Antistatic film and protective film

Abstract

[Problem] To provide an antistatic film in which an antistatic layer laminated on the opposite surface of an adhesive layer of a protective film has good releasability from a laminating roll, and a protective film. [Means for solving the problem] A laminated polyester film is a laminated polyester film having an antistatic layer on at least one surface of a base material, the antistatic layer being a layer obtained by curing a composition containing a conductive polymer, a crosslinking agent (A), and a binder resin (B) having at least one reactive group, the antistatic layer satisfying (1) to (3) below: (1) surface resistivity: 3 [logΩ / □] or more and 9 [logΩ / □] or less; (2) static contact angle of water: 70 to 95°; and (3) adhesion energy of water: 3.5 mJ / m 2 The following.

Description

Technical Field

[0001] The present invention relates to a laminated polyester film and a protective film formed by laminating an adhesive layer on the laminated polyester film, and particularly to a protective film for optical members (for example, components of organic EL and liquid crystal displays). Background Art

[0002] The film formed by laminating an adhesive layer on a base film is used as a protective film for each component in the manufacturing process of an optical component, etc. The protective film is attached to each component as an adherend by means of an adhesive layer, and plays a role in suppressing scratches and dirt adhesion during the processing and transportation of each component. As the base film used in these protective films, an antistatic film having an antistatic layer laminated on at least one side is used. The purpose of laminating the antistatic layer is to prevent foreign matter such as garbage and dust from adhering to the protective film and to suppress the static electricity generated when the protective film is peeled off from the adherend (see patent document 1).

[0003] As an antistatic film, an antistatic film containing PEDOT:PSS as an antistatic agent has been proposed (see Patent Document 2).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 012545

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-172473 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] Protective films with antistatic layers can be used as protective films for optical components, particularly during the processing of display components. In recent years, they have also been increasingly used in the processing of components for organic EL displays (particularly OLED displays). During the process of laminating the protective film to the optical component, the protective film is positioned so that the adhesive layer of the protective film contacts the optical component. The protective film is then pressed against the optical component using a laminating roller or the like, from the side opposite the adhesive layer.

[0010] When using a laminating roller to apply a protective film using the above method, there is a risk that the interaction between the surface of the protective film opposite the surface laminated with the adhesive layer and the laminating roller will become stronger, thereby reducing the ability of the laminating roller to release the protective film, making it difficult to apply the protective film evenly. In recent years, the adhesion of adhesives has been reduced to prevent deformation when peeling fragile and easily scratched precision components. In such applications, the ability of the laminating roller to release the protective film has become a particular problem.

[0011] The present invention addresses the above-mentioned problems of a protective film and provides an antistatic film and a protective film in which an antistatic layer laminated on the surface of the protective film opposite to the adhesive layer has good releasability from a laminating roll.

[0012] Solutions for solving problems

[0013] That is, the present invention includes the following configurations.

[0014] [1] A laminated polyester film comprising an antistatic layer on at least one surface of a substrate,

[0015] The antistatic layer is a layer formed by curing a composition comprising a conductive polymer, a crosslinking agent (A), and a binder resin (B).

[0016] The binder resin (B) is a long-chain alkyl compound having at least one reactive group.

[0017] The antistatic layer satisfies the following (1)-(3):

[0018] (1) Surface resistivity: 3 [logΩ / □] or more and 9 [logΩ / □] or less;

[0019] (2) Water contact angle: 70° or more and 95° or less;

[0020] (3) Water adhesion energy: 3.5mJ / m 2 the following.

[0021] [2] In one embodiment, the laminated polyester film has a total light transmittance of 80% or more and a haze of 3.0% or less.

[0022] [3] In one embodiment, the haze of the laminated polyester film after heating at 140° C. for 10 minutes is 1.5 times or less of the haze before heating.

[0023] [4] In one embodiment, the change in surface resistivity of the antistatic layer after a wiping test with alcohol is 1.3 times or less of the surface resistivity before the test.

[0024] [5] In one embodiment, the conductive polymer is contained in an amount of 5% by mass or more and 50% by mass or less based on 100% by mass of the total solid content in the antistatic layer.

[0025] [6] In one embodiment, the crosslinking agent (A) and the binder resin (B) are contained in the following ranges relative to 100% by mass of the total solid content in the antistatic layer.

[0026] (A) 15% by mass or more and 75% by mass or less

[0027] (B) 10% by mass or more and 70% by mass or less

[0028] [7] In one embodiment, the hydroxyl value of the binder resin (B) is 20 mgKOH / g or more and 300 mgKOH / g or less.

[0029] [8] In one embodiment, the binder resin (B) contains a carboxyl group.

[0030] [9] In one embodiment, the crosslinking agent comprises at least one selected from acrylamide, melamine resin, carbodiimide, oxazoline, isocyanate, and aziridine.

[0031]

[10] In one embodiment, the laminated polyester film does not substantially contain an organosilicon compound.

[0032]

[11] In one embodiment, a protective film is provided in which an adhesive layer is laminated on at least one surface of the laminated polyester film.

[0033] Here, 100% by mass of the total solid content refers to the total mass % of the conductive polymer, the crosslinking agent (A), and the binder resin (B).

[0034] Effects of the Invention

[0035] According to the present invention, by providing an antistatic film having an antistatic layer with low adhesion energy laminated on at least one side of a polyester film, it is possible to provide a protective film that has good detachability from the laminating roller when laminating the protective film and suppresses peeling charge and foreign matter adhesion during peeling when the laminated polyester film of the present invention is laminated and used as a protective film. DETAILED DESCRIPTION

[0036] The laminated polyester film of the present invention (also sometimes referred to as antistatic film) is a material having an antistatic layer laminated on at least one side of a polyester film. Additionally, an adhesive layer may be laminated on one side of the antistatic film to be used as a protective film.

[0037] For example, when a laminating roller is used when laminating a protective film with the laminated polyester film of the present invention, the interaction between the surface of the protective film opposite to the surface laminated with the adhesive layer and the laminating roller can be suppressed from becoming stronger, thereby preventing a decrease in the releasability of the laminating roller from the protective film. Furthermore, the protective film can be evenly laminated.

[0038] In recent years, in particular, the adhesion of adhesives has sometimes been reduced in order to enable peeling of fragile and easily scratched precision components while suppressing component deformation. Even in such applications, the present invention can maintain good releasability between the laminating roller and the protective film.

[0039] The present invention is described in detail below.

[0040] (Polyester film)

[0041] The polyester film used as the substrate in the present invention is a film primarily composed of a polyester resin. Here, "a film primarily composed of a polyester resin" refers to a film formed from a resin composition containing 50% by mass or more of a polyester resin. When blended with other polymers, this refers to a film containing 50% by mass or more of a polyester resin, and when copolymerized with other monomers, this refers to a film containing 50 mol% or more of repeating polyester units. In the polyester film, the resin composition constituting the film preferably contains 90% by mass or more, more preferably 95% by mass or more, and even more preferably 100% by mass of a polyester resin.

[0042] The polyester resin is not particularly limited in material, and a copolymer formed by polycondensation of a dicarboxylic acid component and a diol component, or a blended resin thereof, can be used. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, diphenyl carboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl sulfone carboxylic acid, anthracene dicarboxylic acid, 1,3-cyclopentane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, and dodecanedicarboxylic acid.

[0043] Examples of the diol component constituting the polyester resin include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-bis(4-hydroxyphenyl)propane, and bis(4-hydroxyphenyl)sulfone.

[0044] The dicarboxylic acid component and the diol component constituting the polyester resin may be used singly or in combination. In addition, other acid components such as trimellitic acid and other hydroxyl components such as trimethylolpropane may be added as appropriate.

[0045] Specific examples of the polyester resin include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among these, polyethylene terephthalate is preferred due to the balance between physical properties and cost.

[0046] To improve the handleability of the polyester film, such as its slipperiness and windability, the film may contain inactive particles. However, for optical applications, the polyester film is preferably substantially particle-free. When the polyester film is particle-free, the coating layer formed by in-line coating preferably contains particles. Particle-free polyester film and particle-containing coating layer are preferred because this improves transparency and facilitates appearance inspection.

[0047] The haze of the polyester film used in the present invention is preferably 3% or less, more preferably 2.5% or less, and can be 2.0% or less. It can be 1.5% or less, further preferably 1.0% or less, and can be 0.8% or less.

[0048] When the content is 3% or less, it is preferable because appearance inspection and the like can be performed in a state where the protective film is bonded to the adherend. This is particularly preferable when the adherend is a member for optical applications.

[0049] The regional average surface roughness (Sa) of the polyester film used in the present invention is preferably in the range of 1 to 40 nm, more preferably 1 to 30 nm. It is further preferably 1 to 10 nm. The maximum protrusion height (P) of the surface of the polyester film used in the present invention is preferably 2 μm or less, more preferably 1.5 μm or less. It is further preferably 0.8 μm or less. When Sa is 40 nm or less and P is 2 μm or less, there is no need to worry about the adhesive surface becoming rough even when the adhesive layers are stacked and wound into a roll, which is preferred.

[0050] In the present invention, the thickness of the polyester film is not particularly limited, but is preferably in the range of 12 to 188 μm. It is more preferably 18 to 125 μm, and even more preferably 25 to 100 μm. A thickness of 12 μm or greater eliminates the risk of wrinkles when attached to an adherend as a protective film, while a thickness of 188 μm or less offers cost advantages.

[0051] The polyester film forming the substrate can be a monolayer or a laminate of two or more layers. In addition, if the effect of the present invention is achieved, various additives can be contained in the film as required. Examples of additives include antioxidants, light stabilizers, anti-gelling agents, organic wetting agents, antistatic agents, ultraviolet light absorbers, surfactants, etc. When the film has a laminated structure, it is also preferred to contain additives according to the function of each layer as required.

[0052] A polyester film is obtained, for example, by melt-extruding the polyester resin into a film form, cooling and solidifying the film on a casting drum. The polyester film of the present invention may be either an unstretched film or a stretched film, but stretched films are preferred from the perspectives of durability such as mechanical strength and chemical resistance. When the polyester film is a stretched film, the stretching method is not particularly limited, and may be longitudinal uniaxial stretching, transverse uniaxial stretching, sequential longitudinal and transverse biaxial stretching, or simultaneous longitudinal and transverse biaxial stretching.

[0053] To improve adhesion with the adhesion-improving layer, the surface layer of the polyester film may be subjected to surface treatment such as anchor coating, corona treatment, plasma treatment, or flame treatment. When providing an anchor coating layer, in-line coating is preferred from the viewpoint of cost.

[0054] (Antistatic layer)

[0055] The laminated polyester film (antistatic film) of the present invention needs to have an antistatic layer laminated on at least one side of the polyester film. The antistatic layer may be laminated on only one side or on both sides. By laminating the antistatic layer, when the adhesive layer is laminated as a protective film, it is also possible to suppress static electricity or foreign matter adhesion when peeling from the adherend, and therefore it is preferred.

[0056] The antistatic layer is a layer formed by curing a composition containing a conductive polymer, a crosslinking agent (A), and a binder resin (B). Such a composition is sometimes referred to as an antistatic layer-forming composition.

[0057] The means for laminating the antistatic layer is not particularly limited, and known methods such as coating, vacuum deposition, and lamination can be used. From the viewpoint of cost, it is more preferable to apply a coating liquid containing an antistatic agent by coating.

[0058] (Conductive polymer)

[0059] The conductive polymer used in the present invention is a polymer that imparts antistatic properties. Examples of polymers that utilize ion conduction, such as cationic compounds, and π-electron conjugated conductive polymers can be used. From the perspective of antistatic performance under low humidity, π-electron conjugated conductive polymers are preferred. Furthermore, π-electron conjugated conductive polymers can maintain high levels of antistatic performance independent of atmospheric moisture, thus exhibiting excellent antistatic performance in various environments in which the protective film is used.

[0060] In addition, an antistatic agent may be used in combination within a range that does not impair the effects of the conductive polymer of the present invention. The antistatic agent may be a polymer utilizing ion conduction, such as a cationic compound other than the conductive polymer of the present invention, or a conductive polymer having a π-electron conjugated system, and surfactants, silicon oxide compounds, conductive metal compounds, etc. may be used.

[0061] As the π-electron conjugated conductive polymer, there can be mentioned aniline-based polymers comprising aniline or its derivatives as structural units, pyrrole-based polymers comprising pyrrole or its derivatives as structural units, acetylene-based polymers comprising acetylene or its derivatives as structural units, thiophene-based polymers comprising thiophene or its derivatives as structural units, etc. If high transparency is desired, it is preferred that the π-electron conjugated conductive polymer does not have nitrogen atoms. Among them, from the viewpoint of transparency, thiophene-based polymers comprising thiophene or its derivatives as structural units are preferred, and polyalkylene dioxythiophene is particularly preferred. As the polyalkylene dioxythiophene, polyethylene dioxythiophene, polypropylene dioxythiophene, poly(ethylene / propylene) dioxythiophene, etc. can be mentioned.

[0062] It should be noted that, in order to improve the antistatic properties of thiophene-based polymers containing thiophene or its derivatives as structural units, a dopant of 0.1 to 500 parts by mass may be added to 100 parts by mass of the polymer containing thiophene or its derivatives as structural units. If the amount is too high, electrons will not be able to move easily, thus causing a problem of reduced antistatic properties. On the contrary, if the amount is too low, there will be a problem of reduced dispersibility in solvents. Examples of such dopants include LiCl, R 1- 30 COOLi(R 1-30 : a saturated hydrocarbon group having 1 to 30 carbon atoms), R 1-30 SO3Li、R 1-30 COONa、R 1-30 SO3Na、R 1- 30 COOK, R 1-30 SO3K, tetraethylammonium, I2, BF3Na, BF4Na, HClO4, CF3SO3H, FeCl3, tetracyanoquinoline (TCNQ), Na2B 10 Cl 10 , phthalocyanine, porphyrin, glutamic acid, alkyl sulfonate, polystyrenesulfonic acid Na (K, Li) salt, styrene·styrenesulfonic acid Na (K, Li) salt copolymer, polystyrenesulfonic acid anion, styrenesulfonic acid·styrenesulfonic acid anion copolymer, etc.

[0063] In the present invention, the conductive polymer contained in the antistatic layer preferably comprises 5% by mass or more, more preferably 10% by mass or more, relative to 100% by mass of the solid content in the antistatic layer. It should be noted that when a π-electron conjugated conductive polymer is used as the antistatic agent, and when the above-mentioned dopant is used, the content of the π-electron conjugated conductive polymer in the antistatic layer specified in this application is the total amount of the conductive polymer and the above-mentioned dopant.

[0064] By containing the antistatic agent in such an amount, good antistatic properties can be imparted.

[0065] In the present invention, the conductive polymer contained in the antistatic layer is preferably 50% by mass or less, and more preferably 30% by mass or less, relative to 100% by mass of the total solids content in the antistatic layer. It should be noted that when a π-electron conjugated conductive polymer is used as the antistatic agent and the aforementioned dopant is used, the content of the π-electron conjugated conductive polymer in the antistatic layer specified in this application is the combined amount of the conductive polymer and the aforementioned dopant.

[0066] By including the antistatic agent in such an amount, the antistatic agent is less likely to interact with the binder resin (B) and the like, and the coating liquid is less likely to aggregate, resulting in fewer defects in the antistatic layer and the ability to maintain high transparency.

[0067] [Binder resin (B)]

[0068] Antistatic layer of the present invention comprises binder resin (B).As binder resin, it is not particularly limited, as specific example, polyester resin, acrylic resin, carbamate resin, polyolefin resin, polyvinyl resin (polyvinyl alcohol etc.), polyalkylene glycol, polyalkylene imine, methylcellulose, hydroxy cellulose, starch etc. can be enumerated.Among these, from the viewpoint of the adhesion with polyester film, preferably use polyester resin, acrylic resin, carbamate resin.From the ease of molecular design, molecular weight design, further preferably use acrylic resin.

[0069] In the binder resin (B), in order to make the detachability of the antistatic layer surface and the laminating roller good, it is preferred to have a component that can reduce the adhesion energy of the antistatic layer surface. As this component, it is preferred to have an organosilicon component, a long-chain alkyl component, a fluorine component, etc. When considering the migration to the adherend, the long-chain alkyl component is more preferably used, and the binder resin (B) is a long-chain alkyl compound. Preferably, as described later, the binder resin (B) is a long-chain alkyl compound having at least one reactive group.

[0070] By including a long-chain alkyl compound-containing layer, such as the laminated polyester film of the present application, in the case of using a laminating roll when laminating a protective film, the interaction between the opposite surface of the protective film to the adhesive layer and the laminating roll can be inhibited from becoming strong, and the protective film can be prevented from being detached from the laminating roll. Furthermore, the laminating of the protective film can be performed uniformly.

[0071] In particular, in recent years, for precision members that are fragile and easily scratched, in order to be able to be peeled off while suppressing deformation of the member, the adhesion of the adhesive is sometimes reduced, but even in such uses, the present application can maintain the detachability of the laminating roll from the protective film.

[0072] The binder resin (B) preferably has at least one reactive group. Although not particularly limited, the binder resin (B) preferably has a hydroxyl group, a carboxyl group, an amino group, an acrylate group, an epoxy group, or the like, and more preferably has a hydroxyl group, a carboxyl group.

[0073] As the binder resin (B) of the present application, an acrylic resin is preferred. An acrylic resin that contains a long-chain alkyl group and also has at least one reactive functional group is particularly preferred.

[0074] As the acrylic resin, an acrylic resin having a hydroxyl group and a carboxyl group in the molecule is preferred. It is further preferred to contain 15 to 90 mol% of a structural unit having a hydroxyl group in 100 mol% of the total structural units. When the structural unit having a hydroxyl group is 20 mol% or more, the water solubility of the acrylic resin can be maintained at an appropriate level, and is preferred. On the other hand, when it is 90 mol% or less, the proportion of the low adhesion energy component can be maintained at an appropriate level, and is preferred.

[0075] In order to introduce a hydroxyl group into the acrylic resin, a monomer having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and the like, and a ring-opening addition product of γ-butyrolactone, ε-caprolactone, or the like to 2-hydroxyethyl (meth)acrylate can be used as a copolymerization component. Among these, 2-hydroxyethyl (meth)acrylate is preferred from the viewpoint of not hindering water solubility. Note that two or more of these can be used in combination.

[0076] The hydroxyl value of the binder resin (B), for example, an acrylic resin, is preferably 20 mgKOH / g or greater, more preferably 40 mgKOH / g or greater, and even more preferably 70 mgKOH / g or greater, for example, 120 mgKOH / g or greater. When the hydroxyl value of the binder resin (B), for example, an acrylic resin, is 20 mgKOH / g or greater, the acrylic resin has good water solubility, which is preferred. It should be noted that while this hydroxyl value is exemplified for an acrylic resin, the effects described in this specification can also be achieved by having a hydroxyl value within the above range for any resin that can be used in the binder resin (B) of the present invention.

[0077] The hydroxyl value of the binder resin (B), for example, an acrylic resin, is preferably 300 mgKOH / g or less, more preferably 250 mgKOH / g or less, and even more preferably 200 mgKOH / g or less. A hydroxyl value of the binder resin (B), for example, an acrylic resin, of 300 mgKOH / g or less is preferred because the hydroxyl groups of the acrylic resin and antistatic components such as polythiophene do not interact extremely, and the coating liquid is less likely to aggregate.

[0078] The acrylic resin used in the present invention is preferably a resin having a carboxyl group. The presence of a carboxyl group allows the resin to form a crosslinked structure with a crosslinking agent and easily imparts water solubility. Examples include monomers containing a carboxyl group, such as (meth)acrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid; and monomers containing anhydride groups, such as maleic anhydride and itaconic anhydride.

[0079] For example, the binder resin (B) may have a carboxyl group alone or together with the above-mentioned hydroxyl group.

[0080] The monomer having a carboxyl group preferably accounts for 2 mol% or more, more preferably 5 mol% or more, of all structural units of the acrylic resin (100 mol%). A monomer having a carboxyl group preferably accounts for 4 mol% or more, as it facilitates the formation of a cross-linked structure and imparts water solubility in the antistatic layer, which is preferred. The monomer having a carboxyl group preferably accounts for 65 mol% or less, more preferably 50 mol% or less. A monomer having 65 mol% or less preferably accounts for 65 mol% or less, as the Tg of the resulting coating film does not excessively increase relative to the preferred range described below, resulting in good film-forming properties, which is preferred.

[0081] To achieve good water solubility, it is preferable to neutralize the carboxyl groups introduced into the acrylic resin through the copolymerization of acrylic acid and methacrylic acid. Alkaline neutralizing agents include amine compounds such as ammonia, trimethylamine, triethylamine, and dimethylaminoethanol; and inorganic alkaline substances such as potassium hydroxide and sodium hydroxide. Amine compounds are preferred to facilitate volatilization and crosslinking. The neutralization ratio is preferably 30 to 95 mol%, more preferably 40 to 90 mol%. A neutralization ratio of 30 mol% or higher is preferred because the acrylic resin has sufficient water solubility, facilitates dissolution during coating preparation, and eliminates concerns about whitening of the coating film after drying. On the other hand, a neutralization ratio of 95 mol% or lower is preferred because the water solubility is not excessively high, facilitating mixing of alcohols and other substances during coating preparation.

[0082] The acid value of the binder resin (B), for example, an acrylic resin, is preferably 40 mgKOH / g or greater, more preferably 50 mgKOH / g or greater, and even more preferably 60 mgKOH / g or greater. An acrylic resin having an acid value of 40 mgKOH / g or greater is preferred because it increases the number of crosslinking points with the crosslinking agent, resulting in a stronger coating film with a higher crosslinking density.

[0083] In addition, although this acid value is exemplified for acrylic resin, the effects of the present specification can also be exhibited by resins that can be used in the binder resin (B) of the present invention having an acid value within the above range.

[0084] The acid value of the binder resin (B), for example, an acrylic resin, is preferably 400 mgKOH / g or less, more preferably 350 mgKOH / g or less, and even more preferably 300 mgKOH / g or less. An acid value of 400 mgKOH / g or less for acrylic resins is preferred because the carboxyl groups of the acrylic resin do not interact significantly with antistatic agents such as polythiophene, resulting in less aggregation. Aggregation in the coating solution can reduce the uniformity of the antistatic layer, and reduce antistatic properties and transparency. Therefore, the binder resin (B) of the present invention is preferred to avoid such problems.

[0085] The long-chain alkyl group in the binder resin (B) preferably has an alkyl group having 8 to 25 carbon atoms in the side chain of the resin.

[0086] In one embodiment, as the acrylic resin into which a long-chain alkyl group is introduced, an acrylic resin having an alkyl group having a carbon number of 8 to 25 in the side chain of the acrylic resin is preferable, an alkyl group having a carbon number of 12 to 22 is more preferable, and an alkyl group having a carbon number of 16 to 20 is further preferable. In addition, a copolymer in which a long-chain alkyl group having a carbon number of 8 to 20 is partially contained and which has (meth)acrylate as a main repeating unit and in which ester exchange has been performed can also be preferably used. As examples, (meth)acrylate lauryl ester, (meth)acrylate stearyl ester, and the like can be given. Among these, from the viewpoints of easiness of handling, cost, and obtaining a low adhesion energy, the use of (meth)acrylate stearyl ester is preferable.

[0087] The monomer having a long-chain alkyl group among the monomers that are copolymerized is preferably 50 mol% or less, and more preferably 40 mol% or less, in 100 mol% of the total structural units of the binder resin (B), such as the acrylic resin. When it is 50 mol% or less, the adhesion energy of the coating film surface of the antistatic layer can be effectively reduced, and the Tg of the obtained coating film does not excessively decrease from the preferable range, the hardness of the coating film can be maintained high, and thus it is preferable. In the present application, the monomer having a long-chain alkyl group is preferably 5% or more in 100 mol% of the total structural units of the acrylic resin. When it is 5% or more, the adhesion energy of the coating film surface of the antistatic layer can be reduced, and thus it is preferable.

[0088] The glass transition temperature (Tg) of the binder resin (B), such as the acrylic resin, is preferably 50°C or higher, more preferably 55°C or higher, and further preferably 60°C or higher. When the glass transition temperature of the acrylic resin is 50°C or higher, the temporal change of the antistatic layer is suppressed, and thus it is preferable.

[0089] The glass transition temperature (Tg) of the binder resin (B), such as the acrylic resin, is preferably 110°C or lower, more preferably 105°C or lower, and further preferably 100°C or lower. When the glass transition temperature of the acrylic resin is 110°C or lower, the coating film does not excessively become brittle, and cracks and the like are less likely to occur in the antistatic layer, and thus it is preferable.

[0090] As Tg-adjusting monomers copolymerized to adjust the Tg to fall within the above-mentioned range, (meth)acrylic monomers and non-acrylic vinyl monomers can be used. Specific examples of (meth)acrylic monomers include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, and stearyl (meth)acrylate; nitrogen-containing acrylic monomers such as (meth)acrylamide, diacetone acrylamide, N-methylol acrylamide, and (meth)acrylonitrile; and vinyl methacrylate. One or more of these can be used.

[0091] In addition, examples of non-acrylic vinyl monomers include styrene monomers such as styrene, α-methylstyrene, vinyltoluene (a mixture of m-methylstyrene and p-methylstyrene), and chlorostyrene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl octanoate, vinyl decanoate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl pivalate, vinyl octanoate, vinyl monochloroacetate, divinyl adipate, vinyl crotonate, vinyl sorbate, vinyl benzoate, and vinyl cinnamate; and vinyl halide monomers such as vinyl chloride and vinylidene chloride, one or more of which may be used.

[0092] The Tg-adjusting monomer is preferably used to determine the appropriate amounts of the hydroxyl group-containing monomer and the carboxyl group-containing monomer, and to make the remainder thereof. The Tg of the copolymer is determined by the following Fox equation.

[0093]

[0094] W n : Mass percentage of each monomer (mass %)

[0095] Tg n : Tg (K) of the homopolymer of each monomer

[0096] The acrylic resin used in the present invention can be obtained by known free radical polymerization. Emulsion polymerization, suspension polymerization, solution polymerization, bulk polymerization, etc. can all be used. From the perspective of handleability, solution polymerization is preferred. Examples of water-soluble organic solvents that can be used for solution polymerization include ethylene glycol n-butyl ether, isopropyl alcohol, ethanol, N-methylpyrrolidone, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, methyl cellosolve, ethyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, and propylene glycol monobutyl ether. These can be mixed with water for use.

[0097] The polymerization initiator may be any known compound that generates free radicals, and water-soluble azo polymerization initiators such as 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide are preferred. The polymerization temperature, time, etc. can be appropriately selected.

[0098] The mass average molecular weight (Mw) of the binder resin (B) is preferably about 10,000 to 200,000. A more preferred range is 20,000 to 150,000. An Mw of 10,000 or greater is preferred because it improves the toughness and strength of the coating film. An Mw of 200,000 or less is preferred because it prevents a significant increase in the viscosity of the coating solution and improves coating properties.

[0099] The antistatic layer of the present invention preferably contains 10% by mass or more of the binder resin (B), more preferably 40% by mass or more, relative to 100% by mass of the total solid content in the antistatic layer. A content of 10% by mass or more is preferred because it increases the static water contact angle.

[0100] In the antistatic layer of the present invention, relative to the total solids 100 quality % in the antistatic layer, binder resin (B) is preferably below 70 quality %, more preferably below 60 quality %.When binder resin (B) is below 70 quality %, can not interact with antistatic agents such as polythiophene, is difficult for gathering, is preferred.In addition, can suppress and form the antistatic layer that antistatic layer forms and gather in the composition, can avoid the uniformity of antistatic layer to descend, and then can also bring the raising of antistatic property, the raising of transparency.

[0101] (Crosslinking agent (A))

[0102] In the present invention, in order to form a cross-linked structure in the antistatic layer, the antistatic layer is formed by the composition comprising a crosslinking agent (A). By containing a crosslinking agent (A), durability improves, and the situation that antistatic performance declines when processing under high temperature and high humidity conditions is also suppressed, so it is preferred. As specific crosslinking agent, urea system, epoxy system, melamine system, isocyanate system, oxazoline system, carbodiimide system, aziridine system etc. can be enumerated. In one mode, crosslinking agent (A) comprises at least one selected from acrylamide, melamine resin, carbodiimide, oxazoline, isocyanate and aziridine. Crosslinking agent (A) is particularly preferably melamine system, oxazoline system, carbodiimide system, aziridine system. In addition, in order to promote crosslinking reaction, catalyst etc. can be suitably used as needed.

[0103] The crosslinking agent (A) contained in the antistatic layer of the present invention preferably contains 15% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass relative to 100% by mass of the total solid content in the antistatic layer. When it is 15% by mass or more, the crosslinking points with the binder increase, thereby obtaining a stronger coating film with a higher crosslinking density, and having good heat resistance and alcohol resistance, which is preferred.

[0104] The crosslinking agent (A) is preferably 75% by mass or less, for example 65% by mass or less, or 55% by mass or less relative to 100% by mass of the total solid content in the antistatic layer. When it is 75% by mass or less, heat resistance and alcohol resistance can be maintained while the static contact angle is maintained within the target range.

[0105] In the antistatic layer of the present invention, a surfactant may be used to improve the appearance. Examples of the surfactant include nonionic surfactants such as polyoxyethylene octylphenyl ether, polyoxyethylene alkyl ether, and polyoxyethylene sorbitan fatty acid esters; fluorine-based surfactants such as fluoroalkyl carboxylic acids, perfluoroalkyl carboxylic acids, perfluoroalkylbenzenesulfonic acids, perfluoroalkyl quaternary ammoniums, and perfluoroalkyl polyoxyethylene ethanols; and silicone-based surfactants.

[0106] In addition to the above, the antistatic layer may contain a lubricant, a pigment, an ultraviolet absorber, a silane coupling agent, and the like as needed within a range not inhibiting the purpose of the present invention.

[0107] In one embodiment, the laminated polyester film contains substantially no organosilicon compound. Preferably, the antistatic layer contains substantially no organosilicon compound.

[0108] In the present application, "substantially free of silicone compounds" is defined by being 50 ppm or less when the Si element is quantified by fluorescent X-ray analysis, preferably 10 ppm or less, and most preferably an amount of below the detection limit. "This is because, even if a silicone component is not intentionally added to the film, there are cases where a contaminant component from foreign matter, dirt attached to the production line or device in the manufacturing process of the raw material resin or film, is peeled off and mixed into the film.

[0109] By making the laminated polyester film substantially free of silicone compounds, migration of silicone to the protected article can be avoided when the present antistatic film is used as a protective film, and the adverse effects on the final product can be reduced.

[0110] The thickness of the antistatic layer of the present application is preferably 0.005 μm or more and 1 μm or less. More preferably, it is 0.01 μm or more and 0.5 μm or less, and further preferably, it is 0.01 μm or more and 0.2 μm or less. When the thickness of the antistatic layer is 0.005 μm or more, an antistatic effect is obtained, which is preferable. On the other hand, when it is 1 μm or less, coloring is less and the transparency becomes higher, and thus it is preferable.

[0111] The surface resistivity of the antistatic layer of the present application is 9 [logΩ / D] or less. Further preferably, it is 8 [logΩ / D] or less, and further preferably, it is 7 [logΩ / D] or less. By setting the surface resistivity to 9 [logΩ / D] or less, the charging of the protective film can be suppressed, the attachment of foreign matter in the process can be prevented, and further, the adverse effects of the charging of the protective film on the electrical properties of the protected article can be suppressed.

[0112] In addition, the lower limit of the surface resistivity of the antistatic film can not be particularly limited, and it is preferably 3 [logΩ / D] or more. When the surface resistivity of the antistatic film is less than 3 [logΩ / D], the processing cost of the antistatic layer increases, and thus it is not preferable.

[0113] The water adhesion energy of the surface of the antistatic layer of the antistatic film of the present application is preferably 3.5 mJ / m 2 or less, and further preferably, it is 3.2 mJ / m 2 or less, for example, it is 2.9 mJ / m 2 or less.

[0114] When the water adhesion energy is 3.5 mJ / m 2 or less, the detachability of the protective film from the laminating roll is improved when it is used as a protective film and is laminated to the adherend with the laminating roll, and thus it is preferable. In order to make the water adhesion energy 3.5 mJ / m 2The following can be achieved by adding an appropriate amount of low surface free energy components to the antistatic layer. By using a polymer containing low surface free energy components in the above-mentioned binder resin, a protective film with reduced adhesion energy and no migration to the adherend can be provided, which is preferred.

[0115] For example, in the present invention, the polymer containing a low surface free energy component may be a conductive polymer, may be the binder resin (B), or both may contain a low surface free energy component.

[0116] The adhesion energy of water on the surface of the antistatic layer of the antistatic film of the present invention is preferably 1.1 mJ / m 2 More than 1.3 mJ / m 2 By setting the adhesion energy of water within such a range, when processing an adhesive layer or the like on the antistatic layer, the wettability is improved and defects such as repellency are less likely to occur.

[0117] The static contact angle of water on the surface of the antistatic layer of the antistatic film of the present invention is 70° to 95°, for example, 75° to 95°, or 80° to 95°.

[0118] By setting the static contact angle of water within such a range, it is possible to suppress the interaction between the surface of the protective film opposite to the adhesive layer-laminated surface and the laminating roller from becoming stronger.

[0119] In the present invention, it is important to set the static contact angle of water and the adhesion energy within the above ranges.

[0120] For example, the adhesion energy of water is 3.5 mJ / m 2 Films with a static water contact angle exceeding 95° have good releasability from laminating rolls, but coating properties deteriorate when processing the adhesive layer onto the antistatic layer, leading to a tendency for the protective film to have many defects. This tendency is particularly pronounced when the static water contact angle significantly exceeds 95°.

[0121] Here, the laminated polyester film of the present invention is characterized in that

[0122] (1) Surface resistivity: 3 [logΩ / □] or more and 9 [logΩ / □] or less;

[0123] (2) Static contact angle of water: 70° or more and 95° or less;

[0124] (3) Water adhesion energy: 3.5mJ / m 2 the following.

[0125] By having all of these (1) to (3), when the adhesive layer is laminated on the antistatic film and used as a protective film, a protective film can be provided that has good releasability from a laminating roll when laminating the protective film, and has reduced peeling charge and foreign matter adhesion during peeling.

[0126] By using an antistatic film that satisfies the above-mentioned range of static contact angle of water and adhesion energy as a protective film, a protective film can be provided in which the adhesive layer on the antistatic layer has good processability (e.g., good wettability and few defects), suppresses the charging of the protective film, has good detachability from the laminating roller, and has excellent lamination.

[0127] The haze of the laminated polyester film of the present invention is preferably 3.0% or less. It is more preferably 2.5% or less, even more preferably 2.0% or less, for example, 1.5% or less. It is further preferably 1.0% or less. A haze of 3.0% or less is preferred because it allows for appearance inspection, etc., while the protective film is bonded to an adherend. This is particularly preferred when the adherend is a member for optical applications. The haze can be 0, for example, 0.1% or greater.

[0128] The haze of the laminated polyester film of the present invention after heating at 140°C for 10 minutes is preferably 1.5 times or less of the haze before heating. It is more preferably 1.3 times or less, and even more preferably 1.2 times or less. A haze of 1.5 times or less is preferred because it allows for appearance inspection, etc., while the protective film is attached to an adherend. This is particularly preferred when the adherend is a member for optical applications.

[0129] The total light transmittance of the laminated polyester film (antistatic film) used in the present invention is preferably 80% or higher. It is more preferably 85% or higher, and even more preferably 88% or higher. A total light transmittance of 90% or higher is extremely preferred. A total light transmittance of 80% or higher is preferred because it allows for appearance inspection, etc., while the protective film is bonded to an adherend. This is particularly preferred when the adherend is a member for optical applications.

[0130] The change in surface resistivity of the antistatic layer after the alcohol rub test is preferably 1.3 times or less of the surface resistivity before the test. More preferably, it is 1.2 times or less, and even more preferably, it is 1.1 times or less. A change of 1.3 times or less is preferred because the initial surface resistivity is maintained when the protective film is formed even when alcohol is used in steps such as bonding.

[0131] The regional surface average roughness (Sa) of the surface of the antistatic layer is preferably in the range of 1 to 40 nm, more preferably 1 to 30 nm. More preferably, it is 1 to 10 nm. The maximum protrusion height (P) of the surface of the antistatic film used in the present invention is preferably 2 μm or less, more preferably 1.5 μm or less. More preferably, it is 0.8 μm or less. When Sa is 40 nm or less and P is 2 μm or less, there is no need to worry about the adhesive surface becoming rough even when the adhesive layer is stacked and wound into a roll, which is preferred.

[0132] As a method for applying a laminated antistatic layer to the surface of a substrate film, there are methods in which a coating solution prepared by dispersing / dissolving the antistatic agent, binder resin, etc. in a solvent is applied using a gravure roll coating method, a reverse roll coating method, an air knife coating method, a dip coating method, a rod coating method, a spin coating method, etc. There are no particular limitations on the coating method suitable for the conductive composition. Alternatively, the coating layer can be provided by an online coating method during the film manufacturing process or an offline coating method after the film is manufactured.

[0133] Regarding the antistatic layer, the drying temperature for forming the antistatic layer by the above method is generally 60°C to 150°C, preferably 90°C to 140°C. From the perspective of shortening the processing time and improving productivity, a temperature of 60°C or higher is preferred. Furthermore, the inclusion of a crosslinking agent is preferred because the crosslinking reaction proceeds sufficiently. On the other hand, a temperature of 150°C or lower is preferred because the planarity of the film is maintained.

[0134] The laminated polyester film of the present invention can be coated with an adhesive, solidified and laminated adhesive layer. Adhesive can be used without particular limitation, and the laminated film obtained can be used as a protective film. The face of the laminated adhesive layer can be any side of the antistatic film. When using the antistatic film with only one-sided antistatic layer, preferably on the antistatic film, there is an antistatic layer on the face opposite to the face laminated with the adhesive layer.

[0135] Furthermore, a ceramic green sheet, a resin film, or the like may be laminated on the antistatic layer in the laminated polyester film of the present invention.

[0136] Example

[0137] In order to explain the present invention in detail, the following examples are given for illustration, but the present invention is not limited to these examples. It should be noted that the evaluation method used in the present invention is as follows.

[0138] (NMR measurement)

[0139] The ratio of the copolymer component introduced into the long-chain alkyl-containing compound having at least one reactive group was confirmed using nuclear magnetic resonance spectroscopy (1H-NMR, 13C-NMR: Varian Unity 400, manufactured by Agilent). After removing the solvent from the synthesized acrylic resin using a vacuum dryer, the dried product was dissolved in deuterated chloroform for measurement. From the resulting NMR spectrum, the peaks attributable to the chemical shift δ (ppm) at the site of each group were identified. The integrated intensity of each peak was calculated, and the composition ratio (mol %) of the copolymer component introduced into the acrylic resin was determined based on the number of hydrogen atoms at the site of each group and the integrated intensity.

[0140] (Confirmation of Tg)

[0141] The Tg of each long-chain alkyl-containing compound was determined from the composition ratio of the copolymer components determined by the NMR measurement and the Fox equation.

[0142] (Surface resistivity)

[0143] The surface resistivity of the antistatic film of the present invention was measured by adjusting the humidity at 23°C and 55% for 24 hours using a surface resistivity tester (Worksurface Tester ST-3 manufactured by SIMCO JAPAN Co., Ltd.) and evaluated according to the following criteria.

[0144] ◎: Surface resistivity 3 or more and 6 or less [logΩ / □]

[0145] ○: Surface resistivity is more than 6 and less than 9 [logΩ / □]

[0146] △: Surface resistivity is more than 9 and less than 12 [logΩ / □]

[0147] ×: Surface resistivity exceeds 12 [logΩ / □]

[0148] (Static contact angle of water)

[0149] Using a contact angle meter (DM-701, fully automatic contact angle meter, Kyowa Interface Science Co., Ltd.) at 25°C and 50% RH, water (1.8 μL) was dripped onto the antistatic layer of the antistatic film. The contact angle was measured 30 seconds later. Measurements were taken at five points, and the average value was used.

[0150] (Adhesion energy of water)

[0151] Under the conditions of 25°C and 50% RH, a contact angle meter (Kyowa Interface Science Co., Ltd.: Fully Automatic Contact Angle Meter DM-701) was used to drip water (15 μL) onto the antistatic surface of the antistatic film. After 2 seconds from the dripping, the platform was continuously tilted to measure the contact angle every 1°. In addition, the tilt angle when the drop position moves 5° from 0° was determined as the sliding angle, and the adhesion energy was calculated from this. This calculation was performed using the analysis software within this contact angle meter software (FAMES). Measurements were made at 5 points and the average value was used.

[0152] (Total light transmittance, haze)

[0153] The total light transmittance and haze of the film of the present invention were measured in accordance with JIS K 7136 using a turbidimeter (NDH7000II manufactured by Nippon Denshoku Co., Ltd.) before and after a heat treatment at 140° C. for 10 minutes.

[0154] (Glass transition temperature)

[0155] According to JIS K7121, a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.) was used to raise the temperature of 10 mg of a resin sample at 20°C / min within a temperature range of 25 to 350°C. The extrapolated glass transition starting temperature obtained from the DSC curve was defined as the glass transition temperature.

[0156] (Alcohol resistance)

[0157] The surface resistivity of the film of the present invention was measured before and after wiping it back and forth 10 times with a paper towel soaked in ethanol. Changes in appearance after the treatment were evaluated using the following criteria.

[0158] ◎: Almost no change

[0159] ○: Slightly changed

[0160] △: There is a change

[0161] ×: There is a change in the degree of mottled peeling of the antistatic layer

[0162] (Production of Long-Chain Alkyl-Containing Compound b-1 Having At Least One Reactive Group)

[0163] To a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube, 231 parts by mass of methyl methacrylate (MMA), 130 parts by mass of stearyl methacrylate (SMA), 100 parts by mass of hydroxyethyl methacrylate (HEMA), 33 parts by mass of methacrylic acid (MAA), and 1153 parts by mass of isopropyl alcohol (IPA) were added. The flask was heated to 80°C while stirring. The flask was stirred for 3 hours while maintaining the temperature at 80°C. After that, 0.5 parts by mass of 2,2-azobis-2-methyl-N-2-hydroxyethylpropionamide was added. After nitrogen purge was performed while the temperature in the flask was raised to 120°C, the mixture was stirred at 120°C for 2 hours.

[0164] Next, a decompression operation of 1.5 kPa was performed at 120°C to remove unreacted raw materials and solvents to obtain an acrylic resin containing a long-chain alkyl group. The flask was returned to atmospheric pressure, cooled to room temperature, and 1592 parts by mass of an IPA aqueous solution (water content 50% by mass) was added and mixed. Thereafter, ammonia was added using a dropping funnel while stirring to neutralize the acrylic resin containing a long-chain alkyl group so that the pH of the solution reached a range of 5.5 to 7.5, thereby obtaining an acrylic resin (b-1) containing a long-chain alkyl group having a solid content concentration of 20% by mass. The composition ratio, Tg, and acid value of the long-chain alkyl compound (b-1) having at least one reactive group based on NMR measurement are recorded in Table 1.

[0165] (Example 1)

[0166] An antistatic layer coating liquid was obtained using the blending amounts shown in Table 2.

[0167] (Antistatic layer coating liquid)

[0168]

[0169] The obtained antistatic layer coating liquid was coated on one side of A4360 (COSMOSHINE (registered trademark), manufactured by Toyobo Co., Ltd.) with a thickness of 75 μm using a gravure coater in a wet film thickness of 4.5 μm, and dried and cured at 140°C for 30 seconds in a hot air drying furnace to obtain a polyester film with an antistatic layer.

[0170] (Examples 2, 14, and 15)

[0171] An antistatic layer was formed by the same procedure as in Example 1 except that the composition was changed to that shown in Table 2.

[0172] (Example 3)

[0173] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-2 (manufactured by Baxenden, blocked isocyanate, solid content concentration 40% by mass) was used as the composition shown in Table 2.

[0174] (Examples 4 and 13)

[0175] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-3_1 (manufactured by Nisshinbo Chemical Co., Ltd., carbodiimide, solid content concentration 40% by mass) was set to the composition shown in Table 2.

[0176] (Example 5)

[0177] A crosslinking agent a-3_2 (manufactured by Nippon Shokubai Co., Ltd., carbodiimide, solid content concentration 41 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0178] (Examples 6-7)

[0179] A crosslinking agent a-1_2 (manufactured by Japan Carbide Co., Ltd., melamine resin, imino type, solid content concentration 80 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0180] (Example 8)

[0181] A crosslinking agent a-1_3 (manufactured by Japan Carbide Co., Ltd., melamine resin, imino type, solid content concentration 70 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0182] (Example 9)

[0183] A crosslinking agent a-1_4 (manufactured by Japan Carbide Co., Ltd., melamine resin, imino-hydroxymethyl type, solid content concentration 70 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0184] (Example 10)

[0185] A crosslinking agent a-1_5 (manufactured by Japan Carbide Co., Ltd., melamine resin, imino-hydroxymethyl type, solid content concentration 70 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0186] (Example 11)

[0187] A crosslinking agent a-1_6 (manufactured by Japan Carbide Co., Ltd., melamine resin, all ether type, solid content concentration 70 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0188] (Example 12)

[0189] A crosslinking agent a-1_7 (manufactured by Japan Carbide Co., Ltd., melamine resin, hydroxymethyl type, solid content concentration 70 mass%) was set to the composition of Table 2, and an antistatic layer was formed by the same procedure as in Example 1 except for this.

[0190] (Example 16)

[0191] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 and the long-chain alkyl-containing compound b-2 (solid content concentration 20 mass %) having a different amount of stearyl methacrylate from b-1 were set to the composition shown in Table 2.

[0192] (Example 17)

[0193] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 and the long-chain alkyl-containing compound b-3 (solid content concentration 20 mass %) having a hydroxyl value different from that of b-1 were set to the composition shown in Table 2.

[0194] (Example 18)

[0195] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 and the long-chain alkyl-containing compound b-4 (solid content concentration 20 mass %) having a hydroxyl value different from that of b-1 were set to the composition shown in Table 2.

[0196] (Comparative Example 1)

[0197] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 and the long-chain alkyl compound b-5 having no reactive group (Resem T-738 manufactured by Chukyo Oil & Fats Co., Ltd., solid content concentration 20% by mass) were set according to the composition shown in Table 2.

[0198] (Comparative Example 2)

[0199] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 and the long-chain alkyl compound b-6 having no reactive group (peroyl 406 manufactured by Lion Specialty Chemicals, solid content 15% by mass) were set to the composition shown in Table 2.

[0200] (Comparative Example 3)

[0201] An antistatic layer was formed by the same procedure as in Example 1 except that the crosslinking agent a-1_1 was used according to the composition shown in Table 2 and no long-chain alkyl acrylic resin was included.

[0202] Various compositions, measured values, and the like are shown below in Tables 2A to 3D.

[0203] [Table 1A]

[0204]

[0205] [Table 1B]

[0206]

[0207] [Table 2A]

[0208]

[0209] [Table 2B]

[0210]

[0211] [Table 2C]

[0212]

[0213] [Table 2D]

[0214]

[0215] [Table 3A]

[0216]

[0217] [Table 3B]

[0218]

[0219] [Table 3C]

[0220]

[0221] [Table 3D]

[0222]

[0223] The embodiments and examples disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined not by the embodiments described above but by the claims, and is intended to encompass all modifications within the meaning and scope of the claims.

[0224] The laminated polyester film of the present invention obtained in the embodiment provides an antistatic film in which an antistatic layer with low adhesion energy is laminated on at least one side of the polyester film, thereby being able to provide: when an adhesive layer is laminated on the antistatic film and used as a protective film, the protective film has good detachability from the laminating roller when the protective film is laminated, and the peeling charge and foreign matter adhesion during peeling are suppressed.

[0225] On the other hand, Comparative Example 1 does not contain a long-chain alkyl compound having at least one reactive group as a binder resin (B), so the water contact angle deviates from the range of the present invention, and the coating property deteriorates when the adhesive layer is processed on the antistatic layer, resulting in a film with many defects.

[0226] Comparative Example 2 does not contain a long-chain alkyl compound having at least one reactive group as the binder resin (B). Therefore, coating properties are poor when the adhesive layer is processed on the antistatic layer, resulting in a film with many defects.

[0227] Comparative Example 3 does not contain a long-chain alkyl compound having at least one reactive group as a binder resin (B), so the water contact angle deviates from the range of the present invention, and the coating property deteriorates when the adhesive layer is processed on the antistatic layer, resulting in a film with many defects.

[0228] Industrial applicability

[0229] The present invention relates to an antistatic film and an adhesive film having an adhesive layer laminated thereon, and particularly to a protective film for optical members (eg, components of organic EL and liquid crystal displays).

Claims

1. A laminated polyester film comprising an antistatic layer on at least one side of a substrate, The antistatic layer is a layer formed by curing a composition comprising a conductive polymer, a crosslinking agent (A), and a binder resin (B). The binder resin (B) is a long-chain alkyl compound having at least one reactive group. The antistatic layer satisfies the following (1)-(3): (1) Surface resistivity: 3 [logΩ / □] or more and 9 [logΩ / □] or less; (2) Static contact angle of water: 70° or more and 95° or less; (3) Water adhesion energy: 3.5mJ / m 2 the following.

2. The laminated polyester film according to claim 1, wherein The laminated polyester film has a total light transmittance of 80% or more and a haze of 3.0% or less.

3. The laminated polyester film according to claim 1 or 2, wherein The haze of the laminated polyester film after heating at 140° C. for 10 minutes is 1.5 times or less of the haze before heating.

4. The laminated polyester film according to any one of claims 1 to 3, wherein The change in surface resistivity of the antistatic layer after a rubbing test with alcohol is 1.3 times or less of the surface resistivity before the test.

5. The laminated polyester film according to any one of claims 1 to 4, wherein The conductive polymer is contained in an amount of 5% by mass or more and 50% by mass or less based on 100% by mass of the total solid content of the antistatic layer.

6. The laminated polyester film according to any one of claims 1 to 5, wherein The crosslinking agent (A) and the binder resin (B) are contained in the following ranges relative to 100% by mass of the total solid content in the antistatic layer: (A) 15% by mass or more and 75% by mass or less; (B) 10% by mass or more and 70% by mass or less.

7. The laminated polyester film according to any one of claims 1 to 6, wherein The hydroxyl value of the binder resin (B) is 20 mgKOH / g or more and 300 mgKOH / g or less.

8. The laminated polyester film according to any one of claims 1 to 7, wherein The binder resin (B) contains a carboxyl group.

9. The laminated polyester film according to any one of claims 1 to 8, wherein The crosslinking agent (A) contains at least one selected from the group consisting of acrylamide, melamine resin, carbodiimide, oxazoline, isocyanate, and aziridine.

10. The laminated polyester film according to any one of claims 1 to 9, wherein The laminated polyester film contains substantially no organosilicon compound. 11 . A protective film comprising a laminated polyester film according to claim 1 and a pressure-sensitive adhesive layer laminated on at least one surface thereof.

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