Reinforcement film

Abstract

The present invention provides a reinforcing film comprising a substrate layer and an adhesive layer, wherein excellent low elasticity and excellent heat resistance are compatible, and, for example, IC connection failure is unlikely to occur. The reinforcing film according to an embodiment of the present invention is a reinforcing film comprising a substrate layer and an adhesive layer, wherein the adhesive layer is composed of an acrylic adhesive, the surface elasticity modulus of the adhesive layer at 25°C is 50kPa to 1000kPa, and the MD direction heating shrinkage rate when the reinforcing film is heated at 180°C for 5 minutes is 1.0% or less.

Description

Technology Field

[0001] The present invention relates to a reinforcing film. Background Technology

[0002] Adhesive films are used to reinforce members of various shapes. For example, adhesive films have been reported as reinforcing films that remain attached to the surface of the device even during use, in addition to being used during assembly, processing, and transportation of the device (e.g., Patent Document 1). In addition to surface protection, such adhesive films have the function of reinforcing the device by dispersing impact to the device or imparting rigidity to the flexible device.

[0003] For example, when bonding an integrated circuit (IC) or a flexible printed circuit board (FPC) to a substrate of a semiconductor device (e.g., a TFT substrate, etc.), thermal compression is typically performed using an anisotropic conductive film (ACF). When performing such thermal compression, there are cases where an adhesive film is bonded to the other side of the semiconductor device substrate in advance to provide reinforcement (e.g., Patent Document 2).

[0004] In addition, as a method for manufacturing so-called flexible devices, such as foldable or rollable devices currently under development, a release layer and a flexible film substrate are generally formed on a support substrate such as glass, a TFT substrate is formed on the film substrate, and an organic EL layer is formed thereon. Then, the support substrate is released to manufacture the flexible device, but since the flexible display layer is very thin, problems may occur in the device due to handling, etc. For this reason, there are cases where an adhesive film is bonded to this side to reinforce it (e.g., Patent Document 3).

[0005] Semiconductor substrates or flexible devices are subjected to repeated bending. If the bending characteristics of the adhesive film bonded to the substrate are poor, recovery after bending deteriorates, or in the worst case, the device may break due to repeated bending. Specifically, when an adhesive film is bonded to a bending section (e.g., a movable bending section of a folding member), if the film bends at an angle, compressive stress acts on the inner diameter side of the bend and tensile stress acts on the outer diameter side. Since stress deformation occurs in the bending section and its surroundings, there is a problem in that the semiconductor substrate or flexible device may break.

[0006] As a means of solving the above-mentioned problem, a method is conceived to alleviate the above-mentioned stress deformation by making the adhesive included in the adhesive film flexible.

[0007] Storage modulus G' is known as an indicator of the flexibility of an adhesive, and a technique for designing an adhesive such that the change rate of elasticity (G'(-20) / G'(40))×100, based on the storage modulus G'(-20) at -20°C and the storage modulus G'(40) at 40°C, is within a predetermined range (Patent Document 4), or a technique for designing an adhesive such that the change rate of 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, is within a predetermined range (Patent Document 5).

[0008] In the examples of Patent Document 4, an adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 2EHA / AA / 2HPA = 47.8 / 47.8 / 4 / 0.4 (by weight) and 0.9 parts by weight of a crosslinking agent (B) (Example 1), an adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 4HBA = 99 / 1 (by weight) and 0.15 parts by weight of a crosslinking agent (B) (Example 2), and an adhesive obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 2EHA / HEA = 47 / 48 / 5 (by weight) and 0.9 parts by weight of a crosslinking agent (B) (Example 3) are reported.

[0009] In the examples of Patent Document 5, adhesives obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 2EHA / 4HBA=54 / 45 / 1 (by weight) and 0.15 to 0.35 parts by weight of a crosslinking agent (B) (Example 1 to 10), adhesives obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 2EHA / 4HBA=52 / 45 / 3 (by weight) and 0.25 parts by weight of a crosslinking agent (B) (Example 11), and adhesives obtained from 100 parts by weight of a (meth)acrylic acid ester polymer (A) with a composition of BA / 2EHA / 4HBA=50 / 45 / 5 (by weight) and 0.25 parts by weight of a crosslinking agent (B) (Example 12) are reported.

[0010] However, making the adhesive flexible and reducing its elasticity generally increases the creep value. Consequently, adhesive tapes using conventional low-elasticity adhesives have a problem in that the fluidity of the adhesive increases due to heat, causing the adhesive to deform significantly—for example, during bump compression of an integrated circuit (IC). This leads to deformation of the semiconductor device substrate and subsequent connection failures. Prior art literature

[0011] Japanese Patent Publication No. 6366199 Japanese Patent Publication No. 5600039 Japanese Patent Publication No. 6376271 Japanese Patent Publication No. 6697359 Japanese Patent Publication No. 2020-139034 The problem to be solved

[0012] The objective of the present invention is to provide a reinforcing film comprising a substrate layer and an adhesive layer, wherein excellent low elasticity and excellent heat resistance are achieved simultaneously, and, for example, IC connection failures are difficult to occur. means of solving the problem

[0013] The reinforcing film according to an embodiment of the present invention is,

[0014] It is a reinforcing film comprising a substrate layer and an adhesive layer, and

[0015] The adhesive layer is composed of an acrylic adhesive, and

[0016] The surface elastic modulus of the adhesive layer at 25°C is 50 kPa to 1000 kPa, and

[0017] The MD direction heating shrinkage rate when the reinforcing film is heated at 180°C for 5 minutes is 1.0% or less.

[0018] In one embodiment, the reinforcing film according to the embodiment of the present invention has an adhesive strength of 5.0 N / 25 mm or more at 25°C on a polyimide film.

[0019] In one embodiment, the reinforcing film according to the embodiment of the present invention has a transmittance of 80% or more at a wavelength of 550 nm.

[0020] In one embodiment, the acrylic adhesive is a photocurable acrylic adhesive.

[0021] In one embodiment, the storage modulus G' of the adhesive layer at -20°C is 80 kPa to 300 kPa.

[0022] An optical member according to an embodiment of the present invention includes a reinforcing film according to an embodiment of the present invention.

[0023] An electronic member according to an embodiment of the present invention includes a reinforcing film according to an embodiment of the present invention. Effects of the invention

[0024] According to the present invention, a reinforcing film comprising a substrate layer and an adhesive layer can be provided, which has excellent low elasticity and excellent heat resistance, and, for example, is unlikely to have IC connection failures. Brief explanation of the drawing

[0025] FIG. 1 is a schematic cross-sectional view of one embodiment of the reinforcing film of the present invention. Specific details for implementing the invention

[0026] In this specification, if the expression “(meth)acryl” is used, it means “acrylate and / or methacrylate”; if the expression “(meth)acrylate” is used, it means “acrylate and / or methacrylate”; if the expression “(meth)allyl” is used, it means “allyl and / or metallyl”; and if the expression “(meth)acrolein” is used, it means “acrolein and / or methacrolein”. Additionally, if the expression “acid (salt)” is used in this specification, it means “acid and / or its salt”. Examples of salts include alkali metal salts and alkaline earth metal salts, and specifically, examples include sodium salts and potassium salts.

[0027] ≪≪1. Reinforcement Film≫≫

[0028] A reinforcing film according to an embodiment of the present invention comprises a substrate layer and an adhesive layer.

[0029] The substrate layer may be one layer or two or more layers. The substrate layer is preferably one layer in order to further express the effects of the present invention.

[0030] The adhesive layer may be one layer or two or more layers. The adhesive layer is preferably one layer in order to further express the effects of the present invention.

[0031] A reinforcing film according to an embodiment of the present invention may include a substrate layer and an adhesive layer, and may include any other suitable layer depending on the purpose, within a range that does not impair the effects of the present invention.

[0032] A reinforcing film according to an embodiment of the present invention includes a structure in which a substrate layer and an adhesive layer are directly laminated, in order to further express the effects of the present invention.

[0033] One embodiment of the reinforcing film of the present invention is, as shown in FIG. 1, a reinforcing film (100) comprises a substrate layer (10) and an adhesive layer (20).

[0034] The reinforcing film according to an embodiment of the present invention may be provided with any suitable release liner on the surface opposite to the adhesive layer's substrate layer for protection until use.

[0035] Examples of release liners include a release liner in which the surface of the substrate (liner substrate), such as paper or plastic film, is silicone-treated, or a release liner in which the surface of the substrate (liner substrate), such as paper or plastic film, is laminated with a polyolefin resin. Examples of plastic films used as liner substrates include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

[0036] 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.

[0037] The thickness of the reinforcing film according to an 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. If the thickness of the reinforcing film according to an embodiment of the present invention is within the above range, the effects of the present invention can be further expressed.

[0038] The reinforcing film according to an embodiment of the present invention has a MD direction heating shrinkage rate of 1.0% or less when heated at 180°C for 5 minutes, 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. The MD direction heating shrinkage rate is an indicator that can appropriately evaluate the heat resistance of the reinforcing film, and by adjusting this MD direction heating shrinkage rate to be very small as described above, the reinforcing film according to an embodiment of the present invention can exhibit excellent heat resistance. If the MD direction heating shrinkage rate exceeds the above range and increases, there is a concern that it may be difficult to exhibit excellent heat resistance. The method for measuring the MD direction heating shrinkage rate will be explained in detail later.

[0039] The reinforcing film according to an embodiment of the present invention has a surface elastic modulus of the adhesive layer 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 elastic modulus is an indicator that can appropriately evaluate the degree of low elasticity of the adhesive layer, and by adjusting this surface elastic modulus to within the specific range above, the reinforcing film according to an embodiment of the present invention can exhibit excellent low elasticity. If the surface elastic modulus deviates from the specific range above, there is a risk that it will be difficult to exhibit excellent low elasticity. The method for measuring the surface elastic modulus will be explained in detail later.

[0040] The reinforcing film according to an embodiment of the present invention has an adhesive strength at 25°C to a polyimide film that is preferably 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 at 25°C to the polyimide film is an indicator that can appropriately evaluate the adhesive strength as a reinforcing film for a substrate of a semiconductor device or a flexible device, etc. By adjusting this adhesive strength within the specific range above, the reinforcing film according to an embodiment of the present invention can be appropriately adhered to a substrate of a semiconductor device or a flexible device, etc. If the adhesive strength deviates from the specific range above, there is a risk that it will be difficult to appropriately adhere to a substrate of a semiconductor device or a flexible device, etc., as a reinforcing film. A method for measuring the adhesive strength at 25°C to the polyimide film will be explained in detail later.

[0041] The reinforcing film according to an embodiment of the present invention has an adhesive strength at -20°C to a polyimide film that is preferably 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 at -20°C to the polyimide film is an indicator that can appropriately evaluate the adhesive strength (especially the adhesive strength in a relatively low temperature range) as a reinforcing film for a substrate of a semiconductor device or a flexible device, etc. By adjusting this adhesive strength to within the specific range above, the reinforcing film according to an embodiment of the present invention can be appropriately adhered to a substrate of a semiconductor device or a flexible device, etc., even in a relatively low temperature range. If the adhesive strength deviates from the specific range above, there is a risk that it will be difficult to properly adhere to a substrate of a semiconductor device or a flexible device, etc., as a reinforcing film in a relatively low temperature range. The method for measuring the adhesive strength of the above polyimide film at -20℃ will be explained in detail later.

[0042] The reinforcing film according to an embodiment of the present invention has an adhesive strength at 180°C to a polyimide film that is preferably 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 at 180°C to the polyimide film is an indicator that can appropriately evaluate the adhesive strength (especially the adhesive strength in a relatively high temperature region) as a reinforcing film for a substrate of a semiconductor device or a flexible device, etc. By adjusting this adhesive strength to within the above specific range, the reinforcing film according to an embodiment of the present invention can be appropriately adhered to a substrate of a semiconductor device or a flexible device, etc., even in a relatively high temperature region. If the adhesive strength deviates from the above specific range, there is a risk that it will be difficult to properly adhere to a substrate of a semiconductor device or a flexible device, etc., as a reinforcing film in a relatively high temperature region. The method for measuring the adhesive strength of the above polyimide film at 180°C will be explained in detail later.

[0043] The reinforcing film according to an embodiment of the present invention has a transmittance at a wavelength of 550 nm that is preferably 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 indicator that can appropriately evaluate the inspection performance of the reinforcing film, and by adjusting this transmittance to a very high value as described above, the reinforcing film according to an embodiment of the present invention can exhibit excellent inspection performance. If the transmittance falls outside the above range and becomes smaller, there is a risk that it will be difficult to exhibit excellent inspection performance. The method for measuring the transmittance will be explained in detail later.

[0044] In the reinforcing film according to an embodiment of the present invention, the storage modulus G' of the adhesive layer at -20°C is preferably 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 indicator that can appropriately evaluate the stress relaxation properties of the adhesive layer (especially stress relaxation properties in a relatively low temperature range). By adjusting the storage modulus G' at -20°C to within the specific range mentioned above, the reinforcing film according to an embodiment of the present invention can exhibit excellent stress relaxation properties even in a relatively low temperature range, and furthermore, can exhibit very excellent low elasticity. If the storage modulus G' at -20°C deviates from the specific range mentioned above, there is a risk that it will be difficult to exhibit excellent stress relaxation properties. The method for measuring the storage modulus G' at -20℃ above will be explained in detail later.

[0045] In the reinforcing film according to an embodiment of the present invention, the storage modulus G' of the adhesive layer at 25°C is preferably 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 indicator that can appropriately evaluate the stress relaxation properties of the adhesive layer (particularly, stress relaxation properties in the room temperature range). By adjusting the storage modulus G' at 25°C to within the specific range mentioned above, the reinforcing film according to an embodiment of the present invention can exhibit excellent stress relaxation properties in the room temperature range and, furthermore, exhibit excellent low elasticity. If the storage modulus G' at 25°C deviates from the specific range mentioned above, there is a risk that it will be difficult to exhibit excellent stress relaxation properties. The method for measuring the storage modulus G' at 25°C will be explained in detail later.

[0046] In the reinforcing film according to an embodiment of the present invention, the storage modulus G' of the adhesive layer at 180°C is preferably 1 kPa to 100 kPa, more preferably 5 kPa to 50 kPa, even more preferably 8 kPa to 30 kPa, and particularly preferably 10 kPa to 20 kPa. The storage modulus G' at 180°C is an indicator that can appropriately evaluate the stress relaxation properties of the adhesive layer (particularly, stress relaxation properties in a high-temperature region). By adjusting the storage modulus G' at 180°C to within the specific range mentioned above, the reinforcing film according to an embodiment of the present invention can exhibit excellent stress relaxation properties in a high-temperature region and, furthermore, exhibit excellent low elasticity. If the storage modulus G' at 180°C deviates from the specific range mentioned above, there is a risk that it will be difficult to exhibit excellent stress relaxation properties. The method for measuring the storage modulus G' at 180°C will be explained in detail later.

[0047] ≪1-1. Recording Layer≫

[0048] 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. If the thickness of the substrate layer is within the above range, the effects of the present invention can be further expressed.

[0049] As for the material of the substrate layer, any suitable material may be adopted within a range that does not impair the effects of the present invention. Representative examples of such a substrate layer material include resin materials.

[0050] Examples of resin materials used as the material for the substrate layer include, for instance, acrylic resins such as polyimide (PI), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA), polycarbonate, triacetylcellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), fully aromatic polyamide (aramid), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorinated resin, and cyclic olefin polymer. The resin material used as the material for the substrate layer may be of only one type or two or more types.

[0051] The tensile modulus of the substrate layer, measured by a peel test at 200 mm / min at 25°C, is preferably 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 by a peel test at 200 mm / min at 25°C is an indicator that can appropriately evaluate the compatibility of heat resistance and flexibility of the substrate layer, and by adjusting the tensile modulus measured by a peel test at 200 mm / min at 25°C to within the specific range above, the reinforcing film according to an embodiment of the present invention can achieve excellent low elasticity and excellent heat resistance. If the tensile modulus obtained by the peel test at 200 mm / min at 25°C falls outside the aforementioned specific range, there is a concern that the reinforcing 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 obtained by the peel test at 200 mm / min at 25°C will be explained in detail later.

[0052] As for resin materials for a substrate layer that can adjust the tensile modulus of elasticity by a peel test at 200 mm / min at 25°C as described above to within the preferred range, examples include polyimide (PI) and annealed polyethylene terephthalate (annealed PET).

[0053] ≪1-2. Adhesive Layer≫

[0054] The adhesive layer consists of an acrylic adhesive. The acrylic adhesive is formed from an acrylic adhesive composition.

[0055] The thickness of the 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. If the thickness of the adhesive layer is within the above range, the effects of the present invention can be further expressed.

[0056] Acrylic adhesives can be defined as being formed from an acrylic adhesive composition. This is because, since acrylic adhesives are formed when an acrylic adhesive composition undergoes cross-linking reactions such as heating or ultraviolet irradiation, it is impossible to directly identify the acrylic adhesive by its structure, and furthermore, there exists a situation where such identification is generally impractical ("impossible / impractical situation"). Therefore, acrylic adhesives are validly identified as a "substance" by the definition of being "formed from an acrylic adhesive composition."

[0057] As a method for forming an acrylic adhesive, any suitable method may be employed within a range that does not impair the effects of the present invention. Examples of such a method for forming an acrylic adhesive include applying an acrylic adhesive composition onto any suitable substrate, performing heating or drying as necessary, and curing as necessary to form an acrylic adhesive in the form of a sheet on said substrate.

[0058] Any suitable means may be employed as a means of applying the acrylic adhesive composition, provided that the effects of the present invention are not impaired. Examples of such means of application 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.

[0059] Any suitable means may be employed for heating or drying the acrylic adhesive composition within a range that does not impair the effects of the present invention. Examples of such means for heating and drying include heating to 60°C to 180°C or performing an aging treatment at a temperature of room temperature.

[0060] Any suitable means may be employed for curing the acrylic adhesive composition within a range that does not impair the effects of the present invention. Examples of such means for curing include ultraviolet irradiation, laser irradiation, alpha ray irradiation, beta ray irradiation, gamma ray irradiation, X-ray irradiation, and electron ray irradiation.

[0061] Representative methods for forming an acrylic adhesive from an acrylic adhesive composition include a method of forming a photocurable acrylic adhesive by a photocuring reaction of a photocurable acrylic adhesive composition containing an acrylic polymer (typically an acrylic partial polymer) adjusted by polymerization using a photopolymerization initiator (typically partial polymerization), and a method of forming a thermosetting acrylic adhesive by a crosslinking reaction of a thermosetting acrylic adhesive composition containing an acrylic polymer adjusted by solution polymerization using a thermal polymerization initiator. That is, as acrylic adhesives, examples include a photocurable acrylic adhesive formed by the photocuring reaction of a photocurable acrylic adhesive composition comprising an acrylic polymer (typically an acrylic partial polymer) (P1) adjusted by polymerization using a photopolymerization initiator (typically partial polymerization), and a thermosetting acrylic adhesive formed by the crosslinking reaction of a thermosetting acrylic adhesive composition comprising an acrylic polymer (P2) adjusted by solution polymerization using a thermal polymerization initiator.

[0062] <1-2-1. Acrylic Polymer (P1)>

[0063] One embodiment of the acrylic polymer is an acrylic polymer (P1) prepared by polymerization using a photopolymerization initiator (typically, partial polymerization). As for the method of polymerization using a photopolymerization initiator, any suitable method may be adopted within a range that does not impair the effects of the present invention, such as, for example, conventionally known methods. In polymerization using a photopolymerization initiator, typically, light such as UV is irradiated.

[0064] The acrylic polymer (P1) is preferably an acrylic partial polymer (sometimes referred to as an acrylic prepolymer). Unlike a complete polymer of monomer components (preferably a polymer with a polymerization conversion rate of more than 95 weight%), the acrylic partial polymer is a partial polymer obtained by preferably reducing the polymerization conversion rate of monomer components to 95 weight% or less.

[0065] 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, and more preferably 5% by weight or more.

[0066] The acrylic polymer (P1) is obtained by polymerizing the monomer component (M1). The monomer component (M1) referred to herein does not include the crosslinking agent described below that may be included in the acrylic adhesive composition. When obtaining the acrylic polymer (P1) by polymerization, any suitable additive may be used in addition to the monomer component (M1) and the photopolymerization initiator, provided that it does not impair the effects of the present invention.

[0067] The acrylic polymer (P1) can be defined as being obtained by polymerizing the monomer component (M1) in this manner. This is because the acrylic polymer (P1) is formed when the monomer component (M1) undergoes a polymerization reaction, and since there is a situation ("impossibility / unrealistic situation") where it is impossible and generally impractical to directly identify the acrylic polymer (P1) by its structure, the acrylic polymer (P1) is validly identified as a "substance" by the definition of being "obtained by polymerizing the monomer component (M1)."

[0068] The acrylic polymer (P1) has a Tg that is preferably -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 express the effects of the present invention. By adjusting the Tg of the acrylic polymer (P1) to within the specific ranges above, the reinforcing film according to the embodiment of the present invention can further achieve excellent low elasticity.

[0069] The Tg of an acrylic polymer (P1) refers to a value obtained from Fox's formula based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P1) and the weight fraction (copolymerization ratio based on weight) of the corresponding monomer. Fox's formula is a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer formed by homopolymerizing each of the monomers constituting the copolymer, as described below.

[0070] 1 / Tg=Σ(Wi / Tgi)

[0071] In the above Fox formula, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio based on weight), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K). As for the Tg of the homopolymer, the value described in known materials shall be adopted.

[0072] As the Tg of the homopolymer, for example, specifically the following values ​​can be used.

[0073] n-Butyl Acrylate (BA): -55℃

[0074] Lauryl Acrylate (LA): -23℃

[0075] 2-Ethylhexyl Acrylate (2EHA): -70℃

[0076] 2-Hydroxyethyl acrylate (2HEA): -15℃

[0077] 4-Hydroxybutyl acrylate (2HBA): -40℃

[0078] N-Vinyl-2-Pyrrolidone (NVP): 80℃

[0079] For homopolymer Tg values ​​other than those exemplified above, values ​​listed in the “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989) may be used. If multiple values ​​are listed in the “Polymer Handbook,” the conventional value shall be adopted. For monomers not listed in the “Polymer Handbook,” the catalog value from the monomer manufacturer shall be adopted. For the Tg of a homopolymer of a monomer not listed in the “Polymer Handbook” and for which a catalog value from the monomer manufacturer is not provided, the value obtained by the measurement method described in Japanese Patent Publication No. 2007-51271 shall be used.

[0080] The monomer component (M1) preferably comprises an alkyl (meth)acrylate (a1) and a polar group-containing monomer (b1). The alkyl (meth)acrylate (a1) may be of only one type or two or more types. The polar group-containing monomer (b1) may be of only one type or two or more types.

[0081] [1-2-1-1. Alkyl (meth)acrylate (a1)]

[0082] The alkyl group of the ester portion of the alkyl (meth)acrylate (a1) (hereinafter referred to as the “alkyl group of the ester portion”) does not include alkyl groups containing hydroxyl groups or alkyl groups containing polar groups other than hydroxyl groups. Therefore, the alkyl (meth)acrylate (a1) is clearly distinguished from the polar group-containing monomer (b1).

[0083] The content ratio of alkyl (meth)acrylate (a1) in the monomer component (M1) is preferably 50% to 99% by weight, more preferably 70% to 99% by weight, even more preferably 80% to 99% by weight, particularly preferably 82% to 99% by weight, and most preferably 85% to 99% by weight, in order to further express the effects of the present invention.

[0084] The alkyl group of the ester portion 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 order to further express the effects of the present invention.

[0085] The alkyl group of the ester portion is preferably a chain-like alkyl group in that it can further express the effects of the present invention. Here, "chain-like" means including straight chains and branched chains.

[0086] As for the alkyl (meth)acrylate (a1) in which the alkyl group of the ester portion is a chain alkyl group having 1 to 20 carbon atoms, examples 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, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, and isodecyl (meth)acrylate. Examples include 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.

[0087] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a1) that can be included in the monomer component (M1) has a glass transition temperature Tg of its homopolymer (homopolymer) that is preferably -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 included in the monomer component (M1) can affect the adhesive properties or low elasticity of the acrylic polymer (P1). By employing an alkyl (meth)acrylate (a1) that can be included in the monomer component (M1), wherein the glass transition temperature Tg of its homopolymer (homopolymer) is within the above range, the adhesiveness or low elasticity of the acrylic polymer (P1) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0088] Here, as the glass transition temperature Tg of a homopolymer of an alkyl (meth)acrylate (a1) that may be included in the monomer component (M1), a value described in known materials may be adopted, for example, a value described in the “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989). Furthermore, if multiple values ​​are described in the “Polymer Handbook,” a conventional value is adopted. For alkyl (meth)acrylates not described in the “Polymer Handbook,” a catalog value from a monomer manufacturer is adopted. For a homopolymer of an alkyl (meth)acrylate not described in the “Polymer Handbook” and for which a catalog value from a monomer manufacturer is not provided, the value obtained by the measurement method described in Japanese Patent Publication No. 2007-51271 is used.

[0089] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a1) that may be included in the monomer component (M1) preferably includes an alkyl (meth)acrylate (a1-1) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C). By including the alkyl (meth)acrylate (M1) as an alkyl (meth)acrylate (a1-1), the effects of the present invention can be further expressed.

[0090] Examples of alkyl (meth)acrylates (a1-1) include lauryl acrylate (LA) (glass transition temperature Tg of its homopolymer = -23°C).

[0091] The content ratio of alkyl (meth)acrylate (a1-1) in the total amount of alkyl (meth)acrylate (a1) that can be included 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 express the effects of the present invention.

[0092] The content ratio of alkyl (meth)acrylate (a1-1) in the total amount of monomer component (M1) is preferably 10% to 80% by weight, more preferably 15% to 70% by weight, even more preferably 20% to 60% by weight, particularly preferably 25% to 50% by weight, and most preferably 30% to 45% by weight, in order to further express the effects of the present invention.

[0093] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a1) that may be included in the monomer component (M1) preferably includes an alkyl (meth)acrylate (a1-2) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C). By including the alkyl (meth)acrylate (M1) as an alkyl (meth)acrylate (a1-2), the effects of the present invention can be further expressed.

[0094] As for alkyl (meth)acrylates (a1-2), for example, 2-ethylhexyl acrylate (2EHA) (glass transition temperature Tg of its homopolymer = -70°C).

[0095] The content ratio of alkyl (meth)acrylate (a1-2) in the total amount of alkyl (meth)acrylate (a1) that can be included in the monomer component (M1) is preferably 20% to 90% by weight, more preferably 30% to 80% by weight, even more preferably 40% to 75% by weight, particularly preferably 45% to 70% by weight, and most preferably 50% to 65% by weight, in order to further express the effects of the present invention.

[0096] The content ratio of alkyl (meth)acrylate (a1-2) in the total amount of monomer component (M1) is preferably 10% to 80% by weight, more preferably 20% to 75% by weight, even more preferably 30% to 70% by weight, particularly preferably 35% to 65% by weight, and most preferably 40% to 60% by weight, in order to further express the effects of the present invention.

[0097] The monomer component (M1) may include an alkyl (meth)acrylate (a1-3) in which the glass transition temperature Tg of its homopolymer (homopolymer) is in the range of greater than -60°C and less than -40°C, to the extent that it does not impair the effects of the present invention.

[0098] As for alkyl (meth)acrylates (a1-3), for example, n-butyl acrylate (BA) (glass transition temperature Tg of its homopolymer = -55°C).

[0099] The content ratio of alkyl (meth)acrylate (a1-3) in the total amount of alkyl (meth)acrylate (a1) that can be included 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 express the effects of the present invention.

[0100] The content ratio 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 express the effects of the present invention.

[0101] [1-2-1-2. Polar group-containing monomer (b1)]

[0102] The content ratio 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 express the effects of the present invention.

[0103] In order to further express the effects of the present invention, the polar group-containing monomer (b1) preferably comprises at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer having a polar group other than a hydroxyl group (b1-2), and more preferably comprises both the hydroxyl group-containing monomer (b1-1) and the monomer having a polar group other than a hydroxyl group (b1-2).

[0104] The hydroxyl group-containing monomer (b1-1) may be one type or two or more types.

[0105] Examples of hydroxyl group-containing monomers (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.

[0106] In order to further express the effects of the present invention, the hydroxyl group-containing monomer (b1-1) has a glass transition temperature Tg of its homopolymer (homopolymer) that is preferably -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 (homopolymer) of the hydroxyl group-containing monomer (b1-1) can affect the adhesive properties or low elasticity of the acrylic polymer (P1). By employing a hydroxyl group-containing monomer (b1-1) that can be included in the monomer component (M1), wherein the glass transition temperature Tg of its homopolymer (homopolymer) is within the above range, the adhesive properties or low elasticity of the acrylic polymer (P1) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0107] Regarding the glass transition temperature Tg of a homopolymer of a hydroxyl group-containing monomer (b1-1), the description of the glass transition temperature Tg of a homopolymer of an alkyl (meth)acrylate (a1) that may be included in the monomer component (M1) in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be used.

[0108] In order to further express 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 portion of the hydroxyalkyl group is a straight-chain alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature Tg=-15°C of its homopolymer), 4-hydroxybutyl acrylate (4HBA) (glass transition temperature Tg=-40°C of its homopolymer), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature Tg=-40°C of its homopolymer).

[0109] The content ratio of the hydroxyl group-containing monomer (b1-1) in the polar group-containing monomer (b1) is preferably 20% to 100% by weight, more preferably 25% to 95% by weight, even more preferably 30% to 90% by weight, particularly preferably 35% to 85% by weight, and most preferably 40% to 80% by weight, in order to further express the effects of the present invention.

[0110] The content ratio of the hydroxyl group-containing monomer (b1-1) in the monomer component (M1) is preferably 0.05% to 30% by weight, more preferably 0.1% to 20% by weight, even more preferably 1% to 15% by weight, particularly preferably 2% to 10% by weight, and most preferably 4% to 9% by weight, in order to further express the effects of the present invention.

[0111] Monomers (b1-2) having polar groups other than hydroxyl groups may be of only one type or two or more types.

[0112] Examples of monomers (b1-2) having polar groups other than hydroxyl groups include, for instance, 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.

[0113] Examples of carboxyl 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.

[0114] Nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include, for example, nitrogen-containing vinyl monomers such as methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, N-vinylcaprolactam; and cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile.

[0115] In order to further express the effects of the present invention, the monomer (b1-2) having a polar group other than a hydroxyl group has a glass transition temperature Tg of its homopolymer (homopolymer) that 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 (homopolymer) of the monomer (b1-2) having a polar group other than a hydroxyl group can affect the adhesive properties or low elasticity of the acrylic polymer (P1). By employing a monomer having a polar group other than a hydroxyl group as a monomer (b1-2) having a polar group other than a hydroxyl group that can be included in the monomer component (M1), the glass transition temperature Tg of its homopolymer (homopolymer) is within the above range, the adhesive properties or low elasticity of the acrylic polymer (P1) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0116] As for the monomer (b1-2) having a polar group other than a hydroxyl group, preferably, the monomer having a polar group other than a hydroxyl group has a glass transition temperature Tg of its homopolymer (homopolymer) of 50°C to 100°C, in order to further express the effects of the present invention. The glass transition temperature Tg of the homopolymer (homopolymer) of this monomer is preferably 60°C to 95°C, and more preferably 70°C to 90°C.

[0117] Regarding the glass transition temperature Tg of a homopolymer (homopolymer) of a monomer (b1-2) having a polar group other than a hydroxyl group, the description of the glass transition temperature Tg of a homopolymer (homopolymer) of an alkyl (meth)acrylate (a1) that can be included in the monomer component (M1) in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be used.

[0118] In order to further enhance the effects of the present invention, N-vinyl-2-pyrrolidone (glass transition temperature Tg=80℃ of its homopolymer) is preferably used as a monomer (b1-2) having a polar group other than a hydroxyl group.

[0119] The content ratio 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 express the effects of the present invention.

[0120] The content ratio 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 express the effects of the present invention.

[0121] In order to further express the effects of the present invention, the monomer component (M1) preferably comprises at least one selected from the group consisting of an alkyl (meth)acrylate (a1), a hydroxyl group-containing monomer (b1-1), and a monomer having a polar group other than a hydroxyl group (b1-2), more preferably comprises an alkyl (meth)acrylate (a1), a hydroxyl group-containing monomer (b1-1), and a monomer having a polar group other than a hydroxyl group (b1-2), and even more preferably comprises an alkyl (meth)acrylate (a1-1) having a glass transition temperature Tg of its homopolymer (homopolymer) within the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), and a homopolymer having a glass transition temperature Tg of its homopolymer (homopolymer) within the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C). It includes an alkyl (meth)acrylate (a1-2) within the range of -65°C, a hydroxyl group-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0122] In order to further express the effects of the present invention, the content ratio of the total amount of the monomer component (M1), the alkyl (meth)acrylate (a1-1) having a glass transition temperature Tg of its homopolymer 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) having 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), the hydroxyl group-containing monomer (b1-1), and the monomer having a polar group other than a hydroxyl group (b1-2), is preferably 60% to 100% by weight, more preferably 70% to 100% by weight, and even more preferably 80% to 100% by weight, particularly Preferably 90% to 100% by weight, and most preferably 95% to 100% by weight.

[0123] In order to further enhance the effects of the present invention, the monomer component (M1) specifically, preferably, comprises lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, and N-vinyl-2-pyrrolidone.

[0124] [1-2-1-3. Other monomers (c1)]

[0125] The monomer component (M1) may include other monomers (c1) that do not correspond to either the alkyl (meth)acrylate (a1) or the polar group-containing monomer (b1). The other monomers (c1) may be used for purposes such as adjusting the glass transition temperature (Tg) of the acrylic polymer (P1) or adjusting adhesive performance. The other monomers may be one type or two or more types.

[0126] The content ratio of other monomers (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.

[0127] [1-2-1-4. Photopolymerization Initiator]

[0128] As for the photopolymerization initiator, any suitable photopolymerization initiator can be appropriately selected depending on the type of polymerization method. The photopolymerization initiator may be one type or two or more types.

[0129] Examples of photopolymerization initiators include, for instance, 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, acylphosphine oxide-based photopolymerization initiators, etc.

[0130] Examples of benzoin ether-based photopolymerization initiators include, specifically, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one (commercially available examples include, for instance, the trade name "OMNIRAD651", manufactured by IGM Resins BV), anisole methyl ether, etc.

[0131] Examples of acetophenone-based photopolymerization initiators include, specifically, 1-hydroxycyclohexylphenylketone (commercially available, for example, trade name "OMNIRAD 184", manufactured by IGM Resins BV), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (commercially available, for example, trade name "OMNIRAD 2959", manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenyl-propan-1-one, methoxyacetophenone, etc.

[0132] Examples of α-ketol photopolymerization initiators include, specifically, 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropan-1-one, etc.

[0133] Examples of aromatic sulfonyl chloride-based photopolymerization initiators include, specifically, 2-naphthalenesulfonyl chloride.

[0134] Specific examples of photoactive oxime-based photopolymerization initiators include, for instance, 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0135] Specifically, benzoin-based photopolymerization initiators include, for example, benzoin.

[0136] Specifically, benzyl-based photopolymerization initiators include, for example, benzyl.

[0137] Examples of benzophenone-based photopolymerization initiators include, specifically, benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexylphenylketone, etc.

[0138] Examples of ketal-based photopolymerization initiators include, specifically, benzyldimethylketal.

[0139] Examples of thioxantone-based photopolymerization initiators include, specifically, thioxantone, 2-chlorothioxantone, 2-methylthioxantone, 2,4-dimethylthioxantone, isopropylthioxantone, 2,4-dichlorothioxantone, 2,4-diethylthioxantone, isopropylthioxantone, 2,4-diisopropylthioxantone, dodecylthioxantone, etc.

[0140] Acylphosphine-based photopolymerization initiators, specifically, for example, 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-methylpropane-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropane-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-t-butylphosphine oxide, bis(2,6-dimethoxybenzoyl)cyclohexylphosphine oxide, bis(2,6-dimethoxybenzoyl)octylphosphine oxide, Bis(2-methoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, Bis(2-methoxybenzoyl)(1-methylpropane-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(1-methylpropane-1-yl)phosphine oxide, Bis(2,6-dibutoxybenzoyl)(2-methylpropane-1-yl)phosphine oxide, Bis(2,4-dimethoxybenzoyl)(2-methylpropane-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,Examples include 4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)isobutylphosphine oxide, 2,6-dimethoxybenzoyl-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.

[0141] The amount of photopolymerization initiator used can be set to any appropriate amount within a range that does not impair the effects of the present invention. The amount of 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, with respect to further expressing the effects of the present invention, with respect to 100 parts by weight of monomer component (M1).

[0142] <1-2-2. Acrylic Polymer (P2)>

[0143] One embodiment of the acrylic polymer is an acrylic polymer (P2) prepared by solution polymerization using a thermal polymerization initiator. As for the method of polymerization using a thermal polymerization initiator, any suitable method may be adopted within a range that does not impair the effects of the present invention, such as, for example, a conventionally known method.

[0144] The acrylic polymer (P2) is obtained by polymerizing the monomer component (M2). The monomer component (M2) referred to herein does not include the crosslinking agent described below that may be included in the acrylic adhesive composition. When obtaining the acrylic polymer (P2) by polymerization, any suitable additive may be used in addition to the monomer component (M2) and the thermal polymerization initiator, provided that it does not impair the effects of the present invention.

[0145] The acrylic polymer (P2) can be defined as being obtained by polymerizing the monomer component (M2) in this manner. This is because the acrylic polymer (P2) is formed when the monomer component (M2) undergoes a polymerization reaction, and since there is a situation ("impossibility / unrealistic situation") where it is impossible and generally impractical to directly identify the acrylic polymer (P2) by its structure, the acrylic polymer (P2) is validly identified as a "substance" by the definition of being "obtained by polymerizing the monomer component (M2)."

[0146] The acrylic polymer (P2) has a Tg that is preferably -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 express the effects of the present invention. By adjusting the Tg of the acrylic polymer (P2) to within the specific ranges above, the reinforcing film according to the embodiment of the present invention can further achieve excellent low elasticity.

[0147] The Tg of an acrylic polymer (P2) refers to a value obtained from Fox's formula based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P2) and the weight fraction (weight-based copolymerization ratio) of the corresponding monomer. For Fox's formula and the Tg of various homopolymers, the explanation in <1-2-1. Acrylic Polymer (P1)> may be referenced.

[0148] The monomer component (M2) preferably comprises an alkyl (meth)acrylate (a2) and a polar group-containing monomer (b2). The alkyl (meth)acrylate (a2) may be of only one type or two or more types. The polar group-containing monomer (b2) may be of only one type or two or more types.

[0149] [1-2-2-1. Alkyl (meth)acrylate (a2)]

[0150] The alkyl group of the ester portion of the alkyl (meth)acrylate (a2) (hereinafter referred to as the “alkyl group of the ester portion”) does not include alkyl groups containing hydroxyl groups or alkyl groups containing polar groups other than hydroxyl groups. Therefore, the alkyl (meth)acrylate (a2) is clearly distinguished from the polar group-containing monomer (b2).

[0151] The content ratio of alkyl (meth)acrylate (a2) in the monomer component (M2) is preferably 70% to 99.9% by weight, more preferably 80% to 99.5% by weight, even more preferably 90% to 99.2% by weight, even more preferably 93% to 99.2% by weight, particularly preferably 95% to 99% by weight, and most preferably 97% to 99% by weight.

[0152] The alkyl group of the ester portion 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 order to further express the effects of the present invention.

[0153] The alkyl group of the ester portion is preferably a chain-like alkyl group in that it can further express the effects of the present invention. Here, "chain-like" means including straight chains and branched chains.

[0154] For the alkyl (meth)acrylate (a2) in which the alkyl group of the ester portion is a chain alkyl group having 1 to 20 carbon atoms, the description of the alkyl (meth)acrylate (a1) in which the alkyl group of the ester portion is a chain alkyl group having 1 to 20 carbon atoms in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be referenced.

[0155] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a2) that can be included in the monomer component (M2) has a glass transition temperature Tg of its homopolymer (homopolymer) that is preferably -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 included in the monomer component (M2) can affect the adhesive properties or low elasticity of the acrylic polymer (P2). By employing an alkyl (meth)acrylate (a2) that can be included in the monomer component (M2), wherein the glass transition temperature Tg of its homopolymer is within the above range, the adhesiveness or low elasticity of the acrylic polymer (P2) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0156] Here, regarding the glass transition temperature Tg of the homopolymer (homopolymer) of the alkyl (meth)acrylate (a2) that may be included in the monomer component (M2), the explanation regarding the glass transition temperature Tg of the homopolymer (homopolymer) of the alkyl (meth)acrylate (a1) that may be included in the monomer component (M1) in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be referenced.

[0157] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a2) that may be included in the monomer component (M2) preferably includes an alkyl (meth)acrylate (a2-1) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C). By including the alkyl (meth)acrylate (M2) as an alkyl (meth)acrylate (a2-1), the effects of the present invention can be further expressed.

[0158] Examples of alkyl (meth)acrylates (a2-1) include lauryl acrylate (LA) (glass transition temperature Tg of its homopolymer = -23°C).

[0159] The content ratio of alkyl (meth)acrylate (a2-1) in the total amount of alkyl (meth)acrylate (a2) that can be included 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 express the effects of the present invention.

[0160] The content ratio of alkyl (meth)acrylate (a2-1) in the total amount of 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 express the effects of the present invention.

[0161] In order to further express the effects of the present invention, the alkyl (meth)acrylate (a2) that may be included in the monomer component (M2) preferably includes an alkyl (meth)acrylate (a2-2) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C). By including the alkyl (meth)acrylate (M2) as an alkyl (meth)acrylate (a2-2), the effects of the present invention can be further expressed.

[0162] Examples of alkyl (meth)acrylates (a2-2) include 2-ethylhexyl acrylate (2EHA) (glass transition temperature Tg of its homopolymer = -70°C).

[0163] The content ratio of alkyl (meth)acrylate (a2-2) in the total amount of alkyl (meth)acrylate (a2) that can be included in the monomer component (M2) is preferably 40% to 95% by weight, more preferably 50% to 90% by weight, even more preferably 55% to 85% by weight, particularly preferably 60% to 80% by weight, and most preferably 65% ​​to 75% by weight, in order to further express the effects of the present invention.

[0164] The content ratio of alkyl (meth)acrylate (a2-2) in the total amount of monomer component (M2) is preferably 40% to 95% by weight, more preferably 50% to 90% by weight, even more preferably 55% to 85% by weight, particularly preferably 60% to 80% by weight, and most preferably 65% ​​to 75% by weight, in order to further express the effects of the present invention.

[0165] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a2) that can be included in the monomer component (M2) preferably includes an alkyl (meth)acrylate (a2-3) in which the glass transition temperature Tg of its homopolymer (homopolymer) is in the range of greater than -60°C and less than -40°C.

[0166] As for alkyl (meth)acrylates (a2-3), for example, n-butyl acrylate (BA) (glass transition temperature Tg of its homopolymer = -55°C).

[0167] The content ratio of alkyl (meth)acrylate (a2-3) in the total amount of alkyl (meth)acrylate (a2) that can be included 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 express the effects of the present invention.

[0168] The content ratio of alkyl (meth)acrylate (a2-3) in the total amount of 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 express the effects of the present invention.

[0169] [1-2-2-2. Polar group-containing monomer (b2)]

[0170] The content ratio 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, even 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 express the effects of the present invention.

[0171] In order to further express the effects of the present invention, the polar group-containing monomer (b2) preferably comprises at least one selected from the group consisting of a hydroxyl group-containing monomer (b2-1) and a monomer having a polar group other than a hydroxyl group (b2-2), and more preferably comprises both the hydroxyl group-containing monomer (b2-1) and the monomer having a polar group other than a hydroxyl group (b2-2).

[0172] The hydroxyl group-containing monomer (b2-1) may be one type or two or more types.

[0173] For the hydroxyl group-containing monomer (b2-1), the description of the hydroxyl group-containing monomer (b1-1) in [1-2-1-2. Polar group-containing monomer (b1)] may be referenced.

[0174] In order to further express the effects of the present invention, the hydroxyl group-containing monomer (b2-1) has a glass transition temperature Tg of its homopolymer (homopolymer) that is preferably -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 (homopolymer) of the hydroxyl group-containing monomer (b2-1) can affect the adhesive properties or low elasticity of the acrylic polymer (P2). By employing a hydroxyl group-containing monomer (b2-1) that can be included in the monomer component (M2) and whose homopolymer (homopolymer) has a glass transition temperature Tg within the above range, the adhesive properties or low elasticity of the acrylic polymer (P2) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0175] Regarding the glass transition temperature Tg of a homopolymer of a hydroxyl group-containing monomer (b2-1), the description of the glass transition temperature Tg of a homopolymer of an alkyl (meth)acrylate (a1) that may be included in the monomer component (M1) in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be used.

[0176] In order to further express 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 portion of the hydroxyalkyl group is a straight-chain alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature Tg=-15°C of its homopolymer), 4-hydroxybutyl acrylate (4HBA) (glass transition temperature Tg=-40°C of its homopolymer), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature Tg=-40°C of its homopolymer).

[0177] The content ratio 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 express the effects of the present invention.

[0178] The content ratio 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 express the effects of the present invention.

[0179] Monomers (b2-2) having polar groups other than hydroxyl groups may be of only one type or two or more types.

[0180] For the monomer (b2-2) having a polar group other than a hydroxyl group, the description of the monomer (b1-2) having a polar group other than a hydroxyl group in [1-2-1-2. Monomer containing a polar group (b1)] may be referenced.

[0181] In order to further express the effects of the present invention, the monomer (b2-2) having a polar group other than a hydroxyl group has a glass transition temperature Tg of its homopolymer (homopolymer) that 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 (homopolymer) of the monomer (b2-2) having a polar group other than a hydroxyl group can affect the adhesive properties or low elasticity of the acrylic polymer (P2). By employing a monomer having a polar group other than a hydroxyl group as a monomer (b2-2) having a polar group other than a hydroxyl group that can be included in the monomer component (M2), the glass transition temperature Tg of its homopolymer (homopolymer) is within the above range, the adhesive properties or low elasticity of the acrylic polymer (P2) can be appropriately adjusted, and the effects of the present invention can be further expressed.

[0182] As for the monomer (b2-2) having a polar group other than a hydroxyl group, preferably, the monomer having a polar group other than a hydroxyl group has a glass transition temperature Tg of its homopolymer (homopolymer) of 50°C to 100°C, in order to further express the effects of the present invention. The glass transition temperature Tg of the homopolymer (homopolymer) of this monomer is preferably 60°C to 95°C, and more preferably 70°C to 90°C.

[0183] Regarding the glass transition temperature Tg of a homopolymer (homopolymer) of a monomer (b2-2) having a polar group other than a hydroxyl group, the description of the glass transition temperature Tg of a homopolymer (homopolymer) of an alkyl (meth)acrylate (a1) that can be included in the monomer component (M1) in [1-2-1-1. Alkyl (meth)acrylate (a1)] may be used.

[0184] In order to further enhance the effects of the present invention, N-vinyl-2-pyrrolidone (glass transition temperature Tg=80℃ of its homopolymer) is preferably used as a monomer (b2-2) having a polar group other than a hydroxyl group.

[0185] The content ratio of the monomer (b2-2) having a polar group other than a hydroxyl group in the monomer (b2) containing a polar group 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 express the effects of the present invention.

[0186] The content ratio 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 express the effects of the present invention.

[0187] In order to further express the effects of the present invention, the monomer component (M2) preferably comprises at least one selected from the group consisting of 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, more preferably comprises 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 even more preferably comprises an alkyl (meth)acrylate (a2-1) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), and the glass transition temperature Tg of its homopolymer (homopolymer) is in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to It includes an alkyl (meth)acrylate (a2-2) within the range of -65℃, an alkyl (meth)acrylate (a2-3) in which the glass transition temperature Tg of its homopolymer (homopolymer) is within the range of greater than -60℃ and less than -40℃, a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group.

[0188] In order to further express the effects of the present invention, the content ratio of the total amount of the monomer component (M2) comprising an alkyl (meth)acrylate (a2-1) having a glass transition temperature Tg of its homopolymer (homopolymer) 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) having a glass transition temperature Tg of its homopolymer (homopolymer) in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), an alkyl (meth)acrylate (a2-3) having a glass transition temperature Tg of its homopolymer (homopolymer) in the range of greater than -60°C and less than -40°C, a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group is preferably It is 60% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 80% to 100% by weight, particularly preferably 90% to 100% by weight, and most preferably 95% to 100% by weight.

[0189] In order to further enhance the effects of the present invention, the monomer component (M2) specifically, preferably, comprises lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, n-butyl acrylate, and N-vinyl-2-pyrrolidone.

[0190] [1-2-2-3. Other monomers (c2)]

[0191] The monomer component (M2) may include other monomers (c2) that do not correspond to either the alkyl (meth)acrylate (a2) or the polar group-containing monomer (b2). The other monomers (c2) may be used for purposes such as adjusting the glass transition temperature (Tg) of the acrylic polymer (P2) or adjusting adhesive performance. The other monomers may be of only one type or two or more types.

[0192] The content ratio of the other monomer (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.

[0193] [1-2-2-4. Thermal Polymerization Initiator]

[0194] As a thermal polymerization initiator, any suitable thermal polymerization initiator may be appropriately selected depending on the type of polymerization method. The thermal polymerization initiator may be one type or two or more types.

[0195] As thermal polymerization initiators, for example, 2,2'-azobis-isobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobis-isovaleronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), Azo-based initiators such as 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, manufactured by Wako Junyaku Kogyo Co., Ltd.); Persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroylperoxide, di-n-octanoylperoxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoylperoxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butylhydroperoxide, peroxide-based initiators such as hydrogen peroxide; Examples include redox initiators combining a peroxide and a reducing agent, such as a combination of persulfate and sodium bisulfite, or a combination of peroxide and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0196] The amount of thermal polymerization initiator used can be set to any appropriate amount within a range that does not impair the effects of the present invention. The amount of 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, with respect to further expressing the effects of the present invention, with respect to 100 parts by weight of monomer component (M2).

[0197] <1-2-3. Photocurable acrylic adhesive composition and photocurable acrylic adhesive>

[0198] One embodiment of the acrylic adhesive is a photocurable acrylic adhesive, and the photocurable acrylic adhesive is formed by a photocurable acrylic adhesive composition containing an acrylic polymer (P1), typically.

[0199] A photocurable acrylic adhesive is formed from a photocurable acrylic adhesive composition by any suitable method. Representative examples of such a formation method include applying a photocurable acrylic adhesive composition onto any suitable substrate, then placing a separate suitable substrate on the surface of the adhesive layer formed by application, and curing it by irradiating with ultraviolet light. Examples of substrates include the release liner described above. As for the method of applying the photocurable acrylic adhesive composition, any suitable application method may be used within a range that 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.

[0200] When forming a photocurable acrylic adhesive, heating may be performed as necessary. Additionally, aging may be performed for the purpose of controlling component migration within the formed photocurable acrylic adhesive, promoting cross-linking reactions, and alleviating deformation that may exist within the photocurable acrylic adhesive.

[0201] [1-2-3-1. Crosslinking agent (L1)]

[0202] The photocurable acrylic adhesive composition preferably includes a crosslinking agent (L1). The crosslinking agent (L1) may be one type or two or more types.

[0203] The content of the crosslinking agent (L1) in the photocurable acrylic adhesive composition can be set to any appropriate amount within a range that does not impair the effects of the present invention. The content of the crosslinking agent (L1) in the photocurable acrylic 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, with respect to further expressing the effects of the present invention, with respect to 100 parts by weight of the acrylic polymer (P1).

[0204] As for the crosslinking agent (L1), any suitable crosslinking agent may be employed within a range that does not impair the effects of the present invention. Preferably, such a crosslinking agent (L1) is a polyfunctional (meth)acrylate.

[0205] As for the polyfunctional (meth)acrylate, any suitable polyfunctional (meth)acrylate may be used within a range that does not impair the effects of the present invention. The polyfunctional (meth)acrylate may be one type or two or more types. As such polyfunctional (meth)acrylates, specifically, ester compounds of (meth)acrylic acid with polyhydric alcohols such as (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-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylates; vinyl (meth)acrylates; Examples include divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl di(meth)acrylate; and hexyl di(meth)acrylate.

[0206] [1-2-3-2. Acrylic Oligomers]

[0207] The photocurable acrylic adhesive composition may include an acrylic oligomer. The acrylic oligomer may be of only one type or two or more types.

[0208] The content of the acrylic oligomer in the photocurable acrylic adhesive composition can be set to any appropriate amount within a range that does not impair the effects of the present invention. The content of the acrylic oligomer in the photocurable acrylic 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, with respect to 100 parts by weight of the acrylic polymer (P1), in order to further express the effects of the present invention.

[0209] The weight average molecular weight of the acrylic oligomer is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, even more preferably 1,500 to 10,000, and particularly preferably 2,000 to 8,000. By including the acrylic oligomer in the photocurable acrylic adhesive composition, the effects of the present invention can be further expressed.

[0210] In addition, the weight-average molecular weight (Mw) can be obtained by converting it to polystyrene using the GPC method. For example, it can be measured under the following conditions using the high-speed GPC device "HPLC-8120GPC" manufactured by Toso Co., Ltd.

[0211] Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000

[0212] Solvent: Tetrahydrofuran

[0213] Flow rate: 0.6 ml / min

[0214] The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C to 300°C, more preferably 30°C to 300°C, and more preferably 40°C to 300°C.

[0215] The Tg of an acrylic oligomer refers to a value obtained from Fox's formula based on the Tg of the homopolymer of each monomer constituting the acrylic oligomer and the weight fraction of the corresponding monomer (copolymerization ratio based on weight). For Fox's formula and the Tg of various homopolymers, the explanation in <1-2-1. Acrylic Polymer (P1)> may be referenced.

[0216] As for the acrylic oligomer, an acrylic oligomer obtained from a monomer composition having a (meth)acrylic acid ester having a cyclic structure within the molecule as an essential component is preferred, and an acrylic oligomer obtained from a monomer composition having a (meth)acrylic acid ester having a cyclic structure within the molecule and a (meth)acrylic acid alkyl ester having a straight-chain or branched-chain alkyl group as essential components is more preferred.

[0217] (Met)acrylic acid esters having a cyclic structure within the molecule may be of only one type or two or more types.

[0218] A (meth)acrylate alkyl ester having a straight-chain or branched-chain alkyl group may be one type or two or more types.

[0219] In (meth)acrylic acid esters having a cyclic structure within the molecule, the cyclic structure may be either an aromatic ring or a non-aromatic ring.

[0220] Examples of aromatic rings include aromatic carbon rings (e.g., single-ring carbon rings such as the benzene ring, or condensed carbon rings such as the naphthalene ring), and various aromatic complex rings.

[0221] Examples of non-aromatic rings include, for instance, non-aromatic aliphatic rings (non-aromatic alicyclic rings) (e.g., cycloalkane rings such as cyclophenane, cyclohexane, cycloheptane, and cyclooctane; cycloalkene rings such as cyclohexene), non-aromatic crosslinking rings (e.g., bicyclic hydrocarbon rings in pinan, pinene, bornan, norbornan, norbornene; three or more aliphatic hydrocarbon rings (crosslinked hydrocarbon rings) in adamantane), and non-aromatic heterocyclic rings (e.g., epoxy rings, oxolan rings, oxetane rings). Examples of aliphatic hydrocarbon rings with three or more rings (cross-linked hydrocarbon rings with three or more rings) include dicyclofentanyl groups, dicyclofentenyl groups, adamantyl groups, tricyclofentanyl groups, and tricyclofentenyl groups.

[0222] As (meth)acrylic acid esters having a cyclic structure within the molecule, specifically, for example, (meth)acrylic acid cycloalkyl esters such as (meth)acrylic acid cyclopentyl, (meth)acrylic acid cyclohexyl, (meth)acrylic acid cycloheptyl, (meth)acrylic acid cyclooctyl; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as (meth)acrylic acid isobornyl; (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings such as dicyclofentanyl (meth)acrylate, dicyclofentanyloxyethyl (meth)acrylate, tricyclofentanyl (meth)acrylate, 1-adamanthyl (meth)acrylate, 2-methyl-2-adamanthyl (meth)acrylate, and 2-ethyl-2-adamanthyl (meth)acrylate; Examples include (meth)acrylic acid esters having an aromatic ring, such as (meth)acrylic acid aryl esters of (meth)acrylic acid phenyl, (meth)acrylic acid aryloxyalkyl esters of (meth)acrylic acid phenoxyethyl, (meth)acrylic acid arylalkyl esters of (meth)acrylic acid benzyl, (meth)acrylic acid esters of (meth)acrylic acid arylalkyl esters.

[0223] As for (meth)acrylic acid esters having a cyclic structure within the molecule, non-aromatic ring-containing (meth)acrylic acid esters are preferably used to further express the effects of the present invention, more preferably cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclofentanyl acrylate (DCPA), and dicyclofentanyl methacrylate (DCPMA), and even more preferably dicyclofentanyl acrylate (DCPA) and dicyclofentanyl methacrylate (DCPMA).

[0224] The content ratio of (meth)acrylic acid ester having a cyclic structure within the molecule among the total monomers that can be used to form an acrylic oligomer is preferably 10 to 90 parts by weight and more preferably 20 to 80 parts by weight with respect to 100 parts by weight of the total monomers, in order to further express the effects of the present invention.

[0225] As alkyl esters of (meth)acrylate having a straight-chain or branched-chain alkyl group, examples include (meth)acrylate 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 isooctyl, (meth)acrylate nonyl, (meth)acrylate isononyl, (meth)acrylate decyl, (meth)acrylate isodecyl, (meth)acrylate undecyl. Examples include (meth)acrylate alkyl esters having 1 to 20 carbon atoms in an alkyl group, such as (meth)acrylate dodecyl, (meth)acrylate tridecyl, (meth)acrylate tetradecyl, (meth)acrylate pentadecyl, (meth)acrylate hexadecyl, (meth)acrylate heptadecyl, (meth)acrylate octadecyl, (meth)acrylate nonadecyl, and (meth)acrylate eicosyl. Among these, methyl methacrylate (MMA) is preferred in that it can further express the effects of the present invention.

[0226] The content ratio of (meth)acrylic acid alkyl ester having a straight-chain or branched-chain alkyl group among the total monomers that can be used to form an 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, with respect to the fact that it can further express the effects of the present invention.

[0227] The total monomer (monomer composition) that can be used to form an acrylic oligomer may include, in addition to (meth)acrylic acid esters having a cyclic structure within the molecule and (meth)acrylic acid alkyl esters having a straight-chain or branched-chain alkyl group, other monomers capable of copolymerizing with these monomers (copolymerizable monomers). The content of other monomers (copolymerizable monomers) in the total monomer (monomer composition) that can be used to form an 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, based on 100 parts by weight of the total monomer.

[0228] Other such monomers (copolymerizable monomers) include, for example, (meth)acrylic acid alkoxyalkyl esters (e.g., (meth)acrylic acid 2-methoxyethyl, (meth)acrylic acid 2-ethoxyethyl, (meth)acrylic acid methoxytriethylene glycol, (meth)acrylic acid 3-methoxypropyl, (meth)acrylic acid 3-ethoxypropyl, (meth)acrylic acid 4-methoxybutyl, (meth)acrylic acid 4-ethoxybutyl, etc.), carboxyl group-containing monomers (e.g., acid anhydride-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, etc.), and hydroxyl group-containing monomers (e.g., (meth)acrylic acid 2-hydroxyethyl, (meth)acrylic acid 3-hydroxypropyl, (meth)acrylate hydroxyalkyls such as 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate; 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 vinylsulfonate, etc.), phosphate group-containing Examples include monomers (e.g., 2-hydroxyethylacryloyl phosphate, etc.), monomers containing isocyanate groups (e.g., 2-methacryloyloxyethylisocyanate, etc.), monomers containing imide groups (e.g., cyclohexylmaleimide, isopropylmaleimide, etc.).

[0229] The total monomer (monomer composition) that can be used to form an acrylic oligomer comprises, particularly preferably, (1) at least one monomer selected from dicyclofentanyl acrylate, dicyclofentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and (2) methyl methacrylate. In this case, with respect to 100 parts by weight of the total monomer (monomer composition) that can be used to form an acrylic oligomer, the content of the monomer of (1) is preferably 30 to 70 parts by weight, and the content of the monomer of (2) is preferably 30 to 70 parts by weight.

[0230] Acrylic oligomers can be prepared by any suitable polymerization within a range that does not impair the effects of the present invention. Examples of such polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy irradiation (active energy polymerization method). Among these, preferably, bulk polymerization and solution polymerization methods are used, and more preferably, solution polymerization methods are used.

[0231] Examples of solvents that can be used in 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. The solvent may be of only one type or two or more types.

[0232] In polymerization, any suitable polymerization initiator (e.g., a thermal polymerization initiator or a photopolymerization initiator, etc.) may be employed within a range that does not impair the effects of the present invention. The polymerization initiator may be one type or two or more types. In addition, when performing solution polymerization, it is preferable to use an oil-soluble polymerization initiator.

[0233] As a thermal polymerization initiator, any suitable thermal polymerization initiator may be employed within a range that 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 description in [1-2-2-4. Thermal Polymerization Initiators] may be referenced.

[0234] The content of the thermal polymerization initiator is preferably 0.1 to 15 parts by weight per 100 parts by weight of the total monomer (monomer composition) that can be used to form an acrylic oligomer, for example.

[0235] As a photopolymerization initiator, any suitable photopolymerization initiator may be employed within a range that 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 description in [1-2-1-4. Photopolymerization Initiators] may be referenced.

[0236] The content of the photopolymerization initiator is preferably 0.001 to 0.5 parts by weight per 100 parts by weight of the total monomer (monomer composition) that can be used to form an acrylic oligomer, for example.

[0237] When polymerizing acrylic oligomers, 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 chain transfer agents 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 ester of ethylene glycol, thioglycolic acid ester of neopentyl glycol, thioglycolic acid ester of pentaerythritol, α-methylstyrene dimer, etc. Among these, α-thioglycerol and methyl thioglycolate are preferred, and α-thioglycerol is particularly preferred, from the perspective of suppressing whitening of the double-sided adhesive tape of the present invention. The chain transfer agent may be one type or two or more types.

[0238] The content of the chain transfer agent is, for example, 0.1 to 20 parts by weight per 100 parts by weight of the total monomer (monomer composition) that can be used to form an acrylic oligomer, preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight.

[0239] [1-2-3-3. Other Components]

[0240] The photocurable acrylic adhesive composition may include any other suitable components to the extent that it does not impair the effects of the present invention. Examples of such other components include tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, film materials, softeners, anti-aging agents, 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.

[0241] <1-2-4. Thermosetting Acrylic Adhesive Composition and Thermosetting Acrylic Adhesive>

[0242] One embodiment of the acrylic adhesive is a thermosetting acrylic adhesive, and the thermosetting acrylic adhesive is formed by a crosslinking reaction of a thermosetting acrylic adhesive composition containing an acrylic polymer (P2), typically.

[0243] A thermosetting acrylic adhesive is formed from a thermosetting acrylic adhesive composition by any suitable method. Representative examples of such a formation method include applying a thermosetting acrylic adhesive composition onto any suitable substrate, performing heating and drying as needed, and curing as needed to form a sheet of thermosetting acrylic adhesive on the said substrate. Any application method may be adopted 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.

[0244] For heating and drying the thermosetting acrylic adhesive composition, any suitable means may be employed within a range that does not impair the effects of the present invention. Examples of such means for heating and drying include heating to a temperature of approximately 60°C to 180°C. For curing the thermosetting acrylic adhesive composition, any suitable means may be employed within a range that does not impair the effects of the present invention. Examples of such means for curing include ultraviolet irradiation, laser irradiation, alpha ray irradiation, beta ray irradiation, gamma ray irradiation, X-ray irradiation, and electron ray irradiation.

[0245] When forming a thermosetting acrylic adhesive, aging may be performed as needed for the purpose of controlling component migration within the formed thermosetting acrylic adhesive, promoting crosslinking reactions, and alleviating deformation that may exist within the photocurable acrylic adhesive.

[0246] [1-2-4-1. Crosslinking agent (L2)]

[0247] The thermosetting acrylic adhesive composition preferably includes a crosslinking agent (L2). The crosslinking agent (L2) may be one type or two or more types.

[0248] By using a crosslinking agent (L2), appropriate cohesive force can be imparted to the thermosetting acrylic adhesive. The crosslinking agent (L2) may be included in the thermosetting acrylic adhesive in a form after the crosslinking reaction, a form before the crosslinking reaction, a form that has undergone partial crosslinking, or an intermediate or composite form thereof. Typically, the crosslinking agent (L2) is included in the thermosetting acrylic adhesive in a form after the crosslinking reaction.

[0249] In order to further express the effects of the present invention, the content ratio of the crosslinking agent (L2) in the thermosetting acrylic 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, even more preferably 0.01 to 1 part by weight, even more preferably 0.01 to 0.7 parts by weight, even 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.

[0250] Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, and peroxides. In order to further express the effects of the present invention, it is preferably an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a peroxide, and more preferably an isocyanate-based crosslinking agent or a peroxide.

[0251] As an isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including isocyanate regenerating polar groups in which the isocyanate groups are temporarily protected by blocking agents or merizing, etc.) in one molecule may be used. Examples of isocyanate-based crosslinking agents include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0252] As isocyanate-based crosslinking agents, for example, 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; Isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adducts (e.g., manufactured by Dosoh Co., Ltd., trade name Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adducts (e.g., manufactured by Dosoh Co., Ltd., trade name: Coronate HL), and isocyanurate forms of hexamethylene diisocyanate (e.g., manufactured by Dosoh Co., Ltd., trade name: Coronate HX); Examples include trimethylolpropane adducts of xylylene diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: Takenate D140N), trimethylolpropane adducts of hexamethylene diisocyanate (e.g., manufactured by Mitsui Chemicals, trade name: Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols; and polyisocyanates multifunctionalized by isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferably used because they can achieve a balanced combination of deformability and cohesiveness.

[0253] As an epoxy-based crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. As epoxy-based crosslinking agents, for example, 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, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, Examples include triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Examples of commercially available epoxy crosslinking agents include the trade names "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Corporation.

[0254] As peroxides, for example, dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butylhydroperoxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexine-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-butylperoxyneodecanoate, Examples include 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-butylperoxypivalate, and t-hexyl peroxypivalate. Examples of commercially available peroxides include the "Niper BMT" series and "Niper BW" series manufactured by Nippon Yushi Co., Ltd.

[0255] [1-2-4-2. Acrylic Oligomers]

[0256] The thermosetting acrylic adhesive composition may include an acrylic oligomer. The acrylic oligomer may be of only one type or two or more types. For the acrylic oligomer, the description in [1-2-3-2. Acrylic Oligomer] may be referenced.

[0257] [1-2-4-3. Other Components]

[0258] The thermosetting acrylic adhesive composition may include any other suitable components to the extent that it does not impair the effects of the present invention. Examples of such other components include tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, thin films, softeners, anti-aging agents, 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.

[0259] ≪≪2. Uses of Reinforcement Film≫≫

[0260] The reinforcing film according to an embodiment of the present invention can be used for any suitable purpose. The surface protection film of the present invention is preferably used, for example, for reinforcing optical members or electronic members. Examples of optical members include LCDs, touch panels using LCDs, color filters used in LCDs, polarizers, etc.

[0261] That is, the optical member according to an embodiment of the present invention has the reinforcing film of the present invention attached thereto. In addition, the electronic member according to an embodiment of the present invention has the reinforcing film of the present invention attached thereto.

[0262] The above optical or electronic member may be a flexible device such as a bendable device having a movable bend, a foldable device, or a rollable device.

[0263] [Example]

[0264] The present invention will be explained in more detail below with reference to examples and comparative examples. However, the present invention is not limited thereto. Furthermore, in the following description, "parts" and "%" are based on weight unless otherwise specified.

[0265] The abbreviations and details of the raw materials, etc. used in the following manufacturing examples, examples, and comparative examples are as follows.

[0266] 2EHA: 2-ethylhexyl acrylic acid (glass transition temperature Tg of its homopolymer = -70℃)

[0267] LA: Lauryl acrylate (glass transition temperature Tg of its homopolymer Tg=-23℃)

[0268] BA: n-butyl acrylate (glass transition temperature Tg of its homopolymer Tg=-55℃)

[0269] 4HBA: 4-hydroxybutyl acrylate (glass transition temperature Tg of its homopolymer Tg = -32℃)

[0270] NVP: N-vinyl-2-pyrrolidone (glass transition temperature Tg of its homopolymer = 80°C)

[0271] MMA: Methyl methacrylate

[0272] HEA: 2-hydroxyethyl acrylic acid

[0273] AIBN: 2,2'-Azobisisobutyronitrile

[0274] Omnirad184: Photopolymerization initiator (manufacturing of IGM resins)

[0275] A-HD-N: 1,6-Hexanediol Diacrylate (HDDA) (Manufactured by Shin-Nakamura Kagaku Kogyo Co., Ltd.)

[0276] BPO: Product name "Naiper BW" (Peroxide, manufactured by Nichiyu Co., Ltd.)

[0277] <Surface elastic modulus of the adhesive layer at 25°C>

[0278] The release liner was peeled off from the obtained reinforcing film and obtained using an AFM by the following method.

[0279] 1) A sample of approximately 5 mm × 10 mm was cut out and fixed to a designated sample holder.

[0280] 2) The spring constant used to calculate the surface elastic modulus adopted the value stated by the manufacturer.

[0281] 3) The sensitivity coefficient was determined using a silicon wafer.

[0282] 4) Before measurement, static electricity was removed, and force curve mapping measurements were performed at 16 × 16 points in an area of ​​50 µm (a square of 50 µm x 50 µm) using an AFM.

[0283] 5) The obtained force curve was converted into a load-displacement curve using the spring constant and sensitivity coefficient of 2) and 3) above.

[0284] 6) Using the load-displacement curve of 5) above, the surface elastic modulus was calculated using the JKR 2-point method.

[0285] 7) A histogram of 256 data points was created from the obtained surface elastic modulus mapping, and a Gaussian fit was performed.

[0286] 8) The Gaussian-fit mode was used as the value of the surface elasticity modulus and read.

[0287] Device: Manufactured by Oxford Instruments, Asylum Research MFP-3D-SA

[0288] Measurement Mode: AFM Force Curve Mapping (16×16 points), Speed ​​2Hz

[0289] Cantilever: Manufactured by NANOSENSORS, SD-R150-FM (Manufactured by Si, equivalent spring constant 2.8 N / m)

[0290] Measurement range: 50㎛

[0291] Measurement atmosphere: Atmospheric pressure

[0292] Measured temperature: 25℃

[0293] <MD 방향 가열 수축률>

[0294] The heat shrinkage rate of the reinforcing film in the MD direction (long side direction) was calculated as follows.

[0295] Specifically, a reinforcing film with a release liner attached was cut to a size of 100 mm in width and 100 mm in length to serve as a test specimen, and the length in the MD direction (mm) was measured using a Quick Vision image measuring device equipped with a non-contact displacement sensor (manufactured by Mitutoyo Corporation). Afterward, the release liner was peeled off, the test specimen was placed with the adhesive layer facing upward, and heat treatment (180°C, 5 minutes) was performed. After cooling at room temperature for 1 hour, the length in the MD direction (mm) was measured again using a Quick Vision image measuring device equipped with a non-contact displacement sensor (manufactured by Mitutoyo Corporation), and the heat shrinkage rate in the MD direction was calculated by substituting the measured value into the following formula.

[0296] MD direction heating shrinkage rate (%) = [(Length before heating (mm) - Length after heating (mm)) / Length before heating (mm)] × 100

[0297] <Adhesion strength of polyimide film at 25℃>

[0298] A polyimide film with a thickness of 25 μm (manufactured by Ube Kosan, “U-Fillers S”) was attached to a glass plate via a double-sided adhesive tape (manufactured by Nitto Denko, “No. 531”) to obtain a polyimide film substrate for measurement.

[0299] A release liner was peeled off from the surface of a reinforcing film cut to a width of 25 mm × a length of 100 mm, and bonded to a polyimide film substrate for measurement using a hand roller to produce a sample for measuring adhesive strength.

[0300] After bonding and leaving at 25°C for 1 day, the end of the substrate layer of the reinforcing film was held and supported by a chuck, and a 180° peel test of the reinforcing film was performed at a tensile speed of 300 mm / min under a 25°C environment to measure the peel strength, and the obtained peel strength was taken as the adhesion strength at 25°C for the polyimide film.

[0301] <Adhesion strength of polyimide film at -20℃>

[0302] A polyimide film with a thickness of 25 μm (manufactured by Ube Kosan, “U-Fillers S”) was attached to a glass plate via a double-sided adhesive tape (manufactured by Nitto Denko, “No. 531”) to obtain a polyimide film substrate for measurement.

[0303] A release liner was peeled off from the surface of a reinforcing film cut to a width of 25 mm × a length of 100 mm, and bonded to a polyimide film substrate for measurement using a hand roller to produce a sample for measuring adhesive strength.

[0304] After bonding and leaving at 25°C for 1 day, the end of the substrate layer of the reinforcing film was held and supported by a chuck, and a 180° peel test of the reinforcing film was performed at a tensile speed of 300 mm / min under a -20°C environment to measure the peel strength, and the obtained peel strength was used as the adhesion strength at -20°C for the polyimide film.

[0305] <Adhesion strength of polyimide film at 180°C>

[0306] A polyimide film with a thickness of 25 μm (manufactured by Ube Kosan, “U-Fillers S”) was attached to a glass plate via a double-sided adhesive tape (manufactured by Nitto Denko, “No. 531”) to obtain a polyimide film substrate for measurement.

[0307] A release liner was peeled off from the surface of a reinforcing film cut to a width of 25 mm × a length of 100 mm, and bonded to a polyimide film substrate for measurement using a hand roller to produce a sample for measuring adhesive strength.

[0308] After bonding and leaving at 25°C for 1 day, the end of the substrate layer of the reinforcing film was held and supported by a chuck, and a 180° peel test of the reinforcing film was performed at a tensile speed of 300 mm / min under an environment of 180°C to measure the peel strength, and the obtained peel strength was taken as the adhesive strength at 180°C for the polyimide film.

[0309] <Transmittance at wavelength 550nm>

[0310] The transmittance of the fabricated reinforcing film at 550 nm was measured using a spectrophotometer (manufactured by Hitachi Seisakusho Co., Ltd., model: U-4100).

[0311] <Storage modulus G' of the adhesive layer at -20℃>

[0312] [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)]

[0313] An adhesive composition was applied to the peel-treated surface of a 75㎛ thick polyester film (product name "Diafoil MRF75", manufactured by Mitsubishi Chemical Co., Ltd.) with one side peeled with silicone, such that the thickness after drying was 25㎛ using a fountain roll, and then cured and dried under conditions of a drying temperature of 130℃ and a drying time of 1 minute. In this way, an adhesive layer was produced on a substrate. Subsequently, a 75㎛ thick polyester film (product name "Diafoil MRF75", manufactured by Mitsubishi Chemical Co., Ltd.) with one side peeled with silicone was coated onto the surface of the adhesive layer with the peel-treated surface of the polyester film facing the adhesive layer, and aging was performed at 50℃ for 1 day to produce an adhesive sheet with a thickness of 25㎛ as a sample.

[0314] [Sample Preparation Method 2 (Examples 1, 2, 6, 9 to 10, 14, Comparative Examples 1, 2, 6)]

[0315] A 75㎛ thick polyester film (product name "Diafoil MRF75," manufactured by Mitsubishi Chemical Co., Ltd.), with one side peeled off with silicone, was used as a substrate (also serving as a medium-release film), and an adhesive composition was applied to the substrate to a thickness of 25㎛ to form a coating layer. A 75㎛ thick polyester film (product name "Diafoil MRF75," manufactured by Mitsubishi Chemical Co., Ltd.), with one side peeled off with silicone, was bonded onto this coating layer as a cover sheet (also serving as a light-release film). To this laminate, the irradiation intensity at the irradiation surface directly below the lamp from the cover sheet side is 5mW / cm² 2 Photocuring was performed by irradiating ultraviolet light with a black light positioned to such an extent, and an adhesive sheet with a thickness of 25 μm was produced as a sample.

[0316] 〔measurement method〕

[0317] It was obtained by the following method using a dynamic viscoelasticity measuring device (manufactured by Rheometrics, ARES).

[0318] Only the adhesive layer was extracted from the adhesive sheet obtained as a sample, laminated to a thickness of approximately 1 mm, punched to φ8 mm, and produced as a cylindrical pellet to serve as a measurement sample. The obtained measurement sample was fixed to a jig of a φ8 mm parallel plate, and the storage modulus G' was calculated using the dynamic viscoelasticity measuring device. The measurement conditions are as follows.

[0319] Measurement: Shear mode

[0320] Temperature range: -70℃ to 200℃

[0321] Heating rate: 5℃ / min

[0322] Frequency: 1Hz

[0323] <Tensile modulus of the substrate layer>

[0324] Both ends of a substrate layer cut to a width of 10 mm × a length of 100 mm were held and supported by a chuck, and a peel test was performed at a tensile speed of 200 mm / min under a 25°C environment, and the tensile modulus was measured (in accordance with JIS K7161).

[0325] [Preparation Example 1]: Preparation of acrylic polymer A (UV polymerization)

[0326] As monomer components for forming a prepolymer, 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 as a photopolymerization initiator were mixed, and polymerization was carried out by irradiating with ultraviolet light to obtain a solution of acrylic polymer A (prepolymer) (polymerization rate: about 10%).

[0327] [Preparation Example 2]: Preparation of acrylic polymer B (solution polymerization)

[0328] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 70 parts by weight of 2-ethylhexyl acrylate (2EHA), 20 parts by weight of butyl acrylate (BA), 1 part by weight of 4-hydroxybutyl acrylic acid (4HBA), 8 parts by weight of lauryl acrylate (LA), and 0.6 parts by weight of N-vinyl-2-pyrrolidone (NVP) were added as monomers, 0.2 parts by weight of azobisisobutyronitrile (AIBN) as a thermal polymerization initiator, and 120 parts by weight of ethyl acetate as a solvent were added, and nitrogen purging was performed for about 1 hour while flowing nitrogen gas and stirring. Afterward, the mixture was 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.

[0329] [Preparation Example 3]: Preparation of acrylic polymer C (UV polymerization)

[0330] As monomer components for forming a prepolymer, 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 as a photopolymerization initiator were mixed, and polymerization was carried out by irradiating with ultraviolet light to obtain a solution of acrylic polymer C (prepolymer) (polymerization rate: about 10%).

[0331] [Preparation Example 4]: Preparation of acrylic polymer D (solution polymerization)

[0332] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 65 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinyl-2-pyrrolidone (NVP), 12 parts by weight of 2-hydroxyethyl acrylic acid (HEA), and 8 parts by weight of methyl methacrylate (MMA) were added as monomers, 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 flowed, and nitrogen purging was performed for about 1 hour while stirring. Afterward, the mixture was 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.

[0333] [Preparation Example 5]: Preparation of acrylic polymer E (solution polymerization)

[0334] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 99 parts by weight of butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate (HEA) were added 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 flowed, and nitrogen purging was performed for about 1 hour while stirring. Afterward, the mixture was 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.

[0335] [Preparation Example 6]: Preparation of acrylic polymer F (solution polymerization)

[0336] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 95 parts by weight of butyl acrylate (BA) and 5 parts by weight of acrylic acid (AA) were added as monomers, 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 flowed, and nitrogen purging was performed for about 1 hour while stirring. Afterward, the mixture was 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.

[0337] [Preparation Example 7]: Preparation of Acrylic Oligomer A

[0338] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 62 parts by weight of dicyclofentanyl methacrylate (DCPMA) and 38 parts by weight of methyl methacrylate (MMA) were added 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 flowed, and nitrogen purging was performed for about 1 hour while stirring. Afterward, the mixture was heated to 70°C and reacted for 2 hours, followed by reacting at 80°C for 4 hours, and then reacting at 90°C for 1 hour to obtain a solution of acrylic oligomer A with a weight average molecular weight of 4000.

[0339] [Preparation Example 8]: Preparation of Acrylic Oligomer B

[0340] In a reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet, 96 parts by weight of cyclohexyl methacrylate (CHMA) and 4 parts by weight of acrylic acid (AA) were added 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 flowed, and nitrogen purging was performed for about 1 hour while stirring. Afterward, the mixture was heated to 70°C and reacted for 3 hours, and further reacted at 75°C for 2 hours to obtain a solution of acrylic oligomer B with a weight-average molecular weight of 4000.

[0341] [Example 1]

[0342] (Production of annealed polyethylene terephthalate film)

[0343] A polyethylene terephthalate film with a thickness of 50 μm that has not undergone surface treatment (manufactured by Mitsubishi Chemical, product name “T100C50”) was heat-treated at 200°C for 5 minutes to produce an annealed polyethylene terephthalate film (hereinafter referred to as an annealed PET film).

[0344] (Preparation of adhesive composition (1))

[0345] 100 parts by weight of acrylic polymer A, 0.08 parts by weight of 1,6-hexanediol diacrylate (HDDA) (product name "A-HD-N", manufactured by Shin-Nakamura Kagaku Kogyo Co., Ltd.) as a post-added component, and 6 parts by weight of acrylic oligomer A were added, and then uniformly mixed to prepare an adhesive composition (1).

[0346] (Production of adhesive sheets)

[0347] A polyethylene terephthalate (PET) film with a thickness of 75 μm (manufactured by Mitsubishi Chemical, product name "Diafoil MRF75") having a silicone-based release layer on its surface was used as a substrate (and also a medium-release film), and the adhesive composition (1) described above was applied to the substrate to a thickness of 15 μm to form a coating layer. A PET film with a thickness of 75 μm (manufactured by Mitsubishi Chemical, product name "Diafoil MRE75"), having one side treated with silicone peeling, was bonded onto this coating layer as a cover sheet (and also a light-release film). In the obtained laminate, the irradiation intensity at the irradiation surface directly below the lamp from the cover sheet side was 5 mW / cm² 2 Photocuring was performed by irradiating ultraviolet rays with a black light positioned to such an extent, and an adhesive sheet with a thickness of 15㎛ was produced.

[0348] (Production of reinforcing film (1))

[0349] The release film of the obtained adhesive sheet was peeled off and bonded onto an annealed PET film as a substrate to produce a reinforcing film (1).

[0350] Various results are shown in Table 1.

[0351] [Example 2]

[0352] A reinforcing film (2) was produced in the same manner as in Example 1, except that the thickness of the adhesive composition after drying was changed to 25 μm.

[0353] Various results are shown in Table 1.

[0354] [Example 3]

[0355] (Production of annealed polyethylene terephthalate film)

[0356] An annealed PET film was prepared in the same manner as in Example 1.

[0357] (Preparation of adhesive composition (3))

[0358] An adhesive composition (3) was prepared by adding 100 parts by weight of acrylic polymer B, 6 parts by weight of acrylic oligomer A, and 0.38 parts by weight of "Naiper BW" (BPO) manufactured by Nichiyu as a crosslinking agent.

[0359] (Production of reinforcing film (3))

[0360] An adhesive composition (3) was applied to an annealed PET using a fountain roll so that the thickness after drying was 15 μm. After drying at 130°C for 1 minute to remove the solvent, a release liner (a polyethylene terephthalate film with a thickness of 25 μm and a silicone release liner on the surface) was bonded to the coated surface. Then, an aging treatment was performed for 4 days in an atmosphere of 25°C, and crosslinking was carried out to produce a reinforcing film (3).

[0361] Various results are shown in Table 1.

[0362] [Example 4]

[0363] A reinforcing film (4) was produced in the same manner as in Example 3, except that the thickness of the adhesive composition after drying was changed to 25 μm.

[0364] Various results are shown in Table 1.

[0365] [Example 5]

[0366] (Production of annealed polyethylene terephthalate film)

[0367] An annealed PET film was prepared in the same manner as in Example 1.

[0368] (Preparation of adhesive composition (5))

[0369] An adhesive composition (5) was prepared by adding 100 parts by weight of acrylic polymer B, 1.5 parts by weight of acrylic oligomer B, and 0.28 parts by weight of "Naiper BW" (BPO) manufactured by Nichiyu as a crosslinking agent.

[0370] (Production of reinforcing film (5))

[0371] A reinforcing film (5) was produced in the same manner as in Example 3, except that the adhesive composition (3) was changed to the adhesive composition (5).

[0372] Various results are shown in Table 1.

[0373] [Example 6]

[0374] (Production of annealed polyethylene terephthalate film)

[0375] An annealed PET film was prepared in the same manner as in Example 1.

[0376] (Preparation of adhesive composition (6))

[0377] 100 parts by weight of acrylic polymer C, 0.08 parts by weight of 1,6-hexanediol diacrylate (HDDA) (product name "A-HD-N", manufactured by Shin-Nakamura Kagaku Kogyo Co., Ltd.) as a post-added component, and 2 parts by weight of acrylic oligomer A were added, and then uniformly mixed to prepare an adhesive composition (6).

[0378] (Production of adhesive sheets)

[0379] An adhesive sheet with a thickness of 25 μm was produced 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.

[0380] (Production of reinforcing film (6))

[0381] The release film of the obtained adhesive sheet was peeled off and bonded onto an annealed PET film to produce a reinforcing film (6).

[0382] Various results are shown in Table 1.

[0383] [Example 7]

[0384] (Production of annealed polyethylene terephthalate film)

[0385] An annealed PET film was prepared in the same manner as in Example 1.

[0386] (Preparation of adhesive composition (7))

[0387] An adhesive composition (7) was prepared by adding 100 parts by weight of acrylic polymer E, 1.5 parts by weight of acrylic oligomer A, 0.3 parts by weight of Nichiyu’s “Naiper BW” (BPO) as a crosslinking agent, and 0.1 parts by weight of a trifunctional isocyanate compound (Mitsui Kagaku’s “Takenate D-110N”).

[0388] (Production of reinforcing film (7))

[0389] An adhesive composition (7) was applied to an annealed PET using a fountain roll so that the thickness after drying was 25 μm. After drying at 130°C for 1 minute to remove the solvent, a release liner (a polyethylene terephthalate film with a thickness of 25 μm and a silicone release liner on the surface) was bonded to the coated surface. Then, an aging treatment was performed for 4 days in an atmosphere of 25°C, and crosslinking was carried out to produce a reinforcing film (7).

[0390] Various results are shown in Table 1.

[0391] [Example 8]

[0392] (Production of annealed polyethylene terephthalate film)

[0393] An annealed PET film was prepared in the same manner as in Example 1.

[0394] (Preparation of adhesive composition (8))

[0395] An adhesive composition (8) was prepared by adding 100 parts by weight of an acrylic polymer F, 25 parts by weight of an 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.

[0396] (Production of reinforcing film (8))

[0397] An adhesive composition (8) was applied to an annealed PET using a fountain roll so that the thickness after drying was 15 μm. After drying at 130°C for 1 minute to remove the solvent, a release liner (a polyethylene terephthalate film with a thickness of 25 μm and a silicone release liner on the surface) was bonded to the coated surface. Then, an aging treatment was performed for 4 days in an atmosphere of 25°C, and crosslinking was carried out to produce a reinforcing film (8).

[0398] Various results are shown in Table 1.

[0399] [Examples 9 to 16]

[0400] Reinforcement films (9) to (16) were produced in the same manner as Examples 1 to 8, except that a polyimide (PI) film with a thickness of 50 μm (manufactured by Toray DuPont, trade name “Kapton 200H”) was used as the substrate.

[0401] Various results are shown in Table 1.

[0402] [Comparative Examples 1 to 6]

[0403] Reinforcement films (C1) to (C6) were produced in the same manner as in Examples 1 to 6, except that a polyethylene terephthalate film with a thickness of 50 μm that has not undergone surface treatment (manufactured by Mitsubishi Chemical, product name “T100C50”) was used as the substrate.

[0404] Various results are shown in Table 1.

[0405] [Comparative Example 7]

[0406] (Preparation of adhesive composition (C7))

[0407] An adhesive composition (C7) was prepared by adding 0.25 parts by weight of a trifunctional isocyanate compound (manufactured by Mitsui Kagaku, trade name "Takenate D-110N") as a crosslinking agent to 100 parts by weight of an acrylic polymer D.

[0408] (Production of adhesive sheets)

[0409] A 15 μm thick adhesive sheet was produced in the same manner as in Example 1, except that adhesive composition (C7) was used instead of adhesive composition (1).

[0410] (Production of reinforcing film (C7))

[0411] The release film of the obtained adhesive sheet was peeled off and bonded onto a 50 μm thick polyethylene terephthalate film (manufactured by Mitsubishi Chemical, product name “T100C50”) that has no surface treatment as a substrate, thereby producing a reinforcing film (C7).

[0412] Various results are shown in Table 1.

[0413] [Comparative Example 8]

[0414] A reinforcing film (C8) was produced in the same manner as Comparative Example 7, except that the thickness of the adhesive composition after drying was changed to 25 μm.

[0415] Various results are shown in Table 1.

[0416] [Comparative Example 9]

[0417] A reinforcing film (C9) was produced in the same manner as Comparative Example 7, except that an annealed PET film was used as the substrate.

[0418] Various results are shown in Table 1.

[0419] [Comparative Example 10]

[0420] A reinforcing film (C10) was produced in the same manner as Comparative Example 8, except that an annealed PET film was used as the substrate.

[0421] Various results are shown in Table 1.

[0422] [Comparative Example 11]

[0423] A reinforcing film (C11) was produced in the same manner as Comparative Example 7, except that a polyimide (PI) film with a thickness of 50 μm (manufactured by Toray DuPont, product name "Kapton 200H") was used as the substrate.

[0424] Various results are shown in Table 1.

[0425] [Comparative Example 12]

[0426] A reinforcing film (C12) was produced in the same manner as Comparative Example 8, except that a polyimide (PI) film with a thickness of 50 μm (manufactured by Toray DuPont, product name "Kapton 200H") was used as the substrate.

[0427] Various results are shown in Table 1.

[0428]

[0429] [Industrial Applicability]

[0430] The reinforcing film according to an embodiment of the present invention is preferably used to reinforce, for example, optical members or electronic members. Explanation of the symbols

[0431] 100 Reinforcement Film 10 base layer 20 adhesive layers

Claims

Claim 1 A reinforcing film comprising a substrate layer and an adhesive layer, wherein the adhesive layer is composed of an acrylic adhesive, wherein the acrylic adhesive is formed from a photocurable acrylic adhesive composition or a thermosetting acrylic adhesive composition, wherein the photocurable acrylic adhesive composition contains an acrylic polymer (P1) and an acrylic oligomer, wherein the thermosetting acrylic adhesive composition contains an acrylic polymer (P2) and an acrylic oligomer, wherein the glass transition temperature of the acrylic polymer (P1) is -70°C to -35°C and the glass transition temperature of the acrylic polymer (P2) is -70°C to -40°C, wherein the acrylic oligomer is an essential component of a (meth)acrylic acid ester having a non-aromatic aliphatic ring in its molecule, wherein the surface elastic modulus of the adhesive layer at 25°C is 50kPa to 1000kPa, and wherein the reinforcing film is subjected to 180°C for 5 minutes A reinforcing film having a heating shrinkage rate of 1.0% or less in the MD direction when heated. Claim 2 A reinforcing film according to claim 1, wherein the adhesive strength to the polyimide film at 25°C is 5.0 N / 25 mm or more. Claim 3 A reinforcing film according to claim 1, having a transmittance of 80% or more at a wavelength of 550 nm. Claim 4 A reinforcing film according to claim 1, wherein the acrylic adhesive is a photocurable acrylic adhesive. Claim 5 A reinforcing film according to claim 1, wherein the storage modulus G' of the adhesive layer at -20℃ is 80kPa to 300kPa. Claim 6 An optical member comprising a reinforcing film as described in any one of claims 1 to 5. Claim 7 An electronic member comprising a reinforcing film described in any one of claims 1 to 5.

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