Reinforcing film

Abstract

To provide a reinforcing film which includes a base material layer and an adhesive layer, achieves both excellent low elasticity and excellent heat resistance, and hardly causes, for example, IC connection failure.SOLUTION: A reinforcing film according to an embodiment of the present invention is a reinforcing film including a base material layer and a pressure-sensitive adhesive layer, in which the pressure-sensitive adhesive layer is formed of an acrylic pressure-sensitive adhesive, the pressure-sensitive adhesive layer has surface elasticity at 25 °C of from 50kPa to 1000kPa, and an MD direction heat shrinkage rate when the reinforcing film is heated at 180 °C for 5 minutes is 1.0% or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reinforced film. [Background technology]

[0002] Adhesive films are used to reinforce components of various shapes. For example, adhesive films have been reported as reinforcing films that are used not only during device assembly, processing, transportation, etc., but also while the device is in use, while remaining attached to the device surface (e.g., Patent Document 1). In addition to protecting the surface, such adhesive films have the function of reinforcing the device by dispersing impacts on the device and imparting rigidity to flexible devices.

[0003] For example, when joining an integrated circuit (IC) or a flexible printed circuit (FPC) to a semiconductor element substrate (e.g., a TFT substrate), thermocompression bonding is usually performed using an anisotropic conductive film (ACF). Before performing such thermocompression bonding, an adhesive film may be attached to the back side of the semiconductor element substrate to reinforce it (e.g., Patent Document 2).

[0004] In addition, a manufacturing method for so-called flexible devices such as foldable devices and rollable devices, which have been developed in recent years, generally involves forming a release layer and a flexible film substrate on a support substrate such as glass, forming a TFT substrate on the film substrate, and then forming an organic EL layer on top of that. The support substrate is then peeled off to manufacture the flexible device, but because the flexible display layer is very thin, problems with the device can occur due to handling, etc. For this reason, an adhesive film is sometimes attached to the back side to reinforce it (for example, Patent Document 3).

[0005] Substrates of semiconductor elements and flexible devices may be repeatedly bent, and if the bending properties of the adhesive film attached to the substrate, etc. are poor, recovery after bending may be poor, or in the worst case, the film may break due to repeated bending. Specifically, when an adhesive film is attached to a bending portion (for example, a movable bending portion of a folding member), if the adhesive film is bent at an angle, compressive stress acts on the inner diameter side of the bent portion and tensile stress acts on the outer diameter side of the bent portion, causing stress distortion at the bent portion and its surrounding area, which can result in damage to the substrate of the semiconductor element or the flexible device.

[0006] One possible means for solving the above problems is to soften the adhesive contained in the adhesive film to alleviate the stress distortion.

[0007] The storage modulus G' is known as an index of the softness of an adhesive, and there have been proposed techniques for designing adhesives so that the rate of change in modulus (G'(-20) / G'(40)) × 100, based on the storage modulus G'(-20) at -20°C and the storage modulus G'(40) at 40°C, falls within a specified range (Patent Document 4), as well as a technique for designing adhesives so that the rate of change in storage modulus, which is the value obtained by dividing the storage modulus G'(-20) at -20°C by the storage modulus G'(85) at 85°C, falls within a specified range (Patent Document 5).

[0008] The examples of Patent Document 4 report a pressure-sensitive adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a composition of BA / 2EHA / AA / 2HPA=47.8 / 47.8 / 4 / 0.4 (by weight) and 0.9 parts by weight of a crosslinker (B) (Example 1), a pressure-sensitive adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a composition of BA / 4HBA=99 / 1 (by weight) and 0.15 parts by weight of a crosslinker (B) (Example 2), and a pressure-sensitive adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a composition of BA / 2EHA / HEA=47 / 48 / 5 (by weight) and 0.9 parts by weight of a crosslinker (B) (Example 3).

[0009] The examples of Patent Document 5 report pressure-sensitive adhesives obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a BA / 2EHA / 4HBA=54 / 45 / 1 (by weight) composition and 0.15 to 0.35 parts by weight of a crosslinker (B) (Examples 1 to 10), a pressure-sensitive adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a BA / 2EHA / 4HBA=52 / 45 / 3 (by weight) composition and 0.25 parts by weight of a crosslinker (B) (Example 11), and a pressure-sensitive adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) having a BA / 2EHA / 4HBA=50 / 45 / 5 (by weight) composition and 0.25 parts by weight of a crosslinker (B) (Example 12).

[0010] However, when the adhesive is softened and made low elastic, the creep value generally increases. As a result, adhesive tapes using conventional low elastic adhesives have an increased fluidity of the adhesive when heated, which can cause the adhesive to distort significantly when, for example, bumps are pressed onto an integrated circuit (IC), which in turn causes distortion in the semiconductor device substrate and leads to connection failures. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent No. 6366199 [Patent Document 2] Patent No. 5600039 [Patent Document 3] Patent No. 6376271 [Patent Document 4] Patent No. 6697359 [Patent Document 5] Japanese Patent Publication No. 2020-139034 Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention is to provide a reinforced film comprising a base layer and a pressure-sensitive adhesive layer, which has both excellent low elasticity and excellent heat resistance, and is less likely to cause, for example, poor IC connection. [Means for solving the problem]

[0013] The reinforcement film according to an embodiment of the present invention comprises: A reinforced film comprising a base layer and a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is made of an acrylic pressure-sensitive adhesive, the pressure-sensitive adhesive layer has a surface elastic modulus of 50 kPa to 1000 kPa at 25°C; The reinforced film has a heat shrinkage rate in the MD direction of 1.0% or less when heated at 180°C for 5 minutes.

[0014] In one embodiment, the reinforcing film according to the embodiment of the present invention has an adhesive strength to a polyimide film at 25° C. of 5.0 N / 25 mm or more.

[0015] In one embodiment, the reinforced film according to the embodiment of the present invention has a transmittance of 80% or more at a wavelength of 550 nm.

[0016] In one embodiment, the acrylic pressure-sensitive adhesive is a photocurable acrylic pressure-sensitive adhesive.

[0017] In one embodiment, the pressure-sensitive adhesive layer has a storage modulus G' at -20°C of 80 kPa to 300 kPa.

[0018] An optical member according to an embodiment of the present invention includes a reinforcing film according to an embodiment of the present invention.

[0019] An electronic component according to an embodiment of the present invention includes a reinforcing film according to an embodiment of the present invention. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a reinforced film that includes a base layer and a pressure-sensitive adhesive layer, which has both excellent low elasticity and excellent heat resistance, and is less likely to cause poor IC connections, for example. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic cross-sectional view of one embodiment of the reinforced film of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic", the expression "(meth)acrylate" means "acrylate and / or methacrylate", the expression "(meth)allyl" means "allyl and / or methallyl", and the expression "(meth)acrolein" means "acrolein and / or methacrolein". Furthermore, in this specification, the expression "acid (salt)" means "acid and / or its salt". Examples of salts include alkali metal salts and alkaline earth metal salts, and specific examples include sodium salts and potassium salts.

[0023] ≪≪1. Reinforcing film≫≫ The reinforcing film according to an embodiment of the present invention includes a substrate layer and a pressure-sensitive adhesive layer.

[0024] The substrate layer may be one layer or two or more layers, but is preferably one layer in that the effects of the present invention can be more effectively exhibited.

[0025] The pressure-sensitive adhesive layer may be one layer or two or more layers, but is preferably one layer in that the effects of the present invention can be more effectively exhibited.

[0026] The reinforcing film according to an embodiment of the present invention may include any other appropriate layer depending on the purpose, as long as it includes a base material layer and a pressure-sensitive adhesive layer, as long as the effects of the present invention are not impaired.

[0027] The reinforcing film according to an embodiment of the present invention has a structure in which a substrate layer and a pressure-sensitive adhesive layer are directly laminated together, in order to further exhibit the effects of the present invention.

[0028] In one embodiment of the reinforced film of the present invention, as shown in FIG. 1, a reinforced film 100 is composed of a base layer 10 and a pressure-sensitive adhesive layer 20.

[0029] The reinforcing film according to the embodiment of the present invention may be provided with any appropriate release liner on the surface of the pressure-sensitive adhesive layer opposite the base layer for protection until use, etc.

[0030] Examples of release liners include release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is silicone-treated, and release liners in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin. Examples of plastic films as liner substrates include polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

[0031] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, even more preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0032] The thickness of the reinforced film according to the embodiment of the present invention is preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, even more preferably 10 μm to 150 μm, particularly preferably 20 μm to 100 μm, and most preferably 30 μm to 80 μm. When the thickness of the reinforced film according to the embodiment of the present invention is within the above range, the effects of the present invention can be more effectively exhibited.

[0033] The reinforced film according to an embodiment of the present invention has a MD heat shrinkage of 1.0% or less, preferably 0.8% or less, more preferably 0.6% or less, even more preferably 0.5% or less, and particularly preferably 0.4% or less, when heated at 180°C for 5 minutes. The MD heat shrinkage is an index that can appropriately evaluate the heat resistance of the reinforced film, and by adjusting this MD heat shrinkage to a very small value as described above, the reinforced film according to an embodiment of the present invention can exhibit excellent heat resistance. If the MD heat shrinkage is larger than the above range, it may be difficult to exhibit excellent heat resistance. A method for measuring the MD heat shrinkage will be described in detail later.

[0034] In the reinforced film according to an embodiment of the present invention, the pressure-sensitive adhesive layer has a surface elasticity modulus at 25°C of 50 kPa to 1000 kPa, preferably 100 kPa to 900 kPa, more preferably 120 kPa to 800 kPa, even more preferably 140 kPa to 700 kPa, even more preferably 160 kPa to 600 kPa, particularly preferably 180 kPa to 500 kPa, and most preferably 200 kPa to 400 kPa. The surface elasticity modulus is an index that can appropriately evaluate the degree of low elasticity of the pressure-sensitive adhesive layer, and by adjusting this surface elasticity modulus within the above specific range, the reinforced film according to an embodiment of the present invention can exhibit excellent low elasticity. If the surface elasticity modulus is outside the above specific range, it may be difficult to exhibit excellent low elasticity. A method for measuring the surface elasticity modulus will be described in detail below.

[0035] The reinforcing film according to an embodiment of the present invention preferably has an adhesive strength to a polyimide film at 25°C of 5.0 N / 25 mm or more, more preferably 5.0 N / 25 mm to 30 N / 25 mm, even more preferably 5.0 N / 25 mm to 20 N / 25 mm, and particularly preferably 5.0 N / 25 mm to 10 N / 25 mm. The adhesive strength to the polyimide film at 25°C is an index that can appropriately evaluate the adhesive strength of the reinforcing film to a semiconductor element substrate, a flexible device, or the like. By adjusting this adhesive strength within the above-mentioned specific range, the reinforcing film according to an embodiment of the present invention can be appropriately attached to a semiconductor element substrate, a flexible device, or the like. If the adhesive strength is outside the above-mentioned specific range, it may be difficult to appropriately adhere the film to a semiconductor element substrate, a flexible device, or the like as a reinforcing film. The method for measuring the adhesive strength to the polyimide film at 25°C will be described in detail below.

[0036] The reinforcing film according to an embodiment of the present invention preferably has an adhesive strength to a polyimide film at −20°C of 10 N / 25 mm or more, more preferably 10 N / 25 mm to 40 N / 25 mm, even more preferably 12 N / 25 mm to 35 N / 25 mm, and particularly preferably 13 N / 25 mm to 30 N / 25 mm. The adhesive strength to the polyimide film at −20°C is an index that can appropriately evaluate the adhesive strength (particularly adhesive strength at relatively low temperatures) of the reinforcing film to a semiconductor element substrate or a flexible device. By adjusting this adhesive strength within the above-mentioned specific range, the reinforcing film according to an embodiment of the present invention can be appropriately attached to a semiconductor element substrate or a flexible device even at relatively low temperatures. If the adhesive strength is outside the above-mentioned specific range, it may be difficult to appropriately adhere the film as a reinforcing film to a semiconductor element substrate or a flexible device at relatively low temperatures. The method for measuring the adhesive strength to the polyimide film at −20°C will be described in detail below.

[0037] The reinforcing film according to an embodiment of the present invention preferably has an adhesive strength to a polyimide film at 180°C of 0.1 N / 25 mm or more, more preferably 0.1 N / 25 mm to 5 N / 25 mm, even more preferably 0.1 N / 25 mm to 1.0 N / 25 mm, and particularly preferably 0.1 N / 25 mm to 0.6 N / 25 mm. The adhesive strength to a polyimide film at 180°C is an index that can appropriately evaluate the adhesive strength (particularly adhesive strength in relatively high temperature ranges) of the reinforcing film to semiconductor element substrates, flexible devices, etc. By adjusting this adhesive strength within the above-mentioned specific range, the reinforcing film according to an embodiment of the present invention can be appropriately attached to semiconductor element substrates, flexible devices, etc., even in relatively high temperature ranges. If the adhesive strength is outside the above-mentioned specific range, it may be difficult to appropriately adhere the film as a reinforcing film to semiconductor element substrates, flexible devices, etc., in relatively high temperature ranges. The method for measuring the adhesive strength to the polyimide film at 180°C will be described in detail below.

[0038] The reinforced film according to an embodiment of the present invention preferably has a transmittance at a wavelength of 550 nm of 80% or more, preferably 84% or more, more preferably 86% or more, even more preferably 88% or more, and particularly preferably 90% or more. The transmittance is an index for appropriately evaluating the inspectability of the reinforced film, and by adjusting the transmittance to a very large value as described above, the reinforced film according to an embodiment of the present invention can exhibit excellent inspectability. If the transmittance is small and outside the above range, it may be difficult to exhibit excellent inspectability. The method for measuring the transmittance will be described in detail below.

[0039] In the reinforced film according to an embodiment of the present invention, the pressure-sensitive adhesive layer preferably has a storage modulus G' at -20°C of 80 kPa to 300 kPa, more preferably 100 kPa to 250 kPa, even more preferably 130 kPa to 220 kPa, and particularly preferably 150 kPa to 200 kPa. The storage modulus G' at -20°C is an index that can appropriately evaluate the stress relaxation property of the pressure-sensitive adhesive layer (particularly, stress relaxation property in a relatively low temperature range). By adjusting the storage modulus G' at -20°C to fall within the above-mentioned specific range, the reinforced film according to an embodiment of the present invention can exhibit excellent stress relaxation property even in a relatively low temperature range, and can therefore exhibit very excellent low elasticity. If the storage modulus G' at -20°C falls outside the above-mentioned specific range, it may be difficult to exhibit excellent stress relaxation property. A method for measuring the storage modulus G' at -20°C will be described in detail below.

[0040] In the reinforced film according to an embodiment of the present invention, the pressure-sensitive adhesive layer preferably has a storage modulus G' at 25°C of 20 kPa to 200 kPa, more preferably 25 kPa to 150 kPa, even more preferably 27 kPa to 100 kPa, and particularly preferably 30 kPa to 60 kPa. The storage modulus G' at 25°C is an index that can appropriately evaluate the stress relaxation property of the pressure-sensitive adhesive layer (particularly, stress relaxation property in the room temperature range). By adjusting the storage modulus G' at 25°C to fall within the above-mentioned specific range, the reinforced film according to an embodiment of the present invention can exhibit excellent stress relaxation property in the room temperature range, and ultimately can exhibit excellent low elasticity. If the storage modulus G' at 25°C falls outside the above-mentioned specific range, it may be difficult to exhibit excellent stress relaxation property. A method for measuring the storage modulus G' at 25°C will be described in detail below.

[0041] In the reinforced film according to an embodiment of the present invention, the pressure-sensitive adhesive layer preferably has a storage modulus G' at 180°C of 1 to 100 kPa, more preferably 5 to 50 kPa, even more preferably 8 to 30 kPa, and particularly preferably 10 to 20 kPa. The storage modulus G' at 180°C is an index that can appropriately evaluate the stress relaxation property of the pressure-sensitive adhesive layer (particularly, stress relaxation property in a high-temperature range). By adjusting the storage modulus G' at 180°C to fall within the above-mentioned specific range, the reinforced film according to an embodiment of the present invention can exhibit excellent stress relaxation property in a high-temperature range, and can therefore exhibit excellent low elasticity. If the storage modulus G' at 180°C falls outside the above-mentioned specific range, it may be difficult to exhibit excellent stress relaxation property. A method for measuring the storage modulus G' at 180°C will be described in detail below.

[0042] ≪1-1. Base material layer≫ The thickness of the substrate layer is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, even more preferably 10 μm to 100 μm, particularly preferably 15 μm to 80 μm, and most preferably 20 μm to 60 μm. When the thickness of the substrate layer is within the above range, the effects of the present invention can be more effectively exhibited.

[0043] Any appropriate material can be used as the material for the substrate layer as long as it does not impair the effects of the present invention. A typical example of the material for such a substrate layer is a resin material.

[0044] Examples of resin materials for the substrate layer include acrylic resins such as polyimide (PI), polyether ether ketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorine-based resins, and cyclic olefin polymers. The substrate layer may be made of one or more resin materials.

[0045] The base layer preferably has a tensile modulus of elasticity measured in a peel test at 200 mm / min at 25°C of 1.0 GPa to 10 GPa, more preferably 2.0 GPa to 9.0 GPa, even more preferably 3.0 GPa to 8.0 GPa, and particularly preferably 4.0 GPa to 7.0 GPa. The tensile modulus measured in a peel test at 200 mm / min at 25°C is an index that can appropriately evaluate the compatibility of heat resistance and flexibility of the base layer. By adjusting the tensile modulus measured in a peel test at 200 mm / min at 25°C to fall within the above-mentioned specific range, the reinforced film according to the embodiment of the present invention can more effectively achieve both excellent low elasticity and excellent heat resistance. If the tensile modulus measured in a peel test at 200 mm / min at 25°C is outside the above-mentioned specific range, the reinforced film according to the embodiment of the present invention may find it difficult to achieve both excellent low elasticity and excellent heat resistance. The method for measuring the tensile modulus by the peel test at 200 mm / min at 25° C. will be described in detail later.

[0046] Examples of resin materials for the substrate layer that can adjust the tensile modulus of elasticity in a peel test at 200 mm / min at 25°C to fall within the preferred range include polyimide (PI) and annealed polyethylene terephthalate (annealed PET).

[0047] <1-2. Adhesive layer> The pressure-sensitive adhesive layer is made of an acrylic pressure-sensitive adhesive, which is formed from an acrylic pressure-sensitive adhesive composition.

[0048] The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, even more preferably 3 μm to 100 μm, particularly preferably 5 μm to 50 μm, and most preferably 10 μm to 35 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the effects of the present invention can be more effectively exhibited.

[0049] An acrylic pressure-sensitive adhesive can be defined as something formed from an acrylic pressure-sensitive adhesive composition in this way. This is because an acrylic pressure-sensitive adhesive becomes an acrylic pressure-sensitive adhesive when an acrylic pressure-sensitive adhesive composition undergoes a crosslinking reaction due to heating, ultraviolet irradiation, etc., and therefore it is impossible and almost impractical to directly identify an acrylic pressure-sensitive adhesive by its structure ("impossible / impractical circumstances"). Therefore, the definition of "something formed from an acrylic pressure-sensitive adhesive composition" appropriately identifies an acrylic pressure-sensitive adhesive as a "product."

[0050] Any appropriate method can be adopted as a method for forming the acrylic pressure-sensitive adhesive as long as the effects of the present invention are not impaired. Examples of methods for forming such an acrylic pressure-sensitive adhesive include a method in which an acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, heated or dried as necessary, and cured as necessary to form the acrylic pressure-sensitive adhesive into a sheet on the substrate.

[0051] Any appropriate means can be used to apply the acrylic pressure-sensitive adhesive composition as long as the effects of the present invention are not impaired. Examples of such application means include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0052] The acrylic pressure-sensitive adhesive composition can be heated or dried by any appropriate means as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to 60°C to 180°C, or performing an aging treatment at a temperature around room temperature.

[0053] The acrylic pressure-sensitive adhesive composition can be cured by any appropriate means as long as the effects of the present invention are not impaired, including, for example, ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0054] Representative methods for forming an acrylic pressure-sensitive adhesive from an acrylic pressure-sensitive adhesive composition include a method for forming a photocurable acrylic pressure-sensitive adhesive by the photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator, and a method for forming a thermosetting acrylic pressure-sensitive adhesive by the crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer prepared by solution polymerization using a thermal polymerization initiator. That is, representative acrylic pressure-sensitive adhesives include photocurable acrylic pressure-sensitive adhesives formed by the photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) (P1) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator, and thermosetting acrylic pressure-sensitive adhesives formed by the crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P2) prepared by solution polymerization using a thermal polymerization initiator.

[0055] <1-2-1. Acrylic polymer (P1)> One embodiment of the acrylic polymer is an acrylic polymer (P1) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator. As a method for polymerization using a photopolymerization initiator, any appropriate method, such as a conventionally known method, can be adopted as long as it does not impair the effects of the present invention. Polymerization using a photopolymerization initiator is typically carried out by irradiating light such as UV.

[0056] The acrylic polymer (P1) is preferably an acrylic partial polymer (sometimes referred to as an acrylic prepolymer). The acrylic partial polymer is different from one obtained as a complete polymer of the monomer components (preferably a polymer with a polymerization conversion rate of more than 95% by weight), and is a partial polymer obtained by reducing the polymerization conversion rate of the monomer components to preferably 95% by weight or less.

[0057] The polymerization conversion rate of the acrylic partial polymer is preferably 70% by weight or less, more preferably 60% by weight or less, even more preferably 50% by weight or less, particularly preferably 40% by weight or less, and most preferably 35% by weight or less. The lower limit of the polymerization conversion rate of the acrylic partial polymer is preferably 1% by weight or more, more preferably 5% by weight or more.

[0058] The acrylic polymer (P1) is obtained by polymerizing a monomer component (M1). The monomer component (M1) does not include a crosslinking agent, which may be contained in the acrylic pressure-sensitive adhesive composition and will be described later. When obtaining the acrylic polymer (P1) by polymerization, in addition to the monomer component (M1) and the photopolymerization initiator, any appropriate additive may be used as long as it does not impair the effects of the present invention.

[0059] The acrylic polymer (P1) can be defined as something obtained by polymerizing the monomer component (M1) in this way. This is because the acrylic polymer (P1) becomes the acrylic polymer (P1) through the polymerization reaction of the monomer component (M1), and there are circumstances that make it impossible and almost impractical to directly identify the acrylic polymer (P1) by its structure ("impossible / impractical circumstances"). Therefore, the acrylic polymer (P1) is appropriately defined as a "product" by the definition of "something obtained by polymerizing the monomer component (M1)."

[0060] The acrylic polymer (P1) preferably has a Tg of −80° C. to −15° C., more preferably −70° C. to −25° C., even more preferably −65° C. to −30° C., and particularly preferably −60° C. to −35° C., in order to further exhibit the effects of the present invention. By adjusting the Tg of the acrylic polymer (P1) to fall within the above specific range, the reinforced film according to the embodiment of the present invention can more effectively achieve excellent low elasticity.

[0061] The Tg of the acrylic polymer (P1) is a value calculated from the Fox equation based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P1) and the weight fraction (copolymerization ratio by weight) of the monomer. The Fox equation, as shown below, is a relational expression 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)

[0062] In the Fox formula, Tg represents the glass transition temperature (unit: K) of the copolymer, Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), and Tgi represents the glass transition temperature (unit: K) of a homopolymer of monomer i. As the Tg of the homopolymer, a value listed in publicly available documents is adopted.

[0063] As the Tg of the homopolymer, for example, the following specific values ​​can be used: n-Butyl acrylate (BA): -55℃ Lauryl acrylate (LA): -23℃ 2-Ethylhexyl acrylate (2EHA): -70℃ 2-Hydroxyethyl acrylate (2HEA): -15°C 4-Hydroxybutyl acrylate (2HBA): -40℃ N-vinyl-2-pyrrolidone (NVP): 80℃

[0064] For the Tg of homopolymers other than those exemplified above, the values ​​listed in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When multiple values ​​are listed in the "Polymer Handbook," the conventional value is used. For monomers not listed in the "Polymer Handbook," the catalog value from the monomer manufacturer is used. For the Tg of homopolymers of monomers not listed in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP 2007-51271 A is used.

[0065] The monomer component (M1) preferably contains an alkyl (meth)acrylate (a1) and a polar group-containing monomer (b1). The alkyl (meth)acrylate (a1) may be of one type or two or more types. The polar group-containing monomer (b1) may be of one type or two or more types.

[0066] [1-2-1-1. Alkyl (meth)acrylate (a1)] The alkyl group in the ester moiety of the alkyl (meth)acrylate (a1) (hereinafter sometimes referred to as the "alkyl group in the ester moiety") does not include alkyl groups containing a hydroxyl group or alkyl groups containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a1) is clearly distinguished from the polar group-containing monomer (b1).

[0067] The content of alkyl (meth)acrylate (a1) in the monomer component (M1) is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, even more preferably 80% by weight to 99% by weight, particularly preferably 82% by weight to 99% by weight, and most preferably 85% by weight to 99% by weight, in order to further exhibit the effects of the present invention.

[0068] The alkyl group in the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 18 carbon atoms, even more preferably an alkyl group having 2 to 16 carbon atoms, particularly preferably an alkyl group having 3 to 14 carbon atoms, and most preferably an alkyl group having 6 to 14 carbon atoms, in terms of being able to further exert the effects of the present invention.

[0069] The alkyl group of the ester moiety is preferably a chain alkyl group, which can further exert the effects of the present invention. Here, chain alkyl group means both linear and branched.

[0070] Examples of the alkyl(meth)acrylate (a1) in which the alkyl group in the ester moiety is a chain alkyl group having 1 to 20 carbon atoms include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, s-butyl(meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, and isopropyl(meth)acrylate. Examples of such acrylates include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0071] In order to further enhance the effects of the present invention, the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1) preferably has a glass transition temperature (Tg) of its homopolymer (homopolymer) of -10°C or lower, more preferably -12°C or lower, even more preferably -15°C or lower, particularly preferably -18°C or lower, and most preferably -20°C or lower. The lower limit of the glass transition temperature (Tg) is preferably -80°C or higher. The glass transition temperature (Tg) of the homopolymer (homopolymer) of the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1) can affect the adhesive properties and low elasticity of the acrylic polymer (P1). By using an alkyl(meth)acrylate whose homopolymer (homopolymer) has a glass transition temperature (Tg) within the above range as the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1), the adhesive properties and low elasticity of the acrylic polymer (P1) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0072] Here, the glass transition temperature Tg of a homopolymer of alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) can be a value described in a publicly known document, such as the value described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). When multiple values ​​are described in the "Polymer Handbook," the conventional value is used. For alkyl (meth)acrylates not described in the "Polymer Handbook," the value listed in the catalog of the monomer manufacturer is used. For alkyl (meth)acrylate homopolymers not described in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP 2007-51271 A is used.

[0073] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) preferably contains an alkyl (meth)acrylate (a1-1) whose homopolymer has a glass transition temperature Tg in the range of −40° C. to −10° C. (preferably −35° C. to −15° C., more preferably −30° C. to −20° C.) Inclusion of the alkyl (meth)acrylate (M1) in the alkyl (meth)acrylate (a1-1) allows the effects of the present invention to be further enhanced.

[0074] An example of the alkyl(meth)acrylate (a1-1) is lauryl acrylate (LA) (the glass transition temperature Tg of its homopolymer is −23° C.).

[0075] The content of alkyl (meth)acrylate (a1-1) in the total amount of alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 10 to 80% by weight, more preferably 20 to 70% by weight, even more preferably 25 to 60% by weight, particularly preferably 30 to 55% by weight, and most preferably 35 to 50% by weight, in order to further exhibit the effects of the present invention.

[0076] The content of the alkyl (meth)acrylate (a1-1) in the total amount of the monomer component (M1) is preferably 10% by weight to 80% by weight, more preferably 15% by weight to 70% by weight, even more preferably 20% by weight to 60% by weight, particularly preferably 25% by weight to 50% by weight, and most preferably 30% by weight to 45% by weight, in order to further exhibit the effects of the present invention.

[0077] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) preferably contains an alkyl (meth)acrylate (a1-2) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.). When the alkyl (meth)acrylate (M1) contains the alkyl (meth)acrylate (a1-2), the effects of the present invention can be further enhanced.

[0078] An example of the alkyl(meth)acrylate (a1-2) is 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer is −70° C.).

[0079] The content of alkyl (meth)acrylate (a1-2) in the total amount of alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 20% by weight to 90% by weight, more preferably 30% by weight to 80% by weight, even more preferably 40% by weight to 75% by weight, particularly preferably 45% by weight to 70% by weight, and most preferably 50% by weight to 65% by weight, in order to further exhibit the effects of the present invention.

[0080] The content of the alkyl (meth)acrylate (a1-2) in the total amount of the monomer component (M1) is preferably 10% by weight to 80% by weight, more preferably 20% by weight to 75% by weight, even more preferably 30% by weight to 70% by weight, particularly preferably 35% by weight to 65% by weight, and most preferably 40% by weight to 60% by weight, in order to further exhibit the effects of the present invention.

[0081] The monomer component (M1) may contain, as the alkyl(meth)acrylate, an alkyl(meth)acrylate (a1-3) whose homopolymer has a glass transition temperature Tg in the range of more than -60°C and less than -40°C, within the range that does not impair the effects of the present invention.

[0082] An example of the alkyl(meth)acrylate (a1-3) is n-butyl acrylate (BA) (the glass transition temperature Tg of its homopolymer is −55° C.).

[0083] The content of alkyl (meth)acrylate (a1-3) in the total amount of alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 40% by weight or less, more preferably 30% by weight or less, even more preferably 20% by weight or less, particularly preferably 10% by weight or less, and most preferably 5% by weight or less, in order to further exhibit the effects of the present invention.

[0084] The content of alkyl (meth)acrylate (a1-3) in the total amount of monomer component (M1) is preferably 40% by weight or less, more preferably 30% by weight or less, even more preferably 20% by weight or less, particularly preferably 10% by weight or less, and most preferably 5% by weight or less, in order to further exhibit the effects of the present invention.

[0085] [1-2-1-2. Polar group-containing monomer (b1)] The content of the polar group-containing monomer (b1) in the monomer component (M1) is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, even more preferably 1 to 20% by weight, particularly preferably 1 to 18% by weight, and most preferably 1 to 15% by weight, in order to further exhibit the effects of the present invention.

[0086] In order to further exert the effects of the present invention, the polar group-containing monomer (b1) preferably contains at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, and more preferably contains both a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0087] The hydroxyl group-containing monomer (b1-1) may be of one type only, or of two or more types.

[0088] Examples of the hydroxyl group-containing monomer (b1-1) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate; and N-hydroxyethyl (meth)acrylamide.

[0089] In order to further enhance the effects of the present invention, the hydroxyl-containing monomer (b1-1) preferably has a glass transition temperature Tg of its homopolymer of -60°C to -10°C, more preferably -55°C to -10°C, and even more preferably -45°C to -10°C. The glass transition temperature Tg of the homopolymer of the hydroxyl-containing monomer (b1-1) can affect the adhesive properties and low elasticity of the acrylic polymer (P1). By using a hydroxyl-containing monomer whose homopolymer has a glass transition temperature Tg within the above range as the hydroxyl-containing monomer (b1-1) that can be contained in the monomer component (M1), the adhesive properties and low elasticity of the acrylic polymer (P1) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0090] With regard to the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1-1), the explanation of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0091] In terms of further exerting the effects of the present invention, the hydroxyl group-containing monomer (b1-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C).

[0092] The content of the hydroxyl group-containing monomer (b1-1) in the polar group-containing monomer (b1) is preferably 20% by weight to 100% by weight, more preferably 25% by weight to 95% by weight, even more preferably 30% by weight to 90% by weight, particularly preferably 35% by weight to 85% by weight, and most preferably 40% by weight to 80% by weight, in order to further exhibit the effects of the present invention.

[0093] The content of the hydroxyl group-containing monomer (b1-1) in the monomer component (M1) is preferably 0.05% by weight to 30% by weight, more preferably 0.1% by weight to 20% by weight, even more preferably 1% by weight to 15% by weight, particularly preferably 2% by weight to 10% by weight, and most preferably 4% by weight to 9% by weight, in order to further exhibit the effects of the present invention.

[0094] The monomer (b1-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0095] Examples of the monomer (b1-2) having a polar group other than a hydroxyl group include N-vinyl-2-pyrrolidone, nitrogen-containing monomers other than N-vinyl-2-pyrrolidone, carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, acid anhydride group-containing monomers, vinyl esters (e.g., vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, amide group-containing monomers, epoxy group-containing monomers, (meth)acryloylmorpholine, and vinyl ethers.

[0096] Examples of carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0097] Examples of nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include nitrogen-containing vinyl monomers such as methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, and N-vinylcaprolactam; and cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile.

[0098] In order to further enhance the effects of the present invention, the glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group is preferably −30°C to 100°C, more preferably −20°C to 95°C, and even more preferably −10°C to 90°C. The glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group can affect the adhesive properties and low elasticity of the acrylic polymer (P1). By using a monomer having a polar group other than a hydroxyl group (b1-2) whose homopolymer has a glass transition temperature Tg within the above range as the monomer having a polar group other than a hydroxyl group that can be contained in the monomer component (M1), the adhesive properties and low elasticity of the acrylic polymer (P1) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0099] As the monomer (b1-2) having a polar group other than a hydroxyl group, a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg of 50° C. to 100° C. is preferred, as it can further exhibit the effects of the present invention. The glass transition temperature Tg of the homopolymer of this monomer is preferably 60° C. to 95° C., and more preferably 70° C. to 90° C.

[0100] With regard to the glass transition temperature Tg of a homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group, the explanation of the glass transition temperature Tg of a homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0101] In terms of further exerting the effects of the present invention, the monomer (b1-2) having a polar group other than a hydroxyl group is preferably N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80°C).

[0102] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the polar group-containing monomer (b1) is preferably 1 to 80% by weight, more preferably 5 to 75% by weight, even more preferably 10 to 70% by weight, particularly preferably 15 to 65% by weight, and most preferably 20 to 60% by weight, in order to further exhibit the effects of the present invention.

[0103] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the monomer component (M1) is preferably 0.01 to 20% by weight, more preferably 0.05 to 15% by weight, even more preferably 0.1 to 12% by weight, particularly preferably 0.3 to 10% by weight, and most preferably 0.5 to 9% by weight, in order to further exhibit the effects of the present invention.

[0104] In order to further exert the effects of the present invention, the monomer component (M1) preferably contains an alkyl(meth)acrylate (a1) and at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, more preferably contains an alkyl(meth)acrylate (a1), a hydroxyl group-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group, and even more preferably contains a galvanic acid of a homopolymer thereof. The alkyl(meth)acrylate (a1-1) has a glass transition temperature Tg in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), the alkyl(meth)acrylate (a1-2) has a glass transition temperature Tg of its homopolymer in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), a hydroxyl group-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0105] In order to further exert the effects of the present invention, the total content of the alkyl (meth)acrylate (a1-1) whose homopolymer has a glass transition temperature Tg in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), the alkyl (meth)acrylate (a1-2) whose homopolymer has a glass transition temperature Tg in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), the hydroxyl group-containing monomer (b1-1), and the monomer having a polar group other than a hydroxyl group (b1-2) in the monomer component (M1) is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0106] In terms of being able to further exert the effects of the present invention, the monomer component (M1) specifically preferably contains lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, and N-vinyl-2-pyrrolidone.

[0107] [1-2-1-3. Other Monomers (c1)] The monomer component (M1) may contain another monomer (c1) that does not fall into either the alkyl (meth)acrylate (a1) or the polar group-containing monomer (b1). The other monomer (c1) can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (P1), adjusting the adhesive properties, etc. The other monomer may be one type or two or more types.

[0108] The content of the other monomer (c1) in the monomer component (M1) is preferably 20% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0109] [1-2-1-4. Photopolymerization initiator] The photopolymerization initiator can be appropriately selected from any appropriate photopolymerization initiator depending on the type of polymerization method, and the photopolymerization initiator may be one type or two or more types.

[0110] Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

[0111] Specific examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one (a commercially available product is, for example, the trade name "OMNIRAD651" manufactured by IGM Resins BV), and anisole methyl ether.

[0112] Specific examples of acetophenone-based photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone (a commercially available product is, for example, the trade name "OMNIRAD184" manufactured by IGM Resins BV), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (a commercially available product is, for example, the trade name "OMNIRAD2959" manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone.

[0113] Specific examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropan-1-one, and the like.

[0114] Specific examples of aromatic sulfonyl chloride photopolymerization initiators include 2-naphthalenesulfonyl chloride.

[0115] Specific examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0116] Specific examples of benzoin-based photopolymerization initiators include benzoin.

[0117] Specific examples of benzyl-based photopolymerization initiators include benzyl.

[0118] Specific examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone.

[0119] Specific examples of the ketal-based photopolymerization initiator include benzyl dimethyl ketal.

[0120] Specific examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0121] Specific examples of the acylphosphine photopolymerization initiator include bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)(2,4,4-trimethylpentyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-n-butylphosphine oxide, bis(2,6-dimethoxybenzoyl)-(2-methylpropan-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropan-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropan-1-yl)phosphine oxide, and bis(2,6-dimethoxybenzoyl)phenylphosphine oxide. Bis(2,6-dimethoxybenzoyl)cyclohexylphosphine oxide, Bis(2,6-dimethoxybenzoyl)octylphosphine oxide, Bis(2-methoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, Bis(2-methoxybenzoyl)(1-methylpropan-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(1-methylpropan-1-yl)phosphine oxide Bis(2,6-dibutoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, bis(2,4-dimethoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)(2,4-dipentoxyphenyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)benzylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylpropylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2 -phenylethylphosphine oxide, bis(2,6-dimethoxybenzoyl)benzylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylpropylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylethylphosphine oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diisopropylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-4-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,3,5,6-tetramethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)isobutylphosphine oxide, 2,6-dimethythoxybenzoyl-2,4,6-trimethylbenzoyl-n-butylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dibutoxyphenylphosphine oxide, 1,10-bis[bis(2,4,6-trimethylbenzoyl)phosphine oxide]decane, tri(2-methylbenzoyl)phosphine oxide, etc.

[0122] The amount of the photopolymerization initiator used can be set to any appropriate amount as long as it does not impair the effects of the present invention. The amount of the photopolymerization initiator used is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, even more preferably 0.007 to 3 parts by weight, and particularly preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the monomer component (M1), in order to further exhibit the effects of the present invention.

[0123] <1-2-2. Acrylic polymer (P2)> One embodiment of the acrylic polymer is an acrylic polymer (P2) prepared by solution polymerization using a thermal polymerization initiator. As a polymerization method using a thermal polymerization initiator, any appropriate method, such as a conventionally known method, can be adopted as long as it does not impair the effects of the present invention.

[0124] The acrylic polymer (P2) is obtained by polymerizing a monomer component (M2). The monomer component (M2) does not include a crosslinking agent, which may be contained in the acrylic pressure-sensitive adhesive composition and will be described later. When obtaining the acrylic polymer (P2) by polymerization, in addition to the monomer component (M2) and the thermal polymerization initiator, any appropriate additive may be used as long as it does not impair the effects of the present invention.

[0125] The acrylic polymer (P2) can be defined as something obtained by polymerizing the monomer component (M2) in this way. This is because the acrylic polymer (P2) becomes the acrylic polymer (P2) through the polymerization reaction of the monomer component (M2), and there are circumstances that make it impossible and almost impractical to directly identify the acrylic polymer (P2) by its structure ("impossible / impractical circumstances"). Therefore, the acrylic polymer (P2) is appropriately defined as a "product" by the definition of "something obtained by polymerizing the monomer component (M2)."

[0126] The acrylic polymer (P2) preferably has a Tg of −85° C. to −30° C., more preferably −80° C. to −40° C., even more preferably −75° C. to −50° C., and particularly preferably −70° C. to −60° C., in order to further exhibit the effects of the present invention. By adjusting the Tg of the acrylic polymer (P2) to fall within the above specific range, the reinforced film according to the embodiment of the present invention can more effectively achieve excellent low elasticity.

[0127] The Tg of the acrylic polymer (P2) refers to the value calculated from the Fox formula based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P2) and the weight fraction (copolymerization ratio by weight) of the monomer. The Fox formula and the Tg of various homopolymers can be found in the explanation in <1-2-1. Acrylic polymer (P1)>.

[0128] The monomer component (M2) preferably contains an alkyl (meth)acrylate (a2) and a polar group-containing monomer (b2). The alkyl (meth)acrylate (a2) may be of one type or two or more types. The polar group-containing monomer (b2) may be of one type or two or more types.

[0129] [1-2-2-1. Alkyl (meth)acrylate (a2)] The alkyl group in the ester moiety of the alkyl (meth)acrylate (a2) (hereinafter sometimes referred to as the "alkyl group in the ester moiety") does not include an alkyl group containing a hydroxyl group or an alkyl group containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a2) is clearly distinguished from the polar group-containing monomer (b2).

[0130] The content of alkyl (meth)acrylate (a2) in the monomer component (M2) is preferably 70% by weight to 99.9% by weight, more preferably 80% by weight to 99.5% by weight, even more preferably 90% by weight to 99.2% by weight, still more preferably 93% by weight to 99.2% by weight, particularly preferably 95% by weight to 99% by weight, and most preferably 97% by weight to 99% by weight, in order to further exhibit the effects of the present invention.

[0131] The alkyl group in the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 18 carbon atoms, even more preferably an alkyl group having 2 to 16 carbon atoms, particularly preferably an alkyl group having 3 to 14 carbon atoms, and most preferably an alkyl group having 4 to 14 carbon atoms, in terms of being able to further exert the effects of the present invention.

[0132] The alkyl group of the ester moiety is preferably a chain alkyl group, which can further exert the effects of the present invention. Here, chain alkyl group means both linear and branched.

[0133] For alkyl(meth)acrylate (a2) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms, the explanation for alkyl(meth)acrylate (a1) in which the alkyl group of the ester moiety is a chain alkyl group having 1 to 20 carbon atoms in the section [1-2-1-1. Alkyl(meth)acrylate (a1)] can be cited.

[0134] In order to further enhance the effects of the present invention, the alkyl(meth)acrylate (a2) that can be contained in the monomer component (M2) preferably has a glass transition temperature (Tg) of its homopolymer (homopolymer) of -10°C or lower, more preferably -12°C or lower, even more preferably -15°C or lower, particularly preferably -18°C or lower, and most preferably -20°C or lower. The lower limit of the glass transition temperature (Tg) is preferably -80°C or higher. The glass transition temperature (Tg) of the homopolymer (homopolymer) of the alkyl(meth)acrylate (a2) that can be contained in the monomer component (M2) can affect the adhesive properties and low elasticity of the acrylic polymer (P2). By using an alkyl(meth)acrylate whose homopolymer (homopolymer) has a glass transition temperature (Tg) within the above range as the alkyl(meth)acrylate (a2) that can be contained in the monomer component (M2), the adhesive properties and low elasticity of the acrylic polymer (P2) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0135] Here, with regard to the glass transition temperature Tg of a homopolymer of alkyl (meth)acrylate (a2) that may be contained in the monomer component (M2), the explanation of the glass transition temperature Tg of a homopolymer of alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0136] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) preferably contains an alkyl (meth)acrylate (a2-1) whose homopolymer has a glass transition temperature Tg in the range of −40° C. to −10° C. (preferably −35° C. to −15° C., more preferably −30° C. to −20° C.) Inclusion of the alkyl (meth)acrylate (a2-1) in the alkyl (meth)acrylate (M2) allows the effects of the present invention to be further enhanced.

[0137] An example of the alkyl(meth)acrylate (a2-1) is lauryl acrylate (LA) (the glass transition temperature Tg of its homopolymer is −23° C.).

[0138] The content of alkyl (meth)acrylate (a2-1) in the total amount of alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) is preferably 1 to 30% by weight, more preferably 2 to 20% by weight, even more preferably 4 to 15% by weight, particularly preferably 5 to 12% by weight, and most preferably 6 to 10% by weight, in order to further exhibit the effects of the present invention.

[0139] The content of the alkyl (meth)acrylate (a2-1) in the total amount of the monomer component (M2) is preferably 1 to 30% by weight, more preferably 2 to 20% by weight, even more preferably 4 to 15% by weight, particularly preferably 5 to 12% by weight, and most preferably 6 to 10% by weight, in order to further exhibit the effects of the present invention.

[0140] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) preferably contains an alkyl (meth)acrylate (a2-2) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.). When the alkyl (meth)acrylate (M2) contains the alkyl (meth)acrylate (a2-2), the effects of the present invention can be further enhanced.

[0141] An example of the alkyl(meth)acrylate (a2-2) is 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer is −70° C.).

[0142] The content of alkyl (meth)acrylate (a2-2) in the total amount of alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) is preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, even more preferably 55% by weight to 85% by weight, particularly preferably 60% by weight to 80% by weight, and most preferably 65% ​​by weight to 75% by weight, in order to further exhibit the effects of the present invention.

[0143] The content of the alkyl (meth)acrylate (a2-2) in the total amount of the monomer component (M2) is preferably 40% by weight to 95% by weight, more preferably 50% by weight to 90% by weight, even more preferably 55% by weight to 85% by weight, particularly preferably 60% by weight to 80% by weight, and most preferably 65% ​​by weight to 75% by weight, in order to further exhibit the effects of the present invention.

[0144] In order to further exert the effects of the present invention, the alkyl(meth)acrylate (a2) that can be contained in the monomer component (M2) preferably contains an alkyl(meth)acrylate (a2-3) whose homopolymer has a glass transition temperature Tg in the range of more than -60°C and less than -40°C.

[0145] An example of the alkyl(meth)acrylate (a2-3) is n-butyl acrylate (BA) (the glass transition temperature Tg of its homopolymer is −55° C.).

[0146] The content of the alkyl (meth)acrylate (a2-3) in the total amount of alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) is preferably 1 to 50% by weight, more preferably 5 to 35% by weight, even more preferably 10 to 30% by weight, particularly preferably 13 to 28% by weight, and most preferably 15 to 25% by weight, in order to further exhibit the effects of the present invention.

[0147] The content of the alkyl (meth)acrylate (a2-3) in the total amount of the monomer component (M2) is preferably 1 to 50% by weight, more preferably 5 to 35% by weight, even more preferably 10 to 30% by weight, particularly preferably 13 to 28% by weight, and most preferably 15 to 25% by weight, in order to further exhibit the effects of the present invention.

[0148] [1-2-2-2. Polar group-containing monomer (b2)] The content of the polar group-containing monomer (b2) in the monomer component (M2) is preferably 0.1 to 30% by weight, more preferably 0.5 to 20% by weight, even more preferably 0.8 to 10% by weight, still more preferably 0.8 to 7% by weight, particularly preferably 1 to 5% by weight, and most preferably 1 to 3% by weight, in order to further exert the effects of the present invention.

[0149] In order to further exert the effects of the present invention, the polar group-containing monomer (b2) preferably includes at least one selected from the group consisting of a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, and more preferably includes both a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group.

[0150] The hydroxyl group-containing monomer (b2-1) may be of one type only, or of two or more types.

[0151] For the hydroxyl group-containing monomer (b2-1), the explanation for the hydroxyl group-containing monomer (b1-1) in the section [1-2-1-2. Polar group-containing monomer (b1)] can be cited.

[0152] In order to further enhance the effects of the present invention, the hydroxyl-containing monomer (b2-1) preferably has a glass transition temperature (Tg) of its homopolymer of -60°C to -10°C, more preferably -55°C to -10°C, and even more preferably -45°C to -10°C. The glass transition temperature (Tg) of the homopolymer of the hydroxyl-containing monomer (b2-1) can affect the adhesive properties and low elasticity of the acrylic polymer (P2). By using a hydroxyl-containing monomer whose homopolymer has a glass transition temperature (Tg) within the above range as the hydroxyl-containing monomer (b2-1) that can be contained in the monomer component (M2), the adhesive properties and low elasticity of the acrylic polymer (P2) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0153] With regard to the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b2-1), the explanation of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0154] In terms of further exerting the effects of the present invention, the hydroxyl group-containing monomer (b2-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C).

[0155] The content of the hydroxyl group-containing monomer (b2-1) in the polar group-containing monomer (b2) is preferably 1 to 99% by weight, more preferably 20 to 90% by weight, even more preferably 40 to 80% by weight, particularly preferably 45 to 75% by weight, and most preferably 50 to 70% by weight, in order to further exhibit the effects of the present invention.

[0156] The content of the hydroxyl group-containing monomer (b2-1) in the monomer component (M2) is preferably 0.001 to 10% by weight, more preferably 0.01 to 5% by weight, even more preferably 0.05 to 3% by weight, particularly preferably 0.1 to 2% by weight, and most preferably 0.5 to 1.5% by weight, in order to further exhibit the effects of the present invention.

[0157] The monomer (b2-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0158] For the monomer (b2-2) having a polar group other than a hydroxyl group, the explanation for the monomer (b1-2) having a polar group other than a hydroxyl group in the section [1-2-1-2. Polar group-containing monomer (b1)] can be cited.

[0159] In order to further enhance the effects of the present invention, the glass transition temperature Tg of the homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group is preferably −30°C to 100°C, more preferably −20°C to 95°C, and even more preferably −10°C to 90°C. The glass transition temperature Tg of the homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group can affect the adhesive properties and low elasticity of the acrylic polymer (P2). By using a monomer having a polar group other than a hydroxyl group (b2-2) whose homopolymer has a glass transition temperature Tg within the above range as the monomer having a polar group other than a hydroxyl group that can be contained in the monomer component (M2), the adhesive properties and low elasticity of the acrylic polymer (P2) can be appropriately adjusted, thereby further enhancing the effects of the present invention.

[0160] As the monomer (b2-2) having a polar group other than a hydroxyl group, a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg of 50° C. to 100° C. is preferred, as it can further exhibit the effects of the present invention. The glass transition temperature Tg of the homopolymer of this monomer is preferably 60° C. to 95° C., and more preferably 70° C. to 90° C.

[0161] With regard to the glass transition temperature Tg of a homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group, the explanation of the glass transition temperature Tg of a homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [1-2-1-1. Alkyl (meth)acrylate (a1)] may be cited.

[0162] In order to further enhance the effects of the present invention, the monomer (b2-2) having a polar group other than a hydroxyl group is preferably N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80°C).

[0163] The content of the monomer (b2-2) having a polar group other than a hydroxyl group in the polar group-containing monomer (b2) is preferably 1 to 99% by weight, more preferably 10 to 80% by weight, even more preferably 20 to 60% by weight, particularly preferably 25 to 55% by weight, and most preferably 30 to 50% by weight, in order to further exhibit the effects of the present invention.

[0164] The content of the monomer (b2-2) having a polar group other than a hydroxyl group in the monomer component (M2) is preferably 0.0001 to 10% by weight, more preferably 0.005 to 5% by weight, even more preferably 0.01 to 3% by weight, particularly preferably 0.05 to 2% by weight, and most preferably 0.1 to 1% by weight, in order to further exhibit the effects of the present invention.

[0165] In order to further exert the effects of the present invention, the monomer component (M2) preferably contains an alkyl(meth)acrylate (a2) and at least one selected from the group consisting of a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, more preferably an alkyl(meth)acrylate (a2), a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group, and further preferably a monomer having a glass transition temperature Tg of a homopolymer thereof of −40° C. to −10° C. (preferably −35° C. to −15° C., alkyl(meth)acrylate (a2-1) having a glass transition temperature Tg in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), alkyl(meth)acrylate (a2-2) having a glass transition temperature Tg of the homopolymer of the alkyl(meth)acrylate (a2-3) having a glass transition temperature Tg of more than -60°C but less than -40°C, hydroxyl group-containing monomer (b2-1), and monomer (b2-2) having a polar group other than a hydroxyl group.

[0166] In terms of being able to further exert the effects of the present invention, the monomer component (M2) preferably contains an alkyl(meth)acrylate (a2-1) whose homopolymer has a glass transition temperature Tg in the range of −40° C. to −10° C. (preferably −35° C. to −15° C., more preferably −30° C. to −20° C.), an alkyl(meth)acrylate (a2-2) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.), and an alkyl(meth)acrylate (a2-3) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.). The total content of the alkyl (meth)acrylate (a2-3), the hydroxyl group-containing monomer (b2-1), and the monomer (b2-2) having a polar group other than a hydroxyl group, whose glass transition temperature Tg of the copolymer (homopolymer) is in the range of more than -60°C and less than -40°C, is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0167] In terms of being able to further exert the effects of the present invention, the monomer component (M2) specifically preferably includes lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, n-butyl acrylate, and N-vinyl-2-pyrrolidone.

[0168] [1-2-2-3. Other Monomers (c2)] The monomer component (M2) may contain another monomer (c2) that does not fall into either the alkyl (meth)acrylate (a2) or the polar group-containing monomer (b2). The other monomer (c2) can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (P2), adjusting the adhesive properties, etc. The other monomer may be one type or two or more types.

[0169] The content of other monomers (c2) in the monomer component (M2) is preferably 20% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0170] [1-2-2-4. Thermal polymerization initiator] The thermal polymerization initiator can be appropriately selected from any appropriate thermal polymerization initiator depending on the type of polymerization method, and the thermal polymerization initiator may be one type or two or more types.

[0171] Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, and 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride. hydrochloride, azo initiators such as 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl) peroxydicarbonate, di Examples of initiators include peroxide initiators such as (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; redox initiators that combine peroxides with reducing agents, such as combinations of persulfates and sodium hydrogen sulfite, and combinations of peroxides and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0172] The amount of the thermal polymerization initiator used can be set to any appropriate amount as long as the effects of the present invention are not impaired. The amount of the thermal polymerization initiator used is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, even more preferably 0.007 to 3 parts by weight, and particularly preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the monomer component (M2), in order to further exhibit the effects of the present invention.

[0173] <1-2-3. Photocurable acrylic pressure-sensitive adhesive composition and photocurable acrylic pressure-sensitive adhesive> One embodiment of the acrylic pressure-sensitive adhesive is a photocurable acrylic pressure-sensitive adhesive, which is typically formed by a photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P1).

[0174] The photocurable acrylic pressure-sensitive adhesive is formed from the photocurable acrylic pressure-sensitive adhesive composition by any appropriate method. A typical example of such a formation method is a method in which the photocurable acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, and then another appropriate substrate is placed on the surface of the pressure-sensitive adhesive layer formed by the application, followed by curing by irradiating with ultraviolet light. Examples of the substrate include the aforementioned release liner. The photocurable acrylic pressure-sensitive adhesive composition can be applied by any appropriate application method as long as it does not impair the effects of the present invention. Examples of such application methods include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0175] When forming the photocurable acrylic pressure-sensitive adhesive, heating may be performed as necessary. Furthermore, aging may be performed for the purpose of adjusting component migration in the formed photocurable acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and alleviating distortion that may exist in the photocurable acrylic pressure-sensitive adhesive.

[0176] [1-2-3-1. Crosslinking agent (L1)] The photocurable acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L1). The crosslinking agent (L1) may be one kind or two or more kinds.

[0177] The content of the crosslinking agent (L1) in the photocurable acrylic pressure-sensitive adhesive composition can be set to any appropriate content as long as the effects of the present invention are not impaired. The content of the crosslinking agent (L1) in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, even more preferably 0.01 to 0.2 parts by weight, and particularly preferably 0.05 to 0.1 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1), in order to further exhibit the effects of the present invention.

[0178] As the crosslinking agent (L1), any appropriate crosslinking agent can be used as long as it does not impair the effects of the present invention. As such a crosslinking agent (L1), preferably, a polyfunctional (meth)acrylate is used.

[0179] As the polyfunctional (meth)acrylate, any appropriate polyfunctional (meth)acrylate can be used as long as it does not impair the effects of the present invention. The polyfunctional (meth)acrylate may be one type only or two or more types. Specific examples of such polyfunctional (meth)acrylates include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6- Examples of the ester compound include ester compounds of polyhydric alcohols and (meth)acrylic acid, such as hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylate; vinyl (meth)acrylate; divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl di(meth)acrylate; and hexyl di(meth)acrylate.

[0180] [1-2-3-2. Acrylic oligomer] The photocurable acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer, and the acrylic oligomer may be one kind or two or more kinds.

[0181] The content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition can be set to any appropriate content as long as the effects of the present invention are not impaired. In order to further exhibit the effects of the present invention, the content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, even more preferably 3 to 10 parts by weight, and particularly preferably 5 to 8 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1).

[0182] The weight average molecular weight of the acrylic oligomer is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, still more preferably 1,500 to 10,000, and particularly preferably 2,000 to 8,000. When the photocurable acrylic pressure-sensitive adhesive composition contains an acrylic oligomer, the effects of the present invention can be more effectively exhibited.

[0183] The weight-average molecular weight (Mw) can be determined in terms of polystyrene by the GPC method. For example, it can be measured under the following conditions using a high-speed GPC device "HPLC-8120GPC" manufactured by Tosoh Corporation. Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000 Solvent: tetrahydrofuran Flow rate: 0.6ml / min

[0184] The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C to 300°C, more preferably 30°C to 300°C, and even more preferably 40°C to 300°C.

[0185] The Tg of an acrylic oligomer refers to the value calculated from the Fox formula based on the Tg of a homopolymer of each monomer constituting the acrylic oligomer and the weight fraction (copolymerization ratio by weight) of the monomer. The explanation in <1-2-1. Acrylic polymer (P1)> section can be used for the Fox formula and the Tg of various homopolymers.

[0186] The acrylic oligomer is preferably an acrylic oligomer obtained from a monomer composition containing, as an essential component, a (meth)acrylic acid ester having a cyclic structure in the molecule, and more preferably an acrylic oligomer obtained from a monomer composition containing, as essential components, a (meth)acrylic acid ester having a cyclic structure in the molecule and a (meth)acrylic acid alkyl ester having a linear or branched alkyl group.

[0187] The (meth)acrylic acid ester having a cyclic structure in the molecule may be of one type only, or of two or more types.

[0188] The (meth)acrylic acid alkyl ester having a linear or branched alkyl group may be of one type only, or of two or more types.

[0189] The cyclic structure in the (meth)acrylic acid ester having a cyclic structure in the molecule may be either an aromatic ring or a non-aromatic ring.

[0190] Examples of aromatic rings include aromatic carbocycles (for example, monocyclic carbocycles such as a benzene ring, and fused carbocycles such as a naphthalene ring), and various aromatic heterocycles.

[0191] Examples of non-aromatic rings include non-aromatic aliphatic rings (non-aromatic alicyclic rings) (e.g., cycloalkane rings such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; cycloalkene rings such as cyclohexene), non-aromatic bridged rings (e.g., bicyclic hydrocarbon rings such as pinane, pinene, bornane, norbornane, and norbornene; tricyclic or higher aliphatic hydrocarbon rings (bridged hydrocarbon rings) such as adamantane), and non-aromatic heterocycles (e.g., epoxy rings, oxolane rings, and oxetane rings). Examples of tricyclic or higher aliphatic hydrocarbon rings (tricyclic or higher bridged hydrocarbon rings) include dicyclopentanyl, dicyclopentenyl, adamantyl, tricyclopentanyl, and tricyclopentenyl groups.

[0192] Specific examples of the (meth)acrylic acid ester having a cyclic structure in the molecule include (meth)acrylic acid cycloalkyl esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1- Examples include (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings, such as adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate; (meth)acrylic acid esters having an aromatic ring, such as (meth)acrylic acid aryl esters, such as phenyl (meth)acrylate; (meth)acrylic acid aryloxyalkyl esters, such as phenoxyethyl (meth)acrylate; and (meth)acrylic acid arylalkyl esters, such as benzyl (meth)acrylate.

[0193] As the (meth)acrylic acid ester having a cyclic structure in the molecule, a non-aromatic ring-containing (meth)acrylic acid ester is preferred, in terms of being able to further exhibit the effects of the present invention, more preferred are cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclopentanyl acrylate (DCPA), and dicyclopentanyl methacrylate (DCPMA), and even more preferred are dicyclopentanyl acrylate (DCPA) and dicyclopentanyl methacrylate (DCPMA).

[0194] The content of the (meth)acrylic acid ester having a cyclic structure in the molecule of all the monomers that can be used to constitute the acrylic oligomer is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, relative to 100 parts by weight of all the monomers, in order to further exhibit the effects of the present invention.

[0195] Examples of (meth)acrylic acid alkyl esters having a linear or branched alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and methyl (meth)acrylate. Examples of suitable (meth)acrylic acid alkyl esters include those in which the alkyl group has 1 to 20 carbon atoms, such as isooctyl, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, methyl methacrylate (MMA) is preferred in that it can further exert the effects of the present invention.

[0196] The content of the (meth)acrylic acid alkyl ester having a linear or branched alkyl group in all monomers that can be used to constitute the acrylic oligomer is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and even more preferably 20 to 60 parts by weight, relative to 100 parts by weight of all monomers, in order to further exhibit the effects of the present invention.

[0197] The total monomers (monomer composition) that can be used to form the acrylic oligomer may contain, in addition to the (meth)acrylic acid ester having a cyclic structure in the molecule and the (meth)acrylic acid alkyl ester having a linear or branched alkyl group, other monomers (copolymerizable monomers) that can be copolymerized with these monomers. The content of the other monomers (copolymerizable monomers) in the total monomers (monomer composition) that can be used to form the acrylic oligomer is preferably less than 50 parts by weight, more preferably 40 parts by weight or less, even more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less, relative to 100 parts by weight of the total monomers.

[0198] Examples of such other monomers (copolymerizable monomers) include (meth)acrylic acid alkoxyalkyl esters (e.g., 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-ethoxybutyl (meth)acrylate, etc.), carboxyl group-containing monomers (e.g., acid anhydride group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, etc.), hydroxyl group-containing monomers (e.g., hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc.); vinyl alcohol; allyl alcohol; etc.), amide group-containing monomers (e.g., (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, etc.), amino group-containing monomers (e.g., aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, etc.), cyano group-containing monomers (e.g., acrylonitrile, methacrylonitrile, etc.), sulfonic acid group-containing monomers (e.g., sodium vinyl sulfonate, etc.), phosphoric acid group-containing monomers (e.g., 2-hydroxyethyl acryloyl phosphate, etc.), isocyanate group-containing monomers (e.g., 2-methacryloyloxyethyl isocyanate, etc.), imide group-containing monomers (e.g., cyclohexylmaleimide, isopropylmaleimide, etc.).

[0199] The total monomers (monomer composition) that can be used to form the acrylic oligomer particularly preferably contain (1) at least one monomer selected from dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and (2) methyl methacrylate. In this case, the content of the monomer (1) is preferably 30 to 70 parts by weight, and the content of the monomer (2) is preferably 30 to 70 parts by weight, relative to 100 parts by weight of the total monomers (monomer composition) that can be used to form the acrylic oligomer.

[0200] The acrylic oligomer can be produced by any suitable polymerization method as long as the effects of the present invention are not impaired. Examples of such polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). Among these, bulk polymerization and solution polymerization are preferred, and solution polymerization is more preferred.

[0201] Examples of solvents that can be used in the polymerization include organic solvents such as 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, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one type of solvent may be used, or two or more types may be used.

[0202] In the polymerization, any appropriate polymerization initiator (for example, a thermal polymerization initiator or a photopolymerization initiator) can be used as long as it does not impair the effects of the present invention. The polymerization initiator may be one type or two or more types. When solution polymerization is performed, it is preferable to use an oil-soluble polymerization initiator.

[0203] As the thermal polymerization initiator, any appropriate thermal polymerization initiator can be used as long as it does not impair the effects of the present invention. The thermal polymerization initiator may be one type or two or more types. For specific examples of such thermal polymerization initiators, the explanation in the section [1-2-2-4. Thermal polymerization initiator] can be cited.

[0204] The content of the thermal polymerization initiator is, for example, preferably 0.1 to 15 parts by weight relative to 100 parts by weight of all the monomers (monomer composition) that can be used to form the acrylic oligomer.

[0205] As the photopolymerization initiator, any appropriate photopolymerization initiator may be used as long as it does not impair the effects of the present invention. The photopolymerization initiator may be one type or two or more types. For specific examples of such photopolymerization initiators, the explanation in the section [1-2-1-4. Photopolymerization initiator] may be cited.

[0206] The content of the photopolymerization initiator is preferably 0.001 to 0.5 parts by weight, for example, relative to 100 parts by weight of all monomers (monomer composition) that can be used to form the acrylic oligomer.

[0207] During polymerization of the acrylic oligomer, a chain transfer agent may be used to adjust the molecular weight (preferably to adjust the weight average molecular weight to 1,000 to 30,000). Examples of the chain transfer agent include 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-1-propanol, octyl mercaptan, t-nonyl mercaptan, dodecyl mercaptan (lauryl mercaptan), t-dodecyl mercaptan, glycidyl mercaptan, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycolic acid esters of ethylene glycol, thioglycolic acid esters of neopentyl glycol, thioglycolic acid esters of pentaerythritol, and α-methylstyrene dimer. Among these, from the viewpoint of suppressing whitening of the double-sided pressure-sensitive adhesive tape of the present invention, α-thioglycerol and methyl thioglycolate are preferred, and α-thioglycerol is particularly preferred. Only one type of chain transfer agent may be used, or two or more types may be used.

[0208] The content of the chain transfer agent is, for example, preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight, relative to 100 parts by weight of all monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0209] [1-2-3-3. Other ingredients] The photocurable acrylic pressure-sensitive adhesive composition may contain any appropriate other components within the scope of not impairing the effects of the present invention, such as tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foil-like materials, softeners, antioxidants, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, crosslinking retarders, etc.

[0210] <1-2-4. Thermosetting acrylic pressure-sensitive adhesive composition and thermosetting acrylic pressure-sensitive adhesive> One embodiment of the acrylic pressure-sensitive adhesive is a thermosetting acrylic pressure-sensitive adhesive, which is typically formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P2).

[0211] The thermosetting acrylic pressure-sensitive adhesive is formed from the thermosetting acrylic pressure-sensitive adhesive composition by any appropriate method. A typical example of such a formation method is a method in which the thermosetting acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, heated and dried as necessary, and cured as necessary to form a sheet of the thermosetting acrylic pressure-sensitive adhesive on the substrate. Any coating method can be used as long as it does not impair the effects of the present invention. Examples of such coating methods include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0212] The thermosetting acrylic pressure-sensitive adhesive composition may be heated and dried by any appropriate means as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to approximately 60°C to 180°C. The thermosetting acrylic pressure-sensitive adhesive composition may be cured by any appropriate means as long as the effects of the present invention are not impaired. Examples of such curing means include ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0213] When forming the thermosetting acrylic pressure-sensitive adhesive, aging may be carried out as necessary for the purpose of adjusting component migration within the formed thermosetting acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and alleviating distortion that may exist within the photocurable acrylic pressure-sensitive adhesive.

[0214] [1-2-4-1. Crosslinking agent (L2)] The thermosetting acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L2). The crosslinking agent (L2) may be one kind or two or more kinds.

[0215] The use of the crosslinking agent (L2) can impart appropriate cohesive strength to the thermosetting acrylic pressure-sensitive adhesive. The crosslinking agent (L2) can be contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction, a form before crosslinking reaction, a partially crosslinked form, or an intermediate or composite form thereof. The crosslinking agent (L2) is typically contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction.

[0216] The content of the crosslinking agent (L2) in the thermosetting acrylic pressure-sensitive adhesive composition is preferably 0.005 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, even more preferably 0.01 to 3 parts by weight, still more preferably 0.01 to 1 part by weight, even more preferably 0.01 to 0.7 parts by weight, still more preferably 0.01 to 0.5 parts by weight, particularly preferably 0.01 to 0.4 parts by weight, and most preferably 0.01 to 0.1 parts by weight, relative to 100 parts by weight of the acrylic polymer (P2), in order to further exhibit the effects of the present invention.

[0217] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, an alkyl etherified melamine-based crosslinking agent, a metal chelate-based crosslinking agent, and a peroxide. In terms of being able to further exhibit the effects of the present invention, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a peroxide is preferred, and an isocyanate-based crosslinking agent or a peroxide is more preferred.

[0218] The isocyanate crosslinking agent can be a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which the isocyanate group is temporarily protected by a blocking agent or oligomerization) per molecule. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0219] Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL). Examples of suitable polyisocyanates include isocyanate adducts such as those manufactured by Mitsui Chemicals under the trade name of Coronate HX; trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D140N), and trimethylolpropane adducts of hexamethylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred because they can achieve a good balance between deformability and cohesive strength.

[0220] As the epoxy-based crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)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, and sorbitol polyglycidyl ether. Examples of epoxy crosslinking agents include 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, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Commercially available epoxy crosslinking agents include, for example, "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0221] Examples of peroxides include dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxin)hexyne-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-butylperoxy-2-ethylhexyl carbonate, t-amylperoxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butyl peroxypivalate, and t-hexyl peroxypivalate. Commercially available peroxides include, for example, the "Niper BMT" series and "Niper BW" series manufactured by Nippon Oil & Fats Corporation.

[0222] [1-2-4-2. Acrylic oligomer] The thermosetting acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer may be one type only or two or more types. For the acrylic oligomer, the explanation in the section [1-2-3-2. Acrylic Oligomer] may be used.

[0223] [1-2-4-3. Other ingredients] The thermosetting acrylic pressure-sensitive adhesive composition may contain any appropriate other components within the scope of not impairing the effects of the present invention, such as tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foil-like materials, softeners, antioxidants, conductive agents, UV absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, crosslinking retarders, etc.

[0224] ≪≪2. Uses of reinforcing film≫≫ The reinforcing film according to the embodiment of the present invention can be used for any suitable application. The surface protection film of the present invention is preferably used, for example, to reinforce optical components and electronic components. Examples of optical components include LCDs, touch panels using LCDs, color filters used in LCDs, polarizing plates, and the like.

[0225] That is, an optical member according to an embodiment of the present invention has the reinforcing film of the present invention attached thereto, and an electronic member according to an embodiment of the present invention has the reinforcing film of the present invention attached thereto.

[0226] The optical and electronic components may be flexible devices such as bendable devices (devices that can be bent) having movable bending parts, foldable devices (devices that can be folded), or rollable devices (devices that can be rolled up). [Example]

[0227] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0228] The abbreviations and details of raw materials used in the following Production Examples, Examples, and Comparative Examples are as follows: 2EHA: 2-ethylhexyl acrylate (glass transition temperature of its homopolymer, Tg = -70°C) LA: Lauryl acrylate (glass transition temperature of its homopolymer, Tg = -23°C) BA: n-butyl acrylate (glass transition temperature of its homopolymer, Tg = -55°C) 4HBA: 4-hydroxybutyl acrylate (glass transition temperature of its homopolymer, Tg = -32°C) NVP: N-vinyl-2-pyrrolidone (glass transition temperature of its homopolymer: Tg = 80°C) MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate AIBN: 2,2'-azobisisobutyronitrile Omnirad184: Photopolymerization initiator (manufactured by IGM Resins) A-HD-N: 1,6-hexanediol diacrylate (HDDA) (manufactured by Shin-Nakamura Chemical Co., Ltd.) BPO: Product name "Niper BW" (peroxide, manufactured by NOF Corporation)

[0229] <Surface elastic modulus of adhesive layer at 25°C> The release liner was peeled off from the obtained reinforced film, and the thickness was measured using an AFM by the following method. 1) A sample of approximately 5 mm x 10 mm was cut out and fixed on a designated sample stand. 2) The spring constant used to calculate the surface elastic modulus was the value specified by the manufacturer. 3) The sensitivity coefficient was determined using a silicon wafer. 4) Before measurement, static electricity was removed, and force curve mapping measurements were performed at 16 x 16 points in an area of ​​50 μm square (50 μm long x 50 μm wide) using an AFM. 5) The obtained force curve was converted into a load-displacement curve using the spring constant and sensitivity coefficient in 2) and 3) above. 6) Using the load-displacement curve in 5) above, the surface elastic modulus was calculated by the JKR two-point method. 7) A histogram of 256 data points was created from the obtained mapping image of the surface elastic modulus, and a Gaussian fit was performed. 8) The Gaussian-fitted peak value was read as the value of the surface elastic modulus. Device: Oxford Instruments, Asylum Research MFP-3D-SA Measurement mode: AFM force curve mapping (16×16 points), speed 2 Hz Cantilever: NANOSENSORS, SD-R150-FM (Si-made, equivalent to a spring constant of 2.8 N / m) Measurement range: 50 μm Measurement atmosphere: Under atmospheric pressure Measurement temperature: 25 °C

[0230] <MD direction heat shrinkage rate> The heat shrinkage rate in the MD direction (longitudinal direction) of the reinforcing film was calculated as follows. Specifically, the reinforcing film with the release liner attached was cut into a size of 100 mm in width and 100 mm in length to obtain a test piece. The length (mm) in the MD direction was measured by a non-contact displacement sensor-equipped image measuring machine Quick vision (manufactured by Mitutoyo). After that, the release liner was peeled off, and the test piece was placed with the adhesive layer facing up, and heat treatment (180 °C, 5 minutes) was performed. After cooling at room temperature for 1 hour, the length (mm) in the MD direction was measured again by the non-contact displacement sensor-equipped image measuring machine Quick vision (manufactured by Mitutoyo), and the MD direction heat shrinkage rate was obtained by substituting the measured value into the following formula. MD direction heat shrinkage rate (%) = [(length before heating (mm) - length after heating (mm)) / length before heating (mm)] × 100

[0231] <Adhesive force at 25 °C to the polyimide film> A polyimide film with a thickness of 25 μm (manufactured by Ube Industries, "Upilex S") was attached to a glass plate through a double-sided adhesive tape (manufactured by Nitto Denko, "No. 531") to obtain a polyimide film substrate for measurement. The release liner was peeled off from the surface of the reinforcing film cut into a width of 25 mm × a length of 100 mm, and it was bonded to the polyimide film substrate for measurement using a hand roller to prepare a sample for measuring the adhesive force. After lamination, the film was left at 25°C for 1 day, and then the end of the base layer of the reinforced film was held with a chuck, and a 180° peel test was performed on the reinforced film at a tensile speed of 300 mm / min in a 25°C environment to measure the peel strength, and the obtained peel strength was defined as the adhesive strength to the polyimide film at 25°C.

[0232] <Adhesion strength to polyimide film at -20°C> A 25 μm thick polyimide film (Ube Industries, "Upilex S") was attached to a glass plate via double-sided adhesive tape (Nitto Denko, "No. 531") to obtain a polyimide film substrate for measurement. The release liner was peeled off from the surface of a reinforcing film cut to a width of 25 mm and a length of 100 mm, and the film was then attached to a polyimide film substrate for measurement using a hand roller to prepare a sample for measuring adhesive strength. After lamination, the film was left at 25°C for 1 day, and then the end of the base layer of the reinforced film was held with a chuck, and a 180° peel test was performed on the reinforced film at a tensile speed of 300 mm / min in an environment of -20°C to measure the peel strength, and the obtained peel strength was defined as the adhesive strength to the polyimide film at -20°C.

[0233] <Adhesion strength to polyimide film at 180°C> A 25 μm thick polyimide film (Ube Industries, "Upilex S") was attached to a glass plate via double-sided adhesive tape (Nitto Denko, "No. 531") to obtain a polyimide film substrate for measurement. The release liner was peeled off from the surface of a reinforcing film cut to a width of 25 mm and a length of 100 mm, and the film was then attached to a polyimide film substrate for measurement using a hand roller to prepare a sample for measuring adhesive strength. After lamination, the film was left at 25°C for 1 day, and then the end of the base layer of the reinforced film was held with a chuck, and a 180° peel test was performed on the reinforced film at a tensile speed of 300 mm / min in an environment of 180°C to measure the peel strength, which was used as the adhesive strength to the polyimide film at 180°C.

[0234] <Transmittance at a wavelength of 550 nm> The transmittance of the prepared reinforcing film at 550 nm was measured using a spectrophotometer (manufactured by Hitachi, Ltd., model: U-4100).

[0235] <Storage modulus G' of adhesive layer at -20°C> [Sample Preparation Method 1 (Examples 3 to 5, 7 to 8, 11 to 13, 15 to 16, Comparative Examples 3 to 5, 7 to 12)] The adhesive composition was applied to the release-treated surface of a 75 μm-thick polyester film (trade name "Diafoil MRF75", manufactured by Mitsubishi Chemical Corporation) with one side treated for release with silicone using a fountain roll so that the dried thickness would be 25 μm, and the film was cured and dried at a drying temperature of 130°C for 1 minute. In this way, an adhesive layer was produced on the substrate. Next, a 75 μm-thick polyester film (trade name "Diafoil MRF75", manufactured by Mitsubishi Chemical Corporation) with one side treated for release with silicone was coated on the surface of the adhesive layer, with the release-treated surface of the polyester film facing the adhesive layer, and the film was aged at 50°C for 1 day to produce a 25 μm-thick adhesive sheet as a sample. [Sample Preparation Method 2 (Examples 1, 2, 6, 9-10, 14, Comparative Examples 1, 2, 6)] A 75 μm thick polyester film (trade name "Diafoil MRF75", manufactured by Mitsubishi Chemical Corporation) with one side treated with silicone for release was used as a substrate (also serving as a heavy release film), and a pressure-sensitive adhesive composition was applied to the substrate to a thickness of 25 μm to form a coating layer. A 75 μm thick polyester film (trade name "Diafoil MRF75", manufactured by Mitsubishi Chemical Corporation) with one side treated with silicone for release was attached to the coating layer as a cover sheet (also serving as a light release film). The laminate was then exposed from the cover sheet side to a lamp with an irradiation intensity of 5 mW / cm2 on the irradiated surface. 2 The adhesive sheet was then photocured by irradiating it with ultraviolet light using a black light whose position was adjusted so that the adhesive sheet was 25 μm thick. [Measurement method] The dynamic viscoelasticity was measured by the following method using a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics). Only the adhesive layer was removed from the obtained sample adhesive sheet, laminated to a thickness of approximately 1 mm, and punched out to a diameter of 8 mm to prepare a cylindrical pellet for use as a measurement sample. The obtained measurement sample was fixed to a diameter 8 mm parallel plate jig, and the storage modulus G' was calculated using the dynamic viscoelasticity measuring device. The measurement conditions were as follows: Measurement: Shear mode Temperature range: -70℃~200℃ Heating rate: 5℃ / min Frequency: 1Hz

[0236] <Tensile modulus of base layer> Both ends of a substrate layer cut into a width of 10 mm and a length of 100 mm were held with chucks, and a peel test was carried out in an environment of 25°C at a pulling rate of 200 mm / min to measure the tensile modulus (in accordance with JIS K7161).

[0237] [Production Example 1]: Production of acrylic polymer A (UV polymerization) The monomer components for forming the prepolymer were 43 parts by weight of lauryl acrylate (LA), 44 parts by weight of 2-ethylhexyl acrylate (2EHA), 6 parts by weight of 4-hydroxybutyl acrylate (4HBA), and 7 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by weight of "Omnirad 184" manufactured by IGM Resins was used as a photopolymerization initiator. Polymerization was carried out by irradiating with ultraviolet light, yielding a solution of acrylic polymer A (prepolymer) (polymerization rate: approximately 10%).

[0238] [Production Example 2]: Production of acrylic polymer B (solution polymerization) A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 70 parts by weight of 2-ethylhexyl acrylate (2-EHA), 20 parts by weight of butyl acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylate (4HBA), 8 parts by weight of lauryl acrylate (LA), and 0.6 parts by weight of N-vinyl-2-pyrrolidone (NVP), 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 120 parts by weight of ethyl acetate as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer B with a weight-average molecular weight of 1.2 million.

[0239] [Production Example 3]: Production of acrylic polymer C (UV polymerization) The monomer components for forming the prepolymer were 34 parts by weight of lauryl acrylate (LA), 56 parts by weight of 2-ethylhexyl acrylate (2EHA), 7 parts by weight of 4-hydroxybutyl acrylate (4HBA), and 2 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 0.015 parts by weight of "Omnirad 184" manufactured by IGM Resins was used as a photopolymerization initiator. Polymerization was carried out by irradiating with ultraviolet light, yielding a solution of acrylic polymer C (prepolymer) (polymerization rate: approximately 10%).

[0240] [Production Example 4]: Production of acrylic polymer D (solution polymerization) A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 65 parts by weight of 2-ethylhexyl acrylate (2-EHA), 15 parts by weight of N-vinyl-2-pyrrolidone (NVP), 12 parts by weight of 2-hydroxyethyl acrylate (HEA), and 8 parts by weight of methyl methacrylate (MMA), 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 120 parts by weight of ethyl acetate as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer D with a weight-average molecular weight of 800,000.

[0241] [Production Example 5]: Production of acrylic polymer E (solution polymerization) A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate (HEA) as monomers, 1.0 part by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 156 parts by weight of ethyl acetate as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 60°C and reacted for 7 hours to obtain a solution of acrylic polymer E with a weight-average molecular weight of 1.6 million.

[0242] [Production Example 6]: Production of acrylic polymer F (solution polymerization) A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 95 parts by weight of butyl acrylate (BA) as monomers, 5 parts by weight of acrylic acid (AA), 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 156 parts by weight of ethyl acetate as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 60°C and reacted for 10 hours to obtain a solution of acrylic polymer F with a weight-average molecular weight of 700,000.

[0243] [Production Example 7]: Production of acrylic oligomer A A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 62 parts by weight of dicyclopentanyl methacrylate (DCPMA) and 38 parts by weight of methyl methacrylate (MMA) as monomers, 3.5 parts by weight of methyl thioglycolate as a chain transfer agent, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 100 parts by weight of toluene as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 70°C and reacted for 2 hours, then at 80°C for 4 hours, and then at 90°C for 1 hour, yielding a solution of acrylic oligomer A with a weight-average molecular weight of 4000.

[0244] [Production Example 8]: Production of acrylic oligomer B A reaction vessel equipped with a thermometer, stirrer, reflux condenser, and nitrogen gas inlet tube was charged with 96 parts by weight of cyclohexyl methacrylate (CHMA) and 4 parts by weight of acrylic acid (AA) as monomers, 3 parts by weight of 2-mercaptoethanol as a chain transfer agent, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 103.2 parts by weight of toluene as a solvent. Nitrogen gas was introduced and the mixture was purged with nitrogen for approximately 1 hour while stirring. The mixture was then heated to 70°C and reacted for 3 hours, and then further reacted at 75°C for 2 hours to obtain a solution of acrylic oligomer B with a weight-average molecular weight of 4000.

[0245] [Example 1] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed polyethylene terephthalate film (hereinafter sometimes referred to as annealed PET film) was produced by heat-treating a 50 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical, product name "T100C50") that had not been surface-treated at 200°C for 5 minutes. (Preparation of Pressure-Sensitive Adhesive Composition (1)) To 100 parts by weight of acrylic polymer A, 0.08 parts by weight of 1,6-hexanediol diacrylate (HDDA) (trade name "A-HD-N", manufactured by Shin-Nakamura Chemical Co., Ltd.) and 6 parts by weight of acrylic oligomer A were added as post-added components, and then these were mixed uniformly to prepare pressure-sensitive adhesive composition (1). (Preparation of adhesive sheet) A 75 μm thick polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical, trade name "Diafoil MRF75") with a silicone-based release layer on its surface was used as a substrate (doubles as a heavy-duty release film), and the above-mentioned pressure-sensitive adhesive composition (1) was applied to the substrate to a thickness of 15 μm to form a coating layer. Onto this coating layer, a 75 μm thick PET film (manufactured by Mitsubishi Chemical, trade name "Diafoil MRE75") with one side treated with silicone release was attached as a cover sheet (doubles as a light-duty release film). The resulting laminate was then exposed to light from the cover sheet side at an irradiation intensity of 5 mW / cm2 on the irradiated surface directly below the lamp. 2The adhesive sheet was then photocured by irradiating it with ultraviolet light using a black light whose position was adjusted so that the adhesive sheet was 15 μm thick. (Preparation of Reinforcement Film (1)) The light release film of the obtained pressure-sensitive adhesive sheet was peeled off and the sheet was stuck onto an annealed PET film as a substrate to prepare a reinforcing film (1). The various results are shown in Table 1.

[0246] [Example 2] A reinforcing film (2) was produced in the same manner as in Example 1, except that the thickness of the pressure-sensitive adhesive composition after drying was changed to 25 μm. The various results are shown in Table 1.

[0247] [Example 3] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed PET film was prepared in the same manner as in Example 1. (Preparation of Pressure-Sensitive Adhesive Composition (3)) To 100 parts by weight of acrylic polymer B, 6 parts by weight of acrylic oligomer A and 0.38 parts by weight of NOF Corp.'s "Niper BW" (BPO) as a crosslinking agent were added to prepare a pressure-sensitive adhesive composition (3). (Preparation of Reinforcement Film (3)) The pressure-sensitive adhesive composition (3) was applied to annealed PET using a fountain roll so that the thickness after drying would be 15 μm. After drying at 130°C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25 μm-thick polyethylene terephthalate film whose surface was treated with silicone release agent) was attached to the coated surface. After that, an aging treatment was performed for 4 days in an atmosphere at 25°C to promote crosslinking, and a reinforcing film (3) was produced. The various results are shown in Table 1.

[0248] [Example 4] A reinforcing film (4) was produced in the same manner as in Example 3, except that the thickness of the pressure-sensitive adhesive composition after drying was changed to 25 μm. The various results are shown in Table 1.

[0249] [Example 5] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed PET film was prepared in the same manner as in Example 1. (Preparation of Pressure-Sensitive Adhesive Composition (5)) To 100 parts by weight of acrylic polymer B, 1.5 parts by weight of acrylic oligomer B and 0.28 parts by weight of NOF Corp.'s "Niper BW" (BPO) as a crosslinking agent were added to prepare a pressure-sensitive adhesive composition (5). (Preparation of reinforcing film (5)) A reinforcing film (5) was produced in the same manner as in Example 3, except that the pressure-sensitive adhesive composition (3) was changed to the pressure-sensitive adhesive composition (5). The various results are shown in Table 1.

[0250] [Example 6] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed PET film was prepared in the same manner as in Example 1. (Preparation of Pressure-Sensitive Adhesive Composition (6)) To 100 parts by weight of acrylic polymer C, 0.08 parts by weight of 1,6-hexanediol diacrylate (HDDA) (trade name "A-HD-N", manufactured by Shin-Nakamura Chemical Co., Ltd.) and 2 parts by weight of acrylic oligomer A were added as post-added components, and then these were mixed uniformly to prepare a pressure-sensitive adhesive composition (6). (Preparation of adhesive sheet) A 25 μm thick adhesive sheet was prepared in the same manner as in Example 1, except that adhesive composition (6) was used instead of adhesive composition (1) and the thickness of the adhesive composition after drying was changed to 25 μm. (Preparation of reinforcing film (6)) The light release film of the obtained pressure-sensitive adhesive sheet was peeled off and the sheet was stuck onto an annealed PET film to prepare a reinforcing film (6). The various results are shown in Table 1.

[0251] [Example 7] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed PET film was prepared in the same manner as in Example 1. (Preparation of Pressure-Sensitive Adhesive Composition (7)) To 100 parts by weight of acrylic polymer E, 1.5 parts by weight of acrylic oligomer A, 0.3 parts by weight of "Niper BW" (BPO) manufactured by NOF Corp. as a crosslinking agent, and 0.1 parts by weight of a trifunctional isocyanate compound ("Takenate D-110N" manufactured by Mitsui Chemicals Corp.) were added to prepare a pressure-sensitive adhesive composition (7). (Preparation of reinforcing film (7)) The pressure-sensitive adhesive composition (7) was applied to annealed PET using a fountain roll so that the thickness after drying would be 25 μm. After drying at 130°C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25 μm-thick polyethylene terephthalate film whose surface was treated with silicone release agent) was attached to the coated surface. After that, an aging treatment was performed for 4 days in an atmosphere at 25°C to promote crosslinking, and a reinforcing film (7) was produced. The various results are shown in Table 1.

[0252] [Example 8] (Preparation of Annealed Polyethylene Terephthalate Film) An annealed PET film was prepared in the same manner as in Example 1. (Preparation of Pressure-Sensitive Adhesive Composition (8)) A pressure-sensitive adhesive composition (8) was prepared by adding 25 parts by weight of acrylic oligomer B and 0.08 parts by weight of an epoxy compound ("TETRAD-C" manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a crosslinking agent to 100 parts by weight of acrylic polymer F. (Preparation of reinforcing film (8)) The pressure-sensitive adhesive composition (8) was applied to annealed PET using a fountain roll so that the thickness after drying would be 15 μm. After drying at 130°C for 1 minute to remove the solvent, the release-treated surface of a release liner (a 25 μm-thick polyethylene terephthalate film whose surface was treated with silicone release agent) was attached to the coated surface. After that, an aging treatment was performed for 4 days in an atmosphere at 25°C to promote crosslinking, and a reinforcing film (8) was produced. The various results are shown in Table 1.

[0253] [Examples 9 to 16] Reinforced films (9) to (16) were produced in the same manner as in Examples 1 to 8, except that a 50 μm thick polyimide (PI) film (manufactured by Toray DuPont, product name "Kapton 200H") was used as the substrate. The various results are shown in Table 1.

[0254] [Comparative Examples 1 to 6] Reinforced films (C1) to (C6) were produced in the same manner as in Examples 1 to 6, except that a 50 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical, product name "T100C50") that had not been surface-treated was used as the substrate. The various results are shown in Table 1.

[0255] Comparative Example 7 (Preparation of Pressure-Sensitive Adhesive Composition (C7)) A pressure-sensitive adhesive composition (C7) was prepared by adding 0.25 parts by weight of a trifunctional isocyanate compound (manufactured by Mitsui Chemicals, trade name "Takenate D-110N") as a crosslinking agent to 100 parts by weight of acrylic polymer D. (Preparation of adhesive sheet) A 15 μm thick pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the pressure-sensitive adhesive composition (C7) was used instead of the pressure-sensitive adhesive composition (1). (Preparation of Reinforcing Film (C7)) The light release film of the obtained adhesive sheet was peeled off and attached to a 50 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical, product name "T100C50") that had not been surface-treated as a substrate to produce a reinforcing film (C7). The various results are shown in Table 1.

[0256] [Comparative Example 8] A reinforcing film (C8) was produced in the same manner as in Comparative Example 7, except that the thickness of the pressure-sensitive adhesive composition after drying was changed to 25 μm. The various results are shown in Table 1.

[0257] Comparative Example 9 A reinforcing film (C9) was produced in the same manner as in Comparative Example 7, except that an annealed PET film was used as the substrate. The various results are shown in Table 1.

[0258] [Comparative Example 10] A reinforced film (C10) was produced in the same manner as in Comparative Example 8, except that an annealed PET film was used as the substrate. The various results are shown in Table 1.

[0259] [Comparative Example 11] A reinforcing film (C11) was produced in the same manner as in Comparative Example 7, except that a 50 μm-thick polyimide (PI) film (manufactured by DuPont-Toray, trade name "Kapton 200H") was used as the substrate. The various results are shown in Table 1.

[0260] [Comparative Example 12] A reinforcing film (C12) was produced in the same manner as in Comparative Example 8, except that a 50 μm-thick polyimide (PI) film (manufactured by DuPont-Toray, trade name "Kapton 200H") was used as the substrate. The various results are shown in Table 1.

[0261] [Table 1] [Industrial Applicability]

[0262] The reinforcing film according to the embodiment of the present invention is preferably used to reinforce optical members and electronic members, for example. [Explanation of symbols]

[0263] 100 Reinforcement film 10 Base material layer 20 adhesive layer

Claims

1. A reinforced film comprising a base layer and a pressure-sensitive adhesive layer, the material of the base material layer is polyimide or annealed polyethylene terephthalate, the pressure-sensitive adhesive layer is made of an acrylic pressure-sensitive adhesive, the acrylic pressure-sensitive adhesive is a photocurable acrylic pressure-sensitive adhesive formed by a photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition, or a thermosetting acrylic pressure-sensitive adhesive formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition; the pressure-sensitive adhesive layer has a surface elastic modulus of 50 kPa to 1000 kPa at 25°C; Reinforcement film.

2. 2. The reinforced film according to claim 1, which has an adhesive strength to a polyimide film at 25°C of 5.0 N / 25 mm or more.

3. The reinforced film according to claim 1, which has a transmittance of 80% or more at a wavelength of 550 nm.

4. The reinforcing film according to claim 1 , wherein the acrylic adhesive is a photocurable acrylic adhesive.

5. 2. The reinforced film according to claim 1, wherein the pressure-sensitive adhesive layer has a storage modulus G' at -20°C of 80 kPa to 300 kPa.

6. An optical member comprising the reinforcing film according to claim 1 .

7. An electronic component comprising the reinforcing film according to claim 1 .

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