Laminate

Abstract

Provided is a laminate comprising a surface protective film and an adherend, in which deformation marks caused by deformation due to an external force are less likely to remain, the initial release force of the surface protective film from the adherend is moderate, and the change over time of the release force of the surface protective film from the adherend is small. A laminate according to an embodiment of the present invention comprises a surface protective film and an adherend, the surface protective film having a substrate and an adhesive layer, the adhesive layer being directly laminated with the adherend, the water contact angle of the surface of the adherend on the surface protective film side being 85 DEG or more, and the water contact angle of the surface of the adherend on the surface protective film side being 85 DEG or more. The arithmetic mean surface roughness Ra of the surface of the adherend on the surface protective film side is 0.6 [mu] m or less, and the laminate is at least one selected from the group consisting of (i) and (ii): (i) the creep recovery value of the adhesive layer is 96% or more; (ii) The shear modulus (G) of the surface protective film is 39.0 N / 50 mm3 or less.

Description

Technical Field

[0001] The present invention relates to a laminated body. Background Art

[0002] A surface protective film is provided on the surface of an optical component for the purpose of surface protection, imparting impact resistance, etc. Representative examples of surface protective films include: a surface protective film that is temporarily bonded to the device before use such as assembly, processing, and transportation of the device and then peeled off before use of the device (a surface protective film used as an engineering material); and a surface protective film that is used while remaining bonded to the device surface during use of the device (a surface protective film for the purpose of permanent bonding) (see, for example, Patent Document 1).

[0003] Surface protection films used as engineering materials and surface protection films for permanent bonding both have an adhesive layer on the main surface of a film substrate and are bonded to the surface of an adherend to be protected via the adhesive layer (see, for example, Patent Document 2).

[0004] A laminate having a laminate structure in which an optical member or the like is used as an adherend and a pressure-sensitive adhesive layer of a surface protection film is bonded to the adherend has conventionally had the following problems.

[0005] If deformation marks remain due to deformation of the laminated body caused by external force during handling as described above, the laminated body may become a defective product and the yield rate may decrease.

[0006] In the laminate as described above, if the initial peeling force of the surface protective film from the adherend is too low, the surface protective film may be lifted from the adherend; when the release liner provided on the side of the adherend opposite to the surface protective film (i.e., the release liner in the laminated structure of release liner / adherend / surface protective film) is peeled off, the following poor peeling (peeling at an unintended location) may occur: peeling at the interface between the surface protective film and the adherend occurs compared to peeling at the interface between the adherend and the release liner.

[0007] In such a laminate, if the initial peeling force of the surface protection film from the adherend is too high, the surface protection film may not be peeled from the adherend.

[0008] In such a laminate, if the peeling force of the surface protection film from the adherend increases significantly over time, the surface protection film may not be peeled from the adherend.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 3518677

[0012] Patent Document 2: Japanese Patent No. 6249617 Gazette Summary of the Invention

[0013] Problems to be Solved by the Invention

[0014] The technical problem of the present invention is to provide a laminate including a surface protective film and an adherend, in which deformation marks caused by deformation due to external force are not likely to remain, the initial peeling force of the surface protective film from the adherend is appropriate, and the change over time of the peeling force of the surface protective film from the adherend is small.

[0015] Solutions to the Problems

[0016] [1] A laminate according to an embodiment of the present invention includes a surface protective film and an adherend. The surface protective film has a base material and an adhesive layer, and the adhesive layer is directly laminated with the adherend. The water contact angle of the surface of the adherend on the surface protective film side is 85° or more, the arithmetic mean surface roughness Ra of the surface of the adherend on the surface protective film side is 0.6 μm or less, and the creep recovery value of the adhesive layer is 96% or more.

[0017] [2] A laminate according to another embodiment of the present invention includes a surface protective film and an adherend. The surface protective film has a base material and an adhesive layer, and the adhesive layer is directly laminated with the adherend. The water contact angle of the surface of the adherend on the surface protective film side is 85° or more, the arithmetic mean surface roughness Ra of the surface of the adherend on the surface protective film side is 0.6 μm or less, and the shear modulus G of the surface protective film is 39.0 N / 50 mm 3 as follows.

[0018] [3] It may be the laminate according to the above [1] or [2], wherein the water contact angle is 85° to 105°.

[0019] [4] It may be the laminate according to any one of the above [1] to [3], wherein the arithmetic mean surface roughness Ra is 0.1 μm or less.

[0020] [5] It may be the laminate according to the above [1], [3] or [4], wherein the creep recovery value is 99% or more.

[0021] [6] It may be the laminate according to any one of the above [2] to [4], wherein the shear modulus G is 30.0 N / 50 mm 3 as follows.

[0022] Advantages of the Invention

[0023] According to the present invention, a laminate can be provided, which includes a surface protective film and an adherend. In the laminate, deformation marks caused by deformation due to an external force are not likely to remain, the initial peeling force of the surface protective film from the adherend is appropriate, and the change over time in the peeling force of the surface protective film from the adherend is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic cross-sectional view showing one embodiment of the laminate of the present invention.

[0025] Figure 2 FIG. is a schematic explanatory view for explaining a method of evaluating the deformation of the laminate. DETAILED DESCRIPTION OF THE INVENTION

[0026] In the case where the expression "weight" is present in this specification, it can also be replaced with "mass", which is a SI unit customarily used to represent weight.

[0027] In the case where the expression "(meth)acrylic acid" is present in this specification, it means "acrylic acid and / or methacrylic acid", in the case where the expression "(meth)acrylate" is present, it means "acrylate and / or methacrylate", in the case where the expression "(meth)allyl" is present, it means "allyl and / or methallyl", and in the case where the expression "(meth)acrolein" is present, it means "acrolein and / or methacrolein".

[0028] The laminate according to an embodiment of the present invention includes a surface protective film and an adherend. The surface protective film has a base material and an adhesive layer.

[0029] In the laminate according to an embodiment of the present invention, the adhesive layer is directly laminated on the adherend.

[0030] Figure 1 FIG. is an embodiment of the laminate of the present invention. The laminate 1000 includes a surface protective film 100 and an adherend 200. The surface protective film 100 has a base material 10 and an adhesive layer 20. The adhesive layer 20 is directly laminated on the adherend 200.

[0031] As long as the laminate according to an embodiment of the present invention includes a surface protective film and an adherend, it can include any appropriate other layers within the range that does not impair the effects of the present invention. Examples of such other layers include glass, a display, a photographing device, a lens, and a (semi)reflective mirror.

[0032] The total thickness of the laminated body of the embodiment of the present invention can be appropriately set according to the type of adherend and the type of other layers that can be included. Typically, the total thickness of the laminated body of the embodiment of the present invention is preferably 10 μm to 1000 μm, more preferably 25 μm to 800 μm, further preferably 40 μm to 600 μm, and particularly preferably 50 μm to 500 μm.

[0033] In the laminate of the embodiment of the present invention, the water contact angle of the surface of the surface protective film side of the adherend (the side of the laminated surface protective film) is preferably 85° or more, more preferably 85° to 110°, further preferably 85° to 105°, further preferably 90° to 100°, particularly preferably 95° to 100°, and most preferably 95° to 99°. If the above-mentioned water contact angle is within the above-mentioned range, the effect of the present invention can be further reflected. If the above-mentioned water contact angle deviates from the above-mentioned range and is too small, the surface protective film is prone to excessive adhesion to the adherend. For example, the initial peeling force of the surface protective film from the adherend is increased, and the surface protective film may not be peeled off from the adherend. The peeling force of the surface protective film from the adherend increases excessively over time, and the surface protective film may not be peeled off from the adherend. If the water contact angle deviates from the above range and is too large, the surface protective film is not easy to be overly adhered to the adherend. For example, the initial peeling force of the surface protective film from the adherend is too low, and the surface protective film may be lifted from the adherend. When the release liner provided on the side of the adherend opposite to the surface protective film (i.e., the release liner in the laminated structure of release liner / adherend / surface protective film) is peeled off, the following poor peeling (peeling at an unintended location) may occur: peeling at the interface between the surface protective film and the adherend occurs compared to peeling at the interface between the adherend and the release liner.

[0034] In the laminate of the embodiment of the present invention, the arithmetic mean surface roughness Ra of the surface of the surface protective film side (laminated surface protective film side) of the adherend is preferably 0.6 μm or less, more preferably 0.35 μm or less, further preferably 0.2 μm or less, particularly preferably 0.1 μm or less, and most preferably 0.08 μm or less. The lower limit of the arithmetic mean surface roughness Ra is as small as possible, preferably 0 μm or more. If the arithmetic mean surface roughness Ra is within the above range, the effect of the present invention can be further reflected. If the arithmetic mean surface roughness Ra deviates from the above range and is too large, for example, when the thickness of the adhesive layer possessed by the surface protective film is large, the peeling force of the surface protective film from the adherend increases excessively over time, and the surface protective film may not be peeled off from the adherend.

[0035] In the laminate according to an embodiment of the present invention, the creep recovery value of the adhesive layer of the surface protective film is preferably 96% or more, more preferably 97% or more, still more preferably 98% or more, and particularly preferably 99% or more. If the creep recovery value is within the above range, the effects of the present invention can be further manifested. If the creep recovery value deviates from the above range and is too small, deformation marks caused by deformation due to external force may easily remain.

[0036] In the laminate according to an embodiment of the present invention, the shear modulus G of the surface protective film is preferably 39.0 N / 50 mm 3 More preferably, it is 27.0 N / 50 mm or less 3 ~39.0 N / 50 mm 3 Still more preferably, it is 27.5 N / 50 mm 3 ~38.5 N / 50 mm 3 Particularly preferably, it is 28.0 N / 50 mm 3 ~38.0 N / 50 mm 3 If the shear modulus G is within the above range, the effects of the present invention can be further manifested. If the shear modulus G deviates from the above range, deformation marks caused by deformation due to external force may easily remain.

[0037] In the laminate according to an embodiment of the present invention, the thickness of the adhesive layer of the surface protective film is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, particularly preferably 15 μm or more, and most preferably 18 μm or more. The upper limit value of the thickness of the adhesive layer is preferably 150 μm or less, more preferably 100 μm or less, still more preferably 80 μm or less, particularly preferably 50 μm or less, and most preferably 30 μm or less. If the thickness of the adhesive layer is within the above range, the effects of the present invention can be further manifested. If the thickness of the adhesive layer deviates from the above range and is too small, deformation marks caused by deformation due to external force may easily remain. If the thickness of the adhesive layer deviates from the above range and is too large, it may not be applicable to thin devices in the case where the adherend is an optical member or the like.

[0038] 《《1. Surface protective film》》

[0039] The surface protective film has a substrate and an adhesive layer. One embodiment of the surface protective film is composed of a substrate and an adhesive layer (for example, as Figure 1 shown, the surface protective film 100 is composed of a substrate 10 and an adhesive layer 20).

[0040] The surface protective film may have any other appropriate layers other than the substrate and the adhesive layer within the range that does not impair the effects of the present invention.

[0041] As such other layers, for example, the following can be cited: an easy - adhesion layer, an easy - slip layer, an anti - adhesion layer, an antistatic layer, an antireflection layer, an anti - oligomer layer, a release liner provided on the surface of the adhesive layer on the side opposite to the substrate.

[0042] The constituent elements of the surface protective film (substrate, adhesive layer, other layers as required, etc.) can contain any appropriate additives within the range that does not impair the effects of the present invention. As such additives, for example, the following can be cited: antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, antistatic agents.

[0043] On the side of the adhesive layer opposite to the substrate, a release liner can be provided as required for protection during the period until it is laminated with the adherend.

[0044] As the release liner, for example, the following can be cited: a release liner obtained by subjecting the surface of a substrate (liner substrate) such as paper or a plastic film to silicone treatment; a release liner obtained by laminating a polyolefin - based resin on the surface of a substrate (liner substrate) such as paper or a plastic film, etc. Regarding the plastic film as the liner substrate, for example, the following can be cited: polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene - vinyl acetate copolymer film, etc.

[0045] The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, further preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

[0046] 《1 - 1. Substrate》

[0047] The substrate can be a substrate composed of one layer or a substrate composed of a laminated structure of two or more layers.

[0048] The thickness of the substrate can be any appropriate thickness within the range that does not impair the effects of the present invention. Considering the aspect of further embodying the effects of the present invention, the thickness of the substrate is preferably 5 μm to 1000 μm, more preferably 10 μm to 800 μm, further preferably 20 μm to 600 μm, and particularly preferably 30 μm to 400 μm.

[0049] As the material of the substrate, any appropriate material can be used within the range that does not impair the effects of the present invention. Considering the aspect of further embodying the effects of the present invention, as such materials, plastics are preferably cited.

[0050] As the plastic, any suitable plastic can be adopted within the scope that does not damage the effects of the present invention. Considering aspects that can further embody the effects of the present invention, preferred plastics include thermoplastic resins.

[0051] Examples of thermoplastic resins include: polyesters, acrylic resins, urethane resins, polycarbonates, triacetyl cellulose (TAC), polyolefins (olefin homopolymers, copolymers of olefins and other monomers), polyamides (nylons), wholly aromatic polyamides (aramids), polyimides (PI), polyvinyl chlorides (PVC), polyvinyl acetates, cyclic olefin polymers.

[0052] Considering aspects that can further embody the effects of the present invention, polyesters are preferred as thermoplastic resins. Examples of polyesters include: polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polyethylene terephthalate (PET) is preferred considering aspects that can further embody the effects of the present invention.

[0053] 《1-2. Adhesive Layer》

[0054] The adhesive layer can be an adhesive layer composed of one layer or an adhesive layer composed of a laminated structure of two or more layers.

[0055] The thickness of the adhesive layer is as described above.

[0056] The adhesive constituting the adhesive layer is preferably at least one selected from the group consisting of acrylic adhesives, urethane adhesives, and silicone adhesives.

[0057] The adhesive layer is more preferably composed of an acrylic adhesive.

[0058] The acrylic adhesive is formed from an acrylic adhesive composition.

[0059] The acrylic adhesive can be defined as a substance formed from an acrylic adhesive composition. The reason is that for acrylic adhesives, the acrylic adhesive composition undergoes crosslinking reactions, etc. through heating, ultraviolet irradiation, etc., and thus becomes an acrylic adhesive. Therefore, the acrylic adhesive cannot be directly determined by its structure. In addition, there are generally impractical situations ("impossible / impractical situations"). Therefore, according to the definition of "a substance formed from an acrylic adhesive composition", the acrylic adhesive is properly determined as a "substance".

[0060] The adhesive layer can be formed by any suitable method. As such methods, for example, the following methods can be cited: applying an adhesive composition that forms an adhesive onto any suitable substrate, where the adhesive constitutes the adhesive layer, heating, drying as needed, curing as needed, and forming an adhesive layer on the substrate; applying an adhesive composition that forms an adhesive onto any suitable film such as a release liner, where the adhesive constitutes the adhesive layer, heating, drying as needed, curing as needed, forming an adhesive layer on the film, and laminating any suitable substrate onto the adhesive layer and transferring, thereby forming an adhesive layer on the substrate.

[0061] As a method of applying the acrylic adhesive composition, any suitable method can be adopted within the range that does not impair the effects of the present invention. As such coating methods, for example, the following can be cited: roll coating method, gravure roll coating method, reverse roll coating method, roll kiss coat method, dip roll coating method, bar coating method, roller brush coating method, spraying method, blade coating method, air knife coating method, comma coating method, direct coating method, die coating method.

[0062] Heating and drying of the acrylic adhesive composition can be carried out by any suitable method within the range that does not impair the effects of the present invention. As such heating and drying methods, for example, the following can be cited: heating to 60°C to 180°C; for example, aging treatment is carried out at a temperature around room temperature.

[0063] Curing of the acrylic adhesive composition can be carried out by any suitable method within the range that does not impair the effects of the present invention. As such curing methods, for example, the following can be cited: heat, ultraviolet irradiation, laser beam irradiation, α-ray irradiation, β-ray irradiation, γ-ray irradiation, X-ray irradiation, electron beam irradiation.

[0064] In terms of further embodying the effects of the present invention, the acrylic adhesive composition preferably contains an acrylic polymer.

[0065] <1-2-a. Acrylic polymer>

[0066] The acrylic polymer is a substance that can be called a so-called base polymer in the field of acrylic adhesives. The acrylic polymer can be only one kind or two or more kinds.

[0067] That is, a preferred embodiment of the adhesive layer is as follows: the adhesive layer is composed of an acrylic adhesive, the acrylic adhesive is formed from an acrylic adhesive composition, and the acrylic adhesive composition contains an acrylic polymer as a base polymer.

[0068] The content ratio of the acrylic polymer in the acrylic adhesive composition is preferably 60% to 99.9% by weight in terms of solid content, more preferably 65% to 99.9% by weight, still more preferably 70% to 99.9% by weight, particularly preferably 75% to 99.9% by weight, and most preferably 80% to 99.9% by weight.

[0069] As the acrylic polymer, any suitable acrylic polymer can be adopted within the range not impairing the effects of the present invention.

[0070] In terms of further embodying the effects of the present invention, the weight-average molecular weight of the acrylic polymer is preferably 300,000 to 2,000,000, more preferably 350,000 to 1,500,000, still more preferably 400,000 to 1,000,000, and particularly preferably 500,000 to 1,000,000. If the above weight-average molecular weight is too low, there is a tendency to contain more low-molecular-weight components, and plastic deformation of the low-molecular-weight components may occur. Therefore, deformation marks caused by deformation due to external forces are likely to remain.

[0071] A preferred embodiment of the acrylic polymer is an acrylic polymer prepared by solution polymerization using a polymerization initiator. As a method of polymerization using a polymerization initiator, for example, any suitable method such as a conventionally well-known method can be adopted within the range not impairing the effects of the present invention.

[0072] The acrylic polymer is a substance obtained by polymerizing monomer components (M). The monomer components (M) mentioned here do not include the crosslinking agents that may be contained in the acrylic adhesive composition. When obtaining the acrylic polymer by polymerization, in addition to using the monomer components (M) and the polymerization initiator, any suitable additives can be used within the range not impairing the effects of the present invention.

[0073] The acrylic polymer can be defined as a substance obtained by polymerizing monomer components (M). The reason is that for the acrylic polymer, it becomes an acrylic polymer through the polymerization reaction of the monomer components (M), and the acrylic polymer cannot be directly determined by its structure. In addition, there are roughly impractical situations ( "impossible / impractical situations"). Therefore, according to the definition of "a substance obtained by polymerizing monomer components (M)", the acrylic polymer is appropriately determined as a "substance".

[0074] In terms of further demonstrating the effects of the present invention, the glass transition temperature Tg of the acrylic polymer is preferably 0 °C or lower, more preferably -10 °C or lower, further preferably -15 °C or lower, particularly preferably -20 °C or lower, and most preferably -25 °C or lower. The lower limit value of the above glass transition temperature Tg is preferably -100 °C or higher, more preferably -90 °C or higher, and further preferably -80 °C or higher. By adjusting the glass transition temperature Tg of the acrylic polymer to the above specific range, the effects of the present invention can be further demonstrated.

[0075] Here, the glass transition temperature Tg of the acrylic polymer refers to the value calculated according to the Fox formula based on the glass transition temperature Tg of the homopolymer of each monomer constituting the acrylic polymer and the weight fraction (copolymerization ratio based on weight) of the monomer. The Fox formula is the relational formula between the glass transition temperature Tg of the copolymer and the glass transition temperature Tgi of the homopolymer obtained by homopolymerizing each monomer constituting the copolymer, as shown below.

[0076] 1 / Tg = Σ(Wi / Tgi)

[0077] In the above Fox formula, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction (copolymerization ratio based on weight) of monomer i in the copolymer, and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K). As the glass transition temperature Tg of the homopolymer, the value recorded in the known literature is adopted.

[0078] As the glass transition temperature Tg of the homopolymer, for example, the following values can be specifically used.

[0079] Homopolymer of n-butyl acrylate (BA): -55 °C.

[0080] Homopolymer of lauryl acrylate (LA): -23 °C.

[0081] Homopolymer of 2-ethylhexyl acrylate (2EHA): -70 °C.

[0082] Homopolymer of methyl methacrylate (MMA): 105 °C.

[0083] Homopolymer of 2-hydroxyethyl acrylate (HEA): -15 °C.

[0084] Homopolymer of 4-hydroxybutyl acrylate (4HBA): -40 °C.

[0085] Homopolymer of N-vinyl-2-pyrrolidone (NVP): 80 °C.

[0086] Homopolymer of vinyl acetate (VAc): 30 °C.

[0087] Homopolymer of acrylic acid (AA): 106 °C.

[0088] Regarding the glass transition temperature Tg of homopolymers other than those exemplified above, the values described in the "Polymer Handbook" (Third Edition, John Wiley & Sons, Inc., 1989) can be used. When there are multiple values described in the above "Polymer Handbook", the conventional value is adopted. Regarding monomers not described in the above "Polymer Handbook", the catalog value of the monomer manufacturing company is adopted. As the glass transition temperature Tg of the homopolymer of a monomer for which there is no description in the above "Polymer Handbook" and no catalog value provided by the monomer manufacturing company, the value obtained by the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 is used.

[0089] The monomer component (M) preferably contains an alkyl (meth)acrylate (a) and a monomer (b) containing a polar group. The alkyl (meth)acrylate (a) can be only one kind or two or more kinds. The monomer (b) containing a polar group can be only one kind or two or more kinds.

[0090] It should be noted that the alkyl group in the ester part of the alkyl (meth)acrylate (a) (hereinafter sometimes simply referred to as "the alkyl group in the ester part") does not include an alkyl group containing a hydroxyl group and an alkyl group containing a polar group other than a hydroxyl group. Therefore, the alkyl (meth)acrylate (a) can be clearly distinguished from the monomer (b) containing a polar group.

[0091] In terms of further demonstrating the effects of the present invention, the content ratio of the alkyl (meth)acrylate (a) in the monomer component (M) is preferably 40% by weight to 99.999% by weight.

[0092] In the case where the monomer (b) containing a polar group contained in the monomer component (M) is an embodiment in which it contains a monomer (b1) containing a hydroxyl group and does not contain a monomer (b2) having a polar group other than a hydroxyl group, in particular, in terms of further demonstrating the effects of the present invention, the content ratio of the alkyl (meth)acrylate (a) in the monomer component (M) is more preferably 60% by weight to 99.999% by weight, further preferably 80% by weight to 99.99% by weight, further preferably 85% by weight to 99.9% by weight, particularly preferably 90% by weight to 99.5% by weight, and most preferably 95% by weight to 99% by weight.

[0093] In the case of the embodiment where the polar group-containing monomer (b) contained in the monomer component (M) does not contain the hydroxyl group-containing monomer (b1) as described later and contains the monomer (b2) having a polar group other than the hydroxyl group, in particular, in terms of further exhibiting the effects of the present invention, the content ratio of the (meth)acrylic acid alkyl ester (a) in the monomer component (M) is more preferably 43% by weight to 90% by weight, further preferably 46% by weight to 80% by weight, particularly preferably 48% by weight to 70% by weight, and most preferably 50% by weight to 60% by weight.

[0094] In terms of further exhibiting the effects of the present invention, in the (meth)acrylic acid alkyl ester (a), the alkyl group of 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, further preferably an alkyl group having 1 to 16 carbon atoms, particularly preferably an alkyl group having 1 to 14 carbon atoms, and most preferably an alkyl group having 1 to 12 carbon atoms.

[0095] In terms of further exhibiting the effects of the present invention, the alkyl group of the ester moiety is preferably a linear alkyl group. Here, the linear includes both straight-chain and branched-chain.

[0096] Examples of the (meth)acrylic acid alkyl ester (a) include: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, 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, eicosyl (meth)acrylate, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate.

[0097] In terms of further demonstrating the effects of the present invention, the (meth)acrylic acid alkyl ester (a) preferably contains a (meth)acrylic acid alkyl ester (a1) whose glass transition temperature Tg of the homopolymer is in the range of -80°C to -60°C. As such a (meth)acrylic acid alkyl ester (a1), for example, 2-ethylhexyl acrylate (2EHA) (the glass transition temperature Tg of its homopolymer = -70°C) can be cited.

[0098] As the glass transition temperature Tg of the homopolymer of the (meth)acrylic acid alkyl ester (a1), for example, the following values can be specifically used.

[0099] Homopolymer of n-butyl acrylate (BA): -55°C.

[0100] Homopolymer of lauryl acrylate (LA): -23°C.

[0101] Homopolymer of 2-ethylhexyl acrylate (2EHA): -70°C.

[0102] Regarding the glass transition temperature Tg of homopolymers other than those exemplified above, the values described in the "Polymer Handbook" (Third Edition, John Wiley & Sons, Inc., 1989) can be used. In the case where multiple values are described in the above "Polymer Handbook", conventional values are adopted. Regarding monomers not described in the above "Polymer Handbook", the catalog values of the monomer manufacturing companies are adopted. As the glass transition temperature Tg of the homopolymer of a monomer for which there is no description in the above "Polymer Handbook" and no catalog value provided by the monomer manufacturing company, the value obtained by the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 is used.

[0103] In terms of further demonstrating the effects of the present invention, the content ratio of the (meth)acrylic acid alkyl ester (a1) in the total amount of the (meth)acrylic acid alkyl ester (a) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, still 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.

[0104] In terms of aspects that can demonstrate the effects of the present invention, the (meth)acrylic acid alkyl ester (a1) with a glass transition temperature Tg of the homopolymer in the range of -80°C to -60°C may affect the adhesive properties and the like of the acrylic polymer. By preferably including the (meth)acrylic acid alkyl ester (a1) with a glass transition temperature Tg of the homopolymer in the range of -80°C to -60°C in the above-mentioned content ratio in the (meth)acrylic acid alkyl ester (a), the effects of the present invention can be further demonstrated.

[0105] (Meth)acrylic acid alkyl ester (a) may include (meth)acrylic acid alkyl esters other than (meth)acrylic acid alkyl ester (a1). In terms of aspects that can further demonstrate the effects of the present invention, the content ratio of the (meth)acrylic acid alkyl ester other than (meth)acrylic acid alkyl ester (a1) in the total amount of (meth)acrylic acid alkyl ester (a) is preferably 0% by weight to 50% by weight, more preferably 0% by weight to 30% by weight, further preferably 0% by weight to 20% by weight, particularly preferably 0% by weight to 10% by weight, and most preferably 0% by weight to 5% by weight.

[0106] In terms of aspects that can further demonstrate the effects of the present invention, the content ratio of the polar group-containing monomer (b) in the monomer component (M) is preferably 1% by weight to 60% by weight, more preferably 5% by weight to 60% by weight, further preferably 10% by weight to 60% by weight, particularly preferably 15% by weight to 60% by weight, and most preferably 20% by weight to 60% by weight.

[0107] As the polar group-containing monomer (b), as long as it is a monomer having a polar group, any suitable monomer can be used within the range that does not damage the effects of the present invention. As such a polar group-containing monomer (b), the following can be cited: Embodiment (I) including a hydroxyl group-containing monomer (b1), and Embodiment (II) not including a hydroxyl group-containing monomer (b1). It should be noted that the "hydroxyl group" mentioned here does not include the -OH group of the carboxyl group (-COOH).

[0108] As the polar group-containing monomer (b), as long as it can adjust the glass transition temperature Tg of the acrylic polymer to the above-mentioned preferred range, it can be appropriately selected from the above-mentioned embodiments.

[0109] The hydroxyl group-containing monomer (b1) may be only one kind, or two or more kinds. The monomer (b2) having a polar group other than a hydroxyl group may be only one kind, or two or more kinds.

[0110] Examples of the hydroxyl group-containing monomer (b1) 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.

[0111] In terms of further demonstrating the effects of the present invention, the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1) is preferably from -60°C to -10°C, more preferably from -55°C to -10°C, still more preferably from -45°C to -10°C, particularly preferably from -35°C to -10°C, and most preferably from -25°C to -10°C. The glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1) may affect the adhesion properties of the acrylic polymer, etc. By using a hydroxyl group-containing monomer having a glass transition temperature Tg of the homopolymer within the above range as the hydroxyl group-containing monomer (b1) that can be included in the monomer component (M), the effects of the present invention can be further demonstrated.

[0112] Regarding the glass transition temperature Tg of the homopolymer of the hydroxyl group-containing monomer (b1), the description of the glass transition temperature Tg of the homopolymer of the alkyl (meth)acrylate (a1) can be cited.

[0113] In terms of further demonstrating the effects of the present invention, preferred examples of the hydroxyl group-containing monomer (b1) 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. More preferred examples include hydroxyalkyl (meth)acrylates in which the alkyl moiety of the hydroxyalkyl group is a linear alkyl group having 2 to 4 carbon atoms. Still more preferred examples include 2-hydroxyethyl acrylate (HEA) (the glass transition temperature Tg of its homopolymer = -15°C) and 4-hydroxybutyl acrylate (4HBA) (the glass transition temperature Tg of its homopolymer = -40°C). Particularly preferred is 2-hydroxyethyl acrylate (HEA) (the glass transition temperature Tg of its homopolymer = -15°C).

[0114] In the case of Embodiment (I) where the monomer (b) containing a polar group must contain a hydroxyl group-containing monomer (b1), in consideration of further demonstrating the effects of the present invention, the content ratio of the hydroxyl group-containing monomer (b1) in the monomer (b) containing a polar group is preferably 1% by weight to 100% by weight, more preferably 10% by weight to 100% by weight, further preferably 50% by weight to 100% by weight, further preferably 70% 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.

[0115] In Embodiment (I) where a hydroxyl group-containing monomer (b1) must be contained, the monomer (b) containing a polar group may contain a monomer (b2) having a polar group other than a hydroxyl group. In this case, in consideration of further demonstrating the effects of the present invention, the content ratio of the monomer (b2) having a polar group other than a hydroxyl group in the monomer (b) containing a polar group is preferably 0% by weight to 99% by weight, more preferably 0% by weight to 90% by weight, further preferably 0% by weight to 50% by weight, further preferably 0% by weight to 30% by weight, particularly preferably 0% by weight to 10% by weight, and most preferably 0% by weight to 5% by weight.

[0116] In the case of Embodiment (I) where the monomer (b) containing a polar group must contain a hydroxyl group-containing monomer (b1), in consideration of further demonstrating the effects of the present invention, the content ratio of the hydroxyl group-containing monomer (b1) in the monomer component (M) is preferably 0.001% by weight to 40% by weight, more preferably 0.01% by weight to 20% by weight, further preferably 0.1% by weight to 15% by weight, particularly preferably 0.5% by weight to 10% by weight, and most preferably 1% by weight to 5% by weight.

[0117] Examples of the monomer (b2) having a polar group other than a hydroxyl group include: carboxyl group-containing monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, acid anhydride group-containing monomers, vinyl esters, heterocyclic-containing vinyl monomers, aromatic vinyl compounds, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, isocyanate group-containing monomers, (meth)acrylates having an aromatic hydrocarbon group, aromatic vinyl compounds, olefins, dienes, vinyl ethers, (meth)acrylmorpholine, vinyl ethers, halogen group-containing monomers.

[0118] Examples of the carboxyl group-containing monomers include: acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid.

[0119] As the monomer containing a sulfonic acid group, for example, sodium vinyl sulfonate can be cited.

[0120] As the monomer containing a phosphoric acid group, for example, 2-hydroxyethyl acryloyl phosphate can be cited.

[0121] As the monomer containing a cyano group, for example, acrylonitrile and methacrylonitrile can be cited.

[0122] As the monomer containing an acid anhydride group, for example, maleic anhydride and itaconic anhydride can be cited.

[0123] As vinyl esters, for example, vinyl acetate (VAc), vinyl propionate, and vinyl laurate can be cited.

[0124] As the vinyl monomer containing a heterocyclic ring, for example, N-vinyl-2-pyrrolidone, (meth)acryloylmorpholine, N-vinylpiperidone, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, vinylpyridine, vinylpyrimidine, and vinyloxazole can be cited.

[0125] As aromatic vinyl compounds, for example, styrene and vinyltoluene can be cited.

[0126] As the monomer containing an amide group, for example, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide, and N-hydroxyethyl(meth)acrylamide can be cited.

[0127] As the monomer containing an imide group, for example, cyclohexyl maleimide and isopropyl maleimide can be cited.

[0128] As the monomer containing an amino group, for example, aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate can be cited.

[0129] As the monomer containing an epoxy group, for example, glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate can be cited.

[0130] As the monomer containing an isocyanate group, for example, 2-methacryloyloxyethyl isocyanate can be cited.

[0131] As the (meth)acrylate having an aromatic hydrocarbon group, for example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and benzyl (meth)acrylate can be cited.

[0132] As olefins and dienes, for example, ethylene, butadiene, isoprene, and isobutene can be cited.

[0133] As vinyl ethers, vinyl alkyl ethers can be cited as an example.

[0134] As monomers having a halogen-containing group, vinyl chloride can be cited as an example.

[0135] In terms of further demonstrating the effects of the present invention, the glass transition temperature Tg of the homopolymer of the monomer (b2) having a polar group other than a hydroxyl group is preferably 0°C to 130°C, more preferably 10°C to 120°C, and still more preferably 20°C to 110°C.

[0136] Regarding the glass transition temperature Tg of the homopolymer of the monomer (b2) having a polar group other than a hydroxyl group, the description of the glass transition temperature Tg of the homopolymer of the (meth)acrylic acid alkyl ester (a1) can be cited.

[0137] One embodiment of the monomer (b2) having a polar group other than a hydroxyl group includes a monomer (b2-1) having a glass transition temperature Tg of the homopolymer of 0°C to 60°C and a monomer (b2-2) having a glass transition temperature Tg of the homopolymer of 70°C to 130°C. In this embodiment, in terms of further demonstrating the effects of the present invention, the content ratio of the monomer (b2-1) having a polar group other than a hydroxyl group in the monomer (b2) having a polar group other than a hydroxyl group is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, still more preferably 80% by weight to 99% by weight, and particularly preferably 90% by weight to 99% by weight. In this embodiment, in terms of further demonstrating the effects of the present invention, the content ratio of the monomer (b2-2) having a polar group other than a hydroxyl group in the monomer (b2) having a polar group other than a hydroxyl group is preferably 1% by weight to 50% by weight, more preferably 1% by weight to 30% by weight, still more preferably 1% by weight to 20% by weight, and particularly preferably 1% by weight to 10% by weight. In this embodiment, the total content ratio of the monomer (b2-1) having a polar group other than a hydroxyl group and the monomer (b2-2) having a polar group other than a hydroxyl group in the monomer (b2) having a polar group other than a hydroxyl group is preferably 60% by weight to 100% by weight, more preferably 80% by weight to 100% by weight, still more preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight to 100% by weight.

[0138] The glass transition temperature Tg of the homopolymer of the monomer (b2-1) having a polar group other than a hydroxyl group is 0 °C to 60 °C, and the glass transition temperature Tg is preferably 10 °C to 50 °C, more preferably 20 °C to 40 °C. As such a monomer (b2-1) having a polar group other than a hydroxyl group, for example, vinyl acetate (VAc) can be cited (the glass transition temperature Tg of its homopolymer is 30 °C).

[0139] The glass transition temperature Tg of the homopolymer of the monomer (b2-2) having a polar group other than a hydroxyl group is 70 °C to 130 °C, and the glass transition temperature Tg is preferably 80 °C to 120 °C, more preferably 90 °C to 110 °C. As such a monomer (b2-2) having a polar group other than a hydroxyl group, for example, acrylic acid (AA) can be cited (the glass transition temperature Tg of its homopolymer is 106 °C).

[0140] In the case of the embodiment (II) where the monomer (b) containing a polar group does not contain the monomer (b1) containing a hydroxyl group, that is, when the monomer (b2) having a polar group other than a hydroxyl group must be included, in terms of further demonstrating the effects of the present invention, the content ratio of the monomer (b2) having a polar group other than a hydroxyl group in the monomer component (M) is preferably 10% by weight to 57% by weight, more preferably 20% by weight to 54% by weight, further preferably 30% by weight to 52% by weight, and particularly preferably 40% by weight to 50% by weight.

[0141] As an embodiment, the monomer component (M) preferably contains an alkyl (meth)acrylate (a) and a monomer (b) containing a polar group. The content ratio of the alkyl (meth)acrylate (a) in the monomer component (M) is 43% by weight to 90% by weight. The alkyl (meth)acrylate (a) is an alkyl (meth)acrylate (a1) whose glass transition temperature Tg of the homopolymer is in the range of -80 °C to -60 °C. The monomer (b) containing a polar group does not contain the monomer (b1) containing a hydroxyl group and must contain the monomer (b2) having a polar group other than a hydroxyl group. The glass transition temperature Tg of the homopolymer of the monomer (b2) having a polar group other than a hydroxyl group is in the range of 0 °C to 130 °C. The content ratio of the monomer (b) containing a polar group in the monomer component (M) is 10% by weight to 57% by weight.

[0142] As an embodiment for further demonstrating the effects of the present invention, it is as follows (i) to (ix).

[0143] (i) The monomer component (M) preferably contains an alkyl (meth)acrylate (a) and a monomer (b) containing a polar group.

[0144] (ii) The content ratio of the alkyl (meth)acrylate (a) in the monomer component (M) is preferably 60% by weight to 99.999% by weight, more preferably 80% by weight to 99.99% by weight, further preferably 85% by weight to 99.9% by weight, particularly preferably 90% by weight to 99.5% by weight, and most preferably 95% by weight to 99% by weight.

[0145] (iii) The alkyl (meth)acrylate (a) preferably must contain an alkyl (meth)acrylate (a1) whose glass transition temperature Tg of the homopolymer is in the range of -80°C to -60°C.

[0146] (iv) The content ratio of the alkyl (meth)acrylate (a1) in the total amount of the alkyl (meth)acrylate (a) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, further 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.

[0147] (v) The content ratio of the monomer (b) containing a polar group in the monomer component (M) is preferably 0.001% by weight to 40% by weight, more preferably 0.01% by weight to 20% by weight, further preferably 0.1% by weight to 15% by weight, particularly preferably 0.5% by weight to 10% by weight, and most preferably 1% by weight to 5% by weight.

[0148] (vi) The monomer (b) containing a polar group preferably must contain a monomer (b1) containing a hydroxyl group.

[0149] (vii) The monomer (b1) containing a hydroxyl group preferably has a glass transition temperature Tg of its homopolymer in the range of -60°C to -10°C.

[0150] (viii) The content ratio of the monomer (b1) containing a hydroxyl group in the monomer (b) containing a polar group is preferably 1% by weight to 100% by weight, more preferably 10% by weight to 100% by weight, further preferably 50% by weight to 100% by weight, further preferably 70% 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.

[0151] (ix) The content ratio of the hydroxyl group-containing monomer (b1) in the monomer component (M) is preferably 0.001% by weight to 40% by weight, more preferably 0.01% by weight to 20% by weight, further preferably 0.1% by weight to 15% by weight, particularly preferably 0.5% by weight to 10% by weight, and most preferably 1% by weight to 5% by weight.

[0152] The monomer component (M) may contain other monomers (c) that do not correspond to either the (meth)acrylic acid alkyl ester (a) or the polar group-containing monomer (b). The other monomers (c) can be used, for example, for the purpose of adjusting the glass transition temperature Tg of the acrylic polymer or adjusting the adhesion properties. The other monomers can be only one kind or two or more kinds.

[0153] The content ratio of the other monomers (c) in the monomer component (M) is preferably 20% by weight or less, more preferably 10% by weight or less, further preferably 5% by weight or less, particularly preferably 3% by weight or less, and most preferably 1% by weight or less.

[0154] The acrylic polymer is a substance obtained by polymerizing the monomer component (M). A preferred embodiment of the acrylic polymer is an acrylic polymer prepared by solution polymerization using a polymerization initiator.

[0155] The polymerization initiator can be any suitable polymerization initiator according to the type of polymerization reaction. The polymerization initiator can be only one kind or two or more kinds.

[0156] As the polymerization initiator, typically, a thermal polymerization initiator can be cited.

[0157] The thermal polymerization initiator is preferably used when producing the acrylic polymer by solution polymerization. Examples of such thermal polymerization initiators include azo-based initiators such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanovaleric acid), azoisopentanenitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'-dimethylisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.); persulfates such as potassium persulfate and ammonium persulfate; peroxides such as di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, dilauroyl peroxide, dioctanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, benzoyl peroxide, tert-butyl peroxyisobutyrate, 1,1-bis(tert-hexylperoxy)cyclohexane, tert-butyl hydroperoxide, and hydrogen peroxide; redox initiators formed by combining peroxides with reducing agents such as the combination of persulfate and sodium bisulfite and the combination of peroxide and sodium ascorbate; substituted ethane-based initiators such as phenyl-substituted ethane; and aromatic carbonyl compounds.

[0158] The amount of the thermal polymerization initiator used can be set to any appropriate amount within the range that does not impair the effects of the present invention. Considering aspects that can further embody the effects of the present invention, 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, still 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 (M).

[0159] As the solvent used when producing the acrylic polymer by solution polymerization, any appropriate solvent can be adopted within the range that does not impair the effects of the present invention.

[0160] <1-2-b. Crosslinking Agent>

[0161] The acrylic adhesive composition may contain a crosslinking agent. By using the crosslinking agent, the cohesion of the acrylic adhesive can be improved, and the effects of the present invention can be further embodied. The crosslinking agent may be only one kind or two or more kinds.

[0162] As crosslinking agents, for example, the following can be mentioned: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, peroxides and other crosslinking agents. Considering aspects that can further embody the effects of the present invention, it is preferably at least one (component c) selected from the group consisting of isocyanate-based crosslinking agents, epoxy-based crosslinking agents, and peroxides.

[0163] As the isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including isocyanate regenerable polar groups obtained by temporarily protecting the isocyanate groups with a blocking agent or polymerization) in one molecule can be used. As the isocyanate-based crosslinking agent, for example, the following can be mentioned: aromatic isocyanates such as toluene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate.

[0164] As the isocyanate-based crosslinking agent, for example, the following can be mentioned: 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-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl isocyanate; isocyanate adducts such as trimethylolpropane / toluene diisocyanate trimer adduct (for example, manufactured by TOSOH Corporation, trade name CORONATE L), trimethylolpropane / hexamethylene diisocyanate trimer adduct (for example, manufactured by TOSOH Corporation, trade name: CORONATE HL), and isocyanurate of hexamethylene diisocyanate (for example, manufactured by TOSOH Corporation, trade name: CORONATE HX); xylylene diisocyanate trimethylolpropane adduct (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D110N), xylylene diisocyanate trimethylolpropane adduct (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATED120N), isophorone diisocyanate trimethylolpropane adduct (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D140N), hexamethylene diisocyanate trimethylolpropane adduct (for example, manufactured by Mitsui Chemicals, Inc., trade name: TAKENATE D160N); polyether polyisocyanates, polyester polyisocyanates, and their adducts with various polyols; polyfunctionalized polyisocyanates having isocyanurate bonds, biuret bonds, urethane bonds, etc. Among them, considering aspects that can well balance deformability and cohesion, aromatic isocyanates and alicyclic isocyanates are preferred.

[0165] As the epoxy crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy 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, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diethylene glycol diglycidyl adipate, diethylene glycol diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Examples of commercially available products of the epoxy crosslinking agent include products with the trade names "TETRAD-C" and "TETRAD-X" manufactured by MITSUBISHI GAS CHEMICAL COMPANY.

[0166] Examples of the peroxide include: benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, di-tert-butyl peroxide-3,3,5-trimethylcyclohexane, tert-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hex-3-yne, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-mono(tert-butylperoxy)-hexane, α,α'-bis(tert-butylperoxy-m-isopropyl)benzene, di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneopentanoate, tert-butyl peroxyneopentanoate, dilauroyl peroxide, dioctanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, tert-butyl peroxyisobutyrate, 1,1-bis(tert-hexylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxyisopropyl carbonate, 3,5,5-trimethylhexanoyl peroxide, tert-butyl peroxy-2-ethylhexanoate. Examples of commercially available products of the peroxide include products with the trade names "NYPER BMT" series and "NYPER BW" series manufactured by NOF CORPORATION.

[0167] The content of the crosslinking agent in the acrylic adhesive composition can be any appropriate content within the range that does not impair the effects of the present invention. As such a content, for example, in terms of further embodying the effects of the present invention, it is preferably 0.05 parts by weight to 20 parts by weight, more preferably 0.1 parts by weight to 18 parts by weight, still more preferably 0.5 parts by weight to 15 parts by weight, particularly preferably 0.5 parts by weight to 10 parts by weight, relative to the solid content (100 parts by weight) of the acrylic polymer.

[0168] <1-2-c. Polyhydric alcohol>

[0169] The acrylic adhesive composition may contain a polyhydric alcohol. By using a polyhydric alcohol, moderate softness can be imparted to the acrylic adhesive. The polyhydric alcohol may be only one kind or two or more kinds.

[0170] Regarding the number of functional groups of the polyhydric alcohol, in terms of further embodying the effects of the present invention, it is preferably 2 or more, more preferably 3 - 6, still more preferably 3 - 5, particularly preferably 3 - 4, and most preferably 3.

[0171] Examples of the polyhydric alcohol include polyether polyols, polyester polyols, etc.

[0172] Examples of the polyether polyol include: polypropylene glycol (difunctional), diol (difunctional) obtained by adding propylene oxide to bisphenol A, triol (trifunctional) obtained by adding propylene oxide to glycerol, triol (trifunctional) obtained by adding propylene oxide to trimethylolpropane, tetraol (tetrafunctional) obtained by adding propylene oxide to the active hydrogen of ethylenediamine, polyhydric alcohol (polyfunctional) obtained by adding propylene oxide to sorbitol or sucrose, triol (trifunctional) obtained by adding propylene oxide and ethylene oxide to glycerol and having the terminal blocked by ethylene oxide, tetraol (tetrafunctional) obtained by adding propylene oxide and ethylene oxide to the active hydrogen of ethylenediamine and having the terminal blocked by ethylene oxide, polypropylene glycol polyethylene glycol (difunctional) having the terminal blocked by ethylene oxide, diol (difunctional) obtained by adding propylene oxide and ethylene oxide to bisphenol A and having the terminal blocked by ethylene oxide, triol (trifunctional) obtained by adding ethylene oxide to trimethylolpropane, polypropylene glycol polyethylene glycol (difunctional) obtained by randomly adding ethylene oxide and propylene oxide, triol (trifunctional) obtained by randomly adding ethylene oxide and propylene oxide to the triol obtained by adding propylene oxide and ethylene oxide to glycerol, flame - retardant polyol (difunctional), etc.

[0173] Examples of commercially available polyether polyols include ADEKA polyols (e.g., P series, BPX series, G series, T series, EDP series, SP series, SC series, R series, RD series, AM series, BM series, CM series, EM series, GM series, PR series, GR series, flame retardant polyols, etc.) from ADEKA Corporation, and polyols (e.g., SANNIX GP series, SANNIX PP series, SANNIX TP-400 series, SANNIX SP-750 series, SANNIX PL-2100·PP series, SANESTER series, PRIMEPOL series, NEWPOL series, MELPOL series, PEG series, MACROGOL series, etc.) from Sanyo Chemical Industries, Ltd.

[0174] As the polyether polyol, in terms of further demonstrating the effects of the present invention, it is preferably a triol (trifunctional) obtained by adding propylene oxide to glycerol, a triol (trifunctional) obtained by adding propylene oxide to trimethylolpropane, a triol (trifunctional) obtained by adding propylene oxide and ethylene oxide to glycerol and having its terminal blocked by ethylene oxide, a triol (trifunctional) obtained by adding ethylene oxide to trimethylolpropane, a triol (trifunctional) obtained by adding propylene oxide and ethylene oxide to glycerol and having propylene oxide and ethylene oxide randomly added, more preferably a triol (trifunctional) obtained by adding propylene oxide to glycerol, a triol (trifunctional) obtained by adding propylene oxide and ethylene oxide to glycerol and having its terminal blocked by ethylene oxide, a triol (trifunctional) obtained by adding propylene oxide and ethylene oxide to glycerol and having propylene oxide and ethylene oxide randomly added, and even more preferably a triol (trifunctional) obtained by adding propylene oxide to glycerol.

[0175] Examples of polyester polyols include polyester polyols obtained by reacting an acid component with a diol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid, etc. Examples of the diol component include ethylene glycol, propylene glycol, diethylene glycol, butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethyloleptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol. Examples of the polyol component include glycerol, trimethylolpropane, pentaerythritol, etc. As the polyester polyol (a1), there are also polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone.

[0176] Examples of commercially available polyester polyols include ADEKA NEWACE from ADEKA Corporation (e.g., F18-62, F7-67, Y9-10, Y4-5, Y52-13, Y52-21, V14-90, YG-108, F1212-29, #50, Y65-55, YT-101, YT-651, NS-2400, etc.).

[0177] In terms of further demonstrating the effects of the present invention, the number-average molecular weight of the polyol is preferably 50 to 10,000, more preferably 60 to 5,000.

[0178] The content of the polyol in the acrylic adhesive composition can be any appropriate content within the range that does not impair the effects of the present invention. As such a content, for example, in terms of further demonstrating the effects of the present invention, it is preferably 0.0001 parts by weight to 20 parts by weight, more preferably 0.001 parts by weight to 15 parts by weight, further preferably 0.01 parts by weight to 10 parts by weight, and particularly preferably 0.1 parts by weight to 5 parts by weight relative to the solid content (100 parts by weight) of the acrylic polymer.

[0179] <1-2-d. Other Components>

[0180] The acrylic adhesive composition can contain any appropriate other components within the range that does not impair the effects of the present invention. Examples of such other components include: polymer components other than acrylic polymers, crosslinking promoters, crosslinking catalysts, silane coupling agents, adhesion-imparting resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), anti-aging agents, inorganic fillers, organic fillers, metal powders, colorants (pigments, dyes, etc.), foils, ultraviolet absorbers, antioxidants, light stabilizers, nucleating agents, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, conductive agents, stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat stabilizers, polymerization inhibitors, lubricants, solvents, catalysts, etc.

[0181] 《《2. Adherend》》

[0182] As long as the adherend has a water contact angle and an arithmetic mean surface roughness Ra on the surface on the side where the surface protective film is laminated within the above preferred ranges, any appropriate adherend can be used within the range that does not impair the effects of the present invention.

[0183] As described above, the water contact angle of the surface of the surface protective film side (laminated surface protective film side) of the adherend is preferably 85° or more, more preferably 85° to 110°, further preferably 85° to 105°, particularly preferably 90° to 100°, and most preferably 91° to 100°. If the water contact angle is within the above range, the effect of the present invention can be further reflected. If the water contact angle deviates from the above range and is too small, the surface protective film is prone to excessive adhesion to the adherend. For example, the initial peeling force of the surface protective film from the adherend is increased, and the surface protective film may not be peeled off from the adherend. The peeling force of the surface protective film from the adherend increases excessively over time, and the surface protective film may not be peeled off from the adherend. If the water contact angle deviates from the above range and is too large, the surface protective film is not easy to be excessively adhered to the adherend. For example, the initial peeling force of the surface protective film from the adherend is too low, and the surface protective film may be lifted from the adherend; when the release liner that can be provided on the outermost surface is peeled off, the surface protective film may be poorly peeled off.

[0184] As described above, the arithmetic mean surface roughness Ra of the surface on the surface protective film side (laminated surface protective film side) of the adherend is preferably 0.6 μm or less, more preferably 0.35 μm or less, further preferably 0.2 μm or less, particularly preferably 0.1 μm or less, and most preferably 0.08 μm or less. The lower limit of the arithmetic mean surface roughness Ra is as small as possible, preferably 0 μm or more. If the arithmetic mean surface roughness Ra is within the above range, the effect of the present invention can be further reflected. If the arithmetic mean surface roughness Ra deviates from the above range and is too large, for example, when the thickness of the adhesive layer possessed by the surface protective film is large, the peeling force of the surface protective film from the adherend increases excessively over time, and the surface protective film may not be peeled off from the adherend.

[0185] The adherend is typically an optical component. As an optical component, any appropriate optical component can be used within the scope of not damaging the effect of the present invention. As such an optical component, for example, a component having any appropriate layer on any appropriate substrate can be listed. As a specific optical component, for example, a polarizing plate, a phase difference plate, a display, a camera, a lens, a (half) mirror, etc. can be listed.

[0186] It should be noted that as the adherend, any adherend having a water contact angle on one side of the laminated surface protective film and an arithmetic mean surface roughness Ra on one side of the laminated surface protective film falling within the above-mentioned preferred ranges may be selected, and any appropriate material may be used as the material of the surface. However, in order to further embody the effect of the present invention, such a material may be representatively a resin, and as the adherend, a member having any appropriate resin layer may be preferably listed.

[0187] The thickness of the adherend can be any appropriate thickness according to its type. Typically, the thickness of the adherend is preferably 5 μm to 950 μm, more preferably 20 μm to 750 μm, still more preferably 30 μm to 550 μm, and particularly preferably 40 μm to 450 μm.

[0188] Examples

[0189] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by any of these examples. It should be noted that the test and evaluation methods in the examples are as described below. It should be noted that when "parts" are described, it means "parts by weight" unless otherwise specified, and when "%" is described, it means "weight %" unless otherwise specified.

[0190] <Measurement of water contact angle>

[0191] Add 2 μL of water dropwise onto the surface of the adherend on the side of the surface protective film (the side where the surface protective film is laminated), and determine the water contact angle [°] 0.5 seconds after the dropwise addition. The water contact angle is measured using a commercially available contact angle measuring device in accordance with JIS R 3257:1999 (drop method). Specifically, the measurement is carried out under the following conditions. The measurement is carried out 5 times, and the average value thereof is adopted (n = 5).

[0192] [Water contact angle measurement conditions]

[0193] Measuring device: Contact angle meter DropMaster DM700 (manufactured by Kyowa Interface Science Co., Ltd.).

[0194] Measurement atmosphere: 23 °C, 50% RH.

[0195] Measuring liquid: Distilled water.

[0196] Measurement time: After 500 ms of landing.

[0197] <Measurement of arithmetic mean surface roughness Ra>

[0198] Measure the arithmetic mean surface roughness Ra of the surface of the adherend on the side of the surface protective film (the side where the surface protective film is laminated). Specifically, the measurement is carried out under the following conditions.

[0199] [Measurement conditions for arithmetic mean surface roughness Ra]

[0200] Measuring device: High-precision micro shape measuring machine SURFCORDER ET4000A (manufactured by Kosaka Laboratory Ltd.).

[0201] Stylus of the detection part: Tip curvature radius 0.5 μm, apex angle 60 degrees, material diamond.

[0202] Reference length (cut-off value λc of roughness curve): 0.8 mm.

[0203] Evaluation length (reference length): 12 mm.

[0204] Feed speed of the stylus: 1 mm / s.

[0205] Longitudinal magnification: 20,000 times.

[0206] Transverse magnification: 10 times.

[0207] <Evaluation of deformation>

[0208] As Figure 2 shown, a test piece cut to a length of 60 mm and a width of 60 mm from the laminate 1000 (adherend with a surface protective film) obtained in the examples and comparative examples is placed on the upper surface of a test plate 2000 having a recess with dimensions of 25 mm in length, 25 mm in width, and 1 mm in depth formed on the upper surface. In this state, a rod 3000 with a radius R = 8 mm is pressed 1 mm from the upper surface (surface protective film side) of the laminate 1000 to the bottom surface at the center of the recess of the test plate 2000, and after maintaining this state for 1.0 second and then moving the rod away from the laminate 1000, it is confirmed whether a pressing mark remains on the laminate 1000.

[0209] (Evaluation)

[0210] None (〇): No pressing mark remains.

[0211] Yes (×): A pressing mark remains.

[0212] <Initial peel strength (A)>

[0213] Regarding the laminates (adherends with surface protective films) obtained in the examples and comparative examples, after manufacturing, they are left standing for 30 minutes in an environment of a temperature of 23 °C and a relative humidity of 50%, and then, in the same environment, a peel test is carried out at a peel angle of 180° and a tensile speed of 300 mm / minute, and the 180° peel strength is measured and taken as the initial peel strength.

[0214] It should be noted that in the laminate according to the embodiment of the present invention, considering the aspect of further embodying the effects of the present invention, the initial peel force (A) is preferably 0.025 N / 25 mm or more and less than 0.100 N / 25 mm, more preferably 0.030 N / 25 mm or more and less than 0.090 N / 25 mm, further preferably 0.035 N / 25 mm or more and less than 0.085 N / 25 mm, further preferably 0.040 N / 25 mm or more and less than 0.085 N / 25 mm, further preferably 0.040 N / 25 mm or more and less than 0.080 N / 25 mm, particularly preferably 0.040 N / 25 mm or more and less than 0.075 N / 25 mm, and most preferably 0.040 N / 25 mm or more and less than 0.070 N / 25 mm.

[0215] The evaluation criteria are as described below.

[0216] (Evaluation Criteria)

[0217] ◎: 0.040 N / 25 mm or more and less than 0.085 N / 25 mm.

[0218] 〇: 0.030 N / 25 mm or more and less than 0.040 N / 25 mm or 0.085 N / 25 mm or more and less than 0.090 N / 25 mm.

[0219] △: 0.025 N / 25 mm or more and less than 0.030 N / 25 mm or 0.090 N / 25 mm or more and less than 0.100 N / 25 mm.

[0220] ×: Less than 0.025 N / 25 mm or 0.100 N / 25 mm or more.

[0221] <Peel Force (B) after Storage at 60 °C for 72 Hours>

[0222] Regarding the laminates (adherends with surface protective films) obtained in the examples and comparative examples, after manufacturing, they are stored in an environment at a temperature of 60 °C for 72 hours, and then, after standing for 30 minutes in an environment at a temperature of 23 °C and a relative humidity of 50%, in the same environment, a peel test is carried out at a peel angle of 180° and a tensile speed of 300 mm / minute, and the 180° peel force is measured and used as the peel force after storage at 60 °C for 72 hours.

[0223] It should be noted that in the laminate of the embodiment of the present invention, considering the aspect of further embodying the effects of the present invention, the peel strength (B) after storage at 60°C for 72 hours is preferably 0.030 N / 25 mm or more and less than 0.115 N / 25 mm, more preferably 0.040 N / 25 mm or more and less than 0.105 N / 25 mm, further preferably 0.040 N / 25 mm or more and less than 0.100 N / 25 mm, further preferably 0.045 N / 25 mm or more and less than 0.095 N / 25 mm, further preferably 0.050 N / 25 mm or more and less than 0.095 N / 25 mm, particularly preferably 0.055 N / 25 mm or more and less than 0.095 N / 25 mm, and most preferably 0.055 N / 25 mm or more and less than 0.092 N / 25 mm.

[0224] The evaluation criteria are as described below.

[0225] (Evaluation Criteria)

[0226] ◎: 0.055 N / 25 mm or more and less than 0.095 N / 25 mm.

[0227] 〇: 0.040 N / 25 mm or more and less than 0.055 N / 25 mm or 0.095 N / 25 mm or more and less than 0.100 N / 25 mm.

[0228] △: 0.030 N / 25 mm or more and less than 0.040 N / 25 mm or 0.100 N / 25 mm or more and less than 0.115 N / 25 mm.

[0229] ×: Less than 0.030 N / 25 mm or 0.115 N / 25 mm or more.

[0230] <Peel Strength Change (B) - (A)>

[0231] In the laminate of the embodiment of the present invention, considering the aspect of further embodying the effects of the present invention, the smaller the peel strength change (B) - (A), the more preferable it is. It is preferably less than 0.045 N / 25 mm, more preferably less than 0.042 N / 25 mm, further preferably less than 0.040 N / 25 mm, further preferably less than 0.037 N / 25 mm, further preferably less than 0.035 N / 25 mm, particularly preferably less than 0.032 N / 25 mm, and most preferably less than 0.030 N / 25 mm.

[0232] The evaluation criteria are as described below.

[0233] (Evaluation Criteria)

[0234] ◎: Less than 0.035 N / 25 mm.

[0235] 〇: Above 0.035 N / 25 mm and less than 0.042 N / 25 mm.

[0236] △: Above 0.042 N / 25 mm and less than 0.045 N / 25 mm.

[0237] ×: Above 0.045 N / 25 mm.

[0238] <Creep recovery value of the adhesive layer>

[0239] Take out only the adhesive layer from the laminate, laminate it to make a thickness of about 1 mm, punch it into a φ8 mm circle, make cylindrical particles, and use them as measurement samples.

[0240] Using a dynamic viscoelasticity measuring device (manufactured by TA Instruments, DHR2), fix the obtained measurement sample to a φ8 mm parallel plate jig. At 25 °C, set the strain (%) after applying a deformation stress of 5 KPa and maintaining it for 300 seconds as the A value, and further set the strain (%) after setting the deformation stress to 0 and maintaining it for 300 seconds as the B value. The value calculated by [{(A value - B value) / A value} × 100] is used as the creep recovery value.

[0241] <Shear modulus>

[0242] Cut out the surface protective film used in the laminates obtained in the examples and comparative examples to 5 mm (TD) × 50 mm (MD). Use an acrylic plate (manufactured by MITSUBISHI CHEMICAL, trade name "Acrylite L") as the adherend, and bond the adhesive layer of the surface protective film in a manner that the contact area is 5 mm × 10 mm. Then, after leaving it to stand for 30 minutes in an environment of temperature 23 °C and relative humidity 50%, in the same environment, use a precision universal testing machine (manufactured by Shimadzu Corporation, AUTOGRAPH AG-X plus) to measure the shear stress in the shear direction at a tensile speed of 0.06 mm / min, and obtain a shear strain (horizontal axis) - shear stress (vertical axis) curve.

[0243] The shear modulus G is calculated as the slope from a shear strain of 0.05 mm to 0.2 mm by the following formula.

[0244] G = τ / γ = (τ 0.2 - τ 0.05 ) / (0.2 - 0.05)

[0245] τ: Shear stress [N / 50 mm 2

[0246] γ: Shear strain [mm]

[0247] τ 0.2 : Shear stress at a shear strain of 0.2 mm [N / 50 mm 2

[0248] τ 0.05 : Shear stress at a shear strain of 0.05 mm [N / 50 mm 2

[0249] [Production Example 1]: Production of acrylic polymer (1)

[0250] Into a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen inlet tube, 96.2 parts by weight of 2-ethylhexyl acrylate (2EHA), 3.8 parts by weight of 2-hydroxyethyl acrylate (HEA) as monomer components, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 150 parts by weight of ethyl acetate were charged together. While slowly stirring at 23°C, nitrogen was introduced for nitrogen replacement. Then, the liquid temperature was maintained at around 65°C, and a polymerization reaction was carried out for 6 hours to produce a solution (concentration 40% by weight) of acrylic polymer (1). The weight-average molecular weight of acrylic polymer (1) was 540,000.

[0251] In addition, when calculated by the FOX formula, the Tg of acrylic polymer (1) was (-70°C × 0.962) + (-15°C × 0.038) = (-67.34°C) + (-0.57°C) = -67.91°C.

[0252] [Production Example 2]: Production of acrylic polymer (2)

[0253] Into a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen inlet tube, 100.0 parts by weight of 2-ethylhexyl acrylate (2EHA), 80 parts by weight of vinyl acetate (VAc), 5.0 parts by weight of acrylic acid (AA) as monomer components, 0.3 parts by weight of benzoyl peroxide (BPO, manufactured by NOF Corporation, "NYPER (registered trademark) BW") as a polymerization initiator, and 263 parts by weight of toluene were charged together. While slowly stirring at 23°C, nitrogen was introduced for nitrogen replacement. Then, the liquid temperature was maintained at around 63°C, and a polymerization reaction was carried out for 6 hours. Then, the temperature of the contents of the container was raised to 80°C, and aging was carried out for 3.5 hours to produce a solution (concentration 40% by weight) of acrylic polymer (2). The weight-average molecular weight of acrylic polymer (2) was 650,000.

[0254] ​​In addition, when the Tg of the acrylic polymer (2) is calculated by the FOX formula, it is (−70°C × 0.541) + (30°C × 0.432) + (106°C × 0.027) = (−37.87°C) + (12.96°C) + (2.86°C) = −22.05°C.

[0255] [Production Example 3]: Production of acrylic polymer (3)

[0256] After carrying out the polymerization reaction for 6 hours without aging, the rest was carried out in the same manner as in Production Example 2 to produce a solution (concentration 40% by weight) of acrylic polymer (3). The weight-average molecular weight of acrylic polymer (3) was 810,000.

[0257] [Production Example 4]: Production of acrylic polymer (4)

[0258] The aging time was changed from 3.5 hours to 2 hours, and the rest was carried out in the same manner as in Production Example 2 to produce a solution (concentration 40% by weight) of acrylic polymer (4). The weight-average molecular weight of acrylic polymer (4) was 710,000.

[0259] [Production Example 5]: Production of acrylic polymer (5)

[0260] The aging time was changed from 3.5 hours to 7 hours, and the rest was carried out in the same manner as in Production Example 2 to produce a solution (concentration 40% by weight) of acrylic polymer (5). The weight-average molecular weight of acrylic polymer (5) was 460,000.

[0261] [Production Example 6]: Production of acrylic adhesive composition (1)

[0262] To 100 parts by weight of the solid content of the solution of acrylic polymer (1) obtained in Production Example 1, 0.5 part by weight of SANNIX PP-3000 (manufactured by Sanyo Chemical Industries, Ltd.) as an additive and 3.0 parts by weight of TAKENATE D-101E (manufactured by Mitsui Chemicals, Inc.) as a crosslinking agent were added in terms of solid content, and it was diluted with toluene so that the total solid content became 29% by weight, and stirred with a disperser to produce acrylic adhesive composition (1).

[0263] [Production Example 7]: Production of acrylic adhesive composition (2)

[0264] To 100 parts by weight of the solid content of the acrylic polymer (2) solution obtained in Production Example 2, 4.0 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a crosslinking agent in terms of solid content was added, diluted with methyl ethyl ketone so that the total solid content became 22% by weight, and stirred with a disperser to produce an acrylic adhesive composition (2).

[0265] [Production Example 8]: Production of acrylic adhesive composition (3)

[0266] To 100 parts by weight of the solid content of the acrylic polymer (3) solution obtained in Production Example 3, 4.0 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a crosslinking agent in terms of solid content was added, diluted with methyl ethyl ketone so that the total solid content became 22% by weight, and stirred with a disperser to produce an acrylic adhesive composition (3).

[0267] [Production Example 9]: Production of acrylic adhesive composition (4)

[0268] To 100 parts by weight of the solid content of the acrylic polymer (4) solution obtained in Production Example 4, 4.0 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a crosslinking agent in terms of solid content was added, diluted with methyl ethyl ketone so that the total solid content became 22% by weight, and stirred with a disperser to produce an acrylic adhesive composition (4).

[0269] [Production Example 10]: Production of acrylic adhesive composition (5)

[0270] To 100 parts by weight of the solid content of the acrylic polymer (5) solution obtained in Production Example 5, 4.0 parts by weight of TETRAD-C (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a crosslinking agent in terms of solid content was added, diluted with methyl ethyl ketone so that the total solid content became 22% by weight, and stirred with a disperser to produce an acrylic adhesive composition (5).

[0271] [Production Example 11]: Production of surface protective film (1)

[0272] The acrylic adhesive composition (1) obtained in Production Example 6 of corona surface coating of a biaxially stretched polyester film (“T100C38” manufactured by MITSUBISHI CHEMICAL, thickness 38 μm) was heated at 130°C for 2 minutes to form an adhesive layer with a thickness of 21 μm. The release-treated surface of a release liner (a polyester film with a thickness of 25 μm that has been silicone release-treated on one side) was adhered to the surface of the adhesive layer to produce a surface protective film (1) with a release liner.

[0273] [Production Example 12]: Production of Surface Protective Film (2)

[0274] The acrylic adhesive composition (2) obtained in Production Example 7 of corona surface coating of a biaxially stretched polyester film (“T100C38” manufactured by MITSUBISHI CHEMICAL, thickness 38 μm) was heated at 130°C for 2 minutes to form an adhesive layer with a thickness of 21 μm. The release-treated surface of a release liner (a polyester film with a thickness of 25 μm that has been silicone release-treated on one side) was adhered to the surface of the adhesive layer to produce a surface protective film (2) with a release liner.

[0275] [Production Example 13]: Production of Surface Protective Film (3)

[0276] The acrylic adhesive composition (3) obtained in Production Example 8 of corona surface coating of a biaxially stretched polyester film (“T100C38” manufactured by MITSUBISHI CHEMICAL, thickness 38 μm) was heated at 130°C for 2 minutes to form an adhesive layer with a thickness of 10 μm. The release-treated surface of a release liner (a polyester film with a thickness of 25 μm that has been silicone release-treated on one side) was adhered to the surface of the adhesive layer to produce a surface protective film (3) with a release liner.

[0277] [Production Example 14]: Production of Surface Protective Film (4)

[0278] The acrylic adhesive composition (4) obtained in Production Example 9 of corona surface coating of a biaxially stretched polyester film (“T100C38” manufactured by MITSUBISHI CHEMICAL, thickness 38 μm) was heated at 130°C for 2 minutes to form an adhesive layer with a thickness of 10 μm. The release-treated surface of a release liner (a polyester film with a thickness of 25 μm that has been silicone release-treated on one side) was adhered to the surface of the adhesive layer to produce a surface protective film (4) with a release liner.

[0279] [Production Example 15]: Production of Surface Protective Film (5)

[0280] The acrylic adhesive composition (5) obtained in Production Example 10 of corona surface coating of a biaxially stretched polyester film (MITSUBISHI CHEMICAL's "T100C38", thickness 38 μm) was heated at 130 °C for 2 minutes to form an adhesive layer with a thickness of 10 μm. The release-treated surface of a release liner (a polyester film with a thickness of 25 μm and one-sided silicone release treatment) was adhered to the surface of the adhesive layer to produce a surface protective film (5) with a release liner.

[0281] [Production Example 16]: Production of Coating Liquid (1)

[0282] Prepare 50 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "UA53H-80MB", solid content 80%) and 50 parts by weight of a polyfunctional acrylate mainly composed of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100%). These resins were mixed with 0.5 parts by weight of copolymer particles of acrylic acid and styrene (manufactured by Sekisui Chemical Co., Ltd., trade name "TECHPOLYMER SSX1055QXE") as particles per 100 parts by weight of the total resin solid content of these resins, 1.5 parts by weight of synthetic montmorillonite as an organic clay as a tackifier (manufactured by Kunimine Industries Co., Ltd., trade name "SUMECTON SAN"), 5 parts by weight of a photoinitiator (manufactured by BASF Co., Ltd., trade name "OMNIRAD 907"), and 0.1 part by weight of a leveling agent (manufactured by DIC Corporation, trade name "GRANDIC PC4100", solid content 10%). The mixture was diluted with a toluene / cyclopentanone mixed solvent (70 / 30) so that the solid content concentration became 40% to produce coating liquid (1).

[0283] [Production Example 17]: Production of Coating Liquid (2)

[0284] In Production Example 16, the leveling agent (manufactured by DIC Corporation, trade name "GRANDIC PC4100", solid content 10%) was changed to "KY-1203" (solid content 20%) manufactured by Shin-Etsu Chemical Co., Ltd., and otherwise, it was carried out in the same manner as in Production Example 16 to produce coating liquid (2).

[0285] [Production Example 18]: Production of Coating Liquid (3)

[0286] In Production Example 16, the amount of the copolymer particles of acrylic acid and styrene (manufactured by Sekisui Chemical Co., Ltd., trade name “TECHPOLYMER SSX1055QXE”) used was changed from 0.5 parts by weight to 3.0 parts by weight, and other than this, the production was carried out in the same manner as in Production Example 16 to produce the coating liquid (3).

[0287] [Production Example 19]: Production of Coating Liquid (4)

[0288] In Production Example 16, the amount of the leveling agent (manufactured by DIC Corporation, trade name “GRANDIC PC4100”, solid content 10%) used was changed from 0.1 parts by weight to 0.01 parts by weight, and other than this, the production was carried out in the same manner as in Production Example 16 to produce the coating liquid (4).

[0289] [Production Example 20]: Production of Coating Liquid (5)

[0290] In Production Example 16, the amount of the leveling agent (manufactured by DIC Corporation, trade name “GRANDIC PC4100”, solid content 10%) used was changed from 0.1 parts by weight to 0.05 parts by weight, and other than this, the production was carried out in the same manner as in Production Example 16 to produce the coating liquid (5).

[0291] [Production Example 21]: Production of Coating Liquid (6)

[0292] In Production Example 16, the amount of the leveling agent (manufactured by DIC Corporation, trade name “GRANDIC PC4100”, solid content 10%) used was changed from 0.1 parts by weight to 0.15 parts by weight, and other than this, the production was carried out in the same manner as in Production Example 16 to produce the coating liquid (6).

[0293] [Production Example 22]: Production of Adherend (1)

[0294] A biaxially stretched polyester film (manufactured by Mitsubishi Chemical Corporation, trade name “T100C#38”) was prepared as the base material.

[0295] The coating liquid (1) produced in Production Example 16 was applied to the corona-treated surface of the base material using a wire bar to form an undried coating film. Then, the base material having the undried coating film formed thereon was heated at 100°C for 1 minute, whereby the undried coating film was dried. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the coating film, and an adherend (1) having a coating film thickness of 5 μm was produced.

[0296] [Production Example 23]: Production of Adherend (2)

[0297] Prepare a biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name "T100C#38") as the base material.

[0298] Using a wire bar, apply the coating liquid (2) produced in Production Example 17 to the corona-treated surface of the base material to form an undried coating film. Then, heat the base material with the undried coating film formed thereon at 100°C for 1 minute to dry the undried coating film. Then, irradiate ultraviolet rays with an accumulated light amount of 300 mJ / cm 2 to cure the coating film, and produce an adherend (2) with a coating film thickness of 5 μm.

[0299] [Production Example 24]: Production of adherend (3)

[0300] Prepare a biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name "T100C#38") as the base material.

[0301] Using a wire bar, apply the coating liquid (1) produced in Production Example 16 to the corona-treated surface of the base material to form an undried coating film. Then, heat the base material with the undried coating film formed thereon at 100°C for 1 minute to dry the undried coating film. Then, irradiate ultraviolet rays with an accumulated light amount of 300 mJ / cm 2 to cure the coating film, and produce an adherend (3) with a coating film thickness of 3 μm.

[0302] [Production Example 25]: Production of adherend (4)

[0303] Prepare a biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name "T100C#38") as the base material.

[0304] Using a wire bar, apply the coating liquid (3) produced in Production Example 18 to the corona-treated surface of the base material to form an undried coating film. Then, heat the base material with the undried coating film formed thereon at 100°C for 1 minute to dry the undried coating film. Then, irradiate ultraviolet rays with an accumulated light amount of 300 mJ / cm 2 to cure the coating film, and produce an adherend (4) with a coating film thickness of 3 μm.

[0305] [Production Example 26]: Production of adherend (5)

[0306] Prepare a biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name "T100C#38") as the base material.

[0307] Using a wire bar, the coating liquid (4) produced in Production Example 19 was applied to the corona surface of the substrate to form an undried coating film. Then, the substrate having the undried coating film formed thereon was heated at 100°C for 1 minute, thereby drying the undried coating film. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the coating film, and an adherend (5) with a coating film thickness of 5 μm was produced.

[0308] [Production Example 27]: Production of adherend (6)

[0309] A biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name “T100C#38”) was prepared as the substrate.

[0310] Using a wire bar, the coating liquid (5) produced in Production Example 20 was applied to the corona surface of the substrate to form an undried coating film. Then, the substrate having the undried coating film formed thereon was heated at 100°C for 1 minute, thereby drying the undried coating film. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the coating film, and an adherend (6) with a coating film thickness of 5 μm was obtained.

[0311] [Production Example 28]: Production of adherend (7)

[0312] A biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name “T100C#38”) was prepared as the substrate.

[0313] Using a wire bar, the coating liquid (6) produced in Production Example 21 was applied to the corona surface of the substrate to form an undried coating film. Then, the substrate having the undried coating film formed thereon was heated at 100°C for 1 minute, thereby drying the undried coating film. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the coating film, and an adherend (7) with a coating film thickness of 5 μm was obtained.

[0314] [Production Example 29]: Production of adherend (8)

[0315] A biaxially stretched polyester film (manufactured by MITSUBISHI CHEMICAL Corporation, trade name “T100C#38”) was prepared as the substrate.

[0316] Using a wire bar, the coating liquid (1) produced in Production Example 16 was applied to the corona surface of the substrate to form an undried coating film. Then, the substrate having the undried coating film formed thereon was heated at 100°C for 1 minute, thereby drying the undried coating film. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm2 The ultraviolet rays were used to cure the coating film, and the adherend (8) with a coating film thickness of 4.5 μm was obtained.

[0317] [Example 1]: Manufacture of the laminate (1)

[0318] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (1) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, and the laminate (1) was obtained.

[0319] The results are shown in Table 1.

[0320] [Example 2]: Manufacture of the laminate (2)

[0321] The surface protective film (2) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (1) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, and the laminate (2) was obtained.

[0322] The results are shown in Table 1.

[0323] [Example 3]: Manufacture of the laminate (3)

[0324] The surface protective film (3) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (1) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, and the laminate (3) was obtained.

[0325] The results are shown in Table 1.

[0326] [Example 4]: Manufacture of the laminate (4)

[0327] The surface protective film (4) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (1) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, and the laminate (4) was obtained.

[0328] The results are shown in Table 1.

[0329] [Example 5]: Manufacture of the laminate (5)

[0330] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (2) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute to obtain a laminate (5).

[0331] The results are shown in Table 1.

[0332] [Example 6]: Manufacture of laminate (6)

[0333] The surface protective film (4) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (2) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute to obtain a laminate (6).

[0334] The results are shown in Table 1.

[0335] [Example 7]: Manufacture of laminate (7)

[0336] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (3) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute to obtain a laminate (7).

[0337] The results are shown in Table 1.

[0338] [Example 8]: Manufacture of laminate (8)

[0339] The surface protective film (4) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (3) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute to obtain a laminate (8).

[0340] The results are shown in Table 1.

[0341] [Example 9]: Manufacture of laminate (9)

[0342] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (6) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute to obtain a laminate (9).

[0343] The results are shown in Table 1.

[0344] [Example 10]: Manufacturing of the laminate (10)

[0345] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (7) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, obtaining the laminate (10).

[0346] The results are shown in Table 1.

[0347] [Example 11]: Manufacturing of the laminate (11)

[0348] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (8) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, obtaining the laminate (11).

[0349] The results are shown in Table 1.

[0350] [Comparative Example 1]: Manufacturing of the laminate (C1)

[0351] The surface protective film (5) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (1) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, obtaining the laminate (C1).

[0352] The results are shown in Table 1.

[0353] [Comparative Example 2]: Manufacturing of the laminate (C2)

[0354] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (4) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feed rate of 0.3 m / minute, obtaining the laminate (C2).

[0355] The results are shown in Table 1.

[0356] [Comparative Example 3]: Manufacturing of the laminate (C3)

[0357] The surface protective film (1) with a release liner was cut into a size of 25 mm in width and 100 mm in length. After peeling off the release liner, it was roll-pressed onto the adherend (5) cut into a size of 70 mm in width and 100 mm in length at a pressure of 0.25 MPa and a feeding speed of 0.3 m / minute to obtain a laminate (C3).

[0358] The results are shown in Table 1.

[0359] [Table 1]

[0360]

[0361] Industrial applicability

[0362] The laminate of the present invention can be used for any suitable purpose. Preferably, the laminate of the present invention is preferably used in the fields of optical components and electronic components.

Claims

1. A laminate, wherein, Comprising a surface protective film and an adherend, The surface protective film has a substrate and an adhesive layer, The adhesive layer is directly laminated with the adherend, The water contact angle of the surface of the adherend on the surface protective film side is 85° or more, The arithmetic mean surface roughness Ra of the surface of the adherend on the surface protective film side is 0.6 μm or less, The creep recovery value of the adhesive layer is 96% or more.

2. A laminate, wherein, Comprising a surface protective film and an adherend, The surface protective film has a substrate and an adhesive layer, The adhesive layer is directly laminated with the adherend, The water contact angle of the surface of the adherend on the surface protective film side is 85° or more, The arithmetic mean surface roughness Ra of the surface of the adherend on the surface protective film side is 0.6 μm or less, The shear modulus G of the surface protective film is 39.0 N / 50 mm 3 as follows.

3. The laminate according to claim 1 or 2, wherein, The water contact angle is 85° to 105°.

4. The laminate according to claim 1 or 2, wherein, The arithmetic mean surface roughness Ra is 0.1 μm or less.

5. The laminate according to claim 1, wherein, The creep recovery value is 99% or more.

6. The laminate according to claim 2, wherein, The shear modulus G is 30.0 N / 50 mm 3 as follows.

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