TW202311465A - Surface-protective film and optical component - Google Patents

Abstract

A surface-protective film and an optical component are provided. The surface-protective film (10) includes: a base film (1) formed of a resin having transparency; an antistatic agent layer (2) formed on a surface of the base film (1); and an adhesive layer (3) formed on a surface of the base film (1) opposite to the antistatic agent layer (2). The antistatic agent layer (2) includes: a first layer (2a) including a conductive polymer; and a second layer (2b) disposed on the opposite side of the base film (1) with respect to the first layer (2a) and including nanocarbons.

Description

Surface protection film and optical parts

The present invention relates to a surface protection film and an optical component.

When manufacturing and transporting optical films such as polarizing plates, retardation plates, lens films for displays, anti-reflection films, hard coat films, transparent conductive films for touch panels, and optical products such as displays using them, attach surface protection films bonded to the surface of the optical film, thereby preventing stains or scratches on the surface in a later step. In order to improve work efficiency by omitting the trouble of peeling off the surface protection film and bonding it again, the visual inspection of the optical film as a product can be performed with the surface protection film bonded to the optical film.

Conventionally, in the manufacturing process of optical products, in order to prevent scratches, stains, etc. on the surface of optical products, a surface protection film in which an adhesive layer is provided on one side of a base film is generally used. The surface protection film is bonded to the optical film via a slightly adhesive adhesive layer. The purpose of making the adhesive layer slightly adhesive is to facilitate peeling when the used surface protection film is peeled off from the surface of the optical film, and to prevent the adhesive from adhering to the adherend, that is, the optical film of the product. Residue (prevents so-called residue).

As a surface protection film, the film which provided the antistatic layer on the surface opposite to an adhesive layer of a base film is used frequently. By providing an antistatic layer on the surface of the surface protection film, static electricity generated during the handling and handling of the optical product with the surface protection film attached in the manufacturing steps of the optical product is suppressed. Thereby, adsorption of dust and dust in the environment is prevented, and appearance inspection can be easily performed in a state where the surface protection film is bonded to the optical film. In addition, when the used surface protection film is peeled and removed from the polarizing plate, retardation plate, etc. incorporated in the liquid crystal display panel, it suppresses significant peeling static electricity, and also suppresses damage to circuits such as driver ICs.

As the antistatic layer on the surface of the surface protection film, a layer combining various surfactants (nonionic, cationic, anionic, amphoteric surfactants), polymers containing ionic groups, etc., vapor-deposited metal or metal oxide are proposed. , a layer combining metal or metal oxide particles, and the like. The antistatic layer combined with surfactants and polymers containing ionic groups is easily affected by the humidity in the environment. The antistatic effect is high in an environment with high humidity, but the antistatic performance is remarkable in an environment with low humidity. deteriorating subject. On the other hand, the antistatic layer added with metal and metal oxide particles is not easily affected by the humidity in the environment, but it is not easy to show transparency, so it cannot be used for the inspection of optical products, especially when the surface protection film is attached. Check in the state. As an antistatic layer that is not easily affected by the humidity in the environment and has transparency, there are antistatic layers deposited with metal oxides such as indium tin oxide (ITO) and antimony tin oxide (ATO). The problem of the very high cost of evaporation.

Patent Document 1 discloses a surface protection film in which an antistatic layer is provided on one surface of a polyester film, an antifouling layer is provided on the layer, and a slightly adhesive layer is provided on the opposite surface. The antistatic layer contains a conductive polymer obtained by polymerizing thiophene and/or a thiophene derivative. However, there is a problem that when the antistatic layer is formed using the aforementioned conductive polymer, problems such as an increase (deterioration) in surface resistivity due to oxidative degradation, photodegradation, etc. occur over time.

In order to solve such an increase (deterioration) of surface resistivity over time, Patent Document 2 proposes a surface protection film in which an antistatic layer contains polyanilinesulfonic acid, polythiophenes doped with polyanions, and a binder. This surface protection film suppresses the increase in surface resistivity (deterioration) over time by using polyaniline sulfonic acid in the antistatic layer, but it may be colored from yellow to green by polyaniline, so it is not easy to use for optical parts.

Patent Document 3 proposes an antistatic film that has good transparency (total light transmittance) and good adhesion to the antistatic layer of the substrate, and also has a conductive layer containing nanocarbon and a polymer, and the aforementioned antistatic film An antistatic film having a surface resistivity of 1×10 ¹¹ Ω/□ or less. However, there is the following problem: Since the antistatic film uses nanocarbons such as carbon nanotubes as an antistatic agent, although the surface resistance value increases little over time, when it is in a humid and hot environment (such as 60 ° C, relatively 90% humidity, etc.), the surface resistance value increases (deteriorates).

Patent Document 4 proposes a thermosetting antistatic coating agent containing polythiophene and a conductive filler. The thermosetting antistatic coating agent has little change in surface resistivity over time. However, there is a problem that the surface resistance value increases (degrades) when this thermosetting antistatic coating agent is placed in a high-temperature humid heat state (conditions such as a temperature of 60° C. and a relative humidity of 90%). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-026817 [Patent Document 2] Japanese Patent Reexamination No. 2018-012545 [Patent Document 3] Japanese Patent Laid-Open No. 2012-166452 [Patent Document 4] Japanese Patent Laid-Open No. 2016-216714

[Problems to be Solved by the Invention]

One embodiment of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface protection film and an optical component that are unlikely to cause an increase in surface resistance value. [Means to solve the problem]

One embodiment of the present invention provides a surface protection film. The surface protection film includes: a base film made of a transparent resin; an antistatic agent layer formed on one side of the base film; and an adhesive layer formed On the surface of the base film opposite to the antistatic agent layer, the antistatic agent layer has: a first layer comprising a conductive polymer; The opposite side of the material film, and contains nanocarbon.

The surface protection film may have a release film attached to the side opposite to the base film of the adhesive layer.

The aforementioned adhesive layer is preferably composed of an acrylic adhesive.

Another embodiment of the present invention provides an optical component bonded with the aforementioned surface protection film. [Efficacy of the invention]

One embodiment of the present invention can provide a surface protection film and an optical component that are unlikely to cause an increase in surface resistance.

Hereinafter, the present invention will be described in detail based on the embodiments. FIG. 1 is a cross-sectional view showing a surface protection film according to an embodiment. As shown in FIG. 1 , in a surface protection film 10 according to the embodiment, an antistatic agent layer 2 is formed on one surface (upper surface in FIG. 1 ) of a base film 1 . An adhesive layer 3 is formed on the surface (the lower surface in FIG. 1 ) of the base film 1 opposite to the antistatic agent layer 2 .

[Base film] As the base film 1, what consists of resin which has transparency and flexibility is used. Thereby, the external appearance inspection of an optical component can be performed in the state which bonded the surface protection film 10 to the optical component which is a to-be-adhered body. In terms of the base film 1 used as the base film 1, it is preferable to use polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate, polyethylene terephthalate, Films made of polyester such as butylene phthalate (polyester film). In addition to polyester films, films made of other resins can also be used as long as they have required strength and optical adaptability. The base film 1 may be an unstretched film, or a uniaxially or biaxially stretched film. In addition, the stretch ratio of the stretched film and the orientation angle in the axial direction accompanying the crystallization of the stretched film can be controlled to specific values.

"Transparent" means, for example, that the visible light transmittance calculated as the average value of the transmittance in the thickness direction in the entire wavelength range is 50% or more (preferably 70%) when the measurement is performed within the range of the measurement wavelength of 380nm to 780nm. above, more preferably above 80%). The light transmittance can be measured in accordance with "Plastic - Calculation of Total Light Transmittance and Total Light Reflectance" specified in JIS K 7375:2008.

The thickness of the base film 1 is not particularly limited. For example, a thickness of about 12 μm to 100 μm is preferable, and a thickness of about 20 μm to 50 μm is more preferable because it is easy to handle. In addition, surface modification by corona discharge, application of a primer, and other easy-adhesive treatments may be performed on the surface of the base film 1 as needed.

[Antistatic agent layer] The antistatic agent layer 2 is formed by laminating a first layer 2 a made of a conductive polymer and a second layer 2 b made of nanocarbon in this order from the base film 1 side. The 2nd layer 2b is provided in the side (upper side in FIG. 1) opposite to the base film 1 with respect to the 1st layer 2a.

A layer containing a conductive polymer may have an increase (deterioration) in surface resistivity accompanied by oxidative degradation or photodegradation over time, but, in the surface protection film 10, by forming a layer on the surface of the first layer 2a ( The surface opposite to the base film 1) is provided with the second layer 2b made of nanocarbon, thereby overcoming the problem of oxidative degradation or photodegradation of the first layer 2a made of the conductive polymer.

When the layer containing nanocarbon is in a hot and humid environment (such as 60°C, 90% relative humidity, etc.), the surface resistance value may increase (deteriorate), but, in the surface protection film 10, by the presence of The antistatic effect of the first layer 2a between the second layer 2b and the base film 1 also overcomes the problem of deterioration of the second layer 2b in a hot and humid environment.

Examples of the conductive polymer used for the first layer 2a include polyaniline, polythiophene, polypyrrole, and derivatives thereof. Examples of polyaniline and its derivatives include polyaniline (manufactured by ALDRICH), polyaniline (aniline green salt; emeraldine) (manufactured by ALDRICH), OMEGACON (registered trademark) D1033W, OMEGACON (registered trademark) NW-D102MT, OMEGACON (registered trademark) NW-F102ET, OMEGACON (registered trademark) NW-F101MEK (above, manufactured by Nissan Chemical Industry Co., Ltd.), AQUAPASS (registered trademark) 01X (manufactured by Mitsubishi Chemical Corporation), polyaniline toluene solution PANT (manufactured by Kaken Chemical Industry Co., Ltd. system), etc.

As commercial products of polythiophene and its derivatives, 3,4-ethylenedioxythiophene (3,4-ethylenedioxythiophene) (BAYTRON (registered trademark) MV2), 3,4-ethylenedioxythiophene/poly Styrenesulfonate (3,4-polyethylenedioxythiophene/polystyrenesulfonate) (BAYTRON (registered trademark) P, BAYTRON (registered trademark) C), BAYTRON (registered trademark) FE, BAYTRON (registered trademark) MV2, BAYTRON (registered trademark) P , BAYTRON (registered trademark) PAG, BAYTRON (registered trademark) PHC V4, BAYTRON (registered trademark) PHS, BAYTRON (registered trademark) PH, BAYTRON (registered trademark) PH500, BAYTRON (registered trademark) PH510 (above, manufactured by STARK) , SEPLEGYDA (registered trademark) AS-Q, SEPLEGYDA (registered trademark) AS-D, SEPLEGYDA (registered trademark) AS-H (above, manufactured by Shin-Etsu Polymer Co., Ltd.), conductive coating S-983, conductive coating S-495, Conductive coating S-948 (above, manufactured by Chukyo Oil Co., Ltd.), Denatron P-502RG, Denatron P-560ST, Denatron P-500NT, Denatron P-200HC, Denatron P-800SL (above, manufactured by NAGASE CHEMTEX), PED500 ( Chemical research industry company system), etc.

Examples of polypyrrole and derivatives thereof include polypyrrole (manufactured by ALDRICH), SSPY (manufactured by Kaken Sangyo Co., Ltd.), and the like.

As the conductive polymer, polythiophene is preferable in terms of antistatic property and coloring property (color feeling). As polythiophene, polyethyleneoxythiophene (Polyethylene oxythiophene) is preferred, and polyethylenedioxythiophene (PEDOT) is particularly preferred. Polyethylenedioxythiophene is preferably doped with polystyrenesulfonic acid (PSS) as a dopant. Polyethylenedioxythiophene doped with PSS has the property of being easily soluble in water, and has the advantages of excellent heat resistance, moisture resistance and UV stability.

One type of conductive polymer may be used alone, or a plurality of types may be used in combination. In addition, in order to improve the applicability of the antistatic agent to the substrate film 1, the adhesion of the antistatic agent layer to the substrate film, the film strength of the antistatic agent layer, and the durability of the film (abrasion resistance, solvent resistance, etc.) ), a binder resin, a crosslinking agent, a UV absorber, an antioxidant, a leveling agent (wettability improving agent), an adhesion improving agent, etc. can be added to the conductive polymer.

In order to form the first layer 2a, it is preferable to form a film of a conductive polymer to which a binder resin is added than to form a film of a conductive polymer alone. Examples of the binder resin include acrylic resins, epoxy resins, urethane resins, phenol resins, polyester resins, and the like. In order to crosslink (also called curing) these resins, a crosslinking agent may be added to the binder resin as needed. As a crosslinking agent, an isocyanate compound, a melamine compound, an epoxy compound, a metal chelate compound, etc. are mentioned.

A known method may be used for forming the first layer 2 a on the base film 1 . For example, a paint containing an antistatic agent (a paint containing an antistatic agent and a binder resin) is applied to the base film 1 by a known coating method. The first layer 2a can be formed by curing the formed coating film by heating or ultraviolet irradiation. As the coating method, reverse coating, comma knife coating, gravure coating, slit coating, Mailer bar coating, air knife coating and the like are included.

Carbon nanotubes (CNT), graphene, fullerene, etc. are mentioned as nanocarbon used for the 2nd layer 2b. Carbon nanotubes include single-layer CNTs and multilayer CNTs. Single-layer CNT, multilayer CNT, graphene, and fullerene all have excellent antistatic functions, but single-layer CNT, graphene, and fullerene are expensive, so multilayer CNT is easy to use. In order to prevent the first layer 2a from being exposed to the air, the second layer 2b is formed on the surface of the first layer 2a. Thus, the first layer 2a is not directly exposed to the air, so the first layer 2a is less likely to be oxidized and deteriorated.

Since nanocarbon alone cannot exhibit film strength, it is better to use it as a coating by adding binder resin, dispersant, etc. In addition, in order to improve the applicability of the antistatic agent, the adhesion of the antistatic agent layer (adhesion to the first layer 2a), the film strength of the antistatic agent layer, and the durability of the film (abrasion resistance, solvent resistance) Properties, etc.), you can add cross-linking agents, UV absorbers, antioxidants, leveling agents (wettability improvers), adhesion improvers, etc. to nanocarbon.

One type of nanocarbon may be used, or two types may be used in combination. Examples of the binder resin include acrylic resins, epoxy resins, urethane resins, phenol resins, polyester resins, and the like. In order to crosslink (also called curing) these resins, a crosslinking agent may be added to the binder resin as needed. As a crosslinking agent, an isocyanate compound, a melamine compound, an epoxy compound, a metal chelate compound, etc. are mentioned.

In order to form the second layer 2b, a commercially available paint can be used as the paint for the antistatic agent. As a commercial item, Denatron C-300, Denatron CD-001 (above, manufactured by Nagase Chemex Co., Ltd.), Colcoat CS-3002, Colcoat CS-3202 (above, manufactured by Colcoat Inc.) etc. are mentioned.

The method of forming the second layer 2b on the surface of the first layer 2a may be a known method. For example, a nanocarbon-containing paint (a paint containing nanocarbon and a binder resin) is applied to the surface of the first layer 2 a by using a known coating method. The second layer 2b can be formed by curing the formed coating film by heating, ultraviolet radiation, or the like. As the coating method, there are reverse coating, comma knife coating, gravure coating, slit coating, Mailer bar coating, air knife coating and the like.

The thicknesses of the first layer 2a and the second layer 2b are not particularly limited. The thickness of the first layer 2a is determined by the amounts of the conductive polymer and the binder resin. The thickness of the second layer 2b is determined by the amount of nanocarbon and binder resin. The thickness of the first layer 2a and the second layer 2b can be adjusted so that the surface intrinsic resistance value becomes 10 to the 7th power (10 ⁷ ) to 10 to the 9th power (10 ⁹ ) or so.

[Adhesive layer] The adhesive layer 3 preferably has the characteristics of adhering to the surface of the adherend, easy to peel off after use, and less likely to contaminate the adherend. Examples of the adhesive used for the adhesive layer 3 include adhesives such as acrylic adhesives, urethane adhesives, and rubber adhesives. Adhesive resins such as polyethylene vinyl acetate resin can also be used as the adhesive. Among them, acrylic adhesives and urethane adhesives are particularly preferable.

As the acrylic adhesive, a crosslinking agent is preferably added to a (meth)acrylic polymer (acrylic resin composition). The (meth)acrylic polymer is preferably: main monomers such as n-butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, etc.; acrylonitrile, vinyl acetate, methyl Comonomers of methyl acrylate, ethyl acrylate, etc.; and functional groups of acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxybutyl acrylate, glycidyl methacrylate, N-methylolmethacrylamide, etc. Polymers formed by copolymerization of monomers. The composition of monomers constituting the (meth)acrylic polymer is preferably 50% or more of (meth)acrylic monomers, and may be 100% of (meth)acrylic monomers.

The crosslinking agent crosslinks the (meth)acrylic polymer. As a crosslinking agent, an isocyanate compound, an epoxy compound, a melamine compound, a metal chelate compound, etc. are mentioned. The amount of the crosslinking agent added can be determined in consideration of the type of (meth)acrylic polymer, degree of polymerization, amount of functional groups, and the like. Although the addition amount of a crosslinking agent is not specifically limited, Preferably, it is about 0.5 mass part - 1.0 mass parts of crosslinking agents with respect to 100 mass parts of (meth)acrylic-type polymers.

As the urethane-based adhesive, a polyurethane-based resin containing a polyol component and a polyisocyanate component is preferable. The polyurethane-based resin can be selected in consideration of adhesiveness, wettability, contamination by adherends, and the like. The polyol component and the polyisocyanate component are not particularly limited. The polyurethane-based resins may be used alone or in combination of two or more kinds.

As a polyol component, polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, castor oil type polyol etc. are mentioned, for example. These polyol components may be used alone or in combination of two or more.

As the polyisocyanate component, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, multimer of diisocyanate, etc. are used. These polyisocyanate components may be used alone or in combination of two or more.

Commercially available polyurethane adhesives include: CYABINE (registered trademark) SH-101, SH-101M, SP-205, SP-220 (manufactured by TOYOCHEM Co., Ltd.), ARACOAT (registered trademark) ) FT100, FT200 (Arakawa Chemical Industry (stock) system), UN1175, UN1176 (Daido Chemical Industry (stock) system), etc. The adhesive layer can be formed by cross-linking or curing a polyurethane-based adhesive.

In order to accelerate the crosslinking reaction, a crosslinking catalyst may be added as an additive to the adhesive layer 3 as needed. In order to improve the adhesiveness between the base film 1 and the adhesive, an adhesive improving agent such as a silane coupling agent may be added as an additive to the adhesive layer 3 as needed. Additives such as antistatic agents, antioxidants, and ultraviolet absorbers can be added to the adhesive layer 3 as needed.

The thickness of the adhesive layer 3 is not particularly limited, for example, it is preferably about 5 μm to 40 μm, more preferably about 10 μm to 30 μm. In addition, the adhesive force (low-speed adhesive force) at a peeling speed of 0.3 m/min to the surface of the adherend of the surface protection film is preferably 0.3 N/25 mm or less, more preferably 0.2 N/25 mm or less. In addition, the adhesive force (high-speed adhesive force) at a peeling speed of 30 m/min is preferably at most 0.8 N/25 mm. If the high-speed adhesive force exceeds 0.8N/25mm, the workability when peeling off the protective film after use may deteriorate. For adjusting the adhesive force, known methods such as changing the composition of the adhesive, adjusting the amount of curing agent added, adjusting the amount of tackifier, and adhesive force regulator can be used. By these methods, it is only necessary to make the adhesive force of the adhesive layer 3 match a predetermined adhesive force.

As a method of forming the adhesive layer 3 on the surface of the base film 1, a well-known method can be used. Specifically, known coating methods such as reverse coating, comma knife coating, gravure coating, slot coating, Meyler bar coating, and air knife coating can be used.

FIG. 2 is a cross-sectional view showing a surface protection film 11 with a release film in which the release film 4 is bonded to the surface protection film 10 . As shown in FIG. 2 , a known release film can be used as the release film 4 . As the release film 4, a polyolefin film such as a polyethylene film or a polypropylene film, a fluorine film, or the like can be used as a film monomer. The release film 4 may be a release film in which a resin film is treated with a release agent (also referred to as a release agent). Examples of the resin film include polyester films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), and polyamide films. Examples of the release agent include silicone resins, long-chain alkyl group-containing resins, fluororesins, and the like. Among them, a release film obtained by treating a PET film with a silicon-based release agent is preferable. The thickness of the release film is not particularly limited, but from the viewpoint of workability and cost, release films with a thickness of 12 μm to 38 μm are often used.

The method of forming the adhesive layer 3 on the base film 1 and the method of bonding the release film 4 to the adhesive layer 3 can be performed by known methods, and are not particularly limited. Specifically, the following examples include: (1) After coating and drying the resin composition for forming the adhesive layer 3 on one side of the base film 1 to form the adhesive layer 3 , bonding and peeling the adhesive layer 3 The method of the film 4, (2) After coating and drying the resin composition for forming the adhesive layer 3 on the surface of the release film 4 to form the adhesive layer 3 , bonding the base film 1 to the adhesive layer 3 method, etc., but either method can be used.

Fig. 3 is a sectional view showing an embodiment of the optical component of the present invention. FIG. 3 shows an optical component 20 to which a surface protection film 10 is bonded. As shown in FIG. 3 , the surface protection film 11 with a peeling film (see FIG. 2 ) is in a state where the peeling film 4 is peeled and the adhesive layer 3 is exposed. This surface protection film (see FIG. 1 ) is bonded to an optical component 5 which is an adherend through an adhesive layer 3 .

Examples of the optical member include optical films such as a polarizing plate, a retardation plate, a lens film, a polarizing plate serving both as a retardation plate, and a polarizing plate serving both as a lens film. Such optical members are used as constituent members of liquid crystal display devices such as liquid crystal display panels, optical system devices of various scales, and the like. Moreover, as an optical member, the optical film, such as an antireflection film, a hard coat film, and the transparent conductive film for touch panels, is mentioned.

According to the optical component of the embodiment, the antistatic agent layer exists on the surface of the surface protection film in a state where the surface protection film is bonded to the optical component (optical film) which is an adherend. Thereby, static electricity generated during transport and handling of optical components can be suppressed to a low level. Therefore, it is possible to suppress the adsorption of substances that cause foreign substances such as dust and dust in the process, and to obtain an optical component with few defects. In addition, when peeling and removing the surface protection film from the optical component, the peeling static voltage can be kept low, so there is little possibility of damage to circuit components such as driver ICs, TFT elements, and gate line drive circuits. Therefore, for example, it is possible to improve the production efficiency in the steps of manufacturing liquid crystal display panels and the like, and to maintain the reliability of the production steps. The surface protection film of the embodiment can suppress the increase (deterioration) of the surface resistance value of the antistatic agent layer on the surface even when it is exposed to the outside air or a hot and humid environment, so the above-mentioned effect is not easy to change with time, so the industrial utility value big. [Example]

Next, the present invention is further illustrated by examples. (Example 1) As an antistatic agent composition containing a conductive polymer, a polythiophene-based antistatic agent (BAYTRON (registered trademark) PAG manufactured by STARK Co., Ltd.), an acrylic resin (Takamatsu oil Antistatic agent A of PESRESIN (registered trademark) SWX-079R manufactured by the company) and a methylated melamine crosslinking agent (NICARAK (registered trademark) MW-30HM manufactured by Nippon Carbide Industry Co., Ltd.).

As an antistatic agent composition containing carbon nanotubes, a carbon nanotube dispersion (DENATRON (registered trademark) CD-100 manufactured by NAGASE CHEMTEX Co., Ltd.), an acrylic resin ( Antistatic agent B of PESRESIN (registered trademark) SWX-079R manufactured by Takamatsu Oil Co., Ltd.) and methylated melamine crosslinking agent (NICARAK (registered trademark) MW-30HM manufactured by Nippon CARBIDE Industry Co., Ltd.).

A copolymer of 80 parts by mass of 2-ethylhexyl acrylate, 10 parts by mass of butyl acrylate, 7 parts by mass of methoxypolyethylene glycol (400) methacrylate and 3 parts by mass of 2-hydroxyethyl acrylate was prepared. Adhesives made of substances. The adhesive is an acrylic adhesive. With respect to 100 parts by mass of the 40% ethyl acetate solution of the adhesive, 0.3 parts by mass of lithium bis(trifluoromethanesulfonyl)imide as an antistatic agent and "TOSOH Co., Ltd. Adhesive composition 1 was obtained by stirring and mixing 2 parts by mass of CORONATE (registered trademark) HX".

The first coating was obtained by diluting the antistatic agent A 10 times with water/ethanol (the mass ratio of water/ethanol was 50/50). Apply the first paint to the surface of a polyethylene terephthalate film (PET film, base film) with a thickness of 38 μm so that the thickness after drying becomes 0.15 μm, and heat it in a hot air circulation oven at 120 ° C. Let dry for 1 minute. Thus, the first layer was formed.

The second coating was obtained by diluting the antistatic agent B 10 times with water/ethanol (the mass ratio of water/ethanol was 50/50). The second paint was applied to the surface of the first layer so that the thickness after drying would be 0.05 μm, and dried in a 120° C. hot air circulation oven for 1 minute. Thus, the second layer was formed. Through the above steps, an antistatic film in which the substrate film (PET film)/first layer (antistatic agent A)/second layer (antistatic agent B) is laminated in this order is obtained.

On the surface of the PET film on which the antistatic agent layer was not laminated, the adhesive composition 1 was applied with an applicator so that the thickness after drying was 20 μm, and dried in a hot air circulation oven at 120° C. for 3 minutes. Thus, an adhesive layer is formed.

A release film (25 μm thickness) (DIAFOIL (registered trademark) MRF-25 manufactured by Mitsubishi Chemical Corporation) treated with a silicon-based release agent was attached to the surface of the adhesive layer to obtain a surface protection film with a release film. The obtained surface protection film with release film was aged at 40°C for 3 days to obtain the surface protection film of Example 1.

(Example 2) The surface protection film of Example 2 was produced in the same manner as in Example 1 except that the thickness of the first layer and the thickness of the second layer were both 0.1 μm.

(Example 3) The surface protection film of Example 3 was produced in the same manner as in Example 1 except that the thickness of the first layer was 0.05 μm and the thickness of the second layer was 0.15 μm.

(Example 4) The surface protection film of Example 4 was produced in the same manner as in Example 2 except for the adhesive and the curing agent. As the adhesive, a urethane adhesive (ARACOAT (registered trademark) FT200 manufactured by Arakawa Chemical Industry Co., Ltd.) was used instead of the acrylic adhesive. As a curing agent, 5.7 parts by mass of "ARACOAT (registered trademark) CL2503 manufactured by Arakawa Chemical Industry Co., Ltd. (the content of non-volatile components of the curing agent is 40% by mass)" was used instead of "CORONATE (registered trademark) manufactured by TOSOH Co., Ltd. ) HX" 2 parts by mass.

(Example 5) Produced in the same manner as in Example 2, except that polyester resin (VYLONAL (registered trademark) MD-1480 manufactured by Toyobo Co., Ltd.) was used instead of acrylic resin (PESRESIN (registered trademark) SWX-079R manufactured by Takamatsu Shishishi Co., Ltd.) Surface protection film of Example 5.

(comparative example 1) The surface protection film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the thickness of the first layer was set to 0.2 μm and there was no second layer.

(comparative example 2) A surface protection film of Comparative Example 2 was obtained in the same manner as in Example 1 except that there was no first layer and the thickness of the second layer was set to 0.2 μm.

(comparative example 3) The surface protection film of Comparative Example 3 was produced in the same manner as in Example 2, except that the antistatic agent layer with a single-layer structure was used instead of the antistatic agent layer with a two-layer structure. The antistatic agent layer of the single-layer structure is formed by applying an antistatic agent in such a manner that the thickness after drying becomes 0.2 μm, and the antistatic agent is mixed with the antistatic agent A so that the mass ratio of the solid content becomes 50/50. And antistatic agent B made.

(comparative example 4) A surface protection film of Comparative Example 4 was obtained in the same manner as in Example 2 except that the positions of the first layer and the second layer were reversed.

(comparative example 5) Except not having the first layer and the second layer, the surface protection film of Comparative Example 5 was produced in the same manner as in Example 1.

The method and results of the evaluation test are shown below. (Measurement method of surface intrinsic resistance value of surface protection film) The intrinsic surface resistance value (Ω/ □).

(Evaluation method of heat and humidity resistance) After leaving the surface protection film at a temperature of 60°C and a relative humidity of 90% for a predetermined period of time (1 day or 30 days), it was left at a temperature of 23°C and a relative humidity of 50% for 1 hour. The intrinsic surface resistance value (Ω/ □).

(Evaluation method for exposure resistance) The surface protection film is left for a predetermined period of time (1 day or 30 days) under the conditions of a temperature of 23° C. and a relative humidity of 50% in a state where the surface is exposed to the air. The intrinsic surface resistance value (Ω/ □).

<Measurement method of low-speed adhesion of surface protection film> A laminating machine is used to bond the polarizing plate, which uses the TAC film as a polarizer protective film, to the surface of the glass plate. Thereafter, the surface protection film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and stored in a test environment of 23° C.×50% RH for 1 day. Thereafter, the strength when the surface protection film was peeled off in a direction of 180° at a peeling speed of 0.3 m/min was measured using a tensile tester, and this was defined as low-speed adhesive force (N/25 mm).

<Measurement method of high-speed adhesion of surface protection film> A laminating machine is used to bond the polarizing plate, which uses the TAC film as a polarizer protective film, to the surface of the glass plate. Thereafter, the surface protection film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and stored in a test environment of 23° C.×50% RH for 1 day. Thereafter, the strength when the surface protection film was peeled off at a peeling speed of 30 m/min was measured using a high-speed peel tester (manufactured by Tester Sangyo), and this was defined as high-speed adhesive force (N/25 mm).

<Measuring method of peeling static voltage of surface protective film> A laminating machine is used to bond the polarizing plate, which uses the TAC film as a polarizer protective film, to the surface of the glass plate. Thereafter, the surface protection film cut to a width of 25 mm was bonded to the surface of the polarizing plate, and stored in a test environment of 23° C.×50% RH for 1 day. After that, the surface when the surface potential of the polarizing plate surface was measured every 10 ms using a surface potentiometer (manufactured by KEYENCE Co., Ltd.) while peeling off the surface protective film at a peeling speed of 30 m/min using a high-speed peel tester (manufactured by TESTER Sangyo Co., Ltd.) The maximum value of the absolute value of the potential was taken as the peeling electrostatic voltage (kV).

<Confirmation method of surface contamination of surface protection film> A laminating machine is used to bond the polarizing plate, which uses the TAC film as a polarizer protective film, to the surface of the glass plate. After that, the surface protection film cut to a width of 25 mm was attached to the surface of the polarizing plate, and then stored in a test environment of 23° C.×50% RH for 3 days. Thereafter, the surface protective film was peeled off, and the contamination of the surface of the polarizing plate was visually observed. As the criteria for judging surface contamination, it was judged as "○" (good) when there was no contamination transfer in the polarizing plate, and "╳" (bad) when contamination transfer was confirmed in the polarizing plate.

Tables 1 to 3 show the measurement results of the surface protection films of Examples 1 to 5 and Comparative Examples 1 to 5. In Tables 1 to 3, "CNT" represents the ratio of the thickness of the second layer to the total thickness of the first layer and the second layer. "PEDOT" represents the ratio of the thickness of the first layer to the total thickness of the first layer and the second layer. "CNT/PEDOT (Mix)" indicates the mixing ratio of antistatic agent B and antistatic agent A in the antistatic agent (mixture) when the antistatic agent layer with a single-layer structure is used. "100 (50/50)" means that both the antistatic agent A and the antistatic agent B have a solid content mass ratio of 50%.

"Antistatic agent layer stacking order" indicates the stacking order of the first layer and the second layer. "○" indicates that the lamination order of the base film, the first layer, and the second layer is the order of "base film/second layer/first layer". "○" in "acrylic resin" indicates that the binder resin of the first layer and the second layer is acrylic resin. "○" in "polyester resin" indicates that the binder resin of the first layer and the second layer is polyester resin. "○" in "acrylic adhesive" indicates that an acrylic adhesive is used as the adhesive. "○" in "urethane adhesive" indicates that a urethane-based adhesive is used as the adhesive. 1.0E+09 of the surface intrinsic resistance value represents 1.0×10 to the 9th power. 1.0E+13< means that the measurement limit (1.0×10 to the 13th power) of the measurement device (high-performance high-resistivity meter) is exceeded and it becomes an overrange.

[Table 1]

[Table 2]

[table 3]

From the measurement results shown in Tables 1 to 3, the following are understood. Even when the surface protection films of Examples 1 to 5 were exposed to outside air and a humid heat environment, the surface resistance value of the antistatic agent layer did not increase (degrade). On the other hand, in Comparative Example 1 in which the antistatic agent layer was formed of only the first layer (containing a conductive polymer), it was observed that the surface resistance value of the antistatic agent layer increased (deteriorated) when exposed to external air. In Comparative Example 2 in which the antistatic agent layer was formed only of the second layer (containing nanocarbon), it was observed that the surface resistance value of the antistatic agent layer on the surface increased (deteriorated) under a hot and humid environment. In Comparative Example 3 in which the antistatic agent layer was not a two-layer structure but a single-layer structure composed of a mixture of antistatic agents A and B, the surface resistance value of the antistatic agent layer slightly increased (deteriorated) under a hot and humid environment . Under an environment exposed to external air, the surface resistance value of the antistatic agent layer on the surface greatly increases (degrades). In Comparative Example 4 in which the order of laminating the antistatic agent layers was reversed from that of Examples 1 to 5, it was observed that the surface resistance value of the antistatic agent layer on the surface increased (deteriorated) in an environment exposed to external air and a humid heat environment. . In Comparative Example 5 in which no antistatic agent layer was provided, since the surface resistivity of the surface protective film was high, it is presumed that static electricity is likely to be generated in the process. [Industrial Utilization]

The surface protection film according to the embodiment can be used to protect the surface by being bonded to optical components such as polarizing plates, retardation plates, lens films and other optical films, and other various optical components during production steps. The surface protection film of the embodiment can suppress the increase (deterioration) of the surface resistance value of the antistatic agent layer on the surface even when it is exposed to outside air or a humid heat environment. The surface protection film of the embodiment can suppress the static electricity generated when the optical product attached with the surface protection film is transported and handled in the manufacturing steps of the optical product, thereby reducing the adsorption of dust and dust in the environment. The surface protection film of the embodiment can suppress significant peeling static electricity when the used surface protection film is peeled off from the polarizing plate or retardation plate incorporated in the liquid crystal display panel, and the possibility of damage to circuits such as driver ICs is small. Therefore, the yield of the production process can be improved, and the industrial utility value is large.

1: Substrate film 2: Antistatic agent layer 2a: first layer 2b: second layer 3: Adhesive layer 4: Peel off film 5: Adhered body (optical components) 10: Surface protection film 11:Surface protection film with release film 20: Optical components

[ Fig. 1 ] is a cross-sectional view showing a surface protection film according to an embodiment. [ Fig. 2 ] is a cross-sectional view showing a surface protection film with a release film bonded to the surface protection film according to the embodiment. [ Fig. 3 ] is a sectional view showing one example of the optical component of the present invention.

1: Substrate film

2: Antistatic agent layer

2a: first layer

2b: second floor

3: Adhesive layer

10: Surface protection film

Claims (4)

A surface protection film having: The base film is made of transparent resin; An antistatic agent layer is formed on one side of the aforementioned substrate film; and an adhesive layer formed on the surface of the base film opposite to the antistatic agent layer, Wherein the aforementioned antistatic agent layer has: a first layer comprising a conductive polymer; and The second layer is provided on a side opposite to the base film with respect to the first layer, and includes nanocarbon. The surface protection film according to claim 1, wherein, A release film is bonded to the side opposite to the base film of the adhesive layer. The surface protective film according to claim 1 or 2, wherein, The aforementioned adhesive layer is composed of an acrylic adhesive. An optical component bonded with the surface protection film according to any one of Claims 1 to 3.

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