KR20230035223A - Polarizing film, optical film and image display device - Google Patents

Abstract

A polarizing film comprising a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, wherein the adhesive layer is formed of a cured product layer of an adhesive composition, and the adhesive composition assumes that the total amount of monomer components is 100 parts by weight. , containing 25 parts by weight or more of a monomer component having two or more polymerizable functional groups, and after a humidification durability test in which it is exposed to an environment of 65 ° C. - 95% humidity for 1000 hours, it exceeds 3 mm from the cross section and is derived from foreign matter A polarizing film characterized by not having a bright spot. It is preferable that the polarizer contains a metal component that can become a divalent metal cation in water, particularly zinc.

Description

Polarizing film, optical film and image display device

The present invention relates to a polarizing film provided with a polarizer and an adhesive layer adjacent to a polarizer or an optical film other than the polarizer. The polarizing film can form an image display device such as a mobile phone, a car navigation device, a monitor for a personal computer, or a television as an optical film obtained by itself or a laminate thereof.

BACKGROUND OF THE INVENTION In mobile phones, car navigation devices, monitors for personal computers, televisions and the like, liquid crystal display devices are rapidly developing in the market. The liquid crystal display device visualizes the polarization state by switching of the liquid crystal, and a polarizer is used from the display principle. In particular, in applications such as TVs, high brightness, high contrast, and a wide viewing angle are increasingly required, and polarizing films are also increasingly required to have high transmittance, high polarization degree, and high color reproducibility.

As a polarizer, an iodine-based polarizer having a structure in which iodine is adsorbed to, for example, polyvinyl alcohol (hereinafter, simply referred to as "PVA") and stretched is most commonly and widely used because of its high transmittance and high degree of polarization. . In general, what bonded a transparent protective film to both surfaces of a polarizer with the so-called water-system adhesive which melt|dissolved a polyvinyl alcohol-type material in water is used for a polarizing film (patent document 1 below). As the transparent protective film, triacetyl cellulose having high moisture permeability or the like is used. When the said water-system adhesive agent is used (so-called wet lamination), after bonding a polarizer and a transparent protective film together, a drying process is needed.

On the other hand, an active energy ray-curable adhesive has been proposed instead of the above water-based adhesive. Since a drying process is not required when manufacturing a polarizing film using an active energy ray-curable adhesive agent, productivity of a polarizing film can be improved. For example, a radical polymerization type active energy ray-curable adhesive using an N-substituted amide-based monomer as a curable component has been proposed (Patent Document 2 below). The adhesive layer formed using the active energy ray-curable adhesive described in Patent Literature 2 can be sufficiently cleared, for example, in a water resistance test to evaluate the presence or absence of color loss and peeling after immersion in 60 ° C. hot water for 6 hours. However, in recent years, polarizing films are often used not only for mobile applications such as mobile phones but also for in-vehicle image display devices, and in in-vehicle applications it is necessary to satisfy durability tests under higher temperature and higher humidity conditions than for mobile applications.

Japanese Unexamined Patent Publication No. 2001-296427 Japanese Unexamined Patent Publication No. 2012-052000

As a durability test required for a polarizing film used in vehicle applications, there is, for example, a humidification durability test in which exposure is performed in an environment of 65°C - 95% humidity for 1000 hours. Here, as a result of a detailed examination of the appearance state of the polarizing film after the humidification durability test by the present inventor, in particular, a bright spot derived from a white haze-like foreign matter occurred at the end of the polarizing film, and in terms of appearance characteristics I found out that the product is defective. Such a phenomenon was observed for the first time after a durability test under a high-temperature and high-humidity environment, and it was necessary to study diligently in order to solve it anew.

The present invention was developed in view of the above situation, and an object of the present invention is to provide a polarizing film having excellent appearance characteristics by suppressing generation of bright spots derived from foreign matter even after a humidification durability test.

The above problem can be solved by the following configuration. That is, the present invention is a polarizing film comprising a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, wherein the adhesive layer is formed of a cured product layer of an adhesive composition, wherein the adhesive composition is a monomer When the total amount of the components is 100 parts by weight, it contains 25 parts by weight or more of a monomer component having two or more polymerizable functional groups, and after a humidification durability test in which it is exposed to an environment of 65 ° C. - 95% humidity for 1000 hours, from the cross section It relates to a polarizing film characterized in that it does not have a bright spot derived from a foreign material exceeding 3 mm.

In the polarizing film, the adhesive composition preferably contains 40 parts by weight or less of a monomer component having a hydroxyl group, based on 100 parts by weight of the total amount of the monomer components.

In the polarizing film, it is preferable that the polarizer contains a metal component capable of becoming a divalent metal cation in water.

In the polarizing film, the metal component is preferably zinc.

In the polarizing film, the polarizing film has a polarizer, and an optical film is laminated on at least one surface of the polarizer via a water-based adhesive layer, and an adhesive layer is formed on a surface of the optical film opposite to the water-based adhesive layer. It is preferable to provide.

In the polarizing film, it is preferable that the adhesive layer is formed of a layer of a cured product of an active energy ray-curable adhesive composition.

In the polarizing film, when the adhesive layer is formed of a cured product layer of an adhesive composition and the cured product obtained by curing the adhesive composition is immersed in 23°C pure water for 24 hours,

Formula: {(M2−M1)/M1}×100 (%),

However, M1: weight of cured material before immersion, M2: weight of cured material after immersion,

It is preferable that the bulk water absorption represented by is less than 10% by weight.

In addition, the present invention is an image characterized in that the optical film characterized in that at least one polarizing film described in any one of the above is laminated, the polarizing film described in any one of the above, and/or the optical film described above is used. It is about the display device.

In the polarizing film used for vehicle applications, for example, it is required to have excellent appearance characteristics even after a humidification durability test in which exposure is carried out in an environment of 65°C - 95% humidity for 1000 hours. In the polarizing film concerning the present invention, after such a humidification durability test, it is excellent in appearance characteristics in that it does not have a bright spot derived from a foreign material exceeding 3 mm from the cross section.

In particular, even when the polarizing film according to the present invention includes a polarizer containing a metal component capable of becoming a divalent metal cation in water, particularly zinc, the polarizing film has excellent appearance characteristics. Although the reason why this effect is obtained is not clear, the following reasons can be estimated, for example.

In a polarizing film provided with a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, at the time of a humidification durability test, a metal component that can become a divalent metal cation in water, particularly zinc, which the polarizer contains , It moves into the adhesive layer via vapor or dew condensation at the end of the polarizing film. Here, in the adhesive layer, components other than components contained in the adhesive composition as a raw material, for example, oxalic acid exist in an ionized state, but oxalic acid acts as a foreign substance in the adhesive layer unless it is combined with a metal component to form an oxalate. not detected However, at the time of the humidification durability test, when a specific metal component contained in the polarizer is mixed from the end in the adhesive layer, ionized oxalic acid and the metal component are combined, in particular, oxalate is generated at the end in the adhesive layer, and becomes a white bright spot detected as foreign matter. As a result, the appearance characteristics of the polarizing film deteriorate.

In particular, the adhesive layer of the polarizing film according to the present invention is formed of the cured product layer of the adhesive composition, and the adhesive composition is a monomer component having two or more polymerizable functional groups when the total amount of the monomer components is 100 parts by weight By containing 25 parts by weight or more, it is possible to suppress the bonding between ionized oxalic acid and the metal component, and also the movement of oxalate from the polarizing film edge to the inside, particularly at the end portion of the adhesive layer. As a result, the appearance characteristics of the polarizing film are remarkably improved even after the humidification durability test.

The polarizing film according to the present invention is a polarizing film having a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, and after a humidification durability test exposed to an environment of 65° C. to 95% humidity for 1000 hours, cross-section It does not have a bright spot originating from a foreign matter exceeding 3 mm from the . In particular, when the polarizer according to the present invention has an adhesive layer designed so that the bulk water absorption of the cured product layer of the adhesive composition as a raw material is less than 10% by weight, the specific metal component contained in the polarizer is mixed in the adhesive layer from the edge. Even in this case, the binding between the ionized oxalic acid and the metal component and, consequently, the movement of the oxalate from the edge of the polarizing film to the inside is suppressed. As a result, even after the humidification durability test, the appearance characteristics of the polarizing film are particularly improved.

1 is an example of a cross-sectional schematic diagram of a polarizing film according to an embodiment of the present invention.
2 is another example of a cross-sectional schematic diagram of a polarizing film according to an embodiment of the present invention.

1 shows an example of a cross-sectional schematic diagram of a polarizing film according to an embodiment of the present invention. The polarizing film 10 in this embodiment is provided with the adhesive bond layer 5 adjacent to the polarizer 1 and the 1st optical films 4 other than the polarizer 1. More specifically, the polarizer 1 and the first optical film (retardation film) 4 are laminated on at least one surface of the polarizer 1 via the aqueous adhesive layer 2, and the first optical film ( 4) The surface opposite to the water-based adhesive layer 2 is provided with the adhesive layer 5. In particular, in the polarizing film 10 of this embodiment, the second optical film (transparent protective film) 3 is laminated on one surface of the polarizer 1 via the water-based adhesive layer 2, and the polarizer 1 A first optical film (retardation film) 4 is laminated on the other side of the water-based adhesive layer 2, and an adhesive layer 5 is laminated on the first optical film (retardation film) 4. , A third optical film (retardation film) 6 is laminated on the adhesive layer 5. The polarizing film 10 is laminated on an image display cell or the like with a pressure-sensitive adhesive layer 7 further laminated on the third optical film 6, and the pressure-sensitive adhesive layer 7 interposed therebetween.

2 shows another example of a cross-sectional schematic diagram of a polarizing film according to an embodiment of the present invention. The polarizing film 10 in this embodiment is equipped with the polarizer 1 and the adhesive bond layer 5 adjacent to the polarizer 1. More specifically, in the polarizing film 10 of this embodiment, the second optical film (transparent protective film) 3 is laminated on one surface of the polarizer 1 via the water-based adhesive layer 2, The 1st optical film (retardation film) 4 is laminated|stacked on the other surface of the polarizer 1 via the adhesive bond layer 5. In the polarizing film 10, the pressure-sensitive adhesive layer 7 is further laminated on the optical film 4, and the polarizing film 10 is laminated on an image display cell or the like with the pressure-sensitive adhesive layer 7 interposed therebetween.

In the polarizing film shown in FIGS. 1 and 2 , the water-based adhesive layer 2 is an aqueous solution of an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex-based adhesive, or a water-based polyester adhesive (for example, For example, a solid content concentration of 0.5 to 60% by weight) is preferably used. The thickness of the water-based adhesive layer 2 is not particularly limited, but is usually about 0.01 μm to 0.5 μm as a thickness after drying.

In the polarizing film 10 shown in FIGS. 1 and 2 , at the time of the humidification durability test, a metal component that can become a divalent metal cation in water, particularly zinc, which the polarizer 1 contains, is a polarizing film (10 ) moves into the adhesive layer 5 via steam or condensation at the end. Here, in the adhesive layer 5, components other than components contained in the adhesive composition as a raw material, for example, oxalic acid exist in an ionized state, but oxalic acid is not combined with a metal component to form an oxalate, so long as oxalic acid is not present in the adhesive layer. It is not detected as a foreign substance in Here, at the time of the humidification durability test, when a specific metal component contained in the polarizer 10 is mixed in the adhesive layer 5, ionized oxalic acid and the metal component are combined to generate oxalate, which becomes a white bright spot and is detected as a foreign substance However, the polarizing film 10 shown in FIGS. 1 and 2 exceeds 3 mm from the cross section, more preferably 2 mm from the cross section, after a humidification durability test exposed to an environment of 65°C - 95% humidity for 1000 hours. It does not have a bright spot originating from a foreign matter exceeding mm.

Below, each structure of the polarizing film concerning this invention is demonstrated. In the present invention, the polarizing film includes a polarizer and an adhesive layer adjacent to the polarizer or optical films other than the polarizer.

<Polarizer>

As a material of the polyvinyl alcohol-based film applied to the polarizer, polyvinyl alcohol or a derivative thereof is used. Examples of polyvinyl alcohol derivatives include polyvinyl formal and polyvinyl acetal, as well as olefins such as ethylene and propylene, alkyl esters of unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, acrylic and those modified with amide or the like. As for polyvinyl alcohol, what has a degree of polymerization of about 1000 to 10000 and a degree of saponification of about 80 to 100 mol% is generally used.

A polyvinyl alcohol-type film may contain additives, such as a plasticizer. As a plasticizer, a polyol, its condensate, etc. are mentioned, For example, glycerol, diglycerol, triglycerol, ethylene glycol, propylene glycol, polyethylene glycol, etc. are mentioned. The amount of plasticizer used is not particularly limited, but is preferably 20% by weight or less in the polyvinyl alcohol-based film.

In manufacture of the polarizer, a dyeing process in which the polyvinyl alcohol-based film is dyed with iodine, and a stretching process in which the polyvinyl alcohol-based film is stretched in at least one direction are performed. In general, a method of subjecting the polyvinyl alcohol-based film to a series of processes including swelling, dyeing, crosslinking, stretching, water washing and drying processes is employed.

The swelling step is performed, for example, by immersing the polyvinyl alcohol-based film in a swelling bath (water bath). By this treatment, contamination and antiblocking agent on the surface of the polyvinyl alcohol-based film are washed away, and non-uniformity such as dyeing non-uniformity can be prevented by swelling the polyvinyl alcohol-based film. Glycerin, potassium iodide, etc. may be suitably added to the swelling bath. The temperature of the swelling bath is usually about 20 to 60°C, and the immersion time in the swelling bath is usually about 0.1 to 10 minutes.

A dyeing process is performed by immersing a polyvinyl alcohol-type film in an iodine solution, for example. The iodine solution is usually an iodine aqueous solution, and contains iodine and potassium iodide as a solubilizing agent. The iodine concentration is usually about 0.01 to 1% by weight, preferably 0.02 to 0.5% by weight. The potassium iodide concentration is usually about 0.01 to 10% by weight, preferably 0.02 to 8% by weight.

In the iodine dyeing step, the temperature of the iodine solution is usually about 20 to 50°C, preferably 25 to 40°C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds. In the iodine dyeing treatment, conditions such as the concentration of the iodine solution, the immersion temperature and immersion time of the polyvinyl alcohol-based film in the iodine solution are adjusted so that the iodine content and the potassium content in the polyvinyl alcohol-based film fall within the above ranges. desirable.

The crosslinking step is performed, for example, by immersing the polyvinyl alcohol-based film dyed with iodine in a treatment bath containing a crosslinking agent. Any suitable crosslinking agent is employed as the crosslinking agent. Specific examples of the crosslinking agent include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. These are used alone or in combination. Although water is common as a solvent used for the solution of the crosslinking bath, an appropriate amount of an organic solvent having compatibility with water may be added. The crosslinking agent is usually used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the solvent. It is preferable that the solution of the crosslinking bath further contains an auxiliary agent such as iodide. The concentration of the adjuvant is preferably 0.05 to 15% by weight, more preferably 0.5 to 8% by weight. The temperature of the crosslinking bath is usually about 20 to 70°C, preferably 40 to 60°C. The immersion time in the crosslinking bath is usually about 1 second to 15 minutes, preferably 5 seconds to 10 minutes.

The stretching step is a step in which the polyvinyl alcohol-based film is stretched in at least one direction. Generally, the polyvinyl alcohol-based film is uniaxially stretched in the transport direction (longitudinal direction). The stretching method is not particularly limited, and either a wet stretching method or a dry stretching method can be employed. When the wet stretching method is employed, the polyvinyl alcohol-based film is stretched at a predetermined magnification in a treatment bath. As the solution of the stretching bath, a solution in which compounds necessary for various treatments are added in a solvent such as water or an organic solvent (eg ethanol) is preferably used. Examples of the dry stretching method include an inter-roll stretching method, a heated roll stretching method, and a compression stretching method. In manufacture of a polarizer, an extending process may be performed at any stage. Specifically, it may be performed simultaneously with swelling, dyeing, and crosslinking, or may be performed either before or after each of these steps. In addition, extending|stretching may be performed in multiple stages. The cumulative stretch ratio of the polyvinyl alcohol-based film is usually 5 times or more, preferably about 5 to 7 times.

In the present invention, the polarizer preferably contains a metal component capable of becoming a divalent metal cation in water, and more preferably contains magnesium, calcium, copper or zinc, and particularly preferably contains zinc. . When a polarizer contains zinc, there exists a tendency for the fall of the transmittance|permeability and color deterioration of the polarizing film after a heating test to be suppressed. When a polarizer contains zinc, 0.002 to 2 weight% is preferable and, as for content of zinc in a polarizer, 0.01 to 1 weight% is more preferable.

In this invention, it is preferable that a polarizer contains sulfate ion. When the polarizer contains sulfate ions, there is a tendency for a decrease in the transmittance of the polarizing film after the heating test to be suppressed. When the polarizer contains sulfate ions, the content of sulfate ions in the polarizer is preferably from 0.02 to 0.45% by weight, more preferably from 0.05 to 0.35% by weight, still more preferably from 0.1 to 0.25% by weight. In addition, content of the sulfate ion in a polarizer is computed from sulfur atom content.

In order to contain zinc in a polarizer, it is preferable that zinc impregnation treatment is performed in the manufacturing process of a polarizer. Moreover, in order to contain sulfate ion in a polarizer, it is preferable that a sulfate ion treatment is performed in the manufacturing process of a polarizer.

Zinc impregnation treatment is performed by immersing the polyvinyl alcohol-based film in a zinc salt solution, for example. As the zinc salt, zinc halides such as zinc chloride and zinc iodide, and inorganic salt compounds of aqueous solutions such as zinc sulfate and zinc acetate are suitable. In addition, various zinc complex compounds may be used for the zinc impregnation treatment. In addition, as for the zinc salt solution, it is preferable to use an aqueous solution containing potassium ions and iodine ions by potassium iodide or the like because zinc ions are easily impregnated. The potassium iodide concentration in the zinc salt solution is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight.

Sulfate ion treatment is performed, for example, by immersing the polyvinyl alcohol-based film in an aqueous solution containing a metal sulfate salt. The metal sulfate is preferably one that is easily separated into sulfate ions and metal ions in the treatment liquid and is easily introduced in the form of ions into the polyvinyl alcohol-based film. For example, as a kind of metal which forms a sulfate metal salt, Alkali metals, such as sodium and potassium; alkaline earth metals such as magnesium and calcium; and transition metals such as cobalt, nickel, zinc, chromium, aluminum, copper, manganese, and iron.

In manufacture of a polarizer, the zinc impregnation treatment and sulfate ion treatment may be performed at any stage. That is, the zinc impregnation treatment and the sulfate ion treatment may be performed before the dyeing step or after the dyeing step. Zinc impregnation treatment and sulfate ion treatment may be performed simultaneously. In the present invention, it is preferable that zinc impregnation treatment and sulfate ion treatment are performed simultaneously by using zinc sulfate as the zinc salt and the metal sulfate salt, and immersing the polyvinyl alcohol-based film in a treatment bath containing zinc sulfate. . In addition, the zinc salt or the metal sulfate salt may coexist in the dyeing solution, and the zinc impregnation treatment and/or the sulfate ion treatment may be performed simultaneously with the dyeing step. Zinc impregnation treatment and sulfate ion treatment may be performed simultaneously with stretching.

In the zinc impregnation treatment and the sulfate ion treatment, conditions such as the concentration of the zinc salt solution and the metal sulfate solution, the immersion temperature of the polyvinyl alcohol-based film in the treatment bath, and the immersion time are adjusted so that the zinc content and sulfate ions in the polarizer are adjusted. content is adjusted. In the zinc impregnation treatment and the sulfate ion treatment, the temperature of the zinc salt solution and the metal sulfate solution is usually about 15 to 85°C, preferably 25 to 70°C. The immersion time is usually in the range of about 1 to 120 seconds, preferably in the range of 3 to 90 seconds. The concentration of the zinc salt solution and the metal sulfate solution varies depending on the type of zinc salt or metal sulfate salt, but is usually about 0.5 to 20% by weight, preferably 1 to 10% by weight, more preferably 2 to 7% by weight. am. By making zinc salt concentration and metal sulfate concentration into the said range, zinc content and sulfate ion content in a polarizer can be made into the said preferable range.

The polyvinyl alcohol-based film (stretched film) subjected to each of the above treatments is subjected to a water washing step and a drying step according to a conventional method.

The water washing step is usually performed by immersing the polyvinyl alcohol-based film in a water washing bath. The water washing bath may be pure water or an aqueous solution of iodide (eg, potassium iodide, sodium iodide, etc.). The concentration of the iodide aqueous solution is preferably 0.1 to 10% by weight. Auxiliary agents, such as zinc sulfate and zinc chloride, may be added to the iodide aqueous solution.

The water washing temperature is usually in the range of 5 to 50°C, preferably 10 to 45°C, and more preferably 15 to 40°C. The immersion time is usually about 10 to 300 seconds, preferably 20 to 240 seconds. The water washing step may be performed only once, or may be performed a plurality of times as needed. When the water washing step is performed a plurality of times, the type and concentration of additives contained in the water washing bath used for each treatment are appropriately adjusted.

The drying step of the polyvinyl alcohol-based film is performed by any suitable method (for example, natural drying, blowing drying, heat drying). It is preferable that the thickness of the polarizer after a drying process is 3-20 micrometers.

In this invention, you may perform the surface modification process of the obtained light polarizer. Examples of the surface modification treatment include treatments such as corona treatment, plasma treatment, and ytro treatment, and corona treatment is particularly preferred. By corona treatment, reactive functional groups, such as a carbonyl group and an amino group, are produced|generated on the surface of a polarizer, and adhesiveness with a durability improving layer improves. In addition, foreign matter on the surface is removed by the ashing effect or surface irregularities are reduced, so that a polarizing film having excellent appearance properties can be manufactured.

In the present invention, the polarizing film includes a polarizer and an adhesive layer adjacent to the polarizer or optical films other than the polarizer. In the polarizing film 10 shown in FIG. 1, the adhesive bond layer adjacent to optical films (retardation film) 4 other than the polarizer 1 is provided. Moreover, in the polarizing film 10 shown in FIG. 2, the adhesive bond layer 5 adjacent to the polarizer 1 is provided. Below, the adhesive layer is demonstrated.

<Adhesive layer>

The adhesive layer is formed of a cured product layer of an adhesive composition, and is particularly preferably formed of a cured product layer of an active energy ray curable adhesive composition such as electron beam curable, ultraviolet curable, or visible ray curable. The thickness of the adhesive layer after drying is preferably 0.01 μm to 5 μm, and more preferably 0.01 μm to 3 μm, from the viewpoint of improving the appearance characteristics of the polarizing film. The active energy ray-curable adhesive composition can be classified into a radical polymerization-curable adhesive composition and a cationic polymerization adhesive composition. In the present invention, active energy rays in the wavelength range of 10 nm to less than 380 nm are expressed as ultraviolet rays, and active energy rays in the wavelength range of 380 nm to 800 nm are expressed as visible rays.

As a monomer component constituting the radical polymerization-curable adhesive composition, a radical polymerizable compound is exemplified. Examples of the radically polymerizable compound include compounds having radically polymerizable functional groups of carbon-carbon double bonds such as a (meth)acryloyl group and a vinyl group. As these monomer components, either a monofunctional radically polymerizable compound or a polyfunctional radically polymerizable compound having two or more polymerizable functional groups can be used. Moreover, these radically polymerizable compounds can be used individually by 1 type or in combination of 2 or more types. As these radically polymerizable compounds, compounds having a (meth)acryloyl group are preferable, for example. In addition, in this invention, (meth)acryloyl means an acryloyl group and/or a methacryloyl group, and "(meth)" has the same meaning below.

As a monofunctional radically polymerizable compound, the (meth)acrylamide derivative which has a (meth)acrylamide group is mentioned, for example. A (meth)acrylamide derivative is preferable in terms of high polymerization rate and excellent productivity in securing adhesiveness with a polarizer or various transparent protective films. Specific examples of the (meth)acrylamide derivative include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N- N-alkyl group-containing (meth)acrylamide derivatives such as isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-hexyl (meth)acrylamide; N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as N-methylol (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N-methylol-N-propane (meth)acrylamide; N-aminoalkyl group-containing (meth)acrylamide derivatives such as aminomethyl (meth)acrylamide and aminoethyl (meth)acrylamide; N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth)acrylamide derivatives such as mercaptomethyl (meth)acrylamide and mercaptoethyl (meth)acrylamide; etc. can be mentioned. Moreover, as a heterocyclic containing (meth)acrylamide derivative in which the nitrogen atom of a (meth)acrylamide group forms a heterocyclic ring, for example, N-acryloylmorpholine, N-acryloylpiperidine, N -Methacryloylpiperidine, N-acryloylpyrrolidine, etc. are mentioned.

Among the above-mentioned (meth)acrylamide derivatives, N-hydroxyalkyl group-containing (meth)acrylamide derivatives are preferred from the viewpoint of adhesive properties with polarizers and various transparent protective films, and examples of monofunctional radically polymerizable compounds include: For example, various (meth)acrylic acid derivatives having a (meth)acryloyloxy group are exemplified. Specifically, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2-methyl-2-nitropropyl (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 (meth)acrylic acid (C 1 - 20) alkyl esters such as lactate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and n-octadecyl (meth)acrylate can be heard

Moreover, as said (meth)acrylic acid derivative, For example, cycloalkyl (meth)acrylates, such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl(meth)acrylate, 2-norbornylmethyl(meth)acrylate, 5-norbornen-2-yl-methyl(meth)acrylate, 3-methyl-2-norbornylmethyl polycyclic (meth)acrylates such as (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol ( (meth)acrylates containing an alkoxy group or phenoxy group, such as meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxypolyethylene glycol (meth)acrylate; etc. can be mentioned.

Moreover, as said (meth)acrylic acid derivative, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl ( meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12 -Hydroxyalkyl (meth)acrylates such as hydroxylauryl (meth)acrylate, [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, 2- hydroxyl group-containing (meth)acrylates such as hydroxy-3-phenoxypropyl (meth)acrylate; epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth) halogen-containing (meth)acrylates such as acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate; Alkylaminoalkyl (meth)acrylates, such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth)acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth)acrylate ) oxetane group-containing (meth)acrylates such as acrylate and 3-hexyl-oxetanylmethyl (meth)acrylate; Heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate, neopentylglycol hydroxypivalate (meth)acrylic acid adducts, p-phenylphenol ( Meth) acrylate etc. are mentioned.

Moreover, as a monofunctional radically polymerizable compound, carboxyl group-containing monomers, such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid, are mentioned.

Moreover, as a monofunctional radically polymerizable compound, For example, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, methylvinylpyrrolidone, etc. Lactam system vinyl monomers; and nitrogen-containing heterocyclic vinyl monomers such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

Moreover, as a monofunctional radically polymerizable compound, the radically polymerizable compound which has an active methylene group can be used. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the terminal or in a molecule and also having an active methylene group. As an active methylene group, an acetoacetyl group, an alkoxymalonyl group, or a cyanoacetyl group etc. are mentioned, for example. It is preferable that the said active methylene group is an acetoacetyl group. Specific examples of the radically polymerizable compound having an active methylene group include, for example, 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, 2-acetoacetoxy-1-methyl acetoacetoxyalkyl (meth)acrylates such as ethyl (meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxy Butyl) acrylamide, N-(4-acetoacetoxymethylbenzyl) acrylamide, N-(2-acetoacetylaminoethyl) acrylamide, etc. are mentioned. The radically polymerizable compound having an active methylene group is preferably an acetoacetoxyalkyl (meth)acrylate.

Moreover, as a polyfunctional radically polymerizable compound which has two or more polymerizable functional groups, for example, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di( meth)acrylate, 1,9-nonanedioldi(meth)acrylate, 1,10-decanedioldiacrylate, 2-ethyl-2-butylpropanedioldi(meth)acrylate, bisphenol A di(meth) Acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neopentylglycoldi(meth) Acrylate, tricyclodecane dimethanol di(meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaeryth Litol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO modified diglycerin tetra(meth)acrylate esterified products of (meth)acrylic acid and polyhydric alcohol, such as the like, and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Specific examples include Aronix M-220 (manufactured by Toa Chemical Co., Ltd.), light acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), light acrylate DGE-4A (manufactured by Kyoeisha Chemical Co.), and light acrylate DCP. -A (made by Kyoeisha Chemical Co., Ltd.), SR-531 (made by Sartomer), CD-536 (made by Sartomer), etc. are mentioned. Moreover, as needed, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate-based monomers, etc. are mentioned.

In the present invention, the polarizing film is provided with a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, and the adhesive layer is formed of a cured product layer of an adhesive composition, and is obtained by curing the adhesive composition. When the cargo is immersed in pure water at 23 ° C for 24 hours,

Formula: {(M2−M1)/M1}×100 (%),

However, M1: weight of cured material before immersion, M2: weight of cured material after immersion,

It is preferable that the bulk water absorption represented by is less than 10% by weight. According to this configuration, even when a specific metal component contained in the polarizer is mixed in the adhesive layer from the end portion, the binding between the ionized oxalic acid and the metal component and the movement of oxalate from the polarizing film end portion to the inside are suppressed. As a result, even after the humidification durability test, the appearance characteristics of the polarizing film are particularly improved. The bulk water absorption is more preferably less than 8% by weight, and particularly preferably less than 6% by weight.

In the present invention, the polarizing film includes a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, and based on the measurement of the element ratio of the adhesive layer, (number of carbon atoms)/(number of oxygen atoms) + the number of nitrogen atoms) is preferably 2.5 or more. In general, it is considered that the binding of ionized oxalic acid with metal components and, consequently, the movement of oxalate occurs through water. Here, in the adhesive layer, when (the number of carbon atoms)/(the number of oxygen atoms + the number of nitrogen atoms) based on the measurement of the ratio of elements in the adhesive layer is 2.5 or more, the penetration of water into the adhesive layer from the end portion is suppressed. Thus, in the end portion of the adhesive layer, in particular, the bonding between the ionized oxalic acid and the metal component and the movement of the oxalate from the end portion of the polarizing film to the inside can be suppressed. As a result, the appearance characteristics of the polarizing film are remarkably improved even after the humidification durability test. A method for measuring the element ratio of the adhesive layer will be described later.

In the present invention, the polarizing film includes a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer, and the adhesive layer is formed of a cured product layer of an adhesive composition, and the adhesive composition contains It is preferable that logPow representing the octanol/water partition coefficient by the weighted average of the mole fractions of the monomer components is 1.6 or more. In general, it is considered that the binding of ionized oxalic acid with metal components and, consequently, the movement of oxalate occurs through water. Here, when logPow representing the octanol/water partition coefficient based on the weighted average of the mole fractions of the monomer components contained in the adhesive composition is 1.6 or more, intrusion of water from the end into the adhesive layer is suppressed, and particularly in the end portion of the adhesive layer. In this case, the binding between the ionized oxalic acid and the metal component and the movement of the oxalate from the edge of the polarizing film to the inside can be suppressed. As a result, the appearance characteristics of the polarizing film are remarkably improved even after the humidification durability test.

The octanol/water partition coefficient (logPow) is an index indicating the lipophilicity of a substance, and means the logarithm of the octanol/water partition coefficient. A high logPow means that it is lipophilic, that is, it means that the absorption rate is low. The logPow value can also be measured (flask shaking method described in JIS-Z-7260), but can also be calculated by calculation. In this specification, the logPow value calculated by Chem Draw Ultra by Cambridge Soft Co., Ltd. is used.

It shows below about the logPow of a main radically polymerizable compound. Hydroxyethyl acrylamide (trade name "HEAA", manufactured by Kojin Co., LogPow: -0.56), diethyl acrylamide (trade name "DEAA", manufactured by KJ Chemicals, LogPow: 1.69), unsaturated fatty acid hydroxyalkyl ester formula ε- Caprolactone (trade name "Fraxel FA1DDM", manufactured by Daicel Corporation, LogPow; 1.06), N-vinylformamide (trade name "Beamset 770", manufactured by Arakawa Chemical Co., LogPow; -0.25) acryloylmorpholine (trade name "ACMO" , Kojin Co., Ltd. LogPow; -0.20), γ-butyrolactone acrylate (trade name "GBLA", Osaka Organic Chemical Industry Co., Ltd., LogPow: 0.19), acrylic acid dimer (trade name "β-CEA", Daicel Co., Ltd., LogPow ; 0.2), N-vinylpyrrolidone (trade name "NVP", manufactured by Nippon Catalyst, LogPow; 0.24), acetoacetoxyethyl methacrylate (trade name "AAEM", manufactured by Nippon Synthetic Chemical Co., LogPow; 0.27), 2 -Hydroxyethyl acrylate (trade name "HEA", manufactured by Osaka Organic Chemical Industries, Ltd., LogPow; 0.28), glycidyl methacrylate (trade name "Light Ester G", manufactured by Kyoeisha Chemical, LogPow; 0.57), dimethyl acryl Amide (trade name "DMAA", manufactured by Kojin Co., LogPow; 0.58), tetrahydrofurfuryl alcohol acrylic acid multimer ester (trade name "BISCOTT #150D", manufactured by Osaka Organic Chemical Co., Ltd., LogPow; 0.60), 4-hydroxybutyl Acrylate (trade name "4-HBA", manufactured by Osaka Organic Chemical Industries, Ltd., LogPow; 0.68), acrylic acid (trade name "Acrylic Acid", manufactured by Mitsubishi Chemical Corporation, LogPow; 0.69), triethylene glycol diacrylate (trade name "Light Acrylate 3EG" -A", Kyoeisha Chemical Co., LogPow; 0.72), PEG400# diacrylate (trade name "Light Acrylate 9EG-A", Kyoeisha Chemical Co., LogPow: -0.1) polypro Pylene glycol diacrylate (trade name "Aronix M-220", manufactured by Toa Chemical Co., Ltd., LogPow; 1.68), dicyclopentenyl acrylate (trade name "Pancryl FA-511AS", manufactured by Hitachi Chemical Co., Ltd., LogPow; 2.26), butyl acrylate (trade name ""butyl acrylate", manufactured by Mitsubishi Chemical Corporation, LogPow; 2.35), 1,6 -Hexanediol diacrylate (trade name "Light Acrylate 1.6HX-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 2.43), dicyclopentanyl acrylate (trade name "Pancryl FA-513AS", manufactured by Hitachi Chemical Co., Ltd., LogPow ; 2.58), dimethylol-tricyclodecane diacrylate (trade name "light acrylate DCP-A", Kyoeisha Chemical Co., Ltd., LogPow; 3.05), isobornyl acrylate (trade name "light acrylate IB-XA" , Kyoeisha Chemical Co., LogPow; 3.27), hydroxypivalic acid neopentyl glycol acrylic acid adduct (trade name "Light Acrylate HPP-A", Kyoeisha Chemical Co., LogPow; 3.35), 1,9-nonanedi Old diacrylate (trade name "Light Acrylate 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 3.68), o-phenylphenol EO modified acrylate (trade name "Pancryl FA-301A", manufactured by Hitachi Kasei Co., Ltd., LogPow; 3.98), 2-Ethylhexyloxetane (trade name "Aronoxetane OXT-212", manufactured by Toa Chemical Co., Ltd., LogPow; 4.24), bisphenol-A-diglycidyl ether (trade name "JER828", manufactured by Mitsubishi Chemical Corporation, LogPow; 4.76), bisphenol A EO 6 mol modified diacrylate (trade name "FA-326A", manufactured by Hitachi Chemical Co., Ltd., LogPow; 4.84), bisphenol A EO 4 mol modified diacrylate (trade name "FA-324A", Hitachi Chemical Co., Ltd. LogPow; 5.15), bisphenol APO 2 mol modified diacrylate (trade name "FA-P320A", Hitachi Kasei Co., LogPow; 6.10), bisphenol APO 3 mol modified diacrylate (trade name "FA- P323A", manufactured by Hitachi Chemical Co., Ltd., LogPow ; 6.26), bisphenol A PO 4 mole modified diacrylate (trade name "FA-P324A", manufactured by Hitachi Chemical Co., Ltd., LogPow; 6.43), lauryl acrylate (trade name "Light Acrylate LA", manufactured by Kyoeisha Chemical Co., Ltd., LogPow 6), isostearyl acrylate (trade name "ISTA", manufactured by Osaka Organic Chemical Industry; LogPow; 7.46), and the like.

The adhesive layer is formed of a cured product layer of the adhesive composition, and logPow representing the octanol/water partition coefficient by the weighted average of the mole fractions of the monomer components contained in the adhesive composition is 1.6 or more, so that the monomer components When the total amount is 100 parts by weight, it is preferable to contain 25 parts by weight or more of the monomer component having an alkyl group having 8 or more carbon atoms. As a monomer component having an alkyl group having 8 or more carbon atoms, the aforementioned dicyclopentanyl acrylate (trade name "Pancryl FA-513AS", manufactured by Hitachi Chemical Co., Ltd., LogPow; 2.58), lauryl acrylate (trade name "light acrylate L-A") ”, manufactured by Kyoeisha Chemical Co., Ltd., LogPow; 6), isostearyl acrylate (trade name: “ISTA”, manufactured by Osaka Organic Chemical Industries, Ltd.; LogPow; 7.46), and the like.

The adhesive layer is formed of a cured material layer of an adhesive composition, and has a hydroxyl group so that logPow representing an octanol/water partition coefficient based on a weighted average of mole fractions of monomer components contained in the adhesive composition is 1.6 or more. It is preferable to make content of a monomer component into 40 parts by weight or less. Moreover, as a monomer component which has a hydroxyl group, the monomer component which has a hydroxyl group is mentioned among the said monomer components.

Moreover, in this invention, a polarizing film is equipped with a polarizer and the adhesive bond layer adjacent to a polarizer or optical films other than a polarizer, and the adhesive bond layer is formed of the hardened|cured material layer of adhesive composition, and the adhesive composition is a monomer When the total amount of components is 100 parts by weight, it is preferable to contain 25 parts by weight or more of the monomer component having two or more polymerizable functional groups, and more preferably 30 parts by weight or more. Such an adhesive layer, even if oxalate is generated, inhibits crystal growth of the oxalate because of the high hardness of the adhesive layer. As a result, the occurrence of foreign matter originating from oxalate is suppressed, and the appearance characteristics of the polarizing film are remarkably improved.

Examples of the monomer component having two or more polymerizable functional groups include polyfunctional radical polymerizable compounds having two or more polymerizable functional groups. In particular, when the adhesive composition contains 25 parts by weight or more of the monomer component having two or more polymerizable functional groups based on 100 parts by weight of the total amount of the monomer components, the content of the monomer component having a hydroxyl group is 40 parts by weight or less It is desirable to do

In the present invention, an acrylic oligomer obtained by polymerizing a (meth)acrylic monomer may be contained in the adhesive composition as a raw material of the adhesive layer included in the polarizing film, in addition to the radically polymerizable compound. By containing the acrylic oligomer in the adhesive composition, curing shrinkage at the time of irradiating and curing the composition with active energy rays can be reduced, and the interface stress between the adhesive layer and an adherend such as a polarizer and a transparent protective film can be reduced. . As a result, a decrease in the adhesiveness between the adhesive layer and the adherend can be suppressed.

Since the active energy ray-curable adhesive is preferably low viscosity when workability and uniformity at the time of application are considered, the acrylic oligomer obtained by polymerizing (meth)acrylic monomers is also preferably low viscosity. The acrylic oligomer having a low viscosity and capable of preventing curing shrinkage of the adhesive layer has a weight average molecular weight (Mw) of preferably 15000 or less, more preferably 10000 or less, and particularly preferably 5000 or less. On the other hand, in order to sufficiently suppress cure shrinkage of the cured material layer (adhesive layer), the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and particularly preferably 1500 or more. Specific examples of the (meth)acrylic monomer constituting the acrylic oligomer include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. , 2-methyl-2-nitropropyl (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, etc. meth)acrylic acid (C 1 - 20) alkyl esters, also for example, cycloalkyl (meth)acrylates (eg, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.), aralkyl (meth)acrylates (e.g., benzyl (meth)acrylate, etc.), polycyclic (meth)acrylates (e.g., 2-isobornyl(meth)acrylate, 2-norbornylmethyl(meth)acrylate, )Acrylates, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, etc.), hydroxyl group-containing (meth)acrylic acid esters ( For example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)methacrylate, etc.), containing an alkoxy group or a phenoxy group (meth)acrylic acid esters (2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate) acrylate, ethylcarbitol (meth)acrylate, phenoxyethyl (meth)acrylate, etc.), epoxy group-containing (meth)acrylic acid esters (eg, glycidyl (meth)acrylate, etc.), halogen-containing ( meth)acrylic acid esters (e.g., 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-t Lifluoroethylethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate rate, etc.), alkylaminoalkyl (meth)acrylates (for example, dimethylaminoethyl (meth)acrylate, etc.), etc. are mentioned. These (meth)acrylates can be used alone or in combination of two or more. As a specific example of an acryl-type oligomer (E), "ARUFON" by a Toa synthetic company, "Act flow" by a Soken chemical company, "JONCRYL" by a BASF Japan company, etc. are mentioned.

It is preferable that the blending amount of the acrylic oligomer is usually 15 parts by weight or less with respect to 100 parts by weight of the total amount of the monomer components in the adhesive composition. When the content of the acrylic oligomer in the adhesive composition is too large, the reaction rate when the composition is irradiated with active energy rays is drastically reduced, resulting in poor curing in some cases. On the other hand, in order to sufficiently suppress cure shrinkage of the adhesive layer, it is preferable to contain 3 parts by weight or more of the acrylic oligomer in the composition.

The photopolymerization initiator in the case of using a radically polymerizable compound is appropriately selected according to the active energy ray. In the case of curing with ultraviolet light or visible light, a photopolymerization initiator capable of cleavage by ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone-based compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α - Aromatic ketone compounds such as hydroxycyclohexylphenyl ketone; Methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane acetophenone-based compounds such as -1; benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, and anisoin methyl ether; Aromatic ketal type compounds, such as benzyl dimethyl ketal; Aromatic sulfonyl chloride type compounds, such as 2-naphthalene sulfonyl chloride; photoactive oxime-based compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; Thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone thioxanthone-based compounds such as xanthones, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; halogenated ketones; Acylphosphine oxide; Acyl phosphonate etc. are mentioned.

The compounding quantity of the said photoinitiator is 20 weight% or less when the total amount of an active energy ray-curable adhesive composition is 100 weight%. The blending amount of the photopolymerization initiator is preferably 0.01 to 20% by weight, more preferably 0.05 to 10% by weight, more preferably 0.1 to 5% by weight.

Moreover, when using the curable adhesive for polarizing films of this invention in the visible light curing type containing a radically polymerizable compound as a curable component, it is preferable to use the photoinitiator which is highly sensitive especially with respect to the light of 380 nm or more. A photopolymerization initiator highly sensitive to light of 380 nm or more will be described later.

Compounds represented by the following general formula (1) as said photopolymerization initiator;

[Formula 1]

(In the formula, R ¹ and R ² represent -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different) may be used alone, or the general formula (1 ) and a photopolymerization initiator that is highly sensitive to light of 380 nm or more described later is preferably used in combination. When the compound represented by the general formula (1) is used, the adhesiveness is excellent compared to the case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), diethylthioxanthone in which R ¹ and R ² are -CH ₂ CH ₃ is particularly preferred. The composition ratio of the compound represented by the general formula (1) in the adhesive composition is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 4 parts by weight, and 0.9 to 3 parts by weight based on 100 parts by weight of the total amount of the curable component. Denial is more preferable.

Moreover, it is preferable to add a polymerization initiation adjuvant as needed. Examples of polymerization initiation aids include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and 4-dimethylaminobenzoic acid. Soamyl etc. are mentioned, Ethyl 4-dimethylamino benzoate is especially preferable. When a polymerization initiation aid is used, the added amount is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component.

Moreover, a well-known photoinitiator can be used together as needed. Since the transparent protective film having UV absorption does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator highly sensitive to light of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-buta Non-1,2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2,4,6-trimethylbenzoyl -Diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro rho-3-(1H-pyrrol-1-yl)-phenyl)titanium; and the like.

In particular, as the photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (1), a compound further represented by the following general formula (2);

[Formula 2]

(In the formula, R ³ , R ⁴ and R ⁵ represent -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different) It is preferable to use As the compound represented by the general formula (2), 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: IRGACURE907 manufacturer: BASF), which is also a commercial product, can be preferably used. can In addition, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: IRGACURE369 maker: BASF), 2-(dimethylamino)-2-[(4-methylphenyl) ) Methyl] -1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferred because of its high sensitivity.

In this invention, it is preferable to use the photoinitiator containing a hydroxyl group also in the said photoinitiator. When the active energy ray-curable adhesive composition contains a photopolymerization initiator containing a hydroxyl group as the polymerization initiator, the solubility of the component A on the polarizer side in the high-concentration adhesive layer increases, and the curability of the adhesive layer increases. Examples of the photopolymerization initiator having a hydroxyl group include 2-methyl-2-hydroxypropiophenone (trade name "DAROCUR1173", manufactured by BASF), 1-hydroxycyclohexylphenyl ketone (trade name "IRGACURE184", BASF), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (trade name "IRGACURE2959", BASF), 2 -Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (trade name "IRGACURE127", manufactured by BASF) etc. can be mentioned. In particular, 1-hydroxycyclohexylphenyl ketone is more preferable because it has particularly excellent solubility in an adhesive layer having a high concentration of component A.

As the cationically polymerizable compound used in the cationic polymerizable adhesive composition, a monofunctional cationically polymerizable compound having one cationically polymerizable functional group in a molecule and a monofunctional cationically polymerizable compound having two or more cationically polymerizable functional groups in a molecule It is classified as a functional cationic polymerizable compound. Since the liquid viscosity of a monofunctional cationically polymerizable compound is comparatively low, the liquid viscosity of a resin composition can be reduced by containing it in a resin composition. In addition, monofunctional cationically polymerizable compounds often have a functional group that exhibits various functions, and by incorporating them into a cationically polymerizable adhesive composition, the cationically polymerizable adhesive composition and/or the cured product of the cationically polymerizable adhesive composition Various functions can be expressed in Since a polyfunctional cationically polymerizable compound can crosslink three-dimensionally the hardened|cured material of a cationically polymerizable adhesive composition, it is preferable to contain it in a cationically polymerizable adhesive composition. The ratio of the monofunctional cationically polymerizable compound and the multifunctional cationically polymerizable compound is mixed in the range of 10 parts by weight to 1000 parts by weight of the polyfunctional cationically polymerizable compound with respect to 100 parts by weight of the monofunctional cationically polymerizable compound. It is desirable to do An epoxy group, an oxetanyl group, and a vinyl ether group are mentioned as a cationically polymerizable functional group. Examples of the compound having an epoxy group include aliphatic epoxy compounds, alicyclic epoxy compounds, and aromatic epoxy compounds. As the cationically polymerizable adhesive composition of the present invention, an alicyclic epoxy compound is selected from the viewpoint of excellent curability and adhesiveness. It is particularly preferable to contain. As the alicyclic epoxy compound, caprolactone modification of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate Water, trimethyl caprolactone modified product, valerolactone modified product, etc. are mentioned, Specifically, Celoxide 2021, Celoxide 2021A, Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (above, die Cell Chemical Industry Co., Ltd.), Cyracure UVR-6105, Cyracure UVR-6107, Cyracure 30, R-6110 (above, Dow Chemical Japan Co., Ltd. product), etc. are mentioned. The compound having an oxetanyl group is effective in improving the curability of the cationic polymerizable adhesive composition or reducing the liquid viscosity of the composition, and therefore it is preferable to contain the compound. As the compound having an oxetanyl group, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]benzene, 3-ethyl-3- (phenoxymethyl)oxetane, di[(3-ethyl-3-oxetanyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, phenol novolak oxetane, etc. Aaron oxetane OXT-101, Aaron oxetane OXT-121, Aaron oxetane OXT-211, Aaron oxetane OXT-221, Aaron oxetane OXT-212 (above, manufactured by Toa Synthetic Industries Co., Ltd.) and the like are commercially available. A compound having a vinyl ether group is preferably incorporated because it has an effect of improving the curability of the cationic polymerizable adhesive composition or lowering the liquid viscosity of the composition. As the compound having a vinyl ether group, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexane dimethanol di Vinyl ether, cyclohexanedimethanol monovinyl ether, tricyclodecane vinyl ether, cyclohexyl vinyl ether, methoxyethyl vinyl ether, ethoxyethyl vinyl ether, pentaerythritol type tetravinyl ether, etc. are mentioned.

The cationic polymerizable adhesive composition contains, as a curable component, at least one compound selected from the above-described compound having an epoxy group, compound having an oxetanyl group, and compound having a vinyl ether group, all of which are cured by cationic polymerization. Since it is a thing, a photocationic polymerization initiator is mix|blended. This photocationic polymerization initiator generates a cation species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy group or an oxetanyl group. As a photocationic polymerization initiator, the photoacid generator mentioned later is used preferably. In addition, when using a cationic polymerizable adhesive composition with visible light curability, it is preferable to use a photocationic polymerization initiator that is highly sensitive to light of 380 nm or more, but a photocationic polymerization initiator is generally around 300 nm Or, since it is a compound that exhibits maximum absorption in a shorter wavelength range, by blending a photosensitizer that exhibits maximum absorption in a longer wavelength range, specifically, to light with a wavelength longer than 380 nm, By reacting, generation of a cation species or an acid from a photocationic polymerization initiator can be promoted. Examples of the photosensitizer include anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducing dyes. , You may mix and use two or more types. Anthracene compounds are particularly preferred because of their excellent photosensitizing effect, and specific examples thereof include Anthracure UVS-1331 and Anthracure UVS-1221 (manufactured by Kawasaki Kasei Co., Ltd.). It is preferable that they are 0.1 weight% - 5 weight%, and, as for content of a photosensitizer, it is more preferable that they are 0.5 weight% - 3 weight%.

<Optical Film>

In this invention, as an optical film with which a polarizing film is equipped, a transparent protective film and retardation film are mentioned, for example. In addition, you may perform a surface modification process not only to a polarizer but also to an optical film. Examples of the surface modification treatment include treatments such as corona treatment, plasma treatment, and ytro treatment, and corona treatment is particularly preferred.

As a material constituting the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, water barrier properties, isotropy and the like is used. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and (meth)acrylic resins. resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. One or more types of arbitrary appropriate additives may be contained in the transparent protective film. As an additive, a ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a coloring agent, etc. are mentioned, for example. 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, even more preferably 60 to 98% by weight, 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, there is a risk that the high transparency and the like originally possessed by the thermoplastic resin cannot be sufficiently expressed.

In addition, the material forming the transparent protective film is preferably a material having excellent transparency, mechanical strength, thermal stability, water barrier properties, isotropy, etc., more preferably having a moisture permeability of 150 g/m ² /24h or less, and 140 g/m 2 /24h or less. It is particularly preferably equal to or less than m ² /24h, and more preferably equal to or less than 120 g/m ² /24h.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer can be formed on the surface of the transparent protective film to which the polarizer is not adhered. In addition, the functional layer such as the hard coat layer, antireflection layer, antisticking layer, diffusion layer or antiglare layer can be formed on the transparent protective film itself or separately from the transparent protective film. may be

The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm, preferably 1 to 300 μm, and more preferably 5 to 200 μm, from the viewpoint of strength, workability such as handling and thin layer properties. desirable. Furthermore, 10-200 micrometers are preferable and 20-80 micrometers are preferable.

As the transparent protective film, a retardation film having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more may be used. The front retardation is usually controlled in the range of 40 to 200 nm, and the thickness direction retardation is usually controlled in the range of 80 to 300 nm. Since the retardation film functions also as a transparent protective film when using retardation film as a transparent protective film, thickness reduction can be aimed at.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymeric material, an alignment film of liquid crystal polymer, and a film supporting an alignment layer of liquid crystal polymer. The thickness of the retardation film is also not particularly limited, but is generally about 20 to 150 μm.

As the retardation film, the following formulas (1) to (3):

0.70 < Re[450]/Re[550] < 0.97 … (One)

1.5×10 ^-3 <Δn < 6×10 ^-3 . (2)

1.13 < NZ < 1.50 … (3)

(Wherein, Re[450] and Re[550] are in-plane retardation values of the retardation film measured with light having wavelengths of 450 nm and 550 nm at 23° C., respectively, and Δn is the direction of the slow axis of the retardation film , nx-ny in-plane birefringence when the refractive index in the fast axis direction is nx and ny, respectively, and NZ is the thickness-direction birefringence nx-nz and in-plane birefringence when nz is the refractive index in the thickness direction of the retardation film A ratio of nx-ny) may be used.

The polarizing film concerning this invention can be manufactured by the following manufacturing method, for example.

A method for producing a polarizing film comprising a polarizer and an adhesive layer adjacent to a first optical film other than the polarizer, comprising: a first bonding step of bonding the polarizer and the first optical film together through a water-based adhesive layer; The manufacturing method of the polarizing film provided with the 2nd adhering process of adhering the said 1st optical film and the 2nd optical film via the said adhesive bond layer. It is preferable that the polarizer contains a metal component capable of becoming a divalent metal cation in water, particularly zinc. Moreover, it is preferable that the said adhesive bond layer is what was formed of the hardened|cured material layer of an active energy ray-curable adhesive composition.

In addition, the polarizing film concerning this invention can be manufactured also by the following manufacturing method, for example.

A method for producing a polarizing film comprising a polarizer and an adhesive layer adjacent to the polarizer, comprising: a first bonding step of bonding the polarizer and a first optical film through the adhesive layer. It is preferable that the said polarizer contains a metal component which can become a divalent metal cation in water, especially zinc. Moreover, it is preferable that the said adhesive bond layer is what was formed of the hardened|cured material layer of an active energy ray-curable adhesive composition.

In the bonding process, various adhesive compositions are applied to adherends such as polarizers and optical films, adherends such as polarizers and optical films are bonded together, and the adhesive composition is cured. A method for coating the adhesive composition is appropriately selected depending on the viscosity of the adhesive composition and the target thickness, and examples thereof include a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, and a die coater. , a bar coater, a rod coater, and the like. Bonding of adherends such as a polarizer and an optical film can be performed by a roll laminator or the like.

The adhesive layer is formed of a cured product layer of an adhesive composition, and is particularly preferably formed of a cured product layer of an active energy ray curable adhesive composition such as electron beam curable, ultraviolet curable, or visible ray curable adhesive composition. In the bonding step, active energy rays (electron beam, ultraviolet rays, visible rays, etc.) are irradiated to cure the adhesive composition to form an adhesive layer. The irradiation direction of the active energy ray (electron beam, ultraviolet ray, visible ray, etc.) can be irradiated in any suitable direction. When the polarizing film according to the present invention is produced in a continuous line, the line speed varies depending on the curing time of the adhesive composition, but is preferably 5 to 100 m/min, more preferably 10 to 50 m/min, still more preferably Preferably, it is 20 to 30 m/min. When the line speed is too small, productivity is insufficient or damage to the transparent protective film is too great, so that a polarizing film that can withstand durability tests or the like cannot be manufactured. When the line speed is too high, curing of the curable resin composition becomes insufficient, and the desired adhesiveness may not be obtained.

The polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. Although the optical layer is not particularly limited, for example, a reflection plate, a transflective plate, a retardation plate (including a 1/2 or 1/4 wave plate), a visual compensation film, etc. for forming a liquid crystal display device, etc. One layer or two or more layers can be used for the optical layer that may be used. In particular, a reflective polarizing film or semi-transmissive polarizing film obtained by laminating a polarizing film of the present invention with a further reflective plate or a transflective reflective plate, an elliptically polarizing film or a circular polarizing film formed by further laminating a retardation plate on the polarizing film, and a polarizing film A polarizing film for a wide viewing angle formed by further laminating a visual compensation film, or a polarizing film formed by laminating a brightness enhancing film on the polarizing film is preferable.

An optical film in which the optical layer is laminated on a polarizing film can also be formed by sequentially separately laminated in the manufacturing process of a liquid crystal display device or the like, but an optical film obtained by laminating in advance has stability of quality, assembly work, etc. This is excellent and has the advantage of improving the manufacturing process of a liquid crystal display device or the like. Appropriate bonding means such as an adhesive layer can be used for lamination. When attaching the polarizing film or other optical films described above, their optical axes can be set to an appropriate arrangement angle depending on the target retardation characteristics and the like.

An adhesive layer for adhering to other members such as a liquid crystal cell may be formed on the above-described polarizing film or an optical film in which at least one polarizing film is laminated. The adhesive forming the adhesive layer is not particularly limited, but for example, an acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer may be appropriately selected and used as a base polymer. there is. In particular, those having excellent optical transparency, exhibiting adhesive properties such as appropriate wettability, cohesiveness, and adhesiveness, and excellent weather resistance and heat resistance, such as acrylic adhesives, can be preferably used.

The adhesive layer may be formed on one side or both sides of a polarizing film or an optical film as an overlapping layer of different composition or type. Moreover, when forming on both surfaces, it is also possible to set it as an adhesive layer of different composition, kind, thickness, etc. on the front and back of a polarizing film or an optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use, adhesive strength, and the like, and is generally 1 to 100 µm, preferably 5 to 30 µm, and particularly preferably 10 to 20 µm.

The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing contamination or the like until it is put into practical use. Thereby, contact with the adhesive layer can be prevented in the usual handling state. Excluding the above thickness conditions, for the separator, for example, a suitable thin material such as plastic film, rubber sheet, paper, cloth, nonwoven fabric, net, foam sheet, metal foil, or a laminate thereof may be selected from a silicone type or long chain as necessary. Appropriate ones according to the prior art, such as those coated with appropriate release agents such as alkyl-based, fluorine-based, and molybdenum sulfide, can be used.

The polarizing film or optical film of the present invention can be suitably used for formation of various devices such as a liquid crystal display device. Formation of the liquid crystal display device can be performed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling constituent parts such as a liquid crystal cell, a polarizing film or an optical film, and, if necessary, a lighting system, and attaching a drive circuit, but in the present invention, the present invention Except for using a polarizing film or an optical film, there is no particular limitation, and the conventional method can be followed. As for the liquid crystal cell, for example, any type such as TN type, STN type, or π type can be used.

A suitable liquid crystal display device, such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of a liquid crystal cell, and a backlight or reflector used in a lighting system, 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 forming a polarizing film or an optical film on both sides, they may be the same thing or a different thing. In addition, when forming a liquid crystal display device, for example, a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, and the like are formed in one or more layers at an appropriate location. can be placed

Example

Examples of the present invention are described below, but the embodiments of the present invention are not limited to these.

<Manufacture of polarizer>

A polyvinyl alcohol film having an average degree of polymerization of 2700 and a thickness of 45 μm was stretched and conveyed while dyeing between rolls having different circumferential speed ratios. First, the polyvinyl alcohol film is immersed in a water bath at 30 ° C. for 1 minute to swell, and then stretched 1.2 times in the transport direction (first stretching), followed by an aqueous solution of potassium iodide (0.03% by weight) and iodine (0.3% by weight) ( By immersing in 30 degreeC liquid temperature) for 1 minute, it extended|stretched 3 times (based on unstretched film) in the conveyance direction, dyeing|staining (2nd extending|stretching). Next, while immersing this stretched film in an aqueous solution (bath solution) of boric acid (4% by weight), potassium iodide (5% by weight), and zinc sulfate (3.5% by weight) for 30 seconds, it is 6 times (based on unstretched film) in the conveying direction. ) (third stretching). The polarizer 1 was obtained by drying this stretched film. The thickness of the polarizer 1 after drying was 18 micrometers. Moreover, the polarizer 2 was obtained according to the manufacturing method similar to the polarizer 1 except having used the 30-micrometer-thick polyvinyl alcohol film. The thickness of the polarizer 2 after drying was 12 micrometers.

<Active Energy Line>

As an active energy ray, visible light (gallium-encapsulated metal halide lamp) irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc. Bulb: V bulb Peak illuminance: 1600 mW/cm 2 , a cumulative irradiation amount of 1000/mJ/cm 2 (wavelength: 380 to 440 nm) was used. In addition, the illuminance of visible light was measured using the Sola-Check system manufactured by Solatell.

<Method for Measuring Element Ratio of Adhesive Layer>

The element ratio of the adhesive layer with which the polarizing film is equipped was measured by the following measuring method.

First, for any of the following polarizing film constitutions (1) and polarizing film constitution (2), an adhesive not constituting the polarizing film was applied to the surface of the second optical film and fixed to a metal support. Next, the adhesive layer to be measured was exposed by removing the adhesive and the first optical film or the second optical film using an ultra microtome. Next, an Ar-GCIB etching treatment was performed, and the exposed adhesive layer after the Ar-GCIB etching treatment was pressed and fixed to the sample stand with a Mo plate. Then, ESCA analysis was performed using a scanning X-ray photoelectron spectrometer (Quantum 2000 manufactured by ULVAC-PHI), wide scan measurement was performed, and qualitative analysis was performed. Further, a narrow scan measurement was performed for the carbon element, the oxygen element, and the nitrogen element, and the element ratio (atomic%) was calculated. From the obtained carbon element ratio (atomic%), oxygen element ratio (atomic%), and nitrogen element ratio (atomic%), (number of carbon atoms)/(number of oxygen atoms + number of nitrogen atoms) was calculated.

<Panel lighting test>

The on-dash monitor (TKH703) for vehicles manufactured by MAXWIN was disassembled and the liquid crystal panel was taken out. The polarizing film adhered to the viewing side of the liquid crystal panel was peeled off, and instead, the polarizing film related to each of the examples and comparative examples produced was cut out to the same size as the polarizing film peeled off from the liquid crystal panel, and the adhesive layer (thickness 20 micrometers) through which it bonded together so that the polarizing film and transmission axis which peeled off might become the same, and the liquid crystal panel was obtained.

In the above, the obtained liquid crystal panel was injected in an environment of 65°C and 95% for 1000 h, and was left to stand in a normal temperature and normal humidity environment for 24 h. Thereafter, the liquid crystal panel was mounted again on the disassembled monitor housing, a black image was displayed, and visual confirmation was performed. As a result, the case where only a black screen was displayed was marked as ○, and the case where a white haze-like display defect occurred on a part of the screen was marked as ×.

<Third optical film>

The 3rd optical film used by the following polarizing film structure (1) was manufactured by the following manufacturing method.

In an autoclave equipped with a stirrer, a cooling pipe, a nitrogen inlet pipe and a thermometer, 48 parts by weight of hydroxypropylmethylcellulose (manufactured by Shin-Etsu Chemical, trade name Metrose 60SH-50), 15601 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate 240 parts by weight of 3-ethyl-3-oxetanylmethyl acrylate and 45 parts by weight of t-butylperoxypivalate as a polymerization initiator were added, nitrogen bubbling was carried out for 1 hour, and then maintained at 49 ° C. for 24 hours while stirring, Radical suspension polymerization was carried out. It was then cooled to room temperature, and the resulting suspension containing polymer particles was centrifuged. After washing the obtained polymer twice with distilled water and twice with methanol, it was dried under reduced pressure.

The obtained fumaric acid ester-based resin (polymer having negative birefringence) was dissolved in a mixed solution of toluene/methyl ethyl ketone (50% by weight/50% by weight of toluene/methylethyl ketone) to obtain a 20% solution. Furthermore, dope was prepared by adding 5 parts by weight of tributyl trimellitate as a plasticizer to 100 parts by weight of fumaric acid ester-based resin.

As the support film, a biaxially stretched film (thickness: 75 µm, width: 1350 mm) of polyester (polyethylene-terephthalate/isophthalate copolymer) was used. The tensile modulus of elasticity (MD) at 140°C of the support was 800 MPa.

The winding object of the support film was set in the drawing-out part of the film forming apparatus, and heat treatment was performed with a heating furnace while unwinding the support film and conveying it to the downstream side. The temperature of the heat treatment was adjusted by changing the atmospheric temperature in the heating furnace. The heating time was adjusted by changing the transport speed of the support. On the support after heat treatment, the dope prepared in Synthesis Example A was applied so that the film thickness after drying was 6.3 μm, and dried at 140°C. The coated film after drying was rolled up as a laminate together with the support.

Free end uniaxial stretching was performed within a drawing furnace at a temperature of 140°C, while setting the said layered product in the feeding part of the stretching apparatus, feeding out the layered product and conveying it to the downstream side. The support was peeled off from the laminate after stretching to obtain a phase difference film having a thickness of 6 µm. The draw ratio was adjusted so that the in-plane retardation of the retardation film after peeling the support body might be set to 35 nm.

Example 1

As the adhesive, an aqueous solution containing an acetoacetyl group-containing polyvinyl alcohol resin (average degree of polymerization: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) and methylolmelamine at a weight ratio of 3:1 was used. Using this adhesive, a second optical film (triacetyl cellulose film with a hard coat layer (manufactured by Fujifilm Corporation, trade name "TG40UL) is applied to one surface (visible side surface) of the polarizer 1 under a temperature condition of 30 ° C. ", film thickness 40 μm)), and a first optical film (cycloolefin film with phase difference (manufactured by Nippon Zeon Corporation, trade name "ZT12", film thickness 17 μm)) on the other surface (image display cell side surface) of polarizer 1 After pasting together with a roll bonding machine, it was made to heat-dry in an oven then, and the laminated|multilayer film which laminated|stacked the optical film on both surfaces of a polarizer was manufactured.

Next, an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roll number: 1000 pieces/inch, rotation speed 140%/line speed) was applied to the cycloolefin film side containing the phase difference of the laminated film obtained above. Using, the adhesive composition adjusted to the compounding quantity of Table 1 was coated so that it might become 1 micrometer in thickness, and it bonded to the said 3rd optical film (film thickness of 6 micrometers) with a roll machine. Then, from the side of the third optical film, the visible light was irradiated with an active energy ray irradiation device to cure the adhesive composition, and then it was dried with hot air at 70 ° C. for 3 minutes to obtain a polarizing film (a polarizing film having this configuration referred to as "Polarizing Film Structure (1)"). The thickness of the adhesive layer after drying was 1 µm. The bonding line speed was 25 m/min.

A sample for evaluation of the humidification durability test in which the polarizing film according to manufactured Example 1 was bonded to one side of an alkali-free glass having a thickness of 0.7 mm through an adhesive layer (thickness of 20 μm) was prepared. A humidification durability test was conducted in which the sample was placed in an environment of 65°C and 95% humidity and then exposed for 1000 hours. With respect to the sample for evaluation of the humidification durability test after the humidification durability test, the other side to which the polarizing film of the alkali-free glass to which the polarizing film according to Example 1 was bonded was not bonded, through an adhesive layer (thickness of 20 μm) After attaching the polarizing films for Cross Nicols so that the transmission axes of the respective polarizing films are perpendicular to each other, they are placed on the backlight (the polarizing film according to Example 1 is the upper surface), and the polarizing film according to Example 1 is visually observed. Observation was performed to evaluate the presence or absence of bright spots originating from foreign matter.

After a humidification durability test exposed to an environment of 65°C - 95% humidity for 1000 hours, it was found that the polarizing film according to Example 1 had no bright spots originating from foreign matter exceeding 3 mm from the cross section.

Example 2

As the adhesive, an aqueous solution containing an acetoacetyl group-containing polyvinyl alcohol resin (average degree of polymerization: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%) and methylolmelamine at a weight ratio of 3:1 was used. Using this adhesive, a second optical film (triacetyl cellulose film with a hard coat layer (manufactured by Fujifilm Corporation, trade name "TG40UL) is applied to one surface (visible side surface) of the polarizer 1 under a temperature condition of 30 ° C. After attaching ", film thickness 40 micrometer)) with a roll bonding machine, it heat-dried in an oven then, and manufactured the laminated|multilayer film which laminated|stacked the optical film on the single side|surface of a polarizer.

Next, an MCD coater (manufactured by Fuji Machinery Co., Ltd.) (cell shape: honeycomb, gravure roll number: 1000 pieces/inch, rotation speed 140%/line speed) was used on the polarizer 1 side of the laminated film, The adhesive composition adjusted to the compounding amount described in 1 was coated so as to have a thickness of 1 μm, and bonded to the first optical film (cycloolefin film (manufactured by Nippon Zeon Co., Ltd., trade name “ZF14”, film thickness 13 μm)) with a roll machine. After that, from the cycloolefin film side, the visible light was irradiated with an active energy ray irradiation device to cure the adhesive composition, and then hot air dried at 70°C for 3 minutes to obtain a polarizing film (a polarizing film having this configuration was " referred to as “polarizing film configuration (2)”). The thickness of the adhesive layer after drying was 1 µm. The bonding line speed was 25 m/min.

The polarizing film according to Example 2 produced was subjected to a humidification durability test in which it was exposed for 1000 hours in an environment of 65 ° C. to 95% humidity in the same manner as in Example 1, and visually observed the presence or absence of occurrence of bright spots derived from foreign substances. did

After the humidification durability test in which the film was exposed to an environment of 65°C - 95% humidity for 1000 hours, it was found that the polarizing film according to Example 2 had no bright spots originating from foreign matter exceeding 3 mm from the cross section.

Examples 3 to 5, Comparative Examples 1 to 6

The presence or absence of occurrence of bright spots derived from foreign substances was observed by the same method as in Examples 1 and 2, except that the configuration of the polarizing film, the formulation of the adhesive composition, and the type of polarizer were changed to those described in Table 1.

Details of each component described in Table 1 are as follows.

(monofunctional radically polymerizable compound)

Unsaturated fatty acid hydroxyalkyl ester modified ε-caprolactone (monomer component having a hydroxyl group) (trade name "Fraxel FA1DDM", manufactured by Daicel Co., Ltd., molecular weight 230.26, LogPow; 1.06)

・Acryloylmorpholine (trade name “ACMO”, manufactured by Kojin Co., Ltd., molecular weight 141.17, LogPow; -0.20)

Diethyl acrylamide (trade name "DEAA", manufactured by KJ Chemicals, molecular weight 127.18, LogPow; 1.69)

・Lauryl acrylate (trade name "Light Acrylate L-A", manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 240.39, LogPow; 6)

- Isostearyl acrylate (trade name "ISTA", manufactured by Osaka Organic Chemical Industry Co., Ltd., molecular weight 324.5, LogPow; 7.46)

Dicyclopentanyl acrylate (trade name "Pancryl FA-513AS", manufactured by Hitachi Chemical Co., Ltd., molecular weight 206.28, LogPow; 2.58)

(Multifunctional Radical Polymerizable Compound)

PEG400# Diacrylate (trade name "Light Acrylate 9EG-A", manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 536.61, LogPow; -0.1)

・Polypropylene glycol diacrylate (trade name "Aronix M-220", manufactured by Toa Synthetic Co., Ltd., molecular weight 300.35, LogPow; 1.68)

1,9-nonanediol diacrylate (trade name "Light Acrylate 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 268.35, LogPow; 3.68)

Dimethylol-tricyclodecane diacrylate (trade name "Light Acrylate DCP-A", manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 304.38, LogPow; 3.05)

(acrylic oligomer)

34/66 molar ratio copolymerization oligomer of butyl acrylate and methacrylate (trade name "ARUFON UP-1190", manufactured by Toa Synthetic Co., Ltd., molecular weight 1700, LogPow; 1.95)

(initiator)

2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (trade name "Omnirad 907", manufactured by IGM Resins B.V., molecular weight 279.13, LogPow; 2.09)

・Diethylthioxanthone (trade name "KAYACURE DETX-S", manufactured by Nippon Chemical Co., Ltd., molecular weight 268.37, LogPow; 5.12)

In Table 1, "(number of carbon atoms)/(number of oxygen atoms + number of nitrogen atoms)" is calculated based on the above "method for measuring element ratio of adhesive layer", and "average logPow" is "adhesive logPow representing the octanol/water partition coefficient by the weighted average of the mole fractions of the monomer components contained in the composition, "distance from cross section to foreign matter (mm)", "derived from the foreign matter confirmed from the cross section of the polarizing film The distance to the bright point of

10: polarizing film
1: Polarizer
2: water-based adhesive layer
3, 4, 6: optical film
5: adhesive layer
7: adhesive layer

Claims (9)

A polarizing film comprising a polarizer and an adhesive layer adjacent to the polarizer or an optical film other than the polarizer,
The adhesive layer is formed of a cured material layer of an adhesive composition, and the adhesive composition contains 25 parts by weight or more of a monomer component having two or more polymerizable functional groups based on 100 parts by weight of the total amount of the monomer components. , After a humidification durability test exposed to an environment of 65°C - 95% humidity for 1000 hours, a polarizing film characterized by not having a luminescent spot derived from a foreign substance exceeding 3 mm from the cross section. According to claim 1,
The polarizing film in which the adhesive composition contains 40 parts by weight or less of a monomer component having a hydroxyl group when the total amount of the monomer components is 100 parts by weight. According to claim 1 or 2,
The polarizing film in which the said polarizer contains the metal component which can become a divalent metal cation in water. According to claim 3,
A polarizing film in which the metal component is zinc. According to any one of claims 1 to 4,
The polarizing film in which the polarizing film has a polarizer, and an optical film is laminated on at least one surface of the polarizer via a water-based adhesive layer, and an adhesive layer is provided on a surface of the optical film opposite to the water-based adhesive layer. . According to any one of claims 1 to 5,
The polarizing film in which the said adhesive bond layer is what was formed of the hardened|cured material layer of an active energy ray-curable adhesive composition. According to any one of claims 1 to 6,
When the adhesive layer is formed of a cured product layer of an adhesive composition, and the cured product obtained by curing the adhesive composition is immersed in pure water at 23 ° C. for 24 hours,
Formula: {(M2−M1)/M1}×100 (%),
However, M1: weight of cured material before immersion, M2: weight of cured material after immersion,
A polarizing film having a bulk water absorption of less than 10% by weight. At least one polarizing film according to any one of claims 1 to 7 is laminated, the optical film characterized by the above-mentioned. An image display device characterized by using the polarizing film according to any one of claims 1 to 7 and/or the optical film according to claim 8.

Images