TWI769991B - Adhesive composition, adhesive, adhesive sheet and display - Google Patents

Abstract

Provided are an adhesive composition, an adhesive, an adhesive sheet, and a display that maintain performance as an adhesive for displays and are excellent in reworkability.

An adhesive composition for forming an adhesive layer for laminating a display body component and another display body component, comprising a (meth)acrylate copolymer (A), a crosslinking agent (B) and The compound (C), the (meth)acrylate copolymer (A) contains a reactive group-containing monomer having a reactive group in the molecule that reacts with the crosslinking agent (B) as the monomer unit constituting the polymer, Furthermore, the weight average molecular weight is 400,000 or more and 1.3 million or less, the compound (C) has an alkylene oxide moiety, and does not have or has one reactive group that reacts with the crosslinking agent (B).

Description

Adhesive composition, adhesive, adhesive sheet and display

The present invention relates to an adhesive composition, an adhesive, and an adhesive sheet for laminating components of a display body, and a display body obtained by using the adhesive layer of the adhesive sheet.

In recent years, various mobile electronic devices such as mobile phones, smart phones, and tablet computers include displays using display modules including liquid crystal elements, light emitting diodes (LED elements), and organic electroluminescence (organic EL) elements. (display: display).

In this type of display, a protection panel is usually provided on the surface side of the display module. A gap is provided between the protection panel and the display module, so as to prevent the deformed protection panel from colliding with the display module when the protection panel is deformed by an external force.

However, if there is an air layer as described above, the reflection loss of light caused by the difference in refractive index between the protective panel and the air layer and the difference in refractive index between the air layer and the display module increases, and there is a display The problem of image quality degradation.

Therefore, it is proposed to improve the image quality of the display by filling the gap between the protective panel and the display module with an adhesive layer. However, on the display module side of the protective panel, the frame-shaped printed layer may exist as a level difference. If the adhesive layer does not follow the step, the adhesive layer floats near the step, thereby producing Reflection loss of generated light. Therefore, step followability is required for the above-mentioned adhesive layer.

In order to solve the above-mentioned problems, Patent Document 1 discloses that the shear storage elastic modulus (G') at 25° C. and 1 Hz is 1.0× as an adhesive layer for filling the gap between the protective panel and the display module. An adhesive layer with a gel fraction of 10 ⁵ Pa or less and a gel fraction of 40% or more.

【Prior technical literature】

【Patent Literature】

[Patent Document 1] Japanese Patent Application Laid-Open No. 2010-97070

In Patent Document 1, it is intended to improve step followability by lowering the storage elastic modulus at room temperature in the adhesive layer. However, if the storage elastic modulus at normal temperature is lowered as described above, the storage elastic modulus at high temperature is lowered too much, and a problem occurs under durable conditions. For example, when high-temperature and high-humidity conditions are applied, problems such as generation of air bubbles and the like occur in the vicinity of the level difference.

In addition, the bonding of the protective panel and the display module is often performed using the adhesive sheet having the above-mentioned adhesive layer. When performing this bonding, the bonding position may deviate. In particular, it is more difficult to bond hard materials (hard bodies) such as protective panels and display modules with an adhesive sheet than to bond films to each other or a film to a hard body, and the yield during bonding tends to decrease.

Here, the price of the display module is high. Therefore, when the above-mentioned problem of lamination deviation occurs, if at least the display module side can be reused, the production cost can be reduced. Therefore, the above-mentioned adhesive sheet is expected to be able to The reworkability of peeling off the two rigid bodies bonded by the adhesive sheet enables at least the reuse of the display module.

The present invention has been made in view of such a situation, and an object thereof is to provide an adhesive composition, an adhesive, an adhesive sheet, and a display which maintain performance as an adhesive for displays and are excellent in reworkability.

In order to achieve the above objects, firstly, the present invention provides an adhesive composition for forming an adhesive layer for laminating one display body component and another display body component, which is characterized by containing: (meth)acrylic acid Ester copolymer (A); crosslinking agent (B); and compound (C), wherein the (meth)acrylate copolymer (A) contains a reactive group in the molecule that reacts with the crosslinking agent (B) The reactive group-containing monomer is used as the monomer unit constituting the polymer, and the weight average molecular weight is 400,000 or more and 1.3 million or less, and the aforementioned compound (C) has an alkylene oxide moiety, and does not have or has one cross-linked with the aforementioned The reactive group for the reaction of the linking agent (B) (Invention 1).

The adhesive obtained by cross-linking the adhesive composition of the above invention (Invention 1) exhibits good flexibility through the (meth)acrylate copolymer (A) having a relatively low weight average molecular weight, and becomes a Those with excellent step followability. In addition, by containing the compound (C), the adhesive maintains the performance as an adhesive for displays and is excellent in reworkability.

In the above invention (Invention 1), the aforementioned compound (C) has a linear structure and has an alkyl group at both ends or one end thereof (Invention 2), or the aforementioned compound (C) has a linear structure and has an alkyl group at both ends thereof. It is preferable to have a (meth)acryloyl group at one terminal or one terminal (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable to contain the compound (C) in an amount of 0.2 parts by mass or more and less than 10 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A) (Invention 4). ).

In the above inventions (Inventions 1 to 4), it is preferable that the (meth)acrylate copolymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer (Invention 5).

In the above inventions (Inventions 1 to 5), it is preferable that the one display body constituting member and the other display body constituting member are rigid bodies (Invention 6).

In the above-mentioned inventions (Inventions 1 to 6), it is preferable that the surface of the one display body constituent member has a level difference at least on the surface on the side to be bonded (Invention 7).

Second, the present invention provides an adhesive obtained by cross-linking the aforementioned adhesive compositions (Inventions 1 to 7) (Invention 8).

Third, the present invention provides an adhesive sheet, which has an adhesive layer for laminating one display component member and another display component component, characterized in that: the above-mentioned adhesive layer contains an adhesive (Invention 8) (Invention 8) 9).

In the above invention (Invention 9), the thickness of the adhesive layer is preferably 20 μm or more and 500 μm or less (Invention 10).

In the above inventions (Inventions 9 and 10), the adhesive sheet includes two peeling sheets, and the adhesive layer is preferably sandwiched by the peeling sheets so as to be in contact with the peeling surfaces of the two peeling sheets (Invention 11) .

Fourth, the present invention provides a display body constituting member; another display body constituting member; It is the adhesive layer (Invention 12) of the adhesive sheet (Inventions 9 to 11).

Furthermore, the present invention provides an adhesive sheet having an adhesive layer for laminating one display component and another display component, wherein the adhesive layer comprises a (meth)acrylate copolymer containing An adhesive formed by cross-linking the adhesive composition of the compound (A), the cross-linking agent (B) and the compound (C), the (meth)acrylate copolymer (A) contains the cross-linking agent in the molecule (B) The reactive group-containing monomer that reacts with the reactive group is used as the monomer unit constituting the polymer, and the compound (C) has an alkylene oxide moiety and does not have or has one cross-linked with the above-mentioned compound (C). In the compound of the reactive group with which the linking agent (B) reacts, the thickness of the adhesive layer is 20 μm or more and 500 μm or less.

The adhesive composition, adhesive, adhesive sheet and display of the present invention can maintain the performance as an adhesive for a display and are excellent in reworkability.

1‧‧‧Adhesive Sheet

11‧‧‧Adhesive layer

12a, 12b‧‧‧Peeling sheet

2‧‧‧Display

21‧‧‧First Display Body Components

22‧‧‧Second display body components

3‧‧‧Printing layer

Fig. 1 is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of a laminate according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.

[Adhesive composition]

The adhesive composition of the present embodiment (hereinafter sometimes referred to as "adhesive composition P".) is an adhesive composition for forming an adhesive layer for laminating one display component member and another display component member . The display body and the display body constituent members will be described later.

The adhesive composition P preferably contains a (meth)acrylate copolymer (A), a crosslinking agent (B), a compound (C), and further contains a silane coupling agent (D). In addition, in this specification, (meth)acrylic acid represents both acrylic acid and methacrylic acid. The same applies to other similar terms.

The (meth)acrylate copolymer (A) contains a reactive group-containing monomer having a reactive group that reacts with the crosslinking agent (B) as a monomer unit constituting the polymer, and has a weight-average molecular weight of 400,000 Above and below 1.3 million. In addition, the compound (C) is a compound which has an alkylene oxide moiety and does not have or has one reactive group which reacts with the crosslinking agent (B).

When the weight average molecular weight of the (meth)acrylate copolymer (A) is in a relatively low range as described above, the obtained adhesive exhibits good flexibility and is excellent in step followability. In addition, the weight average molecular weight in this specification is the standard polystyrene conversion value measured by gel permeation chromatography (GPC).

Furthermore, when the adhesive composition P contains the above-mentioned compound (C), the adhesive obtained by crosslinking the adhesive composition P is excellent in reworkability while maintaining the performance as an adhesive for displays. In particular, as described above, when the weight average molecular weight of the (meth)acrylate copolymer (A) is relatively low, the obtained adhesive becomes soft and tends to have poor reworkability. Using the above-mentioned compound (C), excellent reworkability can be obtained. That is, in the adhesive obtained by crosslinking the adhesive composition P, the compound (C) functions as an excellent rework agent. Therefore, the adhesive sheet having the adhesive layer containing the adhesive can be easily peeled off from the display-constituting member even after being temporarily attached to the display-constituting member, Reuse of the display body constituent member can be realized.

It is considered that the above-mentioned excellent reworkability is mainly exerted by the alkylene oxide moiety possessed by the compound (C). Furthermore, compatibility with the (meth)acrylate copolymer (A) can be ensured by the fact that the compound (C) does not have or has a reactive group that reacts with the crosslinking agent (B). Furthermore, the reaction of the (meth)acrylate copolymer (A) and the crosslinking agent (B) is not hindered by the compound (C), a good crosslinked structure can be formed, and the obtained adhesive exhibits a desired cohesive force. Therefore, the performance as an adhesive for a display body is maintained, and the step followability and the like under high temperature and high humidity conditions can be particularly well exhibited.

(1) (Meth)acrylate copolymer (A)

The (meth)acrylate copolymer (A) contains, as a monomer unit constituting the polymer, a reactive group-containing monomer having a reactive group that reacts with the crosslinking agent (B) in the molecule. The reactive group derived from the reactive group-containing monomer reacts with the crosslinking agent (B) to form a crosslinked structure (three-dimensional network structure), and an adhesive having a desired cohesive force can be obtained.

Preferred examples of the reactive group-containing monomer include monomers having a hydroxyl group in the molecule (hydroxyl-containing monomer), monomers having a carboxyl group in the molecule (carboxyl group-containing monomer), and monomers having an amino group in the molecule. body (amine group-containing monomer), etc. Among these, the hydroxyl-containing monomer which is excellent in the reactivity with the crosslinking agent (B) and has little adverse effect on the adherend is particularly preferable. Furthermore, the carboxyl group-containing monomer is preferable from the viewpoint of exhibiting a desired cohesive force even if the weight average molecular weight of the (meth)acrylate copolymer (A) is relatively low.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. Hydroxypropyl (meth)acrylates such as hydroxypropyl, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Among them, from the viewpoint of the reactivity of the hydroxyl group in the obtained (meth)acrylate copolymer (A) with the crosslinking agent (B) and the copolymerizability with other monomers, 2-hydroxy Ethyl ester and 4-hydroxybutyl (meth)acrylate are preferred, and 2-hydroxyethyl (meth)acrylate is particularly preferred. These may be used alone or in combination of two or more.

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

As an amino group-containing monomer, aminoethyl (meth)acrylate, n-butylaminoethyl (meth)acrylate, etc. are mentioned, for example. These may be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) preferably contains a hydroxyl group-containing monomer with a lower limit of 3 mass % or more as a monomer unit constituting the polymer, more preferably 10 mass % or more, and 15 mass % % or more is further preferable. In addition, the (meth)acrylate copolymer (A) preferably contains a hydroxyl group-containing monomer having an upper limit of 35% by mass or less as a monomer unit constituting the polymer, particularly preferably 30% by mass or less, and contains 25 mass % or less is more preferable. If the (meth)acrylate copolymer (A) contains the hydroxyl group-containing monomer as a monomer unit in the above amount, a good cross-linked structure is formed in the obtained adhesive, the desired cohesion can be obtained, and the adhesive A predetermined amount of hydroxyl will remain in the base. Hydroxyl is a hydrophilic group. If the hydrophilic group exists in the adhesive in a predetermined amount, even if the adhesive is placed under high temperature and high humidity conditions, it will be different from the moisture immersed in the adhesive under the high temperature and high humidity conditions. The compatibility is also good, and as a result, the whitening of the adhesive at the time of returning to normal temperature and normal humidity can be suppressed (excellent in wet-heat whitening resistance).

When the (meth)acrylate copolymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer, the (meth)acrylate copolymer (A) contains the carboxyl group-containing monomer as follows, that is, as a The lower limit is preferably 5 mass % or more, particularly preferably 7 mass % or more, and even more preferably 10 mass % or more. In addition, the (meth)acrylate copolymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer, that is, preferably 30 mass % or less as an upper limit, and 20 mass % or less It is especially preferable, and it is more preferable to contain 15 mass % or less. When the (meth)acrylate copolymer (A) contains the carboxyl group-containing monomer as a monomer unit in the above-mentioned amount, a favorable crosslinked structure is formed in the obtained adhesive, and desired cohesion can be obtained.

Moreover, it is also preferable that the (meth)acrylate copolymer (A) does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. Since the carboxyl group is an acid component, by not containing a carboxyl group-containing monomer, even if there is a problem caused by acid in the attachment object of the adhesive, such as the presence of indium tin oxide (Tin-doped indium oxide, ITO), etc. In the case of a transparent conductive film, a metal film, or the like, such defects (corrosion, change in resistance value, etc.) caused by acid can also be suppressed. However, it is permissible to contain a predetermined amount of the carboxyl group-containing monomer to such an extent that the inconvenience does not occur. Specifically, in the (meth)acrylate copolymer (A), it is allowed to contain a carboxyl group-containing monomer as a monomer unit in an amount of less than 5% by mass Preferably, the carboxyl group-containing monomer is contained in an amount of 2 mass % or less, particularly preferably 0.1 mass % or less.

(Meth)acrylate copolymer (A) contains alkyl (meth)acrylate having an alkyl group of 1 to 20 carbon atoms as a monomer unit constituting the polymer, whereby better adhesion can be exhibited . Examples of alkyl (meth)acrylates having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and (meth)acrylate. n-butyl meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylate n-decyl acrylate, n-dodecyl (meth)acrylate, tetradecyl (meth)acrylate, cetyl (meth)acrylate, octadecyl (meth)acrylate, etc. . Among them, from the viewpoint of further improving adhesiveness, (meth)acrylates having 1 to 8 carbon atoms in the alkyl group are preferable, n-butyl (meth)acrylate or 2-ethyl (meth)acrylate Hexyl esters are particularly preferred. In addition, these may be used alone or in combination of two or more.

The (meth)acrylate copolymer (A) preferably contains 40% by mass or more of alkyl (meth)acrylate having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and contains 50 mass % or more is especially preferable, and 60 mass % or more is more preferable. Appropriate tackiness can be imparted to the (meth)acrylate copolymer (A) when 40 mass % or more of alkyl (meth)acrylates are contained. Furthermore, it is preferable to contain 90 mass % or less of alkyl group (meth)acrylates having 1 to 20 carbon atoms, particularly preferably 80 mass % or less, and even more preferably 70 mass % or less. By making the content of alkyl (meth)acrylate 90% by mass or less, it is possible to add (meth)acrylate A desired amount of other monomer components is introduced into the copolymer (A).

It is also preferable that the (meth)acrylate copolymer (A) contains a monomer having an alicyclic structure in the molecule (alicyclic structure-containing monomer) as a monomer unit constituting the copolymer. Since the volume of the alicyclic structure-containing monomer is large, the distance between the polymers is widened by the presence of the alicyclic structure-containing monomer in the polymer. In this way, the compound (C) becomes easy to move in the polymer, and thereby becomes easy to be exposed on the surface of the adhesive. Thereby, the function as a rework formulation based on the compound (C) can be effectively exerted, and the reworkability of the obtained adhesive can be further improved.

The carbocycle of the alicyclic structure in the alicyclic structure-containing monomer may be a saturated structure or may have an unsaturated bond partially. In addition, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as bicyclic and tricyclic. The above-mentioned alicyclic structure is polycyclic from the viewpoint of increasing the distance between the obtained (meth)acrylate copolymers (A) and effectively exerting the function of the compound (C) as a reprocessing agent. Alicyclic structure (polycyclic structure) is preferable. Furthermore, considering the compatibility of the (meth)acrylate copolymer (A) with other components, it is particularly preferable that the above-mentioned polycyclic structure is a bicyclic ring to a tetracyclic ring. Also, from the viewpoint of effectively exerting the effect of the compound (C) as a reprocessing agent as described above, the number of carbon atoms in the alicyclic structure (referring to the number of all carbon atoms forming a part of the ring, when a plurality of carbon atoms independently exist) In the case of a ring, the total number of carbon atoms is generally 5 or more, preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, but in the same manner as described above, from the viewpoint of compatibility, 15 or less is preferable, and 10 or less is particularly preferable.

Examples of the alicyclic structure include cyclohexyl bone skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclodecane skeleton Dioxane skeleton, etc.), cycloolefin skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubic alkane skeleton, blueane skeleton, oxane skeleton, spiro ring skeleton, etc. Among them, those containing dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), adamantane skeleton (carbon number of alicyclic structure: 10) or isobornyl skeleton ( The carbon number of the alicyclic structure: 7) is preferred, and the one containing an isobornyl skeleton is particularly preferred.

As the above-mentioned alicyclic structure-containing monomer, a (meth)acrylate monomer containing the above-mentioned skeleton is preferable, and specifically, cyclohexyl (meth)acrylate and dicyclopentane (meth)acrylate are mentioned. esters, adamantyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, etc., among them, the more excellent Dicyclopentyl (meth)acrylate, adamantyl (meth)acrylate or isobornyl (meth)acrylate are preferred for durability, and isobornyl (meth)acrylate is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

When the (meth)acrylate copolymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer, the (meth)acrylate copolymer (A) contains 5% by mass or more of an alicyclic structure-containing monomer The monomer of formula structure is preferable, and it is especially preferable to contain 8 mass % or more, and it is further more preferable to contain 11 mass % or more. In addition, the (meth)acrylate copolymer (A) preferably contains 40 mass % or less of an alicyclic structure-containing monomer as a monomer unit constituting the polymer, particularly preferably 30 mass % or less, and 25 mass % or less. % or less is more preferable. By making the content of the alicyclic structure-containing monomer within the above-mentioned range, the compound (C) can be effectively used as an additive. The function of the industrial preparation becomes the one with better reworkability of the obtained adhesive.

It is also preferable that the (meth)acrylate copolymer (A) contains a monomer having a nitrogen atom in the molecule (a nitrogen atom-containing monomer) as a monomer unit constituting the copolymer. By making the nitrogen atom-containing monomer exist in the polymer as a structural unit, the reaction of the acrylate copolymer (A) and the crosslinking agent (B) can be promoted, or the polarity of the adhesive can be imparted, and the adhesiveness of the adhesive itself can be improved. cohesion.

As said nitrogen atom-containing monomer, the monomer which has an amine group, the monomer which has an amide group, and the monomer which has a nitrogen-containing heterocyclic ring etc. are mentioned, Among them, the monomer which has a nitrogen-containing heterocyclic ring is preferable.

Examples of the monomer having a nitrogen-containing heterocycle include N-(meth)acryloylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acrylopyrrolidone, N-(methyl)acrylopyrrolidone, (meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-(meth)acryloylaziridine, aziridine ethyl (meth)acrylate, 2-vinylpyridine , 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N-vinylimidazole, N-vinylphthalimide, etc. Among them, N-(methyl) yl) acryl morpholine is preferred, and N-acryl morpholine is particularly preferred.

In addition, as a nitrogen atom-containing monomer other than the monomer having the aforementioned nitrogen-containing heterocycle, for example, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol ( Meth) acrylamide, N-tert-butyl (meth) acrylamide, N,N-dimethyl (meth) acrylamide, N,N-ethyl (meth) acrylamide, N ,N-Dimethylaminopropyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-phenyl (meth)acrylamide, dimethylaminopropyl (Meth)acrylamide, N-vinylcaprolactam, (meth)acrylic acid monomethylamine Ethyl (meth)acrylate, monoethylaminoethyl (meth)acrylate, (meth)acrylate monomethylaminopropyl, (meth)acrylate monoethylaminopropyl, (meth)acrylate dimethyl Amino ethyl ester, etc.

The above nitrogen atom-containing monomers may be used alone or in combination of two or more.

When the (meth)acrylate copolymer (A) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the (meth)acrylate copolymer (A) contains 1 mass % or more of the nitrogen atom-containing monomer More preferably, it is more preferable to contain 2 mass % or more, and it is further more preferable to contain 4 mass % or more. Further, the (meth)acrylate copolymer (A) preferably contains 40 mass % or less of a nitrogen atom-containing monomer as a monomer unit constituting the polymer, particularly preferably 25 mass % or less, and 14 mass % or less for further better. If the content of the nitrogen atom-containing monomer is within the above range, the cohesive force of the obtained adhesive is effectively improved.

The (meth)acrylate copolymer (A) may contain other monomers as monomeric units constituting the polymer as needed. As other monomers, monomers that do not contain reactive functional groups are preferred. Examples of such other monomers include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, ethyl acetate, benzene and the like. Ethylene etc. These may be used alone or in combination of two or more.

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

As described above, the weight average molecular weight of the (meth)acrylate copolymer (A) is 400,000 or more, preferably 450,000 or more, and particularly preferably 500,000 or more. If the weight average molecular weight of the (meth)acrylate copolymer (A) is the above On the other hand, the reworkability of the obtained adhesive and the step followability under high temperature and high humidity conditions can be well ensured. And, as described above, the weight average molecular weight is 1.3 million or less, preferably 1 million or less, and particularly preferably 900,000 or less. When the weight average molecular weight of the (meth)acrylate copolymer (A) is the above-mentioned or less, the obtained adhesive exhibits good flexibility and is excellent in initial step followability.

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

(2) Cross-linking agent (B)

When the adhesive composition P containing the crosslinking agent (B) is heated, the crosslinking agent (B) crosslinks the (meth)acrylate copolymer (A) to form a three-dimensional network structure. Thereby, the cohesive force of the adhesive agent obtained is improved, for example, even under high temperature and high humidity conditions, it becomes one which is excellent in step followability.

As said crosslinking agent (B), what is necessary is just to react with the reactive group which (meth)acrylate copolymer (A) has, For example, an isocyanate type crosslinking agent, an epoxy type crosslinking agent can be mentioned. agent, amine-based cross-linking agent, melamine-based cross-linking agent, aziridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, Metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking agent, etc. Among the above, when the reactive group of the (meth)acrylate copolymer (A) is a hydroxyl group, it is better to use an isocyanate-based crosslinking agent with excellent reactivity with the hydroxyl group. When the reactive group which the copolymer (A) has is a carboxyl group, it is preferable to use an epoxy-based crosslinking agent having excellent reactivity with the carboxyl group. Moreover, the crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound By. Examples of the polyisocyanate compound include aromatic polyisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and isophorone diisocyanate. , alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, etc., and their biuret, isocyanurate, and ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor Sesame oil, etc. as adducts with reactants containing low molecular active hydrogen compounds, etc. Among them, from the viewpoint of reactivity with hydroxyl groups, trimethylolpropane-modified aromatic polyisocyanates are preferred, and trimethylolpropane-modified toluene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are preferred. Diisocyanates are particularly preferred.

Examples of epoxy-based crosslinking 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, diglycidyl aniline, diglycidyl amine, etc. . Among them, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane is preferred from the viewpoint of reactivity with a carboxyl group.

The content of the crosslinking agent (B) in the adhesive composition P is preferably 0.01 part by mass or more, particularly preferably 0.05 part by mass or more, and 0.1 part by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A). The number of parts or more is further preferable. In addition, the content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and even more preferably 0.4 parts by mass or less. By making the content of the crosslinking agent (B) within the above-mentioned range, the obtained adhesive exhibits good cohesion, and becomes one that is more excellent in step followability under high temperature and high humidity conditions.

(3) Compound (C)

The compound (C) is a compound which has an alkylene oxide moiety and does not have or has a reactive group which reacts with the crosslinking agent (B). As described above, among the adhesives obtained from the adhesive composition P, the compound (C) functions as an excellent reprocessing agent. Specifically, since the compound (C) is a compound having an alkylene oxide moiety, the obtained adhesive exhibits excellent reworkability. Furthermore, compatibility with the (meth)acrylate copolymer (A) is ensured by the fact that the compound (C) does not have or has a reactive group that reacts with the crosslinking agent (B). In addition, at the same time, the reaction between the (meth)acrylate copolymer (A) and the crosslinking agent (B) is not hindered by the compound (C), so that a good crosslinking structure can be formed, and the obtained adhesive can exert its full potential. The cohesion of hope. Furthermore, since the compound having the above-mentioned structure is different from the surfactant, when the adhesive composition P is prepared, it is difficult to generate air bubbles, and even if it is generated, it is easy to remove. Therefore, a bubble-free adhesive layer can be easily formed.

The compound (C) preferably has a linear structure. Since the compound (C) has a linear structure, it becomes easy to move in the (meth)acrylate copolymer (A) (the cross-linked structure) during the formation of the adhesive layer such as the drying process. Thereby, the compound (C) becomes easy to be exposed on the surface of the adhesive, and effectively functions as a rework formulation, and the reworkability of the obtained adhesive becomes more excellent. In addition, in this specification, the "linear" of the "linear structure" means a substantially "linear". That is, as long as the effect of the compound (C) as a reprocessing agent can be exhibited well, the linear structure may have a branch.

It is preferable that the compound (C) is not a silicone compound, that is, a compound that does not have a siloxane bond in the molecule. If the adhesive composition P contains a silicone compound, the adhesive layer of the obtained adhesive is bonded to the adhesive layer. When the interaction between the peeling sheets becomes stronger, the peeling sheets may be re-peeled. Furthermore, the silicone compound cannot sufficiently function as a reprocessing agent.

As the alkylene oxide in the above-mentioned alkylene oxide moiety, an alkylene oxide having 2 to 4 carbon atoms is preferable, for example, ethylene oxide, propylene oxide, butylene oxide, etc. are preferably mentioned, and among them, a ring Ethylene oxide is preferred. Moreover, as a reactive group which reacts with the said crosslinking agent (B), a hydroxyl group, a carboxyl group, and an amino group are mentioned.

The compound (C) preferably has a linear structure, and preferably has a non-reactive group that does not react with the crosslinking agent (B) at both ends or at one end. The non-reactive group is preferably an alkyl group or a (meth)acryloyl group. That is, the compound (C) has a straight-chain structure and preferably has an alkyl group at both or one terminal thereof, or preferably has a (meth)acryloyl group at both or one terminal thereof. And, the compound (C) may have a linear structure, and may have an alkyl group at one terminal and a (meth)acryloyl group at the other terminal.

The number of carbon atoms in the alkyl group is preferably 1 or more. Further, the number of carbon atoms of the alkyl group is preferably 10 or less, particularly preferably 5 or less. Specifically, as the alkyl group, a methyl group, an ethyl group, a propyl group, etc. are preferable, and a methyl group is especially preferable from the viewpoint of the polarity of the compound.

The above-mentioned (meth)acryloyl group does not react with the crosslinking agent (B) and remains in the adhesive as it is. Since the compound (C) has a linear structure and has a (meth)acryloyl group at both ends or at one end thereof, the compound (C) has better compatibility with the (meth)acrylate copolymer (A). , the adhesive force and reworkability of the obtained adhesive can be stably obtained.

From the viewpoint of reworkability exhibited, it is preferable that the compound (C) has a glycol ether skeleton, among which, it has monoethylene glycol ether, diethylene glycol Those with skeletons such as alcohol ethers, triethylene glycol ethers, tetraethylene glycol ethers, and polyethylene glycol ethers are preferred.

As the compound (C), specifically, tetraethylene glycol alkyl ether, tetraethylene glycol dialkyl ether, polyethylene glycol alkyl ether, polyethylene glycol dialkyl ether, Alkoxy polyethylene glycol (meth)acrylate, polyethylene glycol di (meth)acrylate, and the like. Among the above, tetraethylene glycol dimethyl ether, polyethylene glycol methyl ether, methoxypolyethylene glycol (meth)acrylate, and polyethylene glycol dimethyl ether, from the viewpoint of reworkability exhibited. (Meth)acrylates are particularly preferred. Moreover, a compound (C) can be used individually by 1 type or in combination of 2 or more types.

The number average molecular weight of the compound (C) is preferably 100 or more, particularly preferably 200 or more, and even more preferably 300 or more. Furthermore, the number average molecular weight is preferably 2,000 or less, particularly preferably 1,500 or less, and even more preferably 1,000 or less. By making the number-average molecular weight of the compound (C) within the above-mentioned range, the compound (C) becomes easy to move in the (meth)acrylate copolymer (A) (the cross-linked structure), thereby changing. It is easy to be exposed on the surface of the adhesive, and the reworkability of the obtained adhesive is further excellent. In addition, the number average molecular weight in this specification is the standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

The content of the compound (C) in the adhesive composition P is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and 1.0 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A). The above is particularly preferred, and 1.5 parts by mass or more is further preferred. When the content of the compound (C) is more than the above, the function of the compound (C) as a rework formulation can be effectively exerted, and the reworkability of the obtained adhesive can be more excellent. In addition, the content of the compound (C) is preferably less than 10 parts by mass, particularly preferably not more than 8 parts by mass, and 5 parts by mass Parts or less are more preferable. If the content of the compound (C) is the above-mentioned or less, the adhesive force as the adhesive for displays will be more excellent.

(4) Silane coupling agent (D)

It is preferable that the adhesive composition P further contains a silane coupling agent (D). Thereby, when a glass member exists on a to-be-adhered body, the adhesiveness of the obtained adhesive agent and this glass member improves. Furthermore, even if the adherend is a plastic board, the adhesiveness between the obtained adhesive and the plastic board is also improved. Thereby, the obtained adhesive becomes more excellent in step followability under high temperature and high humidity conditions.

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

As such a silane coupling agent (D), a polymerizable unsaturated group-containing silane such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloyloxypropyltrimethoxysilane can be mentioned, for example. Silicon compounds, 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and other silicon compounds with epoxy structure, 3-mercaptopropyl Trimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane and other mercapto-containing silicon compounds, 3-aminopropyltrimethoxysilane, N-(2 -Aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino-containing silicon compounds, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these in combination with methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane , Condensates of alkyl-containing silicon compounds such as ethyl trimethoxy silane, etc. These may be used individually by 1 type, and may be used in combination of 2 or more types.

The content of the silane coupling agent (D) in the adhesive composition P is preferably 0.01 part by mass or more, particularly preferably 0.05 part by mass or more, and 0.1 part by mass relative to 100 parts by mass of the (meth)acrylate copolymer (A). The number of parts or more is further preferable. In addition, the content is preferably 1 part by mass or less, particularly preferably 0.5 part by mass or less, and even more preferably 0.3 part by mass or less.

(5) Various additives

In the adhesive composition P, various additives commonly used in acrylic adhesives, such as ultraviolet absorbers, antistatic agents, tackifiers, antioxidants, light stabilizers, softeners, fillers, refractive index, can be added as required. adjuster, etc. In addition, the polymerization solvent and the dilution solvent mentioned later shall be those which are not contained in the additive which comprises the adhesive composition P.

(6) Manufacture of adhesive composition

The adhesive composition P can be prepared by producing (meth)acrylate copolymer (A) and mixing the obtained (meth)acrylate copolymer (A), crosslinking agent (B) and compound (C), And it is manufactured by adding a silane coupling agent (D) and an additive as needed.

The (meth)acrylate copolymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a normal radical polymerization method. The polymerization system of the (meth)acrylate copolymer (A) is preferably carried out by a solution polymerization method using a polymerization initiator as necessary. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, etc. are mentioned, for example, You may use two or more types together.

As a polymerization initiator, an azo compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. As the azo compound, for example 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2 ,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile) ), 2,2'-azobis[2-(2-imidazolin-2-yl)propane], etc.

Examples of organic peroxides include benzyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-n-propyl peroxydicarbonate, (2-ethoxyethyl) peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexanol) peroxide, Dipropylene peroxide, diacetyl peroxide, etc.

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

After obtaining the (meth)acrylate copolymer (A), the crosslinking agent (B), the compound (C) and, if necessary, the silane coupling agent (D) are added to the solution of the (meth)acrylate copolymer (A) ), additives and diluting solvent, and mix them thoroughly to obtain an adhesive composition P (coating solution) diluted with a solvent. Among them, since the compound (C) used in the present embodiment is different from the surfactant, when the adhesive composition P is prepared, it is difficult to generate air bubbles, and even if it occurs, it is easy to remove. Therefore, a bubble-free adhesive layer can be easily formed.

In addition, when any one of the above components is used in a solid state, or when precipitation occurs when mixed with other components in an undiluted state, the component may be dissolved or diluted in a diluting solvent alone in advance, and then mixed with other components. Ingredient mix.

As the diluting solvent, for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, methanol, ethanol, propanol, Alcohols such as butanol, 1-methoxy-2-propanol, acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone and other ketones, ethyl acetate, butyl acetate and other esters, ethyl cellosolve Cellosolve-based solvents such as agents, etc.

The concentration and viscosity of the thus-prepared coating solution are not particularly limited as long as they are within the range that can be coated, and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P is diluted to be 10 to 60 mass %. In addition, when obtaining a coating solution, the addition of a diluent solvent or the like is not an essential condition, and the diluent solvent may not be added as long as the adhesive composition P has a coating viscosity or the like. At this time, the adhesive composition P is a coating solution in which the polymerization solvent of the (meth)acrylate copolymer (A) is directly used as a dilution solvent.

(adhesive)

The adhesive of the present embodiment is obtained by crosslinking the adhesive composition P. The crosslinking of the adhesive composition P can usually be performed by heat treatment. In addition, this heat treatment can also be combined with a drying treatment at the time of volatilizing a dilution solvent or the like from the coating film of the adhesive composition P applied to a desired object.

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

After the heat treatment, if necessary, an aging period of about 1 to 2 weeks can be provided at normal temperature (for example, 23° C., 50% RH). When the aging period is required, the adhesive is formed after the aging period has elapsed, and when the aging period is not required, the adhesive is formed after the end of the heat treatment.

By the above-mentioned heat treatment (and curing), the (meth)acrylate copolymer (A) is sufficiently cross-linked via the cross-linking agent (B), and the compound is present in the cross-linked structure and on the surface of the cross-linked structure. (C). The adhesive thus obtained maintains the performance as an adhesive for a display body, and is particularly good in step followability under high temperature and high humidity conditions and excellent in reworkability.

The lower limit of the gel fraction of the adhesive of the present embodiment is preferably 30% or more, more preferably 40% or more, and particularly preferably 50% or more. When the lower limit value of the gel fraction of the adhesive is the above-mentioned or more, the cohesive force of the adhesive is improved, and the step followability under high-temperature and high-humidity conditions is more excellent. In addition, the upper limit of the gel fraction of the adhesive of the present embodiment is preferably 90% or less, particularly preferably 85% or less, and even more preferably 80% or less. If the upper limit of the gel fraction of the adhesive is not more than the above, the adhesive will not become too hard, and the initial step followability will be more excellent. Here, the measurement method of the gel fraction of the adhesive is shown in the test example described later.

[Adhesive Sheet]

The adhesive sheet of the present embodiment has an adhesive layer for bonding one display component member and another display component component, and the adhesive layer contains the aforementioned adhesive.

The specific structure which is an example of the adhesive sheet of this embodiment is shown in FIG. 1. FIG.

As shown in FIG. 1, the adhesive sheet 1 of one embodiment is composed of two release sheets 12a, 12b; The adhesive layer 11 sandwiched by 12a, 12b. In addition, the peeling surface of the peeling sheet in this specification means that the peeling sheet has a peeling surface in the peeling sheet. The surface of the property includes both the surface to which the peeling treatment is performed and the surface that shows the peelability even if the peeling treatment is not performed.

(1) Adhesive layer

The adhesive layer 11 is composed of the above-mentioned adhesive, that is, an adhesive formed by cross-linking the adhesive composition P.

The lower limit of the thickness of the adhesive layer 11 in the adhesive sheet 1 of the present embodiment (value measured in accordance with JIS K7130) is preferably 20 μm or more, more preferably 25 μm or more, particularly preferably 30 μm or more, and further preferably 50 μm or more. good. When the lower limit of the thickness of the adhesive layer 11 is 20 μm or more, the desired adhesive force can be easily exhibited. Further, when the lower limit of the thickness of the adhesive layer 11 is 30 μm or more, sufficient step followability can be ensured with respect to the normal step of the display body constituent member.

In addition, the upper limit of the thickness of the adhesive layer 11 is preferably 500 μm or less, more preferably 400 μm or less, and particularly preferably 300 μm or less. If the upper limit of the thickness of the adhesive layer 11 is the above-mentioned or less, the workability will be good. In addition, the adhesive layer 11 may be formed by a single layer, or may be formed by laminating a plurality of layers.

(2) Peel-off sheet

The peeling sheets 12a and 12b protect the adhesive layer 11 before using the adhesive sheet 1, and are peeled off when the adhesive sheet 1 (the adhesive layer 11) is used. In the pressure-sensitive adhesive sheet 1 of the present embodiment, one or both of the release sheets 12a and 12b are not necessarily required.

As the release sheets 12a and 12b, for example, polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, and polyterephthalene films are used. ethylene formate film, polyethylene naphthalate film, polybutylene terephthalate film, urethane Ester film, vinyl acetate film, ionomer resin film, ethylene. (Meth) acrylic copolymer film, ethylene. (Meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. In addition, these crosslinked films can also be used. In addition, these laminated films may be used.

It is preferable that the peeling process is performed on the peeling surface (especially the surface contacting the adhesive layer 11) of the said peeling sheet 12a, 12b. Examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. In the release sheets 12a and 12b, it is preferable that one release sheet 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 smaller release force.

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

(3) Physical properties

(3-1) Follow rate of step difference

In the adhesive layer 11 of the adhesive sheet 1 of the present embodiment, the lower limit of the step following rate (%) represented by the following formula is preferably 20% or more, particularly preferably 25% or more, and further preferably 30% or more . In addition, the upper limit value of the step tracking rate is not particularly limited, but it is usually preferably 80% or less, and particularly preferably 70% or less.

Step follow-up rate (%) = {(After the specified durability test, the height of the step (μm) in the state of being buried without bubbles, floating, peeling, etc.) / (thickness of the adhesive layer)} × 100

In addition, the test method of the step following rate is shown in the test example mentioned later.

The adhesive layer of the adhesive sheet of this embodiment is suitable for Bonding of the display body constituent member having a level difference on one side. By setting the step following rate of the adhesive layer within the above-mentioned range, the adhesive layer can well follow the step difference of the constituent members of the display body, and the generation of air bubbles, floating, peeling, etc. in the vicinity of the step difference can also be suppressed through the durability test, whereby the The reflection loss of generated light can be suppressed. Even if the adhesive contains the compound (C), the step follow-up rate in the above-mentioned range can be achieved.

(3-2) Haze value

The haze value of the adhesive layer 11 of the adhesive sheet 1 of the present embodiment is preferably 5.0% or less, particularly preferably 3.0% or less, and even more preferably 1.0% or less. When the haze value of the adhesive layer 11 is 5.0% or less, the transparency is very high, and it is suitable for optical applications (for displays). In addition, the haze value in this specification is the value measured based on JISK7136:2000.

(3-3) Adhesion

The lower limit of the adhesive force of the adhesive sheet 1 of the present embodiment to soda lime glass is preferably 1 N/25mm or more, particularly preferably 2N/25mm or more, and further preferably 5N/25mm or more. If the adhesive force of the adhesive sheet 1 is 1 N/25 mm or more, it will be more excellent in step followability under high temperature and high humidity conditions. In addition, the upper limit of the adhesive force of the adhesive sheet 1 of the present embodiment to soda lime glass is preferably 35N/25mm or less, more preferably 30N/25mm or less, and particularly preferably 25N/25mm or less. When the adhesive force of the adhesive sheet 1 is 35 N/25 mm or less, the reworkability can be excellent. This makes it possible to easily peel off the adhesive layer from the display element constituting member even when an error in bonding to the display element constituting member occurs, thereby enabling reuse of the expensive display element constituting member.

The adhesive force in this specification basically refers to the adhesive force measured by the 180° peeling method in accordance with JIS Z0237:2009. With a width of 25 mm and a length of 100 mm, the measurement sample was attached to the adherend, pressurized at 0.5 MPa and 50°C for 20 minutes, and then left to stand for 24 hours under the conditions of normal pressure, 23°C, and 50% RH. It was obtained by measuring at a peeling speed of 300 mm/min.

(3-4) Peeling force

The lower limit of the peeling force when peeling the adhesive layer 11 (the laminate of the base material and the adhesive layer 11 ) according to the present embodiment from the release sheet 12a or 12b is preferably 30 mN/25 mm or more, particularly preferably 50 mN/25 mm or more. , 80mN/25mm or more is further preferred. If the peeling force is 30 mN/25 mm or more, unexpected peeling of the peeling sheet 12 a or 12 b from the adhesive layer 11 can be suppressed. In addition, the upper limit of the peeling force when peeling the adhesive layer 11 (the laminate of the base material and the adhesive layer 11 ) according to the present embodiment from the release sheet 12a or 12b is preferably 300 mN/25 mm or less, preferably 200 mN/25 mm or less Even better, especially below 150mN/25mm. When the peeling force is 150 mN/25 mm or less, the peeling sheet 12a or 12b can be easily peeled off from the adhesive layer 11 .

Here, the peeling force in this specification basically means the adhesive force measured by the 180-degree peeling method based on JIS Z0237:2009, and it is specifically as shown in the test example mentioned later.

(4) Manufacture of adhesive sheet

As a production example of the adhesive sheet 1, the above-mentioned coating liquid of the adhesive composition P is applied to the release surface of one release sheet 12a (or 12b), and the adhesive composition P is thermally cross-linked by heat treatment. After the coating layer is formed, the peeling surface of the other peeling sheet 12b (or 12a ) is superimposed on the coating layer. When a curing period is required, the above-mentioned coating layer becomes the adhesive layer 11 by passing through the curing period. When the aging period is not required, the above-mentioned coating layer becomes the adhesive layer 11 as it is. Thereby, the said adhesive sheet 1 can be obtained. The heat treatment and aging conditions are as described above.

As another production example of the adhesive sheet 1, the coating liquid of the above-mentioned adhesive composition P is applied to the release surface of one release sheet 12a, and heat-treated to thermally crosslink the adhesive composition P to form a coating layer to obtain a release sheet 12a with a coating layer. Then, the coating liquid of the above-mentioned adhesive composition P is applied to the release surface of the other release sheet 12b, and the adhesive composition P is thermally cross-linked by heat treatment to form a coating layer, thereby obtaining a tape coating. The release sheet 12b of the layer. And, the release sheet 12a with a coating layer and the release sheet 12b with a coating layer are bonded together in such a way that the two coating layers are mutually etched. When the curing period is required, the above-mentioned coating layer of the laminated layer becomes the adhesive layer 11 through the curing period, and when the curing period is not required, the above-mentioned coating layer of the laminated layer directly becomes the adhesive layer 11 . Thereby, the said adhesive sheet 1 can be obtained. According to this production example, even when the adhesive layer 11 is thick, stable production can be performed.

As a method for applying the coating liquid of the above-mentioned adhesive composition P, for example, a bar coating method, a blade coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, etc. can be used. .

[display body]

As shown in FIG. 2, the display body 2 of the present embodiment includes the following structures: a first display body constituting member 21 (a display body constituting member); a second display body constituting member 22 (another display body constituting member); and The adhesive layer 11 which is located between these and adheres the first display body constituent member 21 and the second display body constituent member 22 to each other.

The adhesive layer 11 in the above-mentioned display body 2 is the adhesive layer 11 of the above-mentioned adhesive sheet 1 . Adhesive layer 11 .

It is preferable that the 1st display body structure member 21 and the 2nd display body structure member 22 are hard bodies. Compared with lamination of films or between films and rigid bodies, lamination of rigid bodies by an adhesive layer is more difficult, and the yield at the time of lamination tends to decrease. Therefore, in this case, it is highly necessary to peel off the two rigid bodies so that the first display body constituting member 21 and/or the second display body constituting member 22 (especially the expensive display body module) can be reused , but when using a normal adhesive layer, it is difficult to peel off the two hard bodies. On the other hand, by using the adhesive layer 11 of the adhesive sheet 1 of the present embodiment, the two rigid bodies can be easily peeled off, and the reassembly of the first display body constituent member 21 and/or the second display body constituent member 22 can be realized. use.

In addition, the "hard body" in this specification means the elastic modulus measured based on JIS K7127:1999 which is 10 GPa or more. The rigid body may comprise a single layer or a single member, or may comprise a plurality of layers or a plurality of members. In the latter case, as long as it satisfies the above-mentioned elastic modulus as an object including a plurality of layers or a plurality of members, even if some of the layers or members of the object do not satisfy the above-mentioned elastic modulus, the object can also be called a rigid body.

It is preferable that the first display body constituent member 21 (one display body constituent member) has a level difference at least on the surface on the side to be bonded. In the display body 2 of this embodiment, the surface of the first display body constituent member 21 on the adhesive layer 11 side has a level difference, specifically, a level difference based on the printing layer 3 . The adhesive layer 11 of the adhesive sheet 1 of the present embodiment is excellent in step followability (initial step followability and step followability under high temperature and high humidity conditions), so the adhesive sheet 1 is attached to the first display body constituent member 21 When the adhesive layer 11 is easy to follow the level difference, it can be suppressed from being attached to the level difference. Near gaps, floating, etc. In addition, when left in this state under high temperature and high humidity conditions, generation of bubbles, floating, peeling, etc. in the vicinity of the level difference can also be suppressed.

As the display body 2, a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (organic EL) display, electronic paper, etc. are mentioned, for example, and a touch panel may be sufficient. In addition, the display body 2 may be a member constituting a part of these.

The first display body constituent member 21 may be a glass plate, a plastic plate, or the like, and is preferably a protective panel composed of a laminate or the like including these. At this time, the printed layer 3 is generally formed in a frame shape on the side of the adhesive layer 11 in the first display body constituent member 21 .

It does not specifically limit as said glass plate, For example, chemically strengthened glass, alkali-free glass, quartz glass, soda lime glass, barium-containing glass are mentioned. Strontium glass, aluminosilicate glass, lead glass, borosilicate glass, barium borosilicate glass, etc. The thickness of the glass plate is not particularly limited, but is usually 0.1 to 5 mm, preferably 0.2 to 2 mm.

It does not specifically limit as said plastic board, For example, an acrylic board, a polycarbonate board, etc. are mentioned. The thickness of the plastic plate is not particularly limited, and is usually 0.2 to 5 mm, preferably 0.4 to 3 mm.

In addition, various functional layers (transparent conductive film, metal layer, silicon oxide layer, hard coat layer, anti-glare layer, etc.) may be provided on one or both surfaces of the glass plate or plastic plate, and optical members may be laminated. Also, the transparent conductive film and the metal layer may be patterned.

The second display body constituting member 22 is an optical member to be attached to the first display body constituting member 21, a display body module (for example, a liquid crystal (LCD) module modules, light emitting diode (LED) modules, organic electroluminescence (organic EL) modules, etc.), optical components that are part of display modules, or laminates including display modules are preferred.

Examples of the above-mentioned optical members include scattering prevention films, polarizers (polarizing films), polarizers, retardation films (retardation films), viewing angle compensation films, brightness enhancement films, contrast enhancement films, liquid crystal polymer films, Diffusion film, semi-transmissive reflection film, transparent conductive film, etc. Examples of the anti-scattering film include a hard coat film formed by forming a hard coat layer on one surface of a base film, and the like.

The material constituting the printed layer 3 is not particularly limited, and known materials for printing can be used. The thickness of the printed layer 3, that is, the lower limit of 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. By making the lower limit value more than the above, it is possible to sufficiently ensure the concealment from the observer's side from which the wiring and the like cannot be seen. Further, 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. By making the upper limit value not more than the above, it is possible to prevent deterioration of the step followability of the adhesive layer 11 with respect to the printed layer 3 .

When manufacturing the above-mentioned 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 attached to the side where the printed layer 3 of the first display body constituent member 21 exists. face. At this time, since the adhesive layer 11 is excellent in step followability, it is possible to suppress generation of gaps or floating in the vicinity of the step formed by the print layer 3 .

Thereafter, 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 is formed with the second display body The members 22 are bonded together to obtain the display body 2 . Moreover, as another example, the bonding order of the 1st display body structure member 21 and the 2nd display body structure member 22 may be replaced. At this time, even when the bonding position of the second display body structuring member 22 is deviated, the adhesive layer 11 can be easily peeled off from the second display body structuring member 22 because of its excellent reworkability. and the first display body constitutes a layered body of the member 21 . In particular, these rigid bodies can be easily peeled off from each other. Thereby, at least the second display body configuration member 22 can be reused.

In the above-mentioned display body 2, the adhesive layer 11 is also excellent in step followability under high temperature and high humidity conditions. Therefore, when the display body 2 is placed under high temperature and high humidity conditions (eg, 85°C, 85% RH), for example, the The generation of air bubbles, floating, peeling, etc. in the vicinity of the level difference 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 of the requirements disclosed in the above-described embodiments also includes all design changes and equivalents 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, and a desired optical member may be laminated instead of the release sheets 12a and/or 12b. In addition, the first display body constituent member 21 may have steps other than the printed layer 3 . Furthermore, not only the first display body configuration member 21 but also the second display body configuration member 22 may be one having a step on the adhesive layer 11 side.

【Example】

Hereinafter, 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)acrylate copolymers

(Meth)acrylate copolymerization prepared by copolymerizing 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of isobornyl acrylate, 5 parts by mass of N-acryloylmorpholine, and 15 parts by mass of 2-hydroxyethyl acrylate Object (A). As a result of measuring the molecular weight of this (meth)acrylate copolymer (A) by the method mentioned later, the weight average molecular weight (Mw) was 500,000.

2. Preparation of adhesive composition

100 parts by mass of (meth)acrylate copolymer (A) obtained in the above-mentioned process 1 (solid content conversion value; the same below), trimethylolpropane-modified toluene diisocyanate ( Soken Chemical & Engineering Co., Ltd. manufacture, product name "L-45") 0.2 mass part, as compound (C) tetraethylene glycol dimethyl ether (TOHO Chemical Industry Co., Ltd. manufacture, product name " 0.5 parts by mass of 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM403") as a silane coupling agent (D) By mixing, stirring well, and diluting with methyl ethyl ketone, the coating solution of the adhesive composition with a solid content concentration of 45 mass % was obtained.

3. Manufacture of adhesive sheet

On the peel-treated side of a heavy-peel release sheet (manufactured by LINTEC Corporation, product name "SP-PET752150") obtained by peeling one side of a polyethylene terephthalate film with a silicone-based peeling agent, The coating solution of the obtained adhesive composition was coated by a knife coater. And the coating layer was heat-processed at 90 degreeC for 1 minute, and the coating layer was formed.

Next, in such a way that the release treated surface of the light release type release sheet is in contact with the coating layer, the coating layer on the heavy release type release sheet obtained in the above is pasted with the polyethylene terephthalate with a silicone-based release agent. The light release type release sheet (manufactured by LINTEC Corporation, product name "SP-PET382120") in which one side of the ester film was peeled was aged for 7 days under the conditions of 23° C. and 50% RH, thereby producing a sheet having a thickness of The adhesive sheet of the adhesive layer of 25 μm, that is, the adhesive sheet (first adhesive sheet) of the structure including the heavy release type release sheet/adhesive layer (thickness: 25 μm)/light release type release sheet. In addition, the solid content concentration of the coating solution of the adhesive composition was changed to 55% by mass, and the thickness of the adhesive layer was changed to 50 μm, and an adhesive layer having a thickness of 50 μm was produced in the same manner as above. A sheet, that is, an adhesive sheet (second adhesive sheet) comprising a structure of a heavy release type release sheet/adhesive layer (thickness: 50 μm)/light release type release sheet. In addition, the thickness of the adhesive layer is a value measured using a constant pressure thickness measuring device (manufactured by TECLOCK Corporation, product name "PG-02") in accordance with JIS K7130.

Here, Table 1 shows each compounding (solid content conversion value) of the adhesive composition when the (meth)acrylate copolymer (A) is 100 parts by mass (solid content conversion value). In addition, the details of the abbreviations etc. described in Table 1 are as follows.

[(Meth)acrylate Copolymer (A)]

2EHA: 2-ethylhexyl acrylate

IBXA: Isobornyl Acrylate

ACMO: N-acrylomorpholine

HEA: 2-hydroxyethyl acrylate

MMA: methyl methacrylate

BA: n-butyl acrylate

MA: methyl acrylate

AA: Acrylic

[Crosslinking agent (B)]

TDI: Trimethylolpropane-modified toluene diisocyanate (manufactured by Soken Chemical & Engineering Co., Ltd., product name "L-45")

XDI: Trimethylolpropane-modified xylene diisocyanate (manufactured by Soken Chemical & Engineering Co., Ltd., product name "TD-75")

Epoxy: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC., product name "TETRAD-C")

[Compound (C)]

Haisorubu MTEM: Tetraethylene glycol dimethyl ether (manufactured by TOHO Chemical Industry Co., Ltd., product name "Haisorubu MTEM")

PEGME: polyethylene glycol methyl ether (manufactured by ALDRICH, number average molecular weight 550)

A-400: polyethylene glycol diacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "A-400", number average molecular weight 400)

M-130G: Methoxy polyethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., product name "M-130G", number average molecular weight 550)

KF6000: Reactive silicone oil modified with methanol at both ends (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KF6000")

KF2012: Reactive silicone oil modified with methacrylic acid at one end (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KF2012")

KF8010: Reactive silicone oil modified with amine groups at both ends (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KF8010")

PEG (1000): polyethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., number average molecular weight 1000)

[Examples 2 to 22, Comparative Examples 1 to 5]

The type and ratio of each monomer constituting the (meth)acrylate copolymer (A), the weight average molecular weight (Mw) of the (meth)acrylate copolymer (A), the type of the crosslinking agent (B), and the Except that the compounding amount, the type and compounding amount of the compound (C), and the compounding amount of the silane coupling agent (D) were changed as shown in Table 1, adhesive sheets (the first adhesive sheet and the second adhesive sheet) were produced in the same manner as in Example 1. 2 adhesive sheets).

[Test Example 1] (Evaluation of defoaming properties)

The coating solutions of the adhesive compositions prepared in Examples and Comparative Examples were stirred for 15 minutes at normal temperature and 1500 rpm using a high-speed disperser (manufactured by PRIMIX Corporation, product name "HOMOGENIZING DISPER 2.5"). Next, using a desiccator (manufactured by AS ONE Corporation, product name "Stainless Steel Vacuum Dryer DVS-310"), at room temperature, vacuum degassing was performed for 20 minutes on a scale of -0.06 MPa on a vacuum gauge. The coating solution in this state was visually confirmed, and it was judged that the defoaming property was good (◯) when the air bubbles were completely removed, and the defoaming property was poor (×) when the air bubbles were not removed. The results are shown in Table 2.

[Test Example 2] (Measurement of gel fraction)

The adhesive sheets (first adhesive sheets) obtained in the examples and comparative examples were cut to a size of 80 mm × 80 mm, and the adhesive layer was wrapped in a polyester mesh (mesh size 200), and the Take its mass and subtract the mass of the net alone to calculate the mass of the adhesive itself. Let the mass at this time be M1.

Next, at room temperature (23° C.), the adhesive wrapped in the above polyester mesh was immersed in ethyl acetate for 24 hours. Then, the adhesive was taken out, air-dried for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50%, and also dried in an oven at 80° C. for 12 hours. After drying, the mass of the adhesive itself is calculated by taking its mass with a precision balance and subtracting the mass of the above-mentioned net alone. Let the mass at this time be M2. The gel fraction (%) is represented by (M2/M1)×100. The results are shown in Table 2.

[Test Example 3] (Measurement of haze value)

For the adhesive layers of the adhesive sheets (first adhesive sheets) obtained in Examples and Comparative Examples, a haze meter (manufactured by NIPPON DENSHOKU INDUSTRIES Co., LTD., product name "NDH-2000" was used in accordance with JIS K7136:2000). ”) to measure the haze value (%). The results are shown in Table 2.

[Test Example 4] (Measurement of Adhesion)

The light peeling type release sheet was peeled off from the adhesive sheets (first and second adhesive sheets) obtained in Examples and Comparative Examples, and the exposed adhesive layer was attached to a polyterephthalate having an easily adhesive layer. An easy-bonding layer of ethylene formate (PET) film (manufactured by TOYOBO CO., LTD., product name "PET A4300", thickness: 100 μm) was used to obtain a laminate of release sheet/adhesive layer/PET film. The obtained laminate was cut into a width of 25 mm and a length of 100 mm, and this was used as a sample.

In an environment of 23° C. and 50% RH, a heavy release type release sheet was peeled from the above-mentioned sample, and the exposed adhesive layer was attached to an alkali-free glass (manufactured by Corning Incorporated, product name “Eagle XG”), The pressure was applied at 0.5 MPa and 50°C for 20 minutes in an autoclave manufactured by Kurihara Manufactory Inc. After that, it was left to stand for 24 hours at 23°C and 50% RH. Then, using a universal tensile tester (manufactured by ORIENTEC Co., LTD., product name "Tensilon UTM-4-100"), the adhesive force (N/25mm) was measured under the conditions of a peeling speed of 300 mm/min and a peeling angle of 180 degrees. . Conditions other than those described here were measured in accordance with JIS Z 0237:2009. The results are shown in Table 2.

[Test Example 5] (Measurement of peeling force)

Samples were produced in the same manner as in Test Example 3 about the adhesive sheets (first adhesive sheets) obtained in Examples and Comparative Examples. The release sheet side of this sample was attached to a stainless steel plate using a double-sided tape, and was fixed to a universal tensile tester (manufactured by ORIENTEC Co., LTD., product name "Tensilon UTM-4-100"). Under the conditions of temperature of 23°C and 50% RH, according to JIS Z 0237:2009, the PET film of the sample was stretched in the 180° direction at a stretching speed of 300 mm/min, and the lamination of the PET film and the adhesive layer was measured by peeling off the release sheet. The force at the time of body was taken as the peeling force (mN/25mm). The results are shown in Table 2.

[Test Example 6] (Evaluation of reworkability based on residual glue)

The measurement of the adhesive force based on Test Example 3 was performed, and after peeling off the sample adhesive sheet (first adhesive sheet), the area of the adhesive residue on the surface of the alkali-free glass (the adhesive bonding surface) as the adherend was measured. , and the reworkability (room temperature) was evaluated according to the following criteria. The results are shown in Table 2.

○...No glue residue at all.

△... There is adhesive residue in an area of less than 30% of the bonding area.

×... There is adhesive residue in an area of 30% or more of the bonding area.

Then, as shown in Test Example 3, the sample adhesive sheet (first adhesive sheet) was attached to the alkali-free glass, pressurized, and then left to stand for 24 hours under the conditions of 23° C. and 50% RH, and then, at 60° C. Placed under the conditions of ℃ and 90%RH 24 hours (promoting conditions). Then, the pressure-sensitive adhesive sheet (first pressure-sensitive adhesive sheet) was peeled off by the method shown in Test Example 3, and the reworkability (after accelerated conditions) was evaluated on the basis of the above. The results are shown in Table 2.

[Test Example 7] (Measurement of step follow-up rate)

UV-curable ink (Teikoku Printing Inks Mfg. Co., Ltd.) was screen-printed on the surface of a glass plate (manufactured by NSG Precision Co, Ltd., product name "Corning Glass EAGLE XG", length 90 mm x width 50 mm x thickness 0.5 mm). . manufactured, product name "POS-911 ink"), so that the coating thickness is 5 μm, 10 μm, 15 μm and 20 μm any one of the frame shape (outline: length 90mm × width 50mm, width 5mm). Next, ultraviolet rays (80W/cm ² , two metal halide lamps, lamp height of 15 cm, belt speed of 10 to 15 m/min) were irradiated to harden the above-mentioned ultraviolet-curable ink printed, thereby producing a A glass plate with a level difference (height of the level difference: any of 5 μm, 10 μm, 15 μm, and 20 μm).

The light release type release sheet was peeled off from the second pressure-sensitive adhesive sheet (thickness of the pressure-sensitive adhesive layer: 50 μm) obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was attached to a polyterephthalate having an easily adhesive layer. An easy-bonding layer of an ethylene formate film (manufactured by TOYOBO Co., Ltd., product name "PET A4300", thickness: 100 μm). Next, the heavy release type release sheet is peeled off, and the adhesive layer is peeled off. Then, the above-mentioned laminated body was plastic-sealed on each glass plate with a step difference so that the entire printed surface of the frame shape was covered with an adhesive layer using a plastic sealing machine (manufactured by FUJIPLA Inc., product name "LPD3214"), and this was used for evaluation. sample.

The obtained samples for evaluation were subjected to autoclave treatment at 50°C and 0.5 MPa for 30 minutes, and then left to stand at normal pressure, 23°C, and 50% RH for 24 hours. Then, under the high temperature and high humidity conditions of 85 ° C and 85% RH, The tube was left for 72 hours (endurance test), after which the step followability was evaluated. The level difference followability was judged by whether the printing level difference was completely filled with the adhesive layer. When air bubbles, floating, peeling, etc. were observed at the interface between the printing level difference and the adhesive layer, it was judged that the printing level difference could not be followed. Here, the step followability was evaluated as a step follow rate (%) represented by the following formula. The results are shown in Table 2.

Step follow-up rate (%)={(After the durability test, the height of the step after filling without air bubbles, floating, peeling, etc. (μm))/(The thickness of the adhesive layer: 50μm)}×100

As can be seen from Table 2, the pressure-sensitive adhesive sheets obtained in the examples have appropriate adhesive force and less adhesive residue when peeled from the adherend, so they are excellent in reworkability. In addition, the adhesive sheets obtained in the examples have sufficient peeling force and are also excellent in step followability (under high temperature and high humidity conditions).

【Industrial Availability】

The adhesive sheet of the present invention can be suitably used, for example, for bonding a protective panel having a level difference to a desired display body constituent member.

1‧‧‧Adhesive Sheet

11‧‧‧Adhesive layer

12a‧‧‧Peeling sheet

12b‧‧‧Peeling sheet

Claims (10)

An adhesive sheet, which has an adhesive layer for attaching a display component and another display component, wherein the adhesive layer is an adhesive formed by cross-linking an adhesive composition; wherein the above The step-difference follow-up rate of the adhesive layer is 20% or more; wherein the adhesive composition contains: (meth)acrylate copolymer (A); and a crosslinking agent (B), which makes the (meth)acrylate copolymer (A) crosslinking; and compound (C), the (meth)acrylate copolymer (A) containing a reactive group-containing monomer having a reactive group in the molecule that reacts with the crosslinking agent (B) , but does not contain a carboxyl group-containing monomer, as a monomer unit constituting the polymer, and has a weight-average molecular weight of 400,000 or more and 1.3 million or less, the aforementioned compound (C) has an alkylene oxide moiety, and does not have or have a The reactive group in which the aforementioned crosslinking agent (B) reacts. The adhesive sheet according to claim 1, wherein the compound (C) has a linear structure and has an alkyl group at both ends or at one end. The adhesive sheet according to claim 1, wherein the compound (C) has a linear structure and has (meth)acryloyl groups at both ends or at one end. The adhesive sheet according to item 1 of the scope of the application, wherein relative to the aforementioned (A 100 parts by mass of acrylate copolymer (A), containing 0.2 parts by mass or more and less than 10 parts by mass of the aforementioned compound (C). The adhesive sheet according to claim 1, wherein the (meth)acrylate copolymer (A) contains an alicyclic structural monomer as a monomer unit constituting the polymer. The adhesive sheet according to claim 1, wherein the one display body constituting member and the aforesaid other display body constituting member are rigid bodies. The adhesive sheet according to claim 1, wherein the above-mentioned one display body constituent member has a level difference at least on the surface of one side to be attached. The pressure-sensitive adhesive sheet according to claim 1, wherein the thickness of the pressure-sensitive adhesive layer is 20 μm or more and 500 μm or less. The adhesive sheet according to claim 1, wherein the adhesive sheet comprises two peeling sheets, and the adhesive layer is sandwiched by the peeling sheets so as to be in contact with the peeling surfaces of the two peeling sheets. A display body, comprising: a display body constituting member; another display body constituting member; The layer is the adhesive layer of the adhesive sheet described in the first item of the patent application scope.

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