, the coating solution of the adhesive composition obtained in the above step 2 is applied to a light release type release sheet (manufactured by Lintec, product name "SP-PET382120") obtained by releasing one side of a polyethylene terephthalate film with a silicone release agent. was applied to the release-treated surface of the sheet with a knife coater. Then, the coating layer was heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 25 μm), thereby producing four light release type release sheets with a coating layer.

The coating layer side surface of the heavy release release sheet with the coating layer obtained above and the coating layer side surface of one of the light release release sheets with the coating layer obtained above were pasted. Together, a first laminate was obtained in which a coating layer having a thickness of 50 μm was sandwiched between the heavy release type release sheet and the light release type release sheet.

Next, the light release release sheet is peeled off from the first laminate, and the exposed surface of the exposed coating layer and the coating layer on one of the light release release sheets with the coating layer obtained above are A second laminate was obtained in which a coating layer having a thickness of 75 μm was sandwiched between the heavy release type release sheet and the light release type release sheet. By repeating the same steps, a fourth laminate was obtained in which a coating layer having a thickness of 125 μm was sandwiched between a heavy release type release sheet and a light release type release sheet.

After that, the fourth laminate was cured under conditions of 23° C. and 50% RH for 7 days to obtain a structure of heavy release release sheet/adhesive layer (thickness: 125 μm)/light release release sheet. A pressure-sensitive adhesive sheet was produced.

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

[Examples 2 to 11, Comparative Examples 1 to 2, Reference Example 1]
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 cross-linking agent (B) , the type and amount of the active energy ray-curable component (C), the type and amount of the colorant (D), the type and amount of the photopolymerization initiator (E), and the amount of the silane coupling agent. A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except for changing as shown in 1.

Here, when the content of the colorant in the pressure-sensitive adhesive layer (adhesive composition) formed in Examples, Comparative Examples, and Reference Examples is X% by mass, and the thickness of the pressure-sensitive adhesive layer is Z μm, X× Z was calculated. Table 1 shows the results.

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 gel fraction)
The pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples were cut into a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed with a precision balance. , the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M1.

Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23° C.) for 24 hours. After that, the pressure-sensitive adhesive was taken out and air-dried for 24 hours in an environment of a temperature of 23° C. and a relative humidity of 50%, and further dried in an oven of 80° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. Let the mass at this time be M2. A gel fraction (%) is represented by (M2/M1)×100. From this, the gel fraction (before UV irradiation) of the adhesive was derived. Table 2 shows the results.

On the other hand, the adhesive layers of the adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples were irradiated with active energy rays (ultraviolet rays; UV) under the following conditions through a light release type release sheet, and the adhesive was The layer was cured to form a cured adhesive layer. For the adhesive sheet of Example 7, a plastic plate (manufactured by Mitsubishi Gas Chemical Company, Inc., product name " Iupilon Sheet MR58U", thickness: 0.7 mm, containing an ultraviolet absorber) was superimposed, and an active energy ray was irradiated through the plastic plate. Regarding the adhesive of the adhesive layer after curing, the gel fraction (after UV irradiation) was derived in the same manner as described above. Table 2 shows the results.

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

[Test Example 2] (Measurement of total light transmittance)
The pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference 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 "NDH-5000"). Transmittance (%) was measured. Table 2 shows the results.

[Test Example 3] (Measurement of haze value)
The haze of the adhesive layers of the adhesive sheets obtained in Examples, Comparative Examples and Reference Examples was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH-5000") in accordance with JIS K7136:2000. Value (%) was measured. Table 2 shows the results.

[Test Example 4] (Measurement of L*a*b*)
The pressure-sensitive adhesive layers of the pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples and Reference Examples were analyzed using a simultaneous photometric spectrophotometer (manufactured by Nippon Denshoku Industries Co., Ltd., product name "SQ2000"), and CIE1976L*a*b *Lightness L*, chromaticity a* and chromaticity b* defined by the color system were measured. Table 2 shows the results.

[Test Example 5] (Measurement of adhesive strength)
The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples, and the exposed pressure-sensitive adhesive layer was coated 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 heavy release type release sheet/adhesive layer/PET film. The laminate thus obtained was cut into a piece having a width of 25 mm and a length of 100 mm, which was used as a sample.

In an environment of 23 ° C. and 50% RH, the heavy release type release sheet was peeled off from the sample, and the exposed adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.). pressure was applied at 0.5 MPa and 50° C. for 20 minutes. After that, it was left under the conditions of 23° C. and 50% RH for 24 hours.

Next, an active energy ray was irradiated through the heavy release type release sheet under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. For the pressure-sensitive adhesive sheet of Example 7, a plastic plate obtained by laminating a PMMA layer on a PC plate (Mitsubishi Gas Chemical Co., Ltd., product name "Iupilon Sheet MR58U", thickness: 0.5 mm) was placed on a heavy-release type release sheet. 7 mm, containing an ultraviolet absorber) were superimposed, and an active energy ray was irradiated through the plastic plate. In Reference Example 1, the active energy ray was not irradiated. Then, using a tensile tester (manufactured by Orientec, product name "Tensilon"), the adhesive strength (N/25 mm) was measured under the conditions of a peel speed of 300 mm/min and a peel angle of 180 degrees. Conditions other than those described here were measured according to JIS Z0237:2009. Table 2 shows the results.

[Test Example 6] (Evaluation of appearance harmony)
The pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples were cut into 70 mm length × 70 mm width, and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was applied to two soda-lime glass plates (manufactured by Nippon Sheet Glass Co., Ltd., length 70 mm × width). 70 mm×1.1 mm in thickness). Next, through one of the soda-lime glass plates, an active energy ray was irradiated under the same conditions as in Test Example 1 to cure the adhesive layer to form a cured adhesive layer, which was used as a sample. In Reference Example 1, the active energy ray was not irradiated.

The resulting sample was placed on black printed paper (L*: 29.8, a*: -0.7, b*: 0.6) as a background. Then, whether the sample is familiar with the background (there is a sense of unity with the background) is visually judged under a three-wavelength fluorescent lamp (distance from the fluorescent lamp: 200 cm). Concordance was evaluated. Table 2 shows the results.
⊚: The sample blended well with the background.
◯: The sample blended well with the background to some extent.
x: The sample clearly did not blend in with the background.

The color of the paper printed in black (L*a*b* defined by the CIE 1976 L*a*b* color system) is determined by a spectrophotometer (manufactured by BYK, product name “Spectro-Guide” ).

[Test Example 7] (Evaluation of character visibility)
On a display with a size of 15.6 inches and a resolution of 1366 x 768 (manufactured by Fujitsu Ltd., product name “LITEBOOK A574/H”), white background, black characters (font: MS P Gothic) are displayed in a size of 5 to 20 points. 100% is displayed in increments of 1 point.

A sample prepared in the same manner as in Test Example 6 was placed on the display. Then, at a position of 50 cm from the display, the size of characters that can be visually recognized was confirmed, and character visibility was evaluated according to the following criteria. Table 2 shows the results.
(double-circle): The character of 8 points was visually recognized.
◯: 8-point characters were not completely visible, but 15-point characters were visible.
x: 15-point characters were not visible.

[Test Example 8] (Evaluation of step followability)
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 5 μm and 10 μm was produced.

The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples, and the exposed pressure-sensitive adhesive layer was coated with a polyethylene terephthalate (PET) film having an easy-adhesion layer (manufactured by Toyobo Co., Ltd., product name "PET A4300", thickness: 100 µm). Then, the heavy release type release sheet was peeled off to expose the pressure-sensitive adhesive layer. Using a laminator (manufactured by Fujipla Co., Ltd., product name "LPD3214"), the laminate was laminated to each stepped glass plate so that the pressure-sensitive adhesive layer covered the entire printed surface of the picture frame. After that, it was autoclaved for 20 minutes under the conditions of 50° C. and 0.5 MPa, and allowed to stand at normal pressure, 23° C. and 50% RH for 24 hours.

Next, an active energy ray was irradiated through the PET film under the same conditions as in Test Example 1 to cure the pressure-sensitive adhesive layer to obtain a cured pressure-sensitive adhesive layer. For the adhesive sheet of Example 7, a plastic plate (Mitsubishi Gas Chemical Co., Ltd., product name "Iupilon Sheet MR58U", thickness: 0.7 mm, PC plate laminated with PMMA layer) was placed on the PET film. containing an ultraviolet absorber) was superimposed, and an active energy ray was irradiated through the plastic plate. Subsequently, it was stored for 72 hours under wet heat conditions of 85° C. and 85% RH. After that, the step followability was evaluated based on the following criteria. The step followability is judged to be good when the printing step is completely filled with the adhesive layer after curing, and when lifting or peeling is observed at the interface between the printing step and the adhesive layer after curing , it is determined that the printing step could not be followed. In Reference Example 1, the step followability was evaluated in the same manner as described above, except that the active energy ray was not irradiated. Table 2 shows the results.
◎: Good with a printing step of 10 μm ○: Good with a printing step of 5 μm ×: Lifting and peeling with a printing step of 5 μm

[Test Example 9] (Evaluation of blister resistance)
The light-release type release sheet was peeled off from the pressure-sensitive adhesive sheets obtained in Examples, Comparative Examples, and Reference Examples, and the exposed pressure-sensitive adhesive layer was applied to a plastic plate (manufactured by Mitsubishi Gas Chemical Company, Inc., product name " Iupilon Sheet MR58U", thickness: 0.7 mm, containing ultraviolet absorber) was laminated to the PC board side to obtain a plastic board with an adhesive layer.

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

Next, the adhesive layer was irradiated with an active energy ray under the same conditions as in Test Example 1 through a soda lime glass plate to cure the adhesive layer to obtain a cured adhesive layer. In addition, only in Example 7, the active energy rays were irradiated not through the soda-lime glass plate but through the plastic plate. In this way, a structure (70 mm×150 mm) was obtained in which the plastic plate and the glass plate were bonded together by the post-curing adhesive layer.

The above structure was stored for 72 hours under high temperature and high humidity conditions of 85° C. and 85% RH. After curing, the state of the interface between the adhesive layer and the adherend (plastic plate, glass plate) was visually observed, and the blister resistance was evaluated according to the following criteria. In Reference Example 1, blister resistance was evaluated in the same manner as described above, except that the active energy ray was not applied. Table 2 shows the results.
⊚: There was no air bubble, floating or peeling.
◯: No lifting or peeling, and a few air bubbles were generated, but the level was not a problem.
Δ: There was no lifting or peeling, but many air bubbles were generated.
x: Lifting and peeling occurred.

As can be seen from Table 2, the products using the pressure-sensitive adhesive sheets obtained in Examples were excellent in appearance harmony and character visibility, as well as step conformability and blister resistance.

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

DESCRIPTION OF SYMBOLS 1... Adhesive sheet 11... Adhesive layer 12a, 12b... Release sheet 2... Display body 11'... Adhesive layer after hardening 21... First display body constituent member 22... Second display body constituent member 3... Printing layer 4 …frame material

Claims (16)

A pressure-sensitive adhesive sheet having a colored pressure-sensitive adhesive layer for bonding one display body constituent member and another display body constituent member,
The colored adhesive layer is made of an active energy ray-curable colored adhesive,
The colored adhesive contains a coloring agent,
The gel fraction of the colored adhesive is 55% or less,
The colored pressure-sensitive adhesive layer has a haze value of 80% or less,
A pressure-sensitive adhesive sheet, wherein the lightness L* of the colored pressure-sensitive adhesive layer defined by the CIE1976 L*a*b* color system is 95 or less. A pressure-sensitive adhesive sheet having a colored pressure-sensitive adhesive layer for bonding one display body constituent member and another display body constituent member,
The colored adhesive layer is made of an active energy ray-curable colored adhesive,
The colored adhesive contains a coloring agent,
The colored adhesive does not contain an active energy ray-curable monofunctional monomer,
The colored pressure-sensitive adhesive layer has a haze value of 80% or less,
The lightness L* of the colored pressure-sensitive adhesive layer defined by the CIE1976 L*a*b* color system is 95 or less.
An adhesive sheet characterized by: 3. The pressure-sensitive adhesive sheet according to claim 1 , wherein the colored pressure-sensitive adhesive contains a photopolymerization initiator. The colored adhesive contains a photopolymerization initiator,
The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the mass ratio of the amount of the photopolymerization initiator to the amount of the colorant is 0.5 or more and 20 or less. 5. The pressure-sensitive adhesive sheet according to claim 3 , wherein the photopolymerization initiator is of the phosphine oxide type. A pressure-sensitive adhesive sheet having a colored pressure-sensitive adhesive layer for bonding one display body constituent member and another display body constituent member,
The colored adhesive layer is made of an active energy ray-curable colored adhesive,
The colored adhesive contains a coloring agent,
The colored adhesive contains a phosphine oxide-based photopolymerization initiator,
The colored pressure-sensitive adhesive layer has a haze value of 80% or less,
The lightness L* of the colored pressure-sensitive adhesive layer defined by the CIE1976 L*a*b* color system is 95 or less.
An adhesive sheet characterized by: The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the coloring agent is a black pigment or dye. The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the content of the coloring agent in the colored pressure-sensitive adhesive is 0.01% by mass or more and 2.0% by mass or less. The adhesive strength of the colored pressure-sensitive adhesive layer to soda lime glass after bonding the colored pressure-sensitive adhesive layer to soda lime glass and irradiating the active energy ray is 10 N/25 mm or more and 100 N/25 mm or less. The pressure-sensitive adhesive sheet according to any one of claims 1 to 8 . two release sheets;
The pressure-sensitive adhesive sheet according to any one of claims 1 to 9 , further comprising the colored pressure-sensitive adhesive layer sandwiched between the two release sheets so as to be in contact with the release surfaces of the two release sheets. one display body constituent member;
other display body constituent members;
A display body comprising a post-curing colored adhesive layer for bonding the one display body constituent member and the other display body constituent member to each other,
The post-curing colored pressure-sensitive adhesive layer is a post-curing colored pressure-sensitive adhesive layer obtained by curing the colored pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to any one of claims 1 to 10 with an active energy ray. display body. 12. The method according to claim 11 , wherein at least one of the one display body constituting member and the other display body constituting member has a step on a side to be bonded by at least the post-curing colored pressure-sensitive adhesive layer. display body. 13. The display according to claim 11 , wherein at least one of the one display body constituent member and the other display body constituent member contains an ultraviolet absorber. 14. The display according to any one of claims 11 to 13 , characterized by having a black frame material. A laminated body is produced by laminating one display body constituent member and another display body constituent member via the colored adhesive layer of the adhesive sheet according to any one of claims 1 to 10 ,
A method for producing a display, comprising irradiating the colored pressure-sensitive adhesive layer of the laminate with an active energy ray to cure the colored pressure-sensitive adhesive layer to form a cured colored pressure-sensitive adhesive layer. A laminate is produced by laminating one display body component and another display body component with the colored adhesive layer of the pressure-sensitive adhesive sheet according to claim 5 or 6 interposed therebetween,
The colored adhesive layer of the laminate is irradiated with ultraviolet rays through one display body component containing an ultraviolet absorber, and the colored adhesive layer is cured to form a cured colored adhesive layer. A manufacturing method of a display body characterized by:

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