JP6391442B2 - Cutting method, polarizing plate manufacturing method including cutting method, and polarizing plate - Google Patents

Description

  The present invention relates to a cutting method for cutting an end face of a polarizing plate, a manufacturing method for a polarizing plate including the cutting method, and a polarizing plate.

  In recent years, polarizing plates have been widely used for LCDs (Liquid Crystal Displays), infrared sensors, and other various applications. The polarizing plate is configured by laminating a resin film such as a polyvinyl alcohol film and a TAC (Tri Acetyl Cellulose) film.

  When the polarizing plate is used for various applications, for example, when mounted on an LCD, it is necessary to process it into a predetermined shape and dimensions according to the size of the LCD, and in particular, it is necessary to process the end face of the polarizing plate. is there. Moreover, when the cutting trace is formed in the end surface of a polarizing plate, the external appearance of a polarizing plate will be impaired and dimensional accuracy will fall. Therefore, it is very important to cut the end face of the polarizing plate with high accuracy.

  In order to perform the above-described processing, a cutting device in which a cutting blade is provided on a circumferential portion of a disk-shaped rotating plate is usually used. In the cutting apparatus, processing efficiency is taken into consideration, and it is possible to simultaneously process the end faces of the stacked polarizing plates. As a cutting method for accurately cutting the end face of the polarizing plate, for example, a cutting method using an end face cutting apparatus described in Patent Document 1 is known.

  By the way, in recent years, there has been widely used a polarizing plate in which a film made of at least a cycloolefin resin (hereinafter sometimes referred to as a COP film), an adhesive layer, and a polarizing film made of a polyvinyl alcohol resin are laminated in this order. It is used. However, the adhesion between the COP film and the polarizing film was insufficient. Therefore, before the film made of cycloolefin resin is bonded to the polarizing film via an adhesive layer (using an adhesive), the surface on the adhesive layer side is treated with an organic solvent to bond the film. A method for improving the adhesive force (affinity) with the agent layer is described in Patent Document 2.

JP 2007-223021 A (published September 6, 2007) JP 2012-177890 A (published September 13, 2012)

  By treating the surface of the adhesive layer side with an organic solvent, the adhesive force between a film made of a cycloolefin-based resin and a polarizing film made of a polyvinyl alcohol-based resin is improved. However, the impact resistance of the polarizing plate having the COP film and the polarizing film is still insufficient, and the conventional cutting method has a problem that peeling occurs between the COP film and the polarizing film. doing.

  As a result of diligent study on a cutting method to solve the above-described problems, a polarizing plate is conventionally obtained by bringing a cutting blade into contact with the end face of the polarizing plate along the direction from the polarizing film side toward the film side made of cycloolefin resin. It was ascertained that the cutting of the end face was the cause of peeling between the COP film and the polarizing film. That is, the present inventors have found that the direction in which the cutting blade is brought into contact with the end face of the polarizing plate is an important factor regarding whether or not peeling occurs.

  The present invention has been made in consideration of the above-mentioned problems, and the main purpose of the present invention is to prevent peeling between a film made of a cycloolefin resin and a polarizing film made of a polyvinyl alcohol resin without causing peeling. A cutting method for cutting an end face, a manufacturing method for a polarizing plate including the cutting method, and a polarizing plate manufactured by the manufacturing method and having an end face cut with high accuracy without causing peeling.

  As a result of intensive studies by the present inventors, the end face of the polarizing plate is brought into contact with the cutting blade along the direction from the film side made of cycloolefin resin to the polarizing film side without causing peeling. Has found that a polarizing plate cut with high accuracy can be obtained, and has completed the present invention.

  In order to solve the above problems, a cutting method according to the present invention is a polarizing plate formed by laminating a film made of a cycloolefin resin, a first adhesive layer, and a polarizing film made of a polyvinyl alcohol resin in this order. A cutting method for cutting an end face, wherein the film made of the cycloolefin resin has a surface on the adhesive layer side treated with an organic solvent, and the film side made of a cycloolefin resin on the end face of the polarizing plate The end face is cut by performing a cutting process in which a cutting blade is brought into contact along the direction from the side toward the polarizing film.

  In the cutting method according to the present invention, before performing the above cutting step, a stacking step of forming a polarizing plate stack by stacking a plurality of polarizing plates so that the stacking directions thereof are the same as each other is performed. preferable.

  Further, in the cutting method according to the present invention, the polarizing plate has a first adhesive layer and a first protective film in this order on the surface on the non-adhesive layer side in the film made of cycloolefin resin. Further, a laminated polarizing plate is more preferable.

  In the cutting method according to the present invention, the polarizing plate is a polarizing plate in which a second adhesive layer and a second protective film are further laminated in this order on the surface of the polarizing film on the non-adhesive layer side. It is more preferable that

  In the cutting method according to the present invention, the polarizing plate is a polarizing plate in which a second pressure-sensitive adhesive layer and a separate film are further laminated in this order on the surface of the first protective film on the non-adhesive layer side. More preferably, it is a plate.

  Further, in the cutting method according to the present invention, the cutting step is formed on the top surface of each of the cutting parts by rotating a rotating body including a plurality of cutting parts installed on an installation surface perpendicular to the rotation axis. More preferably, it is a step of cutting the end face by bringing the cut blade into contact with the end face of the polarizing plate.

  In the cutting method according to the present invention, in the cutting step, it is more preferable to move the rotating body relative to the polarizing plate while rotating the rotating body along the longitudinal direction of the cutting end face.

  The manufacturing method of the polarizing plate which concerns on this invention is characterized by including the said cutting method. In addition, the polarizing plate according to the present invention is manufactured by the above-described manufacturing method.

  According to the cutting method, the manufacturing method of the polarizing plate including the cutting method, and the polarizing plate according to the present invention, peeling between the film made of the cycloolefin resin and the polarizing film made of the polyvinyl alcohol resin does not occur. The polarizing plate whose end face is cut with high accuracy can be provided.

The end surface processing cutter which is a part of cutting device which cuts with the cutting method which concerns on this invention is shown, (a) is a side view, (b) is a front view. It is a perspective view which shows the attachment part of the cutting part in the said cutter for end surface processing. It is a perspective view which shows the cutting device provided with the said cutter for end surface processing.

  Hereinafter, an embodiment of the present invention will be described in detail. In the present specification, “A to B” indicates “A or more and B or less”.

  The cutting method according to the present invention is a cutting method for cutting an end face of a polarizing plate formed by laminating a film made of a cycloolefin resin, a first adhesive layer, and a polarizing film made of a polyvinyl alcohol resin in this order. In the film made of the cycloolefin resin, the surface on the adhesive layer side is treated with an organic solvent, and in the direction from the film side made of the cycloolefin resin to the polarizing film side on the end face of the polarizing plate. It is a method of cutting the said end surface by performing the cutting process which contacts a cutting blade along. Moreover, the manufacturing method which concerns on this invention is a method including the said cutting method.

  The polarizing plate cut by the cutting method according to the present invention is formed by laminating at least a film made of a cycloolefin resin, a first adhesive layer, and a polarizing film made of a polyvinyl alcohol resin in this order, and more preferably A first adhesive layer and a first protective film are further laminated in this order on the surface on the non-adhesive layer side of the film made of the cycloolefin resin, and more preferably, the non-adhesive layer in the polarizing film is not laminated. A second adhesive layer and a second protective film are further laminated in this order on the surface of the adhesive layer side, most preferably on the surface of the non-adhesive adhesive layer side of the first protective film. The second pressure-sensitive adhesive layer and the separate film are further laminated in this order. First, each structure which comprises a polarizing plate is demonstrated in order below.

[Film made of cycloolefin resin]
In the present invention, a film made of a cycloolefin resin (hereinafter sometimes referred to as a COP film) functions as a protective layer for protecting a polarizing film made of a polyvinyl alcohol resin.

  The cycloolefin-based resin is a thermoplastic resin having a monomer unit made of cycloolefin (cyclic olefin) such as norbornene or a polycyclic norbornene-based monomer, and is also referred to as a thermoplastic cycloolefin-based resin. The cycloolefin-based resin may be a ring-opening polymer of the cycloolefin, a ring-opening copolymer using two or more kinds of the cycloolefin, the ring-opening polymer of the cycloolefin, It may be a hydrogenated product of a ring-opening copolymer using two or more types of cycloolefin, and further, an aromatic compound having a cycloolefin and a polymerizable double bond such as a chain olefin or a vinyl group And a copolymer (addition polymer). Moreover, the polar group may be introduce | transduced into cycloolefin type resin.

  The chain olefin in the case where the COP film is formed using a copolymer (cycloolefin resin) of a cycloolefin and an aromatic compound having a polymerizable double bond such as a chain olefin and / or a vinyl group. Examples thereof include ethylene and propylene. Examples of the aromatic compound having a polymerizable double bond include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. The proportion of monomer units composed of cycloolefin in the copolymer is preferably 50 mol% or less, more preferably about 15 to 50 mol%. In particular, when the cycloolefin-based resin is a ternary copolymer of a cycloolefin, a chain olefin, and an aromatic compound having a polymerizable double bond, the ratio of the monomer unit composed of the cycloolefin is as described above. Thus, the amount can be made relatively small (50 mol% or less). In such a terpolymer, the proportion of monomer units composed of chain olefins is usually in the range of 5 to 80 mol%, and the proportion of monomer units composed of aromatic compounds having a polymerizable double bond is Usually, it is in the range of 5 to 80 mol% (provided that the total amount of the aromatic compound having a cycloolefin, a chain olefin and a polymerizable double bond is 100 mol%).

  Moreover, a commercial item can also be used suitably as cycloolefin type resin. Examples of such commercial products are “TOPAS” produced by TOPAS ADVANCED POLYMERS GmbH in Germany and sold in Japan by Polyplastics Co., Ltd., “Arton” sold by JSR Co., Ltd., and Nippon Zeon Co., Ltd. "ZEONOR" (ZEONOR) and "ZEONEX" (Zeonex), and "Appel" (all are trade names) sold by Mitsui Chemicals, Inc.

  In order to form the cycloolefin-based resin into a film, a known method such as a solvent casting method or a melt extrusion method may be appropriately used. Alternatively, as a film made of cycloolefin resin, for example, “Essina” and “SCA40” sold by Sekisui Chemical Co., Ltd., “Zeonor Film” sold by Nippon Zeon Co., Ltd., and sold by JSR Corporation. Commercially available cycloolefin-based resin films formed in advance, such as “Arton Film” (all of which are trade names), may be used.

  The film made of cycloolefin resin may be uniaxially stretched or biaxially stretched. In the case of uniaxial stretching or biaxial stretching, the stretching ratio is usually in the range of 1.1 to 5 times, and more preferably in the range of 1.1 to 3 times. Since the retardation can be imparted to the COP film by stretching, the COP film can be used as a retardation film. In this case, the in-plane retardation value of the COP film may be appropriately set according to the type of the applied polarizing plate, but is usually preferably 30 nm or more. The upper limit value of the in-plane retardation value is not particularly limited, but for example, about 300 nm is sufficient.

  Although it is preferable that the COP film is thinner, if it is too thin, the strength tends to decrease and the workability tends to be inferior. On the other hand, if it is too thick, transparency tends to decrease or the weight of the polarizing plate tends to increase. is there. Accordingly, the thickness of the COP film is usually preferably in the range of 5 to 200 μm, more preferably in the range of 10 to 150 μm, and still more preferably in the range of 20 to 100 μm.

  The film made of the cycloolefin-based resin is bonded to the polarizing film through an adhesive layer described later (using an adhesive). The COP film is subjected to a surface treatment by treating the surface of the adhesive layer side with an organic solvent in order to improve the adhesiveness. Hereinafter, the surface treatment will be described.

[COP film surface treatment]
Before the COP film is bonded to the polarizing film via the adhesive layer (using the adhesive), the surface of the adhesive layer side is improved in order to improve the adhesive force (affinity) with the adhesive layer. Is treated with an organic solvent. Specifically, the surface treatment is performed by contacting with an organic solvent substantially free of solute. In this specification, the surface treatment in which an organic solvent is brought into contact with the COP film may be referred to as “solvent treatment”.

  In the present specification, “substantially free of solute” means that the solid content in the organic solvent to be contacted is 0.1% or less, and the organic solvent is formed on the surface of the film made of cycloolefin resin. Means that a layer having a component different from that of the cycloolefin-based resin is not formed on the surface of the film after contacting and drying or volatilizing. However, with respect to the solid content contained in the organic solvent, the cycloolefin resin and / or the additive contained in the cycloolefin resin can be dissolved in the organic solvent by repeatedly using the organic solvent. except. In the case of repeatedly using an organic solvent, the contacted (coated) organic solvent is contained in the cycloolefin resin and / or the cycloolefin resin on the COP film surface after drying or volatilization. Additives may remain.

  The organic solvent used for the solvent treatment contains an organic solvent (hereinafter sometimes referred to as “good solvent”) that changes the cycloolefin resin constituting the COP film when it comes into contact with the COP film. Furthermore, the organic solvent used for the solvent treatment is an organic solvent that does not substantially change the cycloolefin resin constituting the COP film when it comes into contact with the COP film (hereinafter sometimes referred to as “poor solvent”). May be contained. In the present invention, “change the cycloolefin resin” means that the shape and appearance of the COP film after contact with the organic solvent as compared to the film made of cycloolefin resin before contact with the organic solvent. (For example, smoothness of the surface, etc.) refers to different states. Accordingly, the surface treatment (solvent treatment) refers to a treatment for bringing the shape and appearance (for example, smoothness of the surface, etc.) of the COP film into a state different from that of the COP film before the treatment by bringing an organic solvent into contact therewith.

  Here, whether a certain organic solvent corresponds to the good solvent or the poor solvent is determined by the following test.

  First, the COP film is appropriately cut, and about 1.0 g is taken and accurately weighed to the third decimal place in grams, and the mass is defined as Fg. In addition, about 99.0 g of organic solvent is taken and weighed accurately to the third decimal place in grams, and the mass is defined as Sg. Next, the COP film weighed in the organic solvent is completely immersed and left at 23 ° C. for 24 hours. And after leaving for 24 hours, it is observed whether there is any change in the shape and appearance of the immersed COP film. In addition, about 10.0 g of the supernatant of the organic solvent in which the COP film has been immersed is taken and accurately weighed to the third decimal place in grams, and the mass is defined as Lg. Next, the organic solvent is evaporated to dryness from the weighed supernatant, and the remaining solid is weighed, and the mass is defined as Rg.

From these masses, the dissolution amount of the COP film is determined. If the COP film is completely dissolved in the organic solvent, the solution becomes about 1.0 wt% “= F (= about 1.0 g) / {F + S (= about 100.0 g)} × 100”. The remaining solid content is about 0.1 g “= L (= about 10.0 g) × F (= about 1.0 g) / {F + S (= about 100.0 g)}”. Therefore, the following formula Solubility (wt%) = [R / {L × F / (F + S)}] × 100
From this, the solubility (% by weight) of the COP film is calculated.

  As a result, if there is no change in the shape and appearance of the COP film after being immersed in an organic solvent for 24 hours and the solubility is less than 1% by weight, a substantial change is made in the cycloolefin resin constituting the COP film. Therefore, the organic solvent is judged to be a poor solvent. In other cases, that is, when the shape and appearance of the COP film change or the solubility is 1% by weight or more, it is determined that the organic solvent is a good solvent (the shape and appearance of the COP film). And the solubility is 1% by weight or more). In the above test, although not dissolved, the state in which the shape and appearance of the COP film are changed include a state in which the COP film swells and does not retain its original shape, and a state in which the COP film whitens.

  Typical results among the above tests conducted on a plurality of organic solvents using a film made of a stretched cycloolefin-based resin (trade name “ZEONOR FILM”, manufactured by Nippon Zeon Co., Ltd.) used in Examples described later as samples. The results are summarized in Table 1 below. In addition, the organic solvent described as “-” in the column of “Solubility” in Table 1 shows the solubility of the COP film only by observing the shape and appearance of the COP film after being immersed in the organic solvent for 24 hours. Is not calculated. From the result of observing the shape and appearance of the COP film, it is estimated that the solubility of the COP film is approximately “0” (less than 1% by weight) for the organic solvent described as “−” in the “solubility” column. The

  From the above results and the present inventor's experience, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane have a COP film solubility of nearly 100% by weight, which makes them good good solvents. being classified. Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and chloroform, aliphatic ethers such as diethyl ether and tetrahydrofuran, and aliphatic hydrocarbons such as pentane, hexane and heptane Although the solubility of the COP film may be 1% by weight or more and less than 1% by weight, since both change the shape and appearance of the COP film, they are classified as good solvents.

  On the other hand, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aliphatic alcohols such as isopropyl alcohol and butyl alcohol, and aliphatic esters such as ethyl acetate, propyl acetate, isopropyl acetate and butyl acetate are used as COP films. Is less than 1% by weight and does not change the shape or appearance of the COP film, so it is classified as a poor solvent.

  Among the organic solvents described above, alicyclic hydrocarbons that dissolve COP films and are classified as good solvents are excessively used on the surface of the cycloolefin-based resin even if the alicyclic hydrocarbons are used alone. It has been found that it is effective to further improve the adhesion to the polarizing film without erosion. Therefore, the organic solvent used for the solvent treatment is more preferably an organic solvent containing alicyclic hydrocarbons. Examples of the alicyclic hydrocarbons include compounds represented by the following chemical formula (I).

(In the formula, m represents an integer of 2 to 6, and R represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms)
Even when the organic solvent used for the solvent treatment contains alicyclic hydrocarbons, the organic solvent is more preferably a mixture of alicyclic hydrocarbons and a poor solvent. The poor solvent mixed with the alicyclic hydrocarbons is preferably an alkyl ester of an organic acid, specifically the aliphatic esters described above, and more preferably an acetate ester.

  When performing the solvent treatment, it is important that the COP film and the organic solvent are brought into contact so that the surface of the COP film is not excessively eroded. In the present invention, the haze value of the COP film after the surface treatment (solvent treatment) is adopted as an index for preventing the surface of the COP film from being excessively eroded. If the erosion of the surface of the COP film proceeds, the optical performance of the COP film will be impaired, although the adhesion to the polarizing film is further improved. Therefore, in the present invention, the haze value of the treated COP film does not exceed 0.5%, more preferably does not exceed 0.3%, and further preferably does not exceed 0.2%. Thus, the COP film is treated with a solvent. The haze value is defined in JIS K 7136: 2000 “Plastics—How to Obtain Haze of Transparent Material” and is a numerical value (%) defined by “(diffuse transmittance / total light transmittance) × 100”. is there.

  Further, when the surface of the COP film is eroded by the solvent treatment, the phase difference of the COP film is canceled and the in-plane retardation value tends to decrease. Therefore, when the cycloolefin resin is stretched and an in-plane retardation value is given to the COP film, the amount of change in the in-plane retardation value of the COP film due to the solvent treatment is excessively increased on the surface of the COP film. It can also be used as an index for preventing erosion. Specifically, when the COP film before the solvent treatment has, for example, an in-plane retardation value of 30 nm or more, the in-plane retardation value after the solvent treatment is 3 nm more than the in-plane retardation value before the solvent treatment. In other words, the amount of decrease in the in-plane retardation value after the solvent treatment relative to the in-plane retardation value before the solvent treatment (in-plane retardation value before the solvent treatment−surface after the solvent treatment) It is preferable to carry out the solvent treatment of the COP film so that the (internal retardation value) is 3 nm or less, more preferably 2.5 nm or less, and further preferably 2 nm or less. When the amount of decrease is larger than 3 nm, when the obtained polarizing plate is applied to a liquid crystal display device, the display characteristics may be adversely affected. When alicyclic hydrocarbons are used alone as the organic solvent for solvent treatment, the amount of decrease in the in-plane retardation value tends to be slightly increased. Therefore, the organic solvent is more preferably a mixture of alicyclic hydrocarbons and a poor solvent.

Plane retardation value of the COP film Re is the COP film refractive index in the in-plane slow axis direction n _x of the refractive index in the in-plane fast axis direction (direction orthogonal with the slow axis and the plane) n _y, and the thickness is d, the following equation _{Re = (n x -n y)} × d
It can be measured using various commercially available phase difference meters.

  The mixing ratio of the good solvent and the poor solvent in the organic solvent may be appropriately set in consideration of the haze value of the COP film after the solvent treatment, the amount of decrease in the in-plane retardation value, and the like.

[Polarizing film made of polyvinyl alcohol resin]
In the present invention, a polarizing film made of a polyvinyl alcohol-based resin (hereinafter may be simply referred to as a polarizing film) is only required to have polarizing performance, and the configuration thereof is not particularly limited. For example, uniaxially stretched polyvinyl It is preferably constituted by adsorbing and orienting a dichroic dye on an alcohol resin. The thickness of the polarizing film as the polarizer layer is preferably 30 μm or less, more preferably 25 μm or less, further preferably 15 μm or less, particularly preferably 10 μm or less, and 7 μm or less. Most preferably it is. In addition, the lower limit value of the thickness of the polarizing film is not particularly limited, but can be set to 2 μm, for example.

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin is suitable. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable with the vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acid, olefin, vinyl ether, unsaturated sulfonic acid, and acrylamide having an ammonium group.

  The saponification degree of the polyvinyl alcohol-based resin is preferably 80 mol% or more, more preferably in the range of 90 to 99.5 mol%, and still more preferably in the range of 94 to 99 mol%. If the saponification degree is less than 80 mol%, the water resistance and heat-and-moisture resistance of the polarizing plate obtained using the polarizing film may be lowered. When the degree of saponification exceeds 99.5 mol%, the dyeing speed when adsorbing and orienting the dichroic dye is slowed, the productivity is lowered, and a polarizing film having sufficient polarization performance cannot be obtained. is there.

The saponification degree is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH ₃ ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by saponification. The degree of saponification (mol%) = {(number of hydroxyl groups) / (number of hydroxyl groups + number of acetate groups)} × 100
Defined by The degree of saponification can be determined according to JIS K 6726: 1994 “Testing method for polyvinyl alcohol”. The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetate groups that inhibit crystallization.

  The polyvinyl alcohol resin may be a modified polyvinyl alcohol resin partially modified. Specific examples of the modification method include olefin modification with ethylene or propylene; acrylic acid, methacrylic acid, and the like. Alternatively, unsaturated carboxylic acid modification with crotonic acid or the like; modification with unsaturated carboxylic acid alkyl ester, acrylamide or the like. The modification rate of the polyvinyl alcohol-based resin is preferably less than 30 mol%, and more preferably less than 10 mol%. When modification exceeding 30 mol% is performed, the dichroic dye tends to be difficult to adsorb and align, and a polarizing film having sufficient polarization performance may not be obtained.

  The average degree of polymerization of the polyvinyl alcohol resin is preferably about 100 to 10000, more preferably 1500 to 8000, and even more preferably 2000 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined according to JIS K 6726: 1994 “Polyvinyl alcohol test method”. When the average degree of polymerization is less than 100, it tends to be difficult to obtain a polarizing film having preferable polarizing performance. When the average degree of polymerization exceeds 10,000, the solubility in a solvent deteriorates, and the polarizing film is formed. Tend to be difficult.

  A commercial item can also be used suitably as a polyvinyl alcohol-type resin. Examples of the commercially available products include “PVA124” and “PVA117” (both saponification degree: 98 to 99 mol%) and “PVA624” (saponification degree: 95 to 96 mol%) sold by Kuraray Co., Ltd. ), “PVA617” (degree of saponification: 94.5 to 95.5 mol%); “N-300” and “NH-18” (both saponification degrees: sold by Nippon Synthetic Chemical Industry Co., Ltd.) 98-99 mol%), "AH-22" (degree of saponification: 97.5-98.5 mol%), "AH-26" (degree of saponification: 97-98.8 mol%); "JC-33" (degree of saponification: 99 mol% or more), "JF-17", "JF-17L" and "JF-20" (all saponification degree: 98) sold by Poval Corporation ˜99 mol%), “JM-26” (degree of saponification: 95) 5-97.5 mol%), "JM-33" (degree of saponification: 93.5-95.5 mol%), "JP-45" (degree of saponification: 86.5-89.5 mol%) (All are trade names) and the like.

  The uniaxially stretched polyvinyl alcohol-based resin may be produced by uniaxially stretching the polyvinyl alcohol-based resin alone. After the polyvinyl alcohol-based resin solution is applied to a substrate and dried, the polyvinyl alcohol The resin may be produced by uniaxially stretching the resin with the base material and removing the base material. When the polyvinyl alcohol resin is uniaxially stretched together with the substrate, a polarizing film having a thickness of 7 μm or less can be easily produced. Examples of the substrate include a polyethylene terephthalate film, a polycarbonate film, a triacetyl cellulose film, a norbornene film, a polyester film, and a polystyrene film.

  The dichroic dye adsorbed and oriented on the polyvinyl alcohol resin is preferably iodine or a dichroic organic dye. Specific examples of the dichroic organic dye include, for example, Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Splat Blue G, Splat Blue GL, Supra orange GL, direct sky blue, direct first orange S, first black and the like. Only one type of dichroic dye may be used, or two or more types may be used in combination.

[Adhesive layer]
In the present invention, the first adhesive layer has a function of bonding the COP film and the polarizing film together. In this invention, a 2nd adhesive bond layer has a function which bonds the said polarizing film and the 2nd protective film mentioned later. The first adhesive layer and the second adhesive layer are formed from a first adhesive composition and a second adhesive composition, respectively. These adhesive compositions may be the same as each other or different from each other. In the following description, when simply referred to as “adhesive composition”, the contents are common to the first adhesive composition and the second adhesive composition unless otherwise specified.

  The adhesive composition is not particularly limited, but is a curable resin composition containing an active energy ray-curable compound, an adhesive in which an adhesive component is dissolved in water, or an adhesive component dispersed in water. An aqueous adhesive composition such as an adhesive may be used. Here, the “active energy ray-curable compound” refers to a compound that can be cured by irradiation with active energy rays. The curable resin composition containing the active energy ray-curable compound does not require a drying step after bonding. Therefore, in the polarizing plate according to the present invention, it is more preferable to use a curable resin composition containing an active energy ray-curable compound.

  The active energy ray-curable compound may be a cationically polymerizable compound or a radically polymerizable compound. Examples of the cationic polymerizable compound include an epoxy compound having at least one epoxy group in the molecule, an oxetane compound having at least one oxetane ring in the molecule, and the like. Examples of the radical polymerizable compound include (meth) acrylic compounds having at least one (meth) acryloyloxy group in the molecule. The “(meth) acryloyloxy group” means that either a methacryloyloxy group or an acryloyloxy group may be used. “(Meth)” such as (meth) acrylate has the same meaning.

  More preferably, the active energy ray-curable compound contains at least an epoxy compound. Thereby, the said adhesive composition shows favorable adhesiveness between the said COP film and the said polarizing film, or between the said polarizing film and a 2nd protective film.

  As an aqueous adhesive composition such as an adhesive in which an adhesive component is dissolved in water or an adhesive in which an adhesive component is dispersed in water, an adhesive using a polyvinyl alcohol resin or a urethane resin as a main component A composition.

  In the case of using a polyvinyl alcohol resin as a main component of the aqueous adhesive composition, the polyvinyl alcohol resin is a partially saponified polyvinyl alcohol resin or a completely saponified polyvinyl alcohol resin, a carboxyl group-modified polyvinyl alcohol, It may be a modified polyvinyl alcohol-based resin such as acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol or the like. When the polyvinyl alcohol-based resin is used as an adhesive component, the adhesive composition is often prepared as an aqueous solution of a polyvinyl alcohol-based resin. As for the ratio of the polyvinyl alcohol-type resin which occupies for an adhesive composition, about 1-10 weight part is preferable normally with respect to 100 weight part of water, and the range of 1-5 weight part is more preferable.

  The adhesive composition containing a polyvinyl alcohol resin as a main component may contain a crosslinking agent as necessary. The cross-linking agent may be a compound having a functional group reactive with a polyvinyl alcohol resin, and a compound conventionally used in a polyvinyl alcohol adhesive can be used without particular limitation. Examples of the compound that can serve as a crosslinking agent include, for example, an isocyanate compound having at least two isocyanato groups (—NCO) in the molecule; an epoxy compound having at least two epoxy groups (crosslinked —O—) in the molecule; Or di-aldehydes; organic titanium compounds; inorganic salts of divalent or trivalent metals such as magnesium, calcium, iron, nickel, zinc and aluminum; metal salts of glyoxylic acid; methylol melamine;

  As long as the thickness of the adhesive layer in the polarizing plate can be bonded to the COP film and the polarizing film, or the polarizing film and the second protective film, it is preferably thinner, but too thin. Adhesion may be insufficient. On the other hand, if it is too thick, the appearance of the polarizing plate may be poor. Therefore, the thickness of the first adhesive layer in the polarizing plate is usually about 0.01 to 5 μm, preferably 3 μm or less, more preferably 2 μm or less, and 1 μm or less. Further preferred. The thickness of the second adhesive layer in the polarizing plate is usually about 0.01 to 5 μm, preferably 3 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less. . The lower limit of the thickness of the adhesive layer is not particularly limited, but is preferably 0.01 μm, for example.

[Protective film]
In this invention, a protective film is a film which consists of transparent resin, a 1st protective film is bonded on the COP film mentioned above, and a 2nd protective film is bonded on the polarizing film mentioned above. These protective films may be the same as each other or different from each other. In the following description, when it is simply referred to as “protective film”, the contents are common to the first protective film and the second protective film unless otherwise specified.

  As the protective film in the present invention, a resin film appropriately composed of a transparent resin widely used as a protective film forming material in this field can be used without particular limitation. Examples of the transparent resin include cellulose acetate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, polyester resin, and the like. Of these transparent resins, cellulose acetate resins and cycloolefin resins are more preferably used.

  The resin film made of the cellulose acetate-based resin is a film made of a cellulose portion or a complete acetate ester, and examples thereof include a triacetyl cellulose film and a diacetyl cellulose film. A commercially available product can be appropriately used as the cellulose acetate-based resin. Examples of the commercially available products include “Fujitac TD80”, “Fujitac TD80UF” and “Fujitac TD80UZ” sold by Fuji Film Co., Ltd., “KC2UA”, “KC8UX2M” and Konica Minolta Opto “KC8UY” (all are trade names) and the like.

  The cycloolefin resin is a thermoplastic resin having a monomer unit composed of cycloolefin (cyclic olefin) such as norbornene or polycyclic norbornene monomer, and is also referred to as a thermoplastic cycloolefin resin. The cycloolefin-based resin may be a ring-opening polymer of the cycloolefin, a ring-opening copolymer using two or more kinds of the cycloolefin, the ring-opening polymer of the cycloolefin, It may be a hydrogenated product of a ring-opening copolymer using two or more types of cycloolefin, and further, an aromatic compound having a cycloolefin and a polymerizable double bond such as a chain olefin or a vinyl group And a copolymer (addition polymer). Moreover, the polar group may be introduce | transduced into cycloolefin type resin.

  As the chain olefin in the case of constituting a protective film using a copolymer (transparent resin) of a cycloolefin and a chain olefin and / or an aromatic compound having a polymerizable double bond such as a vinyl group, For example, ethylene, propylene, etc. are mentioned. Examples of the aromatic compound having a polymerizable double bond include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. The proportion of monomer units composed of cycloolefin in the copolymer is preferably 50 mol% or less, more preferably about 15 to 50 mol%. In particular, when the cycloolefin-based resin is a ternary copolymer of a cycloolefin, a chain olefin, and an aromatic compound having a polymerizable double bond, the ratio of the monomer unit composed of the cycloolefin is as described above. Thus, the amount can be made relatively small (50 mol% or less). In such a terpolymer, the proportion of monomer units composed of chain olefins is usually in the range of 5 to 80 mol%, and the proportion of monomer units composed of aromatic compounds having a polymerizable double bond is Usually, it is in the range of 5 to 80 mol% (provided that the total amount of the aromatic compound having a cycloolefin, a chain olefin and a polymerizable double bond is 100 mol%).

  Moreover, a commercial item can also be used suitably as cycloolefin type resin. Examples of such commercial products are “TOPAS” produced by TOPAS ADVANCED POLYMERS GmbH in Germany and sold in Japan by Polyplastics Co., Ltd., “Arton” sold by JSR Co., Ltd., and Nippon Zeon Co., Ltd. "Zeonor" (ZEONOR) and "ZEONEX" (ZEONEX) sold by the company, "Apel" (all are trade names) sold by Mitsui Chemicals, Inc., and the like.

  In order to form the cycloolefin-based resin into a protective film, a known method such as a solvent casting method or a melt extrusion method may be appropriately used. Alternatively, as a protective film made of cycloolefin resin, for example, “ESCINA” and “SCA40” sold by Sekisui Chemical Co., Ltd., “ZEONOR FILM” sold by Nippon Zeon Co., Ltd., and JSR Corporation. Commercially available products of cycloolefin resin films formed in advance, such as “Arton Film” (all are trade names) sold on the market, may be used.

  The protective film made of a cycloolefin resin may be uniaxially stretched or biaxially stretched. In the case of uniaxial stretching or biaxial stretching, the stretching ratio is usually in the range of 1.1 to 5 times, and more preferably in the range of 1.1 to 3 times.

  The protective film in this invention may be comprised by the single layer, and may be comprised by the multilayer. The protective film composed of multiple layers can be formed, for example, by simultaneously injecting a plurality of transparent resins at the time of injection molding during the production of the protective film. Therefore, there is no adhesive layer or pressure-sensitive adhesive layer between the layers in the protective film. The resins forming the layer may be the same as each other or different from each other.

  In the first protective film, from the liquid crystal compound, the high molecular weight compound of the liquid crystal compound, or the like on the surface opposite to the surface to be bonded to the first adhesive layer described later in the protective film. A coat layer may be formed. The second protective film is subjected to a surface treatment such as an antiglare treatment, a hard coat treatment, an antistatic treatment, or an antireflection treatment on the surface of the protective film opposite to the surface to be bonded to the polarizing film. May be.

  Further, the protective film itself may have various functionalities. Examples of the protective film having functionality include, for example, a retardation film that is stretched in one or more directions and develops a retardation, and separates outgoing light from a light source into transmitted polarized light and reflected polarized light or scattered polarized light. Examples thereof include a brightness enhancement film that can improve the emission efficiency by using retroreflected light from a scattered polarized backlight.

  Although the protective film is preferably thinner, if it is too thin, the strength tends to decrease and the processability tends to be inferior.On the other hand, if it is too thick, the transparency tends to decrease or the weight of the polarizing plate tends to increase. is there. Therefore, the thickness of the protective film is usually preferably in the range of 5 to 100 μm, more preferably in the range of 10 to 80 μm, and still more preferably in the range of 10 to 50 μm.

  As an example of a more preferable configuration of the polarizing plate in the present invention, the surface of the first protective film on the side to be bonded to the first adhesive layer described later in the first protective film is a methacrylic resin. It is the phase difference film which is a layer, and the structure whose 2nd protective film is a phase difference film which consists of olefin resin is mentioned. Moreover, the 1st and 2nd protective film can also be set as the structure described in Unexamined-Japanese-Patent No. 2010-217870. By making the first and second protective films described in the publication, the polarizing plate is less likely to cause local color unevenness even when two retardation films are laminated, When applied to an IPS mode liquid crystal cell, the viewing angle characteristics are excellent.

[Separate film]
The separate film in the present invention is also referred to as a release film and has a function of protecting the second pressure-sensitive adhesive layer, and is peeled from the polarizing plate so that the second pressure-sensitive adhesive layer is exposed when the polarizing plate is used. Is done. As the above-described separate film in the present invention, a resin film appropriately configured with a resin widely used as a material for forming a separate film in this field can be used without any particular limitation. As the resin, the same resin as the first and second protective films described above, for example, cellulose acetate resin, cycloolefin resin, polyolefin resin, acrylic resin, polyimide resin, polycarbonate resin, polyester resin Examples thereof include resins. Among these resins, cellulose acetate resins and cycloolefin resins are more preferably used. Moreover, a commercial item can also be used suitably as a separate film.

  The separate film is preferably thinner, but if it is too thin, the strength tends to decrease and the workability tends to be poor. On the other hand, if it is too thick, the weight of the polarizing plate tends to increase. Therefore, the thickness of the separate film is usually preferably in the range of 5 to 100 μm, more preferably in the range of 10 to 80 μm, and still more preferably in the range of 10 to 50 μm.

[Adhesive layer]
In the present invention, the first adhesive layer is a pressure-sensitive adhesive layer or an adhesive layer having a function of detachably bonding the above-described COP film and the first protective film. In the present invention, the second pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer having a function of detachably bonding the first protective film and the separate film. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are respectively a first pressure-sensitive adhesive composition (hereinafter sometimes simply referred to as a pressure-sensitive adhesive composition) and a second pressure-sensitive adhesive composition. Formed from. These pressure-sensitive adhesive compositions may be the same as each other or different from each other. In the following description, when simply referred to as “pressure-sensitive adhesive composition”, the contents are common to the first adhesive composition and the second pressure-sensitive adhesive composition unless otherwise specified.

  In the case where the first adhesive layer is an adhesive layer, the adhesive composition forming the adhesive layer is the first adhesive composition described above (the COP film and the polarizing film are bonded together). The same composition as the adhesive composition for) can be used.

  Examples of the pressure-sensitive adhesive contained in the pressure-sensitive adhesive composition include pressure-sensitive adhesives based on acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and the like. Among these pressure-sensitive adhesives, pressure-sensitive adhesives based on acrylic polymers and the like are excellent in optical transparency and adhesiveness, maintain appropriate wettability and cohesive force, and have weather resistance and heat resistance. It is more preferable because it does not cause problems related to peeling such as floating and peeling under the conditions of heating and humidification. Examples of the acrylic polymer that is a base polymer include alkyl esters of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as methyl group, ethyl group, and butyl group, and (meth) acrylic acid and (meth) acrylic. An acrylic copolymer having a weight average molecular weight of 100,000 or more, blended with a functional group-containing acrylic monomer composed of hydroxyethyl acid or the like so that the glass transition temperature is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. Polymers are useful.

  In addition to the base polymer as the pressure-sensitive adhesive, the pressure-sensitive adhesive composition usually contains a crosslinking agent that crosslinks the base polymer. The crosslinking agent is not particularly limited as long as it is a compound capable of crosslinking the base polymer. Moreover, when bonding the polarizing plate in this invention to a liquid crystal cell, the silane coupling agent may be mix | blended with the said adhesive composition.

  The pressure-sensitive adhesive layer is prepared by, for example, dissolving or dispersing a pressure-sensitive adhesive composition containing the above base polymer in an organic solvent such as toluene or ethyl acetate, and a 10 to 40% by weight solution (or dispersion) with respect to the whole pressure-sensitive adhesive composition. The liquid (or dispersion) is coated on a suitable protective film and dried to form a pressure-sensitive adhesive layer. Then, the pressure-sensitive adhesive layer is formed on the above-described COP film or the first film. It can form by transferring on a protective film. In addition, the formation method of an adhesive layer is not specifically limited.

  Although the thickness of an adhesive layer should just be determined according to the adhesive force etc., it is the range of 1-50 micrometers normally.

  If necessary, the pressure-sensitive adhesive layer may be blended with fillers made of inorganic powders such as glass fibers, glass beads, resin beads, metal powders, or pigments, colorants, antioxidants, ultraviolet absorbers, etc. It may be. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

[Production method of polarizing plate]
Next, the manufacturing method of the polarizing plate cut by the cutting method concerning this invention is demonstrated. In the following description, a separate film, a second pressure-sensitive adhesive layer, a first protective film, a first adhesive layer, a film made of a cycloolefin resin, a first adhesive layer, a polarizing film, a first A method for producing a polarizing plate obtained by laminating a second adhesive layer and a second protective film in this order will be described as an example.

The polarizing plate can be produced by performing the following steps (i) to (vi).
(i) a surface treatment step (surface treatment) in which an organic solvent substantially free of a solute is brought into contact with the surface of a film made of a cycloolefin resin to carry out surface treatment (solvent treatment)
(ii) a drying step of removing the organic solvent and drying the COP film after the surface treatment step;
(iii) a first bonding step in which the COP film after the drying step is bonded to the polarizing film via the first adhesive layer so that the treated surface becomes a bonding surface;
(iv) a second bonding step in which the first protective film is bonded to the surface on the non-adhesive layer side in the COP film via the first adhesive layer;
(v) a third bonding step in which a second protective film is bonded to the surface of the polarizing film on the non-adhesive layer side via a second adhesive layer;
(vi) A fourth bonding step in which a separate film is bonded to the surface of the first protective film on the non-adhesive layer side through a second pressure-sensitive adhesive layer.

  Therefore, a polarizing plate formed by laminating a film composed of a cycloolefin resin, a first adhesive layer, and a polarizing film in this order can be produced by performing the steps (i) to (iii). . The polarizing plate formed by further laminating the first adhesive layer and the first protective film in this order on the surface of the non-adhesive layer side of the COP film is the above (i) to (iv) It can manufacture by performing a process. In addition, a polarizing plate in which a second adhesive layer and a second protective film are further laminated in this order on the surface of the polarizing film on the non-adhesive layer side is obtained by further performing the step (v). Can be manufactured. Further, the polarizing plate formed by further laminating the second pressure-sensitive adhesive layer and the separate film in this order on the surface of the first protective film on the non-adhesive layer side further performs the step (vi). Can be manufactured.

  In the surface treatment step (i), the surface treatment (solvent treatment) is performed by bringing the above-mentioned organic solvent into contact with the surface of the film made of cycloolefin resin. As a specific method of the surface treatment, a method of applying an organic solvent to the surface of the COP film is preferable. As a coating method, for example, a known method such as a casting method, a Meyer bar coating method, a gravure coating method, a comma coating method, a doctor blade method, a die coating method, a dip coating method, or a spraying method can be employed. Here, the casting method is a method in which an organic solvent is allowed to flow down and spread on the surface of a COP film that is an object to be coated while being moved in a substantially vertical direction, a substantially horizontal direction, or an oblique direction therebetween. It is. The surface to be surface-treated may be one side or both sides of the COP film, but at least the surface to be bonded to the polarizing film is subjected to the surface treatment.

  In the drying step (ii), the organic solvent used for the surface treatment of the COP film is removed and the COP film is dried. Drying may be natural drying or may be performed by heating. When drying by applying heat, it is preferable to dry at a temperature below the glass transition point of the COP film from the viewpoint of preventing deformation of the COP film. The drying step (ii) can also be performed in parallel with the surface treatment step (i). In the method for producing a polarizing plate in the present invention, the drying step (ii) and the surface treatment step (i) are performed in parallel, that is, when the COP film is surface-treated with an organic solvent, It is preferable to perform an operation of removing the solvent and drying the COP film. Specifically, a method of applying an organic solvent while applying air to the application surface of the COP film can be employed.

  In said 1st bonding process (iii), the COP film after a drying process is bonded to a polarizing film through a 1st adhesive bond layer so that the process surface may become a bonding surface. As a pasting method, generally known methods can be adopted. Specifically, for example, using a known method such as a casting method, a Mayer bar coating method, a gravure coating method, a comma coating method, a doctor blade method, a die coating method, a dip coating method, or a spraying method, / Or after apply | coating a 1st adhesive composition to the adhesive surface of a polarizing film, the method of laminating | stacking and bonding both films can be employ | adopted. And after apply | coating a 1st adhesive composition, a COP film and a polarizing film are pinched | interposed on a nip roll etc., applying a pressure, and bonding. Further, after dropping the first adhesive composition between the COP film and the polarizing film, a method of pressing both films with a pair of rolls and the like to uniformly spread the first adhesive composition is adopted, Both films can be bonded together. The material of the roll used in this case is preferably metal or rubber. Further, the rolls may be made of the same material or different materials.

  After laminating the COP film and the polarizing film via the first adhesive composition, if the first adhesive composition contains an aqueous adhesive composition, the The first adhesive composition is cured to form a first adhesive layer. The said drying can be performed by spraying a hot air on a bonding thing, for example. The temperature of the hot air is usually in the range of 40 to 100 ° C, preferably in the range of 60 to 100 ° C. The drying time is usually 20 to 1,200 seconds.

  When the first adhesive composition contains a curable resin composition containing an active energy ray-curable compound after the COP film and the polarizing film are bonded together via the first adhesive composition Irradiates active energy rays to cure the first adhesive composition to form a first adhesive layer. Examples of the active energy rays include ultraviolet rays, electron beams, X-rays, and visible rays, but ultraviolet rays are usually more preferable. What is necessary is just to irradiate an active energy ray with the intensity | strength and quantity required in order to harden an active energy ray hardening compound and to make it a 1st adhesive bond layer.

  The thickness of the 1st adhesive bond layer obtained after hardening is about 0.01-5 micrometers normally. In addition, when the 1st adhesive composition contains the water-based adhesive composition, the thickness of a 1st adhesive bond layer can be 1 micrometer or less. On the other hand, when the first adhesive composition contains a curable resin composition containing an active energy ray-curable compound, the thickness of the first adhesive layer is more preferably 2 μm or less. .

  In the second bonding step (iv), the first protective film is bonded to the surface on the non-adhesive layer side of the COP film via the first adhesive layer. As a pasting method, generally known methods can be adopted. Specifically, for example, a method similar to the method in the first bonding step (iii) can be employed.

  After laminating the COP film and the first protective film via the first adhesive composition, the base polymer contained in the first adhesive composition as a pressure-sensitive adhesive is used as a crosslinking agent. To make a first adhesive layer. As a crosslinking method, generally known methods can be adopted.

  In the third bonding step (v), the second protective film is bonded to the surface of the polarizing film on the non-adhesive layer side via the second adhesive layer. The method similar to the method in said 1st bonding process (iii) can be employ | adopted for the bonding method. More preferably, the third bonding step (v) is performed in parallel with the first bonding step (iii).

  In the fourth bonding step (vi), a separate film is bonded to the surface of the first protective film on the non-adhesive layer side through a second pressure-sensitive adhesive layer. The method similar to the method in said 2nd bonding process (iv) can be employ | adopted for the bonding method.

  The polarizing plate of the present invention comprises at least the steps (i) to (iii), more preferably the steps (i) to (iv), particularly preferably the step (v). Further, it can be produced by further preferably performing the above step (vi), that is, by performing the above steps (i) to (vi).

  Moreover, the polarizing plate in this invention may further bond together a 3rd adhesive layer and a surface protective film in this order on the surface at the side of the non-adhesive layer in a 2nd protective film as needed. The third pressure-sensitive adhesive layer is formed from the same pressure-sensitive adhesive composition as the first and second pressure-sensitive adhesive compositions. The third pressure-sensitive adhesive composition forming the third pressure-sensitive adhesive layer may be the same as or different from the first and second pressure-sensitive adhesive compositions. The surface protective film is formed from the same resin as the separate film. The resin forming the surface protective film may be the same as or different from the resin forming the separate film.

[Cutting equipment]
Next, an example of the configuration of a cutting apparatus that cuts the polarizing plate having the above configuration by the cutting method according to the present invention will be described with reference to FIGS. In addition, the structure of a cutting device should just be a structure which can implement the cutting method which concerns on this invention, Therefore, it is not limited to the following structure.

<Cutter for end face processing>
First, the structure of the end surface processing cutter provided in the cutting apparatus will be described. As shown in FIG. 1, the end surface processing cutter includes a rotating body 10. The rotating body 10 is fixed to the support base 10a, and rotates in one direction with the rotation axis A as an axis (rotation center). The rotating body 10 has an installation surface S perpendicular to the rotation axis A. In addition, although the case where the rotary body 10 is a disk shape is shown in FIG. 1, the shape of the rotary body 10 is not limited to the said shape.

  The diameter of the rotating body 10 of the end surface processing cutter may be, for example, 250 mm, but is not particularly limited. The diameter of the rotating body 10 can be set in the range of 150 mm or more and 600 mm or less, depending on the material constituting the rotating body 10 and the thickness of the polarizing plate to be cut (polarizing plate stack W described later). . In addition, the rotation speed of the rotary body 10 should just be set suitably according to the diameter of the rotary body 10, the hardness of each layer which comprises a polarizing plate, cutting conditions, etc., and is not specifically limited.

  A cutting part 1 a is installed on the installation surface S, and the cutting part 1 a has a cutting blade B. The cutting parts 1b to 1f also have a cutting blade B and are installed on the installation surface S. The cutting part 1a protrudes from the installation surface S and has a rectangular top surface. Further, when the cutting part 1a is viewed from the direction perpendicular to the installation surface S, the cutting part 1a has a rectangular shape. In the cutting part 1a, the cutting blade B is formed at the position of the short side of the top surface. However, the cutting blade B may be formed at the position of the long side of the top surface. Moreover, the top surface of the cutting part 1a is not limited to the said shape. The top surface may have a square shape, other polygonal shapes (for example, a triangular shape), or an arc shape.

  The cutting blade B may be formed on at least one short side of the top surface of the cutting portion 1a, and may be formed on, for example, two short sides of the top surface. The cutting blade B is a blade portion of the cutting portion 1a, and the end face of the polarizing plate is cut at this portion. Since the cutting blade B needs to be in contact with the end face of the polarizing plate, it is provided at a position separated from the installation surface S. The distance between the cutting blade B and the installation surface S is appropriately changed depending on the size of the polarizing plate and the like.

  Here, the short side on the top surface means any one of the short sides (widths) in contact with the long side when the cutting parts 1a to 1f are rectangular. Moreover, the edge part of the cutting blade B means the part which touches a long side among the cutting blades B in case the cutting parts 1a-1f are rectangular shape.

  The cutting portions 1a to 1f are provided on the rotating body 10 at equal intervals, and the distance from the rotation axis A is sequentially shortened with three consecutive pieces (1a to 1c and 1d to 1f) as one set. Are arranged as follows. That is, the cutting part 1b located on the opposite side of the rotating direction of the rotating body 10 with respect to the cutting part 1a has a shorter distance from the rotation axis A than the cutting part 1a. Moreover, the cutting part 1c located on the opposite side of the rotating direction of the rotating body 10 with respect to the cutting part 1b has a shorter distance from the rotation axis A than the cutting part 1b. Thus, the three cutting parts 1a to 1c, which are the first cutting part group, are arranged, and further rotated 180 degrees with respect to the cutting parts 1a to 1c with the position of the rotation axis A as the center of symmetry (point symmetry). )), Another set of cutting parts 1d to 1f as the second cutting part group is arranged. In addition, the cutting portions 1a to 1c (and the cutting portions 1d to 1f) have a larger protruding amount (projecting height) from the installation surface S in that order. With this shape, the cutting portion 1a (and the cutting portion 1d) has the longest distance from the rotation axis A and the smallest protrusion amount from the installation surface S, and the cutting portion 1c (and the cutting portion 1f) has the rotation axis A. From the installation surface S is the shortest and the distance from the installation surface S is the largest.

  When the cutting blade B is viewed from the direction perpendicular to the installation surface S, the cutting portions 1a to 1c are defined with a straight line passing through the end of the cutting blade B on the rotating shaft A side and the rotating shaft A as a reference line. And the direction of each cutting blade B of the cutting parts 1d to 1f is inclined 30 degrees in the rotation direction of the rotating body 10 (the arrow direction in FIG. 1B) (inclination angle θ1 in FIG. 1B). = 30 degrees). In other words, the direction of each long side of the cutting parts 1 a to 1 c and the cutting parts 1 d to 1 f is inclined 30 degrees inward from the rotation direction of the rotating body 10. The inclination angle θ1 is not limited to 30 degrees, and may be performed by the cutting method according to the present invention. For example, the inclination angle θ1 may be in the range of 20 degrees to 35 degrees, and more preferably 25 degrees. As long as it is within the range of 30 degrees or less as described above. If the inclination angle θ1 is within the above range, the cutting blade B can be brought into contact with the polarizing plate at a moderate angle. Therefore, when the end face of the polarizing plate is cut, it is possible to suppress chipping or damage of the end face, that is, occurrence of cracks.

  In addition, each cutting blade B of the cutting parts 1a, 1b, 1d, and 1e is a cutting blade for rough cutting, and is made of polycrystalline diamond. On the other hand, the cutting blades B of the cutting portions 1c and 1f are finishing cutting blades and are made of single crystal diamond. However, the material of the cutting blade B is selected as a preferable form, and is not limited to the material.

  As shown in FIG. 2, the cutting part 1 a is attached to the rotating body 10 via a pedestal 20. The pedestal 20 has a groove portion 22 having a width in which the cutting portion 1a can be accommodated in the side surface portion of the cylindrical body portion 21, and includes a flange portion 23 at the upper end. When the cutting part 1 a is attached, the cutting part 1 a is fitted into the groove part 22 of the pedestal 20 and fixed by the attachment bolt 24.

  The installation surface S of the rotating body 10 is provided with an attachment hole 11 having the same shape as the cross-sectional shape of the body portion 21, and further, an attachment groove 12 is provided so as to bisect the attachment hole 11. And when attaching the cutting part 1a, the trunk | drum 21 of the base 20 which attached the cutting part 1a is engage | inserted in the attachment hole 11 of the rotary body 10. FIG. Then, the pedestal 20 is locked to the peripheral edge of the mounting hole 11 by the flange 23. However, since the pedestal 20 can rotate even when the body portion 21 is fitted in the mounting hole 11, the direction of the cutting portion 1a (cutting blade B) can be arbitrarily adjusted. Then, after determining the direction of the cutting portion 1a (the direction of the cutting blade B), the base 20 is fixed to the rotating body 10 by tightening the mounting groove 12 with the tightening bolt 13, and the cutting portion 1a is fixed. Installation of 1a is completed. The cutting parts 1b to 1f are also attached to the rotating body 10 in the same manner.

  The cutting part 1a and the cutting part 1d, the cutting part 1b and the cutting part 1e, and the cutting part 1c and the cutting part 1f attached in this way have the same shape as each other, and on the vertical installation surface S of the rotating body 10. It is point-symmetric with the position of the rotation axis A as the center of symmetry. Thereby, the balance of the cutter for end surface processing at the time of rotation of the rotary body 10 will be maintained. As long as the balance of the cutter for end face processing during the rotation of the rotating body 10 is maintained in this way, the number of cutting blades is not limited to six, but four, eight, ten or twelve, etc. You may change to The cutting device provided with the end surface processing cutter having the above-described configuration can cut the polarizing plate by the cutting method according to the present invention.

  In addition, the cutter for end surface processing is not limited to the said structure, For example, the protrusion amount of a cutting blade and the distance from a rotating shaft may mutually be the same regarding each cutting blade. Further, the inclination angle of the cutting blade may be different for each cutting blade.

<Cutting device>
As shown in FIG. 3, the cutting apparatus includes two end surface processing cutters 100 having the above-described configuration so that two end surfaces facing each other in the polarizing plate can be simultaneously processed. Therefore, one rotating body 10 of the two end surface processing cutters 100 is arranged so that the cutting blade comes into contact with the end surface of the polarizing plate along the direction from the COP film side to the polarizing film side in FIG. (B) The rotating body 10 rotates in the direction of the arrow, and the other rotating body 10 has various members such as a cutting portion (cutting blade) such as a cutting portion (cutting blade) of the one rotating body 10. It is provided so as to be plane-symmetric with various members, and rotates in the opposite direction to the one rotating body 10.

  Polarized light in which a plurality of polarizing plates are fixed between the two end face processing cutters 100 with the four sides aligned and overlapped so that the stacking direction (direction from the COP film side to the polarizing film side) is the same. A support device 30 that supports the stacked body W is disposed. The pair of end surface processing cutters 100 are arranged to face each other via the support device 30 and rotate so that the end surfaces can be cut according to the size (width) of the polarizing plate stack W. It can move in the axial direction (direction approaching and moving away from the support device 30). Further, the position (height) of the rotating body 10 of the end surface processing cutter 100 is adjusted so that the polarizing plate stack W can pass through the center point (position of the rotation axis A). Thereby, the end face of the polarizing plate stack W can be cut in the vicinity of the central portion in the horizontal direction including the center point of the rotating body 10. And since it cuts in the center part vicinity of the rotary body 10, regardless of the distance from the rotating shaft A, the size of the pitch of the end surface cut by the cutting parts 1a-1f becomes substantially uniform. That is, the difference in size between pitches is reduced. For this reason, in each polarizing plate in polarizing plate stack W, it becomes difficult to produce a difference in the quality of the end face after cutting.

  The support device 30 includes a flat plate-like base (moving device) 31 and a gate-shaped frame 32 erected on the base 31. The base 31 is movable so as to pass between the pair of end surface processing cutters 100. In addition, a table 33 is provided on the base 31 to rotate by placing the polarizing plate stack W, and a cylinder that can be moved up and down and rotated at a position facing the table 33 in the frame 32. 34 is suspended. Therefore, the support device 30 holds the polarizing plate stack W sandwiched between the table 33 and the cylinder 34 via the pair of jigs 35 from above and below, and rotates the polarizing plate stack W according to the cutting process. It is like that. Further, the cutting device is provided with various accessory configurations such as a driving device for driving the end surface processing cutter 100, the rotating body 10, the support device 30, the table 33, the cylinder 34, and a control unit for performing the control. Yes. In addition, illustration of these attached structures is abbreviate | omitted.

<Cutting method>
An example of a method of cutting the end face of the polarizing plate stack W using the cutting apparatus having the above configuration, that is, an example of the cutting method according to the present invention will be described with reference to FIG. In the following description, a method of cutting the end surface of the polarizing plate stack W formed by superposing a plurality of polarizing plates will be described as an example, but the cutting of the end surface is performed on one polarizing plate. You may go.

  The cutting process in the cutting method according to the present invention includes a cutting blade formed on each top surface of the cutting unit by rotating a rotating body including a plurality of cutting units installed on an installation surface perpendicular to the rotation axis. Is a step of cutting the end face by bringing it into contact with the end face of the polarizing plate.

  First, the polarizing plate stack W is placed on a table via a pair of jigs 35 so that the cutting blades are in contact with the end face of the polarizing plate stack W along the direction from the COP film side to the polarizing film side. It is supported by the support device 30 by being sandwiched and held between the cylinder 33 and the cylinder 34 from above and below. Then, the supported polarizing plate stack W is rotated by driving the table 33 so that the end surface thereof faces the end surface processing cutter 100 side. Further, the pair of end surface processing cutters 100 are moved in accordance with the size (width) of the polarizing plate stack W.

  Next, the rotating body 10 of the end surface processing cutter 100 is driven to rotate at a constant speed, and the base plate 31 is moved at a constant speed in a direction in which the polarizing plate stack W approaches the rotating body 10, thereby the polarizing plate stack. Move W to start cutting. That is, in the cutting process, the rotating body 10 is moved relative to the polarizing plate stack W while being rotated along the longitudinal direction of the cutting end face.

  At the time of cutting, first, the cutting portions 1a and 1d located on the outermost side of the rotating body 10 come into contact with the polarizing plate stack W to cut the end surfaces thereof. Next, as the base 31 moves, the cutting parts 1b and 1e provided inside the cutting parts 1a and 1d come into contact with the polarizing plate stack W to cut the end surfaces. At this time, since the cutting portions 1b and 1e have a larger protruding amount than the cutting portions 1a and 1d, the end surfaces cut by the cutting portions 1a and 1d can be further cut. That is, the end surface of the polarizing plate stack W is gradually cut by the cutting portions 1a, 1b, 1d, and 1e that are cutting blades for rough cutting. Finally, the cutting portions 1c and 1f, which are finishing cutting blades, come into contact with the polarizing plate stack W to cut the end surfaces thereof, thereby performing mirror finishing.

  The cutting conditions may be set as appropriate according to the size of the polarizing plate stack W (polarizing plate), the hardness of each layer constituting the polarizing plate, the material and the number of cutting blades B, and the like. However, for example, the following conditions are suitable. Specifically, n sets of cutting part groups (two sets (first and second) cutting part groups in FIG. 1) are formed on the rotator 10, and when the rotator 10 makes one revolution, a polarizing plate stack. Assuming the case where the cutting part group contacts the end face of W n times, the number of contacts between the end face of the polarizing plate stack W and the cutting part group is 500 times or more and 1000 times per 100 mm in the longitudinal direction of the end face. The following range is preferable, and the range of 600 times or more and 800 times or less is more preferable. If the number of contact times exceeds 1000, frictional heat is generated between the end face of the polarizing plate stack W and the cutting portion group (cutting blade), and the end face of the polarizing plate stack W may be seized. . If the number of times of contact is less than 500, the end face of the polarizing plate stack W may not be accurately cut (not in a good finished state).

  Accordingly, the relative moving speed between the polarizing plate stack W and the rotation axis A of the rotating body 10 and the rotating speed of the rotating body 10 may be set as appropriate so that the number of contacts can be satisfied. . Specifically, the relative moving speed is usually in the range of 200 to 2000 mm / min, and more preferably in the range of 500 to 2000 mm / min. When the relative moving speed exceeds 2000 mm / min, there is a risk that the end face of the polarizing plate stack W may not be cut with high precision (not in a good finished state), and there are inconveniences such as cracks and peeling on the end face of the polarizing plate stack W. May occur. When the relative moving speed is less than 200 mm / min, frictional heat is generated between the end face of the polarizing plate stack W and the cutting portion group (cutting blade), and the end face of the polarizing plate stack W is baked. There is a fear. Moreover, the said rotational speed should just normally be the range of 2000-8000 rpm, and the range of 2500-6000 rpm is more preferable. If the rotational speed exceeds 8000 rpm, the end face of the polarizing plate stack W may not be cut with high precision (not in a good finished state), and inconveniences such as cracks and peeling may occur on the end face of the polarizing plate stack W. is there. When the rotational speed is less than 2000 rpm, frictional heat is generated between the end surface of the polarizing plate stack W and the cutting portion group (cutting blade), and the end surface of the polarizing plate stack W may be seized. .

  Moreover, the range of 0.2-0.5 mm is preferable, and the cutting depth (depth which goes to the depth direction of an end surface) cut once by the cutting blade for rough cutting is 0.2-0.3 mm The range of is more preferable. If the cutting depth exceeds 0.5 mm, peeling between the COP film and the polarizing film may not be effectively suppressed during cutting. If the cutting depth is less than 0.2 mm, the end face of the polarizing plate stack W may not be cut accurately (not in a good finished state).

  Furthermore, the total cutting depth (depth toward the depth direction of the end surface) cut by the cutting blade for roughing in the cutting portion group, that is, the thickness of the end surface scraped off in the polarizing plate stack W is 0.2 to The range of 1.5 mm is preferable, and the range of 0.5 to 1.2 mm is more preferable. When the total cutting depth exceeds 1.5 mm, the deterioration due to wear of the cutting blade becomes significant, and the impact applied to the end face of the polarizing plate stack W becomes large. There is a risk of inconvenience such as peeling. If the total cutting depth is less than 0.2 mm, the dimensional accuracy is deteriorated, and the end face of the polarizing plate stack W may not be cut accurately (not in a good finished state).

  Moreover, the cutting depth (depth which goes to the depth direction of an end surface) cut with one finishing cutting blade has the preferable range of 0.01-0.15 mm, and the range of 0.01-0.1 mm. More preferred. If the cutting depth exceeds 0.15 mm, the impact applied to the end face of the polarizing plate stack W increases, and there is a risk that inconveniences such as cracks and peeling occur on the end face of the polarizing plate stack W. In general, it is difficult to perform cutting with an accuracy of less than 0.01 mm.

  In this way, after two end faces facing away from each other in the polarizing plate stack W are simultaneously cut, the polarizing plate stack W is rotated 90 degrees by driving the table 33, and the unprocessed end surface is turned into the end face. The remaining two end faces are simultaneously cut toward the processing cutter 100 in the same manner as the above-described cutting.

  Thereby, all the cutting of the four end surfaces in the polarizing plate stack W is completed, and a plurality of polarizing plates in which the four end surfaces are cut are manufactured. That is, a polarizing plate is manufactured by a manufacturing method including the cutting method. In addition, the cutting waste adhering to the end surface of the polarizing plate stack W can be removed without being scattered by using a so-called adhesive roll or adhesive tape.

  As described above, the cutting method according to the present invention cuts the end face of a polarizing plate formed by laminating a film made of cycloolefin resin, a first adhesive layer, and a polarizing film made of polyvinyl alcohol resin in this order. In the cutting method, the surface of the adhesive layer side of the COP film is treated with an organic solvent, and the cutting blade contacts the direction from the COP film side to the polarizing film side on the end face of the polarizing plate. This is a method of cutting the end face by performing a cutting process.

  Moreover, the manufacturing method which concerns on this invention is a method including the said cutting method. Therefore, the manufacturing method of the polarizing plate which includes the cutting process which employs the cutting method according to the present invention to cut the end face is included in the category of the present invention. Steps other than the cutting step in the production method, for example, a step of laminating a film made of a cycloolefin resin and a first adhesive layer, a step of laminating a first adhesive layer and a polarizing film, etc. Conventional processes can be employed.

  Furthermore, the polarizing plate which concerns on this invention is manufactured with the said manufacturing method. Therefore, the polarizing plate manufactured by the manufacturing method which includes the cutting process which employs the cutting method according to the present invention to cut the end face is included in the category of the present invention.

  Accordingly, it is possible to provide a polarizing plate whose end face is cut with high accuracy without causing peeling between the COP film and the polarizing film.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples. In Examples and Comparative Examples, “parts” and “%” representing the amount used or content are based on weight unless otherwise specified.

[Example 1]
<Preparation of polarizing film>
A 75 μm thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more was immersed in pure water at 30 ° C. for 1 minute. Next, the polyvinyl alcohol film was dyed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.02 / 2/100 at 30 ° C. for 1 minute. Thereafter, the dyed polyvinyl alcohol film was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 12/5/100 at 56.5 ° C. for 5 minutes to perform boric acid treatment. In addition, the polyvinyl alcohol film was stretched mainly in the dyeing and boric acid treatment steps. The overall draw ratio was 5.3 times. Next, the boric acid-treated polyvinyl alcohol film was washed with 8 ° C. pure water and then dried at 65 ° C. for 1 minute. As a result, a polarizing film having a thickness of about 30 μm in which iodine was adsorbed and oriented on polyvinyl alcohol was produced.

<Preparation of adhesive composition>
Acetacetyl group-modified polyvinyl alcohol [trade name: “Gosephimer Z-200”, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., 4% aqueous solution viscosity = 12.4 mPa · sec, saponification degree = 99.1 mol%] An aqueous solution having a concentration of 10% was prepared by dissolving in pure water. This aqueous solution of acetoacetyl group-modified polyvinyl alcohol and sodium glyoxylate as a cross-linking agent are mixed so that the weight ratio of the former: latter solids is 1: 0.1, and further, acetoacetate is added to 100 parts of water. The mixture was diluted with pure water so that the acetyl group-modified polyvinyl alcohol was 2.5 parts to prepare an adhesive composition (first and second adhesive compositions).

<Preparation of film made of cycloolefin resin>
On one side of a COP film (trade name: “ZEONOR FILM”, manufactured by Nippon Zeon Co., Ltd., in-plane retardation value = 90 nm, retardation value in thickness direction = 79 nm) made of stretched cycloolefin-based resin, The organic solvent formed by mixing with toluene: methyl ethyl ketone = 3: 7 (volume ratio) was applied using a coating machine [bar coater manufactured by Daiichi Rika Co., Ltd.]. This coating was performed while applying air to the coated surface with a blower. And the corona treatment was performed to the process surface in the COP film processed with the said organic solvent. This produced the COP film by which the surface of the adhesive layer side was surface-treated.

<Preparation of protective film>
Corona treatment was performed on one side of a (meth) acrylic resin film having a thickness of 40 μm (a (meth) acrylic resin film in which 30% acrylic rubber particles were added to the entire resin composition). Thereby, the 1st protective film was produced.

  One side of a 40 μm-thick cellulose acetate resin film [trade name: “KC4UEW”, manufactured by Konica Minolta Opto Co., Ltd.] was subjected to corona treatment. This produced the 2nd protective film.

<Preparation of polarizing plate>
The adhesive composition was applied to both surfaces of the polarizing film in an atmosphere at 23 ° C. Then, the COP film is bonded to one adhesive composition application surface so that the surface on the surface-treated side becomes a bonding surface, and the other adhesive composition application surface is bonded to the second adhesive composition application surface. The protective film was bonded so that the corona-treated surface was the bonding surface. The above-mentioned pasting was performed using a pasting device ["LPA3301" manufactured by Fuji Pla Co., Ltd.]. The adhesive composition was then dried at 80 ° C. for 5 minutes to form first and second adhesive layers. Thereby, the laminated body formed by laminating | stacking a COP film, a 1st adhesive bond layer, a polarizing film, a 2nd adhesive bond layer, and a 2nd protective film in this order was obtained.

  Next, the corona treatment was performed on the non-adhesive layer side surface of the COP film of the laminate. And the acrylic adhesive sheet | seat of thickness 15 micrometers was bonded together to this surface as a 1st adhesive agent layer. Next, the first protective film was bonded onto the acrylic pressure-sensitive adhesive sheet. Thereby, the first protective film, the first adhesive layer, the COP film, the first adhesive layer, the polarizing film, the second adhesive layer, and the second protective film are laminated in this order. A composite laminate was obtained.

  Furthermore, an acrylic pressure-sensitive adhesive layer having a thickness of 25 μm is provided as a second pressure-sensitive adhesive layer on the first protective film in the composite laminate, and a release treatment is performed on the pressure-sensitive adhesive layer. A separate film (stretched polyethylene terephthalate film) was laminated.

  Moreover, the surface protective film (stretched polyethylene terephthalate film) which has the acrylic adhesive layer as a 3rd adhesive layer was bonded together on the 2nd protective film in the said composite laminated body. Thereby, a separate film, a second pressure-sensitive adhesive layer, a first protective film, a first adhesive layer, a COP film, a first adhesive layer, a polarizing film, a second adhesive layer, a second The large-sized polarizing plate formed by laminating the protective film, the third pressure-sensitive adhesive layer, and the surface protective film in this order was obtained.

  Thereafter, the large polarizing plate was cut into a rectangular shape (cuboid) having a size of 200 mm × 150 mm, and 100 or more polarizing plates before cutting the end face were produced. In the above cutting, the polarizing film was stretched in the direction of 200 mm (so that the direction perpendicular to the direction of stretching was 150 mm).

<Stacking process>
The above-mentioned 100 polarizing plates before cutting the end faces are aligned and fixed so that their lamination directions (directions from the COP film side to the polarizing film side) are the same. Formed.

<Cutting process>
The cutting apparatus shown in FIGS. 1 to 3 except that two cutters each having five cutting parts in the first cutting part group and the second cutting part group are provided facing each other. The cutting process was performed using the same cutting apparatus. Hereinafter, the configuration of the cutting apparatus used in this example will be described with reference to FIGS.

  In the first and second cutting part groups, the five cutting parts are arranged so that the protruding amount of the cutting blade B increases as the cutting part is located further downstream in the rotation direction of the rotating body 10. . Further, the five cutting parts are arranged so that the distance from the rotation axis A to the cutting blade B becomes shorter as the cutting part is located further downstream in the rotation direction of the rotating body 10. The cutting parts constituting the first cutting part group and the second cutting part group are arranged around the rotation axis A and spaced apart from each other at equal intervals. The first cutting portion group is arranged such that two cutting portions having the same protruding amount of the cutting blade B and the distance from the rotating shaft A to the cutting blade B are arranged at positions facing each other via the rotation shaft A. And each cutting part which constitutes the 2nd cutting part group is arranged.

  The polarizing plate stack W was fixed to the cutting apparatus having the above configuration so that the cutting blade of the cutting apparatus entered from the separate film side (direction from the COP film side to the polarizing film side). And the following cutting process (cutting process) was performed about all the four end surfaces. The processing conditions for the four end faces were all the same.

  That is, the polarizing plate stack W is horizontally moved while rotating the rotating body 10 of the two end face processing cutters 100 around the rotation axis A while the position of the rotating body 10 is fixed. The rotating body 10 is moved relative to the polarizing plate stack W in parallel to the length direction of the end surface of the stack W, and the cutting blades B of the respective cutting portions are moved to the COP film on the end surface of the polarizing plate stack W. A cutting process (cutting process) was performed in which the two end surfaces facing each other were brought into contact with each other along the direction from the side toward the polarizing film side, and the end surfaces were simultaneously scraped.

  Specifically, with reference to FIG. 3, the polarizing plate stack W is moved leftward, and the rotation direction of the rotary body 10 of the end surface processing cutter 100 on the back side is changed from the polarizing plate stack W side. The rotation direction of the rotating body 10 of the front end surface processing cutter 100 was counterclockwise when viewed from the polarizing plate stack W side. The relative movement was performed from one end of the end face of the polarizing plate stack W to the other end. With this one relative movement, five stages of cutting are performed on the end face of the polarizing plate stack W by five cutting portions having different projection amounts of the cutting blades B (cutting processes at each stage). Are called the first time, the second time, ...).

  Next, after rotating the polarizing plate stack W by 90 degrees with the rotary table 33, the remaining two end faces were simultaneously subjected to cutting similar to the above-described cutting. Thus, a polarizing plate stack W (100 polarizing plates) in which four end faces were cut was manufactured.

The configuration other than the above-described configuration of the cutting apparatus and various conditions for the cutting process are as follows.
・ Shape of cutting blade B: linear
・ Inclination angle θ1: 30 degrees,
-Rotating speed of rotating body 10: 4800 rpm,
-Relative moving speed between polarizing plate stack W and rotating body 10: 400 mm / min,
-One cutting depth during rough cutting (each cutting depth of the first to fourth cutting operations): 0.24 mm,
-Cutting depth during finishing (cutting depth of the fifth cutting): 0.04 mm,
-Total cutting depth: 1.00 mm.

<Measurement of peeling amount>
With respect to the polarizing plate stack W subjected to the above cutting process, the presence / absence of peeling between the COP film and the polarizing film and the amount of peeling were measured while observing with a microscope. As a result, no peeling was confirmed (peeling amount was 0 μm).

<Tape peeling test>
The separate film of the polarizing plate which performed the said cutting process was peeled off, and after sticking the 2nd adhesive layer of the said polarizing plate on glass, the surface protection film was peeled off. After affixing a tape (Sekisui Chemical Co., Ltd. vinyl cloth tape No. 750 (brown) 50 mm × 50 m) to the corner (corner) of the third pressure-sensitive adhesive layer of this polarizing plate, the tape is applied at once. The tape peeling test which peels was done. And the said tape peeling test was done by 4 corners (four corners) about one polarizing plate, and it implemented by 15 polarizing plates. That is, a tape peeling test was performed on a total of 60 corners, and the number of corners where peeling occurred was measured. As a result, the number of peeled corners was 0 (0/60).

  Therefore, from the measurement of the amount of peeling and the tape peeling test, by performing the cutting method according to the present invention, peeling between the COP film and the polarizing film is recognized at the end face of each polarizing plate during any cutting process. Moreover, it turned out that the end surface of each polarizing plate can be cut collectively by a favorable finishing state. The results are summarized in Table 2.

[Comparative Example 1]
Except that the polarizing plate stack W was fixed so that the cutting blades of the cutting device entered from the surface protective film side (direction from the polarizing film side to the COP film side), the same as the cutting processing of Example 1 The polarizing plate stack W (100 polarizing plates) which cut and processed the four end surfaces was manufactured. And the measurement of peeling amount and the tape peeling test were done. As a result, peeling was confirmed, and the amount of peeling was 131 μm. The number of corners peeled off was 1 (1/60). The results are summarized in Table 2.

[Comparative Example 2]
A polarizing plate was produced by performing the same production method as that of Example 1 except that the surface treatment (solvent treatment) was not performed on the film made of the stretched cycloolefin-based resin. Subsequently, the same stacking process and cutting as the stacking process and cutting of Example 1 were performed, and the polarizing plate stack W (100 polarizing plates) which cut the four end surfaces was manufactured. And the measurement of peeling amount and the tape peeling test were done. As a result, peeling was confirmed, and the peeling amount was 244 μm. The number of corners peeled off was 48 (48/60). The results are summarized in Table 2.

[Comparative Example 3]
Except that the polarizing plate stack W was fixed so that the cutting blade of the cutting device entered from the surface protective film side (direction from the polarizing film side to the COP film side), it was the same as the cutting process of Comparative Example 2. The polarizing plate stack W (100 polarizing plates) which cut and processed the four end surfaces was manufactured. And the measurement of peeling amount and the tape peeling test were done. As a result, peeling was confirmed, and the amount peeled was 189 μm. The number of corners peeled off was 1 (1/60). The results are summarized in Table 2.

  From the results shown in Table 2, in the cutting method (Example 1) in which the cutting blade enters the polarizing plate in the direction from the COP film side to the polarizing film side, that is, the cutting method according to the present invention, no peeling occurs. It turns out that it does not occur. That is, it can be seen that by performing the cutting method according to the present invention, the end faces of the polarizing plates can be cut together in a good finished state.

  In contrast, it can be seen that peeling occurs in the cutting method (Comparative Example 1) in which the cutting blade enters the polarizing plate in the direction from the polarizing film side to the COP film side. Moreover, in the polarizing plates of Comparative Examples 2 and 3 where the surface treatment (solvent treatment) is not performed on the COP film, it can be seen that peeling occurs and the amount of peeling increases. In particular, in the polarizing plate of Comparative Example 2 in which the surface treatment (solvent treatment) is not performed on the COP film, a cutting method in which a cutting blade enters the polarizing plate in the direction from the COP film side to the polarizing film side may be performed. It can be seen that peeling occurs at many corners.

  The cutting method according to the present invention, the polarizing plate manufacturing method including the cutting method, and the polarizing plate can be widely used in the manufacturing field of polarizing plates used in various display devices.

Claims (8)

A cutting method for cutting an end face of a polarizing plate formed by laminating a film made of a cycloolefin-based resin, a first adhesive layer, and a polarizing film made of a polyvinyl alcohol-based resin in this order,
The film made of the cycloolefin-based resin has its surface on the adhesive layer side treated with an organic solvent,
By cutting the end face along the direction from the film side made of cycloolefin resin to the polarizing film side on the end face of the polarizing plate, the end face is cut ,
Using a plurality of cutting blades including at least one rough cutting blade and a finishing cutting blade, the end face of the polarizing plate is cut at least once with the roughing cutting blade, and then finished for cutting. Mirror finish with a blade,
Adjust the depth of one time of cutting with one roughing cutting blade to 0.2 mm to 0.5 mm,
Adjusting the total cutting depth cut by all roughing cutting blades to 0.2 mm to 1.5 mm, and
The cutting method characterized by adjusting the cutting depth cut by one finishing cutting blade to 0.01 mm-0.15 mm .   2. The stacking step of forming a polarizing plate stack by superimposing a plurality of polarizing plates so that their stacking directions are the same before performing the cutting step is performed according to claim 1. Cutting method.   The polarizing plate is a polarizing plate in which the first adhesive layer and the first protective film are further laminated in this order on the surface of the non-adhesive layer side in the film made of cycloolefin resin. The cutting method according to claim 1, wherein:   The polarizing plate is a polarizing plate in which a second adhesive layer and a second protective film are further laminated in this order on the surface of the polarizing film on the non-adhesive layer side. 3. The cutting method according to 3.   The polarizing plate is a polarizing plate in which a second pressure-sensitive adhesive layer and a separate film are further laminated in this order on the surface of the first protective film on the non-adhesive layer side, Item 5. The cutting method according to Item 4.   The cutting step rotates a rotating body including a plurality of cutting parts installed on an installation surface perpendicular to the rotation axis, and the cutting blade formed on each top surface of the cutting part is used as an end face of the polarizing plate. The cutting method according to any one of claims 1 to 5, which is a step of cutting the end face by bringing it into contact.   The cutting method according to claim 6, wherein in the cutting step, the rotating body is moved relative to the polarizing plate while being rotated along the longitudinal direction of the end face being cut.   The manufacturing method of the polarizing plate containing the cutting method of any one of Claim 1 to 7.

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