JP6823919B2 - Optical film and its manufacturing method - Google Patents

Description

The present invention relates to an optical film having a cured product layer of a curable composition and a method for producing the same.

Liquid crystal display devices are rapidly expanding into the market for watches, mobile phones, PDAs, notebook computers, personal computer monitors, DVD players, TVs, and the like. The liquid crystal display device visualizes the polarization state due to switching of the liquid crystal, and a polarizer is used because of the display principle. In particular, applications such as TVs are required to have higher brightness, higher contrast, and a wider viewing angle, and polarizing films are also required to have higher transmittance, higher degree of polarization, and higher color reproducibility.

Optical films typified by the polarizing film include, for example, those laminated by adhering a plurality of optical films and those in which the surface of the optical film is treated. Such adhesive treatment and surface treatment include By applying a curable composition or the like and curing it, an adhesive layer, a surface treatment layer, or the like is often formed. In these cases, controlling the thickness of the adhesive layer, the surface treatment layer, etc. is very important in consideration of the physical characteristics and appearance of the optical film.

In Patent Document 1 below, in order to evaluate the adhesiveness of the polarizing film, a cutter knife is used to make a cut only in the transparent protective film constituting the polarizing film, and whether or not the transparent protective film can be peeled off from the cut portion. It is indirectly confirmed whether or not the adhesive layer has a sufficient thickness by evaluating. However, such an evaluation is a so-called destructive inspection, which cannot be easily performed, and the thickness of the target cured product layer cannot be measured more accurately.

Japanese Unexamined Patent Publication No. 2008-80984

The present invention provides an optical film having a cured product layer of a curable composition, and an optical film and a manufacturing method capable of easily and accurately measuring the thickness of the cured product layer of the curable composition by non-destructive inspection. There is.

The above problem can be solved by the following configuration. That is, the present invention includes an optical film having a cured product layer of a curable composition, wherein the curable composition contains a light emitting material having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm. It relates to an optical film, which is characterized in that.

In the optical film, it is preferable that the curable composition contains an active energy ray-curable component.

In the optical film, when the total amount of the curable composition is 100 parts by mass, the content of the light emitting material is preferably 0.01 to 10 parts by mass.

In the optical film, the luminescent material is preferably coumarin and a derivative thereof, and more preferably the coumarin derivative has a diethylamino group.

In the optical film, it is preferable that the optical film is a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizer via an adhesive layer composed of a cured product layer of a curable composition. It is more preferable that the thickness of the adhesive layer is 3 μm or less.

Further, the present invention is a method for producing an optical film having a cured product layer of a curable composition, which comprises a coating step of applying the curable composition to at least one surface of the optical film, and the curing. An optical film comprising a cured product layer forming step of forming a cured product layer by curing the sex composition, and further including a step of measuring the thickness of the cured product layer after the cured product layer forming step. It is preferable to further include a step of measuring the coating thickness of the curable composition after the coating step.

Further, in the method for producing an optical film according to the present invention, the optical film is laminated with a transparent protective film on at least one surface of a polarizer via an adhesive layer composed of a cured product layer of a curable composition. A method for producing an optical film which is a polarizing film, wherein a coating step of applying the curable composition to at least one surface of the polarizer and the transparent protective film, and the polarizer and the transparent protective film. After the bonding step, the bonding step includes a bonding step of bonding the polarizer and the transparent protective film via the adhesive layer obtained by curing the curable composition. It is preferable to further include a step of measuring the thickness of the adhesive layer, and more preferably include a step of measuring the thickness of the curable composition after the coating step or the bonding step and before curing. preferable.

Optical films are often laminated for the purpose of exhibiting various functions, and are interlayer-bonded or surface-treated on the outermost layer via a cured product layer formed by applying and curing a curable composition. May be given. Therefore, the thickness of the formed cured product layer is an important factor that affects the adhesiveness and appearance of each layer, and its thickness control is important. Examples of the method for confirming the thickness of the cured product layer include a method of observing the cross section of the optical film with a scanning electron microscope (SEM) or a transmission electron microscope (TEM), and these are destructive inspections. There is a drawback that it takes time to measure the thickness. Further, even if an attempt is made to measure with a dial gauge or the like, there is a problem in its accuracy, especially when measuring a thickness of about several μm. On the other hand, a method of measuring the thickness of the cured product layer of the optical film in-line during the manufacturing process using a non-contact optical meter is also conceivable, but when the refractive index of the optical film and the cured product layer are close, the thickness is determined. It cannot be measured accurately.

On the other hand, in the optical film according to the present invention, the cured product layer is formed by a cured product layer containing a light emitting material having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm. Therefore, when the light having a specific wavelength is irradiated, the amount of light emitted differs greatly between the optical film and the cured product layer. Further, for example, when the optical film is irradiated with light perpendicularly, the amount of light emitted from the cured product layer is proportional to the content of the light emitting material contained in the cured product layer, that is, the thickness of the cured product layer. Therefore, after measuring the light emission amount of the cured product layer having an arbitrary thickness in advance, the thickness is accurately measured by, for example, SEM, TEM, etc., and a calibration curve showing the relationship between the thickness of the cured product layer and the light emission amount is created. Therefore, at the manufacturing site, the thickness of the cured product layer can be accurately measured by measuring only the amount of light emitted from the cured product layer in-line.

In the method for producing an optical film according to the present invention, since the thickness of the cured product layer can be measured in-line as described above, the optical film can be produced in a state where the thickness of the cured product layer is accurately controlled. In particular, by applying the curable composition to the optical film and then measuring the coating thickness thereof, the optical film can be produced in a state where the thickness of the formed cured product layer is more accurately controlled.

The optical film according to the present invention is an optical film having a cured product layer of a curable composition, and the curable composition emits light having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm. Including materials.

<Luminescent material>
The curable composition used in the present invention contains a light emitting material having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm. In the present invention, the "light emitting material" means a substance that emits light of 420 nm to 480 nm when irradiated with light of 365 nm, and further, in the present invention, a light emitting material having a molar extinction coefficient within the above range. use. The upper limit of the molar extinction coefficient of the luminescent material used is not particularly limited, and examples thereof include 100,000 (L / mol · cm) or less, and further 50,000 (L / mol · cm) or less.

Examples of the light emitting material used in the present invention include triazole-based, phthalimide-based, virazolone-based, stillben-based, oxazole-based, naphthalimide-based compounds, rhodamine-based compounds, benzimidazole-based compounds, thiophene-based compounds, and coumarin-based compounds. .. These may be used alone or in combination of two or more. Among these, coumarin and its derivatives are preferable from the viewpoint of improving the solubility in the curable composition. Alternatively, a stilbene compound is also preferable because it can be added to the curable composition as it is as an aqueous solution and is excellent in handleability.

Coumarin derivative is a derivative of the organic compound represented by the chemical formula _{(C 9 H 6 O 2)} , may have an aromatic ring and / or an organic group at any position on the heterocyclic ring. Examples of the organic group include an aliphatic hydrocarbon group, an aryl group, or a heterocyclic group which may have a substituent, and examples of the aliphatic hydrocarbon group include a substituent having 1 to 20 carbon atoms or a substituent. Examples thereof include a linear or branched alkyl group which may have a hetero atom, a cyclic alkyl group which may have a substituent having 3 to 20 carbon atoms or a hetero atom, an alkenyl group having 2 to 20 carbon atoms, and an aryl. Examples of the group include a phenyl group which may have a substituent or a hetero atom having 6 to 20 carbon atoms, a naphthyl group which may have a substituent or a hetero atom having 10 to 20 carbon atoms, and the like. Examples of the group include a 5- or 6-membered ring group which may have a substituent and contains at least one hetero atom. These may be connected to each other to form a ring. The coumarin derivative having a diethylamino group as the organic group is preferable because it has a high molar extinction coefficient and excellent luminescence characteristics even in a small amount.

Examples of the coumarin derivative include 7 {[4-chloro-6- (diethylamino) -s-triazine-2-yl] amino} -7-triazinylamino-3-phenyl-coumarin, 8-amino-4-marin. Methylcoumarin, 7-diethyldiamino-4-methylcoumarin, 3-cyano-7-hydrocoumarin, 7-hydroxycoumarin-3-carboxylic acid, 6,8-difluoro-7-hydroxy-4-methylcoumarin, 7-amino -4-Methylcoumarin and the like can be mentioned.

Examples of the stilbene compound include 4,4'-bis (diphenyltriazinyl) stilbene and 4,4'-bis (benzoxazole-2-yl) stilbene. Examples of the naphthalimide-based compound include N-methyl-5-methoxynaphthalimide and the like. Examples of the rhodamine-based compound include rhodamine B and rhodamine 6G. Examples of the thiophene compound include 2,5-bis (5'-t-butylbenzoxazolyl-2') thiophene and 2,5-bis (6,6'-bis (tert-butyl) -benzoxazole. -2-Il) Thiophene and the like.

Some polymerization initiators used to cure the curable composition radiate fluorescence when irradiated with active energy rays. However, the intensity of fluorescence emitted from the polymerization initiator (emission amount) is considerably low, and even if the polymerization initiator is blended in the curable composition, the amount of luminescence when irradiated with light is the thickness of the cured product layer. Is almost not proportional to. Further, the fluorescence intensity emitted from the polymerization initiator changes depending on its chemical state, but the polymerization initiator is decomposed and consumed with the generation of radicals, so that the amount of light emitted decreases with time. Therefore, in the present invention, it is preferable to use a stable (non-consumed) light emitting material as the light emitting material, and particularly stable coumarin and its derivative are preferable. In the present invention, there is no particular problem that the curable composition contains a polymerization initiator, and it is preferable that the curable composition contains the above-mentioned light emitting material preferably exemplified in addition to the polymerization initiator.

The content of the light emitting material in the curable composition is preferably 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, when the total amount of the curable composition is 100 parts by mass. More preferably. If the content of the luminescent material in the curable composition is too small, it may not be possible to obtain the luminescent amount required for detecting the thickness of the cured product layer. If the content is too large, the curable composition Insoluble components of the light emitting material may be generated inside, or the optical properties and adhesive properties may be adversely affected.

Next, the curable composition used in the present invention will be described below.

<Curable composition>
In the present invention, a curable composition is used to form a cured product layer. Examples of the cured product layer of the optical film include an adhesive layer, an adhesive layer, and a surface treatment layer. Hereinafter, as examples of the curable composition, an adhesive composition for forming an adhesive layer and an adhesive composition for forming an adhesive layer will be described. These are not particularly limited as long as they are optically transparent, and various forms such as water-based, solvent-based, hot-melt-based, and radical-curing type are used. When producing a transparent conductive laminate or a polarizing film as an optical film, a transparent curable adhesive composition is suitable.

<Adhesive composition>
As the adhesive composition, for example, a radical curable adhesive composition is preferably used. Examples of the radical curable adhesive composition include active energy ray-curable adhesive compositions containing an active energy ray-curable component, such as an electron beam curable type, an ultraviolet curable type, and a visible light curable type. In particular, an active energy ray-curable adhesive composition that can be cured in a short time is preferable, and an ultraviolet curable type or visible light curable type adhesive composition that can be cured with low energy is preferable.

The ultraviolet curable adhesive composition can be broadly classified into a radical polymerization curable adhesive and a cationic polymerization adhesive. In addition, the radical polymerization curable adhesive composition can be used as a thermosetting adhesive.

Typical curable components of the radical polymerization curable adhesive composition include active energy ray-curable components, and examples thereof include a compound having a (meth) acryloyl group and a compound having a vinyl group. These curable components can be either monofunctional or bifunctional or higher. Further, these curable components may be used alone or in combination of two or more. As these curable components, for example, compounds having a (meth) acryloyl group are suitable.

Specific examples of the compound having a (meth) acryloyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-2-nitro. Propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) Acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , 4-Methyl-2-propylpentyl (meth) acrylate, n-octadecyl (meth) acrylate and other (meth) acrylic acid (1-20 carbon atoms) alkyl esters.

Examples of the compound having a (meth) acryloyl group include cycloalkyl (meth) acrylate (for example, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.) and aralkyl (meth) acrylate (for example, benzyl (meth)). (Acrylate, etc.), Polycyclic (meth) acrylate (eg, 2-isobornyl (meth) acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl -2-Norbornylmethyl (meth) acrylate, etc.), hydroxyl group-containing (meth) acrylic acid esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl) -Butyl (meth) methacrylate, etc.), alkoxy group- or phenoxy group-containing (meth) acrylic acid esters (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate , 3-methoxybutyl (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, etc.), epoxy group-containing (meth) acrylic acid esters (for example, glycidyl (meth) acrylate, etc.), halogen-containing (Meta) acrylic acid esters (eg, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl) Examples thereof include (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate), alkylaminoalkyl (meth) acrylate (for example, dimethylaminoethyl (meth) acrylate) and the like.

Examples of the compound having a (meth) acryloyl group other than the above include amide group-containing monomers such as hydroxyethyl acrylamide, N-methylol acrylamide, N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, and (meth) acrylamide. Be done. In addition, nitrogen-containing monomers such as acryloyl morpholine can be mentioned.

Further, as the curable component of the radical polymerization curable adhesive composition, a compound having a plurality of polymerizable double bonds such as a (meth) acryloyl group and a vinyl group can be exemplified, and the compound is crosslinked. It can also be mixed with the adhesive component as a component. Examples of the curable component that becomes such a cross-linking component include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecanedimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO. Modified diglycerin tetraacrylate, Aronix M-220 (manufactured by Toa Synthetic Co., Ltd.), Light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), Light acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.) Examples thereof include SR-531 (manufactured by Sartomer) and CD-536 (manufactured by Sartomer). Further, if necessary, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate-based monomers and the like can be mentioned.

The radical polymerization curable adhesive composition contains the curable component, and in addition to the component, a radical polymerization initiator is added depending on the type of curing. When the adhesive composition is used in an electron beam curable type, it is not particularly necessary to include a radical polymerization initiator in the adhesive composition, but when it is used in an ultraviolet curable type or a thermosetting type, it is used. , A radical polymerization initiator is used. The amount of the radical polymerization initiator used is usually about 0.1 to 10 parts by mass, preferably 0.5 to 3 parts by mass, per 100 parts by mass of the curable component. Further, if necessary, a photosensitizer that increases the curing speed and sensitivity of an electron beam represented by a carbonyl compound or the like can be added to the radical polymerization curing type adhesive. The amount of the photosensitizer used is usually about 0.001 to 10 parts by mass, preferably 0.01 to 3 parts by mass, per 100 parts by mass of the curable component.

Examples of the curable component of the cationic polymerization-curable adhesive composition include compounds having an epoxy group or an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. Preferred epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring in the molecule, or at least two epoxy groups in the molecule, at least one of which has an alicyclic ring. An example is a compound formed between two adjacent carbon atoms constituting the compound.

The adhesive composition may contain additives as appropriate, if necessary. Examples of additives include silane coupling agents, coupling agents such as titanium coupling agents, adhesion promoters typified by ethylene oxide, additives that improve wettability with transparent films, acryloxy group compounds and hydrocarbons. Additives that improve mechanical strength and workability, such as (natural and synthetic resins), UV absorbers, antioxidants, dyes, processing aids, ion trapping agents, antioxidants, tackifiers, Examples thereof include fillers (other than metal compound fillers), plasticizers, leveling agents, foaming inhibitors, anti-static cracks, heat-resistant stabilizers, and stabilizers such as hydrolysis-resistant stabilizers.

The radical polymerization curable adhesive composition can be used in an electron beam curable type or an ultraviolet curable type.

In the electron beam curing type, any appropriate conditions can be adopted as the electron beam irradiation conditions as long as the radical polymerization curing type adhesive composition can be cured. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and curing may be insufficient. If the acceleration voltage exceeds 300 kV, the penetrating power through the sample is too strong and damages the transparent protective film and the polarizer. May be given. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive is insufficiently cured, and when it exceeds 100 kGy, the transparent protective film and the polarizer are damaged, the mechanical strength is lowered and yellowing occurs, and the predetermined optical characteristics are obtained. I can't.

The electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under the condition that a small amount of oxygen is introduced. Depending on the material of the transparent protective film, by appropriately introducing oxygen, oxygen inhibition can be caused on the surface of the transparent protective film that is first hit by the electron beam, and damage to the transparent protective film can be prevented, only for the adhesive. The electron beam can be efficiently irradiated.

On the other hand, in the ultraviolet curable type, when a transparent protective film imparted with an ultraviolet absorbing ability is used, light having a wavelength shorter than about 380 nm is absorbed, so that light having a wavelength shorter than 380 nm is used in the active energy ray-curable adhesive composition. Since it does not reach, it does not contribute to the polymerization reaction. Further, the light having a wavelength shorter than 380 nm absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curl and wrinkles of the polarizing film. Therefore, when the ultraviolet curable type is adopted in the present invention, it is preferable to use a device that does not emit light having a wavelength shorter than 380 nm as the ultraviolet generator, and more specifically, the integrated illuminance and wavelength in the wavelength range of 380 to 440 nm. The ratio to the integrated illuminance in the range of 250 to 370 nm is preferably 100: 0 to 100: 50, and more preferably 100: 0 to 100:40. As ultraviolet rays satisfying such a relationship of integrated illuminance, gallium-filled metal halide lamps and LED light sources that emit light in a wavelength range of 380 to 440 nm are preferable. Alternatively, use low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excima laser or sunlight as the light source. It is also possible to block light having a wavelength shorter than 380 nm by using a bandpass filter.

A water-based adhesive composition can also be used as the curable composition for forming the adhesive layer. Examples of the water-based adhesive composition include vinyl polymer-based, gelatin-based, vinyl-based latex-based, polyurethane-based, isocyanate-based, polyester-based, and epoxy-based. The adhesive layer made of such an aqueous adhesive composition can be formed as a coating dry layer of an aqueous solution or the like, but when preparing the aqueous solution, a cross-linking agent, other additives, acids or the like may be used as necessary. A catalyst can also be blended.

As the water-based adhesive composition, it is preferable to use an adhesive containing a vinyl polymer or the like, and as the vinyl polymer, a polyvinyl alcohol-based resin is preferable. Further, as the polyvinyl alcohol-based resin, an adhesive containing a polyvinyl alcohol-based resin having an acetoacetyl group is more preferable from the viewpoint of improving durability. Further, as the cross-linking agent that can be blended with the polyvinyl alcohol-based resin, a compound having at least two functional groups reactive with the polyvinyl alcohol-based resin can be preferably used. For example, boric acid, borax, carboxylic acid compounds, alkyldiamines; isocyanates; epoxys; monoaldehydes; dialdehydes; amino-formaldehyde resins; and divalent metals, or salts of trivalent metals and their oxides. Can be mentioned.

When the adhesive layer is formed by using the curable composition, the thickness thereof is preferably 5 μm or less. It is more preferably 3 μm or less, still more preferably 1 μm or less. As the lower limit of the thickness of the adhesive layer, for example, 0.01 μm or more, further 0.1 μm or more can be exemplified.

<Adhesive composition>
Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive composition, for example, rubber-based pressure-sensitive adhesive, acrylic-based pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, vinyl alkyl ether-based pressure-sensitive adhesive, and polyvinylpyrrolidone-based pressure-sensitive adhesive. , Polyacrylamide-based adhesives, cellulose-based adhesives and the like. A sticky base polymer is selected according to the type of the pressure-sensitive adhesive composition. Among the pressure-sensitive adhesive compositions, the acrylic pressure-sensitive adhesive composition is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesiveness, and is excellent in weather resistance and heat resistance. Is preferably used.

The optical film of the present invention is produced by the following production method;
A method for producing an optical film having a cured product layer of a curable composition.
A coating process in which the curable composition is applied to at least one surface of the optical film,
Including a step of forming a cured product layer which forms a cured product layer by curing the curable composition.
It can be produced by a method for producing an optical film, which further includes a step of measuring the thickness of the cured product layer after the cured product layer forming step. In particular, when the step of measuring the coating thickness of the curable composition is further included after the coating step, the optical film can be manufactured in a state where the thickness of the formed cured product layer is more accurately controlled. ..

The method for applying the curable composition is appropriately selected depending on the viscosity of the curable composition and the desired thickness. For example, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, etc. Examples include die coaters, bar coaters, and rod coaters. The viscosity of the curable composition used in the present invention is preferably 3 to 100 mPa · s, more preferably 5 to 50 mPa · s, and most preferably 10 to 30 mPa · s. If the viscosity of the curable composition is high, the surface smoothness after coating is poor and the appearance is poor, which is not preferable. The curable composition used in the present invention can be applied by heating or cooling the composition to adjust the viscosity to a preferable range.

The polarizer and the transparent protective film are bonded to each other via the curable composition coated as described above. The polarizer and the transparent protective film can be bonded by a roll laminator or the like.

In the present invention, the type of the optical film is not particularly limited, but the optical film is preferably a transparent protective film on at least one surface of the polarizer via an adhesive layer composed of a cured product layer of the curable composition. A polarizing film in which is laminated is mentioned. Hereinafter, a polarizing film will be described as an example of the optical film.

In the present invention, the polarizing film is produced by the following manufacturing method;
A coating process in which the curable composition is applied to at least one surface of the polarizer and the transparent protective film.
The bonding process of bonding the polarizer and the transparent protective film,
Including an adhesive step of adhering the polarizer and the transparent protective film via an adhesive layer obtained by curing the curable composition.
It can be manufactured by a method for manufacturing an optical film, which further includes a step of measuring the thickness of the adhesive layer after the bonding step. In particular, when the step of measuring the thickness of the curable composition after the coating step or the bonding step and before curing is further included, the optical layer is optically controlled in a state where the thickness of the cured product layer to be formed is more accurately controlled. Films can be manufactured.

When an active energy ray-curable resin composition is used as the curable composition, the active energy ray (electron beam, ultraviolet rays, visible light, etc.) is irradiated after adhering the polarizer and the transparent protective film in the bonding step. Then, the active energy ray-curable resin composition is cured to form an adhesive layer. The irradiation direction of the active energy beam (electron beam, ultraviolet ray, visible light, etc.) can be any suitable direction. Preferably, the irradiation is performed from the transparent protective film side. When irradiated from the polarizer side, the polarizer may be deteriorated by active energy rays (electron beam, ultraviolet rays, visible light, etc.).

In the polarizing film manufacturing process, as a method of measuring the thickness of the adhesive layer in-line by measuring only the amount of light emitted from the adhesive layer, for example, in a polarizing film manufacturing line, light having a predetermined wavelength, for example, a wavelength of 365 nm A method of irradiating the film surface with light having the above-mentioned light in a direction perpendicular to the film surface and measuring the amount of light emitted (fluorescence amount) of the light of 420 nm to 480 nm emitted at that time using a fluorescence measuring device. Examples of such a fluorescence measuring device include the fluorescence measuring device manufactured by Sentec Co., Ltd. described in JP-A-2011-145191.

The polarizer and / or the transparent protective film may be surface-modified before applying the active energy ray-curable adhesive composition. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

In the polarizing film, the polarizer and the transparent protective film are preferably bonded to each other via an adhesive layer formed by a cured product layer of the radical polymerization curable adhesive composition. An easy-adhesion layer can be provided between the transparent protective film and the film. The easy-adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based material, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to form the easy-adhesion layer. Specifically, a tackifier, an ultraviolet absorber, an antioxidant, a stabilizer such as a heat-resistant stabilizer, or the like may be used.

The easy-adhesive layer is formed by applying a material for forming the easy-adhesive layer onto a film by a known technique and drying it. The material for forming the easy-adhesion layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of application, and the like. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. A plurality of easy-adhesive layers can be provided, but even in this case, it is preferable that the total thickness of the easy-adhesive layers is within the above range.

The polarizer is not particularly limited, and various polarizers can be used. As the polarizer, for example, a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene / vinyl acetate copolymerization system partially saponified film, and two colors such as iodine and a bicolor dye are used. Examples thereof include a uniaxially stretched film obtained by adsorbing a sex material, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times its original length. If necessary, it can be immersed in an aqueous solution such as boric acid or potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. In addition to being able to clean the surface of the polyvinyl alcohol film and blocking inhibitors by washing the polyvinyl alcohol film with water, it also has the effect of preventing non-uniformity such as uneven dyeing by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, as the polarizer, a thin polarizer having a thickness of 10 μm or less can be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. It is preferable that such a thin polarizing element has less unevenness in thickness, is excellent in visibility, is excellent in durability because there is little dimensional change, and can be made thinner as a polarizing film.

Typical examples of the thin polarizing element include JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, PCT / JP2010 / 00146, or Japanese Patent Application No. 2010-. Examples thereof include the thin polarizer described in the specification of No. 269002 and the specification of Japanese Patent Application No. 2010-263692. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin base material for stretching in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

The thin polarizing element can be stretched at a high magnification and the polarization performance can be improved even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing, according to WO2010 / 100917 Brochure, PCT / It is preferably obtained by a production method including a step of stretching in an aqueous boric acid solution as described in JP2010 / 00460, or in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692, particularly preferably. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in an aqueous boric acid solution described in Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692.

The thin and high-performance polarizer described in the above description of PCT / JP2010 / 00160 is a thin PVA-based resin having a dichroic substance oriented and having a thickness of 7 μm or less, which is integrally formed on a resin base material. It is a high-performance polarizer and has optical characteristics such as a single transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

In the thin high-performance polarizer, a PVA-based resin layer is formed by applying and drying a PVA-based resin on a resin base material having a thickness of at least 20 μm, and the generated PVA-based resin layer is used as a dyeing solution for a bicolor substance. The PVA-based resin layer on which the bicolorous substance is adsorbed is adsorbed on the PVA-based resin layer by immersing the PVA-based resin layer in an aqueous boric acid solution, and the total draw ratio is increased integrally with the resin base material. It can be produced by stretching so as to be 5 times or more of.

Further, it is a method for producing a laminated film containing a thin and highly functional polarizer in which a bicolor substance is oriented, and contains a resin base material having a thickness of at least 20 μm and a PVA-based resin on one side of the resin base material. The laminate containing a step of producing a laminate film containing a PVA-based resin layer formed by applying and drying an aqueous solution, and a PVA-based resin layer formed on one side of the resin base material and the resin base material. A step of adsorbing a bicolor substance on a PVA-based resin layer contained in a laminated film by immersing the film in a dyeing solution containing a bicolor substance, and a PVA-based resin adsorbing the bicolor substance. The step of stretching the laminated film containing the layer so that the total draw ratio is 5 times or more of the original length in the boric acid aqueous solution, and the PVA-based resin layer on which the bicolor substance is adsorbed are the resin base material. The thickness is 7 μm or less, the single-unit permeability is 42.0% or more, and the degree of polarization is 99, which is composed of a PVA-based resin layer in which a bicolor substance is oriented on one side of the resin base material. The thin and highly functional polarizer can be produced by including the step of producing a laminated film obtained by forming a thin and highly functional polarizer having an optical characteristic of .95% or more.

The above-mentioned Japanese Patent Application No. 2010-269002 and Japanese Patent Application No. 2010-263692 are thin polarizers of continuous web made of a PVA-based resin in which a dichroic substance is oriented, and are amorphous esters. A laminate containing a PVA-based resin layer formed on a based thermoplastic resin base material is stretched in a two-step stretching step consisting of aerial auxiliary stretching and boric acid water stretching to have a thickness of 10 μm or less. Is. In such a thin polarizer, when the simple substance transmittance is T and the degree of polarization is P, P>-(100.929T-42.4-1) × 100 (where T <42.3), and P ≧ 99. It is preferable that the material has optical characteristics that satisfy the condition of .9 (however, T ≧ 42.3).

Specifically, the thin polarizer is a stretching intermediate composed of a PVA-based resin layer oriented by high-temperature stretching in the air with respect to a PVA-based resin layer formed on a continuous web amorphous ester-based thermoplastic resin base material. Colored intermediate formation consisting of a PVA-based resin layer in which a dichroic substance (preferably iodine or a mixture of iodine and an organic dye) is oriented by a step of producing a product and adsorption of the dichroic substance to the stretching intermediate product. A thin polarizer including a step of producing a substance and a step of producing a polarizer composed of a PVA-based resin layer in which a dichroic substance is oriented by stretching in boric acid with respect to a colored intermediate product and having a thickness of 10 μm or less. It can be manufactured by a manufacturing method.

In this production method, the total draw ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material by high-temperature stretching in the air and stretching in water boric acid is set to 5 times or more. desirable. The liquid temperature of the boric acid aqueous solution for stretching in boric acid water can be 60 ° C. or higher. Before stretching the colored intermediate product in the boric acid aqueous solution, it is desirable to insolubilize the colored intermediate product. In that case, the colored intermediate product is added to the boric acid aqueous solution whose liquid temperature does not exceed 40 ° C. It is desirable to do this by immersing. The amorphous ester-based thermoplastic resin base material is an amorphous polyethylene containing a copolymerized polyethylene terephthalate copolymerized with isophthalic acid, a copolymerized polyethylene terephthalate copolymerized with cyclohexanedimethanol, or another copolymerized polyethylene terephthalate. It can be terephthalate, preferably made of a transparent resin, and its thickness can be 7 times or more the thickness of the PVA-based resin layer to be formed. The stretching ratio of the high temperature stretching in the air is preferably 3.5 times or less, and the stretching temperature of the high temperature stretching in the air is preferably equal to or higher than the glass transition temperature of the PVA-based resin, specifically in the range of 95 ° C to 150 ° C. When high-temperature stretching in the air is performed by free-end uniaxial stretching, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material is preferably 5 times or more and 7.5 times or less. .. Further, when high-temperature stretching in the air is performed by uniaxial stretching at a fixed end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin base material is 5 times or more and 8.5 times or less. Is preferable.
More specifically, a thin polarizer can be manufactured by the following method.

A continuous web substrate of isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) obtained by copolymerizing 6 mol% of isophthalic acid is prepared. The glass transition temperature of amorphous PET is 75 ° C. A laminate composed of an amorphous PET substrate of a continuous web and a polyvinyl alcohol (PVA) layer is prepared as follows. By the way, the glass transition temperature of PVA is 80 ° C.

An amorphous PET substrate having a thickness of 200 μm and a PVA aqueous solution having a degree of polymerization of 1000 or more and a PVA powder having a degree of polymerization of 99% or more dissolved in water and having a concentration of 4 to 5% are prepared. Next, a PVA aqueous solution is applied to a 200 μm-thick amorphous PET base material and dried at a temperature of 50 to 60 ° C. to obtain a laminate in which a 7 μm-thick PVA layer is formed on the amorphous PET base material. ..

A thin, high-performance polarizer having a thickness of 3 μm is produced from a laminate containing a PVA layer having a thickness of 7 μm through the following steps including a two-step stretching step of auxiliary stretching in the air and stretching in boric acid in water. By the first-stage aerial auxiliary stretching step, the laminate containing the 7 μm-thick PVA layer is integrally stretched with the amorphous PET substrate to produce a stretched laminate containing the 5 μm-thick PVA layer. Specifically, this stretched laminate is subjected to a stretching device equipped in an oven set to a stretching temperature environment of 130 ° C. to obtain a stretching ratio of 1.8 times by subjecting the laminated body containing a 7 μm-thick PVA layer to a stretching device. It is stretched uniaxially at the free end. By this stretching treatment, the PVA layer contained in the stretched laminate is changed into a 5 μm-thick PVA layer in which PVA molecules are oriented.

Next, a dyeing step produces a colored laminate in which iodine is adsorbed on a 5 μm-thick PVA layer in which PVA molecules are oriented. Specifically, in this colored laminate, the stretched laminate is made into a dyeing solution containing iodine and potassium iodide at a liquid temperature of 30 ° C., and the single transmittance of the PVA layer constituting the high-performance polarizing element finally produced. By soaking for any time so that is 40-44%
Iodine is adsorbed on the PVA layer contained in the stretched laminate. In this step, the dyeing solution uses water as a solvent and has an iodine concentration in the range of 0.12 to 0.30% by weight and a potassium iodide concentration in the range of 0.7 to 2.1% by weight. The ratio of iodine to potassium iodide concentrations is 1: 7. By the way, potassium iodide is required to dissolve iodine in water. More specifically, by immersing the stretched laminate in a staining solution having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight for 60 seconds, iodine was added to a 5 μm-thick PVA layer in which PVA molecules were oriented. To produce a colored laminate in which iodine is adsorbed.

Further, by the second step of stretching in boric acid in water, the colored laminate is further stretched integrally with the amorphous PET substrate to generate an optical film laminate containing a PVA layer constituting a high-performance polarizer having a thickness of 3 μm. To do. Specifically, this optical film laminate is stretched by subjecting the colored laminate to a stretching device installed in a processing device set in a boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C. containing boric acid and potassium iodide. It is stretched uniaxially at the free end so that the magnification is 3.3 times. More specifically, the liquid temperature of the boric acid aqueous solution is 65 ° C. It also has a boric acid content of 4 parts by mass with respect to 100 parts by mass of water and a potassium iodide content of 5 parts by mass with respect to 100 parts by mass of water. In this step, the colored laminate having an adjusted iodine adsorption amount is first immersed in a boric acid aqueous solution for 5 to 10 seconds. After that, the colored laminate is passed as it is between a plurality of sets of rolls having different peripheral speeds, which is a stretching device deployed in the processing device, and the stretching ratio is freely increased to 3.3 times over 30 to 90 seconds. Stretch uniaxially. By this stretching treatment, the PVA layer contained in the colored laminate is changed into a 3 μm-thick PVA layer in which the adsorbed iodine is highly oriented in one direction as a polyiodine ion complex. This PVA layer constitutes a high-performance polarizer of an optical film laminate.

Although not an essential step in the production of the optical film laminate, the optical film laminate was taken out from the boric acid aqueous solution by the cleaning step and adhered to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate. It is preferable to wash boric acid with an aqueous solution of potassium iodide. After that, the washed optical film laminate is dried by a drying step with warm air at 60 ° C. The cleaning step is a step for eliminating appearance defects such as boric acid precipitation.

Similarly, although it is not an essential step for producing an optical film laminate, an adhesive is applied to the surface of a 3 μm-thick PVA layer formed on an amorphous PET substrate by a bonding and / or transfer step. However, after the 80 μm-thick triacetyl cellulose film is attached, the amorphous PET substrate can be peeled off and the 3 μm-thick PVA layer can be transferred to the 80 μm-thick triacetyl cellulose film.

[Other processes]
The method for producing a thin polarizer may include other steps in addition to the above steps. Examples of other steps include an insolubilization step, a cross-linking step, a drying (adjustment of water content) step, and the like. Other steps can be performed at any suitable timing. The insolubilization step is typically performed by immersing a PVA-based resin layer in an aqueous boric acid solution. By applying the insolubilization treatment, water resistance can be imparted to the PVA-based resin layer. The concentration of the boric acid aqueous solution is preferably 1 part by mass to 4 parts by mass with respect to 100 parts by mass of water. The liquid temperature of the insolubilizing bath (boric acid aqueous solution) is preferably 20 ° C to 50 ° C. Preferably, the insolubilization step is performed after the laminate is prepared and before the dyeing step and the underwater stretching step. The cross-linking step is typically performed by immersing a PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by subjecting it to a cross-linking treatment. The concentration of the boric acid aqueous solution is preferably 1 part by mass to 4 parts by mass with respect to 100 parts by mass of water. Further, when the cross-linking step is performed after the dyeing step, it is preferable to further add iodide. By blending iodide, elution of iodine adsorbed on the PVA-based resin layer can be suppressed. The blending amount of iodide is preferably 1 part by mass to 5 parts by mass with respect to 100 parts by mass of water. Specific examples of iodide are as described above. The liquid temperature of the cross-linked bath (boric acid aqueous solution) is preferably 20 ° C. to 50 ° C. Preferably, the cross-linking step is performed before the second boric acid water stretching step. In a preferred embodiment, the dyeing step, the cross-linking step, and the second boric acid water stretching step are performed in this order.

As the material for forming the transparent protective film provided on one side or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include based polymers and polystyrene polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamides, imide polymers, and sulfone polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or the above. Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film may contain one or more of any suitable additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a color retardant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. .. When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

Further, as the transparent protective film, a polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain (A), and ( B) Examples thereof include a resin composition containing a thermoplastic resin having a substituted and / or unsubstituted phenyl and a nitrile group in the side chain. Specific examples thereof include a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, problems such as unevenness due to distortion of the polarizing film can be eliminated, and since the moisture permeability is small, they are excellent in humidification durability.

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm in terms of workability such as strength and handleability, and thin layer property. In particular, 20 to 80 μm is preferable, and 30 to 60 μm is more preferable.

When the transparent protective films are provided on both sides of the polarizer, the transparent protective films made of the same polymer material may be used on the front and back sides thereof, or the transparent protective films made of different polymer materials may be used.

A surface treatment layer such as a hard coat layer composed of a cured product layer of the curable composition, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer may be provided on the surface of the transparent protective film to which the polarizer is not adhered. it can.

The polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited, but is used for forming, for example, a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a liquid crystal display device such as a viewing angle compensation film, or the like. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on the polarizing film of the present invention, an elliptically polarizing film or a circularly polarized light in which a retardation plate is further laminated on a polarizing film. A wide viewing angle polarizing film in which a viewing angle compensating film is further laminated on a film or a polarizing film, or a polarizing film in which a brightness improving film is further laminated on a polarizing film is preferable.

An optical film in which the above optical layer is laminated on a polarizing film can also be formed by a method of sequentially and separately laminating in a manufacturing process of a liquid crystal display device or the like, but a pre-laminated optical film is of good quality. It is excellent in stability and assembly work, and has the advantage of improving the manufacturing process of liquid crystal display devices and the like. An appropriate adhesive means such as an adhesive layer can be used for laminating. When adhering the above-mentioned polarizing film and other optical films, their optical axes can be arranged at an appropriate arrangement angle according to a target phase difference characteristic or the like.

An adhesive layer for adhering to other members such as a liquid crystal cell can be provided on the above-mentioned polarizing film or an optical film in which at least one polarizing film is laminated. As the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer, the above-mentioned ones can be used.

The pressure-sensitive adhesive layer can also be provided on one or both sides of a polarizing film or an optical film as a superimposing layer of different compositions or types. Further, when provided on both sides, adhesive layers having different compositions, types and thicknesses can be formed on the front and back surfaces of the polarizing film or the optical film. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to the purpose of use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 1 to 200 μm, and particularly preferably 1 to 100 μm.

The exposed surface of the pressure-sensitive adhesive layer is temporarily covered with a separator for the purpose of preventing contamination until it is put into practical use. This makes it possible to prevent the adhesive layer from coming into contact with the adhesive layer under normal handling conditions. As the separator, except for the above-mentioned thickness condition, for example, an appropriate thin leaf body such as a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a net, a foam sheet or a metal leaf, or a laminate thereof may be used as a silicone-based or long separator. Appropriate conventional ones such as those coated with an appropriate release agent such as chain alkyl type, fluorine type and molybdenum sulfide can be used.

The polarizing film or optical film of the present invention can be preferably used for forming various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, the liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell, a polarizing film or an optical film, and if necessary, components such as a lighting system, and incorporating a drive circuit. There is no particular limitation except that the polarizing film or the optical film according to the invention is used, and the conventional method can be applied. As the liquid crystal cell, any type such as TN type, STN type, and π type can be used.

An appropriate liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is arranged on one side or both sides of the liquid crystal cell, or a lighting system using a backlight or a reflector can be formed. In that case, the polarizing film or optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When polarizing films or optical films are provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, an appropriate component such as a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight is placed in one layer at an appropriate position or Two or more layers can be arranged.

Examples of the present invention will be described below, but the embodiments of the present invention are not limited thereto.

<Molar extinction coefficient>
The method for measuring the molar extinction coefficient is to dissolve the luminescent material in a solvent (preferably methanol), measure the absorbance at a wavelength of 365 nm using a UV-Vis-NIR spectrum meter (Cary 5000) manufactured by Agilent Technologies, and use the following formula. ;
A = εLc
(A is the absorbance, ε is the molar extinction coefficient (mol ^-1 , L, cm ^-1 ), c is the concentration (mol / L) in the solution of the measured object, and L is the optical path length (cm)). ..

Example 1
Compared to the optical film, cellulose triacetate film (manufactured by Fuji Film Co., Ltd.), the light emitting material, 7 {[4-chloro-6- (diethylamino) -s-triazine-2-yl] amino} -7-triage. Apply a 50 wt% ethyl acetate solution of polyvinyl acetate (Gosenil) (Nippon Synthetic Co., Ltd.) containing 0.2 wt% of nylamino-3-phenyl-coumarin (“Hakkol PY1800”; manufactured by Showa Kagaku Kogyo Co., Ltd.) with an applicator. Then, it was dried at 60 ° C. for 20 minutes. After that, light having a wavelength of 365 nm is irradiated in the direction perpendicular to the film surface, and the amount of light emitted (fluorescence amount) of 420 nm to 480 nm emitted at that time is determined by the fluorescence manufactured by Centec Co., Ltd. described in JP2011-145191. It was measured using a measuring device. At this time, the coating thickness was changed to 1 μm, 2 μm, and 3 μm after drying by changing the gauge of the applicator, and an increase or decrease in the amount of light emitted was confirmed. The actual thickness was measured with a dial gauge.

Example 2, Comparative Examples 1 to 7
The same method was used except that the luminescent material was changed to that shown in the table.

In Table 1 and Table 2,
Hakcol P is 8-amino-4-methylcoumarin; manufactured by Showa Chemical Industry Co., Ltd.,
IRGACURE 369 is 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1; manufactured by BASF, Inc.
IRGACURE 1173 is 2-hydroxy-2-methyl-1-phenyl-propane-1-one; manufactured by BASF, Inc.
IRGACURE 651 is 2,2-dimethoxy-1,2-diphenylethane-1-one; manufactured by BASF, Inc.
IRGACURE 784 is a bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium; manufactured by BASF, Inc.
IRGACURE 379 is 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone; manufactured by BASF, Inc.
IRGACURE OXE01 is 1.2-octanedione, 1- [4- (phenylthio)-, 2- (o-benzoyloxime)]; manufactured by BASF, Inc.
IRGACURE OXE02 indicates etanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (o-acetyloxime); manufactured by BASF.

<Evaluation method of 〇 and × regarding the creation of the thickness calibration curve in Tables 1 and 2>
〇: When the thickness of the cured product layer was changed from 1 μm to 3 μm, the amount of light emitted changed by 10 or more. → It was judged that a thickness calibration curve could be created and marked as 〇.
X: When the thickness of the cured product layer was changed from 1 μm to 3 μm, the amount of light emitted did not change by 10 or more. → It was judged that it was impossible to create a thickness calibration curve, and it was marked as ×.

In Examples 1 and 2, the amount of light emitted from the cured product layer is sufficient, and the amount of light emitted changes in proportion to the thickness thereof. Therefore, it can be seen that the thickness can be calculated by measuring the amount of light emitted. On the other hand, in Comparative Examples 1 to 7, since it is a cured product layer of the curable composition containing a polymerization initiator, the amount of light emitted hardly changes even if the thickness changes. Therefore, it can be seen that the thickness of the cured product layer cannot be calculated based on the amount of light emitted.

Example 3

<Making a polarizer>
A polyvinyl alcohol film having an average degree of polymerization of 2400 and a saponification degree of 99.9 mol% and a thickness of 75 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Then, the film was dyed by immersing it in an aqueous solution having a concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) at a concentration of 0.3% and stretching it up to 3.5 times. Then, stretching was carried out in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio was 6 times. After stretching, it was dried in an oven at 40 ° C. for 3 minutes to obtain a PVA-based polarizer (thickness 23 μm).

<Transparent protective film>
Transparent protective film 1: A triacetyl cellulose film having a thickness of 60 μm was used without saponification, corona treatment, or the like.
Transparent protective film 2: A (meth) acrylic resin having a lactone ring structure having a thickness of 40 μm was subjected to corona treatment and used.

<Active energy ray>
Visible light (gallium-filled metal halide lamp) Irradiator: Fusion UV Systems, Inc. Light HAMMER10 bulb: V bulb Peak illuminance: 1600 mW / cm ² , integrated irradiation dose 1000 / mJ / cm ² (wavelength 380-) 440 nm) was used. The illuminance of visible light was measured using a Solar-Check system manufactured by Solarll.

Preparation of active energy ray-curable adhesive composition 3', 4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate ("Ceroxide 2021P"; manufactured by Daicel Co., Ltd.) 5 g, 3-ethyl-3 {[(3-) Ethyl oxetane-3-yl) methoxy] methyl} oxetane ("Aron oxetane OXT221"; manufactured by Toa Synthetic Co., Ltd.) and a photocationic polymerization initiator (triarylsulfonium salt type photoacid generator "CPI-100P"; 1 g (manufactured by San-Apro) and 0.04 g of Hakkol PY-1800, which is a light emitting material, were mixed in a brown screw tube (No. 5) to prepare an active energy ray-curable adhesive composition.

<Manufacturing of polarizing film>
Using an MCD coater (manufactured by Fuji Kikai Kogyo Co., Ltd.), the active energy ray-curable adhesive is applied onto the transparent protective films 1 and 2 so as to have a thickness of 1 μm, 2 μm, and 3 μm. It was pasted on both sides of the surface with a roll machine. After that, the active energy ray-curable adhesive was cured by irradiating the visible light with an active energy ray irradiator on each side from the transparent protective film 1 side, and then dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing element. A polarizing film having a transparent protective film on both sides was obtained. The bonding line speed was 15 m / min. The thickness was measured by observing the cross section SEM.

Example 4, Comparative Examples 8-14
The same method was used except that the luminescent material was changed to that shown in the table.

実施例３および４では、硬化物層の発光量が十分であり、その厚みに比例して発光量が変化することから、発光量を測定することで厚みが計算できることがわかる。一方、比較例８〜１４では、重合開始剤を含有する硬化性組成物の硬化物層であるため、厚みが変化しても発光量がほとんど変化しない。このため、発光量に基づき、硬化物層の厚みが計算できないことがわかる。

In Examples 3 and 4, the amount of light emitted from the cured product layer is sufficient, and the amount of light emitted changes in proportion to the thickness thereof. Therefore, it can be seen that the thickness can be calculated by measuring the amount of light emitted. On the other hand, in Comparative Examples 8 to 14, since the cured product layer is a curable composition containing a polymerization initiator, the amount of light emitted hardly changes even if the thickness changes. Therefore, it can be seen that the thickness of the cured product layer cannot be calculated based on the amount of light emitted.

Claims (7)

A method for producing an optical film having a cured product layer of a curable composition.
A coating process in which the curable composition is applied to at least one surface of the optical film,
Including a cured product layer forming step of forming a cured product layer by curing the curable composition.
After the coating step, the step of measuring the coating thickness of the curable composition is further included.
After the cured product layer forming step further look including the step of measuring the thickness of the cured layer,
A method for producing an optical film, wherein the curable composition contains a luminescent material having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm . The optical film according to claim 1, wherein the optical film is a polarizing film in which a transparent protective film is laminated on at least one surface of a polarizing element via an adhesive layer composed of a cured product layer of the curable composition. It ’s a manufacturing method,
A coating step of applying a curable composition to at least one surface of the polarizer and the transparent protective film, and
The bonding step of bonding the polarizer and the transparent protective film, and
Including an bonding step of adhering the polarizer and the transparent protective film via the adhesive layer obtained by curing the curable composition.
After the coating step, the step of measuring the coating thickness of the curable composition is further included.
After the bonding step further look including the step of measuring the thickness of the adhesive layer,
A method for producing an optical film, wherein the curable composition contains a light emitting material having a molar extinction coefficient of 10000 (L / mol · cm) or more at a wavelength of 365 nm . The method for producing an optical film according to claim 2, wherein the thickness of the adhesive layer is 3 μm or less. The method for producing an optical film according to any one of claims 1 to 3 , wherein the curable composition contains an active energy ray-curable component. The method for producing an optical film according to any one of claims 1 to 4 , wherein the content of the light emitting material is 0.01 to 10 parts by mass when the total amount of the curable composition is 100 parts by mass. The method for producing an optical film according to any one of claims 1 to 5 , wherein the light emitting material is coumarin and a derivative thereof. The method for producing an optical film according to claim 6 , wherein the coumarin derivative has a diethylamino group.