JPWO2020100870A1 - Image display device - Google Patents

Abstract

An image display device in which a front transparent member, a polarizing film, and an image display cell are provided in this order via an adhesive layer or an adhesive layer, and the polarizing film is such that iodine is adsorbed and oriented on a polyvinyl alcohol-based film. The polarizing film, the pressure-sensitive adhesive layer, and at least one of the adhesive layers contain a hindered amine-based compound, and the hindered amine-based compound is added to 100 parts by weight of water at 25 ° C. It is a water-soluble hindered amine-based compound that can dissolve 1 part by weight or more, and the polarizing film is a general formula (1): X (% by weight)> 0.01 (in the general formula (1), X is the polarized light. A laminate in which a transparent protective film is bonded to at least one side of the film via the adhesive layer and a glass plate is bonded to both sides of the polarizing film via the adhesive layer is provided at 105 ° C. for 24 hours. Indicates the content of the hindered amine-based compound in the polarizing film in the laminate left in the above). The image display device is excellent in the effect of suppressing a decrease in the single transmittance due to coloring of the polarizing film in a high temperature environment.

Description

The present invention relates to an image display device.

Conventionally, as a polarizing film used for various image display devices such as a liquid crystal display device and an organic EL display device, since it has both high transmittance and high degree of polarization, it has been dyed (such as iodine and dichroic dyes). A polyvinyl alcohol-based film (containing a dichroic substance) is used. The polarizing film is produced by subjecting a polyvinyl alcohol-based film to treatments such as swelling, dyeing, cross-linking, and stretching in a bath, washing treatment, and then drying. Further, the polarizing film is usually used as a polarizing film (polarizing plate) in which a protective film such as triacetyl cellulose is bonded to one side or both sides thereof using an adhesive.

The polarizing film is used as a laminated polarizing film (optical laminate) by laminating other optical layers as needed, and the polarizing film or the laminated polarizing film (optical laminate) is a liquid crystal cell or an organic EL element. Etc., and the front transparent plate (window layer) on the visual side and the front transparent member such as a touch panel are bonded to each other via an adhesive layer or an adhesive layer to form the above-mentioned various image display devices. Used.

In recent years, such various image display devices have been widely used, such as being used as in-vehicle image display devices such as car navigation devices and back monitors in addition to mobile devices such as mobile phones and tablet terminals. There is. Along with this, the polarizing film and the laminated polarizing film are required to have higher durability in a harsher environment (for example, in a high temperature environment) than conventionally required, and such durability is required. A polarizing film for the purpose of securing has been proposed (Patent Document 1).

Further, a dye-based polarizing film using a dichroic dye such as an azo compound is generally higher in temperature and higher than an iodine-based polarizing film (a polarizing film formed by adsorbing and orienting iodine on a polyvinyl alcohol-based film). It is known that the polarizing plate has excellent light resistance under high humidity conditions (Patent Document 2), and in order to improve color loss in the light resistance test of the polarizing plate having the dye-based polarizing film, the polarizing plate is used. It is disclosed that the adhesive used contains a hindered amine compound (Patent Document 3).

Further, in order to increase the heat resistance of the polarizing plate, it is specifically disclosed that a water-insoluble HALS (Hindered Amine Light Stabilizer) is blended with an adhesive containing an epoxy compound (Patent Document 4). ..

Japanese Patent Publication No. 2012-516468 Japanese Unexamined Patent Publication No. 2001-240762 Japanese Unexamined Patent Publication No. 2005-338343 Korean Patent Application Publication No. 10-2015-0114149

On the other hand, as described above, a polarizing film or a laminated polarizing film using an iodine-based polarizing film, which is said to be inferior in light resistance under high temperature and high humidity conditions to a dye-based polarizing film, is exposed to a high temperature environment. In addition, there is a problem that the polarizing film is colored and its single transmittance is lowered. In particular, an image display device configured by laminating the above-mentioned polarizing film or laminated polarizing film between an image display cell and a front transparent member via an adhesive layer or an adhesive layer is used to color the polarizing film. However, there was a problem that the single-unit transmittance was significantly reduced.

In view of the above circumstances, an object of the present invention is to provide an image display device having an excellent effect of suppressing a decrease in single transmittance due to coloring of a polarizing film in a high temperature environment.

That is, the present invention is an image display device in which a front transparent member, a polarizing film, and an image display cell are provided in this order via an adhesive layer or an adhesive layer, and the polarizing film is a polyvinyl alcohol-based film. It has a polarizing film formed by adsorption orientation of iodine, and at least one of the polarizing film, the pressure-sensitive adhesive layer, and the adhesive layer contains a hindered amine-based compound, and the hindered amine-based compound is at 25 ° C. It is a water-soluble hindered amine-based compound that can be dissolved in 1 part by weight or more with respect to 100 parts by weight of water, and the polarizing film is a general formula (1): X (% by weight)> 0.01 (in the general formula (1)). , X is a laminate in which a glass plate is bonded to both sides of a polarizing film in which a transparent protective film is bonded to at least one side of the polarizing film via the adhesive layer. The present invention relates to an image display device satisfying the condition represented by) (indicating the content of a hindered amine-based compound in the polarizing film) in a laminate left at ° C. for 24 hours.

The details of the action mechanism of the effect in the image display device of the present invention are unknown, but it is presumed as follows. However, the present invention does not have to be construed as being limited to this mechanism of action.

In the image display device of the present invention, a front transparent member, a polarizing film, and an image display cell are provided in this order via an adhesive layer or an adhesive layer, and the polarizing film, the adhesive layer, and the adhesive are provided in this order. At least one of the agent layers contains a water-soluble hindered amine-based compound capable of dissolving 1 part by weight or more in 100 parts by weight of water at 25 ° C. Further, the polarizing film has an iodine-based polarizing film formed by adsorption-orientation of iodine on a polyvinyl alcohol-based film. As described in Patent Documents 2 and 3 above, it is generally said that an iodine-based polarizing film is inferior in durability such as heat resistance to a dye-based polarizing film, and the reason for this is included in the polarizing film. It is presumed that this iodine promotes the deterioration phenomenon of polyene formation that occurs in the dehydration reaction of polyvinyl alcohol in a high temperature environment.

On the other hand, the hindered amine-based compound contained in at least one of the polarizing film, the adhesive layer, and the adhesive layer of the present invention has moisture (adhesiveness) existing inside the image display device when exposed to a high temperature environment. Since it moves (retains) inside the image display device together with (moisture existing in the agent layer, adhesive layer, etc.), it is presumed that a part of the water-soluble hindered amine-based compound permeates the above-mentioned iodine-based polarizing film. As a result, it is presumed that the water-soluble hindered amine compound in the polarizing film can efficiently capture the radicals generated in the above polyene reaction in a high temperature environment. Therefore, the image display apparatus of the present invention is used for coloring the polarizing film. It is possible to suppress a decrease in the single transmittance due to.

It is a schematic cross-sectional view which shows one form of an image display device. It is a schematic cross-sectional view which shows one form of the single-sided protective polarizing film. It is a schematic cross-sectional view which shows one form of the double-sided protective polarizing film.

FIG. 1 is a schematic cross-sectional view showing a form of the image display device of the present invention. In the image display device 100 of FIG. 1, the front transparent member 80 and the polarizing film 10 are bonded to each other via the pressure-sensitive adhesive layer or the adhesive layer 20, and the image display cell 90 and the polarizing film 10 are bonded to the pressure-sensitive adhesive layer or the bonding film 10. They are bonded together via the agent layer 30.

FIG. 2 is a schematic cross-sectional view showing one form of the single-sided protective polarizing film of the present invention. The single-sided protective polarizing film 101 of FIG. 2 shows one aspect of the polarizing film 10 in which the polarizing film 11 and the transparent protective film 13 are bonded to each other via an adhesive layer or an adhesive layer 50.

FIG. 3 is a schematic cross-sectional view showing one form of the double-sided protective polarizing film of the present invention. In the double-sided protective polarizing film 102 of FIG. 3, the polarizing film 11 and the transparent protective film 13 are bonded and exposed via an adhesive layer or an adhesive layer 50, and the polarizing film 11 and the transparent protective film 12 are adhesives. An aspect of a polarizing film 10 bonded via a layer or an adhesive layer 40 is shown.

In the image display device of the present invention, a front transparent member, a polarizing film, and an image display cell are provided in this order via an adhesive layer or an adhesive layer, and the polarizing film, the adhesive layer, and the adhesive are provided in this order. At least one of the agent layers contains a hindered amine-based compound, and the hindered amine-based compound is a water-soluble hindered amine-based compound that can be dissolved in 1 part by weight or more with respect to 100 parts by weight of water at 25 ° C. The hindered amine compound may be used alone or in combination of two or more.

The hindered amine compound moves (retains) inside the image display device together with water existing inside the image display device (moisture existing in the adhesive layer, the adhesive layer, etc.) to color the polarizing film in a high temperature environment. From the viewpoint of suppressing the decrease in single-unit transmittance due to the above, it is preferable that 2 parts by weight or more can be dissolved in 100 parts by weight of water at 25 ° C, and more preferably 5 parts by weight or more can be dissolved in 100 parts by weight of water at 25 ° C. ..

Further, the hindered amine compound preferably has a molecular weight of 1000 or less, more preferably 500 or less, and further preferably 300 or less, from the viewpoint of efficiently capturing radicals generated in the polyene reaction. preferable.

（一般式（１）中、Ｒ^１は、オキシラジカル、水素原子、ヒドロキシ基、または炭素原子数が１〜３０のアルキル基、ヒドロキシアルキル基、ヒドロキシアルコキシ基、もしくはアルコキシ基を表し、Ｒ^２からＲ^５は、独立して、水素原子、または炭素原子数が１〜１０のアルキル基を表し、ｎは０または１を表す。）なお、一般式（１）中の、点線部の左は任意の有機基を示す。<Hindered amine compounds>
The hindered amine compound of the present invention is a secondary amine or a tertiary amine in which an alkyl group is substituted on a carbon adjacent to the amino group to sterically protect the amino group. For example, an organic group having the following structure Examples thereof include compounds having. The example compound may include a structure that cannot be dissolved by 1 part by weight or more in 100 parts by weight of water at 25 ° C., but those skilled in the art will take into consideration the common general knowledge and the example compound. However, it can be immediately confirmed whether or not 1 part by weight or more can be dissolved in 100 parts by weight of water at 25 ° C.

(In the general formula (1), R ¹ represents an oxy radical, a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, a hydroxyalkoxy group, or an alkoxy group, and is derived from R ^2. R ⁵ independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n represents 0 or 1.) Note that the left side of the dotted line in the general formula (1) is arbitrary. Indicates an organic group of.

The hindered amine compounds are known compounds and are described, for example, in columns 5-11 of US Pat. No. 4,619,956 and columns 3-5 of US Pat. No. 4,839,405. Included are 2,2,6,6-tetraalkylpiperidin compounds, or acid addition salts thereof, or complexes of them with metal compounds, as described above.

（一般式（２）中、Ｒ^１は、オキシラジカル、水素原子、ヒドロキシ基、または炭素原子数が１〜３０のアルキル基、ヒドロキシアルキル基、ヒドロキシアルコキシ基、もしくはアルコキシ基を表し、Ｒ^２からＲ^５は、独立して、水素原子、または炭素原子数が１〜１０のアルキル基を表し、Ｒ^６は水素原子、または炭素原子数が１〜１０のアルキル基、アシル基、もしくはアリール基を表し、ｎは０または１を表す。）

（一般式（３）中、Ｒ^１からＲ^５、およびｎは、上記と同様であり、Ｒ^７およびＲ^８は、独立して、水素原子、または炭素原子数が１〜１０のアルキル基、アシル基、もしくはアリール基を表す。）

（一般式（４）中、Ｒ^１からＲ^５、およびｎは、上記と同様であり、Ｒ^９からＲ^１１は、独立して、水素原子、または炭素原子数が１〜１０のアルキル基、アシル基、アミノ基、アルコキシ基、ヒドロキシ基、もしくはアリール基を表す。）

（一般式（５）中、Ｒ^１からＲ^５、およびｎは、上記と同様であり、Ｒ^１２は、水素原子、または炭素原子数が１〜１０のアルキル基、アミノ基、アルコキシ基、ヒドロキシ基、もしくはアリール基を表す。）Examples of the compound having an organic group include compounds represented by the following general formulas (2) to (5).

(In the general formula (2), R ¹ represents an oxy radical, a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, a hydroxyalkoxy group, or an alkoxy group, and is derived from R ^2. R ⁵ independently represents a hydrogen atom or an alkyl radical having 1 to 10 carbon atoms, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an acyl group, or an aryl group. Represents, n represents 0 or 1.)

(In the general formula (3), R ¹ to R ⁵ and n are the same as above, and R ⁷ and R ⁸ are independently hydrogen atoms or alkyl groups having 1 to 10 carbon atoms. Represents an acyl group or an aryl group.)

(In the general formula (4), R ¹ to R ⁵ and n are the same as above, and R ⁹ to R ¹¹ are independently hydrogen atoms or alkyl groups having 1 to 10 carbon atoms. Represents an acyl group, an amino group, an alkoxy group, a hydroxy group, or an aryl group.)

(In the general formula (5), R ¹ to R ⁵ and n are the same as above, and R ¹² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an amino group, an alkoxy group and a hydroxy group. Represents a group or an aryl group.)

In the general formulas (1) to (5), R ¹ is preferably an oxy radical, a hydrogen atom, a hydroxy group, or an alkyl group from the viewpoint of efficiently suppressing accelerated deterioration of polyvinyl alcohol, and is preferably an oxy radical group. Is more preferable. Further, in the general formulas (1) to (5), R ² to R ⁵ are preferably alkyl groups having 1 to 6 carbon atoms from the viewpoint of availability and water solubility, and have carbon atoms. Is more preferably 1 to 3 alkyl groups. Further, in the general formula (2), from the viewpoint of availability and water solubility, R ⁶ is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and more preferably a hydrogen atom. preferable. Further, in the general formula (3), from the viewpoint of availability and water solubility, it is preferable that R ⁷ and R ⁸ are independently hydrogen atoms or alkyl groups having 1 to 10 carbon atoms, and hydrogen. It is more preferably an atom. Further, in the general formula (4), from the viewpoint of availability and water solubility, R ⁹ to R ¹¹ are preferably hydrogen atoms or alkyl groups having 1 to 10 carbon atoms. Further, in the general formula (5), R ¹² is preferably a hydroxy group, an amino group, or an alkoxy group from the viewpoint of availability and water solubility. In the general formulas (1) to (5), n is preferably 1 from the viewpoint of availability.

<Polarizing film>
The polarizing film of the present invention has a polarizing film formed by adsorbing and orienting iodine on a polyvinyl alcohol-based film.

As the polyvinyl alcohol (PVA) -based film, one having translucency in the visible light region and dispersing and adsorbing iodine can be used without particular limitation. Further, the PVA-based film usually used as a raw material preferably has a thickness of about 1 to 100 μm, more preferably about 1 to 50 μm, and preferably a width of about 100 to 5000 mm.

Examples of the material of the polyvinyl alcohol-based film include polyvinyl alcohol or a derivative thereof. Examples of the polyvinyl alcohol derivative include polyvinyl formal, polyvinyl acetal; olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, and alkyl esters and acrylamides thereof. Can be mentioned. The polyvinyl alcohol preferably has an average degree of polymerization of about 100 to 10,000, more preferably about 1,000 to 10,000, and even more preferably about 1,500 to 4,500. .. Further, the polyvinyl alcohol preferably has a saponification degree of about 80 to 100 mol%, and more preferably about 95 mol% to 99.95 mol. The average degree of polymerization and the degree of saponification can be determined according to JIS K 6726.

The polyvinyl alcohol-based film may contain additives such as a plasticizer and a surfactant. Examples of the plasticizer include polyols and condensates thereof such as glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol. The amount of the additive used is not particularly limited, but is preferably about 20% by weight or less in the polyvinyl alcohol-based film, for example.

The polarizing film preferably has an iodine content of 1% by weight or more and 15% by weight or less. From the viewpoint of suppressing color loss during the durability test, the polarizing film preferably has an iodine content of 1.5% by weight or more, more preferably 2% by weight or more, and From the viewpoint of preventing polyene formation, it is preferably 12% by weight or less, and more preferably 10% by weight or less.

When the polarizing film contains the hindered amine compound, the content of the hindered amine compound is preferably 20% by weight or less. The content of the hindered amine compound in the polarizing film is preferably 0.005% by weight or more, preferably 0.01% by weight, from the viewpoint of suppressing a decrease in the single transmittance due to coloring of the polarizing film in a high temperature environment. % Or more, more preferably 0.1% by weight or more, more preferably 15% by weight or less, more preferably 12% by weight or less, and 10% by weight or less. It is more preferable to have.

<Manufacturing method of polarizing film>
The method for producing a polarizing film is obtained by subjecting the polyvinyl alcohol-based film to an arbitrary swelling step and a washing step, and at least a dyeing step, a crosslinking step, and a stretching step. When the polarizing film contains the hindered amine compound, the treatment bath in any one or more of the swelling step, the washing step, the dyeing step, the cross-linking step, and the stretching step is the hindered amine. It may contain a system compound. The content of the hindered amine compound contained in the polarizing film and the content of the iodine are the hindered amine compound contained in any of the treatment baths in the swelling step, the dyeing step, the cross-linking step, the stretching step and the washing step. It can be controlled by the concentration of iodine, the concentration of iodine, potassium iodide, etc., the treatment temperature and the treatment time in each of the above treatment baths. In particular, when the washing step is performed after the dyeing step, the cross-linking step, and the stretching step, the washing step includes a hindered amine compound or a hindered amine compound in consideration of the treatment conditions in the dyeing step, the cross-linking step, the stretching step, and the like. From the viewpoint that components such as iodine can be eluted from the polyvinyl alcohol-based film or adsorbed on the polyvinyl alcohol-based film, it is easy to adjust the content of the hindered amine-based compound and the content of the iodine to a desired range.

In addition, each treatment bath in the swelling step, the dyeing step, the cross-linking step, the stretching step, and the washing step contains additives such as zinc salts, pH adjusters, pH buffers, and other salts. You may. Examples of the zinc salt include zinc halides such as zinc chloride and zinc iodide; and inorganic zinc salts such as zinc sulfate and zinc acetate. Examples of the pH adjuster include strong acids such as hydrochloric acid, sulfuric acid and nitric acid, and strong bases such as sodium hydroxide and potassium hydroxide. Examples of the pH buffer include carboxylic acids such as acetic acid, oxalic acid and citric acid and salts thereof, and inorganic weak acids such as phosphoric acid and carbonic acid and salts thereof. Examples of the other salts include chlorides such as sodium chloride, potassium chloride and barium chloride, nitrates such as sodium nitrate and potassium nitrate, sulfates such as sodium sulfate and potassium sulfate, and alkali metals and alkaline earth metals. Examples include salt.

The concentration of the hindered amine compound contained in any of the treatment baths cannot be unconditionally determined because it is affected by the number of treatments, the treatment time, the treatment temperature, etc. of each treatment, but the inclusion of the hindered amine compound in the polarizing film From the viewpoint of efficiently controlling the amount, it is usually preferably 0.01% by weight or more, more preferably 0.05% by weight or more, further preferably 0.1% by weight or more, and , 30% by weight or less, more preferably 20% by weight or less, still more preferably 10% by weight or less.

The swelling step is a treatment step of immersing the polyvinyl alcohol-based film in a swelling bath, and can remove stains and blocking agents on the surface of the polyvinyl alcohol-based film, and dyes the polyvinyl alcohol-based film by swelling it. Unevenness can be suppressed. As the swelling bath, a medium containing water as a main component, such as water, distilled water, and pure water, is usually used. A surfactant, alcohol, or the like may be appropriately added to the swelling bath according to a conventional method.

The temperature of the swelling bath is preferably about 10 to 60 ° C, more preferably about 15 to 45 ° C, and even more preferably about 18 to 35 ° C. The immersion time in the swelling bath cannot be unconditionally determined because the degree of swelling of the polyvinyl alcohol-based film is affected by the temperature of the swelling bath, but is preferably about 5 to 300 seconds, preferably 10 to 200 seconds. It is more preferably about 20 to 100 seconds. The swelling step may be carried out only once, or may be carried out a plurality of times as needed.

The dyeing step is a treatment step of immersing the polyvinyl alcohol-based film in a dyeing bath (iodine solution), and iodine can be adsorbed and oriented on the polyvinyl alcohol-based film. The iodine solution is usually preferably an aqueous iodine solution and contains iodine and iodide as a solubilizing agent. The iodide includes potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, and iodide. Examples include titanium. Among these, potassium iodide is preferable from the viewpoint of controlling the content of potassium in the polarizing film.

In the dyeing bath, the iodine concentration is preferably about 0.01 to 1% by weight, more preferably about 0.02 to 0.5% by weight. In the dyeing bath, the concentration of the iodide is preferably about 0.01 to 20% by weight, more preferably about 0.05 to 10% by weight, and about 0.1 to 5% by weight. It is more preferable to have.

The temperature of the dyeing bath is preferably about 10 to 50 ° C., more preferably about 15 to 45 ° C., and even more preferably about 18 to 30 ° C. The immersion time in the dyeing bath cannot be unconditionally determined because the degree of dyeing of the polyvinyl alcohol-based film is affected by the temperature of the dyeing bath, but is preferably about 10 to 300 seconds, preferably about 20 to 240 seconds. More preferably. The dyeing step may be carried out only once, or may be carried out a plurality of times as needed.

The cross-linking step is a treatment step of immersing the polyvinyl alcohol-based film in a treatment bath (cross-linking bath) containing a boron compound. The polyvinyl alcohol-based film is cross-linked by the boron compound, and iodine molecules or dye molecules are cross-linked. Can be adsorbed on the structure. Examples of the boron compound include boric acid, borate, borax and the like. The cross-linked bath is generally an aqueous solution, but may be, for example, a mixed solution of an organic solvent and water that is miscible with water. Further, the crosslinked bath may contain potassium iodide from the viewpoint of controlling the content of potassium in the polarizing film.

In the crosslinked bath, the concentration of the boron compound is preferably about 1 to 15% by weight, more preferably about 1.5 to 10% by weight, and more preferably about 2 to 5% by weight. preferable. When potassium iodide is used in the cross-linking bath, the concentration of potassium iodide in the cross-linking bath is preferably about 1 to 15% by weight, preferably about 1.5 to 10% by weight. More preferably, it is about 2 to 5% by weight.

The temperature of the cross-linking bath is preferably about 20 to 70 ° C, more preferably about 30 to 60 ° C. The immersion time in the cross-linking bath cannot be unconditionally determined because the degree of cross-linking of the polyvinyl alcohol-based film is affected by the temperature of the cross-linking bath, but is preferably about 5 to 300 seconds, preferably 10 to 200 seconds. More preferably. The cross-linking step may be carried out only once, or may be carried out a plurality of times as needed.

The stretching step is a treatment step of stretching a polyvinyl alcohol-based film to a predetermined magnification in at least one direction. Generally, a 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 adopted. The stretching step may be carried out only once, or may be carried out a plurality of times as needed. The stretching step may be performed at any stage in the production of the polarizing film.

As the treatment bath (stretching bath) in the wet stretching method, a solvent such as water or a mixed solution of water and an organic solvent miscible with water can be usually used. The stretching bath may contain potassium iodide from the viewpoint of controlling the content of the potassium in the polarizing film. When potassium iodide is used in the stretching bath, the concentration of potassium iodide in the stretching bath is preferably about 1 to 15% by weight, more preferably about 2 to 10% by weight, and 3 More preferably, it is about 6% by weight. Further, the treatment bath (stretching bath) can contain the boron compound from the viewpoint of suppressing film breakage during stretching. In this case, the concentration of the boron compound in the stretching bath is 1 to 15. It is preferably about% by weight, more preferably about 1.5 to 10% by weight, and even more preferably about 2 to 5% by weight.

The temperature of the stretching bath is preferably about 25 to 80 ° C, more preferably about 40 to 75 ° C, and even more preferably about 50 to 70 ° C. The immersion time in the stretching bath cannot be unconditionally determined because the degree of stretching of the polyvinyl alcohol-based film is affected by the temperature of the stretching bath, but is preferably about 10 to 800 seconds, preferably about 30 to 500 seconds. More preferably. The stretching treatment in the wet stretching method may be performed together with any one or more of the swelling step, the dyeing step, the cross-linking step, and the washing step.

Examples of the dry stretching method include an inter-roll stretching method, a heating roll stretching method, and a compression stretching method. The dry stretching method may be performed together with the drying step.

The total draw ratio (cumulative draw ratio) applied to the polyvinyl alcohol-based film can be appropriately set depending on the intended purpose, but is preferably about 2 to 7 times, and preferably about 3 to 6.8 times. More preferably, it is about 3.5 to 6.5 times.

The cleaning step is a treatment step of immersing the polyvinyl alcohol-based film in a washing bath, and can remove foreign substances remaining on the surface of the polyvinyl alcohol-based film or the like. As the washing bath, a medium containing water as a main component, such as water, distilled water, and pure water, is usually used. Further, from the viewpoint of controlling the content of potassium in the polarizing film, the washing bath may contain potassium iodide, and in this case, the concentration of potassium iodide in the washing bath is 1 to 10 weight by weight. It is preferably about%, more preferably about 1.5 to 4% by weight, and even more preferably about 1.8 to 3.8% by weight.

The temperature of the washing bath is preferably about 5 to 50 ° C., more preferably about 10 to 40 ° C., and even more preferably about 15 to 30 ° C. The immersion time in the washing bath cannot be unconditionally determined because the degree of washing of the polyvinyl alcohol-based film is affected by the temperature of the washing bath, but is preferably about 1 to 100 seconds, preferably 2 to 50 seconds. It is more preferably about 3 to 20 seconds. The swelling step may be carried out only once, or may be carried out a plurality of times as needed.

The method for producing a polarizing film may include a drying step. The drying step is a step of drying the polyvinyl alcohol-based film washed in the washing step to obtain a polarizing film, and drying obtains a polarizing film having a desired moisture content. The drying is carried out by any suitable method, and examples thereof include natural drying, blast drying, and heat drying.

The drying temperature is preferably about 20 to 150 ° C, more preferably about 25 to 100 ° C. Further, the drying time cannot be unconditionally determined because the degree of drying of the polarizing film is affected by the drying temperature, but is preferably about 30 to 600 seconds, more preferably about 60 to 300 seconds. preferable. The drying step may be carried out only once, or may be carried out a plurality of times as needed.

The thickness of the polarizing film is preferably about 1 to 50 μm, more preferably about 1 to 25 μm. In particular, in order to obtain a polarizing film having a thickness of 8 μm or less, a laminate containing a polyvinyl alcohol-based resin layer formed on a resin base material such as a thermoplastic resin is used as the polyvinyl alcohol-based film. The method for producing a polarizing film can be applied.

<Manufacturing method of polarizing film (thin polarizing film)>
The method for producing a polarizing film (thin polarizing film) is a step of forming a polyvinyl alcohol-based resin layer containing a polyvinyl alcohol-based resin on one side of a long thermoplastic resin base material to prepare a laminate, and obtaining the same. While transporting the laminated body in the longitudinal direction, an arbitrary insolubilization treatment step, a cross-linking treatment step, and a cleaning treatment step, and at least an aerial auxiliary stretching treatment step, a dyeing treatment step, and an underwater stretching treatment step are performed on the laminate. It is obtained by applying. When the polarizing film contains the hindered amine compound, in any one or more of the insolubilization treatment step, the cross-linking treatment step, the cleaning treatment step, the dyeing treatment step, and the underwater stretching treatment step. The treatment bath may contain the hindered amine compound. The content of the hindered amine compound and the content of iodine contained in the polarizing film are each in the insolubilization treatment step, the cross-linking treatment step, the cleaning treatment step, the dyeing treatment step, and the underwater stretching treatment step. It can be controlled by the concentration of the hindered amine compound contained in any of the treatment baths, the concentration of iodine, potassium iodide, etc., the treatment temperature and the treatment time in each of the above treatment baths. In particular, when the cleaning treatment step is performed, the cleaning treatment step elutes components such as hindered amine compounds and iodine from the polyvinyl alcohol-based film in consideration of the treatment conditions in the dyeing treatment step, the drawing treatment step in water, and the like. Alternatively, from the viewpoint that it can be adsorbed on a polyvinyl alcohol-based film, it is easy to adjust the content of the hindered amine-based compound and the content of the iodine to a desired range.

The concentration of the hindered amine compound contained in any of the treatment baths cannot be unconditionally determined because it is affected by the number of treatments, the treatment time, the treatment temperature, etc. of each treatment, but the inclusion of the hindered amine compound in the polarizing film From the viewpoint of efficiently controlling the amount, it is usually preferably 0.01% by weight or more, more preferably 0.05% by weight or more, further preferably 0.1% by weight or more, and , 30% by weight or less, more preferably 25% by weight or less, still more preferably 20% by weight or less.

<Process to prepare the laminate>
Any suitable method is adopted as the method for producing the laminate. For example, a coating liquid containing the polyvinyl alcohol-based resin (PVA-based resin) is applied to the surface of the thermoplastic resin base material and dried. There is a way to do it. The thickness of the thermoplastic resin base material is preferably about 20 to 300 μm, more preferably about 50 to 200 μm. The thickness of the PVA-based resin layer is preferably about 3 to 40 μm, and more preferably about 3 to 20 μm.

The thermoplastic resin base material preferably has a water absorption rate of about 0.2% or more, preferably 0.3, from the viewpoint of absorbing water, significantly reducing the stretching stress, and being able to stretch at a high magnification. More preferably, it is about% or more. On the other hand, the thermoplastic resin base material has a water absorption rate of 3 from the viewpoint that the dimensional stability of the thermoplastic resin base material is remarkably lowered and problems such as deterioration of the appearance of the obtained polarizing film can be prevented. It is preferably about% or less, and more preferably about 1% or less. The water absorption rate can be adjusted, for example, by introducing a modifying group into the constituent material of the thermoplastic resin base material. The water absorption rate is a value obtained according to JIS K 7209.

The thermoplastic resin base material has a glass transition temperature (Tg) of about 120 ° C. or less from the viewpoint of being able to sufficiently secure the stretchability of the laminate while suppressing the crystallization of the PVA-based resin layer. Is preferable. Further, in consideration of plasticizing the thermoplastic resin base material with water and satisfactorily stretching in water, the glass transition temperature (Tg) is more preferably about 100 ° C. or lower, and more preferably about 90 ° C. or lower. Is even more preferable. On the other hand, the glass transition temperature of the thermoplastic resin base material is a viewpoint that a good laminate can be produced by preventing problems such as deformation of the thermoplastic resin base material when the coating liquid is applied and dried. Therefore, it is preferably about 60 ° C. or higher. The glass transition temperature can be adjusted, for example, by introducing a modifying group into the constituent material of the thermoplastic resin base material or heating with a crystallization material. The glass transition temperature (Tg) is a value obtained according to JIS K 7121.

Any suitable thermoplastic resin can be adopted as the constituent material of the thermoplastic resin base material. Examples of the thermoplastic resin include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. And so on. Among these, norbornene-based resin and amorphous (amorphous) polyethylene terephthalate-based resin are preferable, and further, the thermoplastic resin base material is extremely excellent in stretchability and crystallization during stretching can be suppressed. , Amorphous (amorphous) polyethylene terephthalate resin is preferably used. Examples of the amorphous (amorphous) polyethylene terephthalate resin include a copolymer containing isophthalic acid and / or cyclohexanedicarboxylic acid as a dicarboxylic acid, and a copolymer containing cyclohexanedimethanol or diethylene glycol as a glycol.

The thermoplastic resin base material may be surface-treated (for example, corona treatment or the like) before forming the PVA-based resin layer, or an easily adhesive layer may be formed on the thermoplastic resin base material. .. By performing such a treatment, the adhesion between the thermoplastic resin base material and the PVA-based resin layer can be improved. Further, the thermoplastic resin base material may be stretched before forming the PVA-based resin layer.

The coating liquid is a solution in which a PVA-based resin is dissolved in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols, polyhydric alcohols such as trimethylpropane, and amines such as ethylenediamine and diethylenetriamine. preferable. These can be used alone or in combination of two or more. The PVA-based resin concentration of the coating liquid is preferably about 3 to 20 parts by weight with respect to 100 parts by weight of the solvent from the viewpoint of being able to form a uniform coating film in close contact with the thermoplastic resin base material. ..

The coating liquid preferably contains a halide from the viewpoint of improving the orientation of the polyvinyl alcohol molecules by stretching. As the halide, any suitable halide can be adopted, and examples thereof include iodide and sodium chloride. Examples of the iodide include potassium iodide, sodium iodide, lithium iodide and the like, and potassium iodide is preferable. The concentration of the halide in the coating liquid is preferably about 5 to 20 parts by weight, more preferably about 10 to 15 parts by weight, based on 100 parts by weight of the PVA-based resin.

Further, an additive may be added to the coating liquid. Examples of the additive include plasticizers such as ethylene glycol and glycerin; and surfactants such as nonionic surfactants.

Any suitable method can be adopted as the coating method of the coating liquid, and for example, a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, and a spray coating method can be adopted. , Knife coat method (comma coat method, etc.) and the like. The drying temperature of the coating liquid is preferably about 50 ° C. or higher.

<Aerial auxiliary stretching process>
Since the aerial auxiliary stretching treatment step can be stretched while suppressing the crystallization of the thermoplastic resin base material, the laminated body can be stretched at a high magnification. The stretching method in the aerial auxiliary stretching treatment step may be fixed-end stretching (for example, a method of stretching using a tenter stretching machine) or free-end stretching (for example, uniaxial stretching through a laminate between rolls having different peripheral speeds). Method) may be used, but free-end stretching is preferable from the viewpoint of obtaining high optical characteristics.

The stretching ratio in the aerial auxiliary stretching treatment step is preferably about 2 to 3.5 times. The aerial auxiliary stretching treatment may be performed in one step or in multiple steps. When performed in multiple stages, the draw ratio is the product of the draw ratios of each stage.

The stretching temperature in the aerial auxiliary stretching treatment step can be set to an arbitrary appropriate value depending on the material for forming the thermoplastic resin base material, the stretching method, and the like. For example, the glass transition temperature of the thermoplastic resin base material. It is preferably (Tg) or higher, more preferably the glass transition temperature (Tg) + 10 ° C. or higher, and even more preferably the glass transition temperature (Tg) + 15 ° C. or higher. On the other hand, the upper limit of the stretching temperature is from the viewpoint of suppressing the rapid progress of crystallization of the PVA-based resin and suppressing defects due to crystallization (for example, hindering the orientation of the PVA-based resin layer due to stretching). , It is preferably about 170 ° C.

<Insolubilization process>
If necessary, an insolubilization treatment step may be performed after the aerial auxiliary stretching treatment step and before the dyeing treatment step or the underwater stretching treatment step. The insolubilization treatment step is typically performed by immersing a PVA-based resin layer in an aqueous boric acid solution. By performing the insolubilization treatment step, it is possible to impart water resistance to the PVA-based resin layer and prevent the orientation of PVA from deteriorating when immersed in water. The concentration of the boric acid aqueous solution is preferably about 1 to 5 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the insolubilizing bath is preferably about 20 to 50 ° C.

<Dyeing process>
The dyeing treatment step is performed by dyeing the PVA-based resin layer with iodine. Examples of the adsorption method include a method of immersing a PVA-based resin layer (laminate) in a dyeing solution containing iodine, a method of applying the dyeing solution to the PVA-based resin layer, and a method of applying the dyeing solution to the PVA-based resin layer. Examples thereof include a method of spraying, and a method of immersing a PVA-based resin layer (laminate) in a dyeing solution containing iodine is preferable.

The blending amount of iodine in the dyeing bath is preferably about 0.05 to 0.5 parts by weight with respect to 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add the iodide to an aqueous iodine solution. The blending amount of the iodide is preferably about 0.1 to 10 parts by weight, more preferably about 0.3 to 5 parts by weight, based on 100 parts by weight of water. The liquid temperature of the dyeing bath is preferably about 20 to 50 ° C. in order to suppress the dissolution of the PVA-based resin. Further, the immersion time is preferably about 5 seconds to 5 minutes, more preferably about 30 seconds to 90 seconds, from the viewpoint of ensuring the transmittance of the PVA-based resin layer. From the viewpoint of obtaining a polarizing film having good optical characteristics, the ratio of the iodine and iodide contents in the iodine aqueous solution is preferably about 1: 5 to 1:20, preferably about 1: 5 to 1:10. More preferably.

<Crosslinking process>
If necessary, a cross-linking treatment step may be performed after the dyeing treatment step and before the underwater stretching treatment step. The cross-linking treatment step is typically performed by immersing a PVA-based resin layer in an aqueous boric acid solution. By performing the cross-linking treatment step, water resistance can be imparted to the PVA-based resin layer, and the orientation of PVA can be prevented from being lowered when immersed in high-temperature water by subsequent stretching in water. The boric acid concentration of the boric acid aqueous solution is preferably about 1 to 5 parts by weight with respect to 100 parts by weight of water. Further, when the cross-linking treatment step is performed, it is preferable to further add the iodide to the cross-linking bath. By blending the iodide, the elution of iodine adsorbed on the PVA-based resin layer can be suppressed. The blending amount of the iodide is preferably about 1 to 5 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the cross-linked bath (boric acid aqueous solution) is preferably about 20 to 50 ° C.

<Underwater stretching process>
The underwater stretching treatment step is performed by immersing the laminate in a stretching bath. According to the underwater stretching treatment step, the thermoplastic resin base material or the PVA-based resin layer can be stretched at a temperature lower than the glass transition temperature (typically about 80 ° C.), and the PVA-based resin layer is crystallized. Can be stretched at a high magnification while suppressing the above. The stretching method in the underwater stretching treatment step may be fixed-end stretching (for example, a method of stretching using a tenter stretching machine) or free-end stretching (for example, a method of uniaxial stretching through a laminate between rolls having different peripheral speeds). ), But free-end stretching is preferable from the viewpoint of obtaining high optical characteristics.

The underwater stretching treatment step is preferably performed by immersing the laminate in a boric acid aqueous solution (boric acid water stretching). By using an aqueous boric acid solution as the stretching bath, it is possible to impart rigidity to withstand the tension applied during stretching and water resistance that does not dissolve in water to the PVA-based resin layer. The boric acid concentration of the boric acid aqueous solution is preferably 1 to 10 parts by weight, more preferably 2.5 to 6 parts by weight, based on 100 parts by weight of water. In addition, iodide may be blended in the stretching bath (boric acid aqueous solution). The liquid temperature of the stretching bath is preferably about 40 to 85 ° C, more preferably about 60 ° C to 75 ° C. The immersion time of the laminate in the stretching bath is preferably about 15 seconds to 5 minutes.

The stretching ratio in the underwater stretching treatment step is preferably about 1.5 times or more, and more preferably about 3 times or more.

The total draw ratio of the laminated body is preferably about 5 times or more, and more preferably about 5.5 times or more with respect to the original length of the laminated body.

<Washing process>
It is preferable to perform a washing treatment step after the underwater stretching treatment step. The cleaning treatment step is typically performed by immersing a PVA-based resin layer in an aqueous potassium iodide solution.

Further, each treatment bath in the dyeing treatment step, the underwater stretching treatment step, the insolubilization treatment step, the cross-linking treatment step, and the cleaning treatment step includes zinc salts, pH adjusters, pH buffers, and other salts. Additives may be contained. Examples of the zinc salt include zinc halides such as zinc chloride and zinc iodide; and inorganic zinc salts such as zinc sulfate and zinc acetate. Examples of the pH adjuster include strong acids such as hydrochloric acid, sulfuric acid and nitric acid, and strong bases such as sodium hydroxide and potassium hydroxide. Examples of the pH buffer include carboxylic acids such as acetic acid, oxalic acid and citric acid and salts thereof, and inorganic weak acids such as phosphoric acid and carbonic acid and salts thereof. Examples of the other salts include chlorides such as sodium chloride, potassium chloride and barium chloride, nitrates such as sodium nitrate and potassium nitrate, sulfates such as sodium sulfate and potassium sulfate, and alkali metals and alkaline earth metals. Examples include salt.

<Adhesive layer>
As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the present invention, various pressure-sensitive adhesives used in polarizing films can be applied. For example, rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and urethane-based pressure-sensitive adhesives. , Vinyl alkyl ether adhesive, polyvinyl alcohol adhesive, polyvinyl porolidone adhesive, polyacrylamide adhesive, cellulose adhesive and the like. Among these, acrylic adhesives are preferable. The acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer, and examples thereof include the acrylic pressure-sensitive adhesive described in JP-A-2017-75998.

The acrylic polymer in the acrylic pressure-sensitive adhesive has a monomer unit of a (meth) acrylic acid alkyl ester as a main skeleton. As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used, and the content of the (meth) acrylic acid alkyl ester is the base polymer. It is preferably 40% by weight or more, more preferably 60% by weight or more, based on the total amount of the constituent monomer components. Further, from the viewpoint of adjusting the adhesiveness of the pressure-sensitive adhesive, a monomer unit such as a nitrogen-containing monomer unit or a hydroxy group-containing monomer may be contained. Further, a cross-linking agent may be used to form a cross-linked structure in the pressure-sensitive adhesive layer. Examples of the cross-linking agent include an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an oxazoline-based cross-linking agent, an aziridine-based cross-linking agent, and a carbodiimide-based cross-linking agent. Commonly used cross-linking agents, metal chelate-based cross-linking agents and the like can be used. The amount of the cross-linking agent used is usually 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the base polymer.

From the viewpoint of adjusting the adhesive strength, the pressure-sensitive adhesive includes silane coupling agents; terpene-based pressure-sensitive adhesives, styrene-based pressure-sensitive adhesives, phenol-based pressure-sensitive adhesives, rosin-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and the like. A tackifier may be added. Further, from the viewpoint of improving the light resistance, an ultraviolet absorber may be added. In addition to the above-exemplified components, the pressure-sensitive adhesive includes additives such as plasticizers, softeners, deterioration inhibitors, fillers, colorants, antioxidants, surfactants, and antistatic agents. Can be used as long as it does not impair.

As a method for forming the pressure-sensitive adhesive layer, for example, a method in which the pressure-sensitive adhesive is applied to a separator or the like that has been peeled off and dried to form a pressure-sensitive adhesive layer and then transferred to a polarizing film or the like, or the pressure-sensitive adhesive is polarized. Examples thereof include a method of applying to a film or the like and drying to form an adhesive layer. The thickness of the pressure-sensitive adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm, preferably about 2 to 50 μm.

<Adhesive layer>
As the adhesive for forming the adhesive layer of the present invention, various adhesives used for polarizing films can be applied, for example, isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, and vinyl-based latexs. Examples include system and water-based polyester. These adhesives are usually used as an adhesive (water-based adhesive) composed of an aqueous solution, and contain 0.5 to 60% by weight of a solid content. Among these, a polyvinyl alcohol-based adhesive is preferable, and an acetoacetyl group-containing polyvinyl alcohol-based adhesive is more preferable.

The water-based adhesive may contain a cross-linking agent. As the cross-linking agent, a compound having at least two functional groups in one molecule having reactivity with a component such as a polymer constituting the adhesive is usually used, and for example, alkylenediamines; isocyanates; epoxies; Aldehydes; examples include amino-formaldehyde such as methylolurea and methylolmelamine. The blending amount of the cross-linking agent in the adhesive is usually about 10 to 60 parts by weight with respect to 100 parts by weight of the components such as the polymer constituting the adhesive.

In addition to the above, examples of the adhesive include active energy ray-curable adhesives such as an ultraviolet curable adhesive and an electron beam curable adhesive. Examples of the active energy ray-curable adhesive include (meth) acrylate-based adhesives. Examples of the curable component in the (meth) acrylate-based adhesive include a compound having a (meth) acryloyl group and a compound having a vinyl group. Examples of the compound having a (meth) acryloyl group include alkyl (meth) acrylates having 1 to 20 carbon atoms, such as chain alkyl (meth) acrylates, alicyclic alkyl (meth) acrylates, and polycyclic alkyl (meth) acrylates. ) Acrylate; hydroxyl group-containing (meth) acrylate; epoxy group-containing (meth) acrylate such as glycidyl (meth) acrylate can be mentioned. The (meth) acrylate-based adhesives are hydroxyethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, (meth) acrylamide, and (meth). It may contain a nitrogen-containing monomer such as acrylamide. The (meth) acrylate-based adhesive contains tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecanedimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO as cross-linking components. It may contain a polyfunctional monomer such as modified diglycerin tetraacrylate. Further, a compound having an epoxy group or an oxetanyl group can also be used as the cationic polymerization curable adhesive. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used.

The adhesive may contain an appropriate additive, if necessary. Examples of the additive include a silane coupling agent, a coupling agent such as a titanium coupling agent, an adhesion promoter such as ethylene oxide, an ultraviolet absorber, a deterioration inhibitor, a dye, a processing aid, an ion trap agent, and an antioxidant. Examples thereof include agents, tackifiers, fillers, plasticizers, leveling agents, foaming inhibitors, antistatic agents, heat-resistant stabilizers, and hydrolysis-resistant stabilizers.

The adhesive may be applied to either the transparent protective film side (or the functional layer side described later) or the polarizing film side, which will be described later, or both. After bonding, a drying step is performed to form an adhesive layer composed of a coating and drying layer. After the drying step, ultraviolet rays or electron beams can be irradiated if necessary. The thickness of the adhesive layer is not particularly limited, and when an aqueous adhesive or the like is used, it is preferably about 30 to 5000 nm, more preferably about 100 to 1000 nm, and an ultraviolet curable adhesive. When an electron beam-curable adhesive or the like is used, it is preferably about 0.1 to 100 μm, and more preferably about 0.5 to 10 μm.

When the pressure-sensitive adhesive layer or the adhesive layer contains the hindered amine compound, the content of the hindered amine compound is a pressure-sensitive adhesive from the viewpoint of suppressing a decrease in single transmittance due to coloring of the polarizing film in a high temperature environment. In the layer or the adhesive layer, it is preferably 1% by weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, and preferably 70% by weight or less. , 50% by weight or less is more preferable.

<Single-sided protective polarizing film and double-sided protective polarizing film>
In the single-sided protective polarizing film of the present invention, a transparent protective film is attached to at least one surface of the polarizing film via the adhesive layer or the adhesive layer. Further, in the double-sided protective polarizing film of the present invention, a transparent protective film is bonded to both sides of the polarizing film via the adhesive layer or the adhesive layer.

The transparent protective film is not particularly limited, and various transparent protective films used for the polarizing film can be used. As the material constituting the transparent protective film, for example, a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property, etc. is used. Examples of the thermoplastic resin include cell roll ester resins such as triacetyl cell rolls, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone resins, polysulfone resins, polycarbonate resins, nylon and fragrances. Polyamide resin such as group polyamide, polyimide resin, polyethylene, polypropylene, polyolefin resin such as ethylene / propylene copolymer, (meth) acrylic resin, cyclic polyolefin resin having cyclo or norbornene structure (norbornene resin) ), Polyallylate-based resin, polystyrene-based resin, polyvinyl alcohol-based resin, and mixtures thereof. Further, as the transparent protective film, a cured layer formed of a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, silicone or the like or an ultraviolet curable resin can be used. Among these, cell roll ester-based resins, polycarbonate-based resins, (meth) acrylic-based resins, cyclic polyolefin-based resins, and polyester-based resins are preferable.

The thickness of the transparent protective film can be appropriately determined, but in general, it is preferably about 1 to 500 μm, preferably about 1 to 300 μm, from the viewpoint of workability such as strength and handleability, and thin layer property. More preferably, it is more preferably about 5 to 100 μm.

In the transparent protective film, the hindered amine compound moves (retains) inside the image display device together with the water content inside the image display device (moisture existing in the adhesive layer, the adhesive layer, etc.), and the polarizing film is formed. from the viewpoint of easy Shimiiri, preferably moisture permeability is 50g ^{/ (m} 2 · 24h or more, more preferably 100g ^/ (m 2 · 24h) or more, at 200g ^/ (m 2 · 24h) or higher The moisture permeability is more preferably 40 ° C. according to the moisture permeability test (cup method) of JIS Z0208, a sample cut to a diameter of 60 mm is set in a moisture permeability cup containing about 15 g of calcium chloride. It can be calculated by measuring the weight increase of calcium chloride before and after being placed in a thermostat having a humidity of 90% RH and left for 24 hours.

When the transparent protective film is attached to both sides of the polarizing film, the transparent protective films on both sides may be the same or different.

As the transparent protective film, a retardation plate having a front retardation of 40 nm or more and / or a thickness direction retardation of 80 nm or more can be used. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retardation plate is used as the transparent protective film, the retardation plate also functions as a transparent protective film, so that the thickness can be reduced.

Examples of the retardation plate include a birefringent film formed by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a film in which an alignment layer of a liquid crystal polymer is supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm. The phase plate may be attached to a transparent protective film having no phase difference.

The transparent protective film contains any suitable additives such as UV absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, antistatic agents, pigments, colorants and the like. You may. In particular, when the transparent protective film contains an ultraviolet absorber, the light resistance of the polarizing film can be improved.

A functional layer such as a hard coat layer, an antireflection layer, a sticking prevention layer, a diffusion layer or an antiglare layer can be provided on the surface of the transparent protective film to which the polarizing film is not bonded. The functional layers such as the hard coat layer, the antireflection layer, the sticking prevention layer, the diffusion layer and the antiglare layer can be provided on the protective film itself, or may be separately provided separately from the protective film. it can.

The polarizing film and the transparent protective film, or the polarizing film and the functional layer are usually bonded via the pressure-sensitive adhesive layer or the adhesive layer.

The transparent protective film and the polarizing film, or the polarizing film and the functional layer may be laminated via an intervening layer such as a surface modification treatment layer, an easy-adhesive layer, a block layer, or a refractive index adjusting layer. ..

Examples of the surface modification treatment for forming the surface modification layer include corona treatment, plasma treatment, primer treatment, and saponification treatment.

Examples of the easy-adhesive agent for forming the easy-adhesive layer include a forming material containing various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. Can be mentioned. The easy-adhesive layer is usually provided in advance on a protective film, and the easy-adhesive layer side of the protective film and the polarizing film are laminated by the adhesive layer or the adhesive layer.

The block layer is a layer having a function for preventing impurities such as oligomers and ions eluted from the transparent protective film and the like from migrating (invading) into the polarizing film. The block layer may be a layer having transparency and capable of preventing impurities eluted from the transparent protective film or the like, and examples of the material forming the block layer include urethane prepolymer-based forming materials and cyanoacrylates. Examples include system-forming materials and epoxy-based forming materials.

The refractive index adjusting layer is a layer provided for suppressing a decrease in transmittance due to reflection between layers having different refractive indexes such as the transparent protective film and a polarizing film. Examples of the refractive index adjusting material for forming the refractive index adjusting layer include forming agents containing various resins having silica-based, acrylic-based, acrylic-styrene-based, melamine-based, and the like, and additives.

The polarizing film of the present invention has a general formula (1): X (% by weight)> 0.01 (in the general formula (1), from the viewpoint of suppressing a decrease in the single transmittance due to coloring of the polarizing film in a high temperature environment. X is a laminate in which a glass plate is bonded to both sides of a polarizing film in which a transparent protective film is bonded to at least one side of the polarizing film via the adhesive layer at 105 ° C. The content of the hindered amine-based compound in the polarizing film in the laminate left under the condition of 24 hours is shown.). The X (% by weight) is preferably 0.02 or more, and more preferably 0.05 or more.

<Laminated polarizing film>
In the laminated polarizing film (optical laminate) of the present invention, an optical layer is bonded to at least one surface of the single-sided protective polarizing film or the double-sided protective polarizing film via the adhesive layer or the adhesive layer. Is what you have.

The optical layer is not particularly limited, but is used for forming, for example, a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a liquid crystal display device such as a viewing angle compensation film, or the like. One or two or more optical layers that may be used can be used. The laminated polarizing film is particularly a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on the polarizing film, and a retardation plate is further laminated on the polarizing film. Examples thereof include an elliptically polarizing film or a circularly polarizing film, a wide viewing angle polarizing film in which a viewing angle compensating film is further laminated on the polarizing film, and a polarizing film in which a brightness improving film is further laminated on the polarizing film.

On one or both sides of the single-sided protective polarizing film, the double-sided protective polarizing film, or the laminated polarizing film, an image display cell such as a liquid crystal cell or an organic EL element, and a front transparent plate or a touch panel on the visual side The adhesive layer or the adhesive layer may be attached in advance in order to attach other members such as the front transparent member. In this way, a polarizing film or a laminated polarizing film having an adhesive layer provided on at least one surface thereof is a single-sided protective polarizing film with an adhesive layer, a double-sided protective polarizing film with an adhesive layer, or an adhesive layer. It is called a laminated polarizing film with.

It is preferable that the pressure-sensitive adhesive layer or 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. As a result, contamination of the pressure-sensitive adhesive layer or the adhesive layer can be prevented under normal handling conditions. As the separator, for example, an appropriate thin leaf such as a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a net, a foam sheet or a metal foil, or a laminate thereof, and if necessary, a silicone-based or long-chain alkyl-based separator. Those coated with an appropriate release agent such as fluorine-based or molybdenum sulfide are used.

<Front transparent member>
The front transparent member of the present invention is a front transparent member arranged on the visual side of the image display cell. Examples of the front transparent member include a front transparent plate (window layer) and a touch panel. As the front transparent plate, a front transparent plate having appropriate mechanical strength and thickness is used. As such a transparent plate, for example, a transparent resin plate such as an acrylic resin or a polycarbonate resin, a glass plate, or the like is used. As the touch panel, for example, various touch panels such as a resistive film method, a capacitance method, an optical method, an ultrasonic method, and a glass plate or a transparent resin plate having a touch sensor function are used. When a capacitance type touch panel is used as the front transparent member, it is preferable to provide a front transparent plate made of glass or a transparent resin plate on the visual side of the touch panel.

<Image display cell>
Examples of the image display cell of the present invention include a liquid crystal cell and an organic EL cell. Examples of the liquid crystal cell include a reflective liquid crystal cell that uses external light, a transmissive liquid crystal cell that uses light from a light source such as a backlight, and a semitransmissive liquid cell that uses both external light and light from a light source. Any of the semi-reflective liquid crystal cells may be used. When the liquid crystal cell uses light from a light source, in the image display device (liquid crystal display device), a polarizing film is also arranged on the side opposite to the viewing side of the image display cell (liquid crystal cell), and the light source is further arranged. Be placed. It is preferable that the polarizing film on the light source side and the liquid crystal cell are bonded to each other via an appropriate adhesive layer. As the driving method of the liquid crystal cell, for example, any type such as VA mode, IPS mode, TN mode, STN mode and bend orientation (π type) can be used.

As the organic EL cell, for example, a cell in which a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitting body (organic electroluminescence light emitting body) is preferably used. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, or these. Various layer configurations can be adopted, such as a laminate of an electron injection layer composed of the light emitting layer and a perylene derivative, or a laminate of a hole injection layer, a light emitting layer, and an electron injection layer.

The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

<Example 1>
<Preparation of polarizing film>
A polyvinyl alcohol film having an average degree of polymerization of 2,400, a saponification degree of 99.9 mol%, and a thickness of 45 μm was prepared. The polyvinyl alcohol film was immersed in a swelling bath (water bath) at 20 ° C. for 30 seconds between rolls having different peripheral speed ratios and stretched 2.2 times in the transport direction while swelling (swelling step). The iodine concentration of the polarizing film finally obtained in a dyeing bath at 30 ° C. (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1: 7 with respect to 100 parts by weight of water) is 4. While adjusting the concentration to .47% by weight, immersing and dyeing for 30 seconds, 3.3 times in the transport direction with reference to the original polyvinyl alcohol film (polyvinyl alcohol film not stretched at all in the transport direction). Stretched to (dyeing step). Next, the dyed polyvinyl alcohol film is immersed in a cross-linked bath at 40 ° C. (an aqueous solution having a boric acid concentration of 3.0% by weight and a potassium iodide concentration of 3.0% by weight) for 28 seconds to obtain the original polyvinyl alcohol. The film was stretched up to 3.6 times in the transport direction with reference to the film (crosslinking step). Further, the obtained polyvinyl alcohol film is immersed in a stretching bath at 61 ° C. (an aqueous solution having a boric acid concentration of 4.0% by weight and a potassium iodide concentration of 5.0% by weight) for 60 seconds to obtain the original polyvinyl alcohol. After stretching up to 6.0 times in the transport direction with reference to the alcohol film (stretching step), a washing bath at 35 ° C. (potassium iodide concentration 2.0% by weight, hindered amine system represented by the following general formula (6)) It was immersed in an aqueous solution having a compound concentration of 0.4% by weight for 10 seconds (washing step). The washed polyvinyl alcohol film was dried at 40 ° C. for 30 seconds to prepare a polarizing film. The hindered amine content in the polarizing film determined by the following measuring method was 0.28% by weight, and the thickness of the polarizing film was 18 μm. The hindered amine compound represented by the following general formula (6) is a compound that dissolves in an amount of 1 part by weight or more with respect to 100 parts by weight of water at 25 ° C.

[Method for measuring the content (% by weight) of hindered amine compounds in the polarizing film]
Approximately 20 mg of the polarizing film is collected, quantified, heated and dissolved in 1 mL of water, diluted with 4.5 mL of methanol, the obtained extract is filtered through a membrane filter, and the filtrate is HPLC (ACQUITY UPLC manufactured by Waters). The concentration of the hindered amine compound was measured using H-class Bio).

[Measuring method of iodine content (% by weight) in polarizing film]
The iodine concentration (% by weight) of the polarizing film was determined using the following formula using a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, trade name "ZSX-PRIMUS IV", measurement diameter: ψ20 mm).
Iodine concentration (wt%) = 14.474 × (X-ray fluorescence intensity) / (Film thickness) (kcps / μm) The coefficient for calculating the concentration differs depending on the measuring device, but the coefficient is an appropriate calibration curve. Can be obtained using.

<Manufacturing of polarizing film>
As an adhesive, a polyvinyl alcohol resin containing an acetoacetyl group (average degree of polymerization of 1,200, saponification degree of 98.5 mol%, acetoacetylation degree of 5 mol%) and methylol melamine in a weight ratio of 3: The aqueous solution contained in 1 was used. Using this adhesive, to both sides of the polarizing film obtained above, a transparent protective film, triacetyl cellulose film 47μm thick with a hard coat layer (moisture permeability ^{342g / (m 2 · 24h)} , Konica Minolta (Manufactured by, trade name "KC4UYW") is bonded with a roll bonding machine, and then heat-dried in an oven (temperature is 60 ° C., time is 4 minutes), and transparent protective films are bonded to both sides of the polarizing film. The polarizing film was produced. The simple substance transmittance of the polarizing film was 37.4%.

<Preparation of acrylic adhesive>
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler was charged with a monomer mixture containing 99 parts by weight of butyl acrylate and 1 part by weight of 4-hydroxybutyl acrylate. Further, with respect to 100 parts by weight of the monomer mixture (solid content), 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator is charged together with 100 parts by weight of ethyl acetate, and the mixture is gently stirred. After introducing nitrogen gas and substituting with nitrogen, the liquid temperature in the flask was maintained at around 55 ° C. and a polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.8 million. Then, with respect to 100 parts by weight of the solid content of the obtained acrylic polymer solution, 0.02 part by weight of an isocyanate cross-linking agent (manufactured by Tosoh Corporation, trade name "Takenate D110N", trimethylolpropane / xylylene diisocyanate adduct) , 0.2 part by weight of a silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "X-41-1056") was blended to prepare a solution of an acrylic pressure-sensitive adhesive composition. Next, the solution of the acrylic pressure-sensitive adhesive composition obtained above was dried on one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film, trade name "MRF38", separator film) treated with a silicone-based release agent. The pressure-sensitive adhesive layer was applied so as to have a thickness of 20 μm, and dried at 90 ° C. for 1 minute to form a pressure-sensitive adhesive layer on the surface of the separator film. Next, the pressure-sensitive adhesive layer formed on the separator film was transferred to one surface of the polarizing film produced above to prepare a polarizing film with a pressure-sensitive adhesive layer.

<Manufacturing of pseudo image display device (laminated body)>
The polarizing film with an adhesive layer obtained above is cut into a size of 40 × 40 mm so that the absorption axis of the polarizing film is the long side, and a glass plate (pseudo image display cell) is attached via the adhesive layer. At the same time, another glass plate (pseudo front transparent member) is attached to the other surface of the polarizing film via a 200 μm-thick acrylic acid monomer-free adhesive (manufactured by Nitto Denko Co., Ltd., trade name “LUCICAS CS9868”). , A pseudo image display device (laminated body) was produced.

[Evaluation of single transmittance in high temperature environment]
The pseudo image display device (laminated body) obtained above was allowed to stand in a hot air oven at a temperature of 105 ° C. for 48 hours, and the single transmittance (ΔTs) before and after charging (heating) was measured. The single transmittance was measured using a spectrophotometer (manufactured by Murakami Color Technology Laboratory Co., Ltd., product name "DOT-3") and evaluated according to the following criteria. The single transmittance is a Y value obtained by correcting the luminosity factor with a 2 degree field of view (C light source) of JlS Z 8701-1982. The measurement wavelength is 380 to 700 nm (every 10 nm). The results are shown in Table 1.
ΔTs (%) = Ts ₄₈ −Ts ₀
Here, Ts ₀ is the single transmittance of the pseudo image display device (laminated body) before heating, and Ts ₄₈ is the single transmittance of the pseudo image display device (laminated body) after heating for 48 hours.
◯: 5 ≧ ΔTs (%) ≧ 0
X: ΔTs (%)> 5, or ΔTs (%) <0

The ΔTs (%) is preferably 5 ≧ ΔTs (%) ≧ 0, and more preferably 4 ≧ ΔTs (%) ≧ 0.

[Measurement of the content of hindered amine compounds contained in the polarizing film in a high temperature environment]
The pseudo image display device (laminate) obtained above was allowed to stand in a hot air oven at a temperature of 105 ° C. for 24 hours, and the content of the hindered amine compound contained in the polarizing film after charging (heating) was as follows. Obtained by the method. When the simulated image display device after heating was immersed in a solution of about 1000 mL of methylene chloride or toluene for 3 days or more and the protective film was dissolved to take out the polarizing film, the polarizing film was about 40 mg. After washing the polarizing film with pure methylene chloride or toluene, about 1 mg of the polarizing film is collected, quantified, heated and dissolved in 0.5 mL of water, diluted with 1 mL of methanol, and the obtained extract is used as a membrane. The filtrate was filtered through a filter, and the concentration of the hindered amine compound was measured using LCMS (Ultimate 3000 / LTQ orbitrap XL manufactured by Thermo Fisher Scientific).

<Example 2>
<Manufacturing of polarizing film, optical film, pseudo image display device (laminated body)>
In the preparation of the polarizing film, the hindered amine-based compound represented by the general formula (6) is not added to the washing bath, and both adhesives used in the preparation of the polarizing film are the hindered amine-based compounds represented by the general formula (6). A polarizing film, a polarizing film, and a pseudo image display device (laminate) were produced by the same operation as in Example 1 except that the compound was added so as to have a weight ratio of 4: 3 with the polyvinyl alcohol resin. did. The simple substance transmittance of the polarizing film was 39.7%.

<Example 3>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
In the preparation of the polarizing film, the hindered amine-based compound represented by the general formula (6) is not added to the washing bath, and in the preparation of the polarizing film, the hindered amine-based compound represented by the general formula (7) is used for both adhesives. The compound was added so as to have a weight ratio of 4: 3 with the polyvinyl alcohol resin, and water had a molar ratio of 1: 1 with respect to the hindered amine compound so as not to affect the curing reaction of the adhesive. A polarizing film, a polarizing film, and a pseudo-image display device (laminated body) were produced by the same operation as in Example 1 except that potassium oxide was added to adjust the pH (neutralized). The simple substance transmittance of the polarizing film was 40.0%. The hindered amine compound represented by the following general formula (7) is a compound that dissolves in an amount of 1 part by weight or more with respect to 100 parts by weight of water at 25 ° C.

<Example 4>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
In the preparation of the polarizing film, the hindered amine-based compound represented by the general formula (6) is not added to the washing bath, and in the preparation of the polarizing film, the hindered amine-based compound represented by the general formula (8) is used for both adhesives. The compound was added so as to have a weight ratio of 4: 3 with the polyvinyl alcohol resin, and hydrochloric acid was added so as to have a molar ratio of 1: 1 with respect to the hindered amine compound so as not to affect the curing reaction of the adhesive. A polarizing film, a polarizing film, and a pseudo-image display device (laminate) were produced by the same operations as in Example 1 except that the pH was adjusted (neutralized) by adding .. The simple substance transmittance of the polarizing film was 39.9%. The hindered amine compound represented by the following general formula (8) is a compound that dissolves in an amount of 1 part by weight or more with respect to 100 parts by weight of water at 25 ° C.

<Example 5>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
A polyvinyl alcohol resin containing an acetoacetyl group as both adhesives used in the production of the polarizing film without adding the hindered amine compound represented by the general formula (6) to the washing bath in the production of the polarizing film. The polarizing film and the polarizing film were carried out in the same manner as in Example 1 except that an aqueous solution containing methylol melamine and a hindered amine compound represented by the general formula (6) in a weight ratio of 7: 2: 1 was used. , And a pseudo image display device (laminated body) was produced. The simple substance transmittance of the polarizing film was 39.7%.

<Example 6>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of the photoinitiator "IRGACURE 819" (manufactured by BASF) as both adhesives used in the production of polarizing films. To prepare an adhesive, apply it on a polarizing film so that the thickness of the adhesive layer after curing is 1.0 μm, irradiate ultraviolet rays as active energy rays, and cure the adhesive to make the polarizing film. A polarizing film, a polarizing film, and a pseudo-image display device (laminated body) were produced by the same operation as in Example 1 except that the above was produced. For ultraviolet irradiation, gallium-filled metal halide lamp, irradiation device: Fusion UV Systems, Light HAMMER10 manufactured by Inc., valve: V valve, peak illuminance: 1600 mW / cm ² , cumulative irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm). ), And the illuminance of ultraviolet rays was measured using a Solar-Check system manufactured by Solartell.

<Example 7>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
As the thermoplastic resin base material, an amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a long shape, a water absorption rate of 0.75%, and a Tg of about 75 ° C. was used. One side of the resin base material was corona-treated. 100 weight of PVA-based resin in which polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetacetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z410") are mixed at a ratio of 9: 1. 13 parts by weight of potassium iodide was added to the part to prepare a PVA aqueous solution (coating liquid). The PVA aqueous solution was applied to the corona-treated surface of the resin base material and dried at 60 ° C. to form a PVA-based resin layer having a thickness of 13 μm to prepare a laminate. The obtained laminate was uniaxially stretched at the free end 2.4 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130 ° C. (aerial auxiliary stretching treatment). Next, the laminate was immersed in an insolubilizing bath (an aqueous solution having a boric acid concentration of 4.0% by weight) at a liquid temperature of 40 ° C. for 30 seconds (insolubilization treatment). Next, the finally obtained polarizing film is placed in a dyeing bath having a liquid temperature of 30 ° C. (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1: 7 with respect to 100 parts by weight of water). It was immersed for 60 seconds while adjusting the concentration so that the iodine concentration was 8.11% (dyeing treatment). Then, it was immersed in a cross-linking bath (an aqueous solution having a potassium iodide concentration of 3.0% by weight and a boric acid concentration of 5.0% by weight) at a liquid temperature of 40 ° C. for 30 seconds (cross-linking treatment). Then, while immersing the laminate in a boric acid aqueous solution (boric acid concentration 4.0% by weight) at a liquid temperature of 70 ° C., the total draw ratio is 5.5 in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds. Uniaxial stretching was performed so as to double (underwater stretching treatment). Then, the laminate was immersed in a washing bath (potassium iodide concentration 3% by weight) at a liquid temperature of 30 ° C. (washing treatment). Then, while drying in an oven kept at 90 ° C., it was brought into contact with a heating roll made of SUS whose surface temperature was kept at 75 ° C. for about 2 seconds (dry shrinkage treatment). In this way, a polarizing film having a thickness of 5 μm was formed on the resin base material.

Then, as an adhesive, a polyvinyl alcohol resin containing an acetoacetyl group (average degree of polymerization of 1,200, saponification degree of 98.5 mol%, acetoacetylation degree of 5 mol%) and methylol melamine by weight ratio. An aqueous solution containing 3: 1 was used. Using this adhesive, a transparent protection with a thickness of 30 μm made of a (meth) acrylic resin (modified acrylic polymer having a lactone ring structure) on the surface of the polarizing film obtained above opposite to the resin base material. film (manufactured by Nippon Shokubai Co., Ltd., moisture permeability of ^{125g / (m 2 · 24h)} ) were bonded using the bonding roll together machine. Next, the resin base material was peeled off, and an acrylic pressure-sensitive adhesive layer containing a hindered amine compound was transferred to the peeled surface to prepare a polarizing film with a pressure-sensitive adhesive layer. The acrylic pressure-sensitive adhesive containing the hindered amine compound has a general formula (6) of 20 parts by weight as a hindered amine compound with respect to 80 parts by weight of the solid content of the solution of the acrylic polymer, and an isocyanate cross-linking agent (manufactured by Toso Co., Ltd.). Contains 0.02 parts by weight of the name "Takenate D110N", trimethylolpropane / xylylene diisocyanate adduct, and 0.2 parts by weight of the silane coupling agent (manufactured by Shinetsu Chemical Industry Co., Ltd., trade name "X-41-1056"). Was produced.

The acrylic acid monomer-free pressure-sensitive adhesive described in Example 1 is bonded to the transparent protective film surface of the polarizing film with the pressure-sensitive adhesive layer, and a glass plate is bonded via the pressure-sensitive adhesive layers on both sides to display a pseudo image. (Laminated body) was produced.

<Comparative example 1>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
In the production of the polarizing film, the polarizing film, the polarizing film, and the pseudo image display device were operated in the same manner as in Example 1 except that the hindered amine compound represented by the general formula (6) was not added to the washing bath. (Laminated body) was produced. The obtained polarizing film had a hindered amine content of 0% by weight and a thickness of 18 μm. The simple substance transmittance of the polarizing film was 39.6%.

<Comparative example 2>
<Manufacturing of polarizing film polarizing film and pseudo image display device (laminated body)>
In the production of the polarizing film, the polarizing film, the polarizing film, and the pseudo image display device (laminated body) were produced by the same operation as in Example 7 except that the hindered amine compound was not added to the acrylic pressure-sensitive adhesive. did.

<Comparative example 3>
<Manufacturing of polarizing film, polarizing film, pseudo image display device (laminated body)>
In the preparation of the polarizing film, the hindered amine compound represented by the general formula (6) was not added to the washing bath, and 35 parts by weight of N-hydroxyethyl acrylamide (HEAA) and acryloylmorpholin (ACMO) were used as adhesives. A mixture of 50 parts by weight, 5 parts by weight of the photoinitiator "IRGACURE 819" (manufactured by BASF) and 10 parts by weight of the compound represented by the general formula (9) (trade name "Adecastab LA-52", manufactured by ADEKA). Except for the fact that the adhesive layer after curing was applied onto a polarizing film so that the thickness was 1.0 μm, irradiated with ultraviolet rays as active energy rays, and the adhesive was cured to produce a polarizing film. A polarizing film, a polarizing film, and a pseudo image display device (laminated body) were produced by the same operation as in Example 1. For ultraviolet irradiation, gallium-filled metal halide lamp, irradiation device: Fusion UV Systems, Light HAMMER10 manufactured by Inc., valve: V valve, peak illuminance: 1600 mW / cm ² , cumulative irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm). ), And the illuminance of ultraviolet rays was measured using a Solar-Check system manufactured by Solartell. The hindered amine compound represented by the following general formula (9) is a compound that does not dissolve more than 1 part by weight with respect to 100 parts by weight of water at 25 ° C.

Using the simulated image display devices (laminates) of the examples and comparative examples obtained above, the above-mentioned [evaluation of single transmittance in a high temperature environment] and [hindered amine compounds contained in a polarizing film in a high temperature environment] Content measurement] was performed. The results are shown in Table 1.

10: Polarizing film 11: Polarizing film 12, and 13: Transparent protective film 20, 30, 40, and 50: Adhesive layer or adhesive layer 80: Front transparent member 90: Image display cell 100: Image display device 101: One side Protective polarizing film 102: Double-sided protective polarizing film

Claims (6)

An image display device in which a front transparent member, a polarizing film, and an image display cell are provided in this order via an adhesive layer or an adhesive layer.
The polarizing film has a polarizing film formed by adsorption orientation of iodine on a polyvinyl alcohol-based film.
At least one of the polarizing film, the pressure-sensitive adhesive layer, and the adhesive layer contains a hindered amine compound.
The hindered amine compound is a water-soluble hindered amine compound capable of dissolving 1 part by weight or more in 100 parts by weight of water at 25 ° C.
The polarizing film has a general formula (1): X (% by weight)> 0.01.
(In the general formula (1), in X, a glass plate is attached to both sides of a polarizing film in which a transparent protective film is attached to at least one side of the polarizing film via the adhesive layer. An image display device characterized in that the combined laminate satisfies the condition represented by (indicating the content of the hindered amine compound in the polarizing film) in the laminate left at 105 ° C. for 24 hours. .. The hindered amine compound has a general formula (1):

(In the general formula (1), R ¹ represents an oxy radical, a hydrogen atom, a hydroxy group, or an alkyl group having 1 to 30 carbon atoms, a hydroxyalkyl group, a hydroxyalkoxy group, or an alkoxy group, and is derived from R ^2. R ⁵ is characterized by being a compound having an organic group represented by a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n representing 0 or 1). The image display device according to claim 1. The hindered amine compound has a general formula (2):

(In the general formula (2), R ¹ to R ⁵ and n are the same as above, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an acyl group or an aryl group. , N represents 0 or 1).
General formula (3):

(In the general formula (3), R ¹ to R ⁵ and n are the same as above, and R ⁷ and R ⁸ are independently hydrogen atoms or alkyl groups having 1 to 10 carbon atoms. A compound represented by an acyl group or an aryl group.
General formula (4):

(In the general formula (4), R ¹ to R ⁵ and n are the same as above, and R ⁹ to R ¹¹ are independently hydrogen atoms or alkyl groups having 1 to 10 carbon atoms. A compound represented by an acyl group, an amino group, an alkoxy group, a hydroxy group, or an aryl group), and a general formula (5) :.

(In the general formula (5), R ¹ to R ⁵ and n are the same as above, and R ¹² is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an amino group, an alkoxy group and a hydroxy group. The image display device according to claim 1 or 2, wherein the image display device is one or more compounds selected from the group consisting of compounds represented by (representing a group or an aryl group). The polarizing film is a single-sided protective polarizing film in which a transparent protective film is bonded to at least one surface of the polarizing film via the adhesive layer or the adhesive layer. The image display device according to any one of 3. Any of claims 1 to 3, wherein the polarizing film is a double-sided protective polarizing film in which a transparent protective film is bonded to both sides of the polarizing film via the pressure-sensitive adhesive layer or the adhesive layer. The image display device described in Crab. The claim is a laminated polarizing film in which an optical layer is bonded to at least one surface of the single-sided protective polarizing film or the double-sided protective polarizing film via the adhesive layer or the adhesive layer. The image display device according to 4 or 5.

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