Reinforcement film

Abstract

To provide a reinforcement film to be used in reinforcing a component, the reinforcement film allowing easy adhesion of a self-adhesive film having requirement features of a portion where an excellent flexibility of the component is required and a portion where an excellent inspectability thereof is required, onto the respective portions.SOLUTION: In a reinforcement film, two or more self-adhesive films are arranged between one release liner and one protective film to have some gaps therebetween. Each of the two or more self-adhesive films includes a substrate layer and an adhesive layer. The adhesive layer of each of the two or more self-adhesive films is directly laminated on the one release liner. The two or more self-adhesive films include: at least one self-adhesive film (I) with a flexure recovery angle being 35 degrees or more; and at least one self-adhesive film (II) with light transmissivity at 550 nm being 80% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a reinforced film. Preferably, the present invention relates to a reinforced film suitable for use in optical components. [Background technology]

[0002] BACKGROUND ART Pressure-sensitive adhesive films comprising a substrate layer and a pressure-sensitive adhesive layer are used to reinforce members of various shapes.

[0003] For example, when joining an integrated circuit (IC) or a flexible printed circuit (FPC) to a semiconductor element substrate (e.g., a TFT substrate), thermocompression bonding is usually performed using an anisotropic conductive film (ACF). Before performing such thermocompression bonding, an adhesive film may be attached to the back side of the semiconductor element substrate to reinforce it (e.g., Patent Document 1).

[0004] In addition, a manufacturing method for so-called flexible devices such as foldable devices and rollable devices, which have been developed in recent years, generally involves forming a release layer and a flexible film substrate on a support substrate such as glass, forming a TFT substrate on the film substrate, and then forming an organic EL layer on top of that. The support substrate is then peeled off to manufacture the flexible device, but because the flexible display layer is very thin, problems with the device can occur due to handling, etc. For this reason, an adhesive film is sometimes attached to the back side to reinforce it (for example, Patent Document 2).

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

[0006] Furthermore, when an integrated circuit (IC) or flexible printed circuit board (FPC) is bonded to a semiconductor element substrate (such as a TFT substrate) by thermocompression bonding, the bonding position is confirmed from the backside of the substrate before bonding. After bonding, the film is inspected for any lifting or deformation. For this reason, the adhesive film that is bonded to the backside of the substrate must be transparent.

[0007] As mentioned above, the adhesive film to be attached to the backside of the substrate must have good flexibility and good inspectability, but it is difficult to achieve both of these required properties at the same time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 5600039 [Patent Document 2] Patent No. 6376271 Summary of the Invention [Problem to be solved by the invention]

[0009] After extensive research into the above-mentioned conventional problems, the inventors of the present invention have noticed that in semiconductor element substrates and flexible devices, the areas requiring good flexibility (for example, the areas where flexible display elements are mounted) are often different from the areas requiring good inspectability (for example, the areas where drive elements are mounted). They then thought that if adhesive films having the required characteristics for each of these areas could be easily attached to the respective locations, the above-mentioned conventional problems could be solved.

[0010] The object of the present invention is to provide a reinforcing film used to reinforce a component, which can easily be attached to each location of an adhesive film having the required characteristics for both the area where good flexibility is required and the area where good inspectability is required. [Means for solving the problem]

[0011] The reinforcement film according to an embodiment of the present invention comprises: A reinforcing film in which two or more adhesive films are arranged with a gap between one release liner and one protective film, Each of the two or more PSA films comprises a base layer and a PSA layer, the PSA layers of the two or more PSA films are directly laminated to one release liner, The two or more PSA films include at least one PSA film (I) having a flex recovery angle of 35 degrees or more and at least one PSA film (II) having a light transmittance at 550 nm of 80% or more.

[0012] In one embodiment, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (I) has a storage modulus of 1.0 × 10 at 85°C. 5 It is less than Pa.

[0013] In one embodiment, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (II) has a storage modulus at 170°C of 5.0 × 10 3 Pa or more 5.0×10 5 Pa is less than.

[0014] In one embodiment, the area of ​​the PSA film (I) is larger than the area of ​​the PSA film (II).

[0015] In one embodiment, the reinforcing film is a reinforcing film for an optical member. [Effects of the Invention]

[0016] According to the present invention, a reinforcing film can be provided which is used to reinforce a component, and which allows adhesive films having the required characteristics for areas of the component where good flexibility is required and areas where good inspectability is required to be easily attached to the respective locations. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic cross-sectional view of a reinforced film according to one embodiment of the present invention. [Figure 2] 1 is a schematic plan view of one embodiment of the reinforcing film of the present invention with the release liner removed. FIG. [Figure 3] FIG. 2 is a schematic plan view of another embodiment of the reinforcing film of the present invention with the release liner removed. DETAILED DESCRIPTION OF THE INVENTION

[0018] In this specification, the term "(meth)acrylic" means "acrylic and / or methacrylic," the term "(meth)acrylate" means "acrylate and / or methacrylate," the term "(meth)allyl" means "allyl and / or methallyl," and the term "(meth)acrolein" means "acrolein and / or methacrolein." Furthermore, in this specification, the term "acid (salt)" means "acid and / or its salt." Examples of salts include alkali metal salts and alkaline earth metal salts, and specific examples include sodium salts and potassium salts.

[0019] <<A. Reinforcing film>> A reinforced film according to an embodiment of the present invention is a reinforced film in which two or more adhesive films are arranged with a gap between one release liner and one protective film, and each of the two or more adhesive films includes a base layer and an adhesive layer, and the adhesive layers of the two or more adhesive films are directly laminated to the one release liner.

[0020] The number of adhesive films arranged so as to leave a gap between one release liner and one protective film is two or more, preferably two to ten, more preferably two to five, even more preferably two to four, and particularly preferably two to three.

[0021] A schematic cross-sectional view of one embodiment of the reinforced film of the present invention is shown in Figure 1. Figure 1 shows an embodiment in which two PSA films are arranged with a gap between one release liner and one protective film. As shown in Figure 1, reinforced film 1000 has PSA films 300a and 300b arranged with a gap L between release liner 100 and protective film 200. PSA film 300a includes a base layer 10a and a PSA layer 20a. PSA film 300b includes a base layer 10b and a PSA layer 20b.

[0022] The distance L is preferably 0.1 mm to 5.0 mm, more preferably 0.2 mm to 3.0 mm, even more preferably 0.3 mm to 2.0 mm, particularly preferably 0.5 mm to 1.5 mm, and most preferably 0.7 mm to 1.5 mm.

[0023] The PSA films may be arranged in any suitable manner so long as they are spaced apart between one release liner and one protective film, without impairing the effects of the present invention. That is, two or more PSA films may be arranged with a gap between them, corresponding to the arrangement of the respective portions (particularly portions requiring good flexibility and portions requiring good inspectability) of the members (e.g., optical members) to be bonded together, depending on the required properties of those portions.

[0024] Figure 2 is a schematic plan view of one embodiment of the reinforcing film of the present invention with the release liner removed. Figure 2 shows an embodiment in which two adhesive films are arranged with a gap between them. In Figure 2, adhesive film 300a and adhesive film 300b are arranged on protective film 200 with gap L between them.

[0025] Figure 3 is a schematic plan view of another embodiment of the reinforcing film of the present invention with the release liner removed. Figure 3 shows an embodiment in which three adhesive films are arranged with gaps between them. In Figure 3, adhesive film 300a and adhesive films 300b and 300c are arranged on protective film 200 with gaps L1 and L2 between them.

[0026] The reinforcing film according to the embodiment of the present invention may have any appropriate other layer within a range that does not impair the effects of the present invention. The other layer may be one type only, or may be two or more types. Examples of the other layer include an antistatic layer, which will be described later.

[0027] At least one of the two or more PSA films included in the reinforcing film according to an embodiment of the present invention is a PSA film (I) having a flex recovery angle of 35 degrees or more. The flex recovery angle is preferably 40 degrees or more, more preferably 50 degrees or more, even more preferably 70 degrees or more, particularly preferably 100 degrees or more, and most preferably 120 degrees or more. The upper limit of the flex recovery angle is preferably 180 degrees or less. PSA films having a flex recovery angle within the above range can be preferably applied to areas requiring good flexibility. For example, the formation of creases or winding marks in the foldable or windable areas of a foldable or windable device can be effectively suppressed. If the flex recovery angle is too small outside the above range, the film may not be applicable to areas requiring good flexibility. The method for measuring the flex recovery angle will be described later.

[0028] A pressure-sensitive adhesive film (I) having a flex recovery angle of 35 degrees or more can be achieved, for example, by appropriately selecting the base layer (I) and the pressure-sensitive adhesive layer (I).

[0029] At least one of the two or more PSA films included in the reinforcing film according to an embodiment of the present invention is a PSA film (II) having a light transmittance at 550 nm of 80% or more. The light transmittance is preferably 83% or more, more preferably 85% or more, even more preferably 88% or more, and particularly preferably 90% or more. The upper limit of the light transmittance is preferably 100% or less. PSA films having a light transmittance within the above range can be preferably applied to areas where good inspectability is required. For example, they can maintain good inspectability after IC bonding. If the light transmittance is too low outside the above range, they may not be applicable to areas where good inspectability is required. The method for measuring the light transmittance will be described later.

[0030] A pressure-sensitive adhesive film (II) having a light transmittance of 80% or more at 550 nm can be realized, for example, by appropriately selecting the base layer (II) and the pressure-sensitive adhesive layer (II).

[0031] The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (I) preferably has a storage modulus at 85°C of 1.0 x 10 5 Pa, more preferably less than 8.0 × 10 4 Pa, and more preferably less than 5.0 × 10 4 Pa, and particularly preferably 2.0 × 10 4 In practice, the lower limit of the storage modulus at 85°C is preferably less than 1.0 × 10 3 The storage modulus at 85°C is 0.01 Pa or more. If the storage modulus at 85°C is within the above range, it can be more preferably applied to areas where good flexibility is required. For example, the occurrence of creases or winding marks in areas of a foldable or rollable device can be more effectively suppressed. If the storage modulus at 85°C is too low outside the above range, it may not be applicable to areas where good flexibility is required. The method for measuring the storage modulus at 85°C will be described later.

[0032] The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (II) preferably has a storage modulus at 170°C of 5.0 x 103 Pa or more 5.0×10 5 and more preferably less than 7.5 × 10 3 Pa or more 2.5×10 5 and more preferably less than 1.0 × 10 4 Pa or more 1.0×10 5 The storage modulus at 170°C is less than this range. If the storage modulus at 170°C is within this range, it can be more preferably applied to parts requiring good inspectability. For example, it can better maintain inspectability after IC bonding. If the storage modulus at 170°C is outside this range, that is, if it is too high or too low, it may be prone to air bubbles during IC bonding, making it unsuitable for parts requiring good inspectability. The method for measuring the storage modulus at 170°C will be described later.

[0033] The area of ​​the adhesive film (I) (or the total area if there are multiple adhesive films (I)) and the area of ​​the adhesive film (II) (or the total area if there are multiple adhesive films (II)) can be appropriately set according to the size of the area requiring good flexibility and the area requiring good inspectability. For example, in the case of a device that can be bent or rolled up, the area of ​​the area where the flexible display element is mounted (the area requiring good flexibility) is typically larger than the area of ​​the area where the drive element is mounted (the area requiring good inspectability). In such a case, the area of ​​the adhesive film (I) (or the total area if there are multiple adhesive films (I)) is preferably larger than the area of ​​the adhesive film (II) (or the total area if there are multiple adhesive films (II)).

[0034] In the reinforced film according to an embodiment of the present invention, the release liner is preferably peeled off, and then the exposed pressure-sensitive adhesive layer is attached to a member (e.g., an optical member) to be attached, and then the protective film is peeled off. Therefore, in order to facilitate the attachment operation, the release strength (A) of the release liner is preferably smaller than the release strength (B) of the protective film relative to a common pressure-sensitive adhesive film. If the release strength (A) of the release liner is larger than the release strength (B) of the protective film relative to a common pressure-sensitive adhesive film, there is a risk of peeling between the protective film and the pressure-sensitive adhesive film when attempting to peel the release liner from the pressure-sensitive adhesive film.

[0035] The release strength (A) of the release liner is preferably 0 gf / 25 mm or more and 10 gf / 25 mm or less, more preferably 0 gf / 25 mm or more and 8 gf / 25 mm or less, and even more preferably 0 gf / 25 mm or more and 5 gf / 25 mm or less.

[0036] The peel strength (B) of the protective film is preferably 2 gf / 25 mm or more and less than 15 gf / 25 mm, and more preferably 2.5 gf / 25 mm or more and less than 12 gf / 25 mm.

[0037] The reinforced film according to the embodiment of the present invention can be used in various applications. The reinforced film according to the embodiment of the present invention is typically used as a reinforced film for optical components, as it can more effectively utilize the effects of the present invention. The reinforced film according to the embodiment of the present invention can be particularly suitably used in flexible devices such as bendable devices having movable bending portions, foldable devices, and rollable devices.

[0038] <A-1. Adhesive film> The reinforcing film according to an embodiment of the present invention includes two or more adhesive films. At least one of the two or more adhesive films included in the reinforcing film according to an embodiment of the present invention is an adhesive film (I) having a bending recovery angle of 35 degrees or more, and at least one is an adhesive film (II) having a light transmittance of 80% or more at 550 nm.

[0039] The adhesive film includes a base material layer and an adhesive layer. That is, the adhesive film (I) includes a base material layer (I) and an adhesive layer (I), and the adhesive film (II) includes a base material layer (II) and an adhesive layer (II).

[0040] In addition to the base material layer and the adhesive layer, the adhesive film may have any other appropriate layer as long as the effects of the present invention are not impaired. The other layer may be only one type or two or more types. Examples of the other layer include an antistatic layer described later.

[0041] The thicknesses of the two or more adhesive films included in the reinforcing film according to an embodiment of the present invention may be the same, or at least one may have a different thickness. From the viewpoint of ease of handling, etc., it is preferable that the thicknesses of the two or more adhesive films included in the reinforcing film according to an embodiment of the present invention are the same.

[0042] <A-1-1. Base material layer> In this specification, when simply referred to as the "base material layer", it means including any of the base material layers included in the two or more adhesive films included in the reinforcing film according to an embodiment of the present invention (that is, including both the base material layer (I) and the base material layer (II)).

[0043] The thickness of the base material layer is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, still more preferably 10 μm to 100 μm, particularly preferably 15 μm to 90 μm, and most preferably 20 μm to 85 μm. If the thickness of the base material layer is within the above range, the effects of the present invention can be more manifested.

[0044] Any suitable material can be used as the material for the substrate layer as long as it can exhibit the effects of the present invention as a component of the PSA film. Typical examples of such substrate layer materials include resin materials.

[0045] Examples of resin materials for the substrate layer include acrylic resins such as polyimide (PI), polyether ether ketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polymethyl methacrylate (PMMA), as well as polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluorine-based resins, cyclic olefin polymer (COP), and polycarbonate (PC). The substrate layer may be made of one type of resin material or two or more types of resin materials.

[0046] In the reinforcing film according to an embodiment of the present invention, in order to further exhibit the effects of the present invention, it is preferable that the base layer (I) contained in the adhesive film (I) and the base layer (II) contained in the adhesive film (II) have different physical properties and are made of different materials.

[0047] The substrate layer (I) preferably has a Young's modulus at 23°C of 6.0 x 10 7 Pa or more, more preferably 1.0×10 8 Pa or more, and more preferably 5.0 × 10 8 Pa or more, and particularly preferably 8.0 × 10 8 Pa or more, and most preferably 1.0×10 9 The upper limit of the Young's modulus of the base layer (I) at 23°C is typically preferably 1.0 × 10 11Pa or less. If the Young's modulus of the base layer (I) at 23°C is within the above range, the PSA film (I) can be preferably applied to areas requiring good flexibility. For example, the formation of creases and winding marks in the foldable or windable areas of a foldable or windable device can be effectively suppressed. If the Young's modulus of the base layer (I) at 23°C is too low, when the PSA film (I) is bent at an angle, the tension on the outer diameter side may not be sufficiently maintained against the compression on the inner diameter side, which may make the thickness more likely to change and cause lifting from the adherend. If the Young's modulus of the base layer (I) at 23°C is too high, the PSA film (I) may not be easily deformed. The method for measuring Young's modulus will be described later.

[0048] In order to further exert the effects of the present invention, the resin material used for the base layer (I) is preferably at least one selected from polyimide (PI), polyethylene terephthalate (PET), and triacetyl cellulose (TAC).

[0049] The substrate layer (II) preferably has a transmittance at 550 nm of 80% or more, more preferably 83% or more, even more preferably 85% or more, particularly preferably 88% or more, and most preferably 90% or more. If the transmittance at 550 nm of the substrate layer (II) is within the above range, the PSA film (II) can be preferably applied to areas requiring good inspectability. For example, inspectability after IC bonding can be better maintained. If the transmittance at 550 nm of the substrate layer (II) is outside the above range and is too high or too low, it may not be applicable to areas requiring good inspectability. The method for measuring the transmittance at 550 nm will be described later.

[0050] In terms of being able to more effectively exhibit the effects of the present invention, the resin material for the substrate layer (II) is preferably polyethylene terephthalate (PET).

[0051] The base material layer may contain any appropriate additive as long as the effects of the present invention are not impaired. The base material layer may be subjected to any appropriate surface treatment as long as the effects of the present invention are not impaired.

[0052] <A-1-2. Adhesive layer> In this specification, when simply referred to as the "adhesive layer", it means any of the adhesive layers included in two or more adhesive films contained in the reinforcing film according to the embodiment of the present invention (that is, it includes both the adhesive layer (I) and the adhesive layer (II)).

[0053] The thickness of the adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, still 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 more effectively manifested.

[0054] The adhesive layer is composed of an adhesive. As the adhesive constituting the adhesive layer, an acrylic adhesive is preferred.

[0055] The acrylic adhesive is formed from an acrylic adhesive composition.

[0056] The acrylic adhesive can thus be defined as being formed from an acrylic adhesive composition. This is because it is impossible to directly identify the acrylic adhesive by its structure since the acrylic adhesive composition undergoes a crosslinking reaction or the like by heating or ultraviolet irradiation to become the acrylic adhesive, and there is a situation where it is approximately not practical ("impossible and non-practical situation"). Therefore, by defining it as "formed from an acrylic adhesive composition", the acrylic adhesive is properly identified as a "substance".

[0057] The adhesive strength of the acrylic adhesive to glass at 23°C, peel speed 300 mm / min, peel angle 180° is preferably 5 N / 25 mm or more, more preferably 7 N / 25 mm or more, even more preferably 8 N / 25 mm or more, particularly preferably 10 N / 25 mm or more, and most preferably 15 N / 25 mm or more. The upper limit of the adhesive strength is usually the higher the better, but taking into consideration the balance with other adhesive properties, it is preferably 50 N / 25 mm or less. Adjusting the adhesive strength within the above range allows the film to function favorably as a reinforcing film. The method for measuring the adhesive strength will be described later.

[0058] Any appropriate method can be adopted as a method for forming the acrylic pressure-sensitive adhesive as long as the effects of the present invention are not impaired. Examples of methods for forming such an acrylic pressure-sensitive adhesive include a method in which an acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, heated or dried as necessary, and cured as necessary to form the acrylic pressure-sensitive adhesive into a sheet on the substrate.

[0059] Any appropriate means can be used to apply the acrylic pressure-sensitive adhesive composition as long as the effects of the present invention are not impaired. Examples of such application means include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0060] The acrylic pressure-sensitive adhesive composition can be heated or dried by any appropriate means as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to 60°C to 180°C, or performing an aging treatment at a temperature around room temperature.

[0061] The acrylic pressure-sensitive adhesive composition can be cured by any appropriate means as long as the effects of the present invention are not impaired, including, for example, heat, ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0062] A typical method for forming an acrylic pressure-sensitive adhesive from an acrylic pressure-sensitive adhesive composition is (1) A method for forming a photocurable acrylic pressure-sensitive adhesive by photocuring a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator; (2) A method for forming a thermosetting acrylic pressure-sensitive adhesive by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer prepared by solution polymerization using a thermal polymerization initiator; Examples include:

[0063] That is, typical examples of acrylic adhesives include: (1) A photocurable acrylic pressure-sensitive adhesive formed by a photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (typically, an acrylic partial polymer) (P1) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator; (2) A thermosetting acrylic pressure-sensitive adhesive formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P2) prepared by solution polymerization using a thermal polymerization initiator; Examples include:

[0064] [A-1-2-1. Acrylic polymer (P1)] One embodiment of the acrylic polymer is an acrylic polymer (P1) prepared by polymerization (typically, partial polymerization) using a photopolymerization initiator. As a method for polymerization using a photopolymerization initiator, any appropriate method, such as a conventionally known method, can be used as long as it does not impair the effects of the present invention. Polymerization using a photopolymerization initiator is typically carried out by irradiation with light such as UV.

[0065] The acrylic polymer (P1) is preferably an acrylic partial polymer (sometimes referred to as an acrylic prepolymer). The acrylic partial polymer is different from one obtained as a complete polymer of the monomer components (preferably a polymer with a polymerization conversion rate of more than 95% by weight), and is a partial polymer obtained by reducing the polymerization conversion rate of the monomer components to preferably 95% by weight or less.

[0066] The polymerization conversion rate of the acrylic partial polymer is preferably 70% by weight or less, more preferably 60% by weight or less, even more preferably 50% by weight or less, particularly preferably 40% by weight or less, and most preferably 35% by weight or less. The lower limit of the polymerization conversion rate of the acrylic partial polymer is preferably 1% by weight or more, more preferably 5% by weight or more.

[0067] The acrylic polymer (P1) is obtained by polymerizing a monomer component (M1). The monomer component (M1) does not include a crosslinking agent, which may be contained in the acrylic pressure-sensitive adhesive composition and will be described later. When obtaining the acrylic polymer (P1) by polymerization, in addition to the monomer component (M1) and the photopolymerization initiator, any appropriate additive may be used as long as it does not impair the effects of the present invention.

[0068] The acrylic polymer (P1) can be defined as something obtained by polymerizing the monomer component (M1) in this way. This is because the acrylic polymer (P1) becomes the acrylic polymer (P1) through the polymerization reaction of the monomer component (M1), and there are circumstances that make it impossible and almost impractical to directly identify the acrylic polymer (P1) by its structure ("impossible / impractical circumstances"). Therefore, the acrylic polymer (P1) is appropriately defined as a "product" by the definition of "something obtained by polymerizing the monomer component (M1)."

[0069] In order to further exert the effects of the present invention, the acrylic polymer (P1) preferably has a Tg of −70° C. to 50° C., more preferably −60° C. to 40° C., even more preferably −55° C. to 30° C., and particularly preferably −50° C. to 20° C. By adjusting the Tg of the acrylic polymer (P1) to fall within the above specific range, the effects of the present invention can be further exerted.

[0070] The Tg of the acrylic polymer (P1) is a value calculated from the Fox equation based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P1) and the weight fraction (copolymerization ratio by weight) of the monomer. The Fox equation, as shown below, is a relational expression between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer. 1 / Tg=Σ(Wi / Tgi)

[0071] In the Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), and Tgi is the glass transition temperature (unit: K) of the homopolymer of monomer i. As the Tg of the homopolymer, a value listed in publicly available documents is adopted.

[0072] As the Tg of the homopolymer, for example, the following specific values ​​can be used: n-Butyl acrylate (BA): -55℃ Lauryl acrylate (LA): -23℃ 2-Ethylhexyl acrylate (2EHA): -70℃ 2-Hydroxyethyl acrylate (2HEA): -15°C 4-Hydroxybutyl acrylate (4HBA): -40°C N-vinyl-2-pyrrolidone (NVP): 80℃ Methyl methacrylate (MMA): 105℃

[0073] For the Tg of homopolymers other than those exemplified above, the values ​​listed in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When multiple values ​​are listed in the "Polymer Handbook," the conventional value is used. For monomers not listed in the "Polymer Handbook," the catalog value from the monomer manufacturer is used. For the Tg of homopolymers of monomers not listed in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP 2007-51271 A is used.

[0074] The monomer component (M1) preferably contains an alkyl (meth)acrylate (a1) and a polar group-containing monomer (b1). The alkyl (meth)acrylate (a1) may be of one type or two or more types. The polar group-containing monomer (b1) may be of one type or two or more types.

[0075] The alkyl group in the ester moiety of the alkyl (meth)acrylate (a1) (hereinafter sometimes referred to as the "alkyl group in the ester moiety") does not include alkyl groups containing a hydroxyl group or alkyl groups containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a1) is clearly distinguished from the polar group-containing monomer (b1).

[0076] The content of the alkyl (meth)acrylate (a1) in the monomer component (M1) is preferably 40% by weight to 99% by weight, more preferably 45% by weight to 90% by weight, even more preferably 50% by weight to 80% by weight, and particularly preferably 60% by weight to 75% by weight, in order to further exhibit the effects of the present invention.

[0077] The alkyl group in the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 18 carbon atoms, even more preferably an alkyl group having 2 to 16 carbon atoms, particularly preferably an alkyl group having 3 to 14 carbon atoms, and most preferably an alkyl group having 6 to 14 carbon atoms, in terms of being able to further exert the effects of the present invention.

[0078] The alkyl group of the ester moiety is preferably a chain alkyl group, which can further exert the effects of the present invention. Here, chain alkyl group means both linear and branched.

[0079] Examples of the alkyl(meth)acrylate (a1) in which the alkyl group in the ester moiety is a chain alkyl group having 1 to 20 carbon atoms include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, s-butyl(meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, and isopropyl(meth)acrylate. Examples of such acrylates include isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate.

[0080] In order to further demonstrate the effects of the present invention, the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1) preferably has a glass transition temperature (Tg) of its homopolymer (homopolymer) of −10° C. or lower, more preferably −12° C. or lower, even more preferably −15° C. or lower, particularly preferably −18° C. or lower, and most preferably −20° C. or lower. The lower limit of the glass transition temperature (Tg) is preferably −80° C. or higher. The glass transition temperature (Tg) of the homopolymer (homopolymer) of the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1) can affect the adhesive properties of the acrylic polymer (P1). The effects of the present invention can be further demonstrated by using an alkyl(meth)acrylate whose homopolymer (homopolymer) has a glass transition temperature (Tg) within the above range as the alkyl(meth)acrylate (a1) that can be contained in the monomer component (M1).

[0081] Here, the glass transition temperature Tg of a homopolymer of alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) can be a value described in a publicly known document, such as the value described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989). When multiple values ​​are described in the "Polymer Handbook," the conventional value is used. For alkyl (meth)acrylates not described in the "Polymer Handbook," the value listed in the catalog of the monomer manufacturer is used. For alkyl (meth)acrylate homopolymers not described in the "Polymer Handbook" and for which no catalog value is provided by the monomer manufacturer, the value obtained by the measurement method described in JP 2007-51271 A is used.

[0082] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) preferably contains an alkyl (meth)acrylate (a1-1) whose homopolymer has a glass transition temperature Tg in the range of −40° C. to −10° C. (preferably −35° C. to −15° C., more preferably −30° C. to −20° C.) Inclusion of the alkyl (meth)acrylate (M1) in the alkyl (meth)acrylate (a1-1) allows the effects of the present invention to be further enhanced.

[0083] An example of the alkyl(meth)acrylate (a1-1) is lauryl acrylate (LA) (the glass transition temperature Tg of its homopolymer is −23° C.).

[0084] The content of the alkyl (meth)acrylate (a1-1) in the total amount of alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 0 to 90% by weight, more preferably 10 to 80% by weight, even more preferably 20 to 70% by weight, and particularly preferably 30 to 60% by weight, in order to further exhibit the effects of the present invention.

[0085] The content of the alkyl (meth)acrylate (a1-1) in the total amount of the monomer component (M1) is preferably 0 to 70% by weight, more preferably 10 to 60% by weight, even more preferably 20 to 50% by weight, and particularly preferably 30 to 45% by weight, in order to further exhibit the effects of the present invention.

[0086] In order to further enhance the effects of the present invention, the alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) preferably contains an alkyl (meth)acrylate (a1-2) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.). When the alkyl (meth)acrylate (M1) contains the alkyl (meth)acrylate (a1-2), the effects of the present invention can be further enhanced.

[0087] An example of the alkyl(meth)acrylate (a1-2) is 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer is −70° C.).

[0088] The content of the alkyl (meth)acrylate (a1-2) in the total amount of alkyl (meth)acrylate (a1) that can be contained in the monomer component (M1) is preferably 20% by weight to 90% by weight, more preferably 30% by weight to 80% by weight, even more preferably 40% by weight to 70% by weight, and particularly preferably 50% by weight to 65% by weight, in order to further exhibit the effects of the present invention.

[0089] The content of the alkyl (meth)acrylate (a1-2) in the total amount of the monomer component (M1) is preferably 10% by weight to 100% by weight, more preferably 20% by weight to 90% by weight, even more preferably 30% by weight to 80% by weight, and particularly preferably 40% by weight to 70% by weight, in order to further exhibit the effects of the present invention.

[0090] The content of the polar group-containing monomer (b1) in the monomer component (M1) is preferably 1 to 50% by weight, more preferably 1 to 40% by weight, even more preferably 1 to 30% by weight, and particularly preferably 1 to 20% by weight, in order to further exhibit the effects of the present invention.

[0091] In order to further exert the effects of the present invention, the polar group-containing monomer (b1) preferably contains at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, and more preferably contains both a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0092] The hydroxyl group-containing monomer (b1-1) may be of one type only, or of two or more types.

[0093] Examples of the hydroxyl group-containing monomer (b1-1) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate; and N-hydroxyethyl (meth)acrylamide.

[0094] In order to further exert the effects of the present invention, the hydroxyl-containing monomer (b1-1) preferably has a glass transition temperature Tg of its homopolymer of -60°C to -10°C, more preferably -55°C to -10°C, and even more preferably -45°C to -10°C. The glass transition temperature Tg of the homopolymer of the hydroxyl-containing monomer (b1-1) can affect the adhesive properties of the acrylic polymer (P1). The effects of the present invention can be further exerted by using a hydroxyl-containing monomer whose homopolymer has a glass transition temperature Tg within the above range as the hydroxyl-containing monomer (b1-1) that can be contained in the monomer component (M1).

[0095] The glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1-1) can be determined by the same explanation as for the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1).

[0096] In terms of further exerting the effects of the present invention, the hydroxyl group-containing monomer (b1-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), and particularly preferably 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C).

[0097] The content of the hydroxyl group-containing monomer (b1-1) in the polar group-containing monomer (b1) is preferably 10% by weight to 100% by weight, more preferably 20% by weight to 90% by weight, even more preferably 30% by weight to 85% by weight, and particularly preferably 40% by weight to 80% by weight, in order to further exhibit the effects of the present invention.

[0098] The content of the hydroxyl group-containing monomer (b1-1) in the monomer component (M1) is preferably 0 to 80% by weight, more preferably 10 to 70% by weight, even more preferably 20 to 60% by weight, and particularly preferably 30 to 50% by weight, in order to further exhibit the effects of the present invention.

[0099] The monomer (b1-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0100] Examples of the monomer (b1-2) having a polar group other than a hydroxyl group include N-vinyl-2-pyrrolidone, nitrogen-containing monomers other than N-vinyl-2-pyrrolidone, carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, acid anhydride group-containing monomers, vinyl esters (e.g., vinyl acetate (VAc), vinyl propionate, vinyl laurate), aromatic vinyl compounds, amide group-containing monomers, epoxy group-containing monomers, (meth)acryloylmorpholine, and vinyl ethers.

[0101] Examples of carboxy group-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0102] Examples of nitrogen-containing monomers other than N-vinyl-2-pyrrolidone include nitrogen-containing vinyl monomers such as methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, and N-vinylcaprolactam; and cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile.

[0103] In order to further exert the effects of the present invention, the glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group is preferably −30° C. to 100° C., more preferably −20° C. to 95° C., and even more preferably −10° C. to 90° C. The glass transition temperature Tg of the homopolymer of the monomer (b1-2) having a polar group other than a hydroxyl group can affect the adhesive properties of the acrylic polymer (P1). The effects of the present invention can be further exerted by using, as the monomer (b1-2) having a polar group other than a hydroxyl group that can be contained in the monomer component (M1), a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg within the above range.

[0104] As the monomer (b1-2) having a polar group other than a hydroxyl group, a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg of 50° C. to 100° C. is preferred, as it can further exhibit the effects of the present invention. The glass transition temperature Tg of the homopolymer of this monomer is preferably 60° C. to 95° C., and more preferably 70° C. to 90° C.

[0105] With regard to the glass transition temperature Tg of a homopolymer of a monomer (b1-2) having a polar group other than a hydroxyl group, the explanation of the glass transition temperature Tg of a homopolymer of an alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [A-1-2-1. Acrylic polymer (P1)] may be cited.

[0106] In terms of further exerting the effects of the present invention, the monomer (b1-2) having a polar group other than a hydroxyl group is preferably N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80°C).

[0107] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the polar group-containing monomer (b1) is preferably 0% by weight to 90% by weight, more preferably 10% by weight to 80% by weight, even more preferably 15% by weight to 70% by weight, and particularly preferably 20% by weight to 60% by weight, in order to further exhibit the effects of the present invention.

[0108] The content of the monomer (b1-2) having a polar group other than a hydroxyl group in the monomer component (M1) is preferably 0% by weight to 20% by weight, more preferably 0% by weight to 10% by weight, even more preferably 0% by weight to 9% by weight, and particularly preferably 0% by weight to 8% by weight, in order to further exhibit the effects of the present invention.

[0109] In order to further exert the effects of the present invention, the monomer component (M1) preferably contains an alkyl(meth)acrylate (a1) and at least one selected from the group consisting of a hydroxyl group-containing monomer (b1-1) and a monomer (b1-2) having a polar group other than a hydroxyl group, more preferably contains an alkyl(meth)acrylate (a1), a hydroxyl group-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group, and even more preferably contains a galvanic acid of a homopolymer thereof. The alkyl(meth)acrylate (a1-1) has a glass transition temperature Tg in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), the alkyl(meth)acrylate (a1-2) has a glass transition temperature Tg of its homopolymer in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), a hydroxyl group-containing monomer (b1-1), and a monomer (b1-2) having a polar group other than a hydroxyl group.

[0110] In order to further exert the effects of the present invention, the total content of the alkyl (meth)acrylate (a1-1) whose homopolymer has a glass transition temperature Tg in the range of -40°C to -10°C (preferably -35°C to -15°C, more preferably -30°C to -20°C), the alkyl (meth)acrylate (a1-2) whose homopolymer has a glass transition temperature Tg in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), the hydroxyl group-containing monomer (b1-1), and the monomer having a polar group other than a hydroxyl group (b1-2) in the monomer component (M1) is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0111] In terms of being able to further exert the effects of the present invention, the monomer component (M1) specifically preferably contains lauryl acrylate, 2-ethylhexyl acrylate, 4-hydroxybutyl acrylate, and N-vinyl-2-pyrrolidone.

[0112] The monomer component (M1) may contain another monomer (c1) that does not fall into either the alkyl (meth)acrylate (a1) or the polar group-containing monomer (b1). The other monomer (c1) can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (P1), adjusting the adhesive properties, etc. The other monomer may be one type or two or more types.

[0113] The content of the other monomer (c1) in the monomer component (M1) is preferably 20% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0114] The photopolymerization initiator can be appropriately selected from any appropriate photopolymerization initiator depending on the type of polymerization method, and the photopolymerization initiator may be one type or two or more types.

[0115] Examples of the photopolymerization initiator include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

[0116] Specific examples of the benzoin ether-based photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethan-1-one (a commercially available product is, for example, the trade name "OMNIRAD651" manufactured by IGM Resins BV), and anisole methyl ether.

[0117] Specific examples of acetophenone-based photopolymerization initiators include 1-hydroxycyclohexyl phenyl ketone (a commercially available product is, for example, the trade name "OMNIRAD184" manufactured by IGM Resins BV), 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (a commercially available product is, for example, the trade name "OMNIRAD2959" manufactured by IGM Resins BV), 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone.

[0118] Specific examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)-phenyl]-2-hydroxy-2-methylpropan-1-one, and the like.

[0119] Specific examples of aromatic sulfonyl chloride photopolymerization initiators include 2-naphthalenesulfonyl chloride.

[0120] Specific examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime.

[0121] Specific examples of benzoin-based photopolymerization initiators include benzoin.

[0122] Specific examples of benzyl-based photopolymerization initiators include benzyl.

[0123] Specific examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone.

[0124] Specific examples of the ketal-based photopolymerization initiator include benzyl dimethyl ketal.

[0125] Specific examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone.

[0126] Specific examples of the acylphosphine photopolymerization initiator include bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)(2,4,4-trimethylpentyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-n-butylphosphine oxide, bis(2,6-dimethoxybenzoyl)-(2-methylpropan-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropan-1-yl)phosphine oxide, bis(2,6-dimethoxybenzoyl)-(1-methylpropan-1-yl)phosphine oxide, and bis(2,6-dimethoxybenzoyl)phenylphosphine oxide. Bis(2,6-dimethoxybenzoyl)cyclohexylphosphine oxide, Bis(2,6-dimethoxybenzoyl)octylphosphine oxide, Bis(2-methoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, Bis(2-methoxybenzoyl)(1-methylpropan-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, Bis(2,6-diethoxybenzoyl)(1-methylpropan-1-yl)phosphine oxide Bis(2,6-dibutoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, bis(2,4-dimethoxybenzoyl)(2-methylpropan-1-yl)phosphine oxide, bis(2,4,6-trimethylbenzoyl)(2,4-dipentoxyphenyl)phosphine oxide, bis(2,6-dimethoxybenzoyl)benzylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylpropylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2 -phenylethylphosphine oxide, bis(2,6-dimethoxybenzoyl)benzylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylpropylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2-phenylethylphosphine oxide, 2,6-dimethoxybenzoylbenzylbutylphosphine oxide, 2,6-dimethoxybenzoylbenzyloctylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diisopropylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-4-methylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,5-diethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,3,5,6-tetramethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)isobutylphosphine oxide, 2,6-dimethythoxybenzoyl-2,4,6-trimethylbenzoyl-n-butylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-dibutoxyphenylphosphine oxide, 1,10-bis[bis(2,4,6-trimethylbenzoyl)phosphine oxide]decane, tri(2-methylbenzoyl)phosphine oxide, etc.

[0127] The amount of the photopolymerization initiator used can be set to any appropriate amount as long as it does not impair the effects of the present invention. The amount of the photopolymerization initiator used is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, even more preferably 0.007 to 3 parts by weight, and particularly preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the monomer component (M1), in order to further exhibit the effects of the present invention.

[0128] [A-1-2-2. Acrylic polymer (P2)] One embodiment of the acrylic polymer is an acrylic polymer (P2) prepared by solution polymerization using a thermal polymerization initiator. As a polymerization method using a thermal polymerization initiator, any appropriate method, such as a conventionally known method, can be adopted as long as it does not impair the effects of the present invention.

[0129] The acrylic polymer (P2) is obtained by polymerizing a monomer component (M2). The monomer component (M2) does not include a crosslinking agent, which may be contained in the acrylic pressure-sensitive adhesive composition and will be described later. When obtaining the acrylic polymer (P2) by polymerization, in addition to the monomer component (M2) and the thermal polymerization initiator, any appropriate additive may be used as long as it does not impair the effects of the present invention.

[0130] The acrylic polymer (P2) can be defined as something obtained by polymerizing the monomer component (M2) in this way. This is because the acrylic polymer (P2) becomes the acrylic polymer (P2) through the polymerization reaction of the monomer component (M2), and there are circumstances that make it impossible and almost impractical to directly identify the acrylic polymer (P2) by its structure ("impossible / impractical circumstances"). Therefore, the acrylic polymer (P2) is appropriately defined as a "product" by the definition of "something obtained by polymerizing the monomer component (M2)."

[0131] In order to further exert the effects of the present invention, the acrylic polymer (P2) preferably has a Tg of −70° C. to 50° C., more preferably −60° C. to 40° C., even more preferably −55° C. to 30° C., and particularly preferably −50° C. to 20° C. By adjusting the Tg of the acrylic polymer (P2) to fall within the above specific range, the effects of the present invention can be further exerted.

[0132] The Tg of the acrylic polymer (P2) refers to the value calculated from the Fox formula based on the Tg of the homopolymer of each monomer constituting the acrylic polymer (P2) and the weight fraction (copolymerization ratio by weight) of the monomer. The Fox formula and the Tg of various homopolymers can be found in the explanation in the section [A-1-2-1. Acrylic polymer (P1)].

[0133] The monomer component (M2) preferably contains an alkyl (meth)acrylate (a2) and a polar group-containing monomer (b2). The alkyl (meth)acrylate (a2) may be of one type or two or more types. The polar group-containing monomer (b2) may be of one type or two or more types.

[0134] The alkyl group in the ester moiety of the alkyl (meth)acrylate (a2) (hereinafter sometimes referred to as the "alkyl group in the ester moiety") does not include an alkyl group containing a hydroxyl group or an alkyl group containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a2) is clearly distinguished from the polar group-containing monomer (b2).

[0135] The content of the alkyl (meth)acrylate (a2) in the monomer component (M2) is preferably 40% by weight to 99% by weight, more preferably 45% by weight to 90% by weight, even more preferably 50% by weight to 80% by weight, and particularly preferably 60% by weight to 75% by weight, in order to further exhibit the effects of the present invention.

[0136] The alkyl group in the ester moiety is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 18 carbon atoms, even more preferably an alkyl group having 1 to 16 carbon atoms, and particularly preferably an alkyl group having 1 to 14 carbon atoms, in terms of being able to further exert the effects of the present invention.

[0137] The alkyl group of the ester moiety is preferably a chain alkyl group, which can further exert the effects of the present invention. Here, chain alkyl group means both linear and branched.

[0138] For the alkyl(meth)acrylate (a2) in which the alkyl group in the ester moiety is a chain alkyl group having 1 to 20 carbon atoms, the explanation for the alkyl(meth)acrylate (a1) in which the alkyl group in the ester moiety is a chain alkyl group having 1 to 20 carbon atoms in the section [A-1-2-1. Acrylic polymer (P1)] can be cited.

[0139] In order to further exert the effects of the present invention, the alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) preferably contains an alkyl (meth)acrylate (a2-1) whose homopolymer has a glass transition temperature Tg in the range of −80° C. to −60° C. (preferably −75° C. to −60° C., more preferably −75° C. to −65° C.) Inclusion of the alkyl (meth)acrylate (a2-1) in the alkyl (meth)acrylate (M2) allows the effects of the present invention to be further exerted.

[0140] An example of the alkyl(meth)acrylate (a2-1) is 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer is −70° C.).

[0141] The content of alkyl (meth)acrylate (a2-1) in the total amount of alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) is preferably 30% by weight to 100% by weight, more preferably 40% by weight to 100% by weight, even more preferably 50% by weight to 100% by weight, and particularly preferably 60% by weight to 100% by weight, in order to further exhibit the effects of the present invention.

[0142] The content of the alkyl (meth)acrylate (a2-1) in the total amount of the monomer component (M2) is preferably 50% by weight to 100% by weight, more preferably 60% by weight to 100% by weight, even more preferably 70% by weight to 100% by weight, and particularly preferably 80% by weight to 100% by weight, in order to further exhibit the effects of the present invention.

[0143] In order to further exert the effects of the present invention, the alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) preferably contains an alkyl (meth)acrylate (a2-2) whose homopolymer has a glass transition temperature Tg in the range of 90° C. to 120° C. (preferably 95° C. to 115° C., more preferably 100° C. to 110° C.). When the alkyl (meth)acrylate (M2) contains the alkyl (meth)acrylate (a2-2), the effects of the present invention can be further exerted.

[0144] An example of the alkyl(meth)acrylate (a2-2) is methyl methacrylate (MMA) (the glass transition temperature Tg of its homopolymer is 105° C.).

[0145] The content of the alkyl (meth)acrylate (a2-2) in the total amount of alkyl (meth)acrylate (a2) that can be contained in the monomer component (M2) is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight, in order to further exhibit the effects of the present invention.

[0146] The content of the alkyl (meth)acrylate (a2-2) in the total amount of the monomer component (M2) is preferably 0 to 40% by weight, more preferably 0 to 30% by weight, even more preferably 0 to 20% by weight, and particularly preferably 0 to 15% by weight, in order to further exhibit the effects of the present invention.

[0147] The content of the polar group-containing monomer (b2) in the monomer component (M2) is preferably 0% by weight to 45% by weight, more preferably 0% by weight to 40% by weight, even more preferably 0% by weight to 35% by weight, and particularly preferably 0% by weight to 30% by weight, in order to further exhibit the effects of the present invention.

[0148] In order to further exert the effects of the present invention, the polar group-containing monomer (b2) preferably includes at least one selected from the group consisting of a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, and more preferably includes both a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group.

[0149] The hydroxyl group-containing monomer (b2-1) may be of one type only, or of two or more types.

[0150] For the hydroxyl group-containing monomer (b2-1), the explanation for the hydroxyl group-containing monomer (b1-1) in the section [A-1-2-1. Acrylic polymer (P1)] can be cited.

[0151] In order to further exert the effects of the present invention, the hydroxyl-containing monomer (b2-1) preferably has a glass transition temperature Tg of its homopolymer of -60°C to -10°C, more preferably -55°C to -10°C, and even more preferably -45°C to -10°C. The glass transition temperature Tg of the homopolymer of the hydroxyl-containing monomer (b2-1) can affect the adhesive properties of the acrylic polymer (P2). The effects of the present invention can be further exerted by using a hydroxyl-containing monomer whose homopolymer has a glass transition temperature Tg within the above range as the hydroxyl-containing monomer (b2-1) that can be contained in the monomer component (M2).

[0152] The glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b2-1) can be determined from the explanation of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [A-1-2-1. Acrylic polymer (P1)].

[0153] In terms of further exerting the effects of the present invention, the hydroxyl group-containing monomer (b2-1) is preferably a hydroxyalkyl(meth)acrylate, more preferably a hydroxyalkyl(meth)acrylate in which the alkyl group moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms, even more preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C) or 4-hydroxybutyl acrylate (4HBA) (glass transition temperature of its homopolymer Tg = -40°C), and particularly preferably 2-hydroxyethyl acrylate (HEA) (glass transition temperature of its homopolymer Tg = -15°C).

[0154] The content of the hydroxyl group-containing monomer (b2-1) in the polar group-containing monomer (b2) is preferably 10% by weight to 100% by weight, more preferably 20% by weight to 100% by weight, even more preferably 30% by weight to 100% by weight, and particularly preferably 40% by weight to 100% by weight, in order to further exhibit the effects of the present invention.

[0155] The content of the hydroxyl group-containing monomer (b2-1) in the monomer component (M2) is preferably 0 to 45% by weight, more preferably 0 to 30% by weight, even more preferably 0 to 25% by weight, and particularly preferably 0 to 20% by weight, in order to further exhibit the effects of the present invention.

[0156] The monomer (b2-2) having a polar group other than a hydroxyl group may be of one type only, or of two or more types.

[0157] For the monomer (b2-2) having a polar group other than a hydroxyl group, the explanation for the monomer (b1-2) having a polar group other than a hydroxyl group in the section [A-1-2-1. Acrylic polymer (P1)] can be cited.

[0158] In order to further exert the effects of the present invention, the glass transition temperature Tg of the homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group is preferably −30° C. to 100° C., more preferably −20° C. to 95° C., and even more preferably −10° C. to 90° C. The glass transition temperature Tg of the homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group can affect the adhesive properties of the acrylic polymer (P2). The effects of the present invention can be further exerted by using, as the monomer (b2-2) having a polar group other than a hydroxyl group that can be contained in the monomer component (M2), a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg within the above range.

[0159] As the monomer (b2-2) having a polar group other than a hydroxyl group, a monomer having a polar group other than a hydroxyl group whose homopolymer has a glass transition temperature Tg of 50° C. to 100° C. is preferred, as it can further exhibit the effects of the present invention. The glass transition temperature Tg of the homopolymer of this monomer is preferably 60° C. to 95° C., and more preferably 70° C. to 90° C.

[0160] With regard to the glass transition temperature Tg of a homopolymer of a monomer (b2-2) having a polar group other than a hydroxyl group, the explanation of the glass transition temperature Tg of a homopolymer of an alkyl (meth)acrylate (a1) that may be contained in the monomer component (M1) in the section [A-1-2-1. Acrylic polymer (P1)] may be cited.

[0161] In order to further enhance the effects of the present invention, the monomer (b2-2) having a polar group other than a hydroxyl group is preferably N-vinyl-2-pyrrolidone (the glass transition temperature Tg of its homopolymer is 80°C).

[0162] The content of the monomer (b2-2) having a polar group other than a hydroxyl group in the polar group-containing monomer (b2) is preferably 0% by weight to 90% by weight, more preferably 10% by weight to 80% by weight, even more preferably 20% by weight to 70% by weight, and particularly preferably 30% by weight to 60% by weight, in order to further exhibit the effects of the present invention.

[0163] The content of the monomer (b2-2) having a polar group other than a hydroxyl group in the monomer component (M2) is preferably 0% by weight to 35% by weight, more preferably 0% by weight to 30% by weight, even more preferably 0% by weight to 25% by weight, and particularly preferably 0% by weight to 20% by weight, in order to further exhibit the effects of the present invention.

[0164] In order to further exert the effects of the present invention, the monomer component (M2) preferably contains an alkyl(meth)acrylate (a2) and at least one selected from the group consisting of a hydroxyl group-containing monomer (b2-1) and a monomer (b2-2) having a polar group other than a hydroxyl group, more preferably contains an alkyl(meth)acrylate (a2), a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group, and further preferably contains a glass homopolymer thereof. The composition includes an alkyl(meth)acrylate (a2-1) having a glass transition temperature Tg in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), an alkyl(meth)acrylate (a2-2) having a glass transition temperature Tg of its homopolymer in the range of -120°C to -90°C (preferably -115°C to -95°C, more preferably -110°C to -100°C), a hydroxyl group-containing monomer (b2-1), and a monomer (b2-2) having a polar group other than a hydroxyl group.

[0165] In order to further exert the effects of the present invention, the total content of the alkyl(meth)acrylate (a2-1) whose homopolymer has a glass transition temperature Tg in the range of -80°C to -60°C (preferably -75°C to -60°C, more preferably -75°C to -65°C), the alkyl(meth)acrylate (a2-2) whose homopolymer has a glass transition temperature Tg in the range of -120°C to -90°C (preferably -115°C to -95°C, more preferably -110°C to -100°C), the hydroxyl group-containing monomer (b2-1), and the monomer having a polar group other than a hydroxyl group (b2-2) in the monomer component (M2) is preferably 60% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, even more preferably 80% by weight to 100% by weight, particularly preferably 90% by weight to 100% by weight, and most preferably 95% by weight to 100% by weight.

[0166] In terms of being able to further exert the effects of the present invention, the monomer component (M1) specifically preferably contains 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, and N-vinyl-2-pyrrolidone.

[0167] The monomer component (M2) may contain another monomer (c2) that does not fall into either the alkyl (meth)acrylate (a2) or the polar group-containing monomer (b2). The other monomer (c2) can be used for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer (P1), adjusting the adhesive properties, etc. The other monomer may be one type or two or more types.

[0168] The content of the other monomer (c2) 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.

[0169] The thermal polymerization initiator can be appropriately selected from any appropriate thermal polymerization initiator depending on the type of polymerization method, and the thermal polymerization initiator may be one type or two or more types.

[0170] Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, and 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride. hydrochloride, azo initiators such as 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (VA-057, Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl) peroxydicarbonate, di Examples of initiators include peroxide initiators such as (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; redox initiators that combine peroxides with reducing agents, such as combinations of persulfates and sodium hydrogen sulfite, and combinations of peroxides and sodium ascorbate; substituted ethane initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0171] The amount of the thermal polymerization initiator used can be set to any appropriate amount as long as the effects of the present invention are not impaired. The amount of the thermal polymerization initiator used is preferably 0.001 to 10 parts by weight, more preferably 0.005 to 5 parts by weight, even more preferably 0.007 to 3 parts by weight, and particularly preferably 0.01 to 1 part by weight, relative to 100 parts by weight of the monomer component (M2), in order to further exhibit the effects of the present invention.

[0172] [A-1-2-3. First embodiment of acrylic adhesive (photocurable acrylic adhesive)] A first embodiment of the acrylic pressure-sensitive adhesive is a photocurable acrylic pressure-sensitive adhesive, which is typically formed by a photocuring reaction of a photocurable acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P1).

[0173] The photocurable acrylic pressure-sensitive adhesive is formed from the photocurable acrylic pressure-sensitive adhesive composition by any appropriate method. A typical example of such a formation method is a method in which the photocurable acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, and then another appropriate substrate is placed on the surface of the pressure-sensitive adhesive layer formed by the application, followed by curing by irradiating with ultraviolet light. The method for applying the photocurable acrylic pressure-sensitive adhesive composition may be any appropriate application method as long as it does not impair the effects of the present invention. Examples of such application methods include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0174] When forming the photocurable acrylic pressure-sensitive adhesive, heating may be performed as necessary. Furthermore, aging may be performed for the purpose of adjusting component migration in the formed photocurable acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and alleviating distortion that may exist in the photocurable acrylic pressure-sensitive adhesive.

[0175] The photocurable acrylic pressure-sensitive adhesive composition may contain an alkyl(meth)acrylate (a1-2). The type of this alkyl(meth)acrylate (a1-2) may be the same as or different from the type of alkyl(meth)acrylate (a1-2) that can be used to produce the acrylic polymer (P1).

[0176] The content of the alkyl(meth)acrylate (a1-2) in the photocurable acrylic pressure-sensitive adhesive composition is preferably 20 to 90% by weight, more preferably 30 to 80% by weight, even more preferably 40 to 70% by weight, and particularly preferably 50 to 65% by weight, relative to the total amount (100% by weight) of the acrylic polymer (P1), in order to further exhibit the effects of the present invention.

[0177] The photocurable acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L1). The crosslinking agent (L1) may be one kind or two or more kinds.

[0178] The content of the crosslinking agent (L1) in the photocurable acrylic pressure-sensitive adhesive composition can be set to any appropriate content as long as the effects of the present invention are not impaired. The content of the crosslinking agent (L1) in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.001 to 0.5 parts by weight, more preferably 0.005 to 0.3 parts by weight, even more preferably 0.01 to 0.2 parts by weight, and particularly preferably 0.05 to 0.1 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1), in order to further exhibit the effects of the present invention.

[0179] As the crosslinking agent (L1), any appropriate crosslinking agent can be used as long as it does not impair the effects of the present invention. As such a crosslinking agent (L1), preferably, a polyfunctional (meth)acrylate is used.

[0180] As the polyfunctional (meth)acrylate, any appropriate polyfunctional (meth)acrylate can be used as long as it does not impair the effects of the present invention. The polyfunctional (meth)acrylate may be one type only or two or more types. Specific examples of such polyfunctional (meth)acrylates include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6- Examples of the ester compound include ester compounds of polyhydric alcohols and (meth)acrylic acid, such as hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and tetramethylolmethane tri(meth)acrylate; allyl (meth)acrylate; vinyl (meth)acrylate; divinylbenzene; epoxy acrylate; polyester acrylate; urethane acrylate; butyl di(meth)acrylate; and hexyl di(meth)acrylate.

[0181] The photocurable acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer may be of one type only, or of two or more types.

[0182] The content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition can be set to any appropriate content as long as the effects of the present invention are not impaired. In order to further exhibit the effects of the present invention, the content of the acrylic oligomer in the photocurable acrylic pressure-sensitive adhesive composition is preferably 0.1 to 20 parts by weight, more preferably 1 to 15 parts by weight, even more preferably 3 to 10 parts by weight, and particularly preferably 5 to 8 parts by weight, relative to 100 parts by weight of the acrylic polymer (P1).

[0183] The weight average molecular weight of the acrylic oligomer is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, still more preferably 1,500 to 10,000, and particularly preferably 2,000 to 8,000. When the photocurable acrylic pressure-sensitive adhesive composition contains an acrylic oligomer, the effects of the present invention can be more effectively exhibited.

[0184] The weight-average molecular weight (Mw) can be determined in terms of polystyrene by the GPC method. For example, it can be measured under the following conditions using a high-speed GPC device "HPLC-8120GPC" manufactured by Tosoh Corporation. Column: TSKgel SuperHZM-H / HZ4000 / HZ3000 / HZ2000 Solvent: tetrahydrofuran Flow rate: 0.6ml / min

[0185] The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C to 300°C, more preferably 30°C to 300°C, and even more preferably 40°C to 300°C.

[0186] The Tg of an acrylic oligomer refers to the value calculated from the Fox formula based on the Tg of the homopolymer of each monomer constituting the acrylic oligomer and the weight fraction (copolymerization ratio by weight) of the monomer. The Fox formula and the Tg of various homopolymers can be found in the explanation in the section [A-1-2-1. Acrylic Polymer (P1)].

[0187] The acrylic oligomer is preferably an acrylic oligomer obtained from a monomer composition containing, as an essential component, a (meth)acrylic acid ester having a cyclic structure in the molecule, and more preferably an acrylic oligomer obtained from a monomer composition containing, as essential components, a (meth)acrylic acid ester having a cyclic structure in the molecule and a (meth)acrylic acid alkyl ester having a linear or branched alkyl group.

[0188] The (meth)acrylic acid ester having a cyclic structure in the molecule may be of one type only, or of two or more types.

[0189] The (meth)acrylic acid alkyl ester having a linear or branched alkyl group may be of one type only, or of two or more types.

[0190] The cyclic structure in the (meth)acrylic acid ester having a cyclic structure in the molecule may be either an aromatic ring or a non-aromatic ring.

[0191] Examples of aromatic rings include aromatic carbocycles (for example, monocyclic carbocycles such as a benzene ring, and fused carbocycles such as a naphthalene ring), and various aromatic heterocycles.

[0192] Examples of non-aromatic rings include non-aromatic aliphatic rings (non-aromatic alicyclic rings) (e.g., cycloalkane rings such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; cycloalkene rings such as cyclohexene), non-aromatic bridged rings (e.g., bicyclic hydrocarbon rings such as pinane, pinene, bornane, norbornane, and norbornene; tricyclic or higher aliphatic hydrocarbon rings (bridged hydrocarbon rings) such as adamantane), and non-aromatic heterocycles (e.g., epoxy rings, oxolane rings, and oxetane rings). Examples of tricyclic or higher aliphatic hydrocarbon rings (tricyclic or higher bridged hydrocarbon rings) include dicyclopentanyl, dicyclopentenyl, adamantyl, tricyclopentanyl, and tricyclopentenyl groups.

[0193] Specific examples of the (meth)acrylic acid ester having a cyclic structure in the molecule include (meth)acrylic acid cycloalkyl esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1- Examples include (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings, such as adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate; (meth)acrylic acid esters having an aromatic ring, such as (meth)acrylic acid aryl esters, such as phenyl (meth)acrylate; (meth)acrylic acid aryloxyalkyl esters, such as phenoxyethyl (meth)acrylate; and (meth)acrylic acid arylalkyl esters, such as benzyl (meth)acrylate.

[0194] As the (meth)acrylic acid ester having a cyclic structure in the molecule, a non-aromatic ring-containing (meth)acrylic acid ester is preferred, in terms of being able to further exhibit the effects of the present invention, more preferred are cyclohexyl acrylate (CHA), cyclohexyl methacrylate (CHMA), dicyclopentanyl acrylate (DCPA), and dicyclopentanyl methacrylate (DCPMA), and even more preferred are dicyclopentanyl acrylate (DCPA) and dicyclopentanyl methacrylate (DCPMA).

[0195] The content of the (meth)acrylic acid ester having a cyclic structure in the molecule of all the monomers that can be used to constitute the acrylic oligomer is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, relative to 100 parts by weight of all the monomers, in order to further exhibit the effects of the present invention.

[0196] Examples of (meth)acrylic acid alkyl esters having a linear or branched alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and methyl (meth)acrylate. Examples of suitable (meth)acrylic acid alkyl esters include those in which the alkyl group has 1 to 20 carbon atoms, such as isooctyl, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, methyl methacrylate (MMA) is preferred in that it can further exert the effects of the present invention.

[0197] The content of the (meth)acrylic acid alkyl ester having a linear or branched alkyl group in all monomers that can be used to constitute the acrylic oligomer is preferably 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, and even more preferably 20 to 60 parts by weight, relative to 100 parts by weight of all monomers, in order to further exhibit the effects of the present invention.

[0198] The total monomers (monomer composition) that can be used to form the acrylic oligomer may contain, in addition to the (meth)acrylic acid ester having a cyclic structure in the molecule and the (meth)acrylic acid alkyl ester having a linear or branched alkyl group, other monomers (copolymerizable monomers) that can be copolymerized with these monomers. The content of the other monomers (copolymerizable monomers) in the total monomers (monomer composition) that can be used to form the acrylic oligomer is preferably less than 50 parts by weight, more preferably 40 parts by weight or less, even more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less, relative to 100 parts by weight of the total monomers.

[0199] Examples of such other monomers (copolymerizable monomers) include (meth)acrylic acid alkoxyalkyl esters (e.g., 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-ethoxybutyl (meth)acrylate, etc.), carboxyl group-containing monomers (e.g., acid anhydride group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, maleic anhydride, etc.), hydroxyl group-containing monomers (e.g., hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc.); vinyl alcohol; allyl alcohol; etc.), amide group-containing monomers (e.g., (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, etc.), amino group-containing monomers (e.g., aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, etc.), cyano group-containing monomers (e.g., acrylonitrile, methacrylonitrile, etc.), sulfonic acid group-containing monomers (e.g., sodium vinyl sulfonate, etc.), phosphoric acid group-containing monomers (e.g., 2-hydroxyethyl acryloyl phosphate, etc.), isocyanate group-containing monomers (e.g., 2-methacryloyloxyethyl isocyanate, etc.), imide group-containing monomers (e.g., cyclohexylmaleimide, isopropylmaleimide, etc.).

[0200] The total monomers (monomer composition) that can be used to form the acrylic oligomer particularly preferably contain (1) at least one monomer selected from dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate, and cyclohexyl methacrylate, and (2) methyl methacrylate. In this case, the content of the monomer (1) is preferably 30 to 70 parts by weight, and the content of the monomer (2) is preferably 30 to 70 parts by weight, relative to 100 parts by weight of the total monomers (monomer composition) that can be used to form the acrylic oligomer.

[0201] The acrylic oligomer can be produced by any suitable polymerization method as long as the effects of the present invention are not impaired. Examples of such polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). Among these, bulk polymerization and solution polymerization are preferred, and solution polymerization is more preferred.

[0202] Examples of solvents that can be used in the polymerization include organic solvents such as esters such as ethyl acetate and n-butyl acetate, aromatic hydrocarbons such as toluene and benzene, aliphatic hydrocarbons such as n-hexane and n-heptane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and ketones such as methyl ethyl ketone and methyl isobutyl ketone. Only one type of solvent may be used, or two or more types may be used.

[0203] In the polymerization, any appropriate polymerization initiator (for example, a thermal polymerization initiator or a photopolymerization initiator) can be used as long as it does not impair the effects of the present invention. The polymerization initiator may be one type or two or more types. When solution polymerization is performed, it is preferable to use an oil-soluble polymerization initiator.

[0204] As the thermal polymerization initiator, any appropriate thermal polymerization initiator can be used as long as it does not impair the effects of the present invention. The thermal polymerization initiator may be one type or two or more types. For specific examples of such thermal polymerization initiators, the explanation of the thermal polymerization initiator in the section [A-1-2-2. Acrylic polymer (P2)] can be used.

[0205] The content of the thermal polymerization initiator is, for example, preferably 0.1 to 15 parts by weight relative to 100 parts by weight of all the monomers (monomer composition) that can be used to form the acrylic oligomer.

[0206] As the photopolymerization initiator, any appropriate photopolymerization initiator can be used as long as it does not impair the effects of the present invention. The photopolymerization initiator may be one type or two or more types. For specific examples of such photopolymerization initiators, the explanation of the photopolymerization initiator in the section [A-1-2-1. Acrylic polymer (P1)] can be cited.

[0207] The content of the photopolymerization initiator is preferably 0.001 to 0.5 parts by weight, for example, relative to 100 parts by weight of all monomers (monomer composition) that can be used to form the acrylic oligomer.

[0208] During polymerization of the acrylic oligomer, a chain transfer agent may be used to adjust the molecular weight (preferably to adjust the weight average molecular weight to 1,000 to 30,000). Examples of the chain transfer agent include 2-mercaptoethanol, α-thioglycerol, 2,3-dimercapto-1-propanol, octyl mercaptan, t-nonyl mercaptan, dodecyl mercaptan (lauryl mercaptan), t-dodecyl mercaptan, glycidyl mercaptan, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycolic acid esters of ethylene glycol, thioglycolic acid esters of neopentyl glycol, thioglycolic acid esters of pentaerythritol, and α-methylstyrene dimer. Among these, from the viewpoint of suppressing whitening of the double-sided pressure-sensitive adhesive tape of the present invention, α-thioglycerol and methyl thioglycolate are preferred, and α-thioglycerol is particularly preferred. Only one type of chain transfer agent may be used, or two or more types may be used.

[0209] The content of the chain transfer agent is, for example, preferably 0.1 to 20 parts by weight, more preferably 0.2 to 15 parts by weight, and even more preferably 0.3 to 10 parts by weight, relative to 100 parts by weight of all monomers (monomer composition) that can be used to constitute the acrylic oligomer.

[0210] The photocurable acrylic pressure-sensitive adhesive composition may contain any appropriate other components within the scope of not impairing the effects of the present invention, such as a tackifier, an inorganic filler, an organic filler, a metal powder, a pigment, a colorant, a foil-like material, a softener, an antioxidant, a conductive agent, an ultraviolet absorber, an antioxidant, a light stabilizer, a surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, another crosslinking agent, a solvent, a catalyst, a crosslinking catalyst, and a crosslinking retarder.

[0211] [A-1-2-4. Second embodiment of acrylic adhesive (thermosetting acrylic adhesive)] A second embodiment of the acrylic pressure-sensitive adhesive is a thermosetting acrylic pressure-sensitive adhesive, which is typically formed by a crosslinking reaction of a thermosetting acrylic pressure-sensitive adhesive composition containing an acrylic polymer (P2).

[0212] The thermosetting acrylic pressure-sensitive adhesive is formed from the thermosetting acrylic pressure-sensitive adhesive composition by any appropriate method. A typical example of such a formation method is a method in which the thermosetting acrylic pressure-sensitive adhesive composition is applied to any appropriate substrate, heated and dried as necessary, and cured as necessary to form a sheet of the thermosetting acrylic pressure-sensitive adhesive on the substrate. Any coating method can be used as long as it does not impair the effects of the present invention. Examples of such coating methods include roll coating, gravure roll coating, reverse roll coating, kiss roll coating, dip roll coating, bar coating, roll brush coating, spray coating, knife coating, air knife coating, comma coating, direct coating, and die coating.

[0213] Any appropriate means may be used to heat and dry the thermosetting acrylic pressure-sensitive adhesive composition as long as the effects of the present invention are not impaired. Examples of such heating and drying means include heating to approximately 60°C to 180°C. Any appropriate means may be used to cure the acrylic pressure-sensitive adhesive composition as long as the effects of the present invention are not impaired. Examples of such curing means include ultraviolet irradiation, laser irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, and electron beam irradiation.

[0214] When forming the thermosetting acrylic pressure-sensitive adhesive, aging may be carried out as necessary for the purpose of adjusting component migration in the formed thermosetting acrylic pressure-sensitive adhesive, promoting the crosslinking reaction, and alleviating distortion that may exist in the photocurable acrylic pressure-sensitive adhesive.

[0215] The thermosetting acrylic pressure-sensitive adhesive composition preferably contains a crosslinking agent (L2). The crosslinking agent (L2) may be one kind or two or more kinds.

[0216] The use of the crosslinking agent (L2) can impart appropriate cohesive strength to the thermosetting acrylic pressure-sensitive adhesive. The crosslinking agent (L2) can be contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction, a form before crosslinking reaction, a partially crosslinked form, or an intermediate or composite form thereof. The crosslinking agent (L2) is typically contained in the thermosetting acrylic pressure-sensitive adhesive in a form after crosslinking reaction.

[0217] The content of the crosslinking agent (L2) in the thermosetting acrylic pressure-sensitive adhesive composition is preferably 0.005 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, even more preferably 0.01 to 3 parts by weight, still more preferably 0.01 to 2 parts by weight, particularly preferably 0.01 to 1.5 parts by weight, and most preferably 0.01 to 1.3 parts by weight, relative to 100 parts by weight of the acrylic polymer (P2), in order to further exhibit the effects of the present invention.

[0218] Examples of the crosslinking agent include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, a silane-based crosslinking agent, an alkyl etherified melamine-based crosslinking agent, a metal chelate-based crosslinking agent, and a peroxide. In terms of being able to further exhibit the effects of the present invention, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, or a peroxide is preferred, and an isocyanate-based crosslinking agent or a peroxide is more preferred.

[0219] The isocyanate crosslinking agent can be a compound having two or more isocyanate groups (including isocyanate-regenerating polar groups in which the isocyanate group is temporarily protected by a blocking agent or oligomerization) per molecule. Examples of the isocyanate crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

[0220] Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate; trimethylolpropane / tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL), and isocyanurate of hexamethylene diisocyanate (e.g., manufactured by Tosoh Corporation, trade name: Coronate HL). Examples of suitable polyisocyanates include isocyanate adducts such as those manufactured by Mitsui Chemicals under the trade name of Coronate HX; trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D110N), trimethylolpropane adducts of xylylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D120N), trimethylolpropane adducts of isophorone diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D140N), and trimethylolpropane adducts of hexamethylene diisocyanate (for example, Mitsui Chemicals, Inc., trade name: Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols; and polyisocyanates multifunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc. Among these, aromatic isocyanates and alicyclic isocyanates are preferred because they can achieve a good balance between deformability and cohesive strength.

[0221] As the epoxy-based crosslinking agent, a multifunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy-based crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether. Examples of epoxy crosslinking agents include glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Commercially available epoxy crosslinking agents include, for example, "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc.

[0222] Examples of peroxides include dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, di-t-butylperoxy-3,3,5-trimethylcyclohexane, t-butyl hydroperoxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxin)hexyne-3, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(t-butylperoxy)hexane, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy Neodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, 1,1-di(t-butylperoxy)cyclohexane, t-butylperoxy-2-ethylhexyl carbonate, t-amylperoxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-hexanoate, t-butyl peroxypivalate, and t-hexyl peroxypivalate. Commercially available peroxides include, for example, the "Niper BMT" series and "Niper BW" series manufactured by Nippon Oil & Fats Corporation.

[0223] The thermosetting acrylic pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer may be of one type or two or more types. For the acrylic oligomer, the explanation in the section [A-1-2-3. First embodiment of acrylic pressure-sensitive adhesive (photocurable acrylic pressure-sensitive adhesive)] may be used.

[0224] The thermosetting acrylic adhesive composition may contain any suitable other components as long as the effects of the present invention are not impaired. Such other components include, for example, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, colorants, foils, softeners, anti-aging agents, conductive agents, ultraviolet absorbers, antioxidants, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, other crosslinking agents, solvents, catalysts, crosslinking catalysts, crosslinking retardants.

[0225] <A-1-3. Antistatic layer> In addition to the base material layer and the adhesive layer, the adhesive film may have an antistatic layer. The antistatic layer can be provided, for example, on the side opposite to the adhesive layer of the base material layer, between the base material layer and the adhesive layer, on the side opposite to the base material layer of the adhesive layer, etc.

[0226] As the thickness of the antistatic layer, any appropriate thickness can be adopted as long as the effects of the present invention are not impaired. Such a thickness is preferably 1 nm to 1000 nm, more preferably 5 nm to 900 nm, still more preferably 7.5 nm to 800 nm, and particularly preferably 10 nm to 700 nm.

[0227] The antistatic layer may be only one layer or two or more layers.

[0228] As the antistatic layer, any appropriate antistatic layer can be adopted as long as it can exhibit an antistatic effect and the effects of the present invention are not impaired. Such an antistatic layer is preferably an antistatic layer formed by coating a conductive coating liquid containing a conductive polymer on any appropriate base material layer. Specifically, for example, it is an antistatic layer formed by coating a conductive coating liquid containing a conductive polymer on a resin base film. Specific coating methods include roll coating method, bar coating method, gravure coating method, etc.

[0229] Any suitable conductive polymer may be used as the conductive polymer as long as it does not impair the effects of the present invention. Examples of such conductive polymers include conductive polymers in which a π-conjugated conductive polymer is doped with a polyanion. Examples of π-conjugated conductive polymers include chain-like conductive polymers such as polythiophene, polypyrrole, polyaniline, and polyacetylene. Examples of polyanions include polystyrene sulfonic acid, polyisoprene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, polyacrylate ethyl sulfonic acid, and polymethacrylic carboxylic acid. Only one type of conductive polymer may be used, or two or more types may be used.

[0230] <A-2. Release liner> The thickness of the release liner is preferably 1 μm to 300 μm, more preferably 10 μm to 200 μm, even more preferably 20 μm to 150 μm, particularly preferably 35 μm to 100 μm, and most preferably 50 μm to 80 μm, in order to better exhibit the effects of the present invention.

[0231] The release liner typically comprises a resin substrate film.

[0232] Examples of the resin substrate film include plastic films made of polyester-based resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); plastic films made of olefin-based resins containing α-olefin as a monomer component, such as polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA); plastic films made of polyvinyl chloride (PVC); plastic films made of vinyl acetate-based resins; plastic films made of polycarbonate (PC); and plastic films made of polyphenylene sulfide (PPS). plastic films made of amide-based resins such as polyamide (nylon) and wholly aromatic polyamide (aramid); plastic films made of polyimide-based resins; plastic films made of polyether ether ketone (PEEK); plastic films made of olefin-based resins such as polyethylene (PE) and polypropylene (PP); and plastic films made of fluorine-based resins such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and chlorofluoroethylene-vinylidene fluoride copolymer.

[0233] The resin substrate film may be composed of only one layer, or may be composed of two or more layers. The resin substrate film may be a stretched film.

[0234] The resin substrate film may be subjected to a surface treatment, such as corona treatment, plasma treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, ionizing radiation treatment, or coating with a primer.

[0235] The resin substrate film may contain any appropriate additives as long as the effects of the present invention are not impaired.

[0236] The release liner may have a release layer. When the release liner has a release layer, typically the release layer side is laminated directly onto the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film.

[0237] Any suitable material can be used for forming the release layer as long as it does not impair the effects of the present invention. Examples of such materials include silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, and fatty acid amide-based release agents. Among these, silicone-based release agents are preferred. The release layer can be formed as a coating layer.

[0238] The thickness of the release layer may be any appropriate thickness depending on the purpose, as long as it does not impair the effects of the present invention. Such a thickness is preferably 10 nm to 2000 nm, more preferably 10 nm to 1500 nm, even more preferably 10 nm to 1000 nm, and particularly preferably 10 nm to 500 nm.

[0239] The release layer may be a single layer or two or more layers.

[0240] Examples of silicone-based release layers include addition reaction type silicone resins. Specific examples of addition reaction type silicone resins include KS-774, KS-775, KS-778, KS-779H, KS-847H, and KS-847T manufactured by Shin-Etsu Chemical Co., Ltd.; TPR-6700, TPR-6710, and TPR-6721 manufactured by Toshiba Silicones; and SD7220 and SD7226 manufactured by Toray Dow Corning. The coating amount (after drying) of the silicone-based release layer is preferably 0.01 g / m. 2 ~2g / m 2 and more preferably 0.01 g / m 2 ~1g / m 2 and more preferably 0.01 g / m 2 ~0.5g / m 2 is.

[0241] The release layer can be formed, for example, by applying the above-mentioned forming material onto any appropriate layer by a conventionally known coating method such as reverse gravure coating, bar coating, die coating, etc., and then usually curing it by heat treatment at about 120 to 200 °C. Further, heat treatment and irradiation with active energy rays such as ultraviolet irradiation may be used in combination as necessary.

[0242] The release liner may have an antistatic layer.

[0243] Regarding the antistatic layer, the description in the section <A-1-3. Antistatic layer> can be incorporated.

[0244] One embodiment of the release liner includes a resin base film and a release layer in this order. Typically, this embodiment consists of a resin base film and a release layer.

[0245] Another embodiment of the release liner includes a resin base film, an antistatic layer, and a release layer in this order. Typically, this embodiment consists of a resin base film, an antistatic layer, and a release layer.

[0246] Still another embodiment of the release liner includes an antistatic layer, a resin base film, an antistatic layer, and a release layer in this order. Typically, this embodiment consists of an antistatic layer, a resin base film, an antistatic layer, and a release layer.

[0247] ≪A-3. Protective Film≫ As the protective film, any appropriate protective film can be adopted as long as the effects of the present invention are not impaired. Such a protective film is typically a protective film having an adhesive layer on at least one side of a base film, and a protective film known as an optical surface protective film can be preferably adopted.

[0248] On the surface of the adhesive layer of the protective film, a release liner may be provided as necessary. Regarding the release liner, the description in the section ≪A-2 Release Liner≫ can be incorporated.

[0249] The thickness of the substrate film is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, even more preferably 10 μm to 100 μm, particularly preferably 15 μm to 80 μm, and most preferably 20 μm to 60 μm. When the thickness of the substrate film is within the above range, the effects of the present invention can be more effectively exhibited.

[0250] The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 250 μm, more preferably 2 μm to 150 μm, even more preferably 3 μm to 100 μm, particularly preferably 5 μm to 50 μm, and most preferably 7 μm to 30 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, the effects of the present invention can be more effectively exhibited.

[0251] As the substrate film and pressure-sensitive adhesive layer, a substrate film and pressure-sensitive adhesive layer that can be used in a protective film known as an optical surface protection film can be preferably used, and for example, the description of the substrate film and pressure-sensitive adhesive layer described in JP 2018-109092 A can be used.

[0252] <<B. Manufacturing of reinforcing film>> The reinforcing film according to the embodiment of the present invention can be produced by any appropriate method as long as the effects of the present invention are not impaired.

[0253] As a representative example of a method for manufacturing a reinforcing film according to an embodiment of the present invention, we will explain a case where the reinforcing film according to an embodiment of the present invention has a release liner, two adhesive films, and a protective film in that order, and the two adhesive films, adhesive film (I) and adhesive film (II), are arranged so as to have a gap between them.

[0254] In one embodiment of the method for producing a reinforcing film according to the present invention, a laminate (X) having two adhesive films on one release liner and a protective film are separately produced, and then the surface of the base material layer of the laminate (X) and the surface of the adhesive layer of the protective film are attached to one protective film.

[0255] The laminate (X) can be produced, for example, by applying a pressure-sensitive adhesive composition (typically an acrylic pressure-sensitive adhesive composition) that forms the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the pressure-sensitive adhesive film onto a substrate layer, and optionally heating and drying the composition and optionally curing the composition to form the pressure-sensitive adhesive layer on the substrate layer. The laminate (X) can be produced by adhering one release liner (on the release layer side, if any) to the surface of the pressure-sensitive adhesive layer (I), (II) of each of the two pressure-sensitive adhesive films (I) and (II) obtained in this manner, opposite the substrate layers (I), (II), so that the two pressure-sensitive adhesive films (I), (II) are arranged with a gap between them.

[0256] The protective film is produced, for example, by applying a pressure-sensitive adhesive composition that forms the pressure-sensitive adhesive that constitutes the pressure-sensitive adhesive layer onto a base film, heating and drying as necessary, and curing as necessary to form the pressure-sensitive adhesive layer on the base film.

[0257] Until the laminate (X) and the protective film are attached, any appropriate release liner may be attached to protect the exposed surface of the pressure-sensitive adhesive layer of the protective film.

[0258] <<C. Uses of reinforcing film>> The reinforced film according to the embodiment of the present invention can be used for any suitable application. For example, the reinforced film according to the embodiment of the present invention is preferably used for reinforcing optical components and electronic components. Examples of optical components include LCDs, touch panels using LCDs, color filters used in LCDs, polarizing plates, and the like.

[0259] The optical and electronic components may be flexible devices such as bendable devices (devices that can be bent) having movable bending parts, foldable devices (devices that can be folded), or rollable devices (devices that can be rolled up). [Example]

[0260] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0261] <Measurement of flexion recovery angle> The release liner was peeled off from the prepared adhesive film with release liner, attached to a polyimide film (UPILEX25RN, manufactured by Ube Industries), and cut to TD 80 mm x MD 25 mm. The cut sample was wrapped around a 3 mm thick glass sheet made by stacking two 1.5 mm thick glass sheets, with the polyimide film side facing outward. When wrapping, the glass and the sample were secured in place with tape to prevent any gaps between them. The prepared sample was stored at 85°C for 48 hours, then removed from the glass, and the sample's flex recovery angle was measured using a protractor.

[0262] <Measurement of light transmittance at 550 nm> The prepared PSA film with release liner was cut to TD 20mm x MD 50mm. The release liner was peeled off from the cut PSA film with release liner, and the transmittance was measured using a Hitachi High-Technologies Corporation U4100 spectrophotometer. The measurement condition was transmittance at 550nm.

[0263] <Measurement of storage modulus G'> The storage modulus G' corresponds to the portion of the material that is stored as elastic energy when the material is deformed, and is an index that indicates the degree of hardness. Only the adhesive layer of the adhesive film was taken out, laminated to a thickness of about 1 mm, and punched out to a diameter of 8 mm to prepare a cylindrical pellet, which was used as a measurement sample. Using a dynamic viscoelasticity measuring device (TA Instruments, DHR), the obtained measurement sample was fixed to a φ8 mm parallel plate jig, and the storage modulus G' was calculated. The measurement conditions were as follows: Measurement: Shear mode Temperature range: -60℃~200℃ Heating rate: 5°C / min Frequency: 1Hz

[0264] <Measurement of adhesive strength to glass> The prepared PSA film with release liner was cut to a dimension of 25 mm TD x 100 mm MD. The release liner was peeled off from the cut PSA film with release liner, and the film was attached to glass (S2004U8, manufactured by Matsunami Glass) using a 2 kg roller back and forth once. The obtained evaluation sample was stored at room temperature for 30 minutes and then measured using a tensile tester. The tensile tester used was an "Autograph AG-Xplus HS 6000 mm / min High-Speed ​​Model (AG-50NX plus)" manufactured by Shimadzu Corporation. After placing the evaluation sample in the tensile tester, the tensile test was initiated. The conditions for the tensile test were a peel angle of 180 degrees and a peel speed (pulling speed): 300 mm / min. The load when peeling the PSA film from the glass was measured, and the average load at that time was taken as the adhesive strength.

[0265] <Measurement of release force (A) of release liner> The prepared PSA film with release liner was cut into a TD 50 mm x MD 100 mm sample. Double-sided tape No. 31B (manufactured by Nitto Denko) was applied to glass, and the substrate layer surface of the resulting sample was bonded to the glass to form an evaluation sample. The peel strength of the release liner was measured using a tensile tester. The tensile tester used was an Autograph AG-Xplus HS 6000 mm / min High-Speed ​​Model (AG-50NX plus) manufactured by Shimadzu Corporation. After placing the evaluation sample in the tensile tester, the tensile test began. The test conditions were a peel angle of 180° and a peel speed (pulling rate) of 300 mm / min. The load applied when peeling the release liner from the PSA film was measured, and the average load was recorded as the release strength (A) of the release liner. The values ​​listed in the table are values ​​converted to measurements per 25 mm width.

[0266] <Measurement of protective film peel strength (B)> The prepared protective film was cut to a dimension of 25 mm TD x 100 mm MD. The release liner was peeled off from the prepared adhesive film with release liner and attached to glass (S2004U8, manufactured by Matsunami Glass). The release liner was peeled off from the protective film and attached to the base layer surface of the adhesive film using a 2 kg roller once back and forth. This was used as an evaluation sample. After storing at room temperature for 30 minutes, the peel strength of the protective film was measured using a tensile tester. The tensile tester used was an "Autograph AG-Xplus HS 6000 mm / min High-Speed ​​Model (AG-50NX plus)" manufactured by Shimadzu Corporation. After placing the evaluation sample in the tensile tester, the tensile test was initiated. The conditions for the tensile test were a peel angle of 180 degrees and a peel speed (pulling rate) of 300 mm / min. The load when the protective film was peeled from the adhesive film was measured, and the average load at that time was defined as the peel strength (B) of the protective film.

[0267] [Production Example 1]: Production of adhesive layer (1) <Production of acrylic pressure-sensitive adhesive composition (1)> Monomer components: 2-ethylhexyl acrylate (2EHA): 63 parts by weight, N-vinyl-2-pyrrolidone (NVP): 15 parts by weight, methyl methacrylate (MMA): 9 parts by weight, 2-hydroxyethyl acrylate (HEA): 13 parts by weight, 2,2'-azobisisobutyronitrile (polymerization initiator): 0.2 parts by weight, and ethyl acetate (polymerization solvent): 133 parts by weight were added to a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, the temperature was raised to 65°C and reacted for 5 hours, then raised to 70°C and reacted for 2 hours, and ethyl acetate was added to obtain a solution of acrylic polymer (1) with a solids concentration of 30% by weight. The weight-average molecular weight of the acrylic polymer (1) was 800,000. Next, an isocyanate-based crosslinking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals, Inc.) was added to the solution of acrylic polymer (1) so that the amount was 1.1 parts by weight in terms of solid content per 100 parts by weight of acrylic polymer (1) (solid content), and the mixture was mixed to produce an acrylic pressure-sensitive adhesive composition (1). <Production of Pressure-Sensitive Adhesive Layer (1)> A 50 μm thick polyethylene terephthalate (PET) film ("MRV50T100J" manufactured by Mitsubishi Chemical) with a silicone release layer on its surface was used as a release liner (1a) (dual release film), and the above-mentioned acrylic pressure-sensitive adhesive composition (1) was applied to the release liner (1a) to a thickness of 13 μm to form a coating layer. Next, the release liner (1a) with the coating layer formed thereon was placed in an oven, and the coating layer was dried at 130 ° C. for 1 minute. After that, a 50 μm thick polyethylene terephthalate (PET) film ("MRQ50T100J" manufactured by Mitsubishi Chemical) with a silicone release layer on its surface was used as a release liner (1b) to protect the surface of the coating layer, and a 13 μm thick pressure-sensitive adhesive layer (1) was produced as a laminate (1) of release liner (1a) / pressure-sensitive adhesive layer (1) / release liner (1b). The properties of the pressure-sensitive adhesive layer (1) are shown in Table 1.

[0268] [Production Example 2]: Production of adhesive layer (2) <Production of Prepolymer Composition (2)> As monomer components for forming a prepolymer, 60 parts by weight of lauryl acrylate (LA), 22 parts by weight of 2-ethylhexyl acrylate (2EHA), 8 parts by weight of 4-hydroxybutyl acrylate (4HBA), and 10 parts by weight of N-vinyl-2-pyrrolidone (NVP) were blended, and as photopolymerization initiators, 0.01 parts by weight of BASF's "Irgacure 184" and 0.01 parts by weight of BASF's "Irgacure 651" were blended, and polymerization was carried out by irradiation with ultraviolet light to obtain prepolymer composition (2) (polymerization rate: approximately 10%). <Production of acrylic oligomer> 60 parts by weight of dicyclopentanyl methacrylate (DCPMA) and 40 parts by weight of methyl methacrylate (MMA) as monomer components, 3.4 parts by weight of α-thioglycerol as a chain transfer agent, and ethyl acetate as a polymerization solvent to a concentration of 60% were mixed and stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was added as a thermal polymerization initiator and reacted at 70°C for 2 hours. Then, 0.1 parts of AIBN was added, and the mixture was heated to 80°C and reacted for 2 hours to obtain an acrylic oligomer solution. The acrylic oligomer solution was then dried at 85°C to obtain an acrylic oligomer powder. The weight-average molecular weight of the acrylic oligomer was 5100 and the glass transition temperature (Tg) was 130°C. <Production of acrylic pressure-sensitive adhesive composition (2)> To 100 parts by weight of the above prepolymer composition (2), 37 parts by weight of 2-ethylhexyl acrylate (2EHA), 0.08 parts by weight of 1,6-hexanediol diacrylate (HDDA), 6 parts by weight of the above acrylic oligomer, and 0.3 parts by weight of a silane coupling agent ("KBM403" manufactured by Shin-Etsu Chemical Co., Ltd.) were added as post-added components, and then these were mixed uniformly to produce an acrylic pressure-sensitive adhesive composition (2). <Production of Pressure-Sensitive Adhesive Layer (2)> A 75 μm thick polyethylene terephthalate (PET) film ("Diafoil MRF75" manufactured by Mitsubishi Chemical) with a silicone release layer on its surface was used as a release liner (2a) (double-duty release film), and the above-mentioned acrylic pressure-sensitive adhesive composition (2) was applied to the release liner (2a) to a thickness of 15 μm to form a coating layer. Onto the formed coating layer, a 75 μm thick PET film ("Diafoil MRE75" manufactured by Mitsubishi Chemical) with one side treated with silicone release was attached as a cover sheet (double-duty release film) and used as a release liner (2b). The obtained laminate was then exposed from the cover sheet side to a lamp with an irradiation intensity of 5 mW / cm on the irradiated surface. 2The adhesive layer (2) was photocured by irradiating it with ultraviolet light using a black light whose position was adjusted so that the adhesive layer (2) was 15 μm thick, to produce a laminate (2) of release liner (2a) / adhesive layer (2) / release liner (2b). The properties of the pressure-sensitive adhesive layer (2) are shown in Table 1.

[0269] [Table 1]

[0270] [Manufacturing Example 3] (Production of adhesive film (1)) A 25% aqueous solution of polyester resin (Toyobo Co., Ltd., trade name "Vylonal MD-1480") was used as the binder, and 100 parts by weight of solids, along with 20 parts by weight of conductive polymer and 5 parts by weight of melamine-based crosslinker (Sumitomo Chemical Co., Ltd., trade name "Sumimar M-50W"), was added to a water / ethanol (1 / 1 (by weight)) mixed solvent and stirred for approximately 20 minutes to thoroughly mix. In this way, a coating material (X) with a solids content of approximately 0.4% was prepared. The conductive polymer used was an aqueous solution (Bytron P, H.C. Stark) containing 0.5% poly(3,4-ethylenedioxythiophene) (PEDOT) and 0.8% polystyrene sulfonate (weight-average molecular weight 150,000) (PSS). The coating material (X) was applied with a bar coater to one side of a 50 μm-thick polyimide (PI) substrate ("UPI50RN" manufactured by Ube Industries, Ltd.) serving as a substrate layer, and the coating material (X) was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (1) obtained by peeling off the release liner (1b) from the laminate (1) obtained in Production Example 1 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (1) with a release liner (1a).

[0271] [Manufacturing Example 4] (Production of adhesive film (2)) The coating material (X) prepared in Production Example 3 was applied to one side of a 50 μm-thick polyimide (PI) substrate ("UPI50RN" manufactured by Ube Industries, Ltd.) serving as a substrate layer using a bar coater, and the coating material was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (2) obtained by peeling off the release liner (2b) from the laminate (2) obtained in Manufacturing Example 2 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (2) with a release liner (2a).

[0272] [Manufacturing Example 5] (Production of adhesive film (3)) The coating material (X) prepared in Production Example 3 was applied to one side of a 40 μm-thick triacetyl cellulose (TAC) substrate ("ZRD40SL (ZRG)" manufactured by Fujifilm Corporation) as a substrate layer using a bar coater, and the coating material was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (1) obtained by peeling off the release liner (1b) from the laminate (1) obtained in Production Example 1 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (3) with a release liner (1a).

[0273] [Manufacturing Example 6] (Production of adhesive film (4)) The coating material (X) prepared in Production Example 3 was applied to one side of a 40 μm-thick triacetyl cellulose (TAC) substrate ("ZRD40SL (ZRG)" manufactured by Fujifilm Corporation) as a substrate layer using a bar coater, and the coating material was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (2) obtained by peeling off the release liner (2b) from the laminate (2) obtained in Manufacturing Example 2 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (4) with a release liner (2a).

[0274] [Manufacturing Example 7] (Production of adhesive film (5)) The coating material (X) prepared in Production Example 3 was applied to one side of a 50 μm-thick polyethylene terephthalate (PET) substrate ("T100C50" manufactured by Mitsubishi Chemical Corporation) (hereinafter sometimes referred to as PET50) as a substrate layer using a bar coater, and the coating was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (1) obtained by peeling off the release liner (1b) from the laminate (1) obtained in Production Example 1 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (5) with a release liner (1a).

[0275] [Manufacturing Example 8] (Production of adhesive film (6)) The coating material (X) prepared in Production Example 3 was applied to one side of a 50 μm-thick polyethylene terephthalate (PET) substrate ("T100C50" manufactured by Mitsubishi Chemical Corporation) (hereinafter sometimes referred to as PET50) as a substrate layer using a bar coater, and the coating was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (2) obtained by peeling off the release liner (2b) from the laminate (2) obtained in Production Example 2 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (6) with a release liner (2a).

[0276] [Manufacturing Example 9] (Production of adhesive film (7)) The coating material (X) prepared in Production Example 3 was applied to one side of a 75 μm-thick polyethylene terephthalate (PET) substrate ("T100-75S" manufactured by Mitsubishi Chemical Corporation) (hereinafter, sometimes referred to as PET75) as a substrate layer using a bar coater, and the coating was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (1) obtained by peeling off the release liner (1b) from the laminate (1) obtained in Production Example 1 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (7) with a release liner (1a).

[0277] [Manufacturing Example 10] (Production of adhesive film (8)) The coating material (X) prepared in Production Example 3 was applied to one side of a 75 μm-thick polyethylene terephthalate (PET) substrate ("T100-75S" manufactured by Mitsubishi Chemical Corporation) (hereinafter, sometimes referred to as PET75) as a substrate layer using a bar coater, and the coating was dried by heating at 130°C for 2 minutes to prepare a substrate with an antistatic layer having a 40 nm-thick transparent antistatic layer on one side of the substrate. The adhesive layer (2) obtained by peeling off the release liner (2b) from the laminate (2) obtained in Manufacturing Example 2 was attached to the side opposite the antistatic layer of the prepared substrate with an antistatic layer using a hand roller, and the laminate was heated and pressed at 50°C and 0.5 MPa for 15 minutes to obtain an adhesive film (8) with a release liner (2a).

[0278] [Manufacturing Example 11] (Protective film manufacturing) 100 parts by weight of 2-ethylhexyl acrylate (2EHA) as monomer components, 4 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.2 parts by weight of 2,2'-azobisisobutyronitrile as polymerization initiator, and 182 parts by weight of ethyl acetate as polymerization solvent were charged into a separable flask and stirred for 1 hour while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, the temperature was raised to 60°C and reacted for 4.5 hours, then raised to 70°C and reacted for 4.5 hours, yielding an acrylic polymer solution with a solids concentration of 35.5 wt%. The weight-average molecular weight of the acrylic polymer was 800,000. A pressure-sensitive adhesive solution was prepared by mixing 100 parts by weight of the resulting acrylic polymer with 0.03 parts by weight of a tin catalyst (Tokyo Fine Chemical's "Envirizer OL-1"), 5 parts by weight of an isocyanate crosslinking agent (Nippon Polyurethane Industry's "Coronate HX"), 0.3 parts by weight of a surfactant (Dai-ichi Kogyo Seiyaku's "Aqualon HS-10"), toluene as a solvent, and acetylacetone as a crosslinking retarder to a solution concentration of 20%. Acetylacetone was added so that the amount was 5 parts by weight relative to the amount of solvent. The resulting adhesive solution was applied to a 50 μm thick PET film (Mitsubishi Chemical "T100C50") and dried at 130°C for 1 minute. A 50 μm thick polyethylene terephthalate (PET) film (Mitsubishi Chemical "MRQ50T100J") was then attached as a release liner to produce a protective film. The adhesive layer had a thickness of 10 μm.

[0279] [Example 1] On a 50 μm thick polyethylene terephthalate (PET) film (Mitsubishi Chemical "MRQ50T100J") (150 mm x 70 mm) as a release liner, an adhesive film (2) cut to a size of 134 mm x 70 mm was used as the adhesive film (I), and an adhesive film (5) cut to a size of 15 mm x 70 mm was used as the adhesive film (II). The adhesive films were arranged as shown in FIG. 2 so that the vertical and horizontal directions were parallel, and the horizontal sides of the adhesive film (I) and the horizontal sides of the adhesive film (II) were spaced 1 mm apart, with the adhesive layer of each adhesive film facing the release liner. The release liners of each adhesive film were removed before lamination. Next, the protective film obtained in Production Example 11 was cut to a size of 150 mm long x 70 mm wide and was attached to the base layer side of each adhesive film so that it just overlapped the release liner when viewed from the planar direction. As a result, a reinforcing film (1) was obtained in which two adhesive films (2), (5) were arranged with a gap between one release liner and one protective film. The results are shown in Table 2. Table 3 also shows the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (I) region, and the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (II) region.

[0280] [Examples 2 to 10] The same procedure as in Example 1 was carried out, except that the type of adhesive film used as adhesive film (I) and the type of adhesive film used as adhesive film (II) were changed as shown in Table 2, to obtain reinforcing films (2) to (10). The results are shown in Table 2. Table 3 also shows the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (I) region, and the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (II) region.

[0281] [Comparative Examples 1 to 10] The same procedure as in Example 1 was carried out, except that the type of adhesive film used as adhesive film (I) and the type of adhesive film used as adhesive film (II) were changed as shown in Table 2, to obtain reinforcing films (C1) to (C10). The results are shown in Table 2. Table 3 also shows the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (I) region, and the peel strength (A) of the release liner and the peel strength (B) of the protective film in the adhesive film (II) region.

[0282] [Table 2]

[0283] [Table 3] [Industrial Applicability]

[0284] The reinforced film according to the embodiment of the present invention can be suitably used, for example, for reinforcing optical components, and can be particularly suitably employed in flexible devices such as bendable devices having movable bending portions, foldable devices, and rollable devices. [Explanation of symbols]

[0285] 1000 Reinforcement Film 100 Release Liner 200 protective films 300a adhesive film 300b adhesive film 300c adhesive film 10a Base material layer 10b Base material layer 20a Adhesive layer 20b adhesive layer

Claims

1. A reinforcing film in which two or more PSA films are arranged with a gap between one release liner and one protective film, The reinforcing film is used by peeling off the release liner, adhering the film to a member, and then peeling off the protective film, each of the two or more PSA films comprises a base layer and a PSA layer; the PSA layers of the two or more PSA films are directly laminated to one release liner; The two or more PSA films include at least one PSA film (I) having a flex recovery angle of 35 degrees or more and at least one PSA film (II) having a light transmittance at 550 nm of 80% or more. Reinforcement film.

2. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (I) has a storage modulus of 1.0×10 at 85° C. 5 The reinforced film of claim 1 , wherein the modulus is less than 100 Pa.

3. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film (II) has a storage modulus of 5.0 × 10 at 170 ° C. 3 Pa or more 5.0×10 5 The reinforced film according to claim 1 or 2, wherein the modulus is less than 100 Pa.

4. The reinforcing film according to any one of claims 1 to 3, wherein the area of ​​the adhesive film (I) is larger than the area of ​​the adhesive film (II).

5. The reinforcing film according to claim 1 , which is a reinforcing film for optical members.

Images