TW201513954A - A method of making polarizer whose end face is processed - Google Patents

Abstract

This application provides a method of making polarizer whose end face is processed, the method comprising: a step of stacking a plurality of square polarizers to obtain a polarizer laminate which exposes an end face, the square polarizer having (meth)acrylic resin film on a polarizing film; a step of cutting the end face by moving a cutting tool having n pieces of cutting blades relative to the polarizer laminate; whereby the end face is cut by the cutting tool so that the following conditions are satisfied: (a) the number of times that the n pieces of cutting blades abuts the end face is 200 to 1500 times per 100 mm of length on the length direction of the end face; (b) a cutting depth by one relative movement is 0.3mm or less.

Description

Method for manufacturing end face processing polarizing plate

The present invention relates to a method of manufacturing a face-finished polarizing plate.

A polarizing plate is widely used as a constituent member of a liquid crystal display device. As the polarizing plate, a protective film is generally laminated on at least one surface of a polarizing film containing a polyvinyl alcohol-based resin, and a triethylenesulfonated cellulose film is conventionally used for the protective film. However, trimethyl fluorenyl cellulose has insufficient heat and humidity resistance, and a polarizing plate of a protective film using a triethylene fluorenyl cellulose film may have a lower degree of polarization and color under high temperature conditions and under moist heat conditions.

For this reason, a (meth)acrylic resin film which is excellent in transparency and moist heat resistance has been proposed as a protective film for the triacetyl-based cellulose film (for example, Japanese Laid-Open Patent Publication No. 2010-231015).

On the other hand, when a polarizing plate is applied to a liquid crystal display device, it is usually bonded to a liquid crystal cell, for example, after being cut into a predetermined shape such as a rectangular shape and a predetermined size, and then bonded to a liquid crystal cell. Further, the polarizing plate bonded to the liquid crystal cell is expected to have a smooth end surface even if it is an end surface which is formed by cutting. Therefore, the cut polarizing plate usually makes the size match the liquid crystal The cell is used as an end face processed polarizer which has been processed into a smooth end face.

The method of processing the end surface of the polarizing plate is disclosed, for example, in Japanese Laid-Open Patent Publication No. 2012-203209, JP-A-2012-203210, and JP-A-2007-223021. In the polarizing plate in which the extended polyethylene terephthalate film is used as a protective film, a plurality of polarizing plates in which the polarizing plates are stacked are disclosed in Japanese Laid-Open Patent Publication No. 2012-203209 and No. 2012-203210. The method of manufacturing the end face processing polarizing plate in which the end face of the laminated body is cut without causing peeling of the stretched polyethylene terephthalate film and the end surface after cutting is in a good state.

Japanese Patent Publication No. 2007-223021 discloses a cutting member having a cutting insert, and a method of cutting an end surface of a sheet-like member by rotating around a central axis, and cutting is performed for the purpose of completing a good end surface. In the cutting region formed by the blade, the region away from the central axis contacts the end face. However, in this method, in the cutting region, the cutting process is performed in a very small area away from the central axis, and the end face of the polarizing plate laminated body in which the plurality of polarizing plates are stacked is subjected to the cutting process, and the height of the polarizing plate laminated body is affected. Restriction, in the state where more polarizing plates are stacked, processing cannot be integrated, and processing efficiency is poor.

The (meth)acrylic resin film as the protective film has the above-described advantages, and the polarizing plate is used, and the (meth)acrylic resin film and the polarizing film tend to be easily peeled off even with a small impact. .

Therefore, an object of the present invention is to provide a method for producing an end face-processed polarizing plate by cutting an end surface of a polarizing plate using a (meth)acrylic resin film as a protective film, wherein a (meth)acrylic acid can be produced without accompanying In the end surface processing of the peeling of the resin film, even after the end surface processing, the impact resistance of the end surface is suppressed from being lowered, and the end surface-processed polarizing plate which is less likely to cause peeling of the (meth)acrylic resin film can be produced with good workability. method.

The present invention provides a method of producing a face-cut polarizing plate shown below.

[1] A method of producing a face-finished polarizing plate, comprising: stacking a plurality of sheets comprising a polarizing film comprising a polyvinyl alcohol-based resin; and a prismatic polarizing plate comprising a (meth)acrylic resin film laminated thereon with an adhesive, The first step of obtaining the polarizing plate laminate having the exposed end faces, and the longitudinal direction of the end face, the cutting tool is relatively moved by the polarizing plate laminate, and the end faces are cut and processed to obtain the end face processing polarizing plate. The second step; wherein the cutting tool has n pieces parallel to the end surface and rotating in a direction substantially perpendicular to a longitudinal direction of the end surface, and rotating in a direction extending from the rotation axis (here n In the second step, the end surface satisfies the following condition, and the cutting tool is rotated by the cutting tool that rotates around the rotating shaft: (a) the n-cutting The number of times the blade abuts the aforementioned end face, facing the front The length per 100 mm in the longitudinal direction of the end surface is 200 or more and 1,500 or less; and (b) the depth of cut in the depth direction of the end surface cut by the relative movement of one time is 0.3 mm or less.

[2] The method according to [1], wherein the relative movement is performed from one end to the other end in the longitudinal direction of the end surface, and the relative movement from the one end to the other end is one time, and the end surface is subjected to the plurality of times .

[3] The method according to [2], wherein in the second step, the cutting is performed so that the total depth of cut in the depth direction is 0.2 mm or more and 1.5 mm or less.

[4] The method according to [2], wherein, in the second step, the total depth of cut in the depth direction of the end surface cut by the last relative movement in the plurality of relative movements of the end surface The cutting process is performed so as to be 0.01 mm or more and 0.1 mm or less.

The method according to any one of the above [1], wherein, in the second step, the polarizing plate laminate is used for one of the polarizing plate laminates, and the two polarizing plate laminates are used. Simultaneous cutting machining with respect to 2 end faces.

[6] The method according to any one of [1] to [5] wherein the relative movement is performed by moving the polarizing plate laminate while the position of the cutting tool is fixed.

The method according to any one of the above aspects, wherein the polarizing plate includes the (meth)acrylic resin film laminated on the surface of one side of the polarizing film via an adhesive. And the adhesive on the other side is separated by an adhesive Other transparent resin films laminated.

[8] The method according to [7], wherein the other transparent resin film is composed of a cyclic olefin resin.

[9] The method according to [7], wherein the polarizing plate further comprises: an adhesive layer laminated on the outer surface of the other transparent resin film; and a release film laminated on the outer surface of the adhesive layer; And a surface protective film laminated on the outer surface of the (meth)acrylic resin film.

According to the present invention, the (meth)acrylic resin film is used for the protective film, but the peeling of the protective film and the polarizing film can be suppressed, and the end face processed polarizing plate can be produced with good workability. Further, it is possible to suppress a decrease in impact resistance of the end surface of the obtained end face-processed polarizing plate, and it is not easy to cause peeling of the (meth)acrylic resin film.

10, 11‧‧‧ cutting tools

10a, 11a‧‧‧ cutting inserts

20‧‧‧Upper press

21‧‧‧ Lower press

30‧‧‧Brazil

31‧‧‧Rotating table

41, 42, 43, 44‧‧‧ end faces

W‧‧‧Polarized plate laminate

Fig. 1 is a perspective view showing an example of a second step of cutting the end face of the polarizing plate laminate of the present invention and an end face processing device used in the step.

Fig. 2(a) and Fig. 2(b) are schematic plan views showing an example of a second step of cutting the end face of the polarizing plate laminate of the present invention.

Fig. 3 is a schematic plan view showing another example of the second step of cutting the end surface of the polarizing plate laminate of the present invention.

<Method of Manufacturing End Face Processing Polarizing Plate>

The method for producing a face-finished polarizing plate of the present invention includes the steps of: [a] stacking a plurality of square polarizing plates using a (meth)acrylic resin film as a protective film, and obtaining the first polarizing plate laminate. Step; and [b] cutting the polarizing plate laminate by relatively moving the polarizing plate laminate body along the longitudinal direction of the end surface of the obtained polarizing plate laminate by rotating the cutting tool having the cutting insert centered on the rotating shaft The second step of the end face of the body. The steps are described in detail below.

[Step 1]

This step is a step of stacking a plurality of square polarizing plates to obtain a polarizing plate laminate. The term "square" means a square or a rectangle, and the size thereof is not particularly limited. The number of the stacked polarizing plates is not particularly limited. According to the present invention, even in the case where the polarizing plate laminate has a considerable height, the end faces of the polarizing plates can be collectively processed in a good completion state, and the processing efficiency is good.

The polarizing plate used in the present invention is provided with at least a polarizing film comprising a polyvinyl alcohol-based resin and a polarizing plate of a (meth)acrylic resin film laminated thereon with an adhesive. A more detailed configuration of the polarizing plate will be described later. The polarizing plate used in the present invention is usually obtained by cutting a long polarizing plate.

Referring to FIG. 1 which is a second step of the description of the end face of the laminate for processing the polarizing plate laminate, the polarizing plate laminate W obtained by stacking a plurality of polarizing plates has four exposed end faces, each of which is composed of a stack. The exposed end faces of the stacked polarizing plates are formed. A plurality of polarizing plates are stacked in such a 4-sided alignment. Stacking of polarizers can be done automatically or manually.

[Step 2]

In this step, the end face of the polarizing plate laminate obtained in the first step is subjected to a cutting process by a cutting tool to obtain a step of processing the polarizing plate on the end surface. Fig. 1 is a perspective view showing an example of a second step of cutting the end face of the polarizing plate laminate of the present invention and an end face processing device used in the step.

Referring to Fig. 1, first, an end face processing apparatus used for cutting a face of a polarizing plate laminate body will be described. For example, as shown in Fig. 1, the end surface processing apparatus may be configured to press the polarizing plate laminate W from above and below, and to fix the polarizing plate laminate W itself without moving and the stacked polarizing plates are not offset during the cutting process. a pressing device 20 and a lower pressing device 21; a rotating table 31 that supports the lower pressing device 21 and is rotatable about a central axis parallel to the lamination direction z of the polarizing plate; and is attached to the upper pressing device 20 and The rotary table 31 is synchronized with the presser 30 that rotates in the same direction, and two cutting tools (cutting rotary bodies) 10 and 11 for cutting the end faces of the polarizing plate laminate W are cut.

As shown in Fig. 1, the cutting tools 10 and 11 are end faces of the parallel polarizing plate laminate W, and are rotatable by a rotation axis that is approximately perpendicular to the longitudinal direction of the end surface. The shape may be, for example, a cylindrical shape. The term "longitudinal direction of the end face" means the direction of the lamination direction z of the vertical polarizing plate. The so-called "about vertical" means cutting The angle α between the rotation axis of the cutting tools 10 and 11 and the lamination direction z of the polarizing plate is 25 degrees or less (including 0 degrees). The diameter of the cylindrical cutting tools 10, 11 is, for example, about 5 to 20 cm.

When the rotation axes of the cutting tools 10 and 11 are inclined to the lamination direction z of the polarizing plate, the adhesion of the adhesive to the cutting inserts 10a and 11a is suppressed from the case where the life of the cutting inserts 10a and 11a is extended or the polarizing plate is provided with the adhesive layer. The point of view is more ideal. However, if the above angle α exceeds 25 degrees, the effective cutting area of the cutting tools 10, 11 is narrowed, and the number of stacked polarizing plates is limited.

Each of the two cutting tools 10 and 11 has n pieces (n is an integer of 1 or more) of the cutting inserts 10a and 11a. The cutting tools 10 and 11 are rotated, and the end faces of the cutting inserts 10a and 11a are abutted against the end faces of the polarizing plate laminate W, and the end faces are cut to perform end surface machining. In the example shown in Fig. 1, the number of the cutting inserts 10a and 11a included in the cutting tools 10 and 11 is four. The cutting inserts 10a and 11a are disposed on the side surface of the rotating body that abuts against the end surface of the polarizing plate laminated body W, and extend in the direction of the rotating shaft of the cutting tools 10 and 11 (for example, parallel to the rotating shaft). The blade lengths of the cutting inserts 10a and 11a are the same as or longer than the height of the polarizing plate laminate W, so that the end faces of all the stacked polarizing plates can be collectively cut. The extending direction of the cutting inserts 10a, 11a can be inclined to the rotation axes of the cutting tools 10, 11.

In the case where the cutting tools 10 and 11 have two or more cutting inserts 10a and 11a, it is preferable that the cutting inserts 10a and 11a are disposed on the side surfaces of the cutting tools 10 and 11 on average.

The reference is equivalent to viewing the first picture from the top (z direction) In the second aspect (a) of the figure of the end face processing shown in the figure, when the end face machining method of this step is described, the polarizing plate laminate W is placed on the lower presser 21 by using the end face processing apparatus as described above. After the upper presser 20 and the lower presser 21 are pressed and fixed from above and below, the two cutting tools 10 and 11 are respectively disposed on the opposite end faces 41 and 42 of the polarizing plate laminate W (of course, the end face 43 may be 44) The outside. Then, after appropriately adjusting the positions of the cutting tools 10 and 11 in the y direction, the cutting tools 10 and 11 are rotated about the rotation axes and along the longitudinal direction of the end faces 41 and 42 of the polarizing plate laminated body W. (Parallel to the longitudinal direction), the cutting tools 10 and 11 are relatively moved by the polarizing plate laminate W, and the cutting inserts 10a and 11a are brought into contact with the end faces 41 and 42 to cut the end faces.

In the example shown in Fig. 1 and Fig. 2(a), the polarizing plate laminate W is horizontally moved in the x direction by using a moving mechanism (not shown) in a state where the cutting tools 10 and 11 are fixed. Thus, the relative movement described above is performed. At this time, the rotation directions of the cutting tools 10 and 11 are generally opposite to the moving direction of the polarizing plate laminate W. That is, referring to Fig. 2(a), the cutting tool 10 is rotated counterclockwise with respect to the traveling direction of the polarizing plate laminate W, and the cutting tool 11 is rotated clockwise. Thereby, the end faces of the respective polarizing plates can be cut to a good finished state.

As shown in FIG. 3, the relative movement may be performed by the cutting tools 10 and 11 horizontally moving in the x direction by using a moving mechanism (not shown) in a state where the polarizing plate laminate W is fixed. In this case, as shown in FIG. 3, while the cutting tool 10 is rotated counterclockwise and the cutting tool 11 is rotated clockwise, the end faces 41 and 42 of the laminated body W are along the polarizing plate. The cutting tools 10, 11 can be moved to the left. However, from the viewpoint of driving control of the end surface processing apparatus, it is preferable to perform cutting processing while fixing the position of the cutting tools 10 and 11 and horizontally moving the polarizing plate laminated body W in the x direction.

In the example shown in Fig. 1 and Fig. 2(a), two cutting tools 10 and 11 are used for one polarizing plate laminated body W, and two opposite end faces 41 of the polarizing plate laminated body W are simultaneously cut and processed. 42, at the point of processing efficiency is extremely advantageous. However, it is also possible to use one cutting tool for one polarizing plate laminate W to be machined.

The relative movement is generally performed from one end to the other end of the end faces 41, 42 of the polarizing plate laminate W, whereby the entire end faces 41, 42 can be cut. When the relative movement from the one end to the other end is one time, the relative movement is performed plural times on the same end surface, that is, the end surface processing is performed in plural times, and the (meth)acrylic resin film and the polarizing film are suppressed. It is a preferable method to peel off and obtain a finished end surface process having a good surface condition or to obtain an end surface process which is less likely to cause peeling of the (meth)acrylic resin film.

The depth of cut in the depth direction of the cut end faces 41 and 42 (the thickness of the cut end face of the polarizing plate) can be easily controlled by adjusting the position of the cutting tools 10 and 11 in the y direction by a moving mechanism (not shown).

After the cutting processing of the end faces 41 and 42 is completed, the end faces of the end faces 43 and 44 (the end faces 41 and 42 in the case where the end faces of the end faces 43 and 44 are processed first) are processed. The end faces of the end faces 43 and 44 can be rotated by the rotary table 31 and the presser 30 to rotate the polarizing plate laminate W by 90 degrees. 2 (b), in the same manner as in the case of the end faces 41 and 42, the cutting tools 10 and 11 are rotated about the rotation axis and along the longitudinal direction of the end faces 43 and 44 of the polarizing plate laminate W ( The parallel direction of the longitudinal direction is performed by relatively moving the cutting tool 10, 11 to the polarizing plate laminate W.

In the present invention, the cutting process of the end faces 41, 42, 43, and 44 of the polarizing plate laminate W is performed in such a manner as to satisfy the following conditions: (a) the number of times the n-piece cutting blades abut against the end faces of the polarizing plate laminate W (the total number of times of the n-cutting inserts, hereinafter also referred to as "the number of times of contact"), and the length per 100 mm in the longitudinal direction of the end surface is 200 or more and 1,500 or less; and (b) the relative movement due to one time The depth of cut in the depth direction of the cut end face (hereinafter referred to as "first-order depth of cut") is 0.3 mm or less.

Regarding the condition (a), the number of times of contact is 200 or more, and it is necessary to obtain a completed end surface having a sufficiently good surface state. In addition, the number of times of the contact is 1,500 or less, and the condition (b) is satisfied, and the peeling of the (meth)acrylic resin film and the polarizing film in the cutting process can be effectively suppressed. In addition, by suppressing the decrease in the impact resistance of the end surface, it is possible to obtain an end face-processed polarizing plate in which the peeling of the (meth)acrylic resin film is less likely to occur and the end surface is in a good state. When the number of times of contact is more than 1,500, the surface of the polarizing plate laminate W may be flawed by the frictional heat between the polarizing plate laminate W and the cutting insert. The number of hits is preferably less than 700 times. The number of abutments can be controlled by adjusting the relative moving speed between the polarizing plate laminate W and the cutting tools 10, 11 and/or the rotational speed of the cutting tools 10, 11.

In the condition (b), the depth of cut is 0.3 mm or less, preferably 0.28 mm or less, and the (meth)acrylic acid in the cutting process can be effectively suppressed while satisfying the above condition (a). Peeling of the resin film and the polarizing film. In addition, by suppressing the decrease in the impact resistance of the end surface, it is possible to obtain an end face processing polarizing plate in which the peeling of the (meth)acrylic resin film is less likely to occur and the end surface is in a good state. In the case where the relative movement is only one time, the cutting depth of one time is preferably 0.2 mm or more. When the depth of cut once is less than 0.2 mm, when the relative movement is only one time, the completed end surface having a sufficiently good surface state may not be obtained.

As described above, the above-described relative movement of the same end faces of the polarizing plate laminate W is preferably performed in a plurality of times. In this case, the total depth of cut (hereinafter also referred to as "total depth of cut") in the depth direction of the end face cut by the plurality of relative movements is preferably 0.2 mm or more and 1.5 mm or less, and more preferably 0.5 mm or more and 1.2 mm or less. ideal. If the total depth of cut is less than 0.2 mm, a completed end surface having a sufficiently good surface state cannot be obtained. Moreover, in the case where the total cutting depth exceeds 1.5 mm, the deterioration of the cutting insert becomes remarkable, and it is possible to simultaneously increase the processing time and the processing efficiency is low. Further, the number of impacts of the end faces of the polarizing plates is excessively increased, and problems such as cracks occur at the ends of the polarizing plates.

The depth of cut once can be controlled by adjusting the position of the cutting tools 10, 11 in the y direction, and the total depth of cut can be controlled by the depth of cut once and the number of relative movements.

In the case where the relative movement is performed plural times, the depth of cut in the depth direction of the end face cut by the last relative movement ( The lower part is also referred to as "cutting depth at completion"), preferably 0.01 mm or more and 0.1 mm or less, more preferably 0.02 mm or more and 0.06 mm or less. In general, it is difficult to perform cutting with an accuracy of less than 0.01 mm. When the depth of cut at the time of completion exceeds 0.1 mm, the impact resistance of the end face may be remarkably lowered in the obtained end face processed polarizing plate.

The relative moving speed between the polarizing plate laminate W and the cutting tools 10 and 11 and the rotational speed of the cutting tools 10 and 11 are adjusted so as to satisfy the above condition (a). The relative movement speed can be selected, for example, from a range of 200 to 2000 mm/min (more typically, a range of 500 to 2000 mm/min). If the relative movement speed is too small, the number of abutments will exceed the above-mentioned upper limit. Further, the frictional heat between the polarizing plate laminate W and the cutting insert may cause a flaw on the end portion of the polarizing plate laminate W. On the other hand, if the relative movement speed is too large, the number of abutments will be lower than the predetermined lower limit described above. Further, the completion processing of the end faces may be insufficient, and a problem such as cracks may occur at the end portions of the polarizing plates.

The rotational speed of the cutting tools 10, 11 can be selected, for example, from 2000 to 8000 rpm (more typically 2500 to 6000 rpm). If the rotation speed is too small, the number of abutments will be lower than the above-mentioned lower limit. Further, the completion processing of the end faces may be insufficient, and a problem such as cracks may occur at the end portions of the polarizing plates. On the other hand, if the rotation speed is too large, the number of abutments will exceed the above-mentioned predetermined upper limit. Further, the frictional heat between the polarizing plate laminate W and the cutting insert may cause a flaw on the end portion of the polarizing plate laminate W.

<Polarizer>

Next, a polarizing plate constituting the polarizing plate laminate W will be described. The polarizing plate used in the present invention is provided with at least a polarizing film containing a polyvinyl alcohol-based resin and a (meth)acrylic resin film laminated thereon with an adhesive.

[Polarizing film]

The polarizing film is not particularly limited, and a step of stretching a polyvinyl alcohol-based resin film through a single axis, a step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye to adsorb a dichroic dye, and adsorbing two colors may be used. A step of treating a polyvinyl alcohol-based resin film of a pigment with a boric acid aqueous solution; and a step of washing with a boric acid aqueous solution and then washing with water.

As the polyvinyl alcohol-based resin film, a polyvinyl acetate-based resin saponifier can be used. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate of a single polymer of vinyl acetate, for example, a copolymer of another monomer copolymerizable with vinyl acetate or the like can be mentioned. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, more preferably 98 mol% or more. The polyvinyl alcohol-based resin can be modified, and for example, an aldehyde-modified polyvinyl formal or polyvinyl acetal can be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 5,000.

A film made of such a polyvinyl alcohol-based resin is used as a raw material film as a polarizing film. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and a conventional method can be employed. The film thickness of the polyvinyl alcohol-based raw material film is, for example, about 10 to 150 μm.

The one-axis extension of the polyvinyl alcohol-based resin can be carried out before dyeing of the dichroic dye, simultaneously with dyeing, or after dyeing. The one-axis extension is carried out after dyeing, and the one-axis extension can be carried out before boric acid treatment or boric acid treatment. Moreover, one-axis extension can also be performed in these plural stages.

When one shaft is extended, one shaft extension can be performed between rollers having different rotation speeds, and one shaft extension can also be performed by using a hot roller. Further, the one-axis extension may be a dry stretching in which the stretching is performed in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is stretched in an expanded state by using a solvent. The stretching ratio is usually about 3 to 8 times.

As a method of dyeing the polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye is used. As the dichroic dye, specifically, iodine or a dichroic dye is used. Further, the polyvinyl alcohol-based resin film is preferably subjected to immersion treatment of water before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is impregnated with an aqueous solution containing iodine and potassium iodide is usually used. The content of iodine in the aqueous solution is usually about 0.01 to 1 part by weight per 100 parts by weight of water. Further, the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually about 20 to 40 °C. Further, the immersion time (dyeing time) of the aqueous solution is usually about 20 to 1800 seconds.

On the other hand, in the case where a dichroic dye is used as the dichroic dye, a method of impregnating a polyvinyl alcohol-based resin film with an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye of the aqueous solution is usually from about 1 × 10 ^-4 to 10 parts by weight, preferably from about 1 × 10 ^-3 to about 1 part by weight, per 100 parts by weight of water. The aqueous solution may also contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous solution used for dyeing is usually about 20 to 80 °C. Further, the immersion time (dyeing time) of the aqueous solution is usually about 10 to 1800 seconds.

The boric acid treatment after dyeing the dichroic dye can be usually carried out by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid.

The amount of boric acid in the aqueous solution containing boric acid is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight, per 100 parts by weight of water. In the case where iodine is used as the dichroic dye, the aqueous solution containing boric acid preferably contains potassium iodide. The amount of potassium iodide in an aqueous solution containing boric acid is usually about 0.1 to 15 parts by weight, preferably about 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time of the aqueous solution containing boric acid is usually about 60 to 1200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50 ° C or higher, preferably 50 to 85 ° C, and more preferably 60 to 80 ° C.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually subjected to a water washing treatment. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of the water to be washed is usually about 5 to 40 °C. Moreover, the immersion time is usually about 1 to 120 seconds.

After washing with water, a drying treatment was carried out to obtain a polarizing film. The thickness of the polarizing film is usually about 5 to 40 μm. Drying treatment can make It is carried out using a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually about 30 to 100 ° C, preferably 50 to 80 ° C. The drying treatment time is usually about 60 to 600 seconds, and preferably 120 to 600 seconds.

By drying treatment, the moisture ratio of the polarizing film is reduced to practical use. The moisture ratio is usually from 5 to 20% by weight, and preferably from 8 to 15% by weight. When the water content is less than 5% by weight, the flexibility of the polarizing film may be lost, and the polarizing film may be damaged or broken after drying. Further, when the water content exceeds 20% by weight, the thermal stability of the polarizing film may be inferior.

[(Meth)acrylic resin film]

The (meth)acrylic resin which is a so-called (meth)acrylic resin film is a material obtained by mixing and kneading a methacrylic resin and an additive which are added as needed. By using such a (meth)acrylic resin film as a protective film, the heat resistance and mechanical strength of the polarizing plate and the liquid crystal panel obtained by bonding the liquid crystal cell to the liquid crystal cell can be further improved, and at the same time, the liquid crystal panel can be further realized. Thin walled. Further, in the present specification, a (meth)acrylic resin is called a methacrylic resin and/or an acrylic resin, a (meth)acrylate is called a methacrylate and/or an acrylate, and a (meth)acrylic acid is called Methacrylic acid and/or acrylic acid.

The above-mentioned methacrylic resin is a polymer mainly composed of methacrylate. The methacrylic resin may be a single polymer of one type of methacrylate, or may be a copolymer of a methacrylate and another polymerizable monomer. Examples of the other polymerizable monomer include other methacrylates and acrylates which are different from the main component. Methyl propyl The enoate ester may, for example, be an alkyl methacrylate such as methyl methacrylate, ethyl methacrylate or butyl methacrylate, and the alkyl group has a carbon number of usually about 1 to 4.

The acrylate is preferably an alkyl acrylate, and examples thereof include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, butylene acrylate, and acrylic acid 2. Ethylhexyl ester, cyclohexyl acrylate or the like has an alkyl group having a carbon number of usually from 1 to 8, more preferably from 1 to 4. The alkyl group, for example, a 2-hydroxyethyl group, at least one hydrogen atom thereof may be substituted with a hydroxyl group. As the (meth)acrylic resin, one type or two or more types of acrylates may be used in combination.

Further, a compound having at least one polymerizable carbon-carbon double bond in the molecule may be another polymerizable monomer copolymerizable with the methacrylate. As such a compound, for example, a monofunctional monomer having one polymerizable carbon-carbon double bond in the molecule and a polyfunctional monomer having at least two polymerizable carbon-carbon double bonds in the molecule may be used, and a monofunctional group may be used. The base monomer is preferred. Examples of the monofunctional monomer include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, halogenated styrene, and hydroxystyrene; and ethylene such as acrylonitrile and methacrylonitrile. a cyano compound; an unsaturated acid such as acrylic acid, methacrylic acid, maleic anhydride, or methylene succinic anhydride; such as N-methyl maleimide, N-cyclohexylmaleimide, N - Maleidin of phenylmaleimide; such as Methallyl alcohol, allyl alcohol; vinyl acetate, vinyl chloride, ethylene, propylene, 4-methyl- 1-pentene, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, N-vinyl carbazole, and the like.

Further, examples of the polyfunctional monomer include polyunsaturated polyvalent alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylolpropane trimethacrylate. a carboxylic acid ester; an enester of an unsaturated carboxylic acid such as allyl acrylate, allyl methacrylate or allyl cinnamate; such as diallyl phthalate or diallyl maleate A polyene ester of a polybasic acid of triallyl cyanurate or triallyl isocyanurate; an aromatic polyene compound such as divinylbenzene.

The other polymerizable monomers described above may be copolymerized in a single type or in combination of two or more kinds.

The (meth)acrylic resin is preferably from 50 to 100% by weight based on the total amount of the monomers used for the polymerization, and the other polymerizable monomer is from 0 to 50% by weight, more preferably It is 50 to 99.9% by weight of the alkyl methacrylate and 0.1 to 50% by weight of the other polymerizable monomer.

Further, the (meth)acrylic resin may have a ring structure in the polymer main chain because the durability of the film can be improved. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic quinone imine structure, or a lactone ring structure. Specific examples thereof include a cyclic acid anhydride structure such as a glutaric anhydride structure and a succinic anhydride structure, a cyclic quinone imine structure such as a glutarylene imine structure or an amber quinone structure, butyrolactone and valerolactone. The structure of the lactone ring. When the content of the ring structure of the polymer main chain is high, the glass transition temperature of the (meth)acrylic resin can be increased.

The cyclic acid anhydride structure of the polymer main chain of the (meth)acrylic resin and the introduction of the cyclic quinone imine structure can be obtained by maleic acid a method of copolymerizing a monomer having a cyclic structure such as an anhydride or maleimide; a method of introducing a cyclic acid anhydride by a dehydration/decoholization condensation reaction after polymerization; and reacting an amine compound in a cyclic structure It is carried out by a conventional method such as a method of introducing a cyclic quinone imine structure.

Further, the introduction of the lactone ring structure of the polymer main chain of the (meth)acrylic resin can be carried out by preparing a (meth)acrylic resin having a hydroxyl group and an ester group in the polymer chain, and then the hydroxyl group of the resin and The ester group is carried out by heating, if necessary, by cyclization condensation in the presence of a catalyst such as an organic phosphorus compound. Preparation of a (meth)acrylic resin having a hydroxyl group and an ester group in a polymer chain, for example, by using methyl 2-(hydroxymethyl)(meth)acrylate or 2-(hydroxymethyl)(methyl) Ethyl acrylate, isopropyl 2-(hydroxymethyl)(meth)acrylate, n-butyl 2-(hydroxymethyl)(meth)acrylate, 2-(hydroxymethyl)(meth)acrylic acid third A (meth) acrylate having a hydroxyl group and an ester group of a butyl ester, which is obtained by copolymerization of a (meth)acrylic resin. A more specific preparation method of the (meth)acrylic resin having a lactone ring structure is disclosed in, for example, Japanese Laid-Open Patent Publication No. 2007-254726.

The (meth) acrylate described above can be prepared by radical polymerization of a (meth) acrylate or a monomeric (meth) acrylate and a monomer composition containing another polymerizable monomer. In the preparation of the (meth)acrylic resin, a solvent or a polymerization initiator may be used as needed.

The (meth)acrylic resin film may contain other resins than the above (meth)acrylic resin. The content ratio of the other resin is preferably from 0 to 50% by weight, more preferably from 0 to 25% by weight, still more preferably from 0 to 10% by weight, based on the total amount of the resin. The a resin such as polyethylene, polypropylene, ethylene-propylene copolymer, poly(4-methyl-1-pentene) olefin polymer; halogen-containing polymer such as vinyl chloride or vinyl chloride resin; Styrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer styrene polymer; such as polyethylene terephthalate, polybutylene terephthalate, polynaphthalene a polyester of diethyl formate; a polyaryl ester composed of an aromatic diol and an aromatic dicarboxylic acid; a biodegradable polyester such as polylactic acid or dibutyl polysuccinate; a polycarbonate; such as nylon 6, Nylon 66, nylon 610 polyamide; polyacetal; polyphenylene ether; polyphenylene sulfide; polyether ether ketone; polyether nitrile; polyfluorene; polyether oxime; polyoxybenzoic acid methyl ester; polyamine oxime Amines, etc.

The (meth)acrylic resin film preferably contains acrylate rubber particles at the point of impact resistance and film forming properties of the film. The amount of the acrylate rubber particles contained in the (meth)acrylic resin is preferably 5% by weight or more, and more preferably 10% by weight or more based on 100% by weight of the (meth)acrylic resin. The upper limit of the amount of the acrylate rubber particles is not critical, but when the amount of the acrylate rubber particles is too large, the surface hardness of the film is lowered, and in the case of performing surface treatment on the film, the solvent resistance to the organic solvent in the surface treatment agent Will decrease. Therefore, the amount of the acrylate rubber particles contained in the (meth)acrylic resin is preferably 80% by weight or less, more preferably 60% by weight or less.

The acrylate rubber particles are particles in which an elastic polymer mainly composed of acrylate is an essential component, and may be a single layer structure composed of only the elastic polymer, or a multilayer structure in which the elastic polymer is one layer. By. As the elastic polymer, specifically, the use of C 50 to 99.9% by weight of an alkylene olefinate, 0 to 49.9% by weight of at least one other vinyl monomer copolymerizable therewith, and 0.1 to 10% by weight of a monomer of a copolymerizable crosslinking monomer. Crosslinked elastomeric copolymers are preferred.

The alkyl acrylate may, for example, be methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate. The alkyl group has a carbon number of usually about 1 to 8. Further, as another vinyl monomer copolymerizable with the above alkyl acrylate, for example, a compound having one polymerizable carbon-carbon double bond in the molecule may be mentioned, and more specifically, for example, methyl methacrylate may be mentioned. A acrylate, an aromatic vinyl compound such as styrene, a vinyl cyanide compound such as acrylonitrile, or the like. In addition, examples of the copolymerizable crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, for example, ethylene glycol di(methyl). (meth) acrylate of polyvalent alcohol of acrylate, butanediol di(meth) acrylate, allyl (meth) acrylate, (meth) acrylate of methyl allyl methacrylate Enester, divinylbenzene, and the like.

The (meth)acrylic resin film may contain, in addition to the above acrylate rubber particles, a usual additive such as an ultraviolet absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, a charge preventive agent, or a surfactant. Wait. Among them, it is preferable to use an ultraviolet absorber in improving weather resistance. As an example of the ultraviolet absorber, for example, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2- Phenol], 2-(5-methyl-2-hydroxyphenyl)-2H-benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl Phenyl]-2H-benzotriazole, 2-(3,5-dibutylbutyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(3-tert-butyl-5 -methyl-2- Hydroxyphenyl)-5-chloro-2H-benzotriazole, 2-(3,5-dibutylbutyl-2-hydroxyphenyl)-5-chloro-2H-benzotriazole, 2-( 3,5-di 3 pentyl-2-hydroxyphenyl)-5-chloro-2H-benzotriazole, 2-(2'-hydroxy-5'-3th octylphenyl)-2H-benzene a triazole-based benzotriazole-based ultraviolet absorber; such as 2-hydroxy-4-methoxydiphenyl ketone, 2-hydroxy-4-octyloxydiphenyl ketone, 2,4-dihydroxydiphenyl Ketone, 2-hydroxy-4-methoxy-4'-chlorodiphenyl ketone, 2,2'-dihydroxy-4-methoxydiphenyl ketone, 2,2'-dihydroxy-4, 4-hydroxydiphenyl ketone UV absorber of 4'-dimethoxydiphenyl ketone; such as salicylic acid p-tert-butylphenyl ester, p-octylphenyl salicylate salicylic acid benzene For the ester-based ultraviolet absorber or the like, two or more of these may be used as needed. When the (meth)acrylic resin contains a UV absorber, the amount thereof is usually 0.1% by weight or more, preferably 0.3% by weight or more, based on 100% by weight of the (meth)acrylic resin, and more preferably 2% by weight or less.

For the production of the (meth)acrylic resin film, a conventional film forming method can be employed. The (meth)acrylic resin film system may have a multilayer structure, and a (meth)acrylic resin film having a multilayer structure may be, for example, a conventional method using a feed module or a method using a multi-manifold die. . Among them, for example, a method in which a multilayer structure is formed by laminating a T-die from a T-die by melt-extrusion molding, and at least one surface of the obtained laminated film is brought into contact with a roller or a belt to obtain a surface property. The point of the film is ideal. In particular, from the viewpoint of improving the surface smoothness and surface glossiness of the (meth)acrylic resin film, it is preferable to form a film of the laminated film obtained by the above-mentioned multilayer melt-molding and contact with a roller or a belt. . In the roller or belt used at this time, with (meth) propyl In order to impart smoothness to the (meth)acrylic resin film, the surface of the roller to be contacted with the olefinic resin is preferably a mirror surface.

In the (meth)acrylic resin film, in order to obtain a film having desired optical properties and mechanical properties, the film produced in the above manner can be subjected to stretching treatment. As the stretching treatment, for example, one-axis stretching, biaxial stretching, or the like can be given. Examples of the extending direction include a mechanical moving direction (MD) of the unstretched film, a direction (TD) perpendicular thereto, a direction inclined to the mechanical moving direction (MD), and the like. The two-axis extension may be a simultaneous two-axis extension extending in two extending directions, or may be a second-axis extension extending in other directions after extending in a predetermined direction.

For the extension treatment, for example, two or more pairs of clamping rollers having a large rotation speed on the outlet side may be used to extend in the longitudinal direction (mechanical movement direction: MD), or both ends of the unstretched film may be held by the chuck, perpendicular to The direction of the mechanical movement direction (TD) is expanded to proceed.

The elongation treatment is performed by the following formula: extension ratio (%) = 100 × {(length after extension) - (length before extension)} / length before extension

The stretch ratio obtained is preferably greater than 0% and preferably less than 300%, and more preferably 100 to 250%. When the stretching ratio exceeds 300%, the film thickness becomes too thin to be easily broken, or the usability is lowered.

Further, in order to impart desired optical characteristics and mechanical properties, a treatment for shrinking the film is carried out instead of the stretching treatment or by bonding a heat-shrinkable film to the (meth)acrylic resin film.

The thickness of the (meth)acrylic resin film is thin and reasonable. I think, if it is too thin, it will become weaker and the workability will be worse. On the other hand, when it is too thick, the transparency will be lowered, or the weight of the polarizing plate will become heavier. Therefore, the appropriate thickness of the film is, for example, about 5 to 200 μm, more preferably 10 to 150 μm, still more preferably 20 to 100 μm.

[Transparent resin film]

The polarizing plate may have a transparent resin film laminated on the surface opposite to the (meth)acrylic resin film of the polarizing film via an adhesive. The transparent resin film may be a protective film or another optical film. However, when it is disposed on the liquid crystal cell side, it is preferably an unaligned film or a liquid crystal display mode (TN mode, VA mode, IPS mode, etc.). An optical compensation film (retardation film) showing phase difference characteristics. The transparent resin film may be a (meth)acrylic resin film or a transparent resin film different from the (meth)acrylic resin film.

In addition to the above (meth)acrylic resin film, the transparent resin film may be, for example, a cyclic olefin resin film, a cellulose resin film, a polycarbonate resin film, or a chain polyolefin resin film (polyethylene). A resin film, a polypropylene resin film or the like), a polyester resin film (such as a polyethylene terephthalate resin film), or the like.

The cyclic olefin resin film is a film composed of a cyclic olefin resin. The cyclic olefin-based resin is, for example, a thermoplastic resin having a monomer unit composed of a cyclic olefin such as norbornene or a polycyclic norbornene-based monomer. The cyclic olefin-based resin may be a ring-opening polymer of the above cyclic olefin or a hydrogenated product of a ring-opening copolymer of two or more kinds of cyclic olefins, and may be a cyclic olefin and a chain olefin, and may have ethylene. An addition copolymer of a base aromatic compound. Moreover, it is also effective to introduce a polar base.

In the case of an addition copolymer of a cyclic olefin-based cyclic olefin, a chain olefin, or an aromatic compound having a vinyl group, examples of the chain olefin include, for example, ethylene or propylene, and have a vinyl group. Examples of the aromatic compound include styrene, α-methylstyrene, and a core alkyl-substituted styrene. In such a copolymer, the monomer unit containing a cyclic olefin is 50 mol% or less, and may be, for example, about 15 to 50 mol%. Particularly in the case of a terpolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the monomer unit containing a cyclic olefin may be in a small amount as described above. In such a terpolymer, the monomer unit containing a chain olefin is usually about 5 to 80 mol%, and the monomer unit containing an aromatic compound having a vinyl group is usually about 5 to 80 mol%.

As a commercially available thermoplastic cyclic olefin resin, there are "Topas" (made by TOPAS ADVANCED POLYMERS GmbH, available from Polyplastics), "Arton" (JSR), and "ZEONOR". (Japan ZEON (share)), "ZEONEX" (Japan ZEON (share)), "APEL" (Mitsui Chemical (share) system) (all are trade names).

The cyclic olefin resin film can be imparted with an arbitrary retardation value by stretching. Thereby, an appropriate optical compensation function can be imparted, and the viewing angle contributing to the liquid crystal display device can be expanded. The in-plane retardation value R _{0 of the} extended cyclic olefin-based resin film is preferably 40 to 100 nm, more preferably 40 to 80 nm. When the in-plane retardation value R _{0 is} less than 40 nm or exceeds 100 nm, the viewing angle compensation ability of the liquid crystal panel tends to be lowered. Further, the thickness direction phase difference _{Rth of the} extended cyclic olefin-based resin film is preferably 80 to 300 nm, more preferably 100 to 250 nm. When the thickness direction phase difference _{Rth is} less than 80 nm or exceeds 300 nm, the viewing angle compensation ability of the liquid crystal panel tends to be lowered as described above.

The in-plane retardation value R ₀ and the thickness direction retardation value R _{th of the} extended cyclic olefin resin film are respectively represented by the following formulas (1) and (2): R ₀ = (n _{x -} n _y ) × d ( 1)

Rth=[(n _x +n _y )/2-n _z ]×d (2) can be measured, for example, using KORBRA21ADH (manufactured by Oji Scientific Instruments Co., Ltd.). In the above formulas (1) and (2), n _x is a refractive index in the in-plane retardation axis direction of the extended cyclic olefin resin film, and n _y is an in-plane advanced axis direction of the extended cyclic olefin resin film ( The refractive index in the direction perpendicular to the in-plane retardation axis direction, n _z is the refractive index in the thickness direction of the extended cyclic olefin resin film, and d is the thickness of the extended cyclic olefin resin film.

The extension of the cyclic olefin-based resin film is usually continuously extended from the film roll, and is extended in the direction in which the roller travels or in the direction perpendicular to the traveling direction by a heating furnace. The temperature of the heating furnace is usually in the range from about the vicinity of the glass transition temperature of the cyclic olefin resin to about 100 ° C higher than the glass transition temperature. The magnification of the extension is usually from 1.1 to 6 times, more preferably from 1.1 to 3.5 times. The film-formed and extended cyclic olefin-based resin may be commercially available, and under the trade name, "ESCENA" (made by Sekisui Chemical Industry Co., Ltd.), "SCA40" (made by Sekisui Chemical Industry Co., Ltd.), NEONOR FILM" (Japan ZEON).

The cyclic olefin resin film is generally subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, and saponification treatment on the surface adjacent to the polarizing film due to poor surface activity. It is ideal. Among them, plasma treatment and corona treatment which are relatively easy to implement are suitable.

The thickness of the cyclic olefin-based resin film is preferably as small as possible, but when it is too thin, the strength is lowered and the workability is deteriorated. On the other hand, when it is too thick, the transparency is lowered, or the weight of the polarizing plate is increased. Therefore, the appropriate thickness of the film is, for example, about 5 to 200 μm, more preferably 10 to 150 μm, still more preferably 20 to 100 μm.

The cellulose-based resin film is usually a cellulose-based resin containing a partially or completely acetated cellulose, and examples thereof include a triethylenesulfonated cellulose film, a diethyl fluorinated cellulose film, and a cellulose acetate. Propionate film and the like. For example, "FUJITAC TD80" (Fuji Film Co., Ltd.), "FUJITAC TD80UF" (Fuji Film Co., Ltd.), and "FUJITAC TD80UZ" ("FUJITAC TD80UZ") are commercially available. Fujifilm Co., Ltd., "FUJITAC TD40UZ" (Fuji Film Co., Ltd.), "KC8UX2M" (Konica Minolta Co., Ltd.), and "KC4UY" (Konica Minolta Co., Ltd.) , "KC8UY" (Konica Minolta (share) system) and so on.

On the surface of the cellulose resin film, surface treatment such as antiglare treatment, hard coating treatment, antistatic treatment, and antireflection treatment can be performed depending on the application. The cellulose resin film may be extended to impart an arbitrary retardation value.

The cellulose resin film is usually subjected to a saponification treatment in order to improve the adhesion to the polarizing film. As the saponification treatment, a method of immersing in an aqueous solution of a base such as sodium hydroxide or potassium hydroxide can be employed.

The thickness of the cellulose resin film is thin, but it is ideal, but When it is too thin, the strength is lowered and the workability is deteriorated. On the other hand, when it is too thick, the transparency is lowered, or the weight of the polarizing plate is increased. Therefore, the appropriate thickness of the film is, for example, about 5 to 200 μm, more preferably 10 to 150 μm, still more preferably 20 to 100 μm.

[adhesive agent]

The (meth)acrylic resin film or the transparent resin film is bonded to the polarizing film via an adhesive. The adhesive used for the polarizing film and the (meth)acrylic resin film, and the adhesive used for the polarizing film and the transparent resin film may be different types or may be the same type. Considering the ease of construction, etc., it is advantageous to use the same adhesive on both sides.

As the adhesive, from the viewpoint of thinning the adhesive layer, the water system may be, for example, one in which the adhesive component is dissolved in water or dispersed in water. For example, a composition using a polyvinyl alcohol-based resin or an amine ester resin as a main component is preferably a preferred adhesive.

In the case where a polyvinyl alcohol-based resin is used as a main component of the adhesive, the polyvinyl alcohol-based resin may be a carboxyl group-modified polyvinyl alcohol or a group other than the partially saponified polyvinyl alcohol or the fully saponified polyvinyl alcohol. A polyvinyl alcohol-based resin modified with a polyvinyl alcohol-modified polyvinyl alcohol, a methylol-modified polyvinyl alcohol, or an amine-modified polyvinyl alcohol. In this case, an aqueous solution of a polyvinyl alcohol-based resin is used as an adhesive. The concentration of the polyvinyl alcohol-based resin in the subsequent agent is usually from 1 to 10 parts by weight, preferably from 1 to 5 parts by weight, per 100 parts by weight of water.

An adhesive containing an aqueous solution of a polyvinyl alcohol-based resin is hardened by adding glyoxal or a water-soluble epoxy resin in order to improve adhesion. Sexual components and cross-linking agents are preferred. As the water-soluble epoxy resin, for example, a polyamidamine obtained by reacting a polyalkyleneamine such as di-ethyltriamine or tri-ethyltetramine with a dicarboxylic acid such as adipic acid can be suitably used. A polyamidamine polyamine epoxy resin obtained by reacting with epichlorohydrin. For example, "SUMIRESIN 650" (manufactured by Sumitomo CHEMTEX Co., Ltd.), "SUMIRESIN 675" (manufactured by CHIMTEX Co., Ltd.), and "WS-" are commercially available products. 525" (Japan PMC (share) system) and so on. The amount of the curable component and the crosslinking agent to be added (the total amount of the curable component and the crosslinking agent to be added is a total amount thereof), and is usually 1 to 100 parts by weight based on 100 parts by weight of the polyvinyl alcohol resin. It is preferably from 1 to 50 parts by weight. When the amount of the curable component and the crosslinking agent added is less than 1 part by weight based on 100 parts by weight of the polyvinyl alcohol-based resin, the effect of improving the adhesion tends to be small, and the curable component and the crosslinking agent are preferable. When the amount of addition exceeds 100 parts by weight based on 100 parts by weight of the polyvinyl alcohol-based resin, the adhesive layer tends to become brittle.

Further, in the case of using an urethane resin as a main component of the adhesive, as an example of a suitable adhesive composition, for example, a polyester-based ionic polymer-type amine ester resin and having a glycidoxy group (for example) A mixture of compounds of glycidyloxy). The polyester-based ionic polymer-type amine ester resin is an amine ester resin having a polyester skeleton, and a small amount of an ionic component (hydrophilic component) is introduced therein. Such an ionic polymer type amine ester resin is emulsified directly in water to form an emulsion without using an emulsifier, and is suitable as a water-based adhesive.

The polyester-based ionic polymer type amine ester resin itself is conventionally known. For example, Japanese Laid-Open Patent Publication No. Hei. In the publication, a mixture of a polyester-based ionic polymer-type amine ester resin and a compound having a glycidoxy group as a binder is used, and a cyclic olefin-based resin film is bonded to a polarizing film containing a polyvinyl alcohol-based resin.

The method of bonding the (meth)acrylic resin film or the transparent resin film to the polarizing film is usually a conventional method, and may be, for example, a flow casting method or a Meyer bar coating method. a gravure coating method, a notch wheel coating method, a doctor blade method, a slit coating method, a dip coating method, a spray method, or the like, and applying an adhesive to a polarizing film and/or a bonding surface of a film bonded thereto, The method of overlapping the two. The casting method is a method in which the film of the object to be coated is caused to flow down to the surface of the object to be coated in a direction perpendicular to the direction of the vertical direction, in the direction parallel to the direction of inclination, or the like.

After the adhesive is applied by the above method, the polarizing film and the film bonded thereto are bonded by being sandwiched by a pinch roller. Further, it is also suitable for use in a method in which a polarizing film and a film bonded thereto are dropped, and the laminate is pressurized by a roller or the like and uniformly spread. In this case, metal, rubber, or the like can be used as the material of the roller. Further, a method in which the laminate is dropped between the polarizing film and the film bonded thereto, and the laminate is passed between the roller and the roller to be pressurized and expanded is preferable. In this case, the rollers may be of the same material or different materials.

For polarizing film laminated (meth)acrylic resin film and transparent The order of the resin film is not particularly limited, and any film may be laminated on the polarizing film to laminate another film, or a method in which the two films are substantially simultaneously laminated on the polarizing film may be employed.

Further, in order to improve the adhesion on the surface of the adhesive layer, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, and saponification treatment can be suitably performed. The saponification treatment may, for example, be a method of immersing in an aqueous solution of a base such as sodium hydroxide or potassium hydroxide.

The laminate which is bonded through the water-based adhesive is usually subjected to a drying treatment to dry and harden the adhesive layer. The drying treatment can be carried out, for example, by blowing hot air. The drying temperature is suitably selected from the range of from 40 to 100 ° C, preferably from 60 to 100 ° C. The drying time is, for example, about 20 to 1200 seconds. The thickness of the adhesive layer after drying is usually about 0.001 to 5 μm, preferably 0.01 μm or more, and more preferably 2 μm or less, and still more preferably 1 μm or less. When the thickness of the layer is too thick, the appearance of the polarizing plate tends to be poor.

After the drying treatment, the curing can be carried out at a temperature of at least room temperature for at least half a day, usually for several days or more, to obtain a sufficient bonding strength. Such maintenance is typically carried out in a state of being rolled into a roll. A preferred conditioning temperature is in the range of 30 to 50 ° C, more preferably 35 to 45 ° C. When the curing temperature exceeds 50 ° C, it is likely to cause "winding" in a state of being wound into a roll. Further, the humidity during the maintenance is not particularly limited, and it is preferable to select a range in which the relative humidity is 0 to 70% RH. The time of health is usually about 1 to 10 days, preferably about 2 to 7 days.

Further, as the adhesive, an active energy ray-curable adhesive can be used. The active energy ray used for curing the active energy ray-curable adhesive is, for example, X-ray, ultraviolet ray, or visible light. Among them, ultraviolet rays are preferably used from the viewpoints of easiness of use, ease of preparation of the adhesive composition, stability, and curing performance. When the active energy ray-curable adhesive is used, the drying process is not required as compared with the case of using the water-based adhesive, and the procedure is shortened and the energy efficiency is increased. In the case where the (meth)acrylic resin film is used, the drying time is prolonged, and in the polarizing plate of the present invention containing the (meth)acrylic resin film, the active energy ray is used in the adhesive layer. A sclerosing adhesive is particularly effective.

The photocurable adhesive agent may, for example, be a mixture of a photocurable epoxy resin and a photocationic polymerization initiator (that is, an epoxy photocurable adhesive), a photocurable (meth)acrylic resin, and light. A mixture of a radical polymerization initiator or the like (that is, a (meth)acrylic photocurable adhesive). These photocurable adhesives may be used singly or in combination. The photocurable adhesive can be cured by irradiation with an active energy ray. The light source of the active energy ray is not particularly limited, and is preferably an active energy ray (ultraviolet light) having a light-emitting distribution of a wavelength of 400 nm or less. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, Black light, microwave excited mercury lamp, metal halide lamp, etc. are ideal.

The light irradiation intensity of the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive, and is not particularly limited, and the irradiation intensity in the wavelength region effective for activation of the polymerization initiator is 0.1 to 6000 mW/cm ^{2 .} More ideal. When the irradiation intensity is 0.1 mW/cm ² or more, the reaction time does not become too long, and the heat generated by the light source and the heat generated by curing of the photocurable adhesive are generated by 6000 mW/cm ² or less. The yellowing of the oxygen resin and the deterioration of the polarizing film are less likely to occur. The light irradiation time of the photocurable adhesive is controlled by the photocurable adhesive which is to be cured, and is not particularly limited, and the cumulative light amount indicating the product of the irradiation intensity and the irradiation time is set to 10 to 10000 mJ/ m ² is ideal. When the cumulative amount of light of the photocurable adhesive is 10 mJ/m ² or more, the active species from the polymerization initiator is generated in a sufficient amount, and the active species derived from the polymerization initiator can be sufficiently generated to more reliably perform the hardening reaction. Moreover, by 10000 mJ/m ² or less, the irradiation time does not become too long, and good productivity can be maintained. Further, the thickness of the adhesive layer after the irradiation of the active energy ray is usually about 0.001 to 5 μm, preferably 0.01 μm or more and 2 μm or less, more preferably 0.01 μm or more and 1 μm or less.

When the photocurable adhesive is cured by irradiation with an active energy ray, a polarizing plate such as a polarizing film, a transmittance, a hue, and a transparency of the (meth)acrylic resin film and the transparent resin film are used. It is desirable to perform hardening under various conditions without degrading.

[Adhesive layer]

The polarizing plate may be provided on the outer side of the transparent resin film (that is, the surface on the side opposite to the polarizing film side), and may have an adhesive layer for bonding the polarizing plate to the liquid crystal cell. As the adhesive to be used for the adhesive layer, a conventionally known suitable adhesive can be used without particular limitation, and examples thereof include an acrylic adhesive, an amine ester adhesive, a silicone resin adhesive, and a polyester adhesive. Agent An amine-based adhesive, a polyether-based adhesive, a fluorine-based adhesive, a rubber-based adhesive, or the like. Among them, an acrylic adhesive is preferred from the viewpoints of transparency, adhesion, reliability, and reworkability. The adhesive layer can be applied by applying a method such as an organic solvent solution to a transparent resin film by a slit coater or a gravure coater, and drying it. It can be provided by a method of transferring a sheet-like adhesive formed on a plastic film (referred to as a release film) which has been subjected to release treatment to a transparent resin film. It is preferable to attach a release film to the surface of the adhesive layer by either method. The thickness of the adhesive layer is not particularly limited, and is generally preferably in the range of 2 to 40 μm.

The constituent material of the release film may be a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or the like. Among them, a stretch film of polyethylene terephthalate is preferred.

The release treatment layer to which the release film is applied is not particularly limited as long as it has release properties, and may be a type of a cured epoxy resin as a main component, and may be used by using an amine ester resin, an epoxy resin, or an alcohol. A type of modified epoxy resin such as graft polymerization of an organic resin such as an acid resin, etc., among these, it is preferable that the curable epoxy resin is a main component.

[Surface protective film]

The polarizing plate may have a surface protective film (referred to as a protective film) laminated on the outer surface of the (meth)acrylic resin film. In order to prevent damage of the (meth)acrylic resin film and adhesion of dust, the surface protective film is usually laminated on the (meth)acrylic resin film via an adhesive.

The constituent material of the surface protective film may, for example, be a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester resin such as polyethylene terephthalate. Among them, from the viewpoint of moisture permeability and mechanical strength, a stretch film of polyethylene terephthalate is preferred.

For the specific description of the adhesive layer for attaching the surface protective film, the description of the above-mentioned adhesive layer is cited. For the specific description of the release treatment layer to which the surface protective film is applied, the description of the release treatment layer for imparting the release film is also cited.

[example]

Hereinafter, the present invention will be more specifically described by showing examples, but the present invention is not limited to the examples.

<Manufacturing example: Production of polarizing plate for end face processing>

An end face processed polarizing plate having a (meth)acrylic resin film was produced in the following procedure. A polyvinyl alcohol film having an average polymerization degree of 2400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30° C., and then immersed in an iodine/potassium iodide/water weight ratio of 0.02/2/100 at 30° C. Aqueous solution. Then, it was immersed in an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 12/5/100 at 56.5 °C. Subsequently, it was washed with pure water at 8 ° C, and then dried at 65 ° C to obtain a polarizing film in which iodine was adsorbed and aligned to polyvinyl alcohol. The extension system was mainly carried out in the steps of iodine dyeing and boric acid treatment, and the total stretching ratio was 5.3 times.

On the surface of one side of the obtained polarizing film, a (meth)acrylic resin film having a thickness of 80 μm (an acrylic resin film obtained by adding 30% by weight of acrylic rubber particles to all the resin compositions) was used. The side of one side will contain opticals of a cyclic olefin resin having a thickness of 50 μm. The compensation film was subjected to a corona treatment on the bonding surface, and then a polarizing plate was obtained through a photocurable adhesive (epoxy photocurable adhesive).

Then, a surface protective film (extended polyethylene terephthalate film) having an acrylic pressure-sensitive adhesive layer is provided on the outer surface of the (meth)acrylic resin film of the obtained polarizing plate, and is also a cyclic olefin system. An acrylic adhesive layer having a thickness of 20 μm is provided on the outer surface of the optical compensation film made of the resin, and a release film (extended polyethylene terephthalate) which is subjected to release treatment is attached to the outside of the adhesive layer. Ester film). Then, it was cut into a size of 1031 mm × 588 mm to obtain a polarizing plate for end face processing.

<Example 1>

The polarizing plate for end surface processing obtained by the above-mentioned manufacturing example was laminated on four sides to obtain a polarizing plate laminated body W. Then, using the end surface processing apparatus shown in Fig. 1, the polarizing plate laminate W is fixed to the end surface processing apparatus, and the end faces are processed as shown in Fig. 2(a) and (b). 41, 42, 43, and 44 are all cut. The processing conditions of the four end faces 41, 42, 43, and 44 are identical.

Specifically, the cutting tools 10 and 11 are rotated about the rotation axis thereof, and the polarizing plate laminated body W is horizontally moved in the x direction while the positions of the cutting tools 10 and 11 are fixed, thereby the polarizing plate. The longitudinal ends of the end faces 41 and 42 of the laminated body W are parallel, and the cutting tools 10 and 11 relatively move the polarizing plate laminated body W, and the cutting inserts 10a and 11a abut against the end faces 41 and 42 to cut the end faces and perform cutting work. The moving direction of the polarizing plate laminate W and the rotation direction of the cutting tools 10 and 11 are as shown in Fig. 2(a). The relative movement described above, from one end of each end face to the other end In the row, the relative movement (cutting) is repeated for the same end face a total of 5 times.

Then, the polarizing plate laminate W is rotated by 90 degrees by the rotary table 31 and the presser 30, and the cutting tools 10 and 11 are rotated about the rotation axis as in the case of the end faces 41 and 42, and at the same time, in the cutting tool When the positions of 10 and 11 are in a fixed state, the polarizing plate laminated body W is horizontally moved in the x direction, whereby the longitudinal direction of the end faces 43 and 44 of the polarizing plate laminated body W is parallel, and the cutting tools 10 and 11 are paired with the polarizing plate. The laminated body W relatively moves, and the cutting inserts 10a and 11a abut against the end faces 43, 44 to cut the end faces and perform cutting work. The moving direction of the polarizing plate laminate W and the rotation direction of the cutting tools 10 and 11 are as shown in Fig. 2(b). The relative movement is performed from one end to the other end of each end face, and the relative movement (cutting) is repeated for the same end face a total of five times.

The various configurations of the configuration of the end surface processing apparatus and the end surface processing are as follows.

‧Cutting tools 10, 11: cylindrical rotating body with one cutting insert on the side

‧An angle between the rotation axis of the cutting tools 10 and 11 and the extending direction of the cutting insert: 0 degrees

‧An angle α between the rotation axis of the cutting tools 10 and 11 and the lamination direction z of the polarizing plate: 0 degrees

‧ Rotating speed of cutting tools 10, 11: as shown in Table 1 below (5000 rpm)

‧The number of relative movements: 5 times for each end face

‧The relative shift between the polarizing plate laminate W and the cutting tools 10, 11 Dynamic speed: as shown in Table 1 below (500mm/min)

‧The number of times the above definition is reached: 1000 times

‧1 depth of cut defined above: as shown in Table 1 below

‧The total depth of cut defined above: as shown in Table 1 below (1.00mm)

‧Durmination depth at the completion of the above definition: as shown in Table 1 below (0.04mm)

In any of the cutting processes, it was confirmed that the end portions of the respective polarizing plates were not peeled off from the (meth)acrylic resin film, and the end faces of the respective polarizing plates were collected in a well-completed state.

<Comparative Example 1>

The end faces 41, 42, 43, and 44 were all cut in the same manner as in the first embodiment except that the number of relative movements, the depth of one cut, and the depth of cut at the time of completion were changed as shown in Table 1. In any of the cutting processes, it was confirmed that the end portions of the respective polarizing plates were not peeled off from the (meth)acrylic resin film, and the end faces of the respective polarizing plates were collected in a well-completed state.

(Evaluation of impact resistance of end face processing polarizer)

In the end face processing polarizing plate obtained in Example 1, the maximum impact energy (hereinafter referred to as "maximum impact energy") at which no peeling of the (meth)acrylic resin film was generated was measured at the end portion of the polarizing plate to evaluate the end face processing. Impact resistance at the end of the polarizing plate. The results are shown in Table 1. The specific measurement sequence is as follows.

The end face processing polarizing plate was cut into a size of 25 mm (MD) × 50 mm (TD) to prepare a measurement sample. After the measurement sample was fixed to a test bench of a cross-sectional impact tester (stiffness tester) [No. 2049-M manufactured by Kumagai Riki Co., Ltd.], a pendulum with a load was attached. Fall The end face of the measurement sample at the lowest point of the pendulum was subjected to an impact on the end surface, and the end surface was observed with an optical microscope to confirm the presence or absence of peeling between the (meth)acrylic resin film and the polarizing film. The test was repeated 5 times with the same amount of impact, and the case where peeling occurred twice was "with peeling". Then, the impact amount of each pendulum was changed, and the same test was performed to obtain the above maximum impact energy (mJ). The impact amount of the pendulum is changed by adjusting the weight of the load imparted to the pendulum, the distance from the rotary shaft of the pendulum to the load, and the initial drop position of the pendulum. The upper limit of the impact energy that can be measured by the profile impact tester used is 19.4 mJ.

The end face processed polarizing plate obtained in Comparative Example 1 showed extremely small maximum impact energy as compared with the examples.

<Examples 2 to 4, Comparative Example 2>

The end faces 41, 42, 43, and 44 were all cut in the same manner as in the first embodiment except that the number of times of contact and the relative movement speed were changed as shown in Table 2. In any of the cutting processes, it was confirmed that the end portions of the respective polarizing plates were not peeled off from the (meth)acrylic resin film, and the end faces of the respective polarizing plates were collected in a well-completed state. In Table 2, for reference, Example 1 is shown in combination.

In Table 2, ">19.4" means that no peeling occurred even if the upper limit of the impact energy which can be measured by the cross-sectional impact tester used was 19.4 mJ.

10, 11‧‧‧ cutting tools

10a, 11a‧‧‧ cutting inserts

20‧‧‧Upper press

21‧‧‧ Lower press

30‧‧‧Brazil

31‧‧‧Rotating table

W‧‧‧Polarized plate laminate

Claims (9)

A method for producing a face-finished polarizing plate, comprising: forming a plurality of stacked polarizing films comprising a polarizing film comprising a polyvinyl alcohol-based resin and a (meth)acrylic resin film laminated thereon with an adhesive; a first step of exposing the polarizing plate laminate of the end surface; and cutting the processing of the cutting tool by moving the cutting tool relative to the polarizing plate laminate in the longitudinal direction of the end surface to obtain the second end face processing polarizer The cutting tool has n pieces which are parallel to the end surface and which are rotatable in a direction perpendicular to a longitudinal direction of the longitudinal direction of the end surface and which are rotatable in a direction extending from the rotation axis (where n represents 1) In the second step, the cutting step is performed by the cutting tool that rotates around the rotating shaft so that the end surface satisfies the following condition: (a) the n-piece cutting inserts are pressed The number of times of the end faces is 200 or more and 1,500 or less times per 100 mm in the longitudinal direction of the end surface; and (b) the relative Moving the cutting depth direction of the cutting depth of the end surface is 0.3mm or less. The method of claim 1, wherein the relative movement is performed from one end to the other end of the end surface in the longitudinal direction, and the relative movement from the one end to the other end is one time, and the end surface is plural Times. The method according to claim 2, wherein in the second step, the cutting is performed so that the total depth of cut in the depth direction is 0.2 mm or more and 1.5 mm or less. The method according to claim 2, wherein in the second step, the depth of the depth of the end surface cut by the last relative movement is 0.01 in a plurality of relative movements Cutting is performed in a manner of not more than 0.1 mm in mm. The method according to claim 1, wherein in the second step, two of the polarizing plate laminates are simultaneously processed by using the two cutting tools to simultaneously face the opposite end faces of the polarizing plate laminate. . The method according to claim 1, wherein the relative movement is performed by moving the polarizing plate laminate while the position of the cutting tool is fixed. The method according to the first aspect of the invention, wherein the polarizing plate comprises: the (meth)acrylic resin film laminated on the one surface of the polarizing film via an adhesive layer, and the other side surface Another transparent resin film laminated through the adhesive. The method according to claim 7, wherein the other transparent resin film is composed of a cyclic olefin resin. The method of claim 7 or 8, wherein the polarizing plate further comprises: an adhesive layer laminated on the outer surface of the other transparent resin film; and a release film laminated on the outer surface of the adhesive layer; A surface protective film laminated on the outer surface of the (meth)acrylic resin film.