JP2022039945A - Photocurable adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet appropriate for manufacturing a self-luminous type display device such as a mini/micro LED display device with improved antireflection function for metal wiring, etc. and contrast, as well as simultaneously realizing excellent step absorbency and processability.SOLUTION: A photocurable adhesive sheet includes an adhesive layer configured to be cured by radiation exposure. The adhesive layer includes a coloring agent. In the adhesive layer, a maximum value of transmissivity at wavelength 200 to 400 nm is larger than a maximum value of transmissivity at wavelength 400 to 700 nm. A storage modulus (G'b85) of the uncured adhesive layer at 85°C is less than 65 kPa. A storage modulus (G'a10) of the uncured adhesive layer at 10°C and the storage modulus (G'b85) of the uncured adhesive layer at 85°C satisfy a relational expression (1): 3.3<G'a10/G'b85 (1).SELECTED DRAWING: None

Description

The present invention relates to a photocurable pressure-sensitive adhesive sheet. More specifically, the present invention relates to a photocurable adhesive sheet suitable for sealing a light emitting element of a self-luminous display device such as a mini / micro LED.

In recent years, as a next-generation display device, a self-luminous display device represented by a mini / micro LED display device (Mini / Micro Light Emitting Diode Display) has been devised. As a basic configuration of a mini / micro LED display device, a substrate in which a large number of minute LED light emitting elements (LED chips) are arranged at high density is used as a display panel, and the LED chips are sealed with a sealing material. A cover member such as a resin film or a glass plate is laminated on the outermost layer.

There are several self-luminous display devices such as mini / micro LED display devices, such as a white backlight system, a white emission color filter system, and an RGB system. The white emission color filter system and the RGB system are sealed. A black-colored pressure-sensitive adhesive may be used as the material (see, for example, Patent Documents 1 to 3).
The black adhesive contributes to color mixing prevention and contrast improvement by filling the space between the RGB LED chips arranged on the display panel board, and also contributes to the prevention of color mixing and the improvement of contrast, and also the metal wiring and ITO arranged on the display panel board. This is because it is possible to prevent reflection of metal oxides and the like.

In mini / micro LED display devices, LED chips are densely spread on the substrate, and there are many fine steps in the gaps between the LED chips, making it a sealing material used in mini / micro LED display devices. Is required to have the ability to fill these steps, that is, excellent step absorption (also referred to as "step followability"). Therefore, the black pressure-sensitive adhesive needs to be designed to exhibit high fluidity in order to improve step absorption.

On the other hand, although the pressure-sensitive adhesive showing high fluidity is excellent in step absorption, there is a problem that processability such as shape stability and handleability is deteriorated. For example, in a laminate having a pressure-sensitive adhesive layer showing high fluidity, adhesive chipping occurs during cutting, and the pressure-sensitive adhesive layer tends to protrude or sag from the edges during storage, and foreign matter adheres to the protruding pressure-sensitive adhesive layer. This may cause problems such as process contamination.

A photocurable pressure-sensitive adhesive (hybrid pressure-sensitive adhesive) is known as a pressure-sensitive adhesive that achieves both step absorption and processability (see, for example, Patent Document 4). With hybrid adhesives, it is possible to first make a semi-cured state with high fluidity and excellent step absorption so that it sufficiently follows the step, and then irradiate light to complete the curing and improve workability. Has advantages.

JP-A-2019-204905 Japanese Unexamined Patent Publication No. 2017-203810 Japanese Patent Publication No. 2018-523854 International Publication WO2016 / 170875

However, for example, when carbon black or the like is blended with a hybrid pressure-sensitive adhesive and colored, there is a problem that light cannot pass through the pressure-sensitive adhesive, so that curing is hindered and it becomes difficult to improve processability.

The present invention has been conceived under the above circumstances, and an object of the present invention is to have an antireflection function such as metal wiring and self-luminous light emission of a mini / micro LED display device having improved contrast. It is an object of the present invention to provide an adhesive sheet which is suitable for manufacturing a type display device and has excellent step absorption and processability.

As a result of diligent studies to achieve the above object, the present inventors colored the pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive sheet so as to have absorbency in the visible light region but high transparency in the ultraviolet region. By doing so, it was found that the antireflection function of metal wiring and the like in the self-luminous display device and the contrast are improved, and that excellent step absorption and processability can be achieved at the same time. The present invention has been completed based on these findings.

The first aspect of the present invention provides a photocurable pressure-sensitive adhesive sheet. That is, the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention contains a pressure-sensitive adhesive layer that is cured by irradiation. In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the pressure-sensitive adhesive layer before curing is in a semi-cured state with high fluidity and exhibits excellent step absorption. Therefore, when the light emitting elements (LED chips) are attached to the display panel arranged at high density, they sufficiently follow the minute steps between the light emitting elements (LED chips) and adhere to each other without leaving any bubbles. On the other hand, the adhesive layer after curing exhibits excellent processability. Therefore, it is possible to prevent the adhesive layer containing the adhesive layer after curing from being chipped during cutting, and the adhesive layer from sticking out from the edges or dripping during storage.

In the pressure-sensitive adhesive layer in the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm. The pressure-sensitive adhesive layer has high absorption to visible light (wavelength 400 to 700 nm) and excellent light-shielding property. The structure in which the adhesive layer has excellent light-shielding property against visible light is such that the adhesive layer filled in the minute steps between the LED chips without gaps is arranged so as to prevent reflection by metal wiring or the like on the display panel. It is preferable in that it prevents color mixing between the light emitting elements (LED chips) and improves the contrast. On the other hand, the pressure-sensitive adhesive layer has high transparency to ultraviolet rays (wavelength 200 to 400 nm). The configuration in which the pressure-sensitive adhesive layer has excellent transparency to ultraviolet rays is preferable in that the curing reaction proceeds by irradiating the pressure-sensitive adhesive layer with ultraviolet rays, and the processability of the pressure-sensitive adhesive layer is improved. That is, the structure in which the maximum value of the transmittance of the pressure-sensitive adhesive layer at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm has excellent light-shielding property against visible light and a curing reaction by ultraviolet irradiation. It is preferable in that both can be achieved.

The pressure-sensitive adhesive layer in the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention contains a colorant. The colorant is preferably a colorant in which the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm. This configuration is preferable in order to realize that the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm in the pressure-sensitive adhesive layer.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer before curing at 85 ° C. is less than 65 kPa. Such a configuration is preferable in that the pressure-sensitive adhesive layer before curing exhibits excellent step absorption.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the storage elastic modulus (G'a10) of the pressure-sensitive adhesive layer after curing at 10 ° C. and the storage elastic modulus of the pressure-sensitive adhesive layer before curing at 85 ° C. G'b85) satisfies the following relational expression (1).
3.3 <G'a10 / G'b85 (1)
Such a configuration is preferable in that the pressure-sensitive adhesive layer before curing exhibits excellent step absorption and the pressure-sensitive adhesive layer after curing exhibits excellent processability.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, it is preferable that the curing by irradiation with radiation is the curing by irradiation with ultraviolet rays having an integrated light amount of 3000 mJ / cm ² . This configuration is preferable in that the pressure-sensitive adhesive layer is cured by irradiation with ultraviolet rays and exhibits excellent processability.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the storage elastic modulus (G'a10) of the pressure-sensitive adhesive layer after curing at 10 ° C. is preferably 90 kPa or more. This configuration is preferable in that the pressure-sensitive adhesive layer after curing exhibits excellent processability.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, it is preferable that the pressure-sensitive adhesive layer contains a base polymer, a cross-linking agent, and a photopolymerization initiator. In this configuration, the base polymer preferably contains an acrylic polymer. In that case, it is preferable that the cross-linking agent contains a polyfunctional (meth) acrylate. These configurations are preferable in that the pressure-sensitive adhesive layer exhibits excellent processability by forming a crosslinked structure and curing by the reaction of the cross-linking agent and the photopolymerization initiator by irradiation. In this configuration, the pressure-sensitive adhesive layer constitutes a hybrid pressure-sensitive adhesive, and the base polymer is semi-cured to the extent that it is excellent in step absorption.

In the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, the pressure-sensitive adhesive layer is a single layer having two opposing main surfaces made of the base polymer, and the pressure-sensitive adhesive layer of the single layer is thickened. The concentration of the cross-linking agent and / or the photopolymerization initiator in the region to which the first main surface of one of the two main surfaces belongs when the two main surfaces are divided into two equal parts in the direction, and the second main surface of the other. A configuration in which the concentrations of the cross-linking agent and / or the photopolymerization initiator in the region to which the material belongs is different is preferable. In this configuration, it is preferable that the single pressure-sensitive adhesive layer has a concentration gradient of the cross-linking agent and / or the photopolymerization initiator in the thickness direction.
The photocurable pressure-sensitive adhesive sheet according to these aspects is preferably produced by a method including the following steps.
Forming a single adhesive layer formed by the base polymer,
The pressure-sensitive adhesive layer is cured and
Prepare a solution of the cross-linking agent and / or the photopolymerization initiator.
The solution is applied to one surface of the cured pressure-sensitive adhesive layer, and the cross-linking agent and / or the photopolymerization initiator contained in the solution permeates from the one surface of the pressure-sensitive adhesive layer in the thickness direction. Let me
The pressure-sensitive adhesive layer is dried.

In the above configuration, a solution of the cross-linking agent and / or the photopolymerization initiator is applied to one surface of the pressure-sensitive adhesive layer and permeated, whereby the cross-linking agent and / or the light is applied to the front and back surfaces of the pressure-sensitive adhesive layer. This is due to the difference in the concentration of the polymerization initiator. This configuration is preferable in order to realize excellent step absorption of the pressure-sensitive adhesive layer before curing and excellent processability of the pressure-sensitive adhesive layer after curing.

Further, in the photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention, it is preferable that the pressure-sensitive adhesive layer contains a polymer having a benzophenone structure in a side chain. In this configuration, the pressure-sensitive adhesive layer is preferably a cured product of a pressure-sensitive adhesive composition containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain. This configuration is preferable in that the pressure-sensitive adhesive layer before curing exhibits excellent step absorption, and the benzophenone structure forms a crosslinked structure and is cured by irradiation with ultraviolet rays to realize excellent processability.

Further, the second side surface of the present invention is a self-luminous display device including a display panel in which a plurality of light emitting elements are arranged on one side of a substrate and a photocurable adhesive sheet on the first side surface of the present invention. The present invention provides a self-luminous display device in which the light emitting element of the display panel is sealed with the pressure-sensitive adhesive layer of the photo-curable pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive layer is cured. In the self-luminous display device on the second side surface of the present invention, the display panel may be an LED panel in which a plurality of LED chips are arranged on one side of a substrate. In such a configuration, in the self-luminous display device on the second side surface of the present invention, a pressure-sensitive adhesive layer having excellent light-shielding properties filled in fine steps between light-emitting elements (LED chips) without gaps is metal wiring on a substrate. It is preferable in that it can prevent reflection such as, prevent RGB color mixing, and improve contrast.

The self-luminous display device according to the second aspect of the present invention can be manufactured by a method including the following steps.
A step of laminating a pressure-sensitive adhesive layer of a photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention on a display panel in which a plurality of light-emitting elements are arranged on one side of a substrate, and sealing the light-emitting elements with the pressure-sensitive adhesive layer. And the step of irradiating the pressure-sensitive adhesive layer with radiation to cure it.
Since the pressure-sensitive adhesive layer before curing has excellent step absorption, it sufficiently follows the minute steps between the light emitting elements and adheres without leaving any bubbles. Then, the pressure-sensitive adhesive layer is cured by irradiating it with radiation, resulting in excellent processability.
The radiation is preferably ultraviolet rays in which the pressure-sensitive adhesive layer exhibits transparency.

Since the photocurable adhesive sheet of the present invention has an adhesive layer having a high light-shielding property against visible light and excellent step absorption, it can be used in the manufacture of a self-luminous display device to provide a step between a plurality of light emitting elements. Is filled without gaps, prevents reflection from metal wiring, suppresses color mixing between a plurality of light emitting elements, and improves contrast. In addition, the pressure-sensitive adhesive layer, which has excellent transparency to ultraviolet rays, is cured by irradiating it with radiation to improve workability. Is suppressed. Therefore, by using the photocurable adhesive sheet of the present invention for manufacturing a self-luminous display device, it is possible to efficiently manufacture a self-luminous display device having an improved antireflection function such as metal wiring and contrast. can.

FIG. 1 is a diagram (cross-sectional view) schematically showing an embodiment of the photocurable pressure-sensitive adhesive sheet of the present invention. FIG. 2 is a diagram (cross-sectional view) schematically showing a step for carrying out one embodiment of the method for producing a photocurable pressure-sensitive adhesive sheet of the present invention. FIG. 3 is a diagram (cross-sectional view) schematically showing an embodiment of the photocurable pressure-sensitive adhesive sheet of the present invention. FIG. 4 is a schematic view (cross-sectional view) showing an embodiment of the self-luminous display device (mini / micro LED display device) of the present invention. FIG. 5 is a schematic view (cross-sectional view) showing a process for implementing an embodiment of the method for manufacturing a self-luminous display device (mini / micro LED display device) of the present invention.

The embodiments of the present invention will be described with reference to the drawings as necessary, but the present invention is not limited thereto and is merely an example.

[Photo-curable adhesive sheet]
The photocurable pressure-sensitive adhesive sheet on the first side surface of the present invention contains a pressure-sensitive adhesive layer that is cured by irradiation, the pressure-sensitive adhesive layer contains a colorant, and the pressure-sensitive adhesive layer has a transmittance of a wavelength of 200 to 400 nm. The maximum value is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm, the storage elasticity (G'b85) of the pressure-sensitive adhesive layer at 85 ° C. before curing is less than 65 kPa, and the pressure-sensitive adhesive layer after curing. The storage elasticity (G'a10) at 10 ° C. and the storage elasticity (G'b85) at 85 ° C. before curing satisfy the following relational expression (1).
3.3 <G'a10 / G'b85 (1)

In the present specification, the photocurable pressure-sensitive adhesive sheet according to the first aspect of the present invention may be simply referred to as "photo-curable pressure-sensitive adhesive sheet A". Further, in the present specification, the adhesive layer satisfying the following (a) to (d) may be referred to as "adhesive layer A".
(A) It is cured by irradiation.
(B) The maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm.
(C) The storage elastic modulus (G'b85) at 85 ° C. before curing is less than 65 kPa.
(D) The storage elastic modulus (G'a10) at 10 ° C. after curing and the storage elastic modulus (G'b85) at 85 ° C. before curing satisfy the following relational expression (1).
3.3 <G'a10 / G'b85 (1)

The "adhesive sheet" shall include the meaning of "adhesive tape". That is, the photocurable adhesive sheet A may be an adhesive tape having a tape-like form.

The form of the photocurable pressure-sensitive adhesive sheet A is not particularly limited as long as it has a pressure-sensitive adhesive surface formed by the surface of the pressure-sensitive adhesive layer A. The photocurable pressure-sensitive adhesive sheet A may be a single-sided pressure-sensitive adhesive sheet having only one side as a pressure-sensitive adhesive surface, or may be a double-sided pressure-sensitive adhesive sheet having both sides having adhesive surfaces. When the photocurable pressure-sensitive adhesive sheet A is a double-sided pressure-sensitive adhesive sheet, the photo-curable pressure-sensitive adhesive sheet A may have a form in which both pressure-sensitive adhesive surfaces are provided by the pressure-sensitive adhesive layer A, or one of the pressure-sensitive adhesive surfaces is provided. It may have a form provided by the pressure-sensitive adhesive layer A and the other pressure-sensitive surface is provided by a pressure-sensitive adhesive layer (other pressure-sensitive adhesive layer) other than the pressure-sensitive adhesive layer A. From the viewpoint of adhering the adherends to each other, a double-sided pressure-sensitive adhesive sheet is preferable, and more preferably, a double-sided pressure-sensitive adhesive sheet in which both sides of the sheet are the surfaces of the pressure-sensitive adhesive layer A.

The photocurable pressure-sensitive adhesive sheet A is a pressure-sensitive adhesive sheet having no base material (base material layer), that is, a so-called "base material-less type" pressure-sensitive adhesive sheet (sometimes referred to as "base material-less pressure-sensitive adhesive sheet"). It may be an adhesive sheet having a base material (sometimes referred to as "adhesive sheet with a base material"). The base material-less pressure-sensitive adhesive sheet in the present invention includes, for example, a double-sided pressure-sensitive adhesive sheet composed of only the pressure-sensitive adhesive layer A and both sides composed of the pressure-sensitive adhesive layer A and another pressure-sensitive adhesive layer (adhesive layer other than the pressure-sensitive adhesive layer A). Adhesive sheet can be mentioned. The pressure-sensitive adhesive sheet with a base material in the present invention includes, for example, a single-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer A on one side of the base material, a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer A on both sides of the base material, and a base material. Examples thereof include a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer A on one surface side and another pressure-sensitive adhesive layer on the other side.

Among the above, from the viewpoint of improving the optical characteristics, a base material-less pressure-sensitive adhesive sheet is preferable, and a base material-less double-sided pressure-sensitive adhesive sheet (base material-less double-sided pressure-sensitive adhesive sheet) having only the pressure-sensitive adhesive layer A and having no base material is preferable. The case where the pressure-sensitive adhesive sheet A is a pressure-sensitive adhesive sheet having a base material is not particularly limited, but from the viewpoint of processability, a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer A on both sides of the base material (double-sided pressure-sensitive adhesive with a base material). Sheet) is preferable.

The above-mentioned "base material (base material layer)" means that when the photocurable pressure-sensitive adhesive sheet A is used (attached) to an adherend (optical member or the like), it is attached to the adherend together with the pressure-sensitive adhesive layer. It does not include the release film (separator) that is peeled off when the adhesive sheet is used (attached).

As described above, the photocurable pressure-sensitive adhesive sheet A may be a pressure-sensitive adhesive sheet with a base material. Examples of such a substrate include various optical films such as a plastic film, an antireflection (AR) film, a polarizing plate, and a retardation plate. Examples of the material such as the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethylmethacrylate (PMMA), polycarbonates, triacetylcellulose (TAC), polysulfone, polyallylates, and polyimides. Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "Arton" (cyclic olefin polymer, manufactured by JSR Co., Ltd.), trade name "Zeonoa" (cyclic olefin polymer, Nippon Zeon Co., Ltd.) Examples thereof include plastic materials such as cyclic olefin-based polymers such as "manufactured by the company". In addition, these plastic materials may be used individually or in combination of 2 or more types.

The substrate is preferably transparent. The total light transmittance (according to JIS K7361-1) in the visible light wavelength region of the base material is not particularly limited, but is preferably 85% or more, more preferably 88% or more. The haze of the base material (according to JIS K7136) is not particularly limited, but is preferably 1.5% or less, more preferably 1.0% or less. Examples of such a transparent base material include PET films and non-oriented films such as the trade name "Arton" and the trade name "Zeonoa".

The thickness of the base material is not particularly limited, but is preferably 12 to 75 μm. The base material may have either a single layer or a plurality of layers. Further, the surface of the base material is known to have, for example, antireflection treatment (AR treatment), antireflection treatment such as antiglare treatment, physical treatment such as corona discharge treatment and plasma treatment, and chemical treatment such as undercoating treatment. Conventional surface treatments may be appropriately applied.

As described above, the photocurable pressure-sensitive adhesive sheet A may have another pressure-sensitive adhesive layer (a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer A). The other adhesive layer is not particularly limited, and is, for example, a urethane adhesive, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyester adhesive, a polyamide adhesive, and an epoxy adhesive. , A pressure-sensitive adhesive layer formed from a known or commonly used pressure-sensitive adhesive such as a vinyl alkyl ether-based pressure-sensitive adhesive and a fluorine-based pressure-sensitive adhesive. The pressure-sensitive adhesive may be used alone or in combination of two or more.

Further, the photocurable pressure-sensitive adhesive sheet A is not limited to the pressure-sensitive adhesive layer A, the base material, and the other pressure-sensitive adhesive layer, but also other layers (for example, an intermediate layer, an undercoat layer, etc.) as long as the effects of the present invention are not impaired. May have.

The photocurable pressure-sensitive adhesive sheet A may be provided with a release film (separator) on the pressure-sensitive adhesive surface until it is used. The form in which the adhesive surface of the photocurable adhesive sheet A is protected by the release film is not particularly limited, but the form in which the respective adhesive surfaces are protected by the two release films may be used, or the adhesive surface may be rolled into a roll. By being rotated, one release film having both sides as release surfaces may be in a form in which each adhesive surface is protected. The release film is used as a protective material for the pressure-sensitive adhesive layer and is peeled off when it is attached to an adherend. In the photocurable pressure-sensitive adhesive sheet A, the release film also serves as a support for the pressure-sensitive adhesive layer. The release film does not necessarily have to be provided.

FIG. 1 is a diagram (cross-sectional view) schematically showing an embodiment of the photocurable pressure-sensitive adhesive sheet A of the present invention. In FIG. 1, 1A is a photocurable pressure-sensitive adhesive sheet of the present invention, 10 is a pressure-sensitive adhesive layer, and S1 and S2 are supports (including a separator).

The thickness (total thickness) of the photocurable pressure-sensitive adhesive sheet A is not particularly limited, but is preferably 10 μm to 1 mm, more preferably 100 to 500 μm, and even more preferably 150 to 350 μm. By setting the thickness to 10 μm or more, the adhesive layer A can easily follow the stepped portion, and the step absorbing property can be improved. The thickness of the photocurable pressure-sensitive adhesive sheet A does not include the thickness of the release film.

Since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it has light absorption with respect to visible light. The total light transmittance of the photocurable adhesive sheet A is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less or 5%. It may be as follows.

Since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it has excellent step absorption before curing. For example, in addition to a step of 5 to 10 μm, it is excellent in step absorption even for a high step exceeding 40 μm. Furthermore, it has step absorption even for high steps exceeding 80 μm.

Further, since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it has excellent processability after curing, and the adhesive chip is chipped during the cutting process, and the pressure-sensitive adhesive layer is squeezed out or sagging from the end portion during storage. Is suppressed.
Further, since the photocurable pressure-sensitive adhesive sheet A has the pressure-sensitive adhesive layer A, it is also excellent in adhesive reliability.

(Adhesive layer A)
The pressure-sensitive adhesive layer A is cured by irradiation with radiation. For example, when the photocurable pressure-sensitive adhesive sheet A is attached to the adherend and then the pressure-sensitive adhesive sheet is irradiated with radiation, the pressure-sensitive adhesive layer A is cured. The pressure-sensitive adhesive layer A before curing has high fluidity and excellent step absorption. For example, between the metal wiring layer of a self-luminous display device (mini / micro LED display device) and a light emitting element (LED chip). It is possible to seal minute steps without gaps. Further, the adhesive layer A after being cured by irradiation with radiation has improved workability, and the adhesive chipping during the cutting process and the protrusion and sagging of the adhesive layer from the end portion during storage are suppressed.

Examples of the radiation for curing include ionizing radiation such as α-rays, β-rays, γ-rays, X-rays, neutron rays, and electron beams, and ultraviolet rays. Ultraviolet rays are preferable because the pressure-sensitive adhesive layer A exhibits ultraviolet rays. Ultraviolet rays having a wavelength of 200 to 400 nm, more preferably 330 to 400 nm are more preferable. As the light source for irradiating ultraviolet rays, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave-excited lamp, a metal halide lamp, a chemical lamp, a black light, or an LED can be used. Further, the irradiation energy, irradiation time, and irradiation method of the radiation for curing can be appropriately set as long as the pressure-sensitive adhesive layer A can be cured and the adherend is not unduly affected. For example, when ultraviolet rays are used as the curing radiation, the irradiation amount (integrated light amount) is preferably 1000 mJ / cm ² to 10000 mJ / cm ² , more preferably 2000 mJ / cm ² to 4000 mJ / cm ² , and further. It is preferably 3000 mJ / cm ² .

(Storage modulus)
The storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer A before curing at 85 ° C. is not particularly limited, but is preferably less than 65 kPa, more preferably 60 kPa or less, still more preferably 55 kPa or less, and particularly preferably 50 kPa or less. Further, it may be 45 kPa or less. Such a configuration is preferable in order to realize excellent step absorption of the pressure-sensitive adhesive layer A before curing. Further, G'b85 is not particularly limited, but is preferably 5 kPa or more, more preferably 10 kPa or more, still more preferably 15 kPa or more, for example, from the viewpoint of handleability and workability. The storage elasticity (G'b85) of the pressure-sensitive adhesive layer A before curing at 85 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, first cross-linking agent); Mw, Tg of BP polymer; weight fraction of BP polymer; BP polymer and ethylenia-free It can be adjusted by the composition of the monomer component constituting the saturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The storage elastic modulus (G'a10) of the adhesive layer A after curing at 10 ° C. is not particularly limited, but is preferably, for example, preferably 90 kPa or more, more preferably 100 kPa or more, more preferably 110 kPa or more, and more preferably 120 kPa or more. , More preferably 130 kPa or more, more preferably larger than 146 kPa, more preferably 180 kPa or more, still more preferably 200 kPa or more, particularly preferably 250 kPa or more, further 300 kPa or more, or 350 kPa or more. Such a configuration is preferable in order to realize excellent processability of the pressure-sensitive adhesive layer A after curing. Further, G'a10 is not particularly limited, but is, for example, 5000 kPa or less, preferably 2500 kPa or less, and more preferably 1000 kPa or less from the viewpoint of adhesive reliability. The storage elasticity (G'a10) of the pressure-sensitive adhesive layer A after curing at 10 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, second cross-linking agent); Mw, Tg, BP equivalent of BP polymer (A); weight fraction of BP polymer; It can be adjusted by the composition of the monomer components constituting the BP polymer and the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The ratio of the storage elastic modulus (G'a10) of the adhesive layer A after curing to the storage elastic modulus (G'a10) at 85 ° C. of the adhesive layer A before curing (G'a10 / G'b85). Is not particularly limited, but is, for example, preferably larger than 3.3, more preferably 3.4 or more, still more preferably 3.5 or more, particularly preferably 3.6 or more, and further 3.7 or more. It may be 8 or more, 3.9 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, or 11 or more. Such a configuration is preferable in that both the excellent step absorption of the pressure-sensitive adhesive layer A before curing and the excellent processability of the pressure-sensitive adhesive layer A after curing can be achieved at the same time. The G'a10 / G'b85 is not particularly limited, but is preferably 100 or less, more preferably 50 or less, still more preferably 30 or less, for example, from the viewpoint of handleability, workability, and adhesive reliability. be. The ratio of the storage elasticity (G'a10) of the pressure-sensitive adhesive layer A after curing to the storage elasticity (G'a10) at 85 ° C. of the pressure-sensitive adhesive layer A before curing (G'a10 / G'b85). For example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight, amount used, monomer composition, type and amount of functional group of the base polymer described later; Types, amounts and proportions of the first and second cross-linking agents); Mw, Tg, BP equivalent of the BP polymer; weight fraction of the BP polymer; composition and functionality of the monomer components constituting the BP polymer and the ethylenically unsaturated compound. It can be adjusted by the type and amount of the group; the type and amount of the cross-linking agent) and the like.

The storage elastic modulus (G'b10) of the pressure-sensitive adhesive layer A before curing at 10 ° C. is not particularly limited, but is preferably, for example, preferably 10 kPa or more, more preferably 50 kPa or more, from the viewpoint of handleability and workability. More preferably, it may be 70 kPa or more, or 90 kPa or more, 100 kPa or more. Further, G'b10 is not particularly limited, but is, for example, 5000 kPa or less, preferably 2500 kPa or less, and more preferably 1000 kPa or less from the viewpoint of adhesive reliability. The storage elasticity (G'b10) of the pressure-sensitive adhesive layer A before curing at 10 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, first cross-linking agent); Mw, Tg of BP polymer; weight fraction of BP polymer; BP polymer and ethylenia-free It can be adjusted by the composition of the monomer component constituting the saturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The storage elastic modulus (G'a85) of the adhesive layer A after curing at 85 ° C. is not particularly limited, but is preferably, for example, preferably 10 kPa or more, preferably 20 kPa or more, from the viewpoint of handleability and workability. It is preferably 30 kPa or more. Further, G'a85 is not particularly limited, but is, for example, 1000 kPa or less, preferably 500 kPa or less, and more preferably 200 kPa or less from the viewpoint of adhesive reliability. The storage elasticity (G'a85) of the pressure-sensitive adhesive layer A after curing at 85 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, second cross-linking agent); Mw, Tg, BP equivalent of BP polymer; weight fraction of BP polymer; BP polymer and It can be adjusted by the composition of the monomer component constituting the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The storage elastic modulus (G'a25) of the adhesive layer A after curing at 25 ° C. is not particularly limited, but is preferably, for example, preferably 70 kPa or more, more preferably larger than 100 kPa, more preferably 150 kPa or more, still more preferably 170 kPa. That is all. Such a configuration is preferable in order to realize excellent processability of the pressure-sensitive adhesive layer A after curing. The G'a25 is not particularly limited, but is, for example, 5000 kPa or less, preferably 2500 kPa or less, and more preferably 1000 kPa or less from the viewpoint of adhesive reliability. The storage elasticity (G'a25) of the pressure-sensitive adhesive layer A after curing at 25 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, second cross-linking agent); Mw, Tg, BP equivalent of BP polymer; weight fraction of BP polymer; BP polymer and It can be adjusted by the composition of the monomer component constituting the ethylenically unsaturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The storage elastic modulus (G'b25) of the pressure-sensitive adhesive layer A before curing at 25 ° C. is not particularly limited, but is, for example, 300 kPa or less, preferably 250 kPa or less, and more preferably 200 kPa or less. Such a configuration is preferable in order to realize excellent step absorption of the pressure-sensitive adhesive layer A before curing. The G'b25 is not particularly limited, but is, for example, 10 kPa or more, preferably 30 kPa or more, and more preferably 50 kPa or more from the viewpoint of adhesive reliability. The storage elasticity (G'b25) of the pressure-sensitive adhesive layer A before curing at 25 ° C. is, for example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight of the base polymer described below). , Amount used, monomer composition, type and amount of functional group; type and amount of cross-linking agent (particularly, first cross-linking agent); Mw, Tg of BP polymer; weight fraction of BP polymer; BP polymer and ethylenia-free It can be adjusted by the composition of the monomer component constituting the saturated compound, the type and amount of the functional group; the type and amount of the cross-linking agent) and the like.

The ratio of the storage elastic modulus (G'a25) of the adhesive layer A after curing to the storage elastic modulus (G'a25) at 85 ° C. of the adhesive layer A before curing (G'a25 / G'b85). Is not particularly limited, but is, for example, preferably 0.3 or more, more preferably 0.5 or more, more preferably 1 or more, more preferably larger than 3, preferably 3.5 or more, and more preferably 4 or more. be. Such a configuration is preferable in that both the excellent step absorption of the pressure-sensitive adhesive layer A before curing and the excellent processability of the pressure-sensitive adhesive layer A after curing can be achieved at the same time. The G'a25 / G'b85 is not particularly limited, but is, for example, 100 or less, preferably 50 or less, and more preferably 30 or less from the viewpoint of handleability, workability, and adhesive reliability. The ratio of the storage elasticity (G'a25) of the pressure-sensitive adhesive layer A after curing to the storage elasticity (G'a25) at 85 ° C. of the pressure-sensitive adhesive layer A before curing (G'a25 / G'b85). For example, the composition of the hybrid pressure-sensitive adhesive composition described below for forming the pressure-sensitive adhesive layer A (for example, the molecular weight, amount used, monomer composition, type and amount of functional group of the base polymer described later; Types, amounts and proportions of the first and second cross-linking agents); Mw, Tg, BP equivalent of the BP polymer; weight fraction of the BP polymer; composition and functionality of the monomer components constituting the BP polymer and the ethylenically unsaturated compound. It can be adjusted by the type and amount of the group; the type and amount of the cross-linking agent) and the like.

The curing conditions in the above-mentioned "adhesive layer A after curing" are not particularly limited, but ultraviolet rays in which the adhesive layer A exhibits transparency are preferable. Ultraviolet rays having a wavelength of 200 to 400 nm, more preferably 330 to 400 nm are more preferable. As the light source for irradiating ultraviolet rays, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave-excited lamp, a metal halide lamp, a chemical lamp, a black light, or an LED can be used. Further, the irradiation energy, irradiation time, and irradiation method of the radiation for curing can be appropriately set as long as the pressure-sensitive adhesive layer A can be cured and the adherend is not unduly affected. For example, when ultraviolet rays are used as the curing radiation, the irradiation amount (integrated light amount) is preferably 1000 mJ / cm ² to 10000 mJ / cm ² , more preferably 2000 mJ / cm ² to 4000 mJ / cm ² , and further. It is preferably 3000 mJ / cm ² .
Further, the storage elastic modulus is measured by dynamic viscoelasticity measurement.

(Other properties of adhesive layer A)
The gel fraction of the pressure-sensitive adhesive layer A before curing is 50 to 90% by weight, preferably 50 to 80% by weight, and more preferably 50 to 70% by weight. By setting the gel fraction to 90% by weight or less, the cohesive force of the pressure-sensitive adhesive layer A becomes small to some extent and the pressure-sensitive adhesive layer A becomes soft, so that the pressure-sensitive adhesive layer easily follows the stepped portion, which is an excellent step. Absorbency is obtained. On the other hand, by setting the gel fraction to 50% by weight or more, it is possible to suppress the occurrence of the problem that the pressure-sensitive adhesive layer becomes too soft and the handleability and workability of the pressure-sensitive adhesive sheet deteriorate, and also in a high temperature environment. In a high temperature and high humidity environment, it is possible to suppress the generation of bubbles and floats and improve the adhesive reliability. The gel fraction can be controlled, for example, by the type and content (usage amount) of the cross-linking agent.

The gel fraction (ratio of solvent insoluble matter) can be determined as ethyl acetate insoluble matter. Specifically, the pressure-sensitive adhesive layer is determined as a weight fraction (unit: weight%) of the insoluble component after being immersed in ethyl acetate at room temperature (23 ° C.) for 7 days before immersion. More specifically, the gel fraction is a value calculated by the following "method for measuring gel fraction".
(Measuring method of gel fraction)
Approximately 1 g of the pressure-sensitive adhesive layer is collected, the weight thereof is measured, and the weight is referred to as "the weight of the pressure-sensitive adhesive layer before immersion". Next, after immersing the collected pressure-sensitive adhesive layer in 40 g of ethyl acetate for 7 days, all the components (insoluble portions) insoluble in ethyl acetate were recovered, and all the recovered insoluble portions were dried at 130 ° C. for 2 hours. After removing the ethyl acetate, the weight thereof is measured and used as the "dry weight of the insoluble portion" (weight of the pressure-sensitive adhesive layer after immersion). Then, the obtained numerical value is substituted into the following formula for calculation.
Gel fraction (% by weight) = [(dry weight of insoluble portion) / (weight of adhesive layer before immersion)] x 100
The gel fraction of the pressure-sensitive adhesive layer A before curing is, for example, the composition of the hybrid pressure-sensitive adhesive composition described later for forming the pressure-sensitive adhesive layer A (for example, the molecular weight, the amount used, the monomer composition, and the functionality of the base polymer described later). Type and amount of group; Type and amount of cross-linking agent (particularly, first cross-linking agent); Mw, Tg of BP polymer (A); Weight fraction of BP polymer; Constituting BP polymer and ethylenically unsaturated compound It can be adjusted by the composition of the monomer component, the type and amount of the functional group; the type and amount of the cross-linking agent), the curing conditions (heating conditions, irradiation conditions) and the like.

The glass transition point (Tg) of the pressure-sensitive adhesive layer A before curing is not particularly limited, but is preferably -60 to 20 ° C, more preferably -40 to 10 ° C, and even more preferably -40 to 10 ° C. It is -30 to 0 ° C. If the Tg is higher than 20 ° C, the adhesive strength cannot be exhibited at room temperature.

The Tg is not particularly limited, but can be measured according to JIS K 7121 by differential scanning calorimetry (DSC), for example, using the pressure-sensitive adhesive layer as a measurement sample. Specifically, for example, as a measuring device, a device name "Q-2000" manufactured by TA instruments can be used, and measurement can be performed from −80 ° C. to 80 ° C. under the condition of a heating rate of 10 ° C./min.

The thickness of the pressure-sensitive adhesive layer A is not particularly limited, and may be appropriately set so that the light emitting elements arranged on the display panel described later can be sufficiently sealed. For example, the thickness of the pressure-sensitive adhesive layer A is 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.5 times, and further the height of the light emitting element. It is preferably adjusted to be 1.3 to 2.0 times. By increasing the thickness to 1.0 times or more, the adhesive layer A can easily follow the step, and the step absorption property is improved. Further, by setting the thickness to 4.0 or less, the pressure-sensitive adhesive layer A is less likely to be deformed, and the workability is improved.

The thickness of the pressure-sensitive adhesive layer A is, for example, about 10 to 500 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. The thickness of the pressure-sensitive adhesive layer A may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. By setting the thickness to 10 μm or more, the adhesive layer A can easily follow the step portion, and the step absorption property is improved. Further, by setting the thickness to 500 μm or less, the pressure-sensitive adhesive layer A is less likely to be deformed, and the workability is improved.

In the pressure-sensitive adhesive layer A, the maximum value of the transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm.

The pressure-sensitive adhesive layer A has lower transparency to visible light (wavelength 400 to 700 nm) than in the ultraviolet region (wavelength 200 to 400 nm, preferably wavelength 330 to 400 nm). The adhesive layer A, which has excellent light-shielding property against visible light, seals a minute step between the metal wiring layer of the self-luminous display device (mini / micro LED display device) and the light-emitting element (LED chip) without gaps. , Reflection due to metal wiring and the like is prevented, color mixing of the light emitting element (LED chip) is prevented, and the contrast of the image is improved.

On the other hand, since the pressure-sensitive adhesive layer A has a higher transmittance in the ultraviolet region (wavelength 200 to 400 nm, preferably wavelength 330 to 400 nm) than visible light, it can be cured by irradiating with ultraviolet light. The pressure-sensitive adhesive layer A cured by irradiation with ultraviolet rays has improved workability, and suppresses adhesive chipping during cutting and protrusion and sagging of the pressure-sensitive adhesive layer from the edges during storage.

As used herein, the "maximum value of transmittance at a wavelength of 200 to 400 nm" means the highest transmittance in the range of a wavelength of 200 to 400 nm. For example, when there is one maximum value of transmittance in the region of wavelength 200 to 400 nm, the maximum value is the maximum value of transmittance. When there is no maximum value of the transmittance in the region of the wavelength of 200 to 400 nm, the higher of the transmittance of the wavelength of 200 nm or 400 nm is the maximum value. The same applies to the "maximum value of the transmittance at a wavelength of 330 to 400 nm" and the "maximum value of the transmittance at a wavelength of 400 to 700 nm".

The maximum value of the transmittance of the pressure-sensitive adhesive layer A at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20. It may be% or less or 10% or less.

Further, it is preferable that the pressure-sensitive adhesive layer A has an average transmittance of a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) larger than an average transmittance of a wavelength of 400 to 700 nm. The average transmittance of the pressure-sensitive adhesive layer A at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less. Alternatively, it may be 10% or less.

Since the pressure-sensitive adhesive layer A exhibits excellent light-shielding property against visible light, it is possible to prevent reflection and gloss of the metal surface even when the metal adherend is laminated on the pressure-sensitive adhesive layer A. The reflectance in the visible light region of 5 ° specular reflection when the metal adherend is laminated on the pressure-sensitive adhesive layer A is preferably 50% or less, more preferably 30% or less, and 15% or less. Is more preferable, and 10% or less is particularly preferable. The glossiness (based on JIS Z 8741-1997) when the metal adherend is laminated on the pressure-sensitive adhesive layer A is preferably 100% or less, more preferably 80% or less, and more preferably 60% or less. It is more preferably present, and particularly preferably 50% or less.
As the metal adherend, copper, aluminum, stainless steel, or the like can be used.

(Colorant)
The pressure-sensitive adhesive layer A contains a colorant. As the colorant, the colorant having a maximum transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm (hereinafter referred to as “colorant A”). It may be referred to).

The structure in which the pressure-sensitive adhesive layer A has a maximum transmittance at a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) is larger than a maximum value of a transmittance at a wavelength of 400 to 700 nm is not particularly limited, but is preferable. It can be realized by including the colorant A.

The maximum value of the transmittance of the colorant (including the colorant A) at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less. , 30% or less, 20% or less, 10% or less, or 5% or less.

Further, the colorant (including the colorant A) preferably has an average transmittance of a wavelength of 200 to 400 nm (preferably a wavelength of 330 to 400 nm) larger than the average transmittance of a wavelength of 400 to 700 nm. The average transmittance of the colorant (including the colorant A) at a wavelength of 400 to 700 nm (visible light region) is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30. % Or less, 20% or less, 10% or less, or 5% or less.

The transmittance of the colorant (including the colorant A) is an appropriate solvent or dispersion medium (wavelength 200 to 700 nm) such as tetrahydrofuran (THF) so that the transmittance at a wavelength of 400 nm is about 50 to 60%. It can be measured using a solution or dispersion diluted with an organic solvent with low absorption).

The colorant (including the colorant A) may be a dye or a pigment as long as it can be dissolved or dispersed in the pressure-sensitive adhesive layer A. Dyes are preferable because low haze can be achieved even with a small amount of addition, and unlike pigments, they do not have sedimentation properties and can be easily distributed uniformly. In addition, pigments are also preferable because they have high color expression even when added in a small amount. When a pigment is used as a colorant, it preferably has low or no conductivity. When a dye is used, it is preferably used in combination with an antioxidant or the like.

Examples of the ultraviolet-transparent black pigment include "9500BLACK", "9256BLACK", "9170BLACK", "UVBK-0001" manufactured by Tokushiki, and "UB-1" manufactured by Mitsubishi Materials Electronics Co., Ltd. Examples of the ultraviolet-transparent black dye include "SOC-L-0123" manufactured by Orient Chemical Industries.

The content of the colorant (including the colorant A) in the pressure-sensitive adhesive layer A is, for example, about 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive layer A. Yes, it may be appropriately set according to the type of the colorant, the color tone of the pressure-sensitive adhesive layer A, the light transmittance, and the like. The colorant may be added as a solution or dispersion dissolved or dispersed in an appropriate solvent.

(Hybrid adhesive composition)
The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer A is not particularly limited as long as it satisfies the above-mentioned properties (a) to (d), but preferably contains a colorant (preferably colorant A). A hybrid pressure-sensitive adhesive composition is preferred.

The hybrid pressure-sensitive adhesive contains two types of polymerization initiators and cross-linking agents having different curing initiation conditions such as heat and light, or a cross-linking functional group (in the present specification, the polymerization initiator, the cross-linking agent, and a cross-linking agent). A pressure-sensitive adhesive that cures stepwise by having a sex functional group (sometimes referred to as a "trigger").

In the hybrid pressure-sensitive adhesive, first, one of the triggers (sometimes referred to as "first trigger" in the present specification) has high fluidity and is in a semi-cured state having excellent step absorption, which is sufficient for the step. After that, the curing can be completed by the other trigger (sometimes referred to as a "second trigger" in the present specification) by irradiating with light, and the workability can be improved.

The hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A is not particularly limited, but typically contains a base polymer, a cross-linking agent, and a photopolymerization initiator. Here, the base polymer is a polymer cured by the above-mentioned first trigger, and the cross-linking agent and the photopolymerization initiator correspond to the second trigger.

The base polymer is not particularly limited as long as it is a sticky material that can be used for optical applications. For example, an acrylic polymer contained as a base polymer in an acrylic pressure-sensitive adhesive layer, a rubber-based polymer contained in a rubber-based pressure-sensitive adhesive layer (natural rubber-based pressure-sensitive adhesive layer, synthetic rubber-based pressure-sensitive adhesive layer, etc.) as a base polymer, and a silicone-based polymer. Silicone-based polymer contained as a base polymer in the pressure-sensitive adhesive layer, polyester-based polymer contained in a polyester-based pressure-sensitive adhesive layer as a base polymer, urethane-based polymer contained in a urethane-based pressure-sensitive adhesive layer as a base polymer, and polyamide-based pressure-sensitive adhesive layer as a base. Polyamide-based polymer contained as a polymer, epoxy-based polymer contained as an epoxy-based pressure-sensitive adhesive layer as a base polymer, vinyl-alkyl ether-based polymer contained as a base polymer in a vinyl alkyl ether-based pressure-sensitive adhesive layer, and fluorine-based pressure-sensitive adhesive layer as a base polymer. It can be appropriately selected and used from the fluoropolymers contained in the above, and any one of these polymers can be used alone or in combination of two or more. From the viewpoint of processability and durability, it is preferable to use an acrylic polymer. The acrylic polymer is not particularly limited, but is preferably a homopolymer or a copolymer of a monomer containing a (meth) acrylic acid alkyl ester as a main component. Here, the expression "(meth) acrylic" is used to mean one or both of "acrylic" and "methacrylic", and the same applies to other cases. In the present invention, the term acrylic polymer is used in the sense that in addition to the above-mentioned (meth) acrylic acid alkyl ester, other monomers copolymerizable therewith are also included.

The acrylic polymer is preferably a monomer derived from an acrylic acid alkyl ester having a linear or branched alkyl group and / or a methacrylic acid alkyl ester having a linear or branched alkyl group. The unit is included as the main monomer unit with the highest weight ratio.

A (meth) acrylic acid alkyl ester having a linear or branched alkyl group for forming a monomer unit of the acrylic polymer, that is, a straight chain contained in a monomer component for forming the acrylic polymer. Examples of the (meth) acrylic acid alkyl ester having a state or branched alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and isopropyl (meth) acrylate. N-butyl (meth) acrylate, s-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, (meth) ) Hexyl acrylate, (meth) heptyl acrylate, (meth) octyl acrylate, (meth) 2-ethylhexyl acrylate, (meth) isooctyl acrylate, (meth) nonyl acrylate, (meth) isononyl acrylate, ( Decyl Acrylic Acid, (Meta) Isodecyl Acrylate, (Meta) Undecyl Acrylate, (Meta) Dodecyl Acrylate, (Meta) Tridecyl Acrylate, (Meta) Tetradecyl Acrylic Acid, (Meta) Pentadecyl Acrylate, (Meta) ) Hexadecyl acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecil (meth) acrylate, and eicocil (meth) acrylate, which have 1 to 20 carbon atoms. Examples thereof include (meth) acrylic acid alkyl esters having linear or branched alkyl groups. As the (meth) acrylic acid alkyl ester for the acrylic polymer, one kind of (meth) acrylic acid alkyl ester may be used, or two or more kinds of (meth) acrylic acid alkyl esters may be used. .. In the present embodiment, the (meth) acrylic acid alkyl ester for an acrylic polymer is preferably at least one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, and isostearyl acrylate. Is used.

The proportion of the monomer unit derived from the (meth) acrylic acid alkyl ester having a linear or branched alkyl group in the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more, and more preferably. Is 70% by weight or more, more preferably 80% by weight or more, and more preferably 90% by weight or more. That is, the ratio of the (meth) acrylic acid alkyl ester in the monomer component composition of the raw material for forming the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more, and more preferably 70% by weight or more. , More preferably 80% by weight or more, more preferably 90% by weight or more.

The acrylic polymer may contain a monomer unit derived from an alicyclic monomer. Examples of the alicyclic monomer for forming the monomer unit of the acrylic polymer, that is, the alicyclic monomer contained in the monomer component for forming the acrylic polymer, include (meth) acrylic acid cycloalkyl ester. Examples thereof include a (meth) acrylic acid ester having a cyclic hydrocarbon ring and a (meth) acrylic acid ester having three or more hydrocarbon rings. Examples of the (meth) acrylic acid cycloalkyl ester include (meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid cycloheptyl, and (meth) acrylic acid cyclooctyl. Examples of the (meth) acrylic acid ester having a bicyclic hydrocarbon ring include (meth) acrylate Bornyl and (meth) acrylate isobornyl. Examples of the (meth) acrylic acid ester having three or more hydrocarbon rings include (meth) acrylate dicyclopentanyl, (meth) acrylate dicyclopentanyloxyethyl, and (meth) acrylate tricyclopentan. Nyl, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate can be mentioned. As the alicyclic monomer for the acrylic polymer, one kind of alicyclic monomer may be used, or two or more kinds of alicyclic monomers may be used. In the present embodiment, as the alicyclic monomer for the acrylic polymer, at least one selected from the group consisting of cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, and isobornyl methacrylate is preferably used.

The proportion of the monomer unit derived from the alicyclic monomer in the acrylic polymer is preferably 5 to 60% by weight from the viewpoint of realizing appropriate flexibility in the base polymer formed containing the acrylic polymer. It is more preferably 10 to 50% by weight, more preferably 12 to 40% by weight. Further, in some embodiments of the present invention, the acrylic polymer does not have to contain a monomer unit derived from an alicyclic monomer.

The acrylic polymer may contain a monomer unit derived from a hydroxyl group-containing monomer. The hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the acrylic polymer in the base polymer contains a hydroxyl group-containing monomer unit, it is easy to obtain adhesiveness and appropriate cohesive force in the base polymer. In addition, the hydroxyl group can also serve as a reaction point with a cross-linking agent described later.

Examples of the hydroxyl group-containing monomer for forming the monomer unit of the acrylic polymer, that is, the hydroxyl group-containing monomer contained in the monomer component for forming the acrylic polymer, include a hydroxyl group-containing (meth) acrylic acid ester and vinyl alcohol. , And allyl alcohol. Examples of the hydroxyl group-containing (meth) acrylic acid ester include (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 3-hydroxypropyl, and (meth) acrylic acid 4-. Hydroxybutyl, (meth) acrylate 6-hydroxyhexyl, (meth) acrylate hydroxyoctyl, (meth) acrylate hydroxydecyl, (meth) acrylate hydroxylauryl, and (meth) acrylate (4-hydroxymethylcyclohexyl) Methyl is mentioned. As the hydroxyl group-containing monomer for the acrylic polymer, one kind of hydroxyl group-containing monomer may be used, or two or more kinds of hydroxyl group-containing monomers may be used. In the present embodiment, as the hydroxyl group-containing monomer for the acrylic polymer, preferably 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4 acrylate. -At least one selected from the group consisting of hydroxybutyl and 4-hydroxybutyl methacrylate is used.

The proportion of the monomer unit derived from the hydroxyl group-containing monomer in the acrylic polymer is preferably 1% by weight or more, more preferably 2% by weight or more, more preferably 3% by weight or more, still more preferably 7% by weight or more, and more preferably. Is 10% by weight or more, more preferably 15% by weight or more. The proportion of the monomer unit derived from the hydroxyl group-containing monomer in the acrylic polymer is preferably 35% by weight or less, more preferably 30% by weight or less. These configurations regarding the ratio of the hydroxyl group-containing monomer are suitable for realizing adhesiveness and appropriate cohesive force in the base polymer formed by containing the acrylic polymer.

The acrylic polymer may contain a monomer unit derived from a nitrogen atom-containing monomer. A nitrogen atom-containing monomer is a monomer having at least one nitrogen atom in a monomer unit. When the acrylic polymer in the base polymer contains a nitrogen atom-containing monomer unit, it is easy to obtain hardness and good adhesive reliability in the base polymer.

Examples of the nitrogen atom-containing monomer for forming the monomer unit of the acrylic polymer, that is, the nitrogen atom-containing monomer contained in the monomer component for forming the acrylic polymer, include N-vinyl cyclic amide and (meth). Examples include acrylamides.

で表わされるＮ－ビニル環状アミドを用いることができる。ここで、一般式（１）中、Ｒ¹は２価の有機基であり、具体的には－（ＣＨ₂）_n－である。ｎは２～７（好ましくは２，３または４）の整数である。 As the N-vinyl cyclic amide which is a nitrogen atom-containing monomer, for example, the general formula (1):

The N-vinyl cyclic amide represented by is used. Here, in the general formula (1), R ¹ is a divalent organic group, specifically − (CH ₂ ) _n −. n is an integer of 2 to 7 (preferably 2, 3 or 4).

Examples of the N-vinyl cyclic amide include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, and N-vinyl-1,3-oxazine. -2-one and N-vinyl-3,5-morpholindione can be mentioned.

Examples of (meth) acrylamides as nitrogen atom-containing monomers include (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nn-butyl (meth) acrylamide, and N-octyl ( Examples include meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, and N, N-diisopropyl (meth) acrylamide. As the nitrogen atom-containing monomer for the acrylic polymer, one kind of nitrogen atom-containing monomer may be used, or two or more kinds of nitrogen atom-containing monomers may be used. In this embodiment, N-vinyl-2-pyrrolidone is preferably used as the nitrogen atom-containing monomer for the acrylic polymer.

The ratio of the monomer unit derived from the nitrogen atom-containing monomer in the acrylic polymer is preferably 1 weight from the viewpoint of realizing appropriate hardness and adhesiveness in the base polymer formed containing the acrylic polymer. % Or more, more preferably 3% by weight or more, more preferably 5% by weight or more. Further, the ratio of the monomer unit derived from the nitrogen atom-containing monomer in the acrylic polymer suppresses the base polymer formed containing the acrylic polymer from becoming too hard, and realizes good adhesive reliability. From this point of view, it is preferably 30% by weight or less, more preferably 25% by weight or less. Further, in some embodiments of the present invention, the acrylic polymer may not contain a monomer unit derived from a nitrogen atom-containing monomer.

The acrylic polymer may contain a monomer unit derived from a carboxy group-containing monomer. The carboxy group-containing monomer is a monomer having at least one carboxy group in the monomer unit. When the acrylic polymer in the base polymer contains a carboxy group-containing monomer unit, good adhesion reliability may be obtained in the base polymer. The carboxy group can also serve as a reaction point with a cross-linking agent described later.

Examples of the carboxy group-containing monomer for forming the monomer unit of the acrylic polymer, that is, the carboxy group-containing monomer contained in the monomer component for forming the acrylic polymer include (meth) acrylic acid and itaconic acid. Examples include maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. As the carboxy group-containing monomer for the acrylic polymer, one kind of carboxy group-containing monomer may be used, or two or more kinds of carboxy group-containing monomers may be used. In this embodiment, acrylic acid is preferably used as the carboxy group-containing monomer for the acrylic polymer.

The ratio of the monomer unit derived from the carboxy group-containing monomer in the acrylic polymer is the polar group and the carboxy group when the polar group is present on the surface of the adherend in the base polymer formed by containing the acrylic polymer. From the viewpoint of obtaining the contribution of the above-mentioned interaction and ensuring good adhesion reliability, it is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. Further, the proportion of the monomer unit derived from the carboxy group-containing monomer in the acrylic polymer suppresses the base polymer formed containing the acrylic polymer from becoming too hard, and realizes good adhesive reliability. From the viewpoint, it is preferably 20% by weight or less, more preferably 15% by weight or less. Further, the acrylic polymer may not substantially contain a carboxy group-containing monomer as a constituent monomer unit from the viewpoint of metal corrosion prevention and the like. The fact that the carboxy group-containing monomer is substantially not contained means that the carboxy group-containing monomer is not intentionally used, and is preferably 0.05% by weight or less (for example, 0 to 0.05% by weight). What is preferably 0.01% by weight or less (for example, 0 to 0.01% by weight), more preferably 0.001% by weight or less (for example, 0 to 0.001% by weight) is substantially not contained. It can be said.

The acrylic polymer may be a partial polymer of a mixture of monomer components constituting the acrylic polymer. Further, the acrylic polymer may be a partial polymer of a mixture of some monomer components constituting the acrylic polymer with the remaining monomer components added. The above-mentioned "partial polymer of a mixture of monomer components" means a composition in which one or more of the constituent monomer components are partially polymerized.

The base polymer may contain a cross-linking agent. When the base polymer has a crosslinked structure due to the crosslinking agent, the viscosity is increased, the shape stability is improved, and the pressure-sensitive adhesive layer A is easily formed. Examples of the cross-linking agent include a polyfunctional (meth) acrylate which is a copolymerized cross-linking agent (photocurable cross-linking agent) of an acrylic polymer and a thermosetting cross-linking agent. The base polymer may have a crosslinked structure derived only from the polyfunctional (meth) acrylate, or may have a crosslinked structure derived only from the thermosetting crosslinker, and may have a crosslinked structure derived only from the thermosetting (meth) acrylate. And may have a cross-linking structure derived from both the thermosetting cross-linking agent.
This cross-linking agent is a cross-linking agent (first cross-linking agent) that constitutes a first trigger when the pressure-sensitive adhesive layer A of the present invention is composed of a hybrid pressure-sensitive adhesive composition. That is, the base polymer having a crosslinked structure derived from the first crosslinking agent is in a semi-cured state with high fluidity and exhibits excellent step absorption.

Examples of the polyfunctional (meth) acrylate as a copolymerizable cross-linking agent (photocurable cross-linking agent) include 1,6-hexanediol di (meth) acrylate, butanediol di (meth) acrylate, and (poly) ethylene glycol di. (Meta) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Examples thereof include trimethylol propanetri (meth) acrylate, tetramethylol methanetri (meth) acrylate, allyl (meth) acrylate, and vinyl (meth) acrylate. As the polyfunctional (meth) acrylate for the acrylic polymer, one kind of polyfunctional (meth) acrylate may be used, or two or more kinds of polyfunctional (meth) acrylate may be used. In this embodiment, the polyfunctional (meth) acrylate for the acrylic polymer preferably comprises 1,6-hexanediol diacrylate, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, and polypropylene glycol diacrylate. At least one selected from the group is used.

The proportion of the monomer unit derived from the polyfunctional (meth) acrylate in the acrylic polymer is preferably 0.005% by weight or more, more preferably 0.01% by weight or more, more preferably 0.03% by weight or more, and more. It is preferably 0.05% by weight or more. The proportion of the monomer unit derived from the polyfunctional (meth) acrylate in the acrylic polymer is preferably 1% by weight or less, more preferably 0.5% by weight or less. These configurations regarding the proportion of the polyfunctional (meth) acrylate are suitable for realizing appropriate hardness, adhesiveness, shape stability, and excellent step absorption in the base polymer formed by containing the acrylic polymer. ..

Examples of the thermosetting cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, metal chelate-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, metal alkoxide-based cross-linking agents, and metals. Examples thereof include a salt-based cross-linking agent, a carbodiimide-based cross-linking agent, an oxazoline-based cross-linking agent, an aziridine-based cross-linking agent, and an amine-based cross-linking agent. The base polymer may contain one type of the thermosetting cross-linking agent, or may contain two or more types of the thermosetting cross-linking agent. Preferably, at least one selected from the group consisting of an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent is used.

Examples of the isocyanate-based cross-linking agent include lower aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. Examples of the lower aliphatic polyisocyanates include 1,2-ethylene diisocyanate, 1,4-butylenediocyanate, and 1,6-hexamethylene diisocyanate. Examples of the alicyclic polyisocyanate include cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylene diisocyanate. Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate. The isocyanate-based cross-linking agents include trimethylolpropane / tolylene diisocyanate adduct (trade name "Coronate L", manufactured by Nippon Polyurethane Industry Co., Ltd.) and trimethylolpropane / hexamethylene diisocyanate adduct (trade name "Coronate HL"). , Nippon Polyurethane Industry Co., Ltd.), and trimethylolpropane / xylylene diisocyanate adduct (trade name "Takenate D-110N", manufactured by Mitsui Chemicals Co., Ltd.) and the like.

Examples of the epoxy-based cross-linking agent (polyfunctional epoxy compound) include N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, and 1,3-bis (N, N-diglycidylamino). Methyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2- Hydroxyethyl) isocyanurate, resorcin diglycidyl ether, and bisphenol-S-diglycidyl ether. Moreover, as an epoxy-based cross-linking agent, an epoxy-based resin having two or more epoxy groups can also be mentioned. In addition, examples of the epoxy-based cross-linking agent include commercially available products such as the trade name "Tetrad C" (manufactured by Mitsubishi Gas Chemical Company, Inc.).

When the above thermosetting cross-linking agent for cross-linking between the base polymers is contained, the content of the thermosetting cross-linking agent in the base polymer improves the shape stability of the base polymer and the pressure-sensitive adhesive layer. From the viewpoint of facilitating the formation of A, sufficient adhesive reliability to the adherend, and achieving excellent step absorption, preferably 0.001 part by weight with respect to 100 parts by weight of the total amount of the monomer components constituting the base polymer. The above is more preferably 0.01 parts by weight or more. Further, the content of the thermosetting cross-linking agent is 100, which is the total amount of the monomer components constituting the base polymer, from the viewpoint of exhibiting appropriate flexibility in the base polymer and realizing good adhesive strength and excellent step absorption. It is preferably 10 parts by weight or less, more preferably 5 parts by weight or less with respect to parts by weight.

When the base polymer contains the above acrylic polymer as a pressure-sensitive adhesive, the content of the acrylic polymer in the base polymer is, for example, 85 to 100% by weight.

The base polymer may contain a polymerization initiator in addition to the monomer and the cross-linking agent for forming the acrylic polymer. Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator. The base polymer may contain one kind of polymerization initiator or two or more kinds of polymerization initiators.
The polymerization initiator is a polymerization initiator (first polymerization initiator) that constitutes a first trigger when the pressure-sensitive adhesive layer A of the present invention is formed of the hybrid pressure-sensitive adhesive composition.

Examples of the photopolymerization initiator include a benzoin ether-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, and a photoactive oxime-based photopolymerization. Examples thereof include an initiator, a benzoin-based photopolymerization initiator, a benzyl-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a ketal-based photopolymerization initiator, and a thioxanthone-based photopolymerization initiator. Examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethan-1-one. Can be mentioned. Examples of the acetophenone-based photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). ) Dichloroacetophenone can be mentioned. Examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one. .. Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalene sulfonyl chloride. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin-based photopolymerization initiator include benzoin. Examples of the benzyl-based photopolymerization initiator include benzyl. Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and polyvinylbenzophenone. Examples of the ketal-based photopolymerization initiator include benzyldimethyl ketal. Examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

The amount of the photopolymerization initiator used is not particularly limited, but is preferably 0.001 to 1 part by weight with respect to 100 parts by weight of the total monomer unit of the acrylic polymer (total amount of the monomer components constituting the acrylic polymer). , More preferably 0.01 to 0.50 parts by weight.

Examples of the thermal polymerization initiator include an azo-based polymerization initiator, a peroxide-based polymerization initiator, a redox-based polymerization initiator, and the like. Examples of the azo-based polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile (AMBN), and 2,2'-azobis (2). -Methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovalerian acid, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2,4) -Dimethylvaleronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4,4-trimethylpentane) and the like. Examples of the peroxide-based polymerization initiator include benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, and 1,1-bis (t). -Butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclododecane and the like can be mentioned.

The amount of the thermal polymerization initiator used is not particularly limited, but is, for example, 0.05 to 0.5 weight with respect to 100 parts by weight of all the monomer units of the acrylic polymer (the total amount of the monomer components constituting the acrylic polymer). The amount is preferably 0.1 to 0.3 parts by weight.

Examples of the cross-linking agent contained in the hybrid pressure-sensitive adhesive composition composed of the pressure-sensitive adhesive layer A include polyfunctional (meth) acrylates, which are the above-mentioned copolymerizable cross-linking agents (photocurable cross-linking agents). The cross-linking agent is a cross-linking agent (second cross-linking agent) that constitutes a second trigger when the pressure-sensitive adhesive layer A of the present invention is composed of a hybrid pressure-sensitive adhesive composition. That is, the base polymer cured by the second cross-linking agent exhibits excellent processability.

The content of the polyfunctional (meth) acrylate as the second cross-linking agent is not particularly limited, but is preferably 0. It is 1 part by weight or more, more preferably 1 part by weight or more, more preferably 2 parts by weight or more, and more preferably 4 parts by weight or more. The content of the polyfunctional (meth) acrylate is preferably 60 parts by weight or less, more preferably 40 parts by weight or less, based on 100 parts by weight of the base polymer. These configurations regarding the content of the polyfunctional (meth) acrylate as the second cross-linking agent are suitable for realizing excellent processability by curing the base polymer formed by containing the acrylic polymer. ..

Examples of the photopolymerization initiator contained in the hybrid pressure-sensitive adhesive composition composed of the pressure-sensitive adhesive layer A include the same photopolymerization initiators as described above. The photopolymerization initiator is a polymerization initiator (second polymerization initiator) that constitutes a second trigger when the pressure-sensitive adhesive layer A of the present invention is composed of a hybrid pressure-sensitive adhesive composition. That is, the base polymer cured by the photopolymerization initiator, which is the second polymerization initiator, exhibits excellent processability.

The content of the photopolymerization initiator, which is the second polymerization initiator, is not particularly limited, but is 0 to 2 parts by weight with respect to 100 parts by weight of the base polymer from the viewpoint of imparting excellent processability to the cured base polymer. Is preferable, and more preferably 0.005 to 1.5 parts by weight. These configurations regarding the content of the photopolymerization initiator as the second polymerization initiator are suitable for realizing excellent processability by curing the base polymer formed by containing the acrylic polymer.

The hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A may be, if necessary, an ultraviolet absorber, a rust preventive agent, an antistatic agent, a cross-linking accelerator, a silane coupling agent, a tackifier resin, an antiaging agent, and a filler. , Antioxidants, chain transfer agents, plasticizers, softeners, surfactants, polyols, solvents and other additives may be further contained. Examples of the tackifier resin include rosin derivatives, polyterpene resins, petroleum resins, and oil-soluble phenols.

The hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A may contain a silane coupling agent as long as the effects of the present invention are not impaired. When the pressure-sensitive adhesive layer A contains a silane coupling agent, the adhesion reliability to the glass (particularly, the adhesion reliability to the glass in a high temperature and high humidity environment) is improved, which is preferable.

The silane coupling agent is not particularly limited, but is limited to γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-phenyl-aminopropyltrimethoxysilane. Etc. are preferably mentioned. Of these, γ-glycidoxypropyltrimethoxysilane is preferable. Further, as a commercially available product, for example, the product name "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned. The silane coupling agent may be used alone or in combination of two or more.

The content of the silane coupling agent in the hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0, with respect to 100 parts by weight of the base polymer. It is 0.03 to 0.5 parts by weight.

The hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A may contain a polyol as long as the effects of the present invention are not impaired. When the pressure-sensitive adhesive layer A contains a polyol, for example, a cross-linked structure formed by a first cross-linking agent (particularly, the thermosetting cross-linking agent) is formed, and step absorption is improved, which is preferable.

The polyol is not particularly limited, and examples thereof include polyester polyols, polycarbonate polyols, polyacrylic polyols, polyether polyols, epoxy polyols, polyolefin polyols, and polyether ester polyols. Further, as a commercially available product, for example, the trade name "ADEKApolyether EPD-300" (manufactured by ADEKA Corporation) can be mentioned. The polyol may be used alone or in combination of two or more.

The content of the polyol in the hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 100 parts by weight, based on 100 parts by weight of the base polymer. It is 0.5 parts by weight.

Further, the hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A may contain a solvent. The solvent is not particularly limited, but esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane, Aromatic hydrocarbons such as methylcyclohexane; organic solvents such as ketones such as methylethylketone and methylisobutylketone can be mentioned. The solvent may be used alone or in combination of two or more.

The method for forming the pressure-sensitive adhesive layer A is not particularly limited, but as a first embodiment, the hybrid pressure-sensitive adhesive composition is applied (coated) on a support, and the obtained pressure-sensitive adhesive layer is dried and cured. In addition, the hybrid pressure-sensitive adhesive may be applied (coated) on the support, and the obtained pressure-sensitive adhesive layer may be irradiated with active energy rays to be cured. If necessary, it may be further heated and dried.
The above-mentioned dry curing, active energy ray irradiation, and heat drying proceed only with the curing by the cross-linking agent and the polymerization initiator constituting the first trigger, and are carried out by the cross-linking agent and the photopolymerization initiator constituting the second trigger. It is necessary to select conditions under which the curing reaction does not proceed or is suppressed.

The support is not particularly limited, but a plastic film is preferable. Examples of the material such as the plastic film include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethylmethacrylate (PMMA), polycarbonates, triacetylcellulose (TAC), polysulfone, polyallylates, and polyimides. Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "Arton" (cyclic olefin polymer, manufactured by JSR Co., Ltd.), trade name "Zeonoa" (cyclic olefin polymer, Nippon Zeon Co., Ltd.) Examples thereof include plastic materials such as cyclic olefin polymers (manufactured by the company). As these plastic materials, only one kind may be used, or two or more kinds may be used.
The support may be a release sheet. The release sheet is not particularly limited, and examples thereof include a plastic film surface-treated with a release treatment agent such as silicone-based, long-chain alkyl-based, fluorine-based, and molybdenum sulfide.

A known coating method can be used for applying (coating) the hybrid pressure-sensitive adhesive composition, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, and the like. Examples include coaters such as spray coaters, comma coaters, and direct coaters.

The drying and curing temperature is preferably 40 to 200 ° C, more preferably 50 to 180 ° C, and even more preferably 60 to 170 ° C. As the drying and curing time, an appropriate time can be adopted as appropriate, but it is, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, and more preferably 10 seconds to 5 minutes.

Examples of the active energy rays include ionizing radiation such as α-rays, β-rays, γ-rays, neutron rays, and electron beams, ultraviolet rays, and the like, and ultraviolet rays having the adhesive layer A exhibiting permeability are particularly preferable. .. That is, since the pressure-sensitive adhesive layer A has a high light-shielding property against visible light and a high transparency against ultraviolet rays, the base polymer can be cured by the ultraviolet rays. Further, the irradiation energy, irradiation time, irradiation method, etc. of the active energy ray are not particularly limited, and may be appropriately set so as to have a desired viscosity and viscoelasticity according to the thickness of the pressure-sensitive adhesive layer A and the like.

The main surface of the pressure-sensitive adhesive layer formed above, which does not face the support, is oxygen that inhibits photo-curing when the pressure-sensitive adhesive layer is photo-cured by the above-mentioned active energy rays and / or ultraviolet irradiation described later. It is preferable that the support is laminated with another support (including a release sheet) in order to block the light.

Further, as another preferable second embodiment of the method for forming the pressure-sensitive adhesive layer A, a method including the following steps can be mentioned.
(1) A single pressure-sensitive adhesive layer formed by the base polymer is formed.
(2) The pressure-sensitive adhesive layer is cured.
(3) Prepare a solution of the cross-linking agent and / or the photopolymerization initiator.
(4) The solution is applied to one surface of the cured pressure-sensitive adhesive layer, and the cross-linking agent and / or the photopolymerization initiator contained in the solution is thickened from the one side of the pressure-sensitive adhesive layer. Infiltrate in the direction.
(5) The pressure-sensitive adhesive layer is dried.

By forming the pressure-sensitive adhesive layer A according to the second embodiment, the curing reaction by the cross-linking agent and the polymerization initiator constituting the first trigger, and the cross-linking agent and the photopolymerization initiator constituting the second trigger are used. Since the curing reaction can be separated, it is not necessary to select the curing reaction conditions in which only the curing by the first trigger is carried out by the cross-linking agent and the polymerization initiator. The degree of freedom of combination with the cross-linking agent and the polymerization initiator constituting the trigger of No. 2 is remarkably improved.

Further, by separating the curing reaction by the cross-linking agent and the polymerization initiator constituting the first trigger from the curing reaction by the cross-linking agent and the photopolymerization initiator constituting the second trigger, the curing of the first trigger It becomes easy to adjust the step absorption of the obtained base polymer and the processability of the base polymer cured by the second trigger, and the photocurability has a pressure-sensitive adhesive layer A having more excellent step absorption and processability. The ease of designing the adhesive sheet A and the degree of freedom are also significantly improved.

FIG. 2 is a diagram (cross-sectional view) schematically showing a step for carrying out the second embodiment of the method for manufacturing the photocurable pressure-sensitive adhesive sheet A.
In FIG. 2A, first, the pressure-sensitive adhesive layer 10a formed of the base polymer is formed on the support S1.

In the pressure-sensitive adhesive layer forming step, first, a base polymer that does not contain a cross-linking agent and a photopolymerization initiator constituting the second trigger is applied (coated) on the support S1. As the support, the same support as in the first embodiment can be used.

A known coating method can be used for applying (coating) the base polymer, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, and the like. Examples include coaters such as comma coaters and direct coaters.

The main surface of the pressure-sensitive adhesive layer 10a formed above, which does not face the support S1, photo-cures the pressure-sensitive adhesive layer by active energy rays and / or ultraviolet irradiation described later in the pressure-sensitive adhesive layer curing step described later. In this case, it is preferable that the support S2 (including a release sheet) is laminated in order to block oxygen that inhibits photocuring.

Next, the pressure-sensitive adhesive layer 10a is cured (the pressure-sensitive adhesive layer curing step). In FIG. 2B, 10b is a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive layer 10a is cured. The method for curing the pressure-sensitive adhesive layer 10a is not particularly limited, and examples thereof include heating the pressure-sensitive adhesive layer 10a and irradiating the pressure-sensitive adhesive layer 10a with active energy rays to cure the pressure-sensitive adhesive layer 10a. If necessary, it may be further heated and dried. The specific curing conditions are the same as those in the first embodiment.
Since the drying curing, active energy ray irradiation, and heat drying in the pressure-sensitive adhesive layer curing step do not contain the cross-linking agent constituting the second trigger and the photopolymerization initiator, the cross-linking agent constituting the first trigger. Any condition can be adopted as long as the curing by the polymerization initiator proceeds, and the degree of freedom is much higher than that of the first embodiment.

The conditions for curing the pressure-sensitive adhesive layer 10a can be appropriately selected depending on the embodiment so that the pressure-sensitive adhesive layer 10b has desired physical properties. For example, the heating temperature and time, or the irradiation amount of the active energy ray may be appropriately set so that the pressure-sensitive adhesive layer 10b exhibits high fluidity and excellent step absorption.

FIG. 2B is an embodiment in which the pressure-sensitive adhesive layer 10a is irradiated with ultraviolet rays U to cure the pressure-sensitive adhesive layer 10a. Since the pressure-sensitive adhesive layer 10a constituting the pressure-sensitive adhesive layer A has a high light-shielding property against visible light and a high transparency against ultraviolet rays, it can be cured by the ultraviolet rays U.

The ultraviolet U may be directly irradiated to the pressure-sensitive adhesive layer 10a, but is preferably irradiated via a support in order to block oxygen that inhibits curing due to ultraviolet irradiation. FIG. 2B is an embodiment in which the pressure-sensitive adhesive layer 10a is irradiated with ultraviolet rays via the support S2. When ultraviolet rays are irradiated through the support, another support S2 (including a release sheet) is attached to the main surface opposite to the main surface facing the support S1 of the adhesive layer 10a to support the support. Irradiate ultraviolet rays through the body. The illuminance and time of ultraviolet irradiation are appropriately set depending on the composition of the base polymer, the thickness of the pressure-sensitive adhesive layer, and the like. For the ultraviolet irradiation, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave-excited lamp, a metal halide lamp, a chemical lamp, a black light, an LED, or the like can be used.

Next, as shown in FIG. 2C, after the support S2 is peeled off and removed, a solution 14 of the cross-linking agent 11 and / or the photopolymerization initiator 12 is applied to one surface of the pressure-sensitive adhesive layer 10b (solution). Coating process). Here, the cross-linking agent 11 and the photopolymerization initiator 12 are the cross-linking agent and the photopolymerization initiator constituting the second trigger.

The solution 14 may contain a solvent and may not contain a solvent if the cross-linking agent 11 functions as a solvent. FIG. 2C is an embodiment in which the solution 14 is a solution in which the cross-linking agent 11 and / or the photopolymerization initiator 12 is dissolved in the solvent 13.

The solvent 13 is not particularly limited as long as it can dissolve the cross-linking agent 11 and / or the photopolymerization initiator 12 and can swell the pressure-sensitive adhesive layer 10b, but the aqueous solvent has a wettability to the pressure-sensitive adhesive layer. A non-aqueous solvent is preferable because it is bad and the additive does not easily penetrate. The non-aqueous solvent is not particularly limited, and is, for example, an ester such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate and the like; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. Alicyclic ketones such as cyclopentanone and cyclohexanone; aliphatic hydrocarbons such as hexane, heptane and octane; alicyclic hydrocarbons such as cyclohexane; halogenated hydrocarbons such as chloroform, dichloromethane and 1,2-dichloroethane; Ethers such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxane; amides such as N, N-dimethylformamide, N, N-dimethylacetamide; nitriles such as acetonitrile, propionitrile, benzonitrile; methanol, ethanol, propanol, isopropanol, Examples thereof include alcohols such as n-butanol, isobutanol, sec-butanol, and tert-butanol, and esters, aromatic hydrocarbons, ketones, and alcohols are preferable. One type of solvent may be used alone, or two or more types may be used in combination.

The concentration of the cross-linking agent 11 and / or the photopolymerization initiator 12 in the solution 14 can be appropriately set, for example, 0.1 to 100% by weight, preferably 0.1 to 80% by weight, and more preferably 1. It can be selected from the range of ~ 70% by weight, more preferably 1.5 to 60% by weight, more preferably 3 to 50% by weight, still more preferably 5 to 40% by weight. When the concentration of the cross-linking agent 11 and / or the photopolymerization initiator 12 in the solution 14 is in this range, the pressure-sensitive adhesive layer 10b is sufficiently swollen while dissolving the cross-linking agent 11 and / or the photopolymerization initiator 12. Can be done.

The concentration of the cross-linking agent 11 in the solution 14 can be appropriately set, for example, 0.1 to 100% by weight, for example, 95% by weight or less (for example, 1 to 95% by weight, 1 to 90% by weight, 1 to 85% by weight). % 1 to 80% by weight, 1 to 60% by weight, etc.), for example, 1% by weight or more (for example, 1 to 95% by weight, 2 to 95% by weight) can be selected. If the concentration of the cross-linking agent is higher than the above range, the cross-linking agent 11 may bleed out or the distribution may vary from the viewpoint of coating leveling accuracy. In addition, if the concentration is lower than the above range, a solvent is required more than necessary, and the adhesive property deteriorates due to the residual solvent, and the adhesive swells more than necessary, resulting in an appearance defect (the surface becomes uneven). Etc. may occur.

A known coating method can be used for applying (coating) the solution 14 to the pressure-sensitive adhesive layer 10b, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, and the like. Examples include coaters such as knife coaters, spray coaters, comma coaters, and direct coaters.

The amount of the pressure-sensitive adhesive layer 10b of the solution 14 can be appropriately set, for example, 1 to 1000 μg / cm ² , preferably 1 to 500 μg / cm ² , more preferably 1 to 300 μg / cm ² , still more preferably 1. It can be selected from the range of ~ 100 μg / cm ² . When the coating amount of the solution 14 is within this range, the cross-linking agent 11 and / or the photopolymerization initiator 12 can be sufficiently applied to the pressure-sensitive adhesive layer 10b while dissolving the cross-linking agent 11 and / or the photopolymerization initiator 12. ..

After the solution 14 is applied to the pressure-sensitive adhesive layer 10b, it may be allowed to stand to allow the cross-linking agent 11 and / or the photopolymerization initiator 12 to permeate. The standing time is not particularly limited and may be appropriately selected from within 15 minutes, for example, from 1 second to 10 minutes, preferably from 5 seconds to 5 minutes. As the standing temperature, it can be carried out at room temperature (about 10 to 30 ° C.). When allowed to stand under the above conditions, the cross-linking agent 11 and / or the photopolymerization initiator 12 can be sufficiently permeated into the pressure-sensitive adhesive layer 10b.

The surface of the pressure-sensitive adhesive layer 10b is infiltrated with the solution 14 and swollen, and in the process, the cross-linking agent 11 and / or the photopolymerization initiator 12 in the solution 14 permeates into the pressure-sensitive adhesive layer 10b in the thickness direction ( Solution infiltration step). This state is shown in FIG. 2 (d). The cross-linking agent 11 and / or the photopolymerization initiator 12 permeates the pressure-sensitive adhesive layer 10b in a dissolved state. Therefore, the cross-linking agent 11 and / or the photopolymerization initiator 12 is in a "dissolved" state in the pressure-sensitive adhesive layer 10b.

Further, in the process of the cross-linking agent 11 and / or the photopolymerization initiator 12 permeating into the pressure-sensitive adhesive layer 10b, a concentration gradient can be formed in the thickness direction. Therefore, the concentration of the cross-linking agent 11 and / or the photopolymerization initiator 12 on the surface side to which the solution 14 is applied can be higher than that on the opposite surface side. This state is shown in FIG. 2 (d).

Then, by drying the pressure-sensitive adhesive layer 10b, the pressure-sensitive adhesive layer 10 shown in FIG. 2 (e) can be obtained (drying step). When the solution 14 contains the solvent 13, the solvent 13 evaporates by the drying step. By the drying step, the pressure-sensitive adhesive layer 10b returns to a state close to that before swelling. When the pressure-sensitive adhesive layer 10b is dried, the permeation of the cross-linking agent 11 and / or the photopolymerization initiator 12 into the pressure-sensitive adhesive layer 10b is stopped, and the concentration gradient of the cross-linking agent 11 and / or the photopolymerization initiator 12 is fixed. Will be done.

The heating and drying temperature in the drying step is preferably 40 to 200 ° C, more preferably 50 to 180 ° C, and even more preferably 60 to 170 ° C. As the drying time, an appropriate time may be adopted as appropriate, but it is, for example, 5 seconds to 20 minutes, preferably 5 seconds to 10 minutes, and more preferably 10 seconds to 5 minutes. By drying under the above conditions, the pressure-sensitive adhesive layer 10 can be returned to a state close to that before coating.
Further, if necessary, a standing time may be provided to make the cross-linking agent and the pressure-sensitive adhesive layer more uniform. The standing time is not particularly limited and may be appropriately selected from within 30 days, for example, from 1 hour to 15 days, preferably from 24 hours to 10 days. By allowing the pressure-sensitive adhesive layer 10 to stand still, the cross-linking agent and the pressure-sensitive adhesive layer are stabilized, and variations in characteristic evaluation can be suppressed.

The photocurable pressure-sensitive adhesive sheet 1B shown in FIG. 2E includes a photo-curing pressure-sensitive adhesive layer 10 composed of a hybrid pressure-sensitive adhesive composition containing a base polymer, a cross-linking agent 11, and a photopolymerization initiator 12. It is one of the embodiments of the sex-sensitive adhesive sheet A.

In the second embodiment, the base polymer comprises a first cross-linking agent and a first polymerization initiator as a first trigger, and the pressure-sensitive adhesive layer curing step comprises the first cross-linking agent and the first polymerization agent. Curing by the reaction of the polymerization initiator, the cross-linking agent 11 and the photopolymerization initiator 12 serve as a second trigger.

After the pressure-sensitive adhesive layer curing step, either or both of the first cross-linking agent and the first polymerization initiator may remain. In that case, as the cross-linking agent 11 and the photopolymerization initiator 12, only one of the second cross-linking agent and the second polymerization initiator can be used, and preferably the second cross-linking agent (cross-linking agent 11). ) Can only be used. However, it is also possible to use both a second cross-linking agent and a second polymerization initiator.

In the second embodiment, the degree of freedom in combining the first trigger and the second trigger is extremely wide. That is, there is no limitation on the combination of the polymerization initiator, for example, both the first trigger and the second trigger are the combination of the photopolymerization initiator, the first trigger is the thermal polymerization initiator and the second trigger is the photopolymerization. The combination of initiators can be freely selected. Further, when both the first trigger and the second trigger are a combination of photopolymerization initiators, it is possible that the light absorption wavelength bands of the two types of photopolymerization initiators overlap or approximate. Furthermore, the same polymerization initiator can be combined as the first trigger and the second trigger, which was not possible with the conventional hybrid pressure-sensitive adhesive sheet.
Further, the combination of the cross-linking agents is not limited, and the same cross-linking agent can be used as the first trigger and the second trigger.

FIG. 3A is a cross-sectional view showing an embodiment of the photocurable pressure-sensitive adhesive sheet A of the present invention, and FIG. 3B is a cross-sectional view showing another embodiment of the photocurable pressure-sensitive adhesive sheet A of the present invention. ..

Referring to FIG. 3A, in the photocurable pressure-sensitive adhesive sheet 1C according to the embodiment of the present invention, a support is attached to the pressure-sensitive adhesive layer 10 and the first main surface 10A of one of the pressure-sensitive adhesive layers 10. It is composed of a support S1 which is not combined and is made of a release sheet bonded to the other second main surface 10B of the pressure-sensitive adhesive layer 10.

Referring to FIG. 3B, the photocurable pressure-sensitive adhesive sheet 1D according to the embodiment of the present invention is a release sheet bonded to the pressure-sensitive adhesive layer 10 and the first main surface 10A of the pressure-sensitive adhesive layer 10. It is composed of a first support S2 made of, and a second support S1 made of a release sheet bonded to the other second main surface 10B of the pressure-sensitive adhesive layer 10. The photocurable pressure-sensitive adhesive sheet 1D can be obtained by attaching the support S2 to the first main surface 10A of the photo-curable pressure-sensitive adhesive sheet 1C.

In FIGS. 3A and 3B, the dotted line XX'is a line that divides the pressure-sensitive adhesive layer 10 into two equal parts in the thickness direction. If the thickness of the pressure-sensitive adhesive layer 10 is not uniform, the dotted line XX'is a line that bisects the thickness at each point.

In FIG. 3, the pressure-sensitive adhesive layer 10 is a single layer made of a base polymer and having two facing main surfaces (a first main surface and a second main surface). The pressure-sensitive adhesive layer 10 can be formed by the method of the second embodiment described above, and corresponds to the pressure-sensitive adhesive layer 10 of FIG.

When the pressure-sensitive adhesive layer is "single layer", it means that it is not a laminated structure. For example, a pressure-sensitive adhesive layer made of a base polymer and a pressure-sensitive adhesive layer made of the same b-spolymer on the pressure-sensitive adhesive layer has a laminated structure, not a single layer. Similarly, a pressure-sensitive adhesive layer composed of a base polymer containing a cross-linking agent and / or a photopolymerization initiator is formed, and a base polymer in which the cross-linking agent and / or the photopolymerization initiator is dissolved at different concentrations is further formed. What formed the pressure-sensitive adhesive layer is a laminated structure, not a single layer.

The thickness of the pressure-sensitive adhesive layer 10 is not particularly limited, but is usually 5 μm to 500 μm, preferably 5 μm to 400 μm, and more preferably 5 μm to 350 μm. When the thickness of the pressure-sensitive adhesive layer 10 is within this range, it is suitable for forming a concentration gradient of the cross-linking agent and / or the photopolymerization initiator in the thickness direction of the pressure-sensitive adhesive layer 10.

The cross-linking agent 11 and / or the photopolymerization initiator 12 is formed by the permeation of the cross-linking agent 11 and / or the photopolymerization initiator 12 into the pressure-sensitive adhesive layer 10 by the solution coating step, the solution permeation step, and the drying step. Then, as shown in FIG. 3, a concentration gradient of the cross-linking agent 11 and / or the photopolymerization initiator 12 may occur in the thickness direction of the pressure-sensitive adhesive layer 10. Therefore, when the single-layer pressure-sensitive adhesive layer 10 is divided into two equal parts in the thickness direction, the cross-linking agent 11 and / or photopolymerization initiation in the region to which the first main surface 10A of one of the two main surfaces belongs. The concentration of the agent 12 and the concentration of the cross-linking agent 11 and / or the photopolymerization initiator 12 in the region to which the other second main surface 10B belongs are different. The case where the cross-linking agent 11 and / or the photopolymerization initiator 12 is not present in the region having the lower concentration (concentration is 0) is also included in the scope of the present invention.

The concentration of the region to which the first main surface belongs and the concentration of the region to which the second main surface belongs are the cross-linking agent 11 and / or light in each region when there is also a concentration gradient in each region. It shall mean the average concentration of the polymerization initiator 12.

In FIG. 3A, the second main surface 10B faces the support S1 and the cross-linking agent 11 and / or the photopolymerization initiator 12 in the region to which the first main surface 10A belongs. It is an embodiment showing that the concentration is higher than the concentration of the cross-linking agent 11 and / or the photopolymerization initiator 12 in the region to which the second main surface 10B belongs, and the cross-linking agent 11 and / or the cross-linking agent 11 and / or the photopolymerization initiator 12 are on the first main surface 10A. / Or a solution of the photopolymerization initiator 12 is applied, and the cross-linking agent 11 and / or the photopolymerization initiator 12 permeates into the pressure-sensitive adhesive layer 10 from the first main surface 10A to a depth in the thickness direction in a dissolved state. It can be obtained by doing so.

As a result of the concentration gradient of the cross-linking agent 11 and / or the photopolymerization initiator 12 in the pressure-sensitive adhesive layer 10 in the thickness direction, when the pressure-sensitive adhesive layer 10 is cured, a difference in cross-linking density may occur on the front and back surfaces. That is, in FIG. 3, the region to which the main surface 10A belongs can produce a higher crosslink density than the region to which the main surface 10B belongs. This configuration is preferable because, for example, when the photocurable pressure-sensitive adhesive sheet A is used as a flexible image display device that bends the side of the main surface 10A outward, the flexibility can be improved. That is, when the flexible display is bent, a tensile stress is generally applied to the outside and a compressive stress is applied to the inside, and the stress on the outside is stronger than the stress on the inside. Therefore, by arranging the main surface 10A of the pressure-sensitive adhesive layer 10 on the outside when the flexible display is bent, the durability against bending can be improved.

Another third embodiment of the hybrid pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer A is a pressure-sensitive adhesive composition containing a polymer having a benzophenone structure in a side chain (hereinafter, may be referred to as “BP polymer”). Examples thereof include materials (hereinafter, may be referred to as "BP type hybrid pressure-sensitive adhesive composition"). The "benzophenone structure" serves as a second trigger in the hybrid adhesive.

A preferable example of the BP polymer is an acrylic polymer having a benzophenone structure in the side chain. The BP polymer is preferably a polymer that does not substantially contain an ethylenically unsaturated group.

As used herein, the term "benzophenone structure" refers to a diallyl ketone structure represented by the general formula: Ar ^1- (C = O) -Ar ^2- ; or -Ar ^3- (C = O) -Ar ^2- ; To say. Here, Ar ¹ in the above general formula is selected from phenyl groups which may have a substituent. Ar ² and Ar ³ in the above general formula are independently selected from phenylene groups which may have a substituent. Ar ² and Ar ³ may be the same or different. The benzophenone structure can be excited by irradiation with ultraviolet light, and in the excited state, hydrogen radicals can be extracted from other molecules or other parts of the molecules.

The pressure-sensitive adhesive layer formed from the BP-type hybrid pressure-sensitive adhesive composition utilizes the hydrogen radical extraction reaction by exciting the benzophenone structure by containing a polymer (BP polymer) having a benzophenone structure in the side chain. It is possible to form a crosslinked structure. As the polymer having the benzophenone structure in the side chain, Ar ¹ in the above general formula: Ar ¹ − (C = O) − Ar ² −; is a phenyl group which may have a substituent, and Ar ² is A polymer having a benzophenone structure, which is a phenylene group which may have a substituent, in the side chain is preferable. When at least one of Ar ¹ and Ar ² has one or more substituents, the substituents are independently alkoxy groups (for example, alkoxy groups having 1 to 3 carbon atoms, preferably methoxy groups). It can be selected from the group consisting of halogen atoms (eg, F, Cl, Br, etc., preferably Cl or Br), hydroxyl groups, amino groups and carboxyl groups.

The BP polymer may have a side chain in which the benzophenone structure as described above is directly bonded to the main chain, and the BP polymer has a main chain via one or more of an ester bond, an oxyalkylene structure, and the like. It may have a bound side chain. A preferred example of the BP polymer is a polymer containing a repeating unit derived from a compound having an ethylenically unsaturated group and a benzophenone structure in the molecule (hereinafter, may be referred to as “ethylenically unsaturated BP”). The repeating unit may be a polymerization residue reacted with an ethylenically unsaturated group of the corresponding ethylenically unsaturated BP.

Examples of the ethylenically unsaturated BP include 4-acryloyloxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxyethoxy-4'-methoxybenzophenone, and 4-acryloyloxy-4'-bromobenzophenone. Acryloyloxybenzophenone, which may have a substituent, such as 2-hydroxy-4-acryloyloxybenzophenone; 4-[(2-acryloyloxy) ethoxy] benzophenone, 4-[(2-acryloyloxy) ethoxy]. Acryloyloxyalkoxybenzophenone which may have a substituent such as -4'-bromobenzophenone; 4-methacryloyloxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone. , 4-Methacloyloxyethoxy-4'-bromobenzophenone, 2-hydroxy-4-methacryloyloxybenzophenone, and the like, which may have substituents; 4-[(2-methacryloyloxy) ethoxy] benzophenone. , 4-[(2-methacryloyloxy) ethoxy] -4'-methoxybenzophenone and the like, which may have a substituent, methacryloyloxyalkoxybenzophenone; 4-vinylbenzophenone, 4'-bromo-3-vinylbenzophenone, Examples thereof include, but are not limited to, vinylbenzophenone which may have a substituent, such as 2-hydroxy4-methoxy-4'-vinylbenzophenone. Ethylene unsaturated BPs can be used alone or in combination of two or more to prepare BP polymers. As the ethylenically unsaturated BP, a commercially available product can be used, and the ethylenically unsaturated BP can be synthesized by a known method. From the viewpoint of reactivity and the like, an ethylenically unsaturated BP having a (meth) acryloyl group, that is, an ethylenically unsaturated BP which is an acrylic monomer can be preferably adopted.

The BP polymer is a repeating unit derived from an ethylenically unsaturated BP and a repeating unit derived from an ethylenically unsaturated compound (hereinafter, also referred to as “another ethylenically unsaturated compound”) that does not correspond to the ethylenically unsaturated BP. It may be a copolymer having a unit. Such a BP polymer can be a copolymer of a monomer component containing the ethylenically unsaturated BP and the other ethylenically unsaturated compound. Further, the BP polymer may also be a copolymer obtained by copolymerizing a partial polymer (prepolymer) of a monomer mixture composed of only the other ethylenically unsaturated compound and the ethylenically unsaturated BP. As the other ethylenically unsaturated compound, one or more acrylic monomers may be preferably adopted. A preferable example of the BP polymer is an acrylic BP polymer in which more than 50% by weight (preferably more than 70% by weight, for example, more than 90% by weight) of the monomer component constituting the BP polymer is an acrylic monomer.

As the acrylic monomer as the other ethylenically unsaturated compound, the same acrylic acid alkyl ester having a linear or branched alkyl group constituting the monomer unit of the acrylic polymer is used. obtain. The monomer component constituting the BP polymer is composed of the alicyclic monomer, the hydroxyl group-containing monomer, the nitrogen atom-containing monomer, and the carboxy group-containing monomer constituting the monomer unit of the acrylic polymer as the other ethylenically unsaturated compounds. It may contain one or more selected species.

The BP-type hybrid pressure-sensitive adhesive composition is a photocurable acrylic pressure-sensitive adhesive composition in which more than 50% by weight (preferably more than 70% by weight, for example, more than 90% by weight) of the total constituent monomer components are acrylic monomers. possible. The photocurable acrylic pressure-sensitive adhesive composition forms an acrylic photocurable product by photocuring.

The weight average molecular weight (Mw) of the BP polymer is not particularly limited and may be, for example, about 0.5 × 10 ⁴ to 500 × 10 ⁴ . From the viewpoint of the cohesiveness of the pressure-sensitive adhesive layer A and the handleability of the photocurable pressure-sensitive adhesive sheet A, it is usually appropriate that the Mw of the BP polymer is 1 × 10 ⁴ or more, and 5 × 10 ⁴ or more. It may be 10 × 10 ⁴ or more, 15 × 10 ⁴ or more, or 20 × 10 ⁴ or more. Further, from the viewpoint of the step absorption of the pressure-sensitive adhesive layer A, the Mw of the BP polymer is usually preferably 200 × 10 ⁴ or less, preferably 150 × 10 ⁴ or less, and preferably 100 × 10 ⁴ or less. It may be less than or equal to, 70 × 10 ⁴ or less, and 50 × 10 ⁴ or less.
The weight average molecular weight (Mw) of the polymer means a value in terms of standard polystyrene obtained by gel permeation chromatography (GPC). As the GPC apparatus, for example, a model name “HLC-8320GPC” (column: TSKgelGMH-H (S), manufactured by Tosoh Corporation) can be used.

The glass transition temperature (Tg) of the BP polymer is not particularly limited. The Tg of the BP polymer may be, for example, −80 ° C. or higher and 150 ° C. or lower, −80 ° C. or higher and 50 ° C. or lower, or −80 ° C. or higher and 10 ° C. or lower. From the viewpoint of the step absorption of the pressure-sensitive adhesive layer A, the Tg of the BP polymer is preferably less than 0 ° C., preferably −10 ° C. or lower, preferably −20 ° C. or lower, and may be −30 ° C. or lower. However, it may be −40 ° C. or lower, or −50 ° C. or lower. Further, from the viewpoint of the cohesiveness of the pressure-sensitive adhesive layer A and the improvement of processability after photo-curing, it is usually advantageous that the Tg of the BP polymer is −75 ° C. or higher, and may be −70 ° C. or higher. In some embodiments, the Tg of the BP polymer may be −55 ° C. or higher, or −45 ° C. or higher. The Tg of the BP polymer can be adjusted by the type and amount of the monomer components constituting the BP polymer.

Here, the glass transition temperature (Tg) of the polymer means the glass transition temperature obtained by the Fox formula based on the composition of the monomer components constituting the polymer. As shown below, the Fox formula is a relational formula between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer.
1 / Tg = Σ (Wi / Tgi)
In the above Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on the weight), and Tgi is the monomer i. Represents the glass transition temperature (unit: K) of the homopolymer.

As the glass transition temperature of the homopolymer used for calculating Tg, the value described in the publicly known material shall be used. For example, for the monomers listed below, the following values are used as the glass transition temperature of the homopolymer of the monomer.
2-Ethylhexyl acrylate: -70 ° C
n-Butyl acrylate: -55 ° C
Isostearyl acrylate: -18 ° C
Methyl methacrylate: 105 ° C
Methyl acrylate: 8 ° C
Cyclohexyl acrylate: 15 ° C
N-vinyl-2-pyrrolidone: 54 ° C
2-Hydroxyethyl acrylate: -15 ° C
4-Hydroxybutyl acrylate: -40 ° C
Isobornyl acrylate: 94 ° C
Acrylic acid: 106 ° C
Methacrylic acid: 228 ° C

For the glass transition temperature of homopolymers of monomers other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) shall be used. When multiple types of values are described in this document, the highest value is adopted. For the monomer in which the glass transition temperature of the homopolymer is not described in the Polymer Handbook, the value obtained by the measuring method described in JP-A-2007-51271 shall be used. For a polymer for which a nominal value of glass transition temperature is provided by a manufacturer or the like, the nominal value may be adopted.

The BP polymer preferably contains a benzophenone structure in an amount of, for example, about 0.5 mg or more in terms of 4-benzoylphenyl acrylate, per 1 g of the polymer. Hereinafter, the value obtained by converting the number of benzophenone structures contained in 1 g of the BP polymer into the amount converted to 4-benzoylphenyl acrylate may be referred to as the BP equivalent (unit: mg / g) of the BP polymer. For example, if it contains 40 μmol of benzophenone structure per gram, the BP equivalent of the polymer is calculated to be 10 mg / g.

From the viewpoint of obtaining a higher photocuring effect (for example, the effect of enhancing processability by photocuring), it is generally appropriate that the BP equivalent of the BP polymer is 0.11 mg / g or more in some embodiments. , 0.5 mg / g or more, 1 mg / g or more, 5 mg / g or more, 8 mg / g or more, 10 mg / g or more, 15 mg / g or more, 20 mg / g or more. good. Further, in some embodiments, the BP equivalent of the BP polymer is usually 100 mg / g or less, and 80 mg / g, from the viewpoint of enhancing the impact resistance and peel strength of the joint portion due to the photocured product. It may be less than or equal to, 60 mg / g or less, 40 mg / g or less, 25 mg / g or less, and 15 mg / g or less. The BP equivalent of the BP polymer can be adjusted by the composition of the monomer components constituting the BP polymer.

In addition, from the viewpoint of reducing the peeling force by photocuring and performing rework or repair, the BP equivalent is preferably 50 mg / g or more, and may be 100 mg / g or more.

The weight ratio of the BP polymer in the entire BP-type hybrid pressure-sensitive adhesive composition, that is, the weight fraction of the BP polymer in the BP-type hybrid pressure-sensitive adhesive composition is not particularly limited, and the step absorption of the pressure-sensitive adhesive layer A and its step-absorbing property thereof. It can be set so as to have a good balance with the processability of the photocured product. In some embodiments, the weight fraction of the BP polymer may be, for example, 1% by weight or more, usually 5% by weight or more, 10% by weight or more, and 15% by weight or more. It may be 25% by weight or more, 35% by weight or more, 45% by weight or more, or 55% by weight or more. As the weight fraction of the BP polymer increases, the above-mentioned G'a10 / G'b85 tends to increase.
It can also be carried out in an embodiment in which the weight fraction of the BP polymer in the BP type hybrid pressure-sensitive adhesive composition is substantially 100% by weight (for example, 99.5% by weight or more). Further, from the viewpoint of ease of adhesive performance, in some embodiments, the weight fraction of the BP polymer in the BP type hybrid pressure-sensitive adhesive composition may be, for example, less than 99% by weight or less than 95% by weight. It may be less than 85% by weight, less than 70% by weight, less than 50% by weight, or less than 40% by weight.

It is preferable that 1 g of the BP-type hybrid pressure-sensitive adhesive composition contains, for example, about 0.1 mg or more of the benzophenone structure in terms of 4-benzoylphenyl acrylate. Hereinafter, the weight of the benzophenone structure in terms of 4-benzoylphenyl acrylate contained in 1 g of the BP-type hybrid pressure-sensitive adhesive composition may be referred to as the BP equivalent (unit: mg / g) of the BP-type hybrid pressure-sensitive adhesive composition. From the viewpoint of obtaining a higher photocuring effect (for example, the effect of enhancing processability by photocuring), in some embodiments, the BP equivalent of the BP type hybrid pressure-sensitive adhesive composition is usually 0.3 mg / g or more. It may be 0.5 mg / g or more, 1 mg / g or more, 5 mg / g or more, 10 mg / g or more, or 20 mg / g or more. Further, in some embodiments, the BP equivalent of the BP-type hybrid pressure-sensitive adhesive composition is usually 100 mg / g or less from the viewpoint of impact resistance of the joint portion by the photo-cured product and suppression of strain in the photo-cured product. It may be 80 mg / g or less, 60 mg / g or less, 40 mg / g or less, 25 mg / g or less, or 15 mg / g or less.

The BP-type hybrid pressure-sensitive adhesive composition may be a pressure-sensitive adhesive composition containing an ethylenically unsaturated compound and a BP polymer. The BP-type hybrid pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive in which more than 50% by weight (preferably more than 70% by weight, for example, more than 90% by weight) of the total monomer components constituting the pressure-sensitive adhesive composition is an acrylic-based monomer. It can be a composition.

Examples of the ethylenically unsaturated compound include an acrylic acid alkyl ester having a linear or branched alkyl group constituting the monomer unit of the acrylic polymer, an alicyclic monomer, a hydroxyl group-containing monomer, and a nitrogen atom-containing monomer. , Carboxy group-containing monomers, polyfunctional (meth) acrylates and the like can be used.

The ethylenically unsaturated compound may contain an acrylic acid alkyl ester in a proportion of 40% by weight or more. The ratio of the acrylic acid alkyl ester to the monomer component may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more. Further, from the viewpoint of enhancing the cohesiveness of the pressure-sensitive adhesive layer A, it is usually appropriate that the ratio of the acrylic acid alkyl ester to the ethylenically unsaturated compound is 99.5% by weight or less, and even if it is 95% by weight or less. It may be 85% by weight or less, 70% by weight or less, or 60% by weight or less.

When the alicyclic monomer is used, the amount used is not particularly limited, and may be, for example, 1% by weight or more, 3% by weight or more, or 5% by weight or more of the entire monomer component. In one aspect, the amount of the alicyclic monomer used may be 10% by weight or more of the total monomer component, or 15% by weight or more. It is appropriate that the upper limit of the amount of the alicyclic monomer used is about 40% by weight or less, for example, 30% by weight or less, 25% by weight or less (for example, 15% by weight or less, and further 10% by weight). % Or less). Alternatively, the alicyclic monomer may not be used as the ethylenically unsaturated compound.

When a nitrogen atom-containing monomer is used, the amount used is not particularly limited, and may be, for example, 1% by weight or more, 2% by weight or more, or 3% by weight or more of the entire monomer component. It may be 5% by weight or more or 7% by weight or more. In one aspect, the amount of the nitrogen atom-containing monomer used may be 10% by weight or more, 15% by weight or more, or 20% by weight or more of the total monomer component. Further, it is appropriate that the amount of the nitrogen atom-containing monomer used is, for example, 40% by weight or less of the entire monomer component, 35% by weight or less, 30% by weight or less, or 25% by weight or less. good. In another aspect, the amount of the nitrogen atom-containing monomer used may be, for example, 20% by weight or less of the total monomer component, or 15% by weight or less. Alternatively, the nitrogen atom-containing monomer may not be used as the ethylenically unsaturated compound.

When a hydroxyl group-containing monomer is used, the amount used is not particularly limited, and may be, for example, 0.01% by weight or more, 0.1% by weight or more, or 0.5% by weight or more of the entire monomer component. It may be 1% by weight or more, 5% by weight or more, or 10% by weight or more. Further, from the viewpoint of suppressing water absorption of the BP type hybrid pressure-sensitive adhesive composition or the pressure-sensitive adhesive layer A, it is appropriate that the amount of the hydroxyl group-containing monomer used is, for example, 40% by weight or less of the total monomer component in some embodiments. It may be 30% by weight or less, 25% by weight or less, or 20% by weight or less. In another aspect, the amount of the hydroxyl group-containing monomer used may be, for example, 15% by weight or less of the total monomer component, 10% by weight or less, or 5% by weight or less. Alternatively, the hydroxyl group-containing monomer may not be used as the ethylenically unsaturated compound.

When a carboxy group-containing monomer is used, the amount used is not particularly limited, and the proportion of the total monomer component may be, for example, 2% by weight or less, 1% by weight or less, and 0.5% by weight or less (for example). It may be less than 0.1% by weight). The BP-type hybrid pressure-sensitive adhesive composition does not have to substantially contain a carboxy group-containing monomer as a constituent monomer component thereof. Here, the fact that the carboxy group-containing monomer is not substantially contained means that the carboxy group-containing monomer is not used at least intentionally. This can be advantageous from the viewpoint of the metal corrosion inhibitory property of the pressure-sensitive adhesive layer A formed from the BP-type hybrid pressure-sensitive adhesive composition and the photocurable product thereof.

When the polyfunctional (meth) acrylate is used, the amount used is not particularly limited and may be less than 5.0% by weight of the total monomer components constituting the BP type hybrid pressure-sensitive adhesive composition. As a result, it is possible to prevent the formation of an excessive crosslinked structure during the formation of the pressure-sensitive adhesive layer A (that is, at the stage before photo-curing), and to enhance the step absorption of the pressure-sensitive adhesive layer A. The amount of the polyfunctional (meth) acrylate used may be, for example, 4.0% by weight or less of the total monomer component, 3.0% by weight or less, or 2.0% by weight or less. It may be 0% by weight or less, 0.5% by weight or less, or 0.3% by weight or less. It is not necessary to use polyfunctional (meth) acrylate. Further, in some embodiments, the amount of the polyfunctional (meth) acrylate used with respect to the entire monomer component may be, for example, 0.001% by weight or more from the viewpoint of imparting appropriate cohesiveness to the pressure-sensitive adhesive layer A. , 0.005% by weight or more, 0.01% by weight or more, or 0.03% by weight or more. Alternatively, the polyfunctional (meth) acrylate may not be used as the ethylenically unsaturated compound.

The weight ratio of the BP polymer to the total amount of the BP polymer and the ethylenically unsaturated compound contained in the BP type hybrid pressure-sensitive adhesive composition is not particularly limited, and the pressure-sensitive adhesive layer A formed from the pressure-sensitive adhesive composition is not particularly limited. It can be set so that the step absorption property and the processability of the photo-cured product are suitably balanced. In some embodiments, the weight fraction of the BP polymer may be, for example, 0.5% by weight or more, usually 1% by weight or more, preferably 1.5% by weight or more, more preferably 5% by weight or more. From the viewpoint of enhancing the effect of photocuring, it may be 10% by weight or more, 15% by weight or more, 25% by weight or more, 35% by weight or more, or 45% by weight or more. , 55% by weight or more. Further, from the viewpoint of ease of preparation and coatability of the pressure-sensitive adhesive composition, in some embodiments, the weight ratio of the BP polymer to the total amount may be, for example, less than 99% by weight, 95% by weight. It may be less than 85% by weight, less than 70% by weight, less than 50% by weight, or less than 40% by weight.

The ratio of the weight of the organic solvent to the total weight of the BP-type hybrid pressure-sensitive adhesive composition may be, for example, 30% by weight or less, preferably 20% by weight or less, and 10% by weight or less. It is preferable, and it is more preferable that it is 5% by weight or less. In some embodiments, the weight ratio of the organic solvent may be 3% by weight or less, 1% by weight or less, 0.5% by weight or less, 0.1% by weight or less, 0.05% by weight or less. % Or less, and it does not have to contain substantially an organic solvent.

The BP-type hybrid pressure-sensitive adhesive composition is measured under the conditions of viscosity (BH-type viscometer, No. 5 rotor, 10 rpm, measurement temperature of 30 ° C.) from the viewpoint of coatability in the normal temperature range. ) Is preferably 1000 Pa · s or less, preferably 100 Pa · s or less, and more preferably 50 Pa · s or less. The viscosity of the BP-type hybrid pressure-sensitive adhesive composition may be, for example, 30 Pa · s or less, 20 Pa · s or less, 10 Pa · s or less, or 5 Pa · s or less. The lower limit of the viscosity of the BP-type hybrid pressure-sensitive adhesive composition is not particularly limited, but is usually 0 from the viewpoint of suppressing the repelling of the pressure-sensitive adhesive composition within the coating range and the protrusion of the pressure-sensitive adhesive composition at the outer edge of the coating range. .1 Pa · s or more is appropriate, and may be 0.5 Pa · s or more, or 1 Pa · s or more.

The BP-type hybrid pressure-sensitive adhesive composition contains at least a compound having one ethylenically unsaturated group (that is, a monofunctional monomer) as the ethylenically unsaturated compound. As the monofunctional monomer, the corresponding compound can be selected and used from the above-mentioned examples of the ethylenically unsaturated compound. The monofunctional monomer may be used alone or in combination of two or more.

The weight ratio of the monofunctional monomer to the total amount of the BP polymer and the ethylenically unsaturated compound may be, for example, 1% by weight or more, 5% by weight or more, or 15% by weight or more. In some embodiments, the weight ratio of the monofunctional monomer may be 25% by weight or more, or 35% by weight or more, from the viewpoint of ease of preparation and coatability of the BP type hybrid pressure-sensitive adhesive composition. It may be 45% by weight or more. The weight ratio of the monofunctional monomer to the total amount is, for example, 99% by weight or less, usually 95% by weight or less, 85% by weight or less, and 75% by weight. It may be less than or equal to 65% by weight, may be 55% by weight or less, and may be 45% by weight or less.

In an embodiment in which the BP type hybrid pressure-sensitive adhesive composition contains a monofunctional monomer, the glass transition temperature (Tg) determined by the Fox formula based on the composition of the monofunctional monomer is not particularly limited, and is, for example, −80 ° C. It can be 250 ° C. or higher. The Tg based on the composition of the monofunctional monomer is usually preferably 150 ° C. or lower, and may be 100 ° C. or lower, from the viewpoint of compatibility between the polymer derived from the monofunctional monomer and other components. It may be 70 ° C. or lower, 50 ° C. or lower, or 30 ° C. or lower. In some embodiments, the Tg based on the composition of the monofunctional monomer is preferably less than 0 ° C., more preferably −10 ° C. or lower, from the viewpoint of the step absorption of the pressure-sensitive adhesive layer A. It may be −20 ° C. or lower, −30 ° C. or lower, or −40 ° C. or lower. Further, from the viewpoint of the cohesiveness of the pressure-sensitive adhesive layer A and the processability after photo-curing, it is usually advantageous that the Tg based on the composition of the monofunctional monomer is −60 ° C. or higher, and even at −54 ° C. or higher. It may be −50 ° C. or higher, −45 ° C. or higher, −35 ° C. or higher, or −25 ° C. or higher. The Tg can be adjusted by the compound used as the monofunctional monomer and the usage ratio thereof.

In a BP-type hybrid pressure-sensitive adhesive composition containing a BP polymer and a monofunctional monomer, a pressure-sensitive adhesive layer A formed from the pressure-sensitive adhesive composition, and a photocured product thereof, the BP polymer Tg (hereinafter referred to as "Tg _A "). ) And Tg based on the monomer composition of the monofunctional monomer (hereinafter, also referred to as Tg _B1 ) is a Tg difference [° C] (hereinafter, also referred to as ΔTg) calculated by Tg _B1 [° C] − Tg _A [° C]. ) Can be set to be, for example, in the range of −50 ° C. or higher and 70 ° C. or lower. The fact that the absolute value of the Tg difference is not too large may be advantageous from the viewpoint of compatibility in the pressure-sensitive adhesive layer A and its photo-cured product. In some embodiments, ΔTg may be, for example, −10 ° C. or higher, preferably 0 ° C. or higher, 7 ° C. or higher, 10 ° C. or higher, 20 ° C. or higher, or 30 ° C. or higher. good.

The BP-type hybrid pressure-sensitive adhesive composition may contain at least a compound having two or more ethylenically unsaturated groups (that is, a polyfunctional monomer) as the ethylenically unsaturated compound. The polyfunctional monomer may be used alone or in combination of two or more from the above-mentioned examples of the polyfunctional monomer. The amount of the polyfunctional monomer used can be set in the same manner as the ratio of the polyfunctional (meth) acrylate in the entire monomer component constituting the pressure-sensitive adhesive composition.

In the embodiment in which the monofunctional monomer and the polyfunctional monomer are used in combination as the ethylenically unsaturated compound, the weight ratio of the monofunctional monomer to the ethylenically unsaturated compound may be, for example, 1% by weight or more, and is usually used. It is appropriate that it is 25% by weight or more, 50% by weight or more, 75% by weight or more, 95% by weight or more, or 99% by weight or more. The weight ratio of the monofunctional monomer to the ethylenically unsaturated compound may be, for example, 99.9% by weight or less, or 99.8% by weight or less.

In the BP-type hybrid pressure-sensitive adhesive composition, the ethylenically unsaturated compound may be contained in the form of a partially polymerized product, or the entire amount thereof may be contained in the form of an unreacted monomer. The pressure-sensitive adhesive composition according to a preferred embodiment contains an ethylenically unsaturated compound in the form of a partial polymer. The polymerization method for partially polymerizing an ethylenically unsaturated compound is not particularly limited, and for example: photopolymerization performed by irradiating light such as ultraviolet rays; radiation polymerization performed by irradiating radiation such as β-rays and γ-rays ;: Various conventionally known polymerization methods such as solution polymerization, emulsion polymerization, thermal polymerization such as bulk polymerization; and the like can be appropriately selected and used. From the viewpoint of efficiency and convenience, the photopolymerization method can be preferably adopted. According to photopolymerization, the polymerization conversion rate (monomer conversion) can be easily controlled by the polymerization conditions such as the irradiation amount of light (light amount).

The polymerization conversion rate of the ethylenically unsaturated compound in the above partial polymer is not particularly limited. From the viewpoint of ease of preparation and coatability of the pressure-sensitive adhesive composition, it is usually appropriate that the polymerization conversion rate is about 50% by weight or less, and about 40% by weight or less (for example, about 35% by weight or less). ) Is preferable. The lower limit of the polymerization conversion rate is not particularly limited, but is typically about 1% by weight or more, and usually about 5% by weight or more is appropriate.

The BP-type hybrid pressure-sensitive adhesive composition containing a partial polymer of an ethylenically unsaturated compound is, for example, a suitable polymerization method (for example, a monomer mixture containing the entire amount of the ethylenically unsaturated compound used for preparing the pressure-sensitive adhesive composition). It can be obtained by partial polymerization by a photopolymerization method). Further, the BP type hybrid pressure-sensitive adhesive composition containing a partial polymer of an ethylenically unsaturated compound is a partial polymer of a monomer mixture containing a part of the ethylenically unsaturated compound used in the preparation of the pressure-sensitive adhesive composition. And may be a mixture with the remaining ethylenically unsaturated compound or a partial polymer thereof. In the present specification, the term "complete polymer" means that the polymerization conversion rate is more than 95% by weight.

The partial polymer can be prepared, for example, by irradiating the ethylenically unsaturated compound with ultraviolet rays. When the above partial polymer is prepared in the presence of the BP polymer, the ethylenically unsaturated compound is partially reacted by reacting with the ethylenically unsaturated group and setting the irradiation conditions of ultraviolet rays so that the benzophenone structure is not photoexcited. A pressure-sensitive adhesive composition containing a polymer and a BP polymer can be obtained. As the light source, a light source such as the above-mentioned black light or UV-LED lamp that does not contain a component having a wavelength of less than 300 nm or can irradiate ultraviolet rays having a small wavelength component can be preferably adopted.

Further, after preparing a partial polymer of an ethylenically unsaturated compound in advance, the partial polymer and the BP polymer may be mixed to prepare a pressure-sensitive adhesive composition. When preparing a partial polymer of an ethylenically unsaturated compound by irradiating the ethylenically unsaturated compound with ultraviolet rays in the absence of a benzophenone structure-containing component, either a light source that does not excite the benzophenone structure or a light source that excites the benzophenone structure is used as the ultraviolet source. It is possible.

In preparing a partial polymer of an ethylenically unsaturated compound, the reaction of the ethylenically unsaturated group can be promoted by using a photopolymerization initiator. Examples of the photopolymerization initiator include a ketal-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, and an aromatic sulfonyl. Chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzyl-based photopolymerization initiator, benzophenone-based photopolymerization initiator, alkylphenone-based photopolymerization initiator, thioxanthone-based photopolymerization initiator Agents and the like can be used. A photopolymerization initiator that absorbs light having a wavelength of 300 nm or more (for example, light having a wavelength of 300 nm or more and 500 nm or less) to generate radicals can be preferably adopted. As the photopolymerization initiator, one type may be used alone or two or more types may be used in combination as appropriate.

The BP-type hybrid pressure-sensitive adhesive composition may contain a photopolymerization initiator, if necessary, for the purpose of improving or imparting photocurability. Examples of the photopolymerization initiator include a ketal-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, an α-ketol-based photopolymerization initiator, and an aromatic sulfonyl. Chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, benzyl-based photopolymerization initiator, benzophenone-based photopolymerization initiator, alkylphenone-based photopolymerization initiator, thioxanthone-based photopolymerization initiator Agents and the like can be used. As the photopolymerization initiator, one type may be used alone or two or more types may be used in combination as appropriate.

Specific examples of the ketal-based photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one and the like.
Specific examples of the acetophenone-based photopolymerization initiator include 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl]. -2-Hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, methoxyacetophenone and the like are included.
Specific examples of the benzoin ether-based photopolymerization initiator include benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether and benzoin isobutyl ether, and substituted benzoin ethers such as anisole methyl ether.
Specific examples of the acylphosphine oxide-based photopolymerization initiator include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -2,4-di-n-butoxy. Includes phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and the like.
Specific examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropane-1-one and the like. Is done.
Specific examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalene sulfonyl chloride and the like.
Specific examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime and the like.
Specific examples of the benzoin-based photopolymerization initiator include benzoin and the like.
Specific examples of the benzyl-based photopolymerization initiator include benzyl and the like.
Specific examples of the benzophenone-based photopolymerization initiator include benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone and the like.
Specific examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and isopropylthioxanthone. , 2,4-Diisopropylthioxanthone, dodecylthioxanthone and the like.

As the photopolymerization initiator contained in the BP-type hybrid pressure-sensitive adhesive composition, a photopolymerization initiator that absorbs light having a wavelength of 300 nm or more (for example, light having a wavelength of 300 nm or more and 500 nm or less) to generate radicals can be preferably adopted. As the photopolymerization initiator, one type may be used alone or two or more types may be used in combination as appropriate. In some embodiments, a photopolymerization initiator that does not contain a phosphorus element in the molecule can be preferably adopted. The BP-type hybrid pressure-sensitive adhesive composition may be substantially free of a photopolymerization initiator containing a phosphorus element in the molecule.

The content of the photopolymerization initiator in the BP-type hybrid pressure-sensitive adhesive composition is not particularly limited, and can be set so as to appropriately exert the desired effect. In some embodiments, the content of the photopolymerization initiator can be, for example, approximately 0.005 parts by weight or more with respect to 100 parts by weight of the monomer component constituting the BP type hybrid pressure-sensitive adhesive composition, and is usually used. It is appropriate to have 0.01 parts by weight or more, preferably 0.05 parts by weight or more, 0.10 parts by weight or more, 0.15 parts by weight or more, and 0.20 parts by weight. It may be more than a part. By increasing the content of the photopolymerization initiator, the photocurability of the BP type hybrid pressure-sensitive adhesive composition is improved. Further, the content of the photopolymerization initiator with respect to 100 parts by weight of the monomer component constituting the BP type hybrid pressure-sensitive adhesive composition is usually preferably 5 parts by weight or less, preferably 2 parts by weight or less. It may be 1 part by weight or less, 0.7 parts by weight or less, or 0.5 part by weight or less. It may be advantageous from the viewpoint of suppressing gelation of the BP-type hybrid pressure-sensitive adhesive composition that the content of the photopolymerization initiator is not too large.

The BP-type hybrid pressure-sensitive adhesive composition may include, for example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an oxazoline-based cross-linking agent, an aziridine-based cross-linking agent, a carbodiimide-based cross-linking agent, a melamine-based cross-linking agent, and a urea-based cross-linking agent, if necessary. Known cross-linking agents such as an agent, a metal alkoxide-based cross-linking agent, a metal chelate-based cross-linking agent, a metal salt-based cross-linking agent, a hydrazine-based cross-linking agent, and an amine-based cross-linking agent can be blended. Peroxide may be used as a cross-linking agent. These cross-linking agents may be used alone or in combination of two or more. The pressure-sensitive adhesive layer A formed from the BP-type hybrid pressure-sensitive adhesive composition containing a cross-linking agent preferably contains the cross-linking agent mainly in the form after the cross-linking reaction. By using the cross-linking agent, the cohesive force of the pressure-sensitive adhesive layer A can be appropriately adjusted.

The amount used when a cross-linking agent is used (when two or more kinds of cross-linking agents are used, the total amount thereof) is not particularly limited. From the viewpoint of realizing a pressure-sensitive adhesive that exhibits a well-balanced adhesive property such as adhesive force and cohesive force, the amount of the cross-linking agent used is 100 parts by weight and 100 parts by weight of the monomer component constituting the BP type hybrid pressure-sensitive adhesive composition. Usually, it is suitable to be about 5 parts by weight or less, may be 3 parts by weight or less, may be 1 part by weight or less, may be 0.50 parts by weight or less, and may be 0.30 parts by weight or less. , 0.20 parts by weight or less. The lower limit of the amount of the cross-linking agent used is not particularly limited, and may be more than 0 parts by weight with respect to 100 parts by weight of the monomer component constituting the BP type hybrid pressure-sensitive adhesive composition. In some embodiments, the amount of the cross-linking agent used may be, for example, 0.001 part by weight or more, and 0.01 part by weight or more, based on 100 parts by weight of the monomer component constituting the BP type hybrid pressure-sensitive adhesive composition. However, it may be 0.05 parts by weight or more, or 0.10 parts by weight or more.

The BP-type hybrid pressure-sensitive adhesive composition may contain various conventionally known chain transfer agents. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid, and α-thioglycerol can be used. Alternatively, a chain transfer agent containing no sulfur atom (non-sulfur chain transfer agent) may be used. Specific examples of the non-sulfur chain transfer agent include anilins such as N, N-dimethylaniline and N, N-diethylaniline; terpenoids such as α-pinene and turpinolene; α-methylstyrene and α-methylstyrene dimer. Stylines such as; compounds having a benzidenyl group such as dibenzylidene acetone, cinnamyl alcohol, cinnamyl aldehyde; hydroquinones such as hydroquinone and naphthohydroquinone; quinones such as benzoquinone and naphthoquinone; 2,3-dimethyl-2-butene , 1,5-Cyclooctadiene and other olefins; alcohols such as phenol, benzyl alcohol and allyl alcohol; benzyl hydrogens such as diphenylbenzene and triphenylbenzene; and the like. The chain transfer agent may be used alone or in combination of two or more. When a chain transfer agent is used, the amount used may be, for example, about 0.01 to 1 part by weight with respect to 100 parts by weight of the monomer component. It can also be preferably carried out in an embodiment in which a chain transfer agent is not used.

As another component that can be contained in the BP type hybrid pressure-sensitive adhesive composition, a silane coupling agent can be mentioned. The use of a silane coupling agent can improve the peel strength against an adherend (eg, a glass plate). Further, the pressure-sensitive adhesive layer A can contain a silane coupling agent. The pressure-sensitive adhesive layer A containing a silane coupling agent can be suitably formed by using a BP-type hybrid pressure-sensitive adhesive composition containing a silane coupling agent. The silane coupling agent may be used alone or in combination of two or more.

The BP-type hybrid pressure-sensitive adhesive composition includes, if necessary, a pressure-sensitive adhesive resin (for example, a rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based or other tack-imparting resin), a viscosity modifier (for example, a thickener). ), Various additives common in the field of adhesives such as leveling agents, antioxidants, plasticizers, fillers, stabilizers, preservatives, antioxidants, etc. may be included as other optional ingredients. As for such various additives, conventionally known additives can be used by a conventional method and do not particularly characterize the present invention, and therefore detailed description thereof will be omitted.

The BP-type hybrid pressure-sensitive adhesive composition can exhibit good adhesive strength without using the above-mentioned pressure-sensitive adhesive resin. Therefore, in some embodiments, the content of the tackifier resin in the pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition is, for example, less than 10 parts by weight, further less than 5 parts by weight, based on 100 parts by weight of the monomer component. can do. The content of the tackifier resin may be less than 1 part by weight (for example, less than 0.5 parts by weight) or less than 0.1 parts by weight (0 parts by weight or more and less than 0.1 parts by weight). good. The pressure-sensitive adhesive layer or the pressure-sensitive adhesive composition may not contain the pressure-sensitive adhesive resin.

By curing the BP-type hybrid pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer A containing a BP polymer (hereinafter, may be referred to as “BP-type pressure-sensitive adhesive layer A”) can be formed. Curing of the BP-type hybrid pressure-sensitive adhesive composition is carried out so as to react the ethylenically unsaturated group contained in the pressure-sensitive adhesive composition and leave the benzophenone structure contained in the BP-type hybrid pressure-sensitive adhesive composition. Is preferable. The curing can be preferably performed by irradiation with active energy rays. As the active energy ray for forming the pressure-sensitive adhesive layer A, ultraviolet rays are preferable, and ultraviolet rays containing no component having a wavelength of less than 300 nm or having a small wavelength component are more preferable.

The BP-type pressure-sensitive adhesive layer A is produced by using the BP-type hybrid pressure-sensitive adhesive composition. The BP-type pressure-sensitive adhesive layer A may contain a BP polymer and a polymer derived from an ethylenically unsaturated compound. In some preferred embodiments, the BP-type hybrid pressure-sensitive adhesive composition may be such that the ethylenically unsaturated compound does not contain ethylenically unsaturated BP. According to the BP type hybrid pressure-sensitive adhesive composition having such a composition, a BP type pressure-sensitive adhesive layer A containing a BP polymer and a polymer derived from an ethylenically unsaturated compound, wherein the polymer is a non-BP polymer is produced. obtain.

The method for producing the BP-type pressure-sensitive adhesive layer A from the BP-type hybrid pressure-sensitive adhesive composition is a method for producing the BP-type pressure-sensitive adhesive layer A in place of the base polymer in the pressure-sensitive adhesive layer forming step and the pressure-sensitive adhesive layer curing step in the above-mentioned second embodiment. It can be carried out by a method using a pressure-sensitive adhesive composition.
The curing conditions in the pressure-sensitive adhesive layer curing step of the present embodiment include components having a wavelength of less than 300 nm, such as a black light and a UV-LED lamp, in order to react the above-mentioned ethylenically unsaturated group and leave the benzophenone structure. A light source capable of irradiating ultraviolet rays that do not contain or have a small wavelength component can be preferably adopted.

<Self-luminous display device>
In the self-luminous display device according to the second aspect of the present invention, a small and large number of light emitting elements are arranged on a wiring substrate, and each light emitting element is selectively emitted by a light emitting control means connected thereto. , A display device capable of displaying visual information such as characters, images, and moving images directly on a display screen by blinking each light emitting element. Examples of the self-luminous display device include a mini / micro LED display device and an organic EL (electroluminescence) display device. The photocurable pressure-sensitive adhesive sheet A according to the first aspect of the present invention is particularly preferably used for manufacturing a mini / micro LED display device.

FIG. 4 is a schematic view (cross-sectional view) showing an embodiment of a self-luminous display device (mini / micro LED display device) on the second side surface of the present invention.
In FIG. 4, the mini / micro LED display device 2A has a display panel in which a plurality of LED chips 23 are arranged via a metal wiring layer 22 on one side of a substrate 21, and is laminated on the display panel to form a metal wiring layer 22. It is composed of a pressure-sensitive adhesive layer 20 for sealing a plurality of LED chips 23 and a cover member 24 laminated on the upper portion (image display side) of the pressure-sensitive adhesive layer 20. The cover member 24 is not particularly limited, but can be made of the same material as the above-mentioned "base material".

In the mini / micro LED display device 2A of the present embodiment, a metal wiring layer 22 for sending a light emission control signal to each LED chip 23 is laminated on the substrate 21 of the display panel. The LED chips 23 that emit light of each color of red (R), green (G), and blue (B) are alternately arranged on the substrate 21 of the display panel via the metal wiring layer 22. The metal wiring layer 22 is made of a metal such as copper, and reflects the light emitted from each LED chip 23 to reduce the visibility of the image. Further, the light emitted from each LED chip 23 of each color of RGB is mixed, and the contrast is lowered.

In the mini / micro LED display device 2A of the present embodiment, each LED chip 23 arranged on the display panel is sealed by the adhesive layer 20. The pressure-sensitive adhesive layer 20 is composed of a cured product of the pressure-sensitive adhesive layer A of the present invention. The pressure-sensitive adhesive layer 20 sufficiently follows the minute steps between the plurality of LED chips 23 and is sealed without gaps.

The pressure-sensitive adhesive layer 20 has sufficient light-shielding properties in the visible light region. Since the fine step between the LED chips 23 is sealed without gaps by the adhesive layer 20 having a high light-shielding property, it is possible to prevent reflection by the metal wiring layer 22 and prevent color mixing between the LED chips 23. And the contrast can be improved.

Further, since the pressure-sensitive adhesive layer 20 is a cured product of the pressure-sensitive adhesive layer A, it is excellent in processability. Therefore, the adhesive chipping during the cutting process of the mini / micro LED display device 2A of the present embodiment, and the protrusion and sagging of the adhesive layer 20 from the end portion during storage are suppressed.

The self-luminous display device (mini / micro LED display device) of the present embodiment may include an optical member other than the display panel, the adhesive layer, and the cover member. The optical member is not particularly limited, and examples thereof include a polarizing plate, a retardation plate, an antireflection film, a viewing angle adjusting film, and an optical compensation film. The optical member shall also include a member (design film, decorative film, surface protective plate, etc.) that plays a role of decoration and protection while maintaining the visibility of the display device and the input device.

The self-luminous display device (mini / micro LED display device) of the present embodiment is not particularly limited, but can be preferably manufactured by a method including the following steps.
(1) A step of laminating the pressure-sensitive adhesive layer A of the photocurable pressure-sensitive adhesive sheet A on a display panel in which a plurality of light-emitting elements are arranged on one side of a substrate, and sealing the light-emitting element with the pressure-sensitive adhesive layer A.
(2) A step of irradiating the pressure-sensitive adhesive layer with radiation to cure it.

FIG. 5 is a diagram schematically showing a process for carrying out one embodiment of a method for manufacturing a self-luminous display device (mini / micro LED display device) according to the second aspect of the present invention. In the present embodiment, as shown in FIG. 5A, a plurality of light emitting elements (1E) on the second side surface of the present invention and a plurality of light emitting elements (on one side of the substrate 21) via the metal wiring layer 22. A display panel in which the LED chips) 23 are arranged is used.

In the present embodiment, the photocurable pressure-sensitive adhesive sheet 1E is composed of a pressure-sensitive adhesive layer 10 and a cover member 24 that can be manufactured by the method for producing the photo-curable pressure-sensitive adhesive sheet A according to the second embodiment of the present invention. The pressure-sensitive adhesive layer 10 has a structure in which the cross-linking agent 11 and the photopolymerization initiator 12 are dissolved in the base polymer. The embodiment in which only one of the cross-linking agent 11 and the photopolymerization initiator 12 is dissolved in the pressure-sensitive adhesive layer 10 is also included in the present embodiment. In this embodiment, there is a concentration gradient of the cross-linking agent 11 and the photopolymerization initiator 12 in the thickness direction from the main surface 10A where the pressure-sensitive adhesive layer 10 is in contact with the support S3.

In this embodiment, the photocurable pressure-sensitive adhesive sheet 1E has a cover member 24, but the cover member 24 may not be present. The cover member 24 is not particularly limited, but may be made of the same material as the above-mentioned "base material", and may be a release film (separator).

Next, as shown in FIG. 5B, the main surface 10B on which the cover member 24 of the adhesive layer 10 of the photocurable adhesive sheet 1E is not laminated is laminated on the surface of the display panel in which a plurality of LEDs are arranged. Then, the LED chip 23 and the metal wiring layer 22 are sealed with the adhesive layer 10. The lamination can be carried out by a known method, for example, under heating and pressurizing conditions using an autoclave. The pressure-sensitive adhesive layer 10 of the photocurable pressure-sensitive adhesive sheet 1E has high fluidity and exhibits excellent step absorption. Therefore, the pressure-sensitive adhesive layer 10 is sealed so as to fill the step between the metal wiring layer 22 and the plurality of LED chips 23 without gaps.

Next, as shown in FIG. 5C, the pressure-sensitive adhesive layer 10 is irradiated with radiation to cure it. Upon irradiation with radiation, the photopolymerization initiator 12 is decomposed to generate radicals or ions, and the polymerization / cross-linking reaction of the cross-linking agent 12 is started. The radiation is not particularly limited as long as the pressure-sensitive adhesive layer 10 is cured, but ultraviolet rays in which the pressure-sensitive adhesive layer 10 exhibits transparency are preferable. That is, since the pressure-sensitive adhesive layer 10 has a high light-shielding property against visible light and a high transparency against ultraviolet rays, the pressure-sensitive adhesive layer 10 can be cured by the ultraviolet rays. FIG. 5C is an embodiment in which the pressure-sensitive adhesive layer 10 is irradiated with ultraviolet rays U to be cured.

The ultraviolet rays are preferably ultraviolet rays having a wavelength of 200 to 400 nm, and more preferably ultraviolet rays having a wavelength of 330 to 400 nm. When the pressure-sensitive adhesive layer 10 is composed of the BP-type pressure-sensitive adhesive layer A, the benzophenone structure can be cured by irradiating with ultraviolet rays containing an excitable wavelength component, and specifically, the wavelength is less than 300 nm. It is preferable to use a light source capable of irradiating ultraviolet rays containing the above components.

As the light source for irradiating ultraviolet rays, for example, a high-pressure mercury lamp, a low-pressure mercury lamp, a microwave-excited lamp, a metal halide lamp, a chemical lamp, a black light, or an LED can be used. Further, regarding the irradiation time and irradiation method of ultraviolet rays, as long as the adhesive layer 10 can be cured and the display panel is not unduly affected, and the adhesive layer 10 is cured and exhibits sufficient processability, it is appropriate. Can be set. For example, the irradiation amount (integrated light amount) of ultraviolet rays is preferably 1000 mJ / cm ² to 10000 mJ / cm ² , more preferably 2000 mJ / cm ² to 4000 mJ / cm ² , and further preferably 3000 mJ / cm ² . ..

By curing the pressure-sensitive adhesive layer 10, a self-luminous display device (mini / micro LED display device) 2B can be obtained as shown in FIG. 5 (d). In FIG. 5D, the pressure-sensitive adhesive layer 20 is a pressure-sensitive adhesive layer in which the pressure-sensitive adhesive layer 10 is cured. The self-luminous display device (mini / micro LED display device) 2B is an embodiment showing an example of the self-luminous display device (mini / micro LED display device) on the second side surface of the present invention.

By curing the pressure-sensitive adhesive layer 10, the cross-linking agent 11 is cross-linked and polymerized to form a cross-linked structure 11'to form the pressure-sensitive adhesive layer 20. The pressure-sensitive adhesive layer 20 has improved workability, and it is possible to prevent adhesive chipping during cutting processing and protrusion and sagging of the pressure-sensitive adhesive layer from the end portion during storage. Further, the pressure-sensitive adhesive layer 20 suppresses the generation of gas such as carbon dioxide due to the heating of the display panel, can prevent the generation of bubbles, and improves the adhesive reliability.

Further, in the embodiment of FIG. 5D, the cross-linking density is higher on the side of the main surface where the pressure-sensitive adhesive layer 20 is in contact with the support S3 than on the main surface on the opposite side. This configuration is preferable because, for example, when the self-luminous display device (mini / micro LED display device) is used as a flexible image display device that bends outward, the flexibility can be improved.
That is, when the flexible display is bent, a tensile stress is generally applied to the outside and a compressive stress is applied to the inside, and the stress on the outside is stronger than the stress on the inside. Therefore, by arranging the upper portion (painter display side) of the pressure-sensitive adhesive layer 20 on the outside when the flexible display is bent, the durability against bending can be improved.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[Example 1]
(Preparation of prepolymer)
In a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 67 parts by weight of butyl acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA) and 4-hydroxybutyl acrylate (4) were added as monomer components. -HBA) 19 parts by weight, photopolymerization initiator (BASF, trade name "Irgacure 184") 0.09 parts by weight, and photopolymerization initiator (BASF, trade name "Irgacure 651") 0.09 weight After charging the parts, nitrogen gas was flowed and nitrogen substitution was performed for about 1 hour while stirring. Then, UVA was irradiated at 5 mW / cm ² to carry out polymerization, and the reaction rate was adjusted to 5 to 15% to obtain an acrylic prepolymer solution A.

(Preparation of adhesive composition)
In the acrylic prepolymer solution A obtained above (the total amount of the prepolymer is 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA), As a polyfunctional monomer, dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Kogyo Kagaku Co., Ltd., trade name "KAYARAD DPHA") 0.02 part by weight, silane coupling agent (3-glycidoxypropyltrimethoxysilane, manufactured by Shinetsu Kagaku Kogyo Co., Ltd.) , Trade name "KBM-403") 0.35 part by weight and a photopolymerization initiator (BASF, "Irgacure 651") 0.45 part by weight were added to obtain a pressure-sensitive adhesive composition B.

(Preparation of black adhesive composition)
To 100 parts by weight of the pressure-sensitive adhesive composition B, 5.8 parts by weight of a 20% dispersion of black pigment (“9256BLACK” manufactured by Tokushiki) and 0.2 weight by 0.2 weight of an additional photopolymerization initiator (“Irgacure 651” manufactured by BASF). Part was added to obtain a black pressure-sensitive adhesive composition C.

(Making an adhesive sheet)
The black pressure-sensitive adhesive composition C prepared above is applied to the peeling surface of a release film R1 (MRF # 38, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm in which one side of the polyester film is a peeling surface, and one side of the polyester film is applied. Was covered with a release film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.) having a release surface to block air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name FL15BL) under the conditions of an illuminance of 5 mW / cm ² and an integrated light amount of 1300 mJ / cm ² . As a result, a pressure-sensitive adhesive sheet D having a thickness of about 50 μm, which is a cured product of the black pressure-sensitive adhesive composition C, sandwiched between the release films R1 and R2 was obtained in the form of a base-less double-sided pressure-sensitive adhesive sheet.
The illuminance value of the black light is a measured value by an industrial UV checker (manufactured by Topcon, trade name: UVR-T1, light receiving unit model UD-T36) having a peak sensitivity wavelength of about 350 nm.

(Preparation of photocurable adhesive sheet)
A solution obtained by peeling off the release film R2 of the pressure-sensitive adhesive sheet D and dissolving it in trimethylolpropane triacrylate (TMPTA) so that the photopolymerization initiator (trade name "Irgacure 651" manufactured by BASF) is 5% by weight is used. , RD Specialties' Wire Wound Rod type, # 7 bar coater was used for coating (target Wet coating thickness 15 μm). After application, it was heated in an oven at 110 ° C. for 2 minutes. Then, the pressure-sensitive adhesive surface was protected again with the release film R2, and a photocurable pressure-sensitive adhesive sheet E containing a pressure-sensitive adhesive layer in which TMPTA and a photopolymerization initiator were dissolved was obtained in the form of a substrate-less double-sided pressure-sensitive adhesive sheet.

[Example 2]
(Preparation of solvent-type black pressure-sensitive adhesive composition)
In a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube, 60 parts by weight of n-butyl acrylate (BA), 6 parts by weight of cyclohexyl acrylate (CHA) and N-vinyl-2- 18 parts by weight of pyrrolidone (NVP), 1 part by weight of isostearyl acrylate (iSTA), 15 parts by weight of 4-hydroxybutyl acrylate (4HBA), 0.125 parts by weight of α-thioglycerol as a chain transfer agent, and ethyl acetate as a polymerization solvent. Mw is about 500,000 by charging 122 parts by weight, adding 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and performing solution polymerization in a nitrogen atmosphere. A solution containing the acrylic polymer of the above was obtained.

In the solution obtained above, 0.22 parts by weight of a polymerization initiator (BASF, "Irgacure 651") and an isocyanate-based cross-linking agent (trimethylolpropane / xylyl) per 100 parts of the monomer component used for preparing the solution. Range isocyanate adduct, manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-110N", solid content concentration 75%) in 0.27 parts by weight based on solid content, dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Kogyo Kagaku, trade name) "KAYARAD DPHA") 2.2 parts by weight, polypropylene glycol # 400 diacrylate (manufactured by Shin-Nakamura Kogyo Kagaku) 1 part by weight, silane coupling agent (3-glycidoxypropyltrimethoxysilane, manufactured by Shinetsu Kagaku Kogyo Co., Ltd., Product name "KBM-403") 0.33 parts by weight, antioxidant (manufactured by BASF, product name "IRGANOX1135") 0.3 parts by weight, polyether polyol (manufactured by ADEKA, product name "Adecapolyether EPD-300") ]) 0.18 parts by weight and 4 parts by weight of a 20% dispersion of black pigment (“9170BLACK” manufactured by Tokushiki) were added to obtain a solvent-type black pressure-sensitive adhesive composition.

(Preparation of photocurable adhesive sheet)
Two release films (MRF # 38, manufactured by Mitsubishi Plastics) having a thickness of 38 μm in which one side of the polyester film is a release surface were prepared. The solvent-based black pressure-sensitive adhesive composition prepared above was applied to the peeled surface of the first release film and dried at 60 ° C. for 3 minutes and then at 120 ° C. for 3 minutes to achieve a photocurable pressure-sensitive adhesive having a thickness of 134 μm. An agent layer was formed. The peeling surface of the second release film was attached to and protected from this pressure-sensitive adhesive layer to obtain a photocurable pressure-sensitive adhesive sheet in the form of a base-less double-sided pressure-sensitive adhesive sheet.

[Example 3]
(Preparation of adhesive composition)
An acrylic copolymer having a benzophenone structure on the side chain in a separable flask equipped with a thermometer, a stirrer, a reflux cooling tube and a nitrogen gas introduction tube (manufactured by BASF, trade name "acResin A260UV", Tg: -39 ° C. , Mw: 19 × 104, BP equivalent: ² mg / g) 50 parts by weight, butyl acrylate (BA) 26 parts by weight, N-vinyl-2-pyrrolidone (NVP) 8 parts by weight, isobornyl acrylate (IBXA) 16 A pressure-sensitive adhesive composition was prepared by charging 0.2 parts by weight and 0.2 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 184") and mixing them.

(Preparation of black adhesive composition)
A black pressure-sensitive adhesive composition was prepared by adding 2 parts by weight of a 20% dispersion of a black pigment (“9256BLACK” manufactured by Tokushiki) to 100 parts by weight of the pressure-sensitive adhesive composition.

(Preparation of photocurable adhesive sheet)
The black pressure-sensitive adhesive composition prepared above is applied to the peeling surface of a release film R1 (MRF # 38, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm in which one side of the polyester film is a peeling surface, and one side of the polyester film is formed. The peeling film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.), which is the peeling surface, was covered to shut off the air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name FL15BL) under the conditions of an illuminance of 5 mW / cm ² and an integrated light amount of 1300 mJ / cm ² . As a result, a photocurable pressure-sensitive adhesive sheet in which a pressure-sensitive adhesive layer having a thickness of about 104 μm, which is a cured product of the black pressure-sensitive adhesive composition, was sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less double-sided pressure-sensitive adhesive sheet. ..

[Example 4]
(Preparation of black adhesive composition)
In 100 parts by weight of the pressure-sensitive adhesive composition B prepared in Example 1, 4 parts by weight of a 20% dispersion of a black pigment (“9256BLACK” manufactured by Tokushiki) and an additional photopolymerization initiator (“Irgacure 651” manufactured by BASF) 0. 2 parts by weight and 1 part of 4-acryloyloxybenzophenone manufactured by Ark Polymer were added to obtain a black pressure-sensitive adhesive composition.

(Preparation of photocurable adhesive sheet)
The black pressure-sensitive adhesive composition prepared above is applied to the peeling surface of a release film R1 (MRF # 38, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm in which one side of the polyester film is a peeling surface, and one side of the polyester film is formed. The peeling film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.), which is the peeling surface, was covered to shut off the air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name FL15BL) under the conditions of an illuminance of 5 mW / cm ² and an integrated light amount of 1300 mJ / cm ² . As a result, a pressure-sensitive adhesive sheet having a thickness of about 100 μm, which is a cured product of the black pressure-sensitive adhesive composition, sandwiched between the release films R1 and R2 was obtained in the form of a base-less double-sided pressure-sensitive adhesive sheet.
The illuminance value of the black light is a measured value by an industrial UV checker (manufactured by Topcon, trade name: UVR-T1, light receiving unit model UD-T36) having a peak sensitivity wavelength of about 350 nm.

[Example 5]
A photocurable pressure-sensitive adhesive sheet was prepared in the same manner as in Example 4 except that 4-acryloyloxybenzophenone was added to two parts.

[Reference Example 1]
(Preparation of adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) are added to the acrylic prepolymer solution A (the total amount of the prepolymer is 100 parts by weight) obtained in Example 1. A pressure-sensitive adhesive composition was obtained by adding 0.45 parts by weight of a polymerization initiator (BASF, "Irgacure 651") and 1 part by weight of nanosilica (Nippon Aerodil, trade name "R976S"). ..

(Preparation of black adhesive composition)
To 100 parts by weight of the pressure-sensitive adhesive composition, 5.8 parts by weight of a 20% dispersion of black pigment (“9256BLACK” manufactured by Tokushiki) and 0.2 weight by 0.2 weight of an additional photopolymerization initiator (“Irgacure 651” manufactured by BASF). Parts were added to obtain a black pressure-sensitive adhesive composition.

(Making an adhesive sheet)
The black pressure-sensitive adhesive composition prepared above is applied to the peeling surface of a release film R1 (MRF # 38, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm in which one side of the polyester film is a peeling surface, and one side of the polyester film is formed. The peeling film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.), which is the peeling surface, was covered to shut off the air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name FL15BL) under the conditions of an illuminance of 5 mW / cm ² and an integrated light amount of 1300 mJ / cm ² . As a result, a pressure-sensitive adhesive layer having a thickness of about 100 μm, which is a cured product of the black pressure-sensitive adhesive composition, was sandwiched between the release films R1 and R2, and a base-less double-sided pressure-sensitive adhesive sheet was obtained. The obtained adhesive sheet does not show photocurability.

[Reference Example 2]
An adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nanosilica used was 3 parts by weight.

[Reference Example 3]
An adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nanosilica used was 5 parts by weight.

[Reference example 4]
An adhesive sheet was obtained in the same manner as in Reference Example 1 except that the amount of nanosilica used was 7 parts by weight.
In Reference Examples 1 to 4, in order to verify the storage elastic modulus and its ratio for achieving both step followability and workability, a pressure-sensitive adhesive sheet that does not show photocurability is used and the storage elastic modulus is determined by the amount of nanosilica used. The purpose is to change and evaluate.

[Comparative Example 1]
(Making an adhesive sheet)
The pressure-sensitive adhesive composition B prepared in Example 1 is applied to the peeling surface of a release film R1 (MRF # 38, manufactured by Mitsubishi Resin Co., Ltd.) having a thickness of 38 μm in which one side of the polyester film is a peeling surface, and the polyester film is coated. The air was shut off by covering with a release film R2 (MRE # 38 manufactured by Mitsubishi Resin Co., Ltd.) having one side as a release surface. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name FL15BL) under the conditions of an illuminance of 5 mW / cm ² and an integrated light amount of 1300 mJ / cm ² . As a result, a pressure-sensitive adhesive sheet having a thickness of about 50 μm, which is a cured product of the pressure-sensitive adhesive composition B, sandwiched between the release films R1 and R2 was obtained in the form of a base-less double-sided pressure-sensitive adhesive sheet.

(Preparation of photocurable adhesive sheet)
A solution obtained by peeling off the release film R2 of the pressure-sensitive adhesive sheet and dissolving it in trimethylolpropane triacrylate (TMPTA) so that the photopolymerization initiator (trade name "Irgacure 651" manufactured by BASF) is 5% by weight is prepared. It was coated with a Wild Wound Rod type # 7 bar coater manufactured by RD Specialties (target Wet coating thickness 15 μm). After application, it was heated in an oven at 110 ° C. for 2 minutes. Then, the pressure-sensitive adhesive surface was protected again with the release film R2, and a photocurable pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer in which TMPTA and a photopolymerization initiator were dissolved was obtained in the form of a substrate-less double-sided pressure-sensitive adhesive sheet.

[Comparative Example 2]
The adhesive sheet D obtained in Example 1 was used as the adhesive sheet of Comparative Example 2. The pressure-sensitive adhesive sheet D does not show photocurability.

(evaluation)
The following evaluations were performed using the adhesive sheets obtained in the above Examples, Reference Examples, and Comparative Examples. The evaluation method is shown below. The results are shown in Table 1.

[Evaluation of transmittance]
The release film on one side was peeled off from the adhesive sheet, and non-alkali glass was attached to the exposed surface. Then, the release film on the other surface was peeled off from the pressure-sensitive adhesive sheet to obtain a sample in which the pressure-sensitive adhesive sheet was bonded on a non-alkali glass plate.
The total light transmittance was measured using a haze meter (manufactured by Murakami Color Science Laboratory Co., Ltd., trade name "HN-150") by the method specified by JIS K7361.

[Evaluation of storage elastic modulus]
Evaluation was performed using ARES GII manufactured by TA Instruments.
An adhesive sheet laminated to a thickness of about 1 mm was sandwiched between 8 mm parallel plates, and measured at an initial strain of 1%, a frequency of 1 Hz, and a heating rate of 5 ° C / min from -50 ° C to 100 ° C. The storage elastic modulus G'at 25 ° C. and 85 ° C. was read and used as the storage elastic modulus G'(G'b10, G'b25, G'b85) before curing.
Regarding the storage elastic modulus G'after curing, a high-pressure mercury lamp irradiated with a high-pressure mercury lamp so as to have an integrated light amount of 3000 mJ / cm ² is laminated on an adhesive sheet sandwiched between release films so as to have a thickness of about 1 mm. Then, it was evaluated in the same manner as above, and the storage elastic modulus after curing was G'(G'a10, G'a25, G'a85).
This integrated light quantity is a measured value by an industrial UV checker (manufactured by Topcon, trade name: UVR-T1, light receiving unit model UD-T36) having a peak sensitivity wavelength of about 350 nm.
Since the pressure-sensitive adhesive sheets of Reference Examples 1 to 4 and Comparative Example 2 do not show photocurability, the storage elastic modulus G'after curing has not been evaluated.

[Evaluation of step followability]
(Making uneven adherend)
After laminating a laminate of TAC film (thickness 60 μm) and adhesive (thickness 20 μm) on a glass plate of 45 mm × 50 mm, a CO ₂ laser (wavelength 10.6 μm, laser diameter 〇 μm) is used to central 10 mm ×. By performing linear etching processing within a range of 10 mm at a pitch of 150 μm in the vertical direction and a pitch of 225 μm in the horizontal direction, an adherend A in which the TAC film and the pressure-sensitive adhesive layer were processed into a grid-like uneven shape was obtained.
The adherend A imitates an LED panel in which a plurality of LED films are arranged on a substrate.
(Making an adhesive sheet)
The pressure-sensitive adhesive sheets prepared in Examples 1 and 3, Reference Examples 1 to 4, and Comparative Examples 1 and 2 were laminated to have a thickness of about 200 μm. The pressure-sensitive adhesive sheets prepared in Example 2 were laminated to make about 250 μm. The release film on one surface of these laminated pressure-sensitive adhesive sheets was peeled off, and a PET film having a thickness of 75 μm was attached to the exposed surface.
(Vacuum bonding)
The adhesive surface exposed by peeling off the other release film of the laminated adhesive sheet obtained above and the processed surface of the adherend A are adhered using a vacuum bonding device (SE340aaH manufactured by CRIMB Products). The processing range of the body A was bonded with an accuracy that allows the pressure-sensitive adhesive sheet to be completely covered, and an evaluation sample consisting of a PET film, a laminated pressure-sensitive adhesive sheet, and an adherend A was obtained. Further, they were brought into close contact by autoclaving (60 minutes under the conditions of 50 ° C. and 0.5 MPa).
(Evaluation of step followability)
In the above evaluation sample, when the adhesive sheet can follow the uneven pattern portion, the processed portion of the adherend A is visually recognized transparently, and the portion that cannot be followed is visually recognized as white. The area of the white part was calculated by shooting with a fixed point camera to evaluate the step followability.

Step followability (%) = 100- {[Area of white part at the time of evaluation] / [Area of white part before bonding = 1 cm ² ] × 100}

[Evaluation of workability]
(Manufacturing of laminated products for workability evaluation)
The release film of the laminated adhesive sheet produced in the section of evaluation of step followability was peeled off and bonded to a fr-4 substrate (thickness 1.2 mm) manufactured by Misumi Corporation. After autoclaving (15 minutes under the conditions of 50 ° C. and 0.5 MPa), the photocurable Examples 1 to 3 and Comparative Example 1 were irradiated with ultraviolet rays. The ultraviolet irradiation conditions were a high-pressure mercury lamp and an integrated light intensity of 3000 mJ / cm ² . The integrated light quantity is a value measured by an industrial UV checker (manufactured by Topcon, trade name: UVR-T1, light receiving unit model UD-T36) having a peak sensitivity wavelength of about 350 nm.
(processing)
Using DTF6450 manufactured by Disco Corporation, the laminate for evaluation of processability obtained above was cut. The cutting conditions were blade type P1A861 (abrasive grain # 400 count), spindle 30 kHz, speed 30 mm / s, and cooling water 1 L / min.
(Evaluation of workability)
The cut end portion was observed from the laminated adhesive sheet side with a stereomicroscope, and the processability was evaluated by the amount of glue squeezed out from the cut end portion. The evaluation criteria are as follows.
◯: 0 to 150 μm
Δ: 150 to 200 μm
×: 200 μm or more

[Evaluation of reflectance]
An aluminum foil was attached to a black acrylic plate to prepare a laminated plate. The release film on one surface of the pressure-sensitive adhesive sheets produced in Examples 1 to 3 and Comparative Examples 1 and 2 was peeled off, and a PET film having a thickness of 75 μm was attached to the exposed surface. The adhesive surface exposed by peeling off the other release film was laminated on the aluminum foil side of the plate to prepare a sample. The obtained sample was placed on a spectrophotometer U4100 (manufactured by Hitachi High-Technology Co., Ltd.) with a PET film on the light source side, and the reflectance (%) in the visible light region of 5 ° specular reflection was measured.

Examples 1 to 5, which are photocurable pressure-sensitive adhesive sheets, showed excellent step-following property (step-absorbing property) and processability. From Reference Examples 1 to 4 and Comparative Example 2, it can be seen that if the storage elastic modulus at 85 ° C. before curing is less than 65 kPa, the step followability (step absorption) is improved. Further, according to Reference Examples 1 to 4, the storage elastic modulus (G'b85) at 85 ° C. before curing is less than 65 kPa, and the storage elastic modulus (G'b85) at 85 ° C. before curing is 10 ° C. after curing. It can be seen that in the region where the ratio (G'a10 / G'b85) of the storage elastic modulus (G'a10) exceeds 3.3, excellent step followability (step absorption) and workability are exhibited. Since the adhesive sheets of Reference Examples 1 to 4 do not show photocurability, the ratio of the storage elastic modulus (G'b10) at 10 ° C. before curing to the storage elastic modulus (G'b85) at 85 ° C. before curing. It was evaluated using (G'b10 / G'b85).
Comparative Example 1, which is a photocurable pressure-sensitive adhesive sheet, showed excellent step-following property (step-absorbing property) and processability, but had high reflectance because it did not contain a black pigment.

Variations of the present invention are described below.
[Appendix 1] A pressure-sensitive adhesive layer that is cured by irradiation is included.
The pressure-sensitive adhesive layer contains a colorant and contains
In the pressure-sensitive adhesive layer, the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm.
The storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer at 85 ° C. before curing is less than 65 kPa.
The storage elastic modulus (G'a10) of the pressure-sensitive adhesive layer after curing at 10 ° C. and the storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer at 85 ° C. before curing satisfy the following relational expression (1). , Photo-curing adhesive sheet.
3.3 <G'a10 / G'b85 (1)
[Appendix 2] The photocurable pressure-sensitive adhesive sheet according to Appendix 1, wherein the colorant is a colorant in which the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm.
[Appendix 3] The photocurable pressure-sensitive adhesive sheet according to Appendix 1 or 2, wherein the curing by irradiation with radiation is curing by irradiation with ultraviolet rays having a cumulative light amount of 3000 mJ / cm ² .
[Appendix 4] The photocurable pressure-sensitive adhesive sheet according to any one of Supplementary note 1 to 3, wherein the cured adhesive layer has a storage elastic modulus (G'a10) at 10 ° C. of 90 kPa or more.
[Appendix 5] The photocurable pressure-sensitive adhesive sheet according to any one of Supplementary note 1 to 4, wherein the pressure-sensitive adhesive layer contains a base polymer, a cross-linking agent, and a photopolymerization initiator.
[Appendix 6] The photocurable pressure-sensitive adhesive sheet according to Appendix 5, wherein the base polymer contains an acrylic polymer.
[Appendix 7] The photocurable pressure-sensitive adhesive sheet according to Appendix 5 or 6, wherein the cross-linking agent contains a polyfunctional (meth) acrylate.
[Appendix 8] The pressure-sensitive adhesive layer is a single layer made of the base polymer and having two opposing main surfaces.
Concentration of the cross-linking agent and / or the photopolymerization initiator in the region to which the first main surface of one of the two main surfaces belongs when the pressure-sensitive adhesive layer of the single layer is divided into two equal parts in the thickness direction. The photocurable pressure-sensitive adhesive sheet according to any one of Supplementary note 5 to 7, wherein the cross-linking agent and / or the photopolymerization initiator has different concentrations in the region to which the other second main surface belongs.
[Appendix 9] The photocurable pressure-sensitive adhesive sheet according to Appendix 8, wherein the single-layer pressure-sensitive adhesive layer has a concentration gradient of the cross-linking agent and / or the photopolymerization initiator in the thickness direction.
[Appendix 10] A single pressure-sensitive adhesive layer formed by the base polymer is formed.
The pressure-sensitive adhesive layer is cured and
Prepare a solution of the cross-linking agent and / or the photopolymerization initiator.
The solution is applied to one surface of the cured pressure-sensitive adhesive layer, and the cross-linking agent and / or the photopolymerization initiator contained in the solution permeates from the one surface of the pressure-sensitive adhesive layer in the thickness direction. Let me
The method for producing a photocurable pressure-sensitive adhesive sheet according to Appendix 8 or 9, which comprises a step of drying the pressure-sensitive adhesive layer.
[Appendix 11] The photocurable pressure-sensitive adhesive sheet according to any one of Supplementary note 1 to 4, wherein the pressure-sensitive adhesive layer contains a polymer having a benzophenone structure in a side chain.
[Appendix 12] The photocurable pressure-sensitive adhesive sheet according to Appendix 11, wherein the pressure-sensitive adhesive layer is a cured product of a pressure-sensitive adhesive composition containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain.
[Appendix 13] A display panel in which a plurality of light emitting elements are arranged on one side of a substrate, and
A self-luminous display device comprising the photocurable pressure-sensitive adhesive sheet according to any one of Supplementary Notes 1 to 9, 11 and 12.
The light emitting element of the display panel is sealed with the pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive sheet.
A self-luminous display device in which the adhesive layer is cured.
[Appendix 14] The self-luminous display device according to Annex 13, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.
[Appendix 15] The pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive sheet according to any one of Supplementary Notes 1 to 9, 11 and 12 is laminated on a display panel in which a plurality of light emitting elements are arranged on one side of a substrate. The method for manufacturing a self-luminous display device according to Appendix 13 or 14, comprising a step of sealing the light emitting element with a pressure-sensitive adhesive layer and a step of irradiating the pressure-sensitive adhesive layer with radiation to cure the light-emitting element.
[Appendix 16] The production method according to Annex 15, wherein the radiation is ultraviolet rays.

1A-1E Photocurable adhesive sheet 10 Adhesive layer 10a-10c Adhesive layer 11 Cross-linking agent 12 Photopolymerization initiator 13 Solvent 14 Solution 2A, 2B Self-luminous display device (mini / micro LED display device)
20 Adhesive layer 21 Substrate 22 Metal wiring layer 23 Light emitting element (LED chip)
24 Cover members S1, S2 Support (release film)

Claims (16)

Contains an adhesive layer that cures with irradiation
The pressure-sensitive adhesive layer contains a colorant and contains
In the pressure-sensitive adhesive layer, the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm.
The storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer at 85 ° C. before curing is less than 65 kPa.
The storage elastic modulus (G'a10) of the pressure-sensitive adhesive layer after curing at 10 ° C. and the storage elastic modulus (G'b85) of the pressure-sensitive adhesive layer at 85 ° C. before curing satisfy the following relational expression (1). , Photo-curable adhesive sheet.
3.3 <G'a10 / G'b85 (1) The photocurable pressure-sensitive adhesive sheet according to claim 1, wherein the colorant is a colorant in which the maximum value of the transmittance at a wavelength of 200 to 400 nm is larger than the maximum value of the transmittance at a wavelength of 400 to 700 nm. The photocurable pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the curing by irradiation with radiation is curing by irradiation with ultraviolet rays having an integrated light amount of 3000 mJ / cm ² . The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the cured elastic modulus (G'a10) at 10 ° C. after curing is 90 kPa or more. The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer contains a base polymer, a cross-linking agent, and a photopolymerization initiator. The photocurable pressure-sensitive adhesive sheet according to claim 5, wherein the base polymer contains an acrylic polymer. The photocurable pressure-sensitive adhesive sheet according to claim 5 or 6, wherein the cross-linking agent contains a polyfunctional (meth) acrylate. The pressure-sensitive adhesive layer is a single layer having two opposing main surfaces made of the base polymer.
Concentration of the cross-linking agent and / or the photopolymerization initiator in the region to which the first main surface of one of the two main surfaces belongs when the pressure-sensitive adhesive layer of the single layer is divided into two equal parts in the thickness direction. The photocurable pressure-sensitive adhesive sheet according to any one of claims 5 to 7, wherein the cross-linking agent and / or the photopolymerization initiator has different concentrations in the region to which the other second main surface belongs. The photocurable pressure-sensitive adhesive sheet according to claim 8, wherein the single-layer pressure-sensitive adhesive layer has a concentration gradient of the cross-linking agent and / or the photopolymerization initiator in the thickness direction. Forming a single adhesive layer formed by the base polymer,
The pressure-sensitive adhesive layer is cured and
Prepare a solution of the cross-linking agent and / or the photopolymerization initiator.
The solution is applied to one surface of the cured pressure-sensitive adhesive layer, and the cross-linking agent and / or the photopolymerization initiator contained in the solution permeates from the one surface of the pressure-sensitive adhesive layer in the thickness direction. Let me
The method for producing a photocurable pressure-sensitive adhesive sheet according to claim 8 or 9, which comprises a step of drying the pressure-sensitive adhesive layer. The photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer contains a polymer having a benzophenone structure in a side chain. The photocurable pressure-sensitive adhesive sheet according to claim 11, wherein the pressure-sensitive adhesive layer is a cured product of a pressure-sensitive adhesive composition containing an ethylenically unsaturated compound and a polymer having a benzophenone structure in a side chain. A display panel with multiple light emitting elements arranged on one side of the board,
A self-luminous display device comprising the photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 9, 11 and 12.
The light emitting element of the display panel is sealed with the pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive sheet.
A self-luminous display device in which the adhesive layer is cured. The self-luminous display device according to claim 13, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate. The adhesive layer of the photocurable pressure-sensitive adhesive sheet according to any one of claims 1 to 9, 11 and 12 is laminated on a display panel in which a plurality of light emitting elements are arranged on one side of a substrate, and the light emitting element is described. The method for manufacturing a self-luminous display device according to claim 13, which comprises a step of sealing the pressure-sensitive adhesive layer with a pressure-sensitive adhesive layer and a step of irradiating the pressure-sensitive adhesive layer to cure the pressure-sensitive adhesive layer. The production method according to claim 15, wherein the radiation is ultraviolet rays.

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