JP6190520B2 - Protective film and film for laminating transparent conductive film with protective film - Google Patents

Description

  The present invention relates to a protective film used for protecting a transparent conductive film laminating film and the like, a method for producing the same, and a transparent conductive film laminating film with a protective film.

  In various mobile electronic devices such as smartphones and tablet terminals in recent years, a touch panel is often used as a display. As a touch panel system, there are a resistive film system, a capacitive system, and the like. In the mobile electronic device, a capacitive system is mainly adopted.

  In these touch panels, a transparent conductive film in which a transparent conductive film made of patterned tin-doped indium oxide (ITO) or the like is laminated on a transparent conductive film lamination film mainly composed of a transparent plastic substrate is used. There is. As an example, a hard coat layer is provided on the side of the transparent plastic substrate on which the transparent conductive film is not laminated.

  In order to protect the surface of the transparent conductive film laminating film (or transparent conductive film) as described above where the transparent conductive film is not laminated, a protective film may be applied to the surface in order to improve handling properties. It has been proposed (Patent Documents 1 and 2). This protective film is provided with the base film and the adhesive layer, and is affixed on the film for transparent conductive film lamination through the adhesive layer.

JP 2003-154593 A JP 2003-170535 A

  Here, on the surface of the transparent conductive film laminating film with the protective film affixed (transparent conductive film laminating film with a protective film) where the protective film is not affixed, vacuum deposition, sputtering, CVD A transparent conductive film is formed by a method, an ion plating method, or the like. And the said transparent conductive film will be patterned by going through an etching process etc. after that.

  By the way, in recent years, from the viewpoint of improving the conductive performance, the transparent conductive film is a crystal of a material (for example, ITO) that forms a transparent conductive film by performing a heat treatment either before or after the patterning step. Increasing the degree of conversion is often performed.

  The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer of the protective film disclosed in Patent Documents 1 and 2 is a thermosetting acrylic pressure-sensitive adhesive. When heated as described above, the pressure-sensitive adhesive force (peeling force) is remarkably high. To rise. Therefore, even if it is going to peel a protective film after use of a protective film, it will become difficult to peel from a transparent conductive film, and workability | operativity will fall.

  The present invention has been made in view of the above situation, and a protective film having excellent peelability even after heating, a method for producing the same, and a transparent conductive film-laminated film with a protective film having excellent peelability even after heating. The purpose is to provide.

  In order to achieve the above object, first, the present invention provides a protective film comprising a base material and an adhesive layer laminated on one surface of the base material, wherein the adhesive layer is an adhesive layer. The pressure-sensitive adhesive composition comprises 60% by mass or more of one or more energy ray-curable compounds having a molecular weight of 500 to 10,000, and is free of the protective film. Provided is a protective film characterized in that the adhesive strength to alkali glass is 20 to 300 mN / 25 mm (Invention 1).

  According to the said invention (invention 1), when an adhesive layer consists of an adhesive which hardened the said adhesive composition, and an adhesive force is set to the said range, the heating when crystallizing a transparent conductive film Even if it passes through conditions, the raise of adhesive force is suppressed and the outstanding peelability is exhibited. Thus, since the protective film according to the present invention is excellent in peelability after heating, that is, heat resistance, it can also be referred to as a “heat-resistant protective film”.

  In the said invention (invention 1), at least 1 type of the said energy-beam curable compound has an alkylene oxide chain, and the quantity of the said alkylene oxide in the total amount of the said energy-beam curable compound is 35-90 mass%. (Invention 2)

  In the said invention (invention 2), it is preferable that the quantity of the energy-beam curable compound which has the said alkylene oxide chain in the total amount of the said energy-beam curable compound is 40 mass% or more (invention 3).

  In the said invention (invention 1-3), it is preferable that the said energy-beam curable compound is polyfunctional (meth) acrylate (invention 4).

  In the said invention (invention 4), it is preferable that the said polyfunctional (meth) acrylate is trifunctional or more (meth) acrylate (invention 5).

  In the said invention (invention 1-5), it is preferable that the said adhesive composition does not contain the adhesion component in which a weight average molecular weight exceeds 10,000 (invention 6).

  In the said invention (invention 1-6), the said protective film was affixed on the surface by which the transparent conductive film in the film for transparent conductive film lamination is not laminated | stacked, and the transparent conductive film was laminated | stacked on the said film for transparent conductive film lamination | stacking Thereafter, it is preferably peeled off at an arbitrary stage (Invention 7).

  In the said invention (invention 7), when the hard-coat layer is formed in the side in which the transparent conductive film in the said transparent conductive film lamination film is not laminated | stacked, the said protective film is affixed on the said hard-coat layer. Is preferable (Invention 8).

  2ndly this invention is a manufacturing method of said protective film (invention 1-8), Comprising: The coating liquid containing the said adhesive composition is apply | coated and dried on one side of the said base material, Provided is a method for producing a protective film, comprising forming a coating layer of the pressure-sensitive adhesive composition, irradiating the coating layer with energy rays, and curing the coating layer to form a pressure-sensitive adhesive layer. (Invention 9).

  In the said invention (invention 9), it is preferable to irradiate the said application layer with the energy ray in presence of oxygen (invention 10).

  3rd this invention was equipped with the film for transparent conductive film lamination | stacking, and the said protective film (invention 1-8) stuck on the surface by which the transparent conductive film in the said film for transparent conductive film lamination | stacking is not laminated | stacked. A film for laminating a transparent conductive film with a protective film is provided (Invention 11).

  The protective film according to the present invention is excellent in peelability even after heating. According to the manufacturing method of the protective film which concerns on this invention, such a protective film can be manufactured easily. Moreover, the film for transparent conductive film lamination with a protective film which concerns on this invention is excellent in the peelability of a protective film even after a heating, and exhibits favorable workability | operativity.

It is sectional drawing of the protective film which concerns on one Embodiment of this invention. It is a film sectional view for laminating a transparent conductive film with a protective film concerning one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.
〔Protective film〕
The protective film 1 which concerns on one Embodiment of this invention is comprised from the base material 11 and the adhesive layer 12 laminated | stacked on one surface (FIG. 1 upper side) of the base material 11. As shown in FIG.

(1) Base Material As the base material 11, a material having heat resistance that can withstand the heating conditions when crystallizing the transparent conductive film is used. As this heating condition, it is about 100-180 degreeC normally, Preferably it is about 130-150 degreeC. Specifically, it is preferable to use a film whose thermal shrinkage rate after heating the protective film 1 at 150 ° C. for 1 hour is within the range described later.

  As the base material 11, for example, a plastic film made of a resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyimide, polyetherimide, polycarbonate, polymethylpentene, polyphenylene sulfide, liquid crystal polymer, etc. is preferable. The film which laminated | stacked, the film which laminated | stacked the same kind or different kind of multiple layers may be sufficient. Among the above, a polyethylene terephthalate film is particularly preferable.

  In addition to the filler, the plastic film may contain additives such as a heat resistance improver and an ultraviolet absorber.

  In the base material 11, for the purpose of improving the adhesion with the pressure-sensitive adhesive layer 12, a surface treatment by an oxidation method or a concavo-convex method or a primer treatment can be applied as desired. Examples of the oxidation method include corona discharge treatment, plasma discharge treatment, chromium oxidation treatment (wet), flame treatment, hot air treatment, ozone, ultraviolet irradiation treatment, and the like. Examples include a thermal spraying method. These surface treatment methods are appropriately selected according to the type of the base film.

  In consideration of heat resistance, workability, and cost, the thickness of the substrate 11 is preferably 50 to 200 μm, particularly preferably 75 to 150 μm, and more preferably 100 to 125 μm.

(2) Pressure-sensitive adhesive layer The pressure-sensitive adhesive layer 12 is a pressure-sensitive adhesive composition (hereinafter referred to as “pressure-sensitive adhesive composition P”) containing 60% by mass or more of one or more energy ray-curable compounds having a molecular weight of 500 to 10,000. It is made of an adhesive that is cured. The pressure-sensitive adhesive layer 12 made of the pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P exhibits an excellent peelability because the increase in the pressure-sensitive adhesive force is suppressed even under the heating conditions for crystallizing the transparent conductive film. . Moreover, since the protective film 1 provided with this pressure-sensitive adhesive layer 12 becomes seasoning-less (no curing period is required), the cost merit is great.

  The molecular weight of the energy beam curable compound is 500 to 10000, preferably 1000 to 7500, and particularly preferably 1500 to 5000. When the molecular weight of the energy ray curable compound is 500 or more, the stable pressure-sensitive adhesive layer 12 can be formed. Moreover, the raise of the adhesive force after the heating of the adhesive which is obtained is suppressed because the molecular weight of an energy-beam curable compound is 10,000 or less.

  Content of the said energy-beam curable compound in the adhesive composition P is 60 mass% or more, Preferably it is 75 mass% or more, Most preferably, it is 90 mass% or more. When content of the said energy-beam curable compound is 60 mass% or more, the raise of the adhesive force after the heating of the adhesive obtained is suppressed.

  In view of the peelability after heating of the pressure-sensitive adhesive, it is preferable that the pressure-sensitive adhesive composition P does not contain a pressure-sensitive adhesive component having a weight average molecular weight exceeding 10,000, for example, an acrylic polymer generally used as a pressure-sensitive adhesive main agent. If contained, the content thereof is preferably 40% by mass or less in the adhesive composition P, particularly preferably 25% by mass or less, and more preferably 10% by mass or less. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  At least one of the energy ray-curable compounds preferably has an alkylene oxide chain, more preferably has an alkylene oxide chain of any one of 2 to 4 carbon atoms, and has an ethylene oxide chain. Is particularly preferred. This alkylene oxide chain imparts adhesive force to the resulting adhesive.

  The amount of alkylene oxide in the total amount of the energy ray-curable compound is preferably 35 to 95% by mass, particularly preferably 45 to 90% by mass, and further preferably 55 to 85% by mass. preferable. When the amount of alkylene oxide in the total amount of the energy ray-curable compound is 35% by mass or more, the obtained pressure-sensitive adhesive exhibits good adhesive force, and the amount of alkylene oxide is 95% by mass or less. The pressure-sensitive adhesive can be easily cured, and sufficient adhesion with the substrate 11 can be ensured.

  The amount of the energy ray curable compound having an alkylene oxide chain in the total amount of the energy ray curable compound is preferably 40% by mass or more, particularly preferably 60% by mass or more, and more preferably 90%. It is preferable that it is mass% or more. When the amount of the energy ray-curable compound having an alkylene oxide chain is 40% by mass or more, the obtained pressure-sensitive adhesive exhibits good adhesive force.

  As said energy-beam curable compound, what uses the adhesive force of the protective film 1 becomes the range mentioned later, and an acryl-type monomer or oligomer is preferable. Specific examples include polyfunctional (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and among them, polyfunctional (meth) acrylates are preferable. Therefore, the energy ray curable compound having an alkylene oxide chain is preferably an alkylene oxide-modified polyfunctional (meth) acrylate. In the present specification, (meth) acrylate means both acrylate and methacrylate. The same applies to other similar terms.

  From the viewpoint of curability, the polyfunctional (meth) acrylate is preferably trifunctional or more, particularly preferably tetrafunctional to hexafunctional, and more preferably tetrafunctional to pentafunctional.

  Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and hexanediol di (meth). Acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa ( And (meth) acrylate, glycerol tri (meth) acrylate, triallyl (meth) acrylate, and the like. Among the above, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate are preferable, and pentaerythritol tetraacrylate and dipentaerythritol hexaacrylate are particularly preferable. Therefore, as the polyfunctional (meth) acrylate having an alkylene oxide chain, alkylene oxide-modified pentaerythritol tetraacrylate and alkylene oxide-modified dipentaerythritol hexaacrylate are particularly preferable. According to these, the peelability after heating of the obtained pressure-sensitive adhesive is particularly excellent.

  Said polyfunctional (meth) acrylate can be used individually by 1 type or in combination of 2 or more types. More preferably, as the polyfunctional (meth) acrylate, only alkylene (especially ethylene) oxide-modified pentaerythritol tetraacrylate and / or alkylene (especially ethylene) oxide-modified dipentaerythritol hexaacrylate is used, or alkylene (especially ethylene). A combination of oxide-modified pentaerythritol tetraacrylate and / or alkylene (especially ethylene) oxide-modified dipentaerythritol hexaacrylate and pentaerythritol tetraacrylate and / or dipentaerythritol hexaacrylate not modified with alkylene oxide is used.

  When ultraviolet rays are used as the active energy ray for curing the adhesive composition P, the adhesive composition P preferably contains a photopolymerization initiator. By containing the photopolymerization initiator, the energy ray-curable compound can be efficiently cured, and the curing time and the irradiation amount of active energy rays can be reduced.

  Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4′-diethylamino Benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4 , 6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

  It is preferable that a photoinitiator is used in the quantity of 0.1-20 mass parts with respect to 100 mass parts of total amounts of an energy-beam curable compound, especially 1-10 mass parts.

  The adhesive composition P may contain various additives, for example, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softener, a filler and the like as desired.

  The thickness of the pressure-sensitive adhesive layer 12 is preferably 5 to 100 μm, particularly preferably 10 to 75 μm, and further preferably 15 to 50 μm. When the thickness of the pressure-sensitive adhesive layer 12 is within the above range, it is possible to exhibit good adhesive force and peeling force.

(3) Use As for the protective film 1 which concerns on this embodiment, it is preferable that the surface by which the transparent conductive film in the film for transparent conductive film lamination is not laminated | stacked is used as a to-be-adhered body. Thereby, while being able to protect the film for transparent conductive film lamination (or the transparent conductive film by which the transparent conductive film was laminated | stacked on the said film for transparent conductive film lamination), handling property can be improved.

  That is, the protective film 1 is attached to the surface of the transparent conductive film laminating film on which the transparent conductive film is not laminated, and after the transparent conductive film is laminated on the transparent conductive film laminating film, the protective film 1 is peeled off at any stage. It is preferable. In addition, a hard coat layer etc. may be formed in the side in which the transparent conductive film is not laminated | stacked in the film for transparent conductive film lamination | stacking, In this case, the protective film 1 will be affixed on the said hard coat layer etc. (See FIG. 2).

  However, the use of the protective film 1 is not limited to this, and various objects placed under heating conditions can be used as the adherend.

(4) Physical properties (4-1) Adhesive strength The protective film 1 according to this embodiment has an adhesive strength to an alkali-free glass of 20 to 300 mN / 25 mm, preferably 30 to 250 mN / 25 mm, particularly preferably. 40-150 mN / 25 mm. When the adhesive strength is within the above range, it can be prevented from being lifted or peeled off during the process when applied to the transparent conductive film laminating film, and the peel strength after heating is within the range described below. Easy to fit in.

  The adhesive strength in this specification is basically the adhesive strength measured by the 180 ° peeling method according to JIS Z0237: 2009. The measurement sample has a width of 25 mm and a length of 100 mm. Attached by applying pressure at 0.5 MPa and 50 ° C. for 20 minutes to the adherend, and then leaving it for 24 hours under conditions of normal pressure, 23 ° C. and 50% RH, and then measuring at a peeling rate of 300 mm / min. And

(4-2) Peeling force before heating The protective film 1 according to the present embodiment is for laminating a transparent conductive film after the protective film 1 is applied to the surface of the transparent conductive film laminating film on which the transparent conductive film is not laminated. The peeling force (peeling force before heating) when peeling the protective film 1 from the film is preferably 150 mN / 25 mm or less, particularly preferably 20 to 125 mN / 25 mm, and more preferably 40 to 100 mN / 25 mm. Preferably there is. In addition, when the hard-coat layer etc. are formed in the side in which the transparent conductive film is not laminated | stacked in the film for transparent conductive film lamination | stacking, the said protective film 1 is affixed on the said hard-coat layer etc. (hereinafter the same).

  It can prevent effectively that the peeling force after a heating becomes it too large that the said peeling force (peeling force before a heating) is 150 mN / 25mm or less. Moreover, it can prevent that the protective film 1 peels from the film for transparent conductive film lamination in the middle of various processes as the said peeling force is 20 mN / 25mm or more.

(4-3) Peeling force after heating The protective film 1 according to this embodiment is affixed to the surface of the transparent conductive film laminating film where the transparent conductive film is not laminated, and heated at 150 ° C. for 1 hour. After that, the peeling force (peeling force after heating) when peeling the protective film 1 from the transparent conductive film laminating film is preferably 150 mN / 25 mm or less, particularly preferably 50 to 125 mN / 25 mm. Further, it is preferably 75 to 100 mN / 25 mm.

  When the peeling force (peeling force after heating) is 150 mN / 25 mm or less, the protective film 1 can be peeled from the transparent conductive film lamination film without any problem. According to the protective film 1 which concerns on this embodiment, since the raise of the adhesive force after a heating is suppressed, the outstanding peelability is exhibited as mentioned above.

  The peeling force in this specification is basically an adhesive force measured by a 180 ° peeling method according to JIS Z0237: 2009. The measurement sample has a width of 25 mm and a length of 100 mm. Affixed to the body with pressure of 0.5 MPa at 50 ° C. for 20 minutes, then heated at 150 ° C. under normal pressure for 1 hour, and then left for 24 hours under conditions of normal pressure, 23 ° C. and 50% RH. Therefore, the measurement is performed at a peeling speed of 300 mm / min.

(4-4) Heat Shrinkage Rate after Heating The protective film 1 according to this embodiment has a heat shrinkage rate after heating at 150 ° C. for 1 hour, in the MD (Machine Direction) direction of the base material 11 (the line direction of production). ) Is preferably 0.0 to 1.0%, particularly preferably 0.0 to 0.7%, and more preferably 0.0 to 0.5%. Moreover, it is preferable that it is -0.2 to 0.5% in the TD (Transverse Direction) direction (direction orthogonal to the line direction of manufacture; width direction) of the base material 11, especially -0.1 to 0.4. %, Preferably 0.0 to 0.3%. Moreover, it is preferable that the absolute value of the difference of the thermal contraction rate with the film for transparent conductive film lamination | stacking mentioned later of the protective film 1 is less than 0.1 point in MD direction and TD direction.

  When the thermal shrinkage rate after heating of the protective film 1 is within the above range, and further, the absolute value of the difference in thermal shrinkage rate between the protective film 1 and the transparent conductive film laminated film is within the above range. The curling of the transparent conductive film laminating film (the transparent conductive film laminating film with the protective film) to which the protective film 1 is attached can be suppressed, and the handling property can be maintained well.

(5) Method for Producing Protective Film To produce the protective film 1 according to this embodiment, as an example, first, the adhesive composition P is formed on one surface of the substrate 11 (the upper surface in FIG. 1). If desired, a coating solution containing a diluent solvent is applied and dried to form a coating layer of the pressure-sensitive adhesive composition P.

  Examples of the diluent solvent include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, butanol, 1 -Alcohols such as methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolv solvents such as ethyl cellosolve, and the like are used.

  The concentration / viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected according to the situation. For example, the adhesive composition P is diluted so that the solid content concentration is 10 to 80% by mass. In addition, when obtaining a coating solution, addition of a dilution solvent etc. is not a necessary condition, and if a viscosity etc. which can be coated with the adhesive composition P are not necessary, a dilution solvent does not need to be added.

  The coating solution may be dried by air drying, but is usually performed by heat treatment (preferably hot air drying). When performing heat processing, it is preferable that heating temperature is 50-120 degreeC, and it is especially preferable that it is 50-100 degreeC. The heating time is preferably 10 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes.

  Next, active energy rays are irradiated to the coating layer of the pressure-sensitive adhesive composition P, the coating layer is cured to form a pressure-sensitive adhesive layer, and the protective film 1 is obtained.

As active energy rays, ultraviolet rays, electron beams and the like are usually used. The dose of the active energy ray varies depending on the type of the energy ray, for example, in the case of ultraviolet rays, preferably 50~1000mJ / cm ² in quantity, in particular 100 to 500 mJ / cm ² is preferred. In the case of an electron beam, about 10 to 1000 krad is preferable.

  The irradiation of the active energy ray can be performed in the presence of oxygen. That is, it is not necessary to perform a nitrogen purge or to laminate a cover material on the coating layer of the pressure-sensitive adhesive composition P, and the active energy rays can be irradiated in a normal atmosphere. Thereby, the adhesive composition P is fully cured. That is, the protective film 1 which concerns on this embodiment can be manufactured by the above simple methods.

[Transparent conductive film lamination film]
A film 3 for laminating a transparent conductive film with a protective film according to an embodiment of the present invention includes a film 2 for laminating a transparent electroconductive film and a surface on the side where the transparent electroconductive film 4 in the film for laminating transparent conductive film 2 is not laminated (FIG. 2). Then, the lower surface is provided with a protective film 1 attached via an adhesive layer 12.

  As an example, the transparent conductive film laminating film 2 in this embodiment is formed on the transparent plastic substrate 21 and the surface on the side where the transparent conductive film 4 of the transparent plastic substrate 21 is not laminated (the lower surface in FIG. 2). The hard coat layer 22 and the index matching layer 23 formed on the surface of the transparent plastic substrate 21 on which the transparent conductive film 4 is laminated (the upper surface in FIG. 2). However, the hard coat layer 22 and / or the index matching layer 23 may be omitted or may be replaced with a layer having another function.

  As the transparent plastic substrate 21, a conventional plastic film having transparency and heat resistance can be appropriately selected from known plastic films. Examples of such plastic film include polyester films such as polyethylene terephthalate film, polybutylene terephthalate film, polyethylene naphthalate film, polyethylene film, polypropylene film, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate film, poly Vinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, polyether imide Film, polyimide film, fluororesin Irumu, polyamide film, an acrylic resin film, norbornene resin film, a plastic film such as a cycloolefin resin film or the laminate film, and the like.

  Among these, a polyester film, a polycarbonate film, a polyimide film, a norbornene-based resin film, a cycloolefin resin film, and the like are preferable because they have strength suitable for a touch panel and the like. Among these, from the viewpoints of transparency and thickness accuracy, a polyester film is particularly preferable, and among them, a polyethylene terephthalate film is more preferable.

  Although there is no restriction | limiting in particular in the thickness of the transparent plastic base material 21, Usually, 15-300 micrometers, Preferably it is the range of 30-250 micrometers. Moreover, this transparent plastic base material 21 can perform the same surface treatment as the base material 11 of the protective film 1 mentioned above for the purpose of improving the adhesiveness with the layer provided in the surface.

  The hard coat layer 22 is not particularly limited, and is formed from a conventionally known material, for example, a material containing an energy ray curable compound. Examples of the energy ray curable compound include acrylic monomers or oligomers, and specific examples include polyfunctional (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, and the like.

  The thickness of the hard coat layer 22 is not particularly limited, but is usually 1 to 20 μm, preferably 2 to 10 μm.

  The index matching layer 23 is a layer for making it difficult to see the pattern of the transparent conductive film 4 formed on the transparent conductive film laminating film 2 and improving the visibility of the touch panel. The index matching layer 23 is configured by combining, for example, a high refractive index layer and a low refractive index layer, and the material is not particularly limited.

  The thickness of the index matching layer 23 is not particularly limited, but is usually in the range of 0.03 to 1 μm, preferably 0.05 to 0.5 μm.

  In the transparent conductive film laminating film 3 with a protective film in the present embodiment, the patterned transparent conductive film 4 is laminated on the exposed surface of the index matching layer 23 in the transparent conductive film laminating film 2 to obtain a transparent conductive film. . As an example, the transparent conductive film 4 is formed by forming a film by a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, or the like and then patterning the film by photolithography, etching, or the like. Note that heat treatment is performed before or after the patterning to increase the crystallinity of the transparent conductive film.

The material of the transparent conductive film 4 can be used without particular limitation as long as it has both transparency and conductivity. For example, tin-doped indium oxide (ITO), iridium oxide (IrO ₂ ), indium oxide (In ₂ O _3). ), Tin oxide (SnO ₂ ), fluorine-doped tin oxide (FTO), indium oxide-zinc oxide (IZO), zinc oxide (ZnO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AZO), molybdenum oxide Examples thereof include transparent conductive metal oxides such as (MoO ₃ ) and titanium oxide (TiO ₂ ).

  In the crystallization process of the transparent conductive film 4, the transparent conductive film-laminated film 3 with a protective film is usually heated to about 100 to 180 ° C, preferably about 130 to 150 ° C. Since the protective film 1 exhibits excellent peelability even after heating, the protective film 1 can be easily peeled off from the transparent conductive film laminating film 2 (transparent conductive film) after the transparent conductive film 4 is laminated. .

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, another layer may be interposed between the base material 11 and the pressure-sensitive adhesive layer 12 in the protective film 1, or on the surface of the base material 11 opposite to the pressure-sensitive adhesive layer 12 side, Other layers (for example, a hard coat layer) may be laminated.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Preparation Example 1]
100 parts by mass of ethylene oxide-modified pentaerythritol tetraacrylate (trade name “NK ester ATM-35E”, molecular weight: 1892, ethylene oxide content: 81% by mass, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable compound Solid content conversion; the same applies hereinafter) and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “Irgacure 907” manufactured by BASF AG) as a photoinitiator 3 parts by mass and 67 parts by mass of toluene as a diluting solvent were uniformly mixed to prepare a coating solution 1 of an adhesive composition having a solid content concentration of about 60% by mass. In this pressure-sensitive adhesive composition, the amount of ethylene oxide in the total amount of the energy ray-curable compound was 81% by mass.

[Preparation Example 2]
60 parts by mass of ethylene oxide-modified pentaerythritol tetraacrylate (trade name “NK ester ATM-35E”, molecular weight: 1892, ethylene oxide content: 81% by mass, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable compound , 40 parts by mass of dipentaerythritol hexaacrylate (trade name “NK Ester A-DPH”, molecular weight: 578, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable compound, and 2-methyl-1 as a photoinitiator -3 parts by mass of [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “Irgacure 907” manufactured by BASF AG) and 67 parts by mass of toluene as a diluting solvent are uniformly mixed. Then, a coating solution 2 of an adhesive composition having a solid content concentration of about 60% by mass was prepared. In this pressure-sensitive adhesive composition, the amount of ethylene oxide in the total amount of the energy ray-curable compound was 49% by mass.

[Preparation Example 3]
Ethylene oxide-modified dipentaerythritol hexaacrylate as an energy ray curable compound (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name “NK Ester A-DPH-12E”, molecular weight: 1106, ethylene oxide content: 48 mass%) 100 mass And 3 parts by weight of 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “Irgacure 907”, manufactured by BASF) as a photoinitiator, 67 parts by mass of toluene as a solvent was uniformly mixed to prepare an adhesive composition coating solution 3 having a solid concentration of about 60% by mass. In this pressure-sensitive adhesive composition, the amount of ethylene oxide in the total amount of the energy ray-curable compound was 48% by mass.

[Preparation Example 4]
80 mass of ethylene oxide-modified dipentaerythritol hexaacrylate (trade name “NK Ester A-DPH-12E”, molecular weight: 1106, ethylene oxide content: 48 mass%) manufactured by Shin-Nakamura Chemical Co., Ltd. as an energy ray curable compound Part, 20 parts by mass of dipentaerythritol hexaacrylate (trade name “NK Ester A-DPH”, molecular weight: 578, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable compound, and 2-methyl as a photoinitiator Uniformly 3 parts by mass of -1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “Irgacure 907” manufactured by BASF) and 67 parts by mass of toluene as a diluent solvent And a coating composition 4 of an adhesive composition having a solid content concentration of about 60% by mass was prepared. In this pressure-sensitive adhesive composition, the amount of ethylene oxide in the total amount of the energy ray-curable compound was 38% by mass.

[Preparation Example 5]
30 parts by mass of ethylene oxide-modified pentaerythritol tetraacrylate (trade name “NK ester ATM-35E”, molecular weight: 1892, ethylene oxide content: 81% by mass, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray-curable compound , 70 parts by mass of dipentaerythritol hexaacrylate (trade name “NK Ester A-DPH”, molecular weight: 578, manufactured by Shin-Nakamura Chemical Co., Ltd.) as an energy ray curable compound, and 2-methyl-1 as a photoinitiator -3 parts by mass of [4- (methylthio) phenyl] -2-morpholino-propan-1-one (trade name “Irgacure 907” manufactured by BASF AG) and 67 parts by mass of toluene as a diluting solvent are uniformly mixed. Then, a coating solution 5 of an adhesive composition having a solid content concentration of about 60% by mass was prepared. In this pressure-sensitive adhesive composition, the amount of ethylene oxide in the total amount of the energy ray-curable compound was 24% by mass.

[Preparation Example 6]
An acrylic ester copolymer was prepared by copolymerizing 20 parts by mass of 2-ethylhexyl acrylate, 75 parts by mass of butyl acrylate and 5 parts by mass of 4-hydroxyethyl acrylate. When the molecular weight of this acrylate copolymer was measured by the method described later, it was 200,000 in weight average molecular weight (Mw).

  Uniformly mixing 100 parts by mass of the above acrylate copolymer, 6 parts by mass of hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Co., Ltd., trade name “Coronate HX”) as a crosslinking agent, and methyl ethyl ketone as a diluting solvent Then, a coating solution 6 of an adhesive composition having a solid content concentration of about 28% by mass was prepared.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-reduced weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

[Example 1]
Application prepared in Preparation Example 1 on an easy-adhesion layer of a polyethylene terephthalate film (thickness: 125 μm, heat shrinkage: 0.5% in MD direction / 0.3% in TD direction) having an easy-adhesion layer as a substrate Liquid 1 was applied with a Mayer bar so that the film thickness after drying was 15 μm. The coating layer was dried in an oven at 70 ° C. for 1 minute, and then the pressure-sensitive adhesive layer was formed by irradiating the coating layer with ultraviolet light having a light amount of 200 mJ / cm ^{2 with} a high-pressure mercury lamp to obtain a protective film.

  The obtained protective film is a film for laminating a transparent conductive film having an index matching layer on one side and a hard coat layer on the other side (product name “OPTERIA HM540-50”, manufactured by Lintec Corporation, thickness: 50 μm, heat The film was applied to the hard coat layer side with a shrinkage ratio of 0.5% in the MD direction / 0.3% in the TD direction to obtain a transparent conductive film laminated film with a protective film. In addition, the thermal contraction rate of a base material and the film for transparent conductive film lamination | stacking is the value measured by the method similar to the test example 3 mentioned later (hereinafter the same).

[Example 2]
A transparent conductive film-laminated film with a protective film was produced in the same manner as in Example 1 except that the coating liquid 2 prepared in Preparation Example 2 was used as the coating liquid for the adhesive composition.

Example 3
A transparent conductive film-laminated film with a protective film was produced in the same manner as in Example 1 except that the coating liquid 3 prepared in Preparation Example 3 was used as the coating liquid for the adhesive composition.

Example 4
A transparent conductive film laminated film with a protective film was produced in the same manner as in Example 1 except that the coating liquid 4 prepared in Preparation Example 4 was used as the coating liquid for the adhesive composition.

Example 5
A protective film in the same manner as in Example 1 except that a polyethylene terephthalate film (thickness: 125 μm, thermal shrinkage: MD direction 0.4% / TD direction 0.2%) having an easy-adhesion layer was used as the base material. A transparent conductive film laminating film was prepared.

[Comparative Example 1]
A transparent conductive film-laminated film with a protective film was produced in the same manner as in Example 1 except that the coating liquid 5 prepared in Preparation Example 5 was used as the coating liquid for the adhesive composition.

[Comparative Example 2]
Application prepared in Preparation Example 6 on an easy-adhesion layer of a polyethylene terephthalate film (thickness: 125 μm, heat shrinkage: 0.5% in MD direction / 0.3% in TD direction) having an easy-adhesion layer as a substrate The liquid 6 was applied with an applicator so that the film thickness after drying was 20 μm, and the coating layer was dried in an oven at 90 ° C. for 1 minute. A release film (manufactured by Lintec Corporation, trade name “SP-PET381031”) having one surface peeled with a silicone-based release agent was laminated on the coating layer so that the peeling treatment surface was in contact with the coating layer. Thereafter, seasoning was carried out for 7 days in an environment of 23 ° C. and 50% RH to form an adhesive layer, and a protective film was obtained.

  Using the protective film, a transparent conductive film-laminated film with a protective film was produced in the same manner as in Example 1.

[Test Example 1] (Measurement of adhesive strength)
The protective film produced in Examples and Comparative Examples was cut into a length of 100 mm and a width of 25 mm as a test piece, applied to a non-alkali glass by pressing at 0.5 MPa at 50 ° C. for 20 minutes, and then in a standard environment. (23 ° C., 50% RH) for 24 hours. Then, in a standard environment (23 ° C., 50% RH), the protective film side is peeled off at a peeling angle of 180 ° and a peeling speed of 300 mm / min using a tensile tester, and the adhesive strength (mN / 25 mm) is obtained. It was measured.

[Test Example 2] (Measurement of peel force)
A film for laminating a transparent conductive film with a protective film prepared in Examples and Comparative Examples was cut into a length of 100 mm and a width of 25 mm as a test piece, and a tensile tester in a standard environment (23 ° C., 50% RH) Was used to peel the protective film side at a peeling angle of 180 ° and a peeling speed of 300 mm / min, and the force (peeling force; mN / 25 mm) required for peeling was measured (peeling force before heating).

  The test piece was heated in an oven at 150 ° C. for 1 hour and then left in a standard environment (23 ° C., 50% RH) for 24 hours, and the peel strength was measured in the same manner as described above (peel strength after heating). . The results are shown in Table 1.

[Test Example 3] (Measurement of heat shrinkage rate)
A test piece of 100 mm × 100 mm was cut out from the protective films prepared in Examples and Comparative Examples, and marked lines were drawn 10 mm inside from the ends in the MD direction and TD direction on one side, and the initial marked line interval was measured. Next, the test piece was heated in an oven at 150 ° C. for 1 hour, and then left in a standard environment (23 ° C., 50% RH) for 24 hours. The dimension after the test was measured at the same position as before the test, and the thermal shrinkage rate (%) in the MD direction and the TD direction was obtained by the following formula. The results are shown in Table 1.
Thermal contraction rate (%) = {(l ₀ −l ₁ ) / l ₀ } × 100
l ₁ : Dimensions after test (mm)
l ₀ : Initial marked line interval (mm)

[Test Example 4] (Measurement of curl amount)
A test piece of 100 mm × 100 mm was cut out from the protective films prepared in Examples and Comparative Examples, heated in an oven at 150 ° C. for 1 hour, and then left in a standard environment (23 ° C., 50% RH) for 24 hours. Next, the test piece was placed on a horizontal table, the maximum value of the vertical distance (mm) from the table surface was measured, and this was taken as the curl amount (mm). The results are shown in Table 1.

  As is clear from Table 1, the protective films produced in Examples 1 to 5 were suppressed from increasing in peel strength after heating. Moreover, the curl after a heating was also suppressed for the protective film produced in Examples 1-4.

  The protective film according to the present invention is useful for protecting a transparent conductive film laminating film or a transparent conductive film and improving handling properties.

DESCRIPTION OF SYMBOLS 1 ... Protective film 11 ... Base material 12 ... Adhesive layer 2 ... Transparent conductive film lamination film 21 ... Transparent plastic base material 22 ... Hard-coat layer 23 ... Optical adjustment layer 3 ... Transparent conductive film laminated film 4 with a protective film ... Transparent conductive film

Claims (8)

A protective film comprising a base material and an adhesive layer laminated on one surface of the base material,
The pressure-sensitive adhesive layer is made of a pressure-sensitive adhesive obtained by curing a pressure-sensitive adhesive composition,
The pressure-sensitive adhesive composition contains 60% by mass or more of one or more energy ray-curable compounds having a molecular weight of 500 to 10,000.
The energy ray curable compound is a tri- or higher functional (meth) acrylate,
At least one of the energy ray curable compounds has an alkylene oxide chain,
The amount of the alkylene oxide in the total amount of the energy ray-curable compound is 35 to 95% by mass,
The protective film is characterized in that the adhesive strength of the protective film to alkali-free glass is 20 to 150 mN / 25 mm. 2. The protective film according to claim 1 , wherein the amount of the energy ray-curable compound having the alkylene oxide chain in the total amount of the energy ray-curable compound is 40% by mass or more. The protective film according to claim 1 or 2, wherein the adhesive composition is characterized in that it does not contain an adhesive component having a weight average molecular weight exceeds 10,000. The protective film is attached to the surface of the transparent conductive film laminating film on which the transparent conductive film is not laminated, and after the transparent conductive film is laminated on the transparent conductive film laminating film, the protective film is peeled off at any stage. The protective film as described in any one of Claims 1-3 characterized by these. On the side where the transparent conductive film in the transparent conductive film laminated film is not laminated is a hard coat layer is formed, the protective film, according to claim 4, characterized in that it is affixed to the hard coat layer Protective film. It is a manufacturing method of the protective film as described in any one of Claims 1-5 ,
On one surface of the substrate, a coating solution containing the adhesive composition is applied and dried to form a coating layer of the adhesive composition,
The manufacturing method of the protective film characterized by irradiating an energy ray with respect to the said application layer, hardening the said application layer, and forming an adhesive layer. The method for producing a protective film according to claim 6 , wherein the application layer is irradiated with energy rays in the presence of oxygen. A transparent conductive film laminating film;
A transparent conductive film with a protective film, comprising the protective film according to any one of claims 1 to 5 , which is attached to a surface of the transparent conductive film lamination film on which the transparent conductive film is not laminated. Film for film lamination.

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