TWI755367B - Adhesive sheet and display body - Google Patents

Abstract

The present invention provides an adhesive sheet and a display body in which the adhesive layer is excellent in both step followability and anti-foaming property, and has good processability. The adhesive sheet of the present invention is an adhesive sheet (1) comprising an adhesive layer (2), wherein the adhesive layer 2 comprises: a first adhesive layer (21), which is an outer layer on one surface side; a second adhesive layer ( 22), which is the outer layer on the other surface side: and the 3rd adhesive layer (23), which is located between the 1st adhesive layer (21) and the 2nd adhesive layer (22) as an intermediate layer, and constitutes the first adhesive layer (22). 1 The storage elastic modulus (G') at 23°C of the adhesive of the adhesive layer (21) and the adhesive constituting the second adhesive layer (22) are respectively 0.1 MPa or more, and the third adhesive layer ( 23) It is composed of an active energy ray-curable adhesive, and the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer (21) and the second adhesive layer (22) The storage elastic modulus (G') at 23°C of the adhesive was lower than the storage elastic modulus (G') at 23°C before curing of the active energy ray-curable adhesive.

Description

Adhesive sheet and display body

The present invention relates to an adhesive sheet suitable 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 smart phones or tablet computers include displays using display modules, which are usually called touch panels. The aforementioned display modules have liquid crystal elements, light emitting diodes (LED elements), and Electroluminescence (organic EL) elements, etc.

In the above-mentioned display, a protective panel is usually provided on the surface side of the display module. With the reduction in thickness and weight of electronic devices, the above-mentioned protective panels have been changed from conventional glass plates to plastic plates such as acrylic plates and polycarbonate plates.

Here, 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 fill the protective panel and the The gap between the display modules can improve the picture quality of the display. 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 will float in the vicinity of the step, thereby causing a reflection loss of 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.

In the invention disclosed in Patent Document 1, it is intended to improve step followability by lowering the storage elastic modulus (G') at room temperature in the adhesive layer. However, if the storage elastic modulus (G') at normal temperature is lowered as described above, the storage elastic modulus (G') at high temperature is excessively lowered, causing a problem under durable conditions. For example, when high-temperature and high-humidity conditions are applied, air bubbles are generated near the level difference, or bubbles, floating, peeling, etc., are generated due to degassing from the plastic plate used as the protective panel. On the other hand, when the adhesive layer is hardened in order to improve the anti-foaming property, the step followability decreases.

In addition, when the storage elastic modulus (G') of the adhesive layer is lowered as described above, the film strength of the adhesive layer is lowered and the workability is deteriorated. For example, when punching the adhesive sheet, etc., the adhesive overflows from the cut surface and causes the adhesive to adhere to the blade and the like.

On the other hand, in order to solve the above-mentioned problems of step followability and workability, Patent Document 2 discloses an adhesive sheet in which an adhesive layer is constituted by two or more layers, and the storage shear elastic modulus of the surface layer is compared with that of the surface layer. storage in the middle layer The shear modulus of elasticity was set higher, and the indentation hardness of the entire sheet was set within a predetermined range.

【Prior technical literature】 【Patent Literature】

Patent Document 1: Japanese Patent Laid-Open No. 2010-97070

Patent Document 2: Japanese Patent Laid-Open No. 2012-184390

However, in the adhesive sheet of Patent Document 2, the storage shear elastic modulus of the surface layer is low, so there is a problem of blistering when it is attached to a protective panel made of a plastic sheet and placed under high temperature and high humidity conditions.

The present invention has been made in view of such a situation, and an object of the present invention is to provide an adhesive sheet and a display body in which the adhesive layer is excellent in both step followability and anti-foaming property, and has good processability.

In order to achieve the above object, firstly, the present invention provides an adhesive sheet, which includes an adhesive layer, and is characterized in that: the aforementioned adhesive layer includes: a first adhesive layer, which is an outer layer on one surface side; a second adhesive layer , which is the outer layer on the other surface side; and a third adhesive layer, which serves as an intermediate layer between the first adhesive layer and the second adhesive layer, and constitutes the adhesive of the first adhesive layer and The storage elastic modulus (G') at 23° C. of the adhesive constituting the second adhesive layer is respectively 0.1 MPa or more, and the third adhesive layer is composed of an active energy ray-curable adhesive. 1 The adhesive of the adhesive layer Compared with the storage elastic modulus (G') at 23°C and the storage elastic modulus (G') at 23°C of the adhesive constituting the second adhesive layer, the aforementioned active energy ray-curable adhesive The storage elastic modulus (G') at 23°C before hardening of the agent was lower (Invention 1).

Second, the present invention provides an adhesive sheet, which includes an adhesive layer, and is characterized in that: the aforementioned adhesive layer includes: a first adhesive layer, which is an outer layer on one surface side; a second adhesive layer, which is another The outer layer on the surface side; and the third adhesive layer, which is located between the first adhesive layer and the second adhesive layer as an intermediate layer, and constitutes the first adhesive layer. The adhesive and the second adhesive The 100% modulus of the adhesive of the layers is 60 kPa or more, the third adhesive layer is composed of an active energy ray-curable curable adhesive, and the 100% modulus and composition of the adhesive constituting the first adhesive layer Compared with the 100% modulus of the adhesive of the second adhesive layer, the 100% modulus before curing of the above-mentioned active energy ray-curable curable adhesive is lower (Invention 2).

According to the above inventions (Invention 1, Invention 2), the adhesive layer includes a storage elastic modulus (G') before hardening or a third adhesive layer with a lower 100% modulus as an intermediate layer, whereby the adhesive layer The initial step difference followability is excellent, and the storage elastic modulus (G') or 100% modulus of the first adhesive layer and the second adhesive layer as the outer layer are high, and the third adhesive layer is activated by active energy rays. It is hardened by irradiation, thereby excellent in step followability even under high temperature and high humidity conditions. In addition, among the adhesive layers, the storage elastic modulus (G') or 100% modulus of the first adhesive layer and the second adhesive layer as outer layers are high, and the third adhesive layer is activated by active energy rays. irradiated and hardened, thereby becoming one with excellent anti-foaming properties . Moreover, in the adhesive layer, the first adhesive layer and the second adhesive layer with higher storage elastic modulus (G') or 100% modulus are used as outer layers, and the storage elastic modulus (G') before hardening is used as the outer layer. ') or the third adhesive layer with a lower 100% modulus as an intermediate layer, thereby reducing the storage elastic modulus (G') before hardening or the cross-sectional area of the adhesive layer with a lower 100% modulus, thereby Become one with good workability.

In the above inventions (Inventions 1 and 2), the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are active energy ray non-curable adhesives (Invention 3).

In the above inventions (Inventions 1 to 3), the ratio of the total thickness of the first adhesive layer and the second adhesive layer to the thickness of the third adhesive layer is preferably 0.3 or more and 5 or less (Invention 4) .

In the above inventions (Inventions 1 to 4), the total thickness of the adhesive layer is preferably 50 μm or more and 300 μm or less (Invention 5).

In the above-mentioned inventions (Inventions 1 to 5), it is preferable to bond one display element constituting member and another display element constituting member having a level difference on at least one of the side surfaces to be attached (Invention 6).

In the above inventions (Inventions 1 to 6), the adhesive sheet includes two peeling sheets, and the adhesive layer is preferably sandwiched between the two peeling sheets so as to be in contact with the peeling surfaces of the two peeling sheets (Invention). 7).

Third, the present invention provides a display body, which includes: a display body constituting member having a level difference at least on the surface of one side to be bonded; another display body constituting member; and an adhesive layer for forming the aforementioned one display body The member and the other display body constituting member are attached to each other, and it is characterized in that: the adhesive layer is an adhesive formed by hardening the adhesive layer of the above-mentioned adhesive sheet (inventions 1 to 7). agent layer (Invention 8).

The adhesive sheet of the present invention and the adhesive layer of the display body are excellent in both step followability and anti-foaming property, and have good processability.

1‧‧‧Adhesive Sheet

2‧‧‧Adhesive layer

21‧‧‧First Adhesive Layer

22‧‧‧Second adhesive layer

23‧‧‧The third adhesive layer

31, 32‧‧‧Peeling sheet

4‧‧‧Display

51‧‧‧First Display Body Components

52‧‧‧Second display body components

6‧‧‧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 Sheet]

FIG. 1 shows a cross-sectional view of the adhesive sheet according to one embodiment of the present invention.

As shown in FIG. 1 , the adhesive sheet 1 of this embodiment is composed of two release sheets 31 , a release sheet 32 and an adhesive layer 2 , and the adhesive layer 2 is composed of two release sheets 31 and 32 . The two peeling sheets 31 and 32 are sandwiched between the two peeling sheets 31 and 32 in such a way that the peeling surfaces meet. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peeling property in a peeling sheet, and includes any of the surface which peeling process was performed, and the surface which shows peeling property even if it does not perform peeling process.

The adhesive layer 2 in the present embodiment includes a first adhesive layer 21 which is an outer layer on one surface side (the release sheet 31 side), and a second adhesive layer 22 which is the other surface side (the release sheet 32 side). ); and a third adhesive layer 23, which is located between the first adhesive layer 21 and the second adhesive layer 22 as an intermediate layer. In this embodiment, the first adhesive layer 21 and the second adhesive layer 22 are the outermost layers of the adhesive layer 2, respectively, and the first adhesive layer 21 and the release sheet 31 are the outermost layers, respectively. The peeling surfaces are in contact with each other, and the second adhesive layer 22 is in contact with the peeling surfaces of the peeling sheet 32, but it is not limited to this.

The storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 in the present embodiment is 0.1 MPa or more, respectively. In addition, the third adhesive layer 23 is formed of an active energy ray-curable adhesive. Furthermore, with the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer 21 and the storage elastic modulus at 23°C of the adhesive constituting the second adhesive layer 22 (G'), the storage elastic modulus (G') at 23°C before hardening (before hardening by active energy ray irradiation) of the active energy ray-curable adhesive is set to be lower (above , the first selectivity condition).

Alternatively, the 100% modulus of the adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 in the present embodiment are each 60 kPa or more. In addition, the third adhesive layer 23 is formed of an active energy ray-curable adhesive. And compared with the 100% modulus of the adhesive constituting the first adhesive layer 21 and the 100% modulus of the adhesive constituting the second adhesive layer 22, the pre-curing ( The 100% modulus based on active energy ray irradiation (before curing) is set to be lower (above, the second selective condition).

The adhesive layer 2 in the present embodiment has the above-mentioned three-layer structure, and each of the adhesive layer 21 , the adhesive layer 22 , and the adhesive layer 23 satisfies the above-mentioned necessary conditions, thereby achieving both the step followability and the anti-foaming property. It was excellent in all aspects, and the workability was good. That is, the adhesive layer 2 in this embodiment includes a storage elastic modulus (G') before hardening or a third adhesive layer 23 with a lower 100% modulus as an intermediate layer, whereby the The initial step difference followability is excellent. Further, make The storage elastic modulus (G') or the 100% modulus of the first adhesive layer 21 and the second adhesive layer 22 of the outer layer are higher, and the third adhesive layer 23 is cured by the irradiation of active energy rays, As a result, step followability is excellent even under high temperature and high humidity conditions. For example, when the pressure-sensitive adhesive sheet of the present embodiment is attached to a display body constituent member having a level difference, it is possible to suppress generation of gaps, floating, and the like in the vicinity of the level difference. In addition, even if it is left in this state for 72 hours under high temperature and high humidity conditions, for example, 85°C, 85% RH, generation of bubbles, floating, peeling, etc. in the vicinity of the level difference can be suppressed. Moreover, in the adhesive layer 2 in the present embodiment, the storage elastic modulus (G') or the 100% modulus of the first adhesive layer 21 and the second adhesive layer 22 as outer layers are high, and the third adhesive The agent layer 23 is cured by irradiation with active energy rays, and thereby becomes one that is excellent in anti-foaming properties. For example, even if the display body (display) obtained by using the adhesive sheet 1 of the present embodiment is placed under high temperature and high humidity conditions, for example, 85° C., 85% RH conditions for 72 hours, and the display body composed of a plastic plate or the like is left for 72 hours. When degassing occurs in the body constituting member, the generation of bubbles, floating, and peeling at the interface between the adhesive layer and the display body constituting member can also be suppressed. Furthermore, in the adhesive layer 2 in the present embodiment, the first adhesive layer 21 and the second adhesive layer 22 with higher storage elastic modulus (G') or 100% modulus are used as outer layers, and the pre-hardening The third adhesive layer 23 with a lower storage elastic modulus (G') or 100% modulus is used as an intermediate layer. Thereby, the cross-sectional area of the adhesive layer portion having a lower storage elastic modulus (G') or 100% modulus in the entire adhesive layer 2 before hardening can be reduced, thereby achieving good workability. Therefore, for example, when the pressure-sensitive adhesive sheet 1 is punched out, problems such as the adhesive overflowing from the cutting surface and the adhesive adhering to the blade can be suppressed.

As described above, as the first selective condition, the first adhesive is constituted The storage elastic modulus (G') at 23°C of the adhesive of the layer 21 and the adhesive constituting the second adhesive layer 22 is respectively 0.1 MPa or more, preferably 0.12 MPa or more, and particularly preferably 0.14 MPa or more . Further, the storage elastic modulus (G') is preferably 0.5 MPa or less, particularly preferably 0.25 MPa or less, and further preferably 0.18 MPa or less. The storage elastic modulus (G') is 0.5 MPa or less, whereby the step followability of the adhesive layer 2 can be kept high. In addition, the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer 21 and the storage elastic modulus (G') at 23°C of the adhesive constituting the second adhesive layer 22 G') may be the same or different.

Further, as the first selective condition, the storage elastic modulus (G') at 23° C. of the adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 at 23° C. The storage elastic modulus (G') at 23° C. before curing of the active energy ray-curable adhesive constituting the third adhesive layer 23 is set as lower. As a specific value, the storage elastic modulus (G') is preferably 0.10 MPa or less, particularly preferably 0.09 MPa or less, and further preferably 0.08 MPa or less. Thereby, the adhesive bond layer 2 can be made the one which is more excellent in the step followability. Further, the storage elastic modulus (G') is preferably 0.01 MPa or more, particularly preferably 0.03 MPa or more, and further preferably 0.06 MPa or more. Thereby, the adhesive bond layer 2 can be made into one whose workability is more favorable. In addition, the measurement method of the above-mentioned storage elastic modulus (G') is shown in the test example described later.

Here, the storage elastic modulus (G') at 23° C. after curing of the active energy ray-curable adhesive constituting the third adhesive layer 23 (after curing by active energy ray irradiation) is 0.1 MPa or more is better, 0.11MPa The above is particularly preferred, and 0.12 MPa or more is further preferred. Thereby, the adhesive bond layer 2 can be made the one which is more excellent in the anti-foaming property and the step followability under high temperature and high humidity conditions. On the other hand, the storage elastic modulus (G') is preferably 0.5 MPa or less, particularly preferably 0.3 MPa or less, and further preferably 0.18 MPa or less. Thereby, the adhesive force of the 3rd adhesive bond layer 23, especially the adhesive force with respect to the 1st adhesive bond layer 21 and the 2nd adhesive bond layer 22 can be kept high.

In addition, with the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer 21 and the storage elastic modulus at 23°C of the adhesive constituting the second adhesive layer 22 Compared with (G'), the storage elastic modulus (G') at 23°C after hardening of the active energy ray-curable adhesive constituting the third adhesive layer 23 may be smaller or larger, and both can also be the same. Among these, the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer 21 and the storage elasticity at 23°C of the adhesive constituting the second adhesive layer 22 It is preferable that the storage elastic modulus (G') at 23 degreeC after hardening of the active energy ray-curable adhesive which comprises the 3rd adhesive layer 23 is larger than the modulus (G'). As a result, the adhesive layer 2 is more excellent in the anti-foaming property and the step followability under high temperature and high humidity conditions.

As described above, as the second selective condition, the 100% modulus of the adhesive constituting the first adhesive layer 21 and the 100% modulus of the adhesive constituting the second adhesive layer 22 are respectively 60 kPa or more, preferably 70 kPa or more, particularly preferably Above 80kPa. Further, the 100% modulus is preferably 150 kPa or less, particularly preferably 140 kPa or less, and further preferably 130 kPa or less. The 100% modulus is 150 kPa or less, whereby the step followability of the adhesive layer 2 can be kept high. In addition, the 100% modulus of the adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 The 100% modulus of the adhesive can be the same or different.

Furthermore, as the second selectivity condition, compared with the 100% modulus of the adhesive constituting the first adhesive layer 21 and the 100% modulus of the adhesive constituting the second adhesive layer 22, the third adhesive The 100% modulus before curing of the active energy ray-curable adhesive of the layer 23 is set to be lower. As a specific value, the storage elastic modulus (G') is preferably 60 kPa or less, particularly preferably 50 kPa or less, and further preferably 40 kPa or less. Thereby, the adhesive bond layer 2 can be made the one which is more excellent in the step followability. Further, the 100% modulus is preferably 5 kPa or more, particularly preferably 10 kPa or more, and further preferably 15 kPa or more. Thereby, the adhesive bond layer 2 can be made into one whose workability is more favorable. In addition, the measuring method of the said 100% modulus is shown in the test example mentioned later.

Here, the 100% modulus of the active energy ray-curable adhesive constituting the third adhesive layer 23 after curing (after curing by active energy ray irradiation) is preferably 30 kPa or more, more preferably 40 kPa or more, and 50 kPa The above is further preferred. Thereby, the adhesive bond layer 2 can be made the one which is more excellent in the anti-foaming property and the step followability under high temperature and high humidity conditions. On the other hand, the 100% modulus is preferably 300 kPa or less, particularly preferably 200 kPa or less, and further preferably 180 kPa or less. Thereby, the adhesive force of the 3rd adhesive bond layer 23, especially the adhesive force with respect to the 1st adhesive bond layer 21 and the 2nd adhesive bond layer 22 can be kept high.

In addition, compared with the 100% modulus of the adhesive constituting the first adhesive layer 21 and the 100% modulus of the adhesive constituting the second adhesive layer 22, the active energy ray curability of the third adhesive layer 23 The 100% modulus of the adhesive after hardening (after hardening based on active energy ray irradiation) can be smaller, or To be larger, the two can also be the same. Among these, the active energy rays constituting the third adhesive layer 23 are compared with the 100% modulus of the adhesive constituting the first adhesive layer 21 and the 100% modulus of the adhesive constituting the second adhesive layer 22 . The 100% modulus after hardening of the hardening adhesive is preferably larger. As a result, the adhesive layer 2 is more excellent in the anti-foaming property and the step followability under high temperature and high humidity conditions.

The ratio of the total thickness of the first adhesive layer 21 and the second adhesive layer 22 to the thickness of the third adhesive layer 23 is preferably 0.3 or more, particularly preferably 0.4 or more, and further preferably 0.5 or more. In addition, the ratio is preferably 5 or less, particularly preferably 3 or less, more preferably 2 or less, and most preferably 0.8 or less. When the ratio falls within the above-mentioned range, the above-mentioned effects of step followability, foam resistance, and processability can be more favorably exhibited. In addition, let the thickness of each layer be the value measured based on JISK7130.

The total thickness of the adhesive layer 2 is preferably 50 μm or more, particularly preferably 75 μm or more, and further preferably 100 μm or more. Moreover, the total thickness is preferably 300 μm or less, particularly preferably 250 μm or less, and even more preferably 200 μm or less. When the total thickness of the adhesive layer 2 falls within the above-mentioned range, the aforementioned effects of step followability, foam resistance, and processability can be more favorably exhibited.

The thickness of the first adhesive layer 21 and the thickness of the second adhesive layer 22 are preferably 25 μm or more, particularly preferably 30 μm or more, and further preferably 50 μm or more. Moreover, the thickness is preferably 100 μm or less, particularly preferably 80 μm or less, and further preferably 75 μm or less. When the thickness is within the above-mentioned range, the above-mentioned effects of step followability, blister resistance, and workability can be more favorably exhibited. In addition, the thickness of the first adhesive layer 21 and the thickness of the second adhesive layer 22 may be the same or different.

The thickness of the third adhesive layer 23 is preferably 25 μm or more, particularly preferably 30 μm or more, and even more preferably 50 μm or more. The thickness is preferably 150 μm or less, particularly preferably 125 μm or less, further preferably 100 μm or less, and most preferably 75 μm or less. When the thickness falls within the above-mentioned range, the aforementioned effects of step followability, blister resistance, and workability can be more favorably exhibited.

1. The first adhesive layer and the second adhesive layer

The adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are not particularly limited as long as they satisfy the aforementioned physical properties, and may be an active energy ray curable adhesive or an active energy ray non-sensitive adhesive. Curable adhesives, but active energy ray non-curable adhesives are preferred. Thereby, the adhesiveness (adhesive force) with respect to the to-be-adhered body (especially a display body constituent member) after the active energy ray is irradiated to the adhesive layer 2 can be kept high. Moreover, the adhesive which comprises a 1st adhesive layer and the adhesive which comprises a 2nd adhesive layer may be mutually the same adhesive, and may be a different adhesive.

Hereinafter, the active energy ray non-curable adhesive will be mainly described. In addition, in the case of an active energy ray-curable adhesive, the same adhesive as the active energy ray-curable adhesive that constitutes the third adhesive layer 23 described later can be used.

Examples of active energy ray non-curable adhesives constituting the first adhesive layer and the second adhesive layer include acrylic adhesives, rubber-based adhesives, silicone-based adhesives, urethane-based adhesives, polyester Any of adhesives, polyvinyl ether-based adhesives, etc. Moreover, the adhesive may be any of an emulsion type, a solvent type, or a solvent-free type, and may be any of a cross-linked type or a non-cross-linked type.

Among the above, acrylic adhesives are preferred. In this case, the adhesive in the present embodiment is obtained from the adhesive composition (hereinafter, sometimes referred to as "adhesive composition P") containing the (meth)acrylate polymer (A). better. It is preferable that the adhesive composition P further contains a crosslinking agent (B). In this case, the adhesive in this embodiment can be obtained by crosslinking the adhesive composition P. In addition, in this specification, (meth)acrylate means both an acrylate and a methacrylate. The same applies to other similar terms. In addition, "polymer" also includes the concept of "copolymer".

(1) (Meth)acrylate polymer (A)

(Meth)acrylate polymer (A) can exhibit better adhesion by using alkyl (meth)acrylate having an alkyl group of 1 to 20 carbon atoms as a monomer unit constituting the polymer . From such a viewpoint, the (meth)acrylate polymer (A) contains an alkyl group (meth)acrylate having a lower limit of 50 mass % or more and an alkyl group having 1 to 20 carbon atoms as a constituent of the polymerization The monomer unit of the material is preferably contained, particularly preferably 60% by mass or more, and even more preferably 70% by mass or more. When 50 mass % or more of said alkyl (meth)acrylates are contained, the (meth)acrylate polymer (A) can exhibit favorable adhesiveness. In addition, the (meth)acrylate polymer (A) preferably contains the above-mentioned alkyl (meth)acrylate having an upper limit of 97% by mass or less as a monomer unit constituting the polymer, preferably 90% by mass The following is particularly preferred, and the content of 85% by mass or less is further preferred. By containing 97 mass % or less of the said alkyl (meth)acrylate, the other monomer component of a preferable amount can be introduce|transduced into (meth)acrylate polymer (A).

(Meth)acrylic acid alkyl group having 1 to 20 carbon atoms as an alkyl group Esters, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, (meth)acrylate base) n-hexyl acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, (meth)acrylate base) tetradecyl acrylate, cetyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, ( Among them, adamantyl meth)acrylate and the like, from the viewpoint of further improving the adhesiveness, a (meth)acrylate containing an alkyl group and having a carbon number of 4 to 8 is preferable. These may be used alone or in combination of two or more. In addition, the alkyl group in the alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group means a linear, branched or cyclic alkyl group.

In addition, as the alkyl (meth)acrylate having 1 to 20 carbon atoms as the alkyl group, a hard monomer whose glass transition temperature (Tg) exceeds 0°C (preferably 70°C or higher) as a homopolymer is used in combination Soft monomers having a glass transition temperature (Tg) of 0°C or lower as a bulk and a homopolymer are also preferred. This is because the adhesiveness and flexibility are maintained by the soft monomer, and the cohesive force is improved by the hard monomer, thereby making it possible to make it more excellent in step followability. At this time, the mass ratio of the hard monomer to the soft monomer is preferably 5:95 to 40:60, and particularly preferably 20:80 to 30:70.

Examples of the hard monomers include methyl acrylate (Tg10°C), methyl methacrylate (Tg105°C), isobornyl acrylate (Tg94°C), isobornyl methacrylate (Tg180°C), diamond acrylate Alkyl ester (Tg115°C), adamantyl methacrylate (Tg141°C), etc. These may be used alone or in combination of two or more.

Among the above-mentioned hard monomers, from the prevention of adhesion and transparency, etc. Methyl acrylate, methyl methacrylate, and isobornyl acrylate are preferred from the viewpoint of adversely affecting other properties and further exerting the performance of the hard monomer. If tackiness is also considered, methyl acrylate and methyl methacrylate are more preferable, and methyl methacrylate is especially preferable.

As said soft monomer, the alkyl acrylate which has a C2-C12 linear or branched alkyl group is mentioned preferably. For example, 2-ethylhexyl acrylate (Tg-70 degreeC), n-butyl acrylate (Tg-54 degreeC) etc. are mentioned preferably. These may be used alone or in combination of two or more.

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

As the reactive functional group-containing monomer contained in the (meth)acrylate polymer (A) as a monomer unit constituting the polymer, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer) is preferably used. monomers), monomers with carboxyl groups in the molecule (carboxyl group-containing monomers), monomers with amine groups in the molecules (amine group-containing monomers), and the like. Among these, hydroxyl-containing monomers which are excellent in reactivity with the crosslinking agent (B) and have little influence on the object to be adhered are particularly preferable.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxypropyl (meth)acrylate. Hydroxyalkyl (meth)acrylates such as hydroxybutyl, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like. Among them, from the obtained (meth)acrylate polymer (A), From the viewpoint of the reactivity of the hydroxyl group with the crosslinking agent (B) and the copolymerizability with other monomers, 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferable. 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 viewpoint of reactivity with the crosslinking agent (B) and the reactivity of the carboxyl group in the obtained (meth)acrylate polymer (A) 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.

When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, the lower limit of the content is preferably 3% by mass or more, and preferably 10% by mass or more. Particularly preferred, 15% by mass or more is further preferred. Moreover, the upper limit of the content is preferably 35 mass % or less, particularly preferably 30 mass % or less, and further preferably 25 mass % or less. When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit in the above amount, a predetermined amount of hydroxyl groups will remain in the obtained adhesive. Hydroxyl is a hydrophilic group. If there is a predetermined amount of this hydrophilic group in the adhesive, even if the adhesive is placed under high temperature and high humidity conditions, it will not be immersed in the adhesive under the high temperature and high humidity conditions. The compatibility with water was also good, and as a result, whitening of the adhesive was suppressed when returning to a normal temperature and normal humidity state (excellent in moist heat whitening resistance).

(Meth)acrylate polymer (A) contains a carboxyl group-containing monomer to In the case of a monomer unit constituting the polymer, the lower limit of the content is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 6% by mass or more. Moreover, the upper limit of the content is preferably 20 mass % or less, more preferably 15 mass % or less, and particularly preferably 10 mass % or less.

In addition, when the adherend is a material that is easily adversely affected by acid, such as a transparent conductive film or metal wiring, etc., in the (meth)acrylate polymer (A), as the monomer unit constituting the polymer It is preferable that it does not contain a carboxyl group-containing monomer. Thereby, for example, corrosion of the transparent conductive film or metal wiring can be suppressed, or the resistance value of the transparent conductive film can be changed.

Here, "does not contain a carboxyl group-containing monomer" means substantially does not contain a carboxyl group-containing monomer, and in addition to completely not containing a carboxyl group-containing monomer, it is allowed to contain a carboxyl group-containing monomer on the basis of: Corrosion of the transparent conductive film or metal wiring due to the carboxyl group occurs. Specifically, the (meth)acrylate polymer (A) is allowed to contain 0.01 mass % or less of the carboxyl group-containing monomer as a monomer unit, preferably 0.001 mass % or less.

The (meth)acrylate polymer (A) may contain other monomers as monomeric units constituting the polymer as needed. As other monomers, in order not to hinder the action of the reactive functional group-containing monomer, it is preferable to use a monomer that does not contain a reactive functional group. Examples of such other monomers include alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, and (meth)acrylic acid N,N-dimethylaminoethyl ester, (meth)acrylic acid N,N-dimethylaminopropyl ester, (meth)acryloyl morpholine and other non-crosslinkable tertiary amine groups (Meth)acrylate, (meth)acrylamide, dimethylacrylamide, vinyl acetate, styrene, and the like. such can It can be used alone or in combination of two or more.

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

The lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 200,000 or more, particularly preferably 300,000 or more, and further preferably 400,000 or more. In addition, the weight average molecular weight in this specification is the standard polystyrene conversion value measured by gel permeation chromatography (GPC). If the lower limit of the weight average molecular weight of the (meth)acrylate polymer (A) is equal to or more than the above lower limit, the adhesive will be more excellent in anti-foaming properties and step followability under high temperature and high humidity conditions.

In addition, the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is preferably 1 million or less, particularly preferably 900,000 or less, and even more preferably 700,000 or less. If the upper limit of the weight average molecular weight of the (meth)acrylate polymer (A) is the above-mentioned or less, the adhesive will be more excellent in step followability at the time of sticking.

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

(2) Cross-linking agent (B)

The adhesive composition P preferably contains a crosslinking agent (B). The adhesive composition P contains a cross-linking agent (B) to cross-link the (meth)acrylate polymer (A) to form a three-dimensional network structure, which can improve the cohesion of the obtained adhesive, thereby further improving the resistance. Foaming and step followability under high temperature and high humidity conditions.

The crosslinking agent (B) may be one that reacts with the reactive group having the (meth)acrylate polymer (A), for example, an isocyanate-based crosslinking agent. , epoxy-based cross-linking agent, amine-based cross-linking agent, melamine-based cross-linking agent, aziridine-based cross-linking agent, amine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal Alkoxide-based cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, ammonium salt-based cross-linking agents, etc. When the (meth)acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an isocyanate-based crosslinking agent having excellent reactivity with the hydroxyl group. Moreover, when the (meth)acrylate polymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer, it is preferable to use an epoxy-based crosslinking agent having excellent reactivity with the carboxyl group . In addition, the crosslinking agent (B) may be used alone or in combination of two or more.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. 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 preferable, and trimethylolpropane-modified toluene diisocyanate is particularly preferable.

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 ether Hydroglyceramine, 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 0.001 parts by mass or more, particularly 0.01 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). Preferably, 0.02 mass part or more is further preferable. In addition, the upper limit is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and even more preferably 1 part by mass or less.

When the content of the crosslinking agent (B) is within the above range, the cohesive force of the obtained adhesive becomes better, and the anti-foaming property of the adhesive and the step followability under high temperature and high humidity conditions are improved.

(3) Various additives

Various additives commonly used in acrylic adhesives, such as silane coupling agents, antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, can be added to the adhesive composition P as required. agent, refractive index modifier, etc.

In addition, the adhesive composition P refers to a mixture of various components remaining in the adhesive layer in the original state or in a reacted state, and components removed in the drying process, such as the polymerization solvent and diluting solvent described later, are not included in the adhesive In sexual composition P.

Here, when the adhesive composition P contains a silane coupling agent, the adhesiveness of the obtained adhesive agent to a glass member or a plastic plate is improved. Thereby, the obtained adhesive becomes more excellent in the anti-foaming property and the step followability under high temperature and high humidity conditions.

As a silane coupling agent, it has at least one alkoxy Silicon-based organosilicon compounds with good compatibility with the (meth)acrylate polymer (A) and light transmittance are preferred.

Examples of such silane coupling agents include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloyloxypropyltrimethoxysilane. 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and other silicon compounds with epoxy structure, 3-mercaptopropyltrimethoxysilane Silane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane and other mercapto-containing silicon compounds, 3-aminopropyltrimethoxysilane, N-(2-amino Ethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane and other amino-containing silicon compounds, 3-chloro propyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these combined with methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyl Condensates of alkyl-containing silicon compounds such as trimethoxysilane, etc. These may be used individually by 1 type, and may be used in combination of 2 or more types.

When the adhesive composition P contains a silane coupling agent, the lower limit of the content is preferably 0.01 parts by mass or more, particularly preferably 0.05 parts by mass or more, relative to 100 parts by mass of the (meth)acrylate polymer (A). 0.1 mass part or more is more preferable. Furthermore, the upper limit of the content is preferably 5 parts by mass or less, particularly preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less.

(4) Manufacture of adhesive composition

The adhesive composition P can be produced by producing a (meth)acrylate polymer (A) and, if necessary, adding a crosslinking agent (B) to the obtained (meth)acrylate polymer (A) and additives.

The (meth)acrylate polymer (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 polymer (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. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane Alkane 1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxypentane) nitrile), 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.

When the (meth)acrylate polymer (A) is obtained, the crosslinking agent (B) is added to the solution of the (meth)acrylate polymer (A) as required. ), additives and diluting solvent and mix well, thereby obtaining the adhesive composition P (coating solution) diluted with solvent. 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 becomes a coating solution using the polymerization solvent of the (meth)acrylate polymer (A) as a dilution solvent as it is.

(5) Manufacture of adhesive

The adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 can be preferably obtained by crosslinking the adhesive composition P. The crosslinking of the adhesive composition P can usually be performed by heat treatment. In addition, the drying treatment which is performed when the diluting solvent or the like is volatilized from the coating film of the adhesive composition P applied to the desired object can also be used as the heating treatment.

The heating temperature of the heating treatment is preferably 50~150°C, and 70~150°C is preferable. 120°C is particularly preferred. 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 aging), (when a crosslinking agent (B) is contained, the (meth)acrylate polymer (A) is sufficiently crosslinked via the crosslinking agent (B)).

(6) Gel fraction

The lower limit of the gel fraction of the adhesive constituting the first adhesive layer 21 and the adhesive constituting the second adhesive layer 22 is preferably 50% or more, particularly preferably 60% or more, and furthermore better. When the gel fraction of the adhesive is 50% or more, the cohesive force of the adhesive becomes high, and the adhesive layer 2 has better anti-foaming properties and step followability under high temperature and high humidity. Further, the upper limit of the gel fraction of the adhesive is preferably 85% or less, particularly preferably 80% or less, and further preferably 75% or less. If the gel fraction of the adhesive is 85% or less, the adhesive will not become too hard, and the adhesive layer will be more excellent in step followability. Here, the measurement method of the gel fraction of an adhesive is shown in the test example mentioned later.

(7) Adhesion

The lower limit of the adhesive force of the first adhesive layer 21 (the laminate with the base material) and the second adhesive layer 22 (the laminate with the base material) relative to the soda lime glass is preferably 5N/25mm or more. , 10N/25mm or more is particularly preferred, and 15N/25mm or more is further preferred. When the adhesive force is equal to or more than the above lower limit value, the anti-foaming property will be And the step followability under high temperature and high humidity conditions is more excellent. Further, the upper limit of the adhesive force is preferably 50N/25mm or less, particularly preferably 40N/25mm or less, and further preferably 35N/25mm or less. When this adhesive force is below the said upper limit, favorable reworkability can be obtained, and when a bonding error occurs, the expensive display body constituent member can be reused.

Here, the adhesive force in this specification basically means the adhesive force measured by the 180-degree peeling method in accordance with JIS Z0237:2009, and the adhesive force is a measurement sample with a width of 25 mm and a length of 100 mm. The sample was attached to the adherend, pressurized at 0.5 MPa and 50°C for 20 minutes, then left to stand for 24 hours under the conditions of normal pressure, 23°C, and 50% RH, and then measured at a peeling speed of 300 mm/min. Moreover, as the said base material, the polyethylene terephthalate film of thickness 100 micrometers was used.

(8) Follow rate of step difference

For the first adhesive layer 21 and the second adhesive layer 22 , the lower limit of the step follow-up ratio (%) represented by the following formula is preferably 10% or more, particularly preferably 15% or more, and further more preferably 20% or more. better. Further, the upper limit of the step following rate (%) is preferably 50% or less, particularly preferably 45% or less, and further preferably 40% or less.

Step follow-up rate (%) = {(Height (μm) of the step after the specified durability test, no air bubbles, floating, peeling, etc., and the filling state is maintained)/(The 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 step following ratios of the first adhesive layer 21 and the second adhesive layer 22 as the outer layers are within the above-mentioned range, whereby the adhesive sheet 1 of the present embodiment is used. The adhesive layer 2 is easy to become the one with more excellent step followability.

2. The third adhesive layer

The active energy ray-curable adhesive constituting the third adhesive layer 23 is not particularly limited as long as it satisfies the aforementioned physical properties. The active energy ray-curable adhesive preferably contains at least any one of active energy ray-curable monomers, oligomers and polymers, or a mixture thereof, and may also contain active energy ray-curable monomers. Any one of a body, an oligomer and a polymer, or a mixture thereof.

In the present embodiment, it is preferable that the active energy ray-curable adhesive constituting the third adhesive layer 23 can be obtained from the adhesive composition Q containing a (meth)acrylate polymer (C) and the active energy ray curable compound (D). It is preferable that the adhesive composition Q further contains a crosslinking agent (B). In this case, the above-mentioned active energy ray-curable adhesive can be obtained by crosslinking the adhesive composition Q.

(1) (Meth)acrylate polymer (C)

The (meth)acrylate polymer (C) is basically the same as the aforementioned (meth)acrylate polymer within the range where the active energy ray-curable adhesive constituting the third adhesive layer 23 satisfies the aforementioned physical properties. (A) the same. However, the third adhesive layer 23 is an intermediate layer and will not be in direct contact with the adherend. Therefore, the (meth)acrylate polymer (C) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer. is better.

In addition, it is also preferable that the (meth)acrylate polymer (C) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer. The presence of a nitrogen atom-containing monomer as a constituent unit in the polymer promotes (meth)acrylate Crosslinking reaction of the reactive functional groups of the polymer (C) with the crosslinking agent (B). Examples of the above-mentioned nitrogen atom-containing monomers include monomers having an amine group, monomers having an amide group, monomers having a nitrogen-containing heterocyclic ring, and the like. Among them, the (meth)acrylate polymer (C ) from the viewpoint of having an appropriate rigidity, a monomer having a nitrogen-containing heterocycle 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-vinylcarbazole, N-vinylphthalimide, etc. Among them, N-(methyl) which exerts more excellent adhesion yl) acryl morpholine is preferred, and N-acryl morpholine is particularly preferred.

In addition, as the nitrogen atom-containing monomer, for example, (meth)acrylamide, N-methyl(meth)acrylamide, N-methylol(meth)acrylamide, N-tert-butyl can also be used N,N-dimethyl(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-ethylene Caprolactam, Monomethylaminoethyl (meth)acrylate, Monoethylaminoethyl (meth)acrylate, Monomethylaminopropyl (meth)acrylate, (meth)acrylic acid Monoethylaminopropyl ester, dimethylaminoethyl (meth)acrylate, etc.

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

When the (meth)acrylate polymer (C) contains a nitrogen atom-containing monomer as a monomer unit constituting the polymer, the nitrogen atom-containing monomer is preferably contained in an amount of 1 mass % or more, and 2 mass % is contained % or more is particularly preferred, and 3 mass % or more is further more preferred. In addition, the (meth)acrylate polymer (A) preferably contains 20% by mass or less of the nitrogen atom-containing monomer as a monomer unit constituting the polymer, particularly preferably 15% by mass or less, and contains 10% by mass or less. Mass % or less is more preferable. If the content of the nitrogen atom-containing monomer is within the above range, the effect of promoting the crosslinking reaction between the (meth)acrylate polymer (C) and the crosslinking agent (B) can be favorably obtained.

(2) Active energy ray curable compound (D)

When the adhesive composition Q contains the active energy ray-curable compound (D), when the active energy ray-curable adhesive agent is cured by irradiation with active energy rays, the active energy ray-curable compounds (D) are polymerized with each other, and the active energy ray-curable compounds (D) are polymerized together. The energy ray-curable adhesive is formed by thermally crosslinking the adhesive composition Q, so it is presumed that the polymerized active energy ray-curable compound (D) is entangled into a (meth)acrylate polymer (A) ) of the cross-linked structure (three-dimensional network structure). The adhesive having the above-mentioned higher-order structure has high cohesion and shows a relatively high elastic modulus, so the adhesive layer 2 having the third adhesive layer 23 as an intermediate layer is more excellent in anti-foaming properties.

The active energy ray-curable compound (D) is cured by irradiation with active energy rays, and is not particularly limited as long as it is a compound that can obtain the above-mentioned effects, and may be any of a monomer, an oligomer, or a polymer. One can also be a mixture of them. Among these, polyfunctional propylene having excellent compatibility with the (meth)acrylate polymer (C) and the like and having a molecular weight of less than 1000 is preferably used. alkenoate monomers.

Examples of polyfunctional acrylate-based monomers having a molecular weight of less than 1,000 include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl di(meth)acrylate. Alcohol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate Acrylate, dicyclopentyl di(meth)acrylate, caprolactone modified dicyclopentyl di(meth)acrylate, ethylene oxide modified phosphoric acid di(meth)acrylate, di(propylene) Ethoxyethyl) isocyanurate, allyl cyclohexyl di(meth)acrylate, ethoxylated bisphenol A diacrylate, 9,9-bis[4-(2-propenyl) 2-functional type such as oxyethoxy) phenyl] stilbene; trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylic acid Ester, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, tris(acrylooxyethyl) isocyanurate, ε-caprolactone modified 3-functional type such as tri-(2-(meth)acrylooxyethyl)isocyanurate; 4-functional type such as diglycerol tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; Propionic acid-modified dipentaerythritol penta(meth)acrylate and other 5-functional types; dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate and other 6-functional types, etc. Among the above, from the viewpoint of the anti-foaming property of the obtained adhesive layer, pentaerythritol tri(meth)acrylate, ε-caprolactone-modified tris-(2-(meth)acryloyloxy) Ethyl) isocyanurate is preferred. These may be used individually by 1 type, and may be used in combination of 2 or more types.

As the active energy ray curable compound (D), it is also possible to use An acrylate-based oligomer curable with active energy rays. The acrylate-based oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, Silicone acrylate, etc.

The upper limit of the weight average molecular weight of the acrylate-based oligomer is preferably 50,000 or less, and particularly preferably 40,000 or less. Moreover, it is preferable that the lower limit of this weight average molecular weight is 500 or more, and it is especially preferable that it is 3,000 or more. These acrylate-based oligomers may be used alone or in combination of two or more.

Moreover, as an active energy ray curable compound (D), the addition acrylate type polymer which introduced the group which has a (meth)acryloyl group in a side chain can also be used. Such an addition acrylate-based polymer can be obtained by using a copolymer of (meth)acrylate and a monomer having a crosslinkable functional group in the molecule, and a part of the crosslinkable functional group of the copolymer, It is obtained by reacting with a compound having a group capable of reacting with a (meth)acryloyl group and a crosslinkable functional group.

The lower limit of the weight average molecular weight of the addition acrylate polymer is preferably 50,000 or more, and particularly preferably 100,000 or more. In addition, the upper limit of the weight average molecular weight is preferably 900,000 or less, and particularly preferably 500,000 or less.

The active energy ray-curable compound (D) may be selected from the aforementioned polyfunctional acrylate-based monomers, acrylate-based oligomers, and addition acrylate-based polymers, or may be used in combination of two or more, or may be used in combination. It is used in combination with active energy ray curable components other than these.

Regarding the content of the active energy ray-curable compound (D) in the adhesive composition Q, from the viewpoint of improving the cohesive force of the obtained adhesive and making the anti-foaming property excellent, compared with (meth)acrylate polymerization 100 parts by mass of the substance (C), the lower limit is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and particularly preferably 3.0 parts by mass or more. On the other hand, the upper limit of the content is preferably 50 parts by mass or less from the viewpoint of preventing phase separation of the active energy ray-curable compound (D) and the (meth)acrylate polymer (C), 20 mass parts or less is more preferable, and 12 mass parts or less is especially preferable from the viewpoint of making the anti-foaming property more excellent.

(3) Cross-linking agent (B)

The adhesive composition Q preferably contains a crosslinking agent (B). The adhesive composition Q contains a cross-linking agent (B), whereby the (meth)acrylate polymer (C) can be cross-linked to form a three-dimensional network structure, thereby improving the cohesion of the obtained adhesive and further improving Anti-foaming and step followability under high temperature and high humidity conditions. As the crosslinking agent (B), the same crosslinking agent as the one described in the adhesive composition P can be used, and the usage amount is also the same.

(4) Photopolymerization initiator (E)

When the active energy ray-curable adhesive constituting the third adhesive layer 23 is cured, when ultraviolet rays are used as the active energy ray to be irradiated, the adhesive composition Q further contains a photopolymerization initiator (E). good. By containing the photopolymerization initiator (E) in this way, the active energy ray-curable compound (D) can be efficiently polymerized, and the polymerization curing time and the irradiation amount of the active energy ray can be reduced.

As such a photopolymerization initiator (E), for example, Anxi can be mentioned. Incense, benzoin methyl ether, benzoin ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenyl Acetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 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'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethyl Anthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone Xanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo[2-hydroxy-2 -Methyl-1[4-(1-methylvinyl)phenyl]acetone], 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide, etc. These may be used alone or in combination of two or more.

Regarding the content of the photopolymerization initiator (E) in the adhesive composition Q, the lower limit is preferably 0.1 part by mass or more, preferably 1 part by mass or more, relative to 100 parts by mass of the active energy ray-curable compound (D). Excellent. In addition, the upper limit is preferably 30 parts by mass or less, and particularly preferably 10 parts by mass or less.

(5) Various additives

In the adhesive composition Q, various additives commonly used in acrylic adhesives, such as silane coupling agents, antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, can be added as required. agent, refractive index modifier, etc.

In addition, the adhesive composition Q represents a mixture of various components that remain in the adhesive layer directly or in a state of being reacted, and the adhesive composition The finished product Q does not contain components removed in the drying process or the like, for example, a polymerization solvent or a dilution solvent to be described later.

(6) Manufacture of adhesive composition

The adhesive composition Q can be produced by producing a (meth)acrylate polymer (C), and treating the obtained (meth)acrylate polymer (C) and the active energy ray curable compound (D) ), while mixing, if necessary, a crosslinking agent (B), a photopolymerization initiator (E), and additives are added. Specifically, it can be manufactured by the same method as the manufacturing method of the adhesive composition P.

(7) Manufacture of adhesive

The active energy ray-curable adhesive constituting the third adhesive layer 23 can be preferably obtained by crosslinking (thermally crosslinking) the adhesive composition Q. The crosslinking of the adhesive composition Q can be performed by the same method as the crosslinking method of the adhesive composition P.

(8) Gel fraction

The lower limit of the gel fraction before curing of the active energy ray-curable adhesive constituting the third adhesive layer 23 is preferably 40% or more, particularly preferably 45% or more, and further preferably 50% or more. When the gel fraction before hardening is 40% or more, the cohesive force of the active energy ray-curable adhesive becomes high, and the adhesive layer 2 becomes one with better workability. In addition, the upper limit of the gel fraction before hardening is preferably 75% or less, particularly preferably 70% or less, and further preferably 65% or less. If the gel fraction before curing is 75% or less, the active energy ray-curable adhesive will not become too hard, and the adhesive layer 2 will be more excellent in the initial step followability.

Active energy ray-curable adhesive constituting the third adhesive layer 23 The lower limit of the gel fraction after curing of the agent (after curing by active energy ray irradiation) is preferably 70% or more, particularly preferably 75% or more, and further preferably 79% or more. When the gel fraction after curing is 70% or more, the cohesive force becomes high, and the adhesive layer becomes more excellent in the anti-foaming property and the step followability under high temperature and high humidity. In addition, the upper limit of the gel fraction after curing is preferably 95% or less, particularly preferably 92% or less, and further preferably 90% or less. When the gel fraction after curing is 95% or less, the adhesiveness with the adjacent first adhesive layer 21 and the second adhesive layer 22 is excellent, whereby the adhesive layer has anti-foaming properties and high temperature. The one with better step followability under high humidity. Here, the measurement method of the gel fraction of an active energy ray-curable adhesive is shown in the test example mentioned later.

(9) Adhesion

The lower limit of the adhesive force relative to the soda lime glass before hardening of the active energy ray-curable adhesive (the laminate with the base material) constituting the third adhesive layer 23 is preferably 20N/25mm or more, preferably 25N/25mm The above is particularly preferred, and 30N/25mm or more is further preferred. Adhesion with the 1st adhesive bond layer 21 and the 2nd adhesive bond layer 22 becomes high that the adhesive force before this hardening is more than the said lower limit, and the interlayer peeling in the adhesive bond layer 2 can be suppressed. In addition, the upper limit value of the said adhesive force is not specifically limited, Usually, 50N/25mm or less is preferable, and 45N/25mm or less is especially preferable.

The lower limit of the adhesive force with respect to soda lime glass after curing (after curing by active energy ray irradiation) of the active energy ray-curable adhesive (the laminate with the base material) constituting the third adhesive layer 23 is 20N /25mm or more is preferable, 25N/25mm or more is particularly preferable, and 30N/25mm or more is further preferable. When the adhesive force after the hardening is equal to or more than the above lower limit value, it will be The adhesiveness of 21 and the 2nd adhesive bond layer 22 becomes high, and the obtained product (display body) becomes the one with high durability. In addition, the upper limit value of the said adhesive force is not specifically limited, Usually, 55N/25mm or less is preferable, and 50N/25mm or less is especially preferable.

(10) Follow rate of step difference

The lower limit of the step following rate (%) after curing of the third adhesive layer 23 (after curing by active energy ray irradiation) is preferably 30% or more, particularly preferably 35% or more, and further more preferably 40% or more. good. In addition, the upper limit of the step following rate (%) is preferably 65% or less, particularly preferably 60% or less, and further preferably 55% or less.

The step follow-up rate of the third adhesive layer 23 serving as the intermediate layer is within the above-mentioned range, whereby the adhesive layer 2 of the adhesive sheet 1 of the present embodiment is more excellent in step followability.

3. Peel off sheet

The release sheets 31 and 32 protect the adhesive layer 2 before using the adhesive sheet 1, and are peeled off when the adhesive sheet 1 (the adhesive layer 2) is used. In the pressure-sensitive adhesive sheet 1 of the present embodiment, one or both of the release sheets 31 and 32 are not necessarily required.

As the release sheets 31 and 32, 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 film, vinyl acetate film, ionomer resin film, vinyl. (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 peeling treatment is performed on the peeling surfaces of the peeling sheets 31 and 32 (particularly, the surfaces in contact with the adhesive layer 2). 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. Moreover, among the peeling sheets 31 and 32, it is preferable that one peeling sheet is a heavy peeling type peeling sheet with a large peeling force, and the other peeling sheet is a light peeling type peeling sheet with a small peeling force.

The thickness of the release sheets 31 and 32 is not particularly limited, but is usually about 20 to 150 μm.

4. Physical properties of adhesive sheet

(1) Follow rate of step difference

The lower limit of the step tracking rate (%) after the adhesive layer 2 of the adhesive sheet 1 of the present embodiment is cured (after curing by active energy ray irradiation) is preferably 25% or more, and particularly preferably 30% or more. 40% or more is further preferable. Further, the upper limit of the step following rate (%) is preferably 60% or less, particularly preferably 55% or less, and further preferably 50% or less.

As described above, since the adhesive layer 2 in the present embodiment is excellent in step followability, it is possible to realize a high step follow rate as described above. Thereby, the adhesive layer 2 satisfactorily follows the step difference of the constituent members of the display body, and can suppress generation of air bubbles, floating, peeling, etc. in the vicinity of the step difference even after the durability test, thereby suppressing the occurrence of reflection loss of light.

(2) 100% modulus

Before hardening of the adhesive layer 2 of the adhesive sheet 1 of the present embodiment (based on activity The lower limit value of the 100% modulus (before curing by energy ray irradiation) is preferably 40 kPa or more, particularly preferably 50 kPa or more, and further preferably 60 kPa or more. When the lower limit value of the above-mentioned 100% modulus is equal to or more than the above-mentioned lower limit value, the adhesive layer 2 has better workability. In addition, the upper limit of the 100% modulus before hardening of the adhesive layer 2 is preferably 200 kPa or less, particularly preferably 150 kPa or less, and further preferably 90 kPa or less. The upper limit value of the above-mentioned 100% modulus is equal to or less than the above-mentioned upper limit value, whereby the adhesive layer 2 is more excellent in initial step followability.

The lower limit of the 100% modulus of the adhesive layer 2 of the adhesive sheet 1 of the present embodiment after curing (after curing by active energy ray irradiation) is preferably 70 kPa or more, particularly preferably 80 kPa or more, and further more preferably 125 kPa or more. better. The lower limit of the above-mentioned 100% modulus is equal to or more than the above-mentioned lower limit, whereby the adhesive layer 2 is more excellent in anti-foaming property and step followability under high temperature and high humidity. In addition, the upper limit of the 100% modulus before hardening of the adhesive layer 2 is preferably 200 kPa or less, particularly preferably 170 kPa or less, and further preferably 150 kPa or less. The upper limit of the 100% modulus is below the upper limit, whereby the adhesiveness (adhesive force) of the adhesive layer 2 with respect to the adherend (display member) can be easily maintained high.

5. 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 31, and the adhesive composition P is thermally cross-linked by heat treatment to form a coating layer, whereby the release sheet 31 with the coating layer of the adhesive composition P is obtained. Moreover, the coating liquid of the above-mentioned adhesive composition P is applied to the release surface of the other release sheet 32, and the adhesive composition P is thermally cross-linked by heat treatment to form a coating layer, thereby obtaining the adhesive composition P. stickiness The release sheet 32 of the coating layer of the composition P. Then, the coating liquid of the above-mentioned adhesive composition Q is applied to the release surface of the other release sheet, and the adhesive composition Q is thermally cross-linked by heat treatment to form a coating layer, thereby obtaining an additional adhesive A release sheet for the coating layer of the composition Q.

After that, the release sheet 31 of the coating layer with the adhesive composition P and the release sheet with the coating layer of the adhesive composition Q are laminated in such a way that the two coating layers are in contact with each other, and from the adhesive composition The coating layer of substance Q peeled off the release sheet. Next, the coating layer of the adhesive composition Q and the release sheet 32 with the coating layer of the adhesive composition P are bonded together so that the two coating layers are in contact with each other. When the curing period is required, and the curing period is not required after the curing period, the coating layer of one of the above-mentioned layers of the adhesive composition P can be directly used as the first adhesive layer 21, which is composed of the adhesive composition Q. The coating layer made of the other adhesive composition P becomes the third adhesive layer 23 , and the coating layer made of another adhesive composition P becomes the second adhesive layer 22 . Thereby, the adhesive sheet 1 can be obtained in which the adhesive composed of the first adhesive layer 21 , the third adhesive layer 23 and the second adhesive layer 22 is sandwiched by the release sheet 31 and the release sheet 32 . layer 2. In addition, the aging of the coating layer of the adhesive composition may be performed after bonding the coating layers of the adhesive composition to three layers as described above, or may be performed before bonding.

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. .

Since the adhesive sheet 1 of the present embodiment has good workability, when the adhesive sheet 1 is punched out, it can be suppressed that the adhesive overflows from the cut surface and leads to the Causes the adhesive to stick to the blade and other problems.

[display body]

As shown in FIG. 2, the display body 4 of the present embodiment includes the following structures: a first display body constituting member 51 (a display body constituting member) having a level difference at least on the surface on the side to which it is attached; and a second display body constituting member 52 (another display body constituting member); and the adhesive layer 2 which is positioned between these and which adheres the first display body constituting member 51 and the second display body constituting member 52 to each other. In the display body 4 of the present embodiment, the first display body constituent member 51 has a level difference on the surface on the adhesive layer 2 side, specifically, a level difference formed by the print layer 6 .

The adhesive layer 2 in the above-mentioned display body 4 is one that hardens the adhesive layer 2 (especially the third adhesive layer 23 ) of the above-mentioned adhesive sheet 1 by irradiating active energy rays (for convenience, the same name is used. and symbols). Here, an active energy ray means what has an energy quantum in an electromagnetic wave or a charged particle beam, and specifically, an ultraviolet-ray, an electron beam, etc. are mentioned. Among the active energy rays, ultraviolet rays, which are easy to handle, are particularly preferred.

Irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of ultraviolet rays is preferably about 50 to 1000 mW/cm ² . In addition, the light quantity is preferably 50-10000 mJ/cm ² , more preferably 80-5000 mJ/cm ² , and particularly preferably 200-2000 mJ/cm ² . On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 krad.

Regarding the irradiation of the active energy ray with respect to the adhesive layer 2 , after the first display component member 51 and the second display component member 52 are bonded to each other through the adhesive layer 2 , the first display component member 51 is interposed therebetween. and 2nd It is preferable to carry out the member which transmits an active energy ray among the member 52 of a display body.

When the active energy ray is irradiated to the adhesive layer 2, the active energy ray-curable compound (D) in the third adhesive layer 23 in particular is polymerized and cured. The adhesive layer 2 hardened by irradiation with active energy rays (in particular, the third adhesive layer 23 is hardened) is very excellent in anti-foaming properties and step followability under high temperature and high humidity.

As the display body 4, 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 4 may be a member constituting a part of these.

The first display body constituent member 51 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. These are usually rigid bodies. At this time, the printed layer 6 is generally formed in a frame shape on the side of the adhesive layer 2 in the first display body constituent member 51 .

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, on one or both sides of the above glass plate or plastic plate can be Various functional layers (transparent conductive films, metal layers, silicon oxide layers, hard coat layers, anti-glare layers, etc.) are provided, and optical members can be laminated. Also, the transparent conductive film and the metal layer may be patterned.

The second display body component 52 is an optical component, a display body module (eg, a liquid crystal (LCD) module, a light emitting diode (LED) module, an organic electro A light-emitting (organic EL) module, etc.), an optical member as a part of a display module, or a laminate including a display module 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.

It does not specifically limit about the material which comprises the printing layer 6, A well-known material for printing can be used. The thickness of the printed layer 6, 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 setting the lower limit value to be equal to or greater than the above-mentioned lower limit value, it is possible to sufficiently ensure the concealability of the wiring and the like from the observer's side. Moreover, 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. The upper limit value is equal to or less than the above-mentioned upper limit value, whereby deterioration of the step followability of the adhesive layer 2 with respect to the printed layer 6 can be prevented.

When the above-mentioned display body 4 is manufactured, as an example, one peeling sheet 31 of the adhesive sheet 1 is peeled off, and the exposed adhesive layer 2 of the adhesive sheet 1 is attached to the second one. 1. The surface on the side where the printed layer 6 of the body constituting member 51 exists. At this time, since the adhesive layer 2 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 6 .

After that, the other release sheet 32 is peeled off from the adhesive layer 2 of the adhesive sheet 1, and the exposed adhesive layer 2 of the adhesive sheet 1 and the second display body constituent member 52 are bonded together. Moreover, as another example, the bonding order of the 1st display body structure member 51 and the 2nd display body structure member 52 may be replaced.

In the above-mentioned display body 4, the adhesive layer 2 has excellent anti-foaming properties, so even when the display body 4 is placed under high temperature and high humidity conditions (for example, 85° C., 85% RH, 72 hours), it is When degassing occurs in the display element constituting member of the same configuration, the generation of bubbles, floating, peeling and other foaming phenomena at the interface between the adhesive layer 2 and the display element constituting member 51 and the display element constituting member 52 can also be suppressed.

In addition, in the above-mentioned display body 4, even under high temperature and high humidity conditions, the adhesive layer 2 is excellent in step followability, so even if the display body 4 is placed under high temperature and high humidity conditions (for example, 85°C, 85% RH) , 72 hours), the generation of air bubbles, floating, peeling, etc. in the vicinity of the step can also be 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 sheet 31 and the release sheet 32 in the adhesive sheet 1 may be omitted, and a desired optical member may be laminated instead of the release sheet 31 and/or the release sheet 32 . Furthermore, the adhesive layer 2 can be There are other layers between the first adhesive layer 21 and/or the second adhesive layer 22 and the third adhesive layer 23 in the Still another layer exists on the outside of the adhesive layer 22 (the release sheet 31 and the release sheet 32 side).

In addition, the first display body constituent member 51 may have steps other than the printed layer 6 . Furthermore, not only the first display body configuration member 51 but also the second display body configuration member 52 may be one having a level difference on the adhesive layer 2 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.

[Manufacturing Example 1]

-Preparation of a laminate having a first adhesive layer or a second adhesive layer-

(1) Preparation of (meth)acrylate polymer (A)

A (meth)acrylate polymer (A) was prepared by copolymerizing 60 parts by mass of 2-ethylhexyl acrylate, 20 parts by mass of methyl methacrylate, and 20 parts by mass of 2-hydroxyethyl acrylate. As a result of measuring the molecular weight of this (meth)acrylate polymer (A) by the method mentioned later, the weight average molecular weight (Mw) was 600,000.

(2) Preparation of adhesive composition P

100 parts by mass of the (meth)acrylate polymer (A) obtained in the above process (1) (solid content conversion value; the same below), trimethylolpropane-modified toluene as the crosslinking agent (B) 0.25 parts by mass of diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L"), and 3-glycidyloxypropyltrimethoxysilane ( Shin-Etsu Chemical Co., Ltd., product name "KBM403") 0.30 parts by mass was mixed and sufficiently stirred, and diluted with methyl ethyl ketone to obtain a coating of the adhesive composition P having a solid content concentration of 35% by mass. cloth solution.

Here, Table 1 shows each compounding (solid content conversion value) of the adhesive composition when the (meth)acrylate polymer is used as 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 polymer]

2EHA: 2-ethylhexyl acrylate

MMA: methyl methacrylate

HEA: 2-hydroxyethyl acrylate

BA: n-butyl acrylate

IBXMA: isobornyl methacrylate

IBXA: Isobornyl Acrylate

ACMO: 4-Propenylmorpholine

AA: Acrylic

[Crosslinking agent]

TDI series: Trimethylolpropane-modified toluene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L")

Epoxy system: 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane (manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC., product name "TETRAD C-5")

(3) Production of laminated body

Use a knife coater to coat the adhesive composition obtained in the above process (2) The coating solution of material P was applied to the peeling-treated surface of a heavy-peel release sheet (manufactured by Lintec Corporation, product name "SP-PET752150"), and then heat-treated at 90° C. for 1 minute to form a coating layer (thickness: 25 μm). ), the peeling treatment surface of the heavy peeling type peeling sheet is formed by performing peeling treatment on one side of the polyethylene terephthalate film with a silicone-based peeling agent. Similarly, the coating solution of the adhesive composition obtained in the above-mentioned process 2 was coated on the peeling treated surface of a light peeling type release sheet (manufactured by Lintec Corporation, product name "SP-PET382120") using a knife coater. , and heat treatment at 90°C for 1 minute to form a coating layer (thickness: 25 μm). It is formed by carrying out a peeling process.

Next, the heavy release type release sheet with the coating layer obtained above and the light release type release sheet with the coating layer obtained above were attached in such a way that the two coating layers were in contact with each other, and were placed on the It aged for 7 days under the conditions of 23 degreeC, 50%RH, and produced the laminated body which consists of the following structure, ie, the heavy release type release sheet/adhesive layer (thickness: 50 micrometers)/light release type release sheet. Moreover, this adhesive layer consists of an active energy ray non-curable adhesive, and corresponds to a 1st adhesive layer and a 2nd adhesive layer.

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

[Production Example 2 to Production Example 3]

As shown in Table 1, the types and ratios of the monomers constituting the (meth)acrylate polymer (A) and the weight of the (meth)acrylate polymer (A) A layered body was produced in the same manner as in Production Example 1, except that the average molecular weight was changed.

[Production Example 4]

-Preparation of laminated body with 3rd adhesive layer-

(1) Preparation of (meth)acrylate polymer (C)

(Meth)acrylate was prepared by copolymerizing 60 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of isobornyl acrylate, 10 parts by mass of 4-acrylomorpholine, and 20 parts by mass of 2-hydroxyethyl acrylate Polymer (C). As a result of measuring the molecular weight of this (meth)acrylate polymer (C) by the method mentioned later, the weight average molecular weight (Mw) was 500,000.

(2) Preparation of adhesive composition Q

The following components are mixed and fully stirred, and diluted with methyl ethyl ketone to obtain a coating solution of the adhesive composition Q with a solid content concentration of 48% by mass, that is, the (1) obtained in the above-mentioned process (1). 100 parts by mass of meth)acrylate polymer (C), ε-caprolactone-modified tris-(2-acrylooxyethyl)isocyanurate (Shin -Nakamura Chemical Co., Ltd. product name "NK ester A-9300-1CL") 5.0 parts by mass, as a photopolymerization initiator (E), in a mass ratio of 1:1 p-benzophenone and 1- 0.50 parts by mass of hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name "Irgacure 500"), trimethylolpropane-modified toluene diisocyanate (Nippon Polyurethane Industry Co., Ltd., product name "Coronate L") 0.25 parts by mass, and 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KBM") as a silane coupling agent -403”) 0.30 parts by mass.

(3) Production of laminated body

Using the coating solution of the adhesive composition Q obtained in the above-mentioned process (2), and in the same manner as the above-mentioned adhesive composition P, a heavy peeling type release sheet/adhesive having the following structure was produced. Layer (thickness: 50 μm)/a layered product composed of a light release type release sheet. Moreover, this adhesive layer consists of an active energy ray-curable adhesive, and corresponds to a 3rd adhesive layer.

[Manufacturing Example 5]

As shown in Table 1, the types and ratios of the monomers constituting the (meth)acrylate polymer (A), the weight average molecular weight of the (meth)acrylate polymer (A), and the active energy ray-curable compound A laminate was produced in the same manner as in Production Example 4, except that the ratio of (D), the ratio of the photopolymerization initiator (E), and the type and ratio of the crosslinking agent (B) were changed.

Here, the above-mentioned weight average molecular weight (Mw) is the weight average molecular weight in terms of polystyrene measured (GPC measurement) using gel permeation chromatography (GPC) under the following conditions.

<Measurement conditions>

. GPC measurement device: HLC-8020 manufactured by TOSOH CORPORATION

. GPC column (passed in the following order): TOSOH CORPORATION

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

. Assay solvent: tetrahydrofuran

. Measurement temperature: 40℃

[Example 1]

The light release type release sheet was peeled off from the laminate obtained in Production Example 1, and the light release type release sheet was peeled off from the laminate obtained in Production Example 4, and the exposed first adhesive layer was placed in contact with each other. By bonding with the third adhesive layer, the heavy-release release sheet is peeled off from the third adhesive layer. Next, the light release type release sheet was peeled off from the laminate obtained in Production Example 1, and the exposed second adhesive layer and the third adhesive layer were bonded together so as to be in contact with each other to obtain an adhesive sheet. The pressure-sensitive adhesive sheet is formed by sandwiching the pressure-sensitive adhesive layer composed of the first pressure-sensitive adhesive layer, the third pressure-sensitive adhesive layer, and the second pressure-sensitive pressure-sensitive adhesive layer between two heavy-peel release sheets.

[Example 2 to Example 6, Comparative Example 1 to Comparative Example 7]

The adhesive layers of the laminates produced in Production Examples 1 to 5 were laminated in the lamination order shown in Table 2, and an adhesive sheet was produced in the same manner as in Example 1. Here, the thickness of each adhesive bond layer was changed so that it might become the thickness shown in Table 2, respectively.

[Test Example 1] (Measurement of gel fraction)

The laminates produced in Production Examples 1 to 5 were cut to a size of 80 mm × 80 mm, the adhesive layer was wrapped in a polyester mesh (mesh size 200), and the mass was weighed by a precision balance, and then reduced. Go to the individual mass of the net above, and thereby 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. put this The mass at the time is set to M2. The gel fraction (%) is represented by (M2/M1)×100. The results are shown in Table 3.

Moreover, about the adhesive layer of the laminated body of Production Example 4 and Production Example 5, the gel fraction before and after irradiation with ultraviolet rays (irradiated from the heavy release type release sheet side) to the adhesive layer was measured. In the table, the result before ultraviolet irradiation is described as "before UV", and the result after ultraviolet irradiation is described as "after UV" (hereinafter, the same). The irradiation conditions of the ultraviolet rays are as follows.

<Ultraviolet irradiation conditions>

‧Using the electrodeless lamp H bulb made by Fusion, Co., Ltd.

‧Illumination 500mW/cm ² , light quantity 200mJ/cm ²

‧Using "UVPF-36" manufactured by EYE GRAPHICS CO., LTD. as UV illuminance and light meter

[Test Example 2] (Measurement of Adhesion)

The light release type release sheet was peeled off from the laminates produced in Production Examples 1 to 5, and the exposed adhesive layer was attached to a polyethylene terephthalate (PET) film (TOYOBO CO., LTD., product name "PET A4300", thickness: 100 μm) of the easy-bonding layer 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, the heavy-release type release sheet was peeled off from the above-mentioned sample, and the exposed adhesive layer was attached to soda lime glass (manufactured by Nippon Sheet Glass Co., Ltd.), and then used Kurihara The autoclave manufactured by Manufactory Inc. was pressurized at 0.5 MPa and 50° C. for 20 minutes. Then, after standing for 24 hours under the conditions of 23° C. and 50% RH, a tensile tester (ORIENTEC) was used. Co., LTD., Tensilon) The adhesive force (N/25 mm) 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 3.

In addition, the laminates of Production Example 4 and Production Example 5 were attached to soda lime glass and pressurized with an autoclave in the same manner as above, and then the adhesive layer was irradiated with ultraviolet rays through the soda lime glass, and then the same The adhesive force after standing for 24 hours was also measured in the same manner as above. The irradiation conditions of ultraviolet rays were the same as those in Test Example 1.

[Test Example 3] (Measurement of storage elastic modulus (G'))

The adhesive layers of the laminates produced in Production Examples 1 to 5 were laminated in a plurality of layers to obtain a laminate having a thickness of 3 mm. A cylinder having a diameter of 8 mm (height 3 mm) was punched out from the obtained laminated body of the adhesive layer, and this was used as a sample.

The storage elastic modulus (G') (MPa) was measured by the torsional shear method in accordance with JIS K7244-6 using a viscoelasticity measuring device (manufactured by REOMETRIC, DYNAMIC ANALAYZER) under the following conditions. The results are shown in Table 3.

Measurement frequency: 1Hz

Measurement temperature: 23℃

In addition, with respect to the adhesive layers of the laminates of Production Examples 4 and 5, the storage elastic modulus (G') was measured before and after the laminate of the adhesive layers was irradiated with ultraviolet rays. The irradiation conditions of ultraviolet rays were the same as those in Test Example 1.

[Test Example 4] (Measurement of 100% modulus)

The adhesive layers of the laminates produced in Production Examples 1 to 5 were laminated in a plurality of layers, and after setting the total thickness to 800 μm, cut out a width of 10 mm×length of 75 mm sample. The above-mentioned sample was set in a tensile tester (manufactured by ORIENTEC Co., LTD., product name "Tensilon") so that the sample measurement site was 10 mm in width x 25 mm in length (tensile direction), and was heated at 23° C., 50% Under the environment of RH, the tensile tester is used to stretch at a stretching speed of 200 mm/min, and the stress-bending line (SS curve) is used, and the stress value at which the stretching ratio becomes 100% is regarded as the 100% modulus (kPa ) to calculate (measure). The results are shown in Table 3.

In addition, the 100% modulus (kPa) before and after the laminated body of the adhesive layer was irradiated with ultraviolet rays was measured about the adhesive layer of the laminated body of manufacture example 4 and manufacture example 5. The irradiation conditions of ultraviolet rays were the same as those in Test Example 1.

In addition, the 100% modulus (kPa) was also measured by the same method as above for the adhesive layers of the adhesive sheets obtained in Examples 1 to 6 and Comparative Examples 6 to 7 (for Comparative Examples 1 to Comparative Example 5 are the same as the results of Production Example 1 to Production Example 5, so the test is omitted). However, with respect to the examples and comparative examples other than Example 2, the adhesive layer (three-layer structure) was laminated in a plurality of layers, and the total thickness was set to 750 μm. The results are shown in Table 4. Moreover, the 100% modulus (kPa) before and after irradiating an ultraviolet-ray to the adhesive bond layer of the adhesive bond layer of the adhesive sheet obtained in Examples 1-6 and Comparative Example 6 was measured. The irradiation conditions of ultraviolet rays were the same as those in Test Example 1.

[Test Example 5] (Evaluation of anti-foaming property)

A transparent conductive film of polyethylene terephthalate film (manufactured by OIKE & Co., Ltd., ITO film, thickness: 125 μm) provided with a transparent conductive film composed of tin-doped indium oxide (ITO) on one side and Polycarbonate (PC) sheet (made by MITSUBISHI GAS CHEMICAL COMPANY, INC., iupilon sheet MR58, thickness: 1mm) or acrylic sheet composed of polymethyl methacrylate (PMMA) (made by MITSUBISHI GAS CHEMICAL COMPANY, INC., iupilon sheet MR200, thickness: 1 mm) to sandwich the adhesive layers of the laminates produced in Production Examples 1 to 5, Examples 1 to 6 and Comparative Example 1 ~ The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in Comparative Example 7 to obtain a laminate.

The obtained layered body was subjected to an autoclave treatment under the conditions of 50° C. and 0.5 MPa for 30 minutes. Then, the adhesive layer was cured by irradiating the adhesive layer with ultraviolet rays under the same ultraviolet irradiation conditions as in Test Example 1 through a PC board or an acrylic plate (except for the adhesive layers in Production Examples 1 to 3, Comparative Example 1) ~ Adhesive layer of Comparative Example 3 and Comparative Example 7).

The sample obtained as described above was left to stand at normal pressure, 23°C, and 50% RH for 15 hours. Next, it was stored for 72 hours under the durability conditions of 85° C. and 85% RH. After that, the presence or absence of air bubbles, floating or peeling in the adhesive layer was confirmed by visual observation, and the foaming resistance was evaluated according to the following criteria. The results are shown in Table 3 and Table 4.

◎...No bubbles, floating or peeling at all.

○... Only bubbles with a diameter of 0.1 mm or less were generated.

×... bubbles larger than 0.1 mm in diameter, floated or peeled off.

[Test Example 6] (Measurement of step follow-up rate)

On the surface of a glass plate (manufactured by NSG Precision Co., Ltd., product name "Corning Glass Eagle XG", length 90 mm × width 50 mm × thickness 0.5 mm), the coating thicknesses were 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, screen printing UV-curable ink (Teikoku Printing Inks Mfg.Co. , Ltd., product name "POS-911 ink"). Next, ultraviolet rays (80W/cm ² , two metal halide lamps, lamp height 15cm, belt speed 10~15m/min) were irradiated to harden the above-mentioned UV-curable ink printed to produce a step with a difference caused by printing. (Height of step: any of 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm) glass plate with step difference.

One release sheet was peeled off from the laminates produced in Production Examples 1 to 5, and the adhesive sheets obtained in Examples and Comparative Examples, and the exposed adhesive layer was attached to a polyterephthalate having an easily adhesive layer. An easily bonding layer of an ethylene formate film (manufactured by TOYOBO CO., LTD., product name "PET A4300", thickness: 100 μm). Next, another release sheet is peeled off to reveal the adhesive layer. Then, using a laminator (manufactured by FUJIPLA Inc., product name "LPD3214"), the above-mentioned laminate was laminated on each stepped glass plate so that the adhesive layer covered the entire printed surface of the frame. After that, autoclave treatment was performed under the conditions of 50° C. and 0.5 MPa for 30 minutes.

Through the PET film, under the same ultraviolet irradiation conditions as in Test Example 1, the above-mentioned adhesive layer was irradiated with ultraviolet rays to harden the adhesive layer (except for the adhesive layers of Production Examples 1 to 3 and Comparative Examples 1 to 1). Adhesive layer of Comparative Example 3 and Comparative Example 7).

The sample for evaluation obtained as described above was stored under high temperature and high humidity conditions of 85° C. and 85% RH for 72 hours (endurance test), and then the step followability was evaluated. The level difference followability is judged by whether the printing level difference is completely filled by the adhesive layer. When air bubbles, floating, peeling, etc. are observed at the interface between the printing level difference and the adhesive layer, it is judged that it is impossible. Follow the printing step difference. Here, the step followability was evaluated as a step follow rate (%) represented by the following formula. The results are shown in Table 3 and Table 4.

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

[Test Example 7] (Evaluation of workability)

The adhesive sheets obtained in Examples and Comparative Examples were cut with an automatic cutter (manufactured by Ogino Seisakusho Co., Ltd., product name "Super Cutter OSS-PN1 Type N-L"). The cut surface (length: 100 mm) of the cut adhesive sheet was confirmed by visual observation, and the workability was evaluated according to the following criteria. The results are shown in Table 4.

○: No overflow phenomenon in the adhesive layer

×: There is overflow in the adhesive layer

【Table 2】

As can be seen from Table 4, the adhesive sheets obtained in the examples were excellent in both step followability and anti-foaming properties, and were good in processability.

【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

2‧‧‧Adhesive layer

21‧‧‧First Adhesive Layer

22‧‧‧Second adhesive layer

23‧‧‧The third adhesive layer

31‧‧‧Peeling sheet

32‧‧‧Peeling sheet

Claims (8)

An adhesive sheet comprising an adhesive layer, characterized in that: the adhesive layer comprises: a first adhesive layer, which is an outer layer on one surface side; a second adhesive layer, which is an outer layer on the other surface side; and The third adhesive layer is located between the first adhesive layer and the second adhesive layer as an intermediate layer, and the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are acrylic An adhesive, the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are respectively 0.1 MPa or more and 0.5 MPa or less, and the aforementioned The third adhesive layer is composed of the active energy ray-curable adhesive before curing, and the storage elastic modulus (G') at 23°C of the adhesive constituting the first adhesive layer and the second adhesive The storage elastic modulus (G') at 23°C of the adhesive of the layer is lower than the storage elastic modulus (G') at 23°C before hardening of the active energy ray-curable adhesive. . An adhesive sheet comprising an adhesive layer, characterized in that: the adhesive layer comprises: a first adhesive layer, which is an outer layer on one surface side; a second adhesive layer, which is an outer layer on the other surface side; and The third adhesive layer is located between the first adhesive layer and the second adhesive layer as an intermediate layer, and the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are acrylic It is an adhesive, the 100% modulus of the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are respectively 60 kPa or more and 150 kPa or less, and the third adhesive layer is composed of active energy rays before curing. Curable adhesive composition, compared with the 100% modulus of the adhesive constituting the first adhesive layer and the 100% modulus of the adhesive constituting the second adhesive layer, the curing of the active energy ray-curable adhesive The former 100% modulus is lower. The adhesive sheet according to claim 1 or 2, wherein the adhesive constituting the first adhesive layer and the adhesive constituting the second adhesive layer are active energy ray non-curable adhesives. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the ratio of the total thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer to the thickness of the third pressure-sensitive adhesive layer is 0.3 or more and 5 or less . The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the total thickness of the pressure-sensitive adhesive layer is 50 μm or more and 300 μm or less. The adhesive sheet according to claim 1 or 2, wherein the adhesive sheet is used for laminating a display element constituting member and another display element constituting member having a level difference at least on one side surface to be attached. The adhesive sheet according to claim 1 or 2, characterized in that the adhesive sheet comprises two release sheets, The adhesive layer is sandwiched between the two 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 having a level difference at least on the surface of one side to be attached; another display body constituting member; The body constituting members are adhered to each other, wherein the adhesive layer is an adhesive layer formed by hardening the adhesive layer of the adhesive sheet described in claim 1 or 2.

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