JP2013200376A - Method for manufacturing end face processed polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an end face processed polarizing plate capable of finishing an end face in a good condition and suppressing the occurrence of crack in a polarizing plate having a film composed of a polypropylene resin laminated on at least one surface via an adhesive.SOLUTION: There is provided a method for manufacturing an end face processed polarizing plate by cutting the end faces of a polarizing plate laminate obtained by laminating a plurality of polarizing plates having a film composed of a polypropylene resin, the method comprising the steps of: by using a cutting rotor having a cylindrical rotor in which the rotational axis extends in a predetermine direction and a plurality of predetermined cutting blades, cutting the end faces by rotating the cutting rotor around the rotational axis so that the cutting blades scrape away the end faces to be cut of the polarizing plate while contacting with the end faces and relatively moving the polarizing plate laminate and the polarizing cutting rotor so that the relative movement speed is 300 mm/min. or more and 1500 mm/min. or less; and cutting the end faces so that the cutting amount of the end faces of a polarizing plate laminate with a rotary cutting blade is 0.2 mm or more and 1.5 mm or less.

Description

  The present invention relates to a method for producing an end-face processed polarizing plate.

  A liquid crystal display device using a liquid crystal display panel as a display element is rapidly expanding its use as a thin display device such as a liquid crystal television, a liquid crystal monitor, and a personal computer. In particular, the market for liquid crystal televisions is remarkably expanding, and with this, there is a strong demand for cost reduction. A liquid crystal display device such as a liquid crystal television is configured by incorporating various members such as a backlight into a liquid crystal panel including a liquid crystal cell and a polarizing plate as constituent members.

  The polarizing plate is usually a transparent protective film, for example, cellulose acetate represented by triacetyl cellulose, with an adhesive layer on one or both sides of a polarizing film made of a polyvinyl alcohol-based resin in which a dichroic dye is adsorbed and oriented. It is the structure which bonded the protective film which consists of a resin. This is bonded to the liquid crystal cell with an adhesive via another optical film as necessary, to obtain a component part of the liquid crystal display device.

  However, when a protective film made of a hydrophilic resin such as cellulose acetate resin is used on both sides of the polarizing plate, it affects the moisture content of the polarizing film made of polyvinyl alcohol resin under high temperature and high humidity conditions. The performance as a board may change somewhat. Therefore, a polarizing plate having a configuration in which a hydrophobic resin, for example, a protective film made of a polypropylene resin, is used instead of the protective film made of a hydrophilic resin and the influence of the environment can be suppressed as much as possible has been studied. For example, Japanese Patent Application Laid-Open No. 2007-334295 (Patent Document 1) discloses that a polarizing film is formed by bonding a protective film made of a polypropylene resin to at least one surface of a polarizing film. Japanese Unexamined Patent Application Publication No. 2009-258588 (Patent Document 2) discloses that a polypropylene resin film serving as a protective film for a polarizing plate is composed of a xylene-soluble component at 20 ° C. of 1% by weight or less. .

  When a polypropylene resin film is used as a protective film for a polarizing plate, low rigidity is pointed out. For example, in Japanese Patent Application Laid-Open No. 2011-197642 (Patent Document 3), assuming that a resin film having low rigidity such as a polypropylene resin film is a protective film on the liquid crystal cell side, an adhesive layer is formed on the surface thereof. A resin film with a pressure-sensitive adhesive layer in which the separate film is formed in this order is prepared in advance, and after the surface activation treatment is performed on the surface of the resin film, the polarizing film is pasted through the adhesive layer, A method of manufacturing is disclosed.

  On the other hand, when a polarizing plate is used in a liquid crystal display device, it is necessary to cut it into a predetermined shape and size, and in order to remove the adhesive sticking out due to pressure during cutting, the polarizing plate is laminated after cutting, and the end face However, in the polarizing plate provided with the above polypropylene-based resin film, due to its low rigidity, appearance defects and cracks often occur after end face cutting.

JP 2007-334295 A JP 2009-258588 A JP 2011-197642 A

  Accordingly, an object of the present invention is to provide a polarizing plate including a film made of a polypropylene resin laminated on at least one surface via an adhesive, and finish the end face in a good state and suppress the occurrence of cracks. An object of the present invention is to provide a method for producing an end-face processed polarizing plate that can be used.

The present invention relates to a polarizing plate laminate in which a polarizing plate comprising a polarizing film comprising a polyvinyl alcohol-based resin and a film comprising a polypropylene-based resin laminated on at least one surface thereof with an adhesive is stacked. A method for manufacturing an end face processed polarizing plate by cutting an end face of a body,
A cylindrical rotator that is parallel to the end surface of the polarizing plate laminate to be cut and has a rotation axis extending in parallel to the thickness direction, and a rotation axis direction of the side surface of the columnar rotator. A cutting rotary body having a plurality of cutting blades,
The polarizing rotating body and the cutting rotating body are rotated by rotating the cutting rotating body around the rotation axis while the cutting blade is in contact with the end face of the polarizing plate stack to be cut off. While relatively moving so that the relative moving speed is 300 mm / min or more and 1500 mm / min or less,
The cutting process is performed so that the cutting amount of the polarizing plate laminate end face by the rotary cutting blade is 0.2 mm or more and 1.5 mm or less,
It is a manufacturing method of an end surface processing polarizing plate.

  Moreover, in the said manufacturing method, the cutting by the relative movement of the said polarizing plate laminated body and the said cutting rotary body is performed in multiple times with respect to each end surface, and the cutting cut by one relative movement is carried out The amount is preferably 0.2 mm or more and 1.0 mm or less.

  Further, in the manufacturing method, the two cutting rotators are respectively disposed on opposite end faces of the polarizing plate laminate, and the facing end faces of the polarizing plate laminate are simultaneously cut by the two cutting rotators. preferable.

  Moreover, in the said manufacturing method, it is preferable to cut while fixing the position of a cutting rotary body and moving a polarizing plate laminated body.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to finish the end surface of a polarizing plate provided with the film which consists of a polypropylene resin laminated | stacked on the at least one surface via the adhesive agent in a favorable state, and can suppress generation | occurrence | production of a crack. The manufacturing method of an end surface processing polarizing plate can be provided.

It is a figure which shows the specific method of the cutting method of this invention. It is a figure (figure seen from the upper part of embodiment of FIG. 1) which shows the specific method of the cutting method of this invention. It is a figure (another embodiment) showing the concrete method of the cutting method of the present invention. It is a figure (another embodiment) showing the concrete method of the cutting method of the present invention.

<Film end face processing method>
A specific embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing an example of an end face processing method of a polarizing plate laminate in the present invention. A laminated body W of polarizing plates provided with a film made of a polypropylene resin laminated on at least one surface of a polarizing film via an adhesive is a rectangular parallelepiped shape obtained by superimposing rectangular films. Thus, the laminated body is sandwiched and fixed.

  The lower presser 21 is provided with a rotary table 31 that rotates about the stacking direction z, and the upper presser 20 is provided with a pusher 30 that rotates in the same direction as the rotary table 31. The table 31 and the pressing tool 30 are rotated in synchronization with each other, and the polarizing plate laminate W can be rotated without shifting up and down.

  FIG. 2 is a view of an example of an end face processing method of the polarizing plate laminate shown in FIG. 1 as viewed from the lamination direction. In the example shown in FIG. 2 (a), a cutting rotator cutting blade including a cylindrical rotator and a plurality of cutting blades arranged along the rotation axis direction of the side surface of the cylindrical rotator is provided. Two cutting rotators 10 and 11 are provided on the end surfaces 41 and 42 facing each other of the polarizing plate laminate, respectively. The columnar rotating body is arranged so that the rotation axis extends in parallel to the thickness direction, parallel to the end face of the polarizing plate laminate W to be cut. The cutting amount can be arbitrarily adjusted by moving the cutting rotators 10 and 11 in the y direction according to the size of the polarizing plate laminate W. In cutting, the rotating rotating bodies 10 and 11 are fixed and rotated around the rotation axis, and the polarizing plate laminate W is passed in the x direction so as to pass between the cutting rotating bodies 10 and 11 facing each other by the processing apparatus. By horizontally moving, the end faces 41 and 42 can be cut simultaneously.

  Further, the other two sides (end surfaces 43 and 44) of the polarizing plate laminate W are subjected to the polarizing plate laminate by the turning table 31 and the pressing tool 32 shown in FIG. 1 after the cutting shown in FIG. The end face can be cut by rotating W by 90 degrees and horizontally moving the polarizing plate laminate W in the x direction as shown in FIG. At this time, the two cutting rotators 10 and 11 may be moved in the y direction and the distance between them may be adjusted according to the amount of cutting.

  The manufacturing method of the end face processed polarizing plate in the present invention is not limited to the method shown in FIG. 1 and FIG. 2, and for example, as shown in FIG. You may cut by moving horizontally along the end surface of a polarizing plate layered body, rotating. In this case, as shown in FIG. 3, if the rotary cutting body is moved leftward along the end faces 41 and 42 of the polarizing plate laminate W while rotating the cutting rotary bodies 10 and 11 about the rotation axis thereof, Also, the other two sides (end surfaces 43 and 44) of the polarizing plate laminate W may be similarly cut by rotating the polarizing plate laminate W by 90 degrees. However, from the viewpoint of drive control of the processing apparatus, a method of performing cutting while fixing the position of the cutting rotator and moving the polarizing plate stack horizontally is preferable.

  Furthermore, in the example shown in FIGS. 1, 2, and 3, the opposing end faces (the end face 41 and the end face 42, or the end face 43 and the end face 44) of the polarizing plate laminate are simultaneously cut by two cutting rotators. The production method of the present invention is not limited to these, and other methods can be used as long as the effects of the present invention are not impaired.

  For example, as shown in FIG. 4, the end surface 41 (or 42) of the polarizing plate stack W is moved by horizontally moving the polarizing plate stack W while fixing and rotating the position of one cutting rotator 10. You may cut. Further, the polarizing plate laminate W is moved horizontally along the end face 41 (or 42) of the polarizing plate laminate W while rotating the one cutting rotator 10 with the polarizing plate laminate W fixed. The end face 41 (or 42) may be cut. In such a case, it is necessary to carry out relative movement between the polarizing plate laminate and the cutting rotator at least four times in order to cut the entire circumference (all end faces) of the polarizing plate laminate. From the viewpoint of performance, it is preferable to use two cutting rotators as shown in FIG.

  In the manufacturing method of the end face processed polarizing plate of the present invention, the relative moving speed of the polarizing plate laminate with respect to the cutting rotating body is 300 mm / min or more and 1500 mm / min or less, preferably 500 mm / min or more and 1000 mm / min or less. . When the cutting speed is less than 300 mm / min, there is a tendency to end-baking due to frictional heat between the polarizing plate laminate and the cutting blade and to fuse between the polarizing plate laminate, while when the cutting speed exceeds 1500 m / min In such a case, the finishing of the end face becomes insufficient, and cracks may occur at the end of the polarizing plate.

  Moreover, in the manufacturing method of this invention, the total cutting amount of each polarizing plate laminated body end surface by a rotary cutting blade is 0.2 mm or more and 1.5 mm or less, Preferably it is 0.5 mm or more and 1.0 mm or less. When the cutting amount is less than 0.2 mm, the cutting accuracy is deteriorated. When the cutting amount is more than 1.5 mm, the impact on the end portion is increased and cracks tend to occur.

  Furthermore, it is preferable that the cutting by the relative movement of the polarizing plate laminate and the cutting rotating body is performed by two or more relative movements with respect to each end face. At this time, the cutting amount cut by one relative movement is preferably 0.2 mm or more and 1.0 mm or less, more preferably 0.2 mm or more and 0.7 mm or less, and further preferably 0.2 mm or more and 0.5 mm or less. It is. By performing the cutting process in such a manner, it is possible to suppress the impact on the end face of the polarizing plate laminate in the cutting process by one relative movement, finish the end face in a better state, and generate cracks. It becomes possible to suppress more. The upper limit of the number of times of relative movement of the cutting rotating body with respect to each end face of the polarizing plate laminate (number of times of cutting) is not particularly limited as long as the total cutting amount satisfies 0.2 mm or more and 1.5 mm or less. From the viewpoint of property, it is preferably 5 times or less, and more preferably 4 times or less.

  Although the rotational speed at the time of cutting of a cutting rotary body is not specifically limited, 2000 rpm or more and 8000 rpm or less are preferable, and 2500 rpm or more and 6000 rpm or less are more preferable. When it is less than 2000 rpm, end baking due to frictional heat between the polarizing plate laminate and the cutting blade may occur, and when it exceeds 8000 rpm, scratches may be generated at the end of the polarizing plate and the appearance may be impaired. In addition, the diameter of a cutting rotary body is about 5-20 cm.

<Polarizing plate>
In the polarizing plate used in the cutting method of the present invention, a film made of a polypropylene resin is laminated on at least one surface of a polarizing film via an adhesive.

(Polarizing film)
Although the polarizing film used for this invention is not specifically limited, Usually, the process of uniaxially stretching a polyvinyl alcohol-type resin film by a well-known method, By dyeing a polyvinyl alcohol-type resin film with a dichroic dye , A process of adsorbing a dichroic dye, a process of treating a polyvinyl alcohol-based resin film adsorbed with a dichroic dye with an aqueous boric acid solution, and a step of washing with water after the treatment with an aqueous boric acid solution. .

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers with other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol resin may be modified, for example, polyvinyl formal and polyvinyl acetal modified with aldehydes can be used. Moreover, the polymerization degree of a polyvinyl alcohol-type resin is about 1,000-10,000 normally, and about 1,500-5,000 are preferable.

  What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of a polarizing film. The method for forming the polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is employed. The film thickness of the polyvinyl alcohol-based raw film can be, for example, about 10 μm to 150 μm.

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing the dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Moreover, you may uniaxially stretch in these several steps.

  In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or may be wet stretching in which stretching is performed in a state where a solvent is used and the polyvinyl alcohol-based resin film is swollen. The draw ratio is usually about 3 to 8 times.

  As a method of dyeing the polyvinyl alcohol resin film with the dichroic dye, for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye is employed. Specifically, iodine or a dichroic dye is used as the dichroic dye. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

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

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually about 1 × 10 ⁻⁴ to 10 parts by weight and preferably about 1 × 10 ⁻³ to 1 part by weight per 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dichroic dye solution used for dyeing is usually about 20 to 80 ° C. Moreover, the immersion time (dyeing time) in this aqueous solution is usually about 10 to 1,800 seconds.

  The boric acid treatment after dyeing with a dichroic dye can usually be performed by immersing the dyed polyvinyl alcohol resin film in a boric acid-containing aqueous solution.

  The amount of boric acid in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight and preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight and preferably about 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, and preferably 50 to 85 ° C.

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

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

  By the drying treatment, the moisture content of the polarizing film is reduced to a practical level. The moisture content is usually 5 to 40% by weight, preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizing film is lost, and the polarizing film may be damaged or broken after drying. Moreover, when a moisture content exceeds 40 weight%, it may be inferior to the thermal stability of a polarizing film.

(Film made of polypropylene resin)
In the polarizing plate used in the present invention, a film made of a polypropylene resin is laminated on at least one surface of a polarizing film via an adhesive.

  The polypropylene resin is not particularly limited, and can be produced by a method of homopolymerizing propylene using a known polymerization catalyst or a method of copolymerizing propylene and ethylene. Further, for example, a solution polymerization method using an inert solvent typified by a hydrocarbon compound such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene or xylene, and a bulk weight using a liquid monomer as a solvent. It can be produced by a combination method, a gas phase polymerization method in which a gaseous monomer is polymerized as it is. Polymerization by these methods may be carried out batchwise or continuously.

  Moreover, a well-known additive may be mix | blended with the polypropylene resin as needed. Examples of additives that can be blended include antioxidants, light stabilizers, ultraviolet absorbers, antistatic agents, lubricants, nucleating agents, antifogging agents, and antiblocking agents. The addition amount is preferably kept in a range that does not adversely affect the optical properties.

  The said polypropylene resin can be shape | molded in the film form by the well-known method used industrially. Specific examples of the film forming method include a melt extrusion molding method using a T die, a compression molding method, and a calendar molding method. Among these, the melt extrusion method using a T die is preferable in terms of productivity and cost.

  A film made of a polypropylene-based resin generally has a low mechanical strength. Therefore, when used as a protective film for a polarizing plate, it is preferable to increase its rigidity. The method for increasing the rigidity is not particularly limited. For example, the polypropylene resin is a propylene homopolymer, or the ethylene unit content in the copolymer of propylene and ethylene is minimized. And the addition of the nucleating agent within a range that does not adversely affect optical properties and film-forming properties.

(Protective film, optical compensation film)
In the polarizing plate used in the present invention, a protective film or an optical compensation film may be laminated on the side of the polarizing film opposite to the side on which the film made of polypropylene resin is laminated. Examples of the protective film or the optical compensation film include transparent films such as a cellulose resin film such as a triacetyl cellulose film (TAC film), an olefin resin film, an acrylic resin film, and a polyester resin film.

(Adhesive layer)
In addition, as described above, the polarizing plate used in the present invention has a film made of polypropylene resin laminated on one side of the polarizing film, and a film made of polypropylene resin of the polarizing film is laminated as necessary. A protective film or an optical compensation film is laminated on the surface opposite to the side. Although it does not specifically limit as an adhesive agent used for lamination | stacking (bonding) of these films, For example, what melt | dissolved in water by using as a main component the composition using a polyvinyl alcohol-type resin or a urethane resin Alternatively, a water-based adhesive dispersed in water or a solventless photocurable adhesive containing a photocurable epoxy resin and a photocationic polymerization initiator may be used. Among these, a solventless photocurable adhesive is preferable from the viewpoint of improving productivity, such as eliminating the need for a step of drying the adhesive. In addition, when bonding a film on both surfaces of a polarizing film, the same kind of adhesive agent may be used and a different kind of adhesive agent may be used, respectively.

(Adhesive layer)
The polarizing plate can be provided with an adhesive layer for bonding the polarizing plate to another member such as a liquid crystal cell. As the pressure-sensitive adhesive used for such a pressure-sensitive adhesive layer, a conventionally known appropriate pressure-sensitive adhesive can be used without particular limitation, and examples thereof include an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive. Among these, an acrylic pressure-sensitive adhesive is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like. The pressure-sensitive adhesive layer can be provided by a method in which such a pressure-sensitive adhesive is used, for example, in the form of an organic solvent solution, which is applied to a base film with a die coater or a gravure coater, and dried. Can be provided also by a method of transferring a sheet-like pressure-sensitive adhesive formed on a plastic film (referred to as a separate film) to the base film. Although there is no restriction | limiting in particular also about the thickness of an adhesive layer, Generally it is preferable to exist in the range of 2-40 micrometers.

(Surface protection film)
Further, a surface protective film (called a protect film) can be further provided on the outermost surface of the polarizing plate for the purpose of preventing damage to the protective film and adhesion of dust. Examples of the constituent material of the surface protective film include polyethylene, polypropylene, polyester, etc. Among them, a stretched film of polyethylene terephthalate is preferable from the viewpoint of moisture permeability and mechanical strength.

  For example, a pressure-sensitive adhesive layer is provided on the surface of the surface protective film, and the surface protective film is laminated on the protective film or the like via the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer applied to the surface protective film is not particularly limited, and an appropriate polymer such as an acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is used as the base polymer. Can be used as The release treatment layer applied to the surface protective film is not particularly limited as long as it has releasability, and may be a type mainly composed of a curable silicone resin, a urethane resin, an epoxy. A modified silicone type obtained by graft polymerization with an organic resin such as a resin or an alkyd resin may be used. Among them, a type mainly composed of a curable silicone resin is preferable. Moreover, it does not specifically limit about formation on a surface protection film, It can carry out by a suitable method.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. In these examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified.

[Production example of polarizing plate for end face processing]
A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% and a thickness of 60 μm was immersed in pure water at 30 ° C., and then the weight ratio of iodine / potassium iodide / water was 0.04 / 1. It was immersed in a 5/100 aqueous solution. Then, it is immersed in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 12 / 3.6 / 100 at 56.5 ° C. for 130 seconds, and further, potassium iodide / boric acid / water has a weight ratio of 12 / 3.6. It was immersed in a 1.5 / 100 aqueous solution at 30 ° C. for 60 seconds. Subsequently, it was washed with pure water at 10 ° C. and then dried in a drying furnace at 60 ° C. and 85 ° C. for a total of 160 seconds to obtain a polarizing film having a thickness of 23 μm in which iodine was adsorbed and oriented on polyvinyl alcohol.

  On one side of the polarizing film obtained as described above, a film (thickness 75 μm) made of a polypropylene resin of a propylene / ethylene random copolymer having an ethylene unit content of 0.4% is used. On the side opposite to the side on which the film made of polypropylene resin is laminated, an optical compensation film made of stretched norbornene resin having a thickness of 50 μm is subjected to corona treatment on the bonding surface, and then a photocurable adhesive. To obtain a polarizing plate.

  In addition, the tensile elasticity modulus in 23 degreeC of the film which consists of said polypropylene resin was 1200 Mpa. The tensile elastic modulus was determined using an autograph “AG-1” manufactured by Shimadzu Corporation. The measurement was performed by cutting a film made of polypropylene resin into a test piece of 20 mm × 100 mm, holding both ends of the short side of the test piece with a chuck, and pulling it at a speed of 5 mm / min.

  Next, a protective film having a pressure-sensitive adhesive layer is formed on the outer surface of the obtained polarizing plate made of polypropylene resin, and an acrylic pressure-sensitive adhesive layer having a thickness of 20 μm is formed on the outer surface of the optical compensation film made of stretched norbornene-based resin. Further, a separate film having been subjected to a release treatment was bonded to the outer surface of the pressure-sensitive adhesive layer to obtain a polarizing plate with a pressure-sensitive adhesive.

  The polarizing plate with the pressure-sensitive adhesive thus obtained was cut into a size of 943 mm × 532 mm to obtain a polarizing plate for cutting.

<Example 1>
400 polarizing plates for cutting obtained in the above production example were laminated, and the end surfaces were cut by the processing methods shown in FIGS. 1 and 2A and 2B. That is, with the positions of the cutting rotators 10 and 11 fixed, the cutting rotator 10 is rotated counterclockwise and the cutting rotator 11 is rotated clockwise around the rotation axis. The polarizing plate laminate was moved in the x direction (left arrow direction in FIG. 2) to cut the end face. Further, the moving speed of the polarizing plate laminate relative to the cutting rotator is 500 mm / min, the rotating speed of the cutting rotator is 5000 rpm, the cutting amount to each end face of the polarizing plate laminate is 1.0 mm, and the number of times of cutting is one time. It was. A crack test was performed on the obtained polarizing plate (one of the polarizing plate laminates) by the following method.

<Crack test>
The polarizing plate that has been subjected to end face cutting is cut into MD 60 mm × TD 80 mm so as to have the cut end face, the separate film is peeled off, and the polarizing plate is attached to a glass plate via an adhesive layer. Combined. Further, the protective film bonded to the outer surface of the polarizing plate was peeled off to prepare a test sample.

  Next, the test sample was placed in an 80 ° C. oven for 1 hour, then taken out and immersed in a 23 ° C. water bath for 30 minutes. Then, after taking out quickly and wiping off the adhering water | moisture content, the end surface of the polarizing plate cut visually with the loupe in the state irradiated with the fluorescent lamp was observed, and the crack generation state was evaluated. The evaluation was performed in the following four stages based on the number of cracks generated, and Lv2 or less was determined to be good. The evaluation results are shown in Table 1.

Lv. 1: Less than 10 cracks generated.
Lv. 2: The number of crack occurrences is 10 or more and less than 30.

Lv. 3: The number of cracks generated is 30 or more and less than 100.
Lv. 4: 100 or more cracks were generated.

<Example 2>
End face processing was performed in the same manner as in Example 1 except that the moving speed of the polarizing plate laminate with respect to the cutting rotator was set to 300 mm / min. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Example 3>
End face processing was performed in the same manner as in Example 1 except that the moving speed of the polarizing plate laminate with respect to the cutting rotator was 1500 mm / min. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Example 4>
End face processing was performed in the same manner as in Example 1 except that the cutting amount of each end face of the polarizing plate laminate by the cutting rotator was 1.5 mm. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Example 5>
In Example 1, the number of times of cutting each end face of the polarizing plate laminate by the cutting rotator was 3 times, each cutting amount was 0.4 mm / 0.4 mm / 0.2 mm, and the total cutting amount was 1.0 mm. Except for the above, end face processing was performed in the same manner as in Example 1. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Example 6>
In Example 1, the number of times of cutting each end face of the polarizing plate laminate by the cutting rotator was 4 times, each cutting amount was 0.25 mm / 0.25 mm / 0.25 mm / 0.25 mm, and the total cutting amount was 1 The end face was processed in the same manner as in Example 1 except that the thickness was set to 0.0 mm. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Comparative Example 1>
In Example 1, end face processing was performed in the same manner as in Example 1 except that the moving speed of the polarizing plate laminate with respect to the cutting rotator was 2000 mm / min. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

<Comparative example 2>
In Example 1, the number of times of cutting each end face of the polarizing plate laminate by the cutting rotator was 3 times, each cutting amount was 1.0 mm / 0.6 mm / 0.4 mm, and the total cutting amount was 2.0 mm. Except for the above, end face processing was performed in the same manner as in Example 1. A crack test was performed on the obtained polarizing plate in the same manner as in Example 1. The evaluation results are shown in Table 1.

  As can be seen from the results in Table 1, in the cutting method according to the present invention, the end face state after cutting was good, and the occurrence of cracks in the crack test was small. Moreover, by performing cutting to each end face of the polarizing plate laminate by a cutting rotator a plurality of times, the generation of cracks was less, and in Example 6 where cutting was performed a total of four times, no cracks were generated. On the other hand, in Comparative Example 1 in which the moving speed of the polarizing plate laminate relative to the cutting rotator is 2000 mm / min and Comparative Example 2 in which the total cutting amount is 2.0 mm, scratches are generated on the end surfaces after cutting. At the same time, many cracks occurred in the crack test.

10, 11 Cutting rotator 20 Upper presser 21 Lower presser 30 Presser 31 Rotating table 41, 42, 43, 44 End face of polarizing plate laminate W Polarizing plate laminate

Claims (4)

A polarizing plate comprising a polarizing film made of a polyvinyl alcohol-based resin and a film made of a polypropylene-based resin laminated on at least one surface of the polarizing plate with an adhesive is provided with an end face of a polarizing plate laminate in which a plurality of the polarizing plates are stacked. It is a method of cutting and manufacturing an end face processed polarizing plate,
A cylindrical rotator that is parallel to the end surface of the polarizing plate laminate to be cut and has a rotation axis extending in parallel to the thickness direction, and a rotation axis direction of the side surface of the columnar rotator. A cutting rotary body having a plurality of cutting blades,
The polarizing rotating body and the cutting rotating body are rotated by rotating the cutting rotating body around the rotation axis while the cutting blade is in contact with the end face of the polarizing plate stack to be cut off. While relatively moving so that the relative moving speed is 300 mm / min or more and 1500 mm / min or less,
The cutting process is performed so that the cutting amount of the polarizing plate laminate end face by the rotary cutting blade is 0.2 mm or more and 1.5 mm or less,
Manufacturing method of end surface processed polarizing plate.   Cutting by relative movement between the polarizing plate laminate and the cutting rotating body is performed a plurality of times on each end face, and the cutting amount cut by one relative movement is 0.2 mm or more. The manufacturing method of the end surface processed polarizing plate of Claim 1 which is 0 mm or less. The two cutting rotators are respectively disposed on opposite end surfaces of the polarizing plate laminate, and the two opposing end surfaces of the polarizing plate laminate are simultaneously cut by the two cutting rotators.
The manufacturing method of the end surface processed polarizing plate of Claim 1 or 2.   The manufacturing method of the end surface processing polarizing plate in any one of Claims 1-3 which fixes the position of a cutting rotary body, and performs cutting while moving a polarizing plate laminated body.

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