JP2011242578A - Set of roll-like polarizing plates, manufacturing method thereof, and manufacturing method of liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a set of roll-like polarizing plates, which is composed of a long polarizing plate formed in a back-and-face asymmetrical manner, capable of being stuck to a liquid crystal cell with high axis precision while restraining a curl or the like of the polarizing plate, to provide a manufacturing method of the set of roll-like polarizing plates, and to provide a manufacturing method of a liquid crystal panel using the set of roll-like polarizing plates.SOLUTION: A set of roll-like polarizing plates includes: a first roll-like polarizing plate formed from a long polarizing plate in which a protective film, a first polarizing film, a biaxial retardation film, a first adhesive layer, and a first release film are laminated in that order; and a second-roll-like polarizing plate formed from a long polarizing plate in which an anti-glare film, a second polarizing film, a second adhesive layer, and a second release film are laminated in that order. An absorption axis of the polarizing film is parallel to a lengthwise direction of the long polarizing plate, and the set of roll-like polarizing plate is wound into a roll so as to have a dimension corresponding to a long side or a short side of a liquid crystal cell. A manufacturing method of the set of roll-like polarizing plates and a manufacturing method of the liquid crystal panel using the set of roll-like polarizing plates are also provided.

Description

  The present invention corresponds to the first roll-shaped polarizing plate having a width corresponding to the long side of the liquid crystal cell for bonding to the back side of the liquid crystal cell and the short side of the liquid crystal cell for bonding to the viewing side. Of a roll-shaped polarizing plate comprising a second roll-shaped polarizing plate having a width to be manufactured, a method for producing a set of roll-shaped polarizing plates suitable for the production thereof, and production of a liquid crystal panel using the set of roll-shaped polarizing plates Regarding the method.

  The polarizing plate is useful as a constituent member of a liquid crystal display device, and the demand for the polarizing plate is rapidly increasing with the spread of the liquid crystal display device. With the application of a liquid crystal display device to a large-sized television or the like, the polarizing plate is also required to be thinner and cheaper while maintaining or improving its performance.

  Traditionally, a polarizing plate has a structure in which a transparent protective film is bonded to at least one side, usually both sides, of a polarizing film made of a polyvinyl alcohol resin on which a dichroic dye is adsorbed and oriented. Conventionally, a film of a cellulose acetate resin typified by triacetyl cellulose has been frequently used as a protective film for a polarizing plate, and the thickness thereof is usually about 40 to 120 μm. For bonding such a cellulose acetate resin film to a polarizing film, an adhesive composed of an aqueous solution of a polyvinyl alcohol resin is often used. However, when a polarizing film made of polyvinyl alcohol resin is laminated with a protective film made of cellulose acetate resin via an adhesive made of an aqueous solution of polyvinyl alcohol resin, the polarizing plate is used for a long time under wet heat conditions. Further, there are problems that the polarization performance is deteriorated and the protective film is peeled off from the polarizing film.

  Therefore, there is an attempt to configure at least one of the protective films bonded to both surfaces of the polarizing film with a resin other than the cellulose acetate resin. For example, in JP-A-8-43812 (Patent Document 1), in a polarizing plate in which a protective film is laminated on both sides of a polarizing film, at least one of the protective films is a thermoplastic having the function of a retardation film. It is described that it is composed of a norbornene resin. Japanese Patent Laid-Open No. 2002-174729 (Patent Document 2) includes an amorphous polyolefin resin on one surface of a polarizing film made of a polyvinyl alcohol resin on which iodine or a dichroic dye is adsorbed and oriented. A polarizing plate is described in which a protective film is bonded and a protective film made of a resin different from an amorphous polyolefin-based resin, such as a cellulose acetate-based resin, is bonded to the other surface of the polarizing film. As amorphous polyolefin resin, amorphous cyclic polyolefin resin, also called alicyclic polyolefin or norbornene resin, is relatively excellent in heat resistance and moisture resistance, excellent in transparency, and retardation It is widely used for reasons such as the ability to adjust values relatively easily.

  On the other hand, JP 2007-334295 A (Patent Document 3) describes a polarizing plate in which a protective film is bonded to both surfaces of a polarizing film, and at least one of the protective films is made of a polypropylene resin. Yes. Polypropylene-based resin films that have been widely used in general industrial fields have a small dimensional change in a moist heat environment, low moisture permeability, excellent resistance to organic solvents, and are available at low cost. It is effective as a protective film.

  Cyclic polyolefin resins such as norbornene resins or chain polyolefin resins such as polypropylene resins give a suitable retardation value by stretching uniaxially or biaxially. It is suitable for angle compensation and phase difference compensation. Therefore, a polarizing plate in which a cyclic or linear polyolefin resin film stretched on one side of a polarizing film is bonded, and a protective film made of a transparent resin such as triacetyl cellulose is bonded on the other side of the polarizing film. Are combined with a liquid crystal cell on the stretched film side to have an optical compensation function.

  JP-A-10-186133 (Patent Document 4) is provided with a protective film made of a transparent synthetic resin on one side of a polyvinyl alcohol polarizing film, and directly on the other side without a protective film. A polarizing plate provided with is described. According to such a structure, since one protective film can be reduced, the polarizing plate can be further thinned, which is advantageous in terms of cost.

  By the way, in an optical member manufacturer, it is common to continuously produce a long optical film having an optical function such as a polarizing plate used in a liquid crystal display device, or a laminate thereof while winding it into a roll. is there. The polarizing plate manufactured in this way is delivered to a liquid crystal panel processing manufacturer, and bonded to a liquid crystal cell in the liquid crystal panel processing manufacturer to manufacture a liquid crystal panel. Conventionally, when optical component manufacturers deliver optical components such as polarizing plates to a liquid crystal panel processing manufacturer, a long optical sheet punched into a predetermined size desired by the liquid crystal panel processing manufacturer (optical) Sheet) was inspected, and several sheets were stacked and packed.

  As described above, when an optical member manufacturer packs a plurality of optical sheets obtained by punching into a predetermined size, a working environment with a high degree of cleanliness is required so as not to generate dust and dirt. ing. In addition, packing materials are specially selected and packing work needs to be performed carefully so that scratches and cracks do not occur during transportation. On the other hand, liquid crystal panel processing manufacturers use optical sheets that are tightly packed for assembly processing, but the packaging is severe, so the work of unpacking is difficult, and the work of unpacking is subject to scratches and cracks. It must be done with great care so as not to occur, and the work is complicated and productivity is lowered, and the burden on the operator is large. Moreover, since inspection is usually performed many times before packing, after unpacking, and after bonding a liquid crystal panel member, there is a problem of over-inspection.

  As means for solving this, Japanese Patent Application Laid-Open No. 2009-276751 (Patent Document 5) uses a roll original fabric set composed of two rolls including an optical film including a polarizing plate, and these rolls have a predetermined length. In this method, a method of bonding to an optical display unit (liquid crystal cell) so that the absorption axes of the respective polarizing plates are orthogonal to each other is disclosed. According to this method, the axial accuracy of the bonding is improved, Further, it is said that defects due to contamination in the apparatus are less likely to occur. However, in this document, it is clear that what material and characteristics are suitable as a roll stock set that improves the axial accuracy of bonding and does not easily cause defects due to contamination in the apparatus. Is not considered.

JP-A-8-43812 JP 2002-174729 A JP 2007-334295 A Japanese Patent Laid-Open No. 10-186133 JP 2009-276751 A

  As described above, for the purpose of further reducing the price and thickness, or improving the durability of the polarizing plate, the protective film disposed on both surfaces of the polarizing film may be made of different materials, In many cases, the protective film is bonded only to the film, or the film is asymmetrical with respect to the polarizing film. The polarizing plates that the inventors have studied for the above-mentioned purposes are also often asymmetrical polarizing plates. Such a polarizing plate is likely to curl when it is punched into a single sheet, and when the polarizing plate of a single sheet is bonded to a liquid crystal cell via an adhesive layer, a bubble is bitten at the edge or center. It tends to cause problems such as Moreover, in the case of a single-sheet polarizing plate, curling may increase with changes in the moisture content in the polarizing film, which makes it more difficult to bond to the liquid crystal cell.

  Therefore, one of the objects of the present invention is a set of roll-shaped polarizing plates composed of two roll-shaped polarizing plates for bonding to both surfaces of a liquid crystal cell, which are composed of long and asymmetric long polarizing plates. It can be used for the manufacturing process of the liquid crystal panel without cutting out into single wafers, and it is good while effectively suppressing curling of the polarizing plate and the entrapment of bubbles and foreign substances during polarizing plate bonding. It is providing the set of a roll-shaped polarizing plate which can be bonded to a liquid crystal cell with a sufficient axial accuracy, and its manufacturing method. Another object of the present invention is a method of manufacturing a liquid crystal panel using a set of roll-shaped polarizing plates composed of the above-described asymmetric long polarizing plates, and includes curling of polarizing plates and accompanying polarization It is to provide an efficient manufacturing method of a liquid crystal panel capable of being bonded to a liquid crystal cell with good axial accuracy while effectively suppressing air bubbles and foreign matter biting during plate bonding.

The present invention includes a protective film made of a transparent resin, a first polarizing film made of a polyvinyl alcohol resin, an in-plane retardation value R ₀ in the range of 30 to 200 nm, and a thickness direction retardation value R _th of 100. It is in a range of ˜350 nm, and is composed of a long polarizing plate in which a biaxial retardation film made of a polyolefin resin, a first pressure-sensitive adhesive layer, and a first release film are laminated in this order. The back surface of the liquid crystal cell is wound in a roll shape with the absorption axis of the first polarizing film being parallel to the long side direction of the long polarizing plate and having a width corresponding to the long side of the liquid crystal cell. A first roll-shaped polarizing plate for bonding to the side;
An antiglare film having a haze value in the range of 0.1 to 45%, a second polarizing film made of a polyvinyl alcohol-based resin, a second pressure-sensitive adhesive layer, and a second release film in this order. A state in which a long polarizing plate is formed and the absorption axis of the second polarizing film is parallel to the long side direction of the long polarizing plate and has a width corresponding to the short side of the liquid crystal cell A second roll-shaped polarizing plate, which is wound in a roll shape, for bonding to the viewing side of the liquid crystal cell,
A set of roll-shaped polarizing plates is provided.

Here, the second roll-shaped polarizing plate has a haze value of 0.5% or less between the second polarizing film made of polyvinyl alcohol-based resin and the second pressure-sensitive adhesive layer, and has an in-plane position. You may have the non-orientation film which consists of polyolefin resin whose phase difference value _R0 is less than 30 nm.

Moreover, this invention is a roll-shaped polarizing plate which consists of the 1st roll-shaped polarizing plate for bonding to the back side of a liquid crystal cell, and the 2nd roll-shaped polarizing plate for bonding to the visual recognition side of a liquid crystal cell. A method of manufacturing a set of is provided. The method for producing a set of roll-shaped polarizing plates of the present invention includes a protective film made of a transparent resin, a first polarizing film made of a polyvinyl alcohol resin, and an in-plane retardation value R ₀ in the range of 30 to 200 nm. , in the range thickness direction retardation R _th is 100 to 350 nm, and the biaxial retardation film made of a polyolefin resin, a first adhesive layer, a first release film in this order, and In the first original fabric production process and the first original fabric production process in which the first polarizing film is laminated so that the absorption axis of the first polarizing film is parallel to the long side direction to produce the first polarizing plate long original fabric A first slit step of cutting the obtained first polarizing plate long original fabric so as to have a width corresponding to the long side of the liquid crystal cell, and winding the long polarizing plate obtained in the first slit step in a roll shape A first polarizing plate winding step to take Roll polarizing plate manufacturing process; and an antiglare film having a haze value in the range of 0.1 to 45%, a second polarizing film made of a polyvinyl alcohol-based resin, a second pressure-sensitive adhesive layer, and a second The second original film is prepared by stacking the release films of the second polarizing film in this order and with the absorption axis of the second polarizing film being parallel to the long side direction. And a second slit step of cutting the second polarizing plate long original fabric obtained in the second raw fabric preparation step so as to have a width corresponding to the short side of the liquid crystal cell, and the second slit step. And a second polarizing plate manufacturing step including a second polarizing plate winding step of winding the long polarizing plate into a roll shape.

  Furthermore, this invention provides the method of bonding a 1st polarizing plate to the back side of a liquid crystal cell, and bonding a 2nd polarizing plate to the visual recognition side of a liquid crystal cell, and manufacturing a liquid crystal panel. The manufacturing method of the liquid crystal panel of the present invention includes a first transporting step of a liquid crystal cell for transporting the liquid crystal cell so that the short side direction is the flow direction; a first polarizing plate comprising the following steps (A) to (D) Supply bonding process; 2nd conveyance process of the liquid crystal cell which conveys a liquid crystal cell so that the long side direction turns into a flow direction; and the 2nd polarizing plate supply bonding provided with following process (E)-(H). Including a process.

(A) Of the set of roll-shaped polarizing plates, a long polarizing plate is unwound from the first roll-shaped polarizing plate so as to face the back side of the liquid crystal cell supplied in the first transporting step of the liquid crystal cell. First polarizing plate unwinding step,
(B) a first polarizing plate cutting step of cutting the long polarizing plate after being unwound in the first polarizing plate unwinding step into a length corresponding to the short side of the liquid crystal cell;
(C) Pasting of the long polarizing plate unwound in the first polarizing plate unwinding step or the polarizing plate cut in the first polarizing plate cutting step to be conveyed in the first conveying step of the liquid crystal cell A first polarizing plate alignment step to match the position to be combined,
(D) 1st polarizing plate sticking which bonds the long polarizing plate after passing through the 1st polarizing plate alignment process, or the cut polarizing plate to the back side of the liquid crystal cell conveyed at the 1st conveyance process of a liquid crystal cell. Joint process.

(E) Of the set of roll-shaped polarizing plates, a long polarizing plate is unwound from the second roll-shaped polarizing plate so as to be directed to the viewing side of the liquid crystal cell conveyed in the second conveying step of the liquid crystal cell. Second polarizing plate unwinding step,
(F) a second polarizing plate cutting step of cutting the long polarizing plate after being unwound in the second polarizing plate unwinding step into a length corresponding to the long side of the liquid crystal cell;
(G) Pasting of the long polarizing plate unwound in the second polarizing plate unwinding step or the polarizing plate cut in the second polarizing plate cutting step to be transported in the second transport step of the liquid crystal cell A second polarizing plate alignment step to match the position to be combined,
(H) 2nd polarizing plate sticking which bonds the elongate polarizing plate after passing through the 2nd polarizing plate alignment process, or the cut polarizing plate to the visual recognition side of the liquid crystal cell conveyed at the 2nd conveyance process of a liquid crystal cell. Joint process.

  Here, in a 1st polarizing plate supply bonding process, a 1st polarizing plate unwinding process is performed first, after that, a 1st polarizing plate cutting process, a 1st polarizing plate alignment process, and a 1st polarizing plate sticking The order of the combining steps, or the order of the first polarizing plate alignment step, the first polarizing plate cutting step, and the first polarizing plate bonding step, or the first polarizing plate alignment step, the first polarizing plate bonding step. , And the first polarizing plate cutting step. Moreover, in a 2nd polarizing plate supply bonding process, a 2nd polarizing plate unwinding process is performed first, Then, a 2nd polarizing plate cutting process, a 2nd polarizing plate alignment process, and a 2nd polarizing plate bonding The order of the steps, or the order of the second polarizing plate positioning step, the second polarizing plate cutting step, and the second polarizing plate pasting step, or the second polarizing plate positioning step, the second polarizing plate pasting step, And the second polarizing plate cutting step.

  In the manufacturing method of the liquid crystal panel, the first polarizing plate unwinding step and the second polarizing plate unwinding step are long polarizing plates unwound from the first roll-shaped polarizing plate in the first polarizing plate unwinding step. And the flow direction of the long polarizing plate unwound from the second roll-shaped polarizing plate in the second polarizing plate unwinding step can be performed orthogonally. The liquid crystal cell used in the present invention is preferably a VA mode liquid crystal cell.

  According to the present invention, despite the use of a polarizing plate that is asymmetrical on the front and back sides, it is possible to effectively suppress curling of the polarizing plate and the entrainment of bubbles and foreign matters during the bonding of the polarizing plate. A liquid crystal panel in which a predetermined polarizing plate is bonded to both surfaces of a liquid crystal cell with high accuracy can be efficiently produced. In addition, according to the present invention, it is possible to provide a liquid crystal panel manufacturing process without cutting out a predetermined set of roll-shaped polarizing plates into sheets, so that the sheet-shaped polarizing plates are cut out from the roll-shaped polarizing plates, It is possible to solve problems such as the complexity of packing, transportation, and unpacking, which are involved in the conventional method of using this for the manufacturing process of the liquid crystal panel.

  Furthermore, according to the present invention, since polarizing plates are bonded to both surfaces of a liquid crystal cell with good axial accuracy, it is possible to provide a liquid crystal panel that is less likely to leak light when applied to a liquid crystal display device and has excellent visibility. Can do. The roll-shaped polarizing plate set and the liquid crystal panel of the present invention can be suitably applied to a liquid crystal display device, particularly a liquid crystal display device for a large screen liquid crystal television.

It is the schematic which shows an example of the 1st conveyance process and the 1st polarizing plate supply bonding process in the manufacturing method of the liquid crystal panel of this invention. It is the schematic which shows an example of the 1st conveyance process and the 1st polarizing plate supply bonding process in the manufacturing method of the liquid crystal panel of this invention. It is the schematic which shows an example of the 1st conveyance process and the 1st polarizing plate supply bonding process in the manufacturing method of the liquid crystal panel of this invention. It is the schematic which shows an example of the 1st conveyance process and the 1st polarizing plate supply bonding process in the manufacturing method of the liquid crystal panel of this invention. It is the schematic which shows an example of the manufacturing method of the liquid crystal panel of this invention. It is the schematic which shows an example of the manufacturing method of the liquid crystal panel of this invention. It is a schematic sectional drawing which shows an example of the fundamental layer structure of the liquid crystal panel manufactured by the method of this invention, and the liquid crystal display device to which this is applied.

<Set of roll-shaped polarizing plate>
The set of roll-shaped polarizing plates of the present invention comprises two roll-shaped polarizing plates, a first roll-shaped polarizing plate and a second roll-shaped polarizing plate, which are used as components of a liquid crystal panel. . The liquid crystal panel can be produced by laminating polarizing plates on both sides of the liquid crystal cell. Each of the first roll-shaped polarizing plate and the second roll-shaped polarizing plate is a roll obtained by winding a long polarizing plate to form a back-side polarizing plate and a viewing-side polarizing plate of the liquid crystal panel. Here, “back-side polarizing plate” means a polarizing plate located on the backlight side when the liquid crystal panel is mounted on a liquid crystal display device, and “viewing-side polarizing plate” means that the liquid crystal panel is liquid crystal display It means a polarizing plate located on the viewing side when mounted on the apparatus. Hereinafter, each roll-shaped polarizing plate will be described in detail.

(First roll-shaped polarizing plate)
The first roll-shaped polarizing plate is used as a back-side polarizing plate of a liquid crystal panel, and includes a protective film made of a transparent resin, a first polarizing film made of a polyvinyl alcohol-based resin, and an in-plane retardation value R. ₀ is in the range of 30 to 200 nm, the thickness direction retardation R _th is in the range of 100 to 350 nm, and the biaxial retardation film made of a polyolefin resin, a first adhesive layer, a first It is composed of a long polarizing plate formed by laminating a release film in this order, and the absorption axis of the first polarizing film is parallel to the long side direction of the long polarizing plate. It is wound in a roll shape with a width corresponding to the side. The winding direction of the first roll-shaped polarizing plate is not particularly limited. For example, the first roll-shaped polarizing plate can be wound so that the first release film side is the inside.

  The “width corresponding to the long side of the liquid crystal cell” refers to a width appropriately set according to the length of the long side of the liquid crystal cell to which the first roll-shaped polarizing plate is bonded. The length of the side and the width of the first roll-shaped polarizing plate are not necessarily the same.

(1) First polarizing film As the first polarizing film, a uniaxially stretched polyvinyl alcohol-based resin film having a dichroic dye adsorbed and oriented can be used. As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. As the polyvinyl acetate resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, polyvinyl acetate and Examples thereof include copolymers with other copolymerizable monomers. 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. The polyvinyl alcohol resin may be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

  A film obtained by forming such a polyvinyl alcohol resin is used as a raw film of the first polarizing film. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the thickness of a polyvinyl alcohol-type raw film is not specifically limited, For example, it is about 10-150 micrometers.

  The first polarizing film is usually a step of uniaxially stretching such a polyvinyl alcohol resin film, a step of adsorbing a dichroic dye by dyeing the polyvinyl alcohol resin film with a dichroic dye, two colors It is manufactured through a step of treating a polyvinyl alcohol-based resin film adsorbed with a functional dye with a boric acid aqueous solution and a step of washing with water after the treatment with the boric acid aqueous solution.

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing with the dichroic dye, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, uniaxial stretching can also be performed in a plurality of stages shown here. For uniaxial stretching, a method of stretching uniaxially between rolls having different peripheral speeds, a method of stretching uniaxially using a hot roll, or the like can be adopted. The uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which a polyvinyl alcohol-based resin film is swollen using a solvent such as water. The draw ratio is usually about 3 to 8 times.

  The polyvinyl alcohol resin film can be dyed with the dichroic dye by, for example, a method of immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye. Specifically, iodine or a dichroic dye is used as the dichroic dye. In addition, it is preferable to perform the process which a polyvinyl alcohol-type resin film swells by immersing in 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, and the content of potassium iodide is usually about 0.5 to 20 parts by weight per 100 parts by weight of water. It is. 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 1,800 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, 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 be performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The boric acid content in the boric acid-containing aqueous solution is usually about 2 to 15 parts by weight, preferably about 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 content of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by weight, preferably about 5 to 12 parts by weight per 100 parts by weight of water. The immersion time 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, preferably 50 to 85 ° C., more preferably 60 to 80 ° 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., and the immersion time is usually about 1 to 120 seconds.

  After washing with water, a drying process is performed to obtain a first polarizing film. The drying process can be performed using a hot air dryer or a far infrared heater. The temperature of a drying process is about 30-100 degreeC normally, Preferably it is 50-80 degreeC. The drying time is usually about 60 to 600 seconds, preferably 120 to 600 seconds.

  In this way, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a first polarizing film. The thickness of the first polarizing film can be, for example, about 2 to 40 μm.

(2) Protective film made of transparent resin The protective film made of the transparent resin constituting the first roll-shaped polarizing plate is not particularly limited. Examples of the transparent resin include (meth) acrylic resin such as methyl methacrylate resin ((meth) acrylic resin means methacrylic resin or acrylic resin), olefin resin, polyvinyl chloride Resin, cellulose resin, styrene resin, acrylonitrile / butadiene / styrene copolymer resin, acrylonitrile / styrene copolymer resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, polycarbonate Resin, modified polyphenylene ether resin, polyester resin (for example, polybutylene terephthalate resin, polyethylene terephthalate resin, etc.), polysulfone resin, polyethersulfone resin, polyarylate resin, polyamideimide resin, It can be mentioned imide resin, an epoxy resin, an oxetane-based resin. These resins can contain additives as long as they do not impair transparency and adhesiveness with a polarizing film.

  These transparent resins may be formed into a film and subjected to a stretching treatment to form a protective film. At this time, the stretching is uniaxial stretching that extends in MD (flow direction) or TD (direction perpendicular to the flow direction), biaxial stretching that extends in both MD and TD, and stretching in a direction that is neither MD nor TD. Any method such as oblique stretching may be used.

  The (meth) acrylic resin may be a material containing rubber fine particles as necessary. A (meth) acrylic resin containing rubber particles has high toughness and enables thinning of the film.

  The polyethylene terephthalate-based resin means a resin in which 80 mol% or more of repeating units are composed of ethylene terephthalate, and may include a structural unit derived from another copolymer component. Other copolymer components include isophthalic acid, 4,4′-dicarboxydiphenyl, 4,4′-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthale Acid, dicarboxylic acid components such as 1,4-dicarboxycyclohexane; propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. A diol component is mentioned. These dicarboxylic acid components and diol components can be used in combination of two or more if necessary. It is also possible to use a hydroxycarboxylic acid such as p-hydroxybenzoic acid or p-β-hydroxyethoxybenzoic acid together with the carboxylic acid component or diol component. As other copolymerization component, a dicarboxylic acid component and / or a diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond or the like may be used.

  Using the above polyethylene terephthalate-based resin as a protective film after stretching as described above provides excellent mechanical properties, solvent resistance, scratch resistance, cost, etc., and reduced thickness. A roll-shaped polarizing plate can be obtained.

  With the above cellulose-based resin, some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (broadwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Cellulose organic acid ester or cellulose mixed organic acid ester. Examples include cellulose acetates, propionate esters, butyrate esters, and mixed esters thereof. Among these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, or the like is preferably used.

  Examples of the olefin resins include cyclic polyolefin resins obtained by polymerizing cyclic polyolefin monomers such as norbornene or other cyclopentadiene derivatives using a polymerization catalyst, and chain olefin monomers such as ethylene or propylene. Examples thereof include a chain olefin resin polymerized using a catalyst.

  Here, as the cyclic polyolefin-based resin, for example, a resin obtained by performing ring-opening metathesis polymerization using cyclopentadiene and olefins as a monomer with norbornene or a derivative thereof obtained by Diels-Alder reaction; Resins obtained by ring-opening metathesis polymerization from cyclopentadiene and olefins or methacrylic acid esters using tetracyclododecene or its derivatives obtained by Diels-Alder reaction, followed by hydrogenation; norbornene, tetracyclodone A resin obtained by carrying out ring-opening metathesis copolymerization in the same manner using two or more selected from decene and derivatives thereof and other cyclic polyolefin monomers, followed by hydrogenation; norbornene The tetracyclododecene or a derivative thereof, resins obtained by addition copolymerization of aromatic compounds and the like having a vinyl group.

  Examples of chain olefin resins include polyethylene resins and polypropylene resins.

When a polypropylene resin is selected as the constituent resin of the protective film, there are the following advantages. That is, the polypropylene-based resin has a small photoelastic coefficient of about 2 × 10 ⁻¹³ cm ² / dyne and low moisture permeability. A liquid crystal display device having excellent durability under conditions can be obtained. Furthermore, the adhesiveness of the polypropylene resin film to the polarizing film is good if not as high as that of the triacetyl cellulose film. When various known adhesives are used, the polypropylene resin film has sufficient strength to be polyvinyl alcohol. It can adhere to a polarizing film made of a resin.

  The polypropylene resin may be composed of a propylene homopolymer, or may be a copolymer of propylene as a main component and a small amount of a comonomer copolymerizable therewith. The polypropylene resin made of a copolymer may be a resin containing a comonomer unit in a range of, for example, 20% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less. Further, the content of the comonomer unit in the copolymer is preferably 1% by weight or more, more preferably 3% by weight or more. By setting the content of the comonomer unit to 1% by weight or more, processability and transparency can be significantly improved. On the other hand, when the content of the comonomer unit exceeds 20% by weight, the melting point of the polypropylene resin is lowered and the heat resistance tends to be lowered. In addition, when setting it as the copolymer of 2 or more types of comonomer, and propylene, it is preferable that the total content of the unit derived from all the comonomer contained in the copolymer is the said range.

  The comonomer copolymerized with propylene can be, for example, ethylene or an α-olefin having 4 to 20 carbon atoms. Specific examples of the α-olefin include the following.

1-butene, 2-methyl-1-propene (above C ₄ );
1-pentene, 2-methyl-1-butene, 3-methyl-1-butene (above C ₅ );
1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3- Dimethyl-1-butene (above C ₆ );
1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl-1-butene (above C ₇ );
1-octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl-1-pentene, 2,3,4-trimethyl- 1-pentene, 2-propyl-1-pentene, 2,3-diethyl-1-butene (above C ₈ );
1-nonene (C ₉ ); 1-decene (C ₁₀ ); 1-undecene (C ₁₁ );
1-dodecene (C ₁₂ ); 1-tridecene (C ₁₃ ); 1-tetradecene (C ₁₄ );
1-pentadecene (C ₁₅ ); 1-hexadecene (C ₁₆ ); 1-heptadecene (C ₁₇ );
1-octadecene (C ₁₈ ); 1-nonadecene (C ₁₉ ) and the like.

  Among the α-olefins, α-olefins having 4 to 12 carbon atoms are preferable. Specifically, 1-butene, 2-methyl-1-propene; 1-pentene, 2-methyl-1-butene, 3 -Methyl-1-butene; 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1 -Pentene, 3,3-dimethyl-1-butene; 1-heptene, 2-methyl-1-hexene, 2,3-dimethyl-1-pentene, 2-ethyl-1-pentene, 2-methyl-3-ethyl -1-butene; 1-octene, 5-methyl-1-heptene, 2-ethyl-1-hexene, 3,3-dimethyl-1-hexene, 2-methyl-3-ethyl-1-pentene, 2,3 , 4-Trimethyl-1-pentene 2-propyl-1-pentene, 2,3-diethyl-1-butene; 1-nonene; 1-decene; 1-undecene; 1-dodecene, and the like. From the viewpoint of copolymerizability, 1-butene, 1-pentene, 1-hexene and 1-octene are preferable, and 1-butene and 1-hexene are more preferable.

  The copolymer may be a random copolymer or a block copolymer. Preferred copolymers include propylene / ethylene copolymers and propylene / 1-butene copolymers. In the propylene / ethylene copolymer and propylene / 1-butene copolymer, the ethylene unit content and the 1-butene unit content are, for example, those of “Polymer Analysis Handbook” (1995, published by Kinokuniya Shoten) Infrared (IR) spectrum measurement can be performed by the method described on page 616.

  From the viewpoint of improving the transparency and processability as a protective film made of a transparent resin bonded to the first polarizing film, the copolymer is a random copolymer of propylene mainly composed of propylene and ethylene or the above α-olefin. It is preferably a coalescence, and more preferably a random copolymer of propylene and ethylene. As described above, the content of the ethylene unit in the propylene / ethylene random copolymer is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, and 3 to 7% by weight. Is more preferable.

  The stereoregularity of the polypropylene resin may be any of isotactic, syndiotactic, and atactic. In the present invention, a syndiotactic or isotactic polypropylene resin is preferably used from the viewpoint of heat resistance.

  The polypropylene resin preferably has a melt flow rate (MFR) measured in a temperature of 230 ° C. and a load of 21.18 N within a range of 0.1 to 200 g / 10 minutes in accordance with JIS K 7210. More preferably, it is in the range of 5 to 50 g / 10 min. By using a polypropylene resin having an MFR within this range, a uniform polypropylene resin film can be obtained without imposing a large load on the extruder.

The polypropylene resin can be produced by a method of homopolymerizing propylene using a known polymerization catalyst or a method of copolymerizing propylene and another copolymerizable comonomer. Examples of known polymerization catalysts include the following.
(1) Ti—Mg-based catalyst comprising a solid catalyst component containing magnesium, titanium and halogen as essential components,
(2) a catalyst system in which a solid catalyst component containing magnesium, titanium and halogen as essential components is combined with an organoaluminum compound and, if necessary, a third component such as an electron donating compound,
(3) Metallocene catalysts.

  Among these catalyst systems, the catalyst system of the above (2) can be most generally used in the production of the polypropylene resin used as the constituent resin of the protective film in the present invention. Preferred examples of the organoaluminum compound in the catalyst system of the above (2) include triethylaluminum, triisobutylaluminum, a mixture of triethylaluminum and diethylaluminum chloride, tetraethyldialumoxane, etc. Preferred examples of the electron donating compound Examples thereof include cyclohexylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butylethyldimethoxysilane, and dicyclopentyldimethoxysilane.

  Examples of the solid catalyst components (1) and (2) include catalyst systems described in JP-A-61-218606, JP-A-61-287904, JP-A-7-216017, and the like. It is done. Examples of the metallocene catalyst (3) include catalyst systems described in Japanese Patent No. 2587251, Japanese Patent No. 2627669, Japanese Patent No. 2668732, and the like.

  Polypropylene resins are, for example, solution polymerization methods using an inert solvent typified by hydrocarbon compounds such as hexane, heptane, octane, decane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, and liquid monomers as solvents. It can be produced by a bulk polymerization method to be used or 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.

  A well-known additive may be mix | blended with the polypropylene resin. Examples of the additive include an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant, a nucleating agent, an antifogging agent, and an antiblocking agent. Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, hindered amine light stabilizers, and the like, and for example, phenolic antioxidant mechanisms in one molecule. It is also possible to use a composite antioxidant having a unit having both a phosphorus-based antioxidant mechanism and a phosphorus-based antioxidant mechanism. Examples of the UV absorber include UV absorbers such as 2-hydroxybenzophenone and hydroxyphenylbenzotriazole, and benzoate UV blockers. The antistatic agent may be polymer type, oligomer type or monomer type. Examples of the lubricant include higher fatty acid amides such as erucic acid amide and oleic acid amide, higher fatty acids such as stearic acid, and salts thereof. Examples of the nucleating agent include sorbitol nucleating agents, organophosphate nucleating agents, and polymer nucleating agents such as polyvinylcycloalkane. As the anti-blocking agent, fine particles having a spherical shape or a shape close thereto can be used regardless of inorganic type or organic type. As for said additive, multiple types may be used together.

  Polypropylene resin can be formed into a protective film by any method. This protective film is transparent and has substantially no in-plane retardation. For example, a polypropylene system having substantially no in-plane retardation by extrusion molding from a molten resin, solvent casting method in which a resin dissolved in an organic solvent is cast on a flat plate, and the solvent is removed to form a film. A protective film made of a resin can be obtained.

  A method for producing a protective film made of polypropylene resin by extrusion molding will be described in detail. In extrusion molding, a polypropylene resin is melt-kneaded by rotation of a screw in an extruder and extruded from a T die into a sheet. The temperature of the molten sheet to be extruded is about 180 to 300 ° C. If the temperature of the molten sheet at this time is lower than 180 ° C., the spreadability is not sufficient, the thickness of the resulting film becomes non-uniform, and there is a possibility that the film has phase difference unevenness. Moreover, when the temperature exceeds 300 ° C., the resin is easily deteriorated or decomposed, and bubbles may be generated in the molten sheet or carbides may be contained.

The extruder may be a single screw extruder or a twin screw extruder. For example, when a single screw extruder is used, L / D, which is the ratio of the screw length L to the diameter D, is about 24 to 36, the screw groove space volume V ₁ in the resin supply section, and the screw groove in the resin metering section. The compression ratio V ₁ / V _2, which is the ratio to the space volume V ₂ , is about 1.5 to 4, and a screw of a full flight type, a barrier type or a type having a knead type kneading part is used. it can. Barrier type in which L / D is 28 to 36 and compression ratio V ₁ / V ₂ is 2.5 to 3.5 from the viewpoint of suppressing deterioration and decomposition of polypropylene resin and uniformly melting and kneading It is preferable to use a screw.

  Moreover, in order to suppress deterioration and decomposition | disassembly of polypropylene resin as much as possible, it is preferable to make the inside of an extruder into a nitrogen atmosphere or a vacuum. Furthermore, in order to remove the volatile gas generated when the polypropylene-based resin deteriorates or decomposes, it is also preferable to provide an orifice of about 1 mmφ to 5 mmφ at the tip of the extruder to increase the resin pressure at the tip of the extruder. Increasing the resin pressure at the leading end of the extruder by installing an orifice means increasing the back pressure at the leading end, thereby improving the stability of extrusion. The diameter of the orifice to be used is more preferably 2 mmφ or more and 4 mmφ or less.

  The T-die used for extrusion preferably has no fine steps or scratches on the resin flow path surface, and the lip portion is plated or coated with a material having a low coefficient of friction with the molten polypropylene resin. Further, a sharp edge shape with a lip tip polished to 0.3 mmφ or less is preferable. Examples of the material having a small friction coefficient include tungsten carbide type and fluorine type special plating. By using such a T-die, it is possible to suppress the generation of eyes and simultaneously suppress the die line, so that a resin film having excellent appearance uniformity can be obtained. In the T-die, the manifold has a coat hanger shape and preferably satisfies the following condition (i) or (ii), and more preferably satisfies the condition (iii) or (iv).

(I) When the lip width of the T die is less than 1500 mm: the thickness direction length of the T die> 180 mm,
(Ii) When the lip width of the T die is 1500 mm or more: the thickness direction length of the T die> 220 mm,
(Iii) When the lip width of the T die is less than 1500 mm: the length in the height direction of the T die> 250 mm,
(Iv) When the lip width of the T die is 1500 mm or more: Length in the height direction of the T die> 280 mm.

  By using a T die that satisfies these conditions, the flow of the molten polypropylene resin inside the T die can be adjusted, and the lip portion can be extruded while suppressing thickness unevenness, so that the thickness is increased. A protective film made of a polypropylene resin having excellent accuracy and a more uniform retardation can be obtained.

  In addition, it is preferable to attach a gear pump via an adapter between an extruder and a T die from a viewpoint of suppressing the extrusion fluctuation | variation of polypropylene resin. In addition, it is preferable to attach a leaf disk filter to remove foreign substances in the polypropylene resin.

  The protective film made of polypropylene resin is an elastic body that rotates by pressing a molten sheet extruded from a T-die into a metal cooling roll (also called a chill roll or a casting roll) in the circumferential direction of the metal cooling roll. It can obtain by pinching between touch rolls containing and solidifying by cooling. In this case, the touch roll may be one in which an elastic body such as rubber is directly on the surface, or may be one in which the surface of the elastic body roll is covered with an outer cylinder made of a metal sleeve. When using a touch roll in which the surface of the elastic roll is covered with an outer cylinder made of a metal sleeve, cooling is usually performed by directly sandwiching a molten sheet of polypropylene resin between the metal cooling roll and the touch roll. . On the other hand, in the case of using a touch roll whose surface is an elastic body, a biaxially stretched film of a thermoplastic resin can be interposed between the molten sheet of polypropylene resin and the touch roll for sandwiching.

  When the molten sheet of polypropylene resin is cooled and solidified by being sandwiched between the cooling roll and the touch roll as described above, the surface temperature of the cooling roll and the touch roll may be lowered to rapidly cool the molten sheet. preferable. For example, the surface temperature of both rolls is preferably adjusted to a range of 0 ° C. or higher and 30 ° C. or lower. When these surface temperatures exceed 30 ° C., it takes time to cool and solidify the molten sheet, so that the crystal component in the polypropylene resin grows, and the resulting film may be inferior in transparency. . On the other hand, when the surface temperature of the roll is lower than 0 ° C., the surface of the metal cooling roll is dewed and water droplets are attached, and the appearance of the resulting film tends to be deteriorated.

  Since the metal cooling roll to be used is transferred to the surface of the protective film made of polypropylene resin, the surface state of the metal cooling roll may reduce the thickness accuracy of the protective film to be obtained if the surface is uneven. is there. Therefore, it is preferable that the surface of the metal cooling roll is in a mirror surface state as much as possible. Specifically, the roughness of the surface of the metal cooling roll is preferably 0.4 S or less, more preferably 0.05 S to 0.2 S, expressed as a standard sequence of the maximum height. .

  The touch roll that forms the nip portion with the metal cooling roll has a surface hardness of 65 to 80 as a value measured by a spring type hardness test (A type) defined in JIS K 6301. It is preferable that it is 70-80. By using such a surface hardness touch roll, it becomes easy to maintain a uniform linear pressure applied to the molten sheet, and a bank (resin) of the molten sheet is provided between the metal cooling roll and the touch roll. It becomes easy to form into a film without causing a stagnation.

  The pressure (linear pressure) when sandwiching the molten sheet is determined by the pressure for pressing the touch roll against the metal cooling roll. The linear pressure is preferably 50 N / cm or more and 300 N / cm or less, and more preferably 100 N / cm or more and 250 N / cm or less. By setting the linear pressure within the above range, it becomes easy to produce a protective film made of a polypropylene resin while maintaining a constant linear pressure without forming a bank.

  When sandwiching a biaxially stretched film of a thermoplastic resin together with a molten sheet of polypropylene resin between a metal cooling roll and a touch roll, the thermoplastic resin constituting the biaxially stretched film is a polypropylene resin and Any resin that does not strongly heat-seal can be used. Specific examples include polyester, polyamide, polyvinyl chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and polyacrylonitrile. Among these, polyesters that have little dimensional change due to humidity, heat, and the like are most preferable. The thickness of the biaxially stretched film is usually about 5 to 50 μm, preferably 10 to 30 μm.

  The distance (air gap) from the lip of the T die to the pressure between the metal cooling roll and the touch roll is preferably 200 mm or less, and more preferably 160 mm or less. The molten sheet extruded from the T-die is stretched from the lip to the roll, and orientation tends to occur. By shortening the air gap as described above, a film having a smaller orientation can be obtained. The lower limit value of the air gap is determined by the diameter of the metal cooling roll to be used, the diameter of the touch roll, and the tip shape of the lip to be used, and is usually 50 mm or more.

  The processing speed when producing a protective film made of a polypropylene resin is determined by the time required for cooling and solidifying the molten sheet. When the diameter of the metal cooling roll to be used is increased, the distance at which the molten sheet is in contact with the cooling roll becomes longer, so that production at a higher speed is possible. Specifically, when a 600 mmφ metal cooling roll is used, the processing speed is about 5 to 20 m / min at the maximum.

  The molten sheet sandwiched between the metal cooling roll and the touch roll is cooled and solidified by contact with the roll. And after slitting an edge part as needed, it is wound up by a winder and turns into a roll-shaped protective film. In addition, in order to protect the surface until it uses a protective film in the case of winding, you may wind up in the state which bonded the surface protective film which consists of another thermoplastic resin to the single side | surface or both surfaces. . When a molten sheet of polypropylene resin is sandwiched between a metal cooling roll and a touch roll together with a biaxially stretched film made of a thermoplastic resin, the biaxially stretched film is used as one surface protective film. You can also.

  The thickness of the protective film made of a transparent resin is usually 20 to 200 μm, preferably 20 to 120 μm. When the thickness of the protective film is less than 20 μm, the handling property tends to be inferior, and even when the thickness exceeds 200 μm, the handling property may be lowered due to the increased rigidity of the film.

A protective film made of a transparent resin needs to be excellent in transparency. Specifically, the haze value measured according to JIS K 7105 is 10% or less, preferably 7% or less. When the haze value exceeds 10%, when the obtained polarizing plate is applied to a liquid crystal display device, white luminance tends to decrease and the screen tends to become dark. The haze value measured according to JIS K 7105 is the following formula:
(Diffuse transmittance / total light transmittance) × 100 (%)
Defined by

  On the surface opposite to the first polarizing film of the protective film made of transparent resin, from the viewpoint of preventing scratches in the manufacturing process of the liquid crystal panel or the liquid crystal display device using the same, hard coat treatment, prism sheet and color filter Anti-glare processing may be performed from the viewpoint of reducing moire due to interference.

  Moreover, you may laminate | stack a protective film or an adhesive layer on the surface on the opposite side to the 1st polarizing film of the protective film which consists of transparent resin. Furthermore, an optical film such as a reflective polarizing film as exemplified in the “DBEF series” sold by 3M Company may be provided through the adhesive layer.

(3) Biaxial retardation film The biaxial retardation film is made of a polyolefin-based resin, has an in-plane retardation value R ₀ in the range of 30 to 200 nm, and has a thickness direction retardation value R _th of 100 to 100. It is in the range of 350 nm. The in-plane retardation value R ₀ and the thickness direction retardation value R _th here are values at a wavelength of 590 nm, and so on.

  The biaxial retardation film preferably has a Gurley bending resistance measured in accordance with JIS L 1096 of 350 mgf or less, more preferably 200 mgf or less, and even more preferably 150 mgf or less. preferable. In this way, by using a biaxial retardation film having a low bending resistance, the rigidity of the obtained first roll-shaped polarizing plate is reduced, so that the handling property when bonding to a liquid crystal cell is improved. Can be made. Moreover, when the biaxial retardation film is made of a polyolefin resin, light leakage in the display area of the obtained liquid crystal display device can be improved because the photoelastic coefficient of the polyolefin resin is small. Here, light leakage means that when the liquid crystal panel receives a thermal history, the retardation value of the protective film or retardation film on the liquid crystal cell side or the axial angle with the polarizing film changes due to the shrinkage of the polarizing film. When the liquid crystal display device displays black, light is emitted from the four side ends or four corners of the display area, and the portion becomes whitish. When the protective film or retardation film located on the liquid crystal cell side has a large photoelastic coefficient, such light leakage tends to appear.

  The biaxial retardation film is preferably made of a polypropylene resin or a cyclic polyolefin resin. As described above, by using a polypropylene resin or a cyclic polyolefin resin having a low elastic modulus, a film having a low Gurley stiffness is easily obtained. Moreover, since the polypropylene resin film and the cyclic polyolefin resin film have small moisture permeability, the durability of the obtained polarizing plate in a high-humidity environment can be improved.

  As the polyolefin resin constituting the biaxial retardation film, the polyolefin resins listed above as resins that can constitute a protective film made of a transparent resin may be used alone or in combination of two or more. May be. These polyolefin resins can also be used after any suitable polymer modification. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, stereoregularity control, and reaction between different polymers. Modification including mixing including the case involving, for example, ethylene-propylene copolymer resin and the like.

  A polypropylene-based resin film suitable as a biaxial retardation film is obtained by stretching an unstretched film made of a polypropylene-based resin previously listed as a resin that can constitute a protective film made of a transparent resin to develop a retardation. This is an axial retardation film. In particular, those in which biaxial birefringence is expressed by successive biaxial stretching are preferred. The stretching ratio at this time is approximately 1.1 to 10 times in the direction in which the optical axis is expressed (the direction in which the stretching ratio is large and the slow axis) in the longitudinal direction and the transverse direction, and is orthogonal thereto. What is necessary is just to select suitably from the range of about 1.1-7 times by the direction (direction where a draw ratio is small, and becomes a fast axis) according to the required phase difference value. The optical axis may be developed in the lateral direction of the film, or the optical axis may be developed in the longitudinal direction.

The retardation value of the biaxial retardation film will be described. The refractive index of in-plane slow axis direction n _x of the film, the refractive index n _y in-plane fast axis direction (direction orthogonal with the slow axis and the plane), the refractive index in the thickness direction n _z, thickness Where d is the in-plane retardation value R ₀ and the thickness direction retardation value R _th are defined by the following expressions (I) and (II), respectively.

_{R 0 = (n x -n y} ) × d (I)
_Rth = [( _nx + _ny ) / 2- _nz ] * d (II).

Furthermore, the biaxial retardation film has the following formula (III) with respect to its refractive index:
_nx > _ny > _nz (III)
It satisfies the relationship.

In the present invention, a biaxial retardation film having an in-plane retardation value R ₀ in the range of 30 to 200 nm and a thickness direction retardation value R _th in the range of 100 to 350 nm is used. From the range, the phase difference value may be appropriately selected in accordance with the characteristics required for the liquid crystal display device to be applied. The in-plane retardation value R ₀ is preferably 120 nm or less, and the thickness direction retardation value R _th is preferably 150 nm or more and 300 nm or less.

The accuracy of the in-plane retardation value R ₀ is within the center value ± 7 nm, preferably within the center value ± 5 nm, and the accuracy of the thickness direction retardation value R _th is within the center value ± 15 nm, preferably the center value ± 10 nm. Is within. If the accuracy of these values exceeds the above range, the visual characteristics of the applied liquid crystal display device tend to deteriorate.

  The slow axis angle in the film plane of the biaxial retardation film is substantially 0 ° or 90 °. If the slow axis deviates from this angle, light leakage occurs when the polarizing plate is placed in a crossed Nicol state, and when applied to a liquid crystal display device, visual characteristics such as front contrast tend to be greatly reduced. . The accuracy of the slow axis is preferably within the center value ± 0.7 °, and more preferably within the center value ± 0.5 °. Here, light leakage refers to a phenomenon in which light leaks from the entire display area when the liquid crystal display device displays black when the axial accuracy of the polarizing film with respect to the retardation film or the axial accuracy of the polarizing plate with respect to the liquid crystal cell is poor. As described above, by reducing the shift of the slow axis in the biaxial retardation film, and thus by reducing the shift of the angle between the slow axis and the absorption axis of the polarizing film, as described later, To improve the axial accuracy of the polarizing plates (the first polarizing plate and the second polarizing plate) bonded to the front and back surfaces of the liquid crystal cell and to reduce the deviation from 90 ° of the angle formed by the absorption axes of both polarizing plates. Thus, light leakage can be reduced.

Polypropylene resin phase difference is easily expressed by stretching, therefore, the difference between n _x and n _y in the formula (I) ~ (III) or a difference between n _x and n _y and n _z, is likely to increase. Therefore, a film obtained by stretching such a polypropylene resin film can exhibit a desired retardation value by appropriate stretching even if the thickness d is reduced. Therefore, the thickness of the biaxial retardation film used in the present invention may be 60 μm or less. However, if it is too thin, the handleability may be lowered, and therefore it is preferably 5 μm or more. The thickness of the biaxial retardation film is more preferably 10 μm or more and 40 μm or less.

  In adhering the biaxial retardation film to the first polarizing film, the optimal axial relationship between them may be selected in consideration of the viewing angle characteristics and color change characteristics of the target liquid crystal display device. In large liquid crystal television applications where the front contrast is important, the slow axis of the biaxial retardation film and the absorption axis of the polarizing film are often arranged so as to have a substantially parallel or substantially orthogonal relationship. Here, “substantially parallel or substantially orthogonal” includes not only completely parallel or orthogonal, but also a case of deviating from a parallel or orthogonal relationship within a range of about ± 10 °. The angle deviation is preferably within ± 5 °, more preferably within ± 2 °. The slow axis of the biaxial retardation film and the absorption axis of the polarizing film are preferably in a completely parallel or orthogonal relationship.

(4) Adhesive layer Bonding and lamination of a protective film made of a transparent resin and a biaxial retardation film on the first polarizing film are usually performed via an adhesive layer. The adhesive that forms the adhesive layer provided on both surfaces of the first polarizing film may be the same or different.

  From the viewpoint of rapid curability and the productivity improvement of the roll-shaped polarizing plate associated therewith, a photocurable adhesive can be mentioned as an example of a preferable adhesive for forming the adhesive layer. As a photocurable adhesive agent, the curable composition etc. which contain a photocurable epoxy resin and a photocationic polymerization initiator can be mentioned, for example.

  Further, from the viewpoint of thinning the adhesive layer, an aqueous adhesive, that is, an adhesive in which an adhesive component is dissolved in water or an adhesive component is dispersed in water can be used as the adhesive. For example, an aqueous composition using a polyvinyl alcohol resin or a urethane resin as a main component can be mentioned as a preferred aqueous adhesive.

  Polyvinyl alcohol resins as the main component of the adhesive include partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified polyvinyl alcohol. It may be a modified polyvinyl alcohol resin such as alcohol. An aqueous adhesive whose main component is an polyvinyl alcohol resin is often prepared as an aqueous solution of a polyvinyl alcohol resin. The density | concentration of the polyvinyl alcohol-type resin in a water-system adhesive agent is about 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  In order to improve the adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to an aqueous adhesive containing a polyvinyl alcohol resin as a main component. Examples of water-soluble epoxy resins include polyamides obtained by reacting epichlorohydrin with polyamide polyamines obtained by reacting polyalkylene polyamines such as diethylenetriamine and triethylenetetramine with dicarboxylic acids such as adipic acid. Mention may be made of polyamine epoxy resins. Commercially available products of such polyamide polyamine epoxy resins include “Smiles Resin 650” and “Smiles Resin 675” sold by Sumika Chemtex Co., Ltd., and “WS-525” sold by Japan PMC Co., Ltd. Etc., and these can be preferably used. The addition amount of these curable components or crosslinking agents is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight, with respect to 100 parts by weight of the polyvinyl alcohol resin. If the amount added is small, the effect of improving the adhesiveness is reduced, while if the amount added is large, the adhesive layer tends to be brittle.

  When a urethane resin is used as the main component of the adhesive, examples of suitable water-based adhesives include a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly into water without using an emulsifier and becomes an emulsion. Polyester ionomer urethane resins are known per se. For example, Japanese Patent Application Laid-Open No. 7-97504 describes a polyester ionomer type urethane resin as an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium, and Japanese Patent Application Laid-Open No. 2005-070140. In JP-A-2005-181817, a cycloolefin resin film is bonded to a polarizing film made of a polyvinyl alcohol resin using a mixture of a polyester ionomer urethane resin and a compound having a glycidyloxy group as an adhesive. The form is shown.

  As a method of bonding the protective film and the biaxial retardation film made of a transparent resin to the first polarizing film surface using an adhesive, a conventionally known method can be used, for example, a casting method. Adhered to the adhesive surface of the first polarizing film and / or the film to be bonded by the Meyer bar coating method, gravure coating method, comma coater method, doctor plate method, die coating method, dip coating method, spraying method, etc. The method of apply | coating an agent and superimposing both is mentioned. The casting method is a method of spreading and spreading an adhesive on the surface of a film to be coated while moving it in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between the two.

  After apply | coating an adhesive agent by the said method, both are joined by pinching | interposing a 1st polarizing film and the film bonded by it with a nip roll. Moreover, after dripping an adhesive agent between the 1st polarizing film and the film bonded to it, the method of pressurizing this laminated body with a roll etc. and spreading it uniformly can also be used suitably. In this case, a metal, rubber, or the like can be used as the material of the roll. Furthermore, after dripping an adhesive agent between the 1st polarizing film and the film bonded to it, the method of passing this laminated body between rolls and pressurizing and spreading is also employ | adopted preferably. In this case, these rolls may be made of the same material or different materials.

  Note that the thickness of the adhesive layer after being bonded using a nip roll or the like before drying or curing is preferably 5 μm or less, and more preferably 0.01 μm or more.

  In order to improve the adhesiveness, the surface of the first polarizing film and / or the film bonded thereto is a surface such as a plasma treatment, a corona treatment, an ultraviolet irradiation treatment, a flame (flame) treatment, or a saponification treatment. You may perform a process suitably. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

  The laminated body joined through the water-based adhesive is usually subjected to a drying treatment, and the adhesive layer is dried and cured. The drying process can be performed, for example, by blowing hot air. A drying temperature is normally selected from the range of about 40-100 degreeC, Preferably it is 60-100 degreeC. The drying time is, for example, about 20 to 1,200 seconds. The thickness of the adhesive layer after drying is usually about 0.001 to 5 μm, preferably 0.01 μm or more, preferably 2 μm or less, more preferably 1 μm or less. If the thickness of the adhesive layer becomes too large, the appearance of the polarizing plate tends to be poor.

  After the drying treatment, sufficient adhesive strength may be obtained by performing curing at a temperature of room temperature or higher for at least half a day, usually 1 day or longer. Such curing is typically performed in a state of being wound into a roll. The preferable curing temperature is in the range of 30 to 50 ° C, more preferably 35 ° C or more and 45 ° C or less. When the curing temperature exceeds 50 ° C., so-called “roll tightening” is likely to occur in the roll winding state. The humidity during curing is not particularly limited, but is preferably selected so that the relative humidity is in the range of about 0% RH to 70% RH. The curing time is preferably about 1 to 10 days, more preferably about 2 to 7 days.

On the other hand, when joining a 1st polarizing film and the film bonded to it using a photocurable adhesive agent, after joining these films, a photocurable adhesive agent is irradiated by irradiating an active energy ray. Is cured. The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. A microwave excited mercury lamp, a metal halide lamp, or the like is preferably used. The light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 6000 mW. / Cm ² is preferable. When the irradiation intensity is 0.1 mW / cm ² or more, the reaction time does not become too long, and when it is 6000 mW / cm ² or less, it is caused by heat radiated from the light source and heat generated during curing of the photocurable adhesive. There is little risk of yellowing of the photocurable epoxy resin and deterioration of the polarizing film. The light irradiation time to the photocurable adhesive is controlled for each photocurable adhesive to be cured and is not particularly limited, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is It is preferably set to be 10 to 10,000 mJ / cm ² . When the cumulative amount of light to the photocurable adhesive is 10 mJ / cm ² or more, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and at 10,000 mJ / cm ² or less. In some cases, irradiation time does not become too long and good productivity can be maintained. In addition, the thickness of the adhesive bond layer after active energy ray irradiation is about 0.001-5 micrometers normally, Preferably it is 0.01 micrometer or more, More preferably, it is 0.1 micrometer or more.

  When curing a photocurable adhesive by irradiation with active energy rays, various functions of the polarizing plate such as the degree of polarization, transmittance and hue of the first polarizing film, and transparency of the biaxial retardation film and protective film It is preferable to perform the curing under the condition that does not decrease.

(5) 1st adhesive layer The 1st adhesive layer which comprises a 1st roll-shaped polarizing plate bonds a 1st roll-shaped polarizing plate or the polarizing plate cut | judged by this to the liquid crystal cell to a liquid crystal cell. It is used to do. Examples of the pressure-sensitive adhesive forming the first pressure-sensitive adhesive layer include those having an acrylic polymer, silicone-based polymer, polyester, polyurethane, polyether or the like as a base polymer. Among them, acrylic pressure-sensitive adhesives based on acrylic polymers are excellent in optical transparency, maintain appropriate wettability and cohesive strength, and have excellent weather resistance and heat resistance. It is preferably used because it does not easily cause separation problems such as floating and peeling even under conditions.

  The acrylic base polymer constituting the acrylic pressure-sensitive adhesive includes an acrylic acid alkyl ester having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, a butyl group, or a 2-ethylhexyl group, An acrylic copolymer with a functional group-containing (meth) acrylic monomer such as (meth) acrylic acid or 2-hydroxyethyl (meth) acrylate is preferably used. The pressure-sensitive adhesive layer containing such an acrylic copolymer can be compared without causing any adhesive residue on the glass substrate when it has to be peeled off after being bonded to a liquid crystal cell. Can be easily peeled off. The acrylic copolymer used for the pressure-sensitive adhesive preferably has a glass transition temperature of 25 ° C. or lower, more preferably 0 ° C. or lower. The acrylic copolymer usually has a weight average molecular weight of 100,000 or more.

  As a pressure-sensitive adhesive forming the first pressure-sensitive adhesive layer, a diffusion pressure-sensitive adhesive in which a light diffusing agent is dispersed can be used. The light diffusing agent is for imparting light diffusibility to the pressure-sensitive adhesive layer. The light diffusing agent may be fine particles having a refractive index different from that of the base polymer constituting the pressure-sensitive adhesive layer, and fine particles made of an inorganic compound or fine particles made of an organic compound (polymer) can be used. Since the base polymer constituting the pressure-sensitive adhesive layer, including the acrylic base polymer as described above, often has a refractive index of about 1.4, the light diffusing agent has a refractive index of about 1-2. May be selected as appropriate. The difference in refractive index between the base polymer constituting the pressure-sensitive adhesive layer and the light diffusing agent is usually 0.01 or more, and from the viewpoint of ensuring the brightness and visibility of the applied liquid crystal display device, 0.01 to 0. .5 or less is preferable. The fine particles used as the light diffusing agent are preferably spherical and those close to monodisperse, and fine particles having an average particle diameter of about 2 to 6 μm are preferably used.

  Examples of the fine particles made of an inorganic compound include aluminum oxide (refractive index 1.76) and silicon oxide (refractive index 1.45). Examples of the fine particles composed of an organic compound (polymer) include melamine resin beads (refractive index 1.57), polymethyl methacrylate beads (refractive index 1.49), methyl methacrylate / styrene copolymer resin beads ( (Refractive index 1.50 to 1.59), polycarbonate beads (refractive index 1.55), polyethylene beads (refractive index 1.53), polystyrene beads (refractive index 1.6), polyvinyl chloride beads (refractive index 1. 46), silicone resin beads (refractive index 1.46), and the like.

  The amount of the light diffusing agent is appropriately determined in consideration of the haze value required for the pressure-sensitive adhesive layer in which it is dispersed and the brightness of the liquid crystal display device to which it is applied. The amount is about 3 to 30 parts by weight with respect to 100 parts by weight of the base polymer constituting the layer.

  The haze value measured in accordance with JIS K 7105 of the pressure-sensitive adhesive layer in which the light diffusing agent is dispersed is 20% from the viewpoint of ensuring the brightness of the applied liquid crystal display device and making the display image less likely to bleed or blur. It is preferable to make it into the range of -80%.

  Each component (base polymer, light diffusing agent, crosslinking agent, etc.) constituting the transparent pressure-sensitive adhesive or diffusion pressure-sensitive adhesive is dissolved in a suitable solvent such as ethyl acetate to form a pressure-sensitive adhesive composition. However, components that are not soluble in a solvent such as a light diffusing agent are dispersed. A first pressure-sensitive adhesive layer can be formed by applying this pressure-sensitive adhesive composition onto a biaxial retardation film or a first release film and drying it.

  The first pressure-sensitive adhesive layer preferably has antistatic properties in order to eliminate static electricity charged on the polarizing plate. The first roll-shaped polarizing plate may be charged with static electricity when the first release film laminated on the first pressure-sensitive adhesive layer is peeled off and bonded to the liquid crystal cell. If the pressure-sensitive adhesive layer has antistatic properties, the static electricity is quickly eliminated, and the display circuit of the liquid crystal cell is prevented from being broken and the liquid crystal molecules from being disturbed in alignment.

  Examples of a method for imparting antistatic properties to the first pressure-sensitive adhesive layer include a method in which the pressure-sensitive adhesive composition contains metal fine particles, metal oxide fine particles, or fine particles coated with metal, etc .; electrolyte salt and organo Examples thereof include a method of containing an ion conductive composition comprising polysiloxane; a method of blending an organic salt antistatic agent, and the like. The required antistatic holding time is at least about 6 months from the viewpoint of production, distribution and storage period of a general roll-shaped polarizing plate.

  The first pressure-sensitive adhesive layer may pass active energy rays in order to cure the above-described adhesive layer. Therefore, it is preferable to have a high transmittance in the corresponding spectral region of the active energy ray. In addition, it is preferable that various characteristics as an adhesive do not change by irradiation of an active energy ray.

  For example, the first pressure-sensitive adhesive layer is aged for about 3 to 20 days in an environment of a temperature of 23 ° C. and a relative humidity of 65%, and after the reaction of the crosslinking agent has sufficiently progressed, it is used for bonding to a liquid crystal cell. Is done.

  Although the thickness of a 1st adhesive layer is suitably determined according to the adhesive force etc., it is about 1-40 micrometers normally. In order to obtain a thin roll polarizing plate without impairing properties such as workability and durability, the thickness of the pressure-sensitive adhesive layer is preferably about 3 to 25 μm. In addition, when the pressure-sensitive adhesive layer in which the light diffusing agent is dispersed is used, by setting the thickness of the first pressure-sensitive adhesive layer within this range, the brightness when the liquid crystal display device is viewed from the front or obliquely. The display image can be kept from blurring and blurring.

(6) 1st mold release film As a 1st mold release film, what formed the easily peelable layer in the transparent base film normally, and provided the peelability from an adhesive layer is used. Examples of the transparent base film include extruded films of thermoplastic resins such as polyethylene terephthalate, polyethylene naphtholate, polyethylene, and polypropylene, co-extruded films combining them, and films obtained by stretching them uniaxially or biaxially. Can be mentioned.

  The Gurley bending resistance measured according to JIS L 1096 of the first release film is preferably 20 mgf or more, and more preferably 70 mgf or more. When the Gurley method bending resistance is less than 20 mgf, the rigidity of the release film is insufficient, and the handling property may be lowered.

(Second roll-shaped polarizing plate)
The second roll-shaped polarizing plate is used as a viewing side (front side) polarizing plate of a liquid crystal panel, and an antiglare film having a haze value in the range of 0.1 to 45%, and a polyvinyl alcohol resin. The second polarizing film is composed of a long polarizing plate formed by laminating a second polarizing film, a second pressure-sensitive adhesive layer, and a second release film in this order, and the absorption axis of the second polarizing film is It is in a direction parallel to the long side direction of the long polarizing plate and wound in a roll shape with a width corresponding to the short side of the liquid crystal cell. The winding direction of the second roll-shaped polarizing plate is not particularly limited. For example, the second roll-shaped polarizing plate can be wound so that the second release film side is on the inner side.

  The “width corresponding to the short side of the liquid crystal cell” refers to a width appropriately set according to the length of the short side of the liquid crystal cell on which the second roll-shaped polarizing plate is bonded. The length of the side and the width of the second roll-shaped polarizing plate are not necessarily the same.

  As the second polarizing film, a film obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol-based resin film can be used in the same manner as the first polarizing film. The first polarizing film and the second polarizing film may be the same or different with respect to the outer shape (thickness, etc.), material, and manufacturing method.

  As the second pressure-sensitive adhesive layer and the second release film laminated thereon, those described for the first pressure-sensitive adhesive layer and the first release film can be similarly used. The first and second pressure-sensitive adhesive layers and the first and second release films may be the same or different with respect to the outer shape (thickness and the like), the material, the manufacturing method, and the like.

(1) Anti-glare film As an anti-glare film, what is equipped with the transparent resin film used as a base material and the hard-coat layer which has the fine surface uneven | corrugated shape laminated | stacked on the said film surface can be used. . As a transparent resin film, what was demonstrated about the protective film which consists of the said transparent resin can be used similarly.

  The haze value measured according to JIS K 7105 of the antiglare film is 0.1 to 45%, preferably 5 to 40%. When the haze value exceeds 45%, when applied to a liquid crystal display device, reflection of external light can be reduced, but the black display screen is reduced. On the other hand, if the haze value is less than 0.1%, sufficient antiglare performance cannot be obtained, and external light is reflected on the screen, which is not practical.

  The hard coat layer with fine surface irregularities is formed by a method of forming a coating film containing organic fine particles or inorganic fine particles on the transparent resin film surface, or after forming a coating film containing or not containing organic fine particles or inorganic fine particles. Although it can manufacture by the method (for example, embossing method etc.) etc. which press this coating film on the uneven surface of the roll which provided uneven | corrugated shape, it is not limited to these. Examples of the method for forming the coating film include a method in which a coating liquid containing a binder component made of a curable resin and organic fine particles or inorganic fine particles is applied to the surface of the transparent resin film.

  Typical examples of inorganic fine particles include silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate, calcium phosphate, and the like. As the organic fine particles, resin particles such as crosslinked polyacrylic acid particles, methyl methacrylate / styrene copolymer resin particles, crosslinked polystyrene particles, crosslinked polymethyl methacrylate particles, silicone resin particles, and polyimide particles can be used.

  The binder component is preferably selected from materials that have high hardness (hard coat). As the binder component, a photocurable resin, a thermosetting resin, an electron beam curable resin, and the like can be used, and a photocurable resin is preferably used from the viewpoint of productivity, hardness, and the like. A commercially available resin can be used as the photocurable resin. For example, one or more polyfunctional acrylates such as trimethylolpropane triacrylate and pentaerythritol tetraacrylate, “Irgacure 907”, “Irgacure 184” (above, manufactured by Ciba), “Lucirin TPO” (BASF) A mixture with a photopolymerization initiator such as a photocurable resin can be used as a photocurable resin. For example, in the case of using a photocurable resin, after dispersing inorganic fine particles or organic fine particles in the photocurable resin, the resin composition is applied onto a transparent resin film and irradiated with light, thereby photocuring. It is possible to form a hard coat layer in which inorganic fine particles or organic fine particles are dispersed in a hard coat resin made of a cured resin.

  More specific examples of the photocurable resin include a mixture of urethane acrylate, polyol (meth) acrylate, a (meth) acrylic polymer having an alkyl group containing two or more hydroxyl groups, and a photopolymerization initiator. .

  The urethane acrylate is preferably prepared using (meth) acrylic acid and / or (meth) acrylic acid ester, polyol, and diisocyanate. For example, urethane acrylate can be obtained by preparing hydroxy (meth) acrylate having at least one hydroxyl group from (meth) acrylic acid and / or (meth) acrylic acid ester and polyol, and reacting it with diisocyanate. . These (meth) acrylic acid and / or (meth) acrylic acid ester, polyol, and diisocyanate may be used alone or in combination of two or more. Moreover, you may add various additives according to the objective.

  Examples of (meth) acrylic acid esters include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and butyl (meth) acrylate; cyclohexyl ( And cycloalkyl (meth) acrylates such as (meth) acrylate.

  The polyol is a compound having at least two hydroxyl groups, such as ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1 , 4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decane glycol, 2,2,4-trimethyl-1,3-pentanediol, 3-methyl-1,5- Pentanediol, hydroxypivalic acid neopentyl glycol ester, cyclohexanedimethylol, 1,4-cyclohexanediol, spiroglycol, tricyclodecanemethylol, hydrogenated bisphenol A, ethylene oxide-added bisphenol A, propylene oxide De addition bisphenol A, trimethylolethane, trimethylolpropane dimethylol propane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, can be exemplified dipentaerythritol, tripentaerythritol, glucose ethers.

  As the diisocyanate, for example, various aromatic, aliphatic or alicyclic diisocyanates can be used. Specific examples include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3-dimethyl-4,4-diphenyl diisocyanate. , Xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-diphenylmethane diisocyanate, and hydrogenated products thereof.

  Specific examples of the polyol (meth) acrylate include pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,6-hexanediol (Meth) acrylate is mentioned. These may be used alone or in combination. Furthermore, you may add various additives as needed. The polyol (meth) acrylate preferably comprises pentaerythritol triacrylate and pentaerythritol tetraacrylate. These may be a copolymer or a mixture.

  Examples of the (meth) acrylic polymer having an alkyl group containing two or more hydroxyl groups include a (meth) acrylic polymer having a 2,3-dihydroxypropyl group, a 2-hydroxyethyl group, and a 2,3-dihydroxypropyl group. The (meth) acrylic polymer which has is mentioned.

  As the photopolymerization initiator, 2,2-dimethoxy-2-phenylacetophenone, acetophenone, benzophenone, xanthone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoinpropyl ether, benzyldimethyl ketal, List N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, and other thioxanthates. Can do.

  A solvent is added to the mixture containing the photocurable resin as necessary. Although it does not restrict | limit especially as a solvent, For example, ethyl acetate, butyl acetate, and these mixed solvents can be mentioned.

  Moreover, the mixture containing the said photocurable resin may contain a leveling agent, for example, can mention a fluorine type or a silicone type leveling agent. Examples of the silicone leveling agent include reactive silicone, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. Preferred are reactive silicone and siloxane leveling agents. By using reactive silicone, the surface of the hard coat layer is provided with slipperiness, and excellent scratch resistance can be maintained for a long period of time. In addition, when a siloxane leveling agent is used, film formability can be improved.

  As described above, by using an acrylic binder component (photo-curable resin) as exemplified above, adhesion with the transparent resin film is improved, mechanical strength is further improved, and scratches on the surface are more effective. It is possible to obtain an antiglare film that can be prevented.

  In the case of forming a hard coat layer having a fine concavo-convex shape by an embossing method, a curable resin layer in which the concavo-convex shape of the mold is formed on a transparent resin film using a mold having a fine concavo-convex shape. Can be transferred to. The transfer to the mold-shaped curable resin layer is preferably performed by embossing, and as the embossing, a UV embossing method using an ultraviolet curable resin which is a kind of a photocurable resin is preferable. In addition, when forming fine surface uneven | corrugated shape by the embossing method, the hard-coat layer may contain the inorganic or organic fine particle, and does not need to contain it.

  In the UV embossing method, a UV curable resin layer is formed on the surface of a transparent resin film, and the UV curable resin layer is cured by pressing the UV curable resin layer against the rugged surface of the mold. Transferred to the layer. Specifically, a coating liquid containing an ultraviolet curable resin is applied on the transparent resin film, and ultraviolet rays are applied from the transparent resin film side in a state where the formed ultraviolet curable resin layer is in close contact with the uneven surface of the mold. Irradiate to cure the UV curable resin, and then transfer the shape of the mold to the UV curable resin by peeling the transparent resin film on which the cured UV curable resin layer is formed from the mold. . The kind in particular of ultraviolet curable resin is not restrict | limited, For example, what was mentioned above can be used. Further, instead of the ultraviolet curable resin, a visible light curable resin that can be cured with visible light having a wavelength longer than that of ultraviolet light may be used by appropriately selecting a photoinitiator.

  The thickness of the hard coat layer is, for example, 2 to 30 μm, preferably 3 to 30 μm. When the thickness of the hard coat layer is less than 2 μm, sufficient hardness cannot be obtained, and the surface tends to be easily damaged. When the thickness is greater than 30 μm, the hard coat layer is easily broken and is prevented by hardening shrinkage of the hard coat layer. There is a tendency that the dazzling film curls and the productivity decreases.

  The antiglare film is preferably imparted with haze by the hard coat layer, but may be imparted with the formation of the hard coat layer by dispersing inorganic or organic fine particles in the transparent resin film. Further, as the antiglare film, it is possible to use a transparent resin film that does not have a hard coat layer and in which inorganic or organic fine particles are dispersed. In these cases, the above-mentioned inorganic or organic fine particles can be used. The thickness of the transparent resin film in which inorganic or organic fine particles are dispersed is preferably about 20 to 200 μm, more preferably about 20 to 120 μm.

  In addition to antiglare treatment (haze imparting treatment), the transparent resin film may be subjected to surface treatment such as antistatic treatment, and a coating layer made of a liquid crystalline compound or a high molecular weight compound thereof is formed. Also good. However, you may provide an antistatic function to other parts of roll-shaped polarizing plates, such as an adhesive layer and an adhesive bond layer, instead of or together with a transparent resin film.

(2) Non-orientable film The second roll-shaped polarizing plate has a haze value of 0.5% or less between the second polarizing film made of polyvinyl alcohol resin and the second pressure-sensitive adhesive layer. In addition, a non-oriented film made of a polyolefin resin having an in-plane retardation value R ₀ of less than 30 nm may be provided. By providing the non-oriented film, the front and back asymmetry of the polarizing plate can be reduced and curling can be more effectively suppressed.

  The non-oriented film preferably has a Gurley bending resistance measured in accordance with JIS L 1096 of 350 mgf or less, more preferably 200 mgf or less, and even more preferably 150 mgf or less. Thus, since the rigidity of the obtained 2nd roll-shaped polarizing plate is reduced by using a non-orientation film with small bending resistance, the handling property at the time of bonding to a liquid crystal cell is improved. Can do. Moreover, when the non-oriented film is made of a polyolefin resin, light leakage in the display area of the obtained liquid crystal display device can be improved because the photoelastic coefficient of the polyolefin resin is small.

The non-oriented film preferably has an in-plane retardation value R ₀ of less than 30 nm, more preferably less than 15 nm. When the in-plane retardation value R ₀ is 30 nm or more, light leakage during black display increases when applied to a liquid crystal display device, and the reduction in contrast ratio becomes significant.

The thickness direction retardation R _th for unoriented films, depending on the thickness direction retardation R _th of a liquid crystal cell combined, to compensate for it, is appropriately selected.

  The angle θ formed by the MD (flow direction, that is, the longitudinal direction) of the non-oriented film and the optical axis is preferably ± 5 ° or less, and more preferably ± 3 ° or less. When the angle θ is larger than ± 5 °, when applied to a liquid crystal display device, light leakage at the time of black display becomes large, and the reduction in contrast ratio becomes remarkable.

Further, the transmittance parameter calculated from the in-plane retardation value R ₀ and the angle θ between the MD and the optical axis is preferably 0.03 or less, more preferably 0.007 or less, and still more preferably. Is 0.001 or less. When the transmittance parameter is larger than 0.03%, when applied to a liquid crystal display device, light leakage at the time of black display becomes remarkable, and a reduction in contrast ratio becomes remarkable. The transmittance parameter is the following formula:
Transmission parameter ^{= sin 2 2θ × sin 2 (} π × R 0/590)
Defined by

  The non-oriented film is preferably made of a polypropylene resin or a cyclic polyolefin resin. As described above, by using a polypropylene resin or a cyclic polyolefin resin having a low elastic modulus, a film having a low Gurley stiffness is easily obtained. Moreover, since the polypropylene resin film and the cyclic polyolefin resin film have small moisture permeability, the durability of the obtained polarizing plate in a high-humidity environment can be improved.

  As the polyolefin resin constituting the non-oriented film, the polyolefin resins listed as the resins that can constitute the protective film made of the transparent resin may be used alone or in combination of two or more kinds. Good. These polyolefin resins can also be used after any suitable polymer modification. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, stereoregularity control, and reaction between different polymers. Modification including mixing including the case involving, for example, ethylene-propylene copolymer resin and the like.

In addition, the non-oriented film is obtained by stretching or shrinking an unstretched film obtained by filming these resins in MD (flow direction) and / or TD (direction perpendicular to the flow direction), and in-plane. The phase difference value R ₀ may be less than 30 nm.

  As the non-oriented film made of polypropylene resin or cyclic polyolefin resin, those described for the protective film made of the transparent resin can be used as long as the haze value is 0.5% or less.

  Hereinafter, a method for producing a polypropylene resin film having a haze value of 0.5% or less will be described. Although it does not specifically limit as a method for suppressing the haze value of a polypropylene resin film to 0.5% or less, The method of the following (a)-(e) is illustrated. In order to set the haze value of the polypropylene resin film to 0.5% or less, the following methods (a) to (d) may be appropriately combined.

(A) a method using a polypropylene resin comprising a random copolymer of propylene and another unsaturated hydrocarbon,
(A) a method of adding a nucleating agent to a polypropylene resin,
(C) A method of forming a polypropylene resin film by increasing the cooling efficiency of a metal cooling roll (casting roll) and touch roll during extrusion molding,
(D) A method of reducing the film thickness of the molten sheet.

(A) Method using a random copolymer Examples of random copolymers of propylene and other unsaturated hydrocarbons include propylene / ethylene random copolymers, propylene / 1-butene random copolymers, and propylene / 1-hexene. A random copolymer, a propylene / ethylene / 1-octene random copolymer, a propylene / ethylene / 1-butene random copolymer, and the like can be mentioned. Among them, a copolymer with ethylene is particularly preferable.

  The content of other unsaturated hydrocarbon units in the random copolymer is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, and further preferably 3 to 7% by weight. preferable. When a copolymer of two or more types of unsaturated hydrocarbon and propylene is used, the total content of units derived from all unsaturated hydrocarbons contained in the copolymer is within the above range. preferable. By adjusting the content of other unsaturated hydrocarbon units to 1% by weight or more, processability and transparency can be significantly improved. On the other hand, when the content of other unsaturated hydrocarbon units exceeds 20% by weight, the melting point of the polypropylene resin is lowered, and the heat resistance tends to be lowered.

(A) Method by addition of nucleating agent The nucleating agent may be either an inorganic nucleating agent or an organic nucleating agent. Examples of the inorganic nucleating agent include talc, clay, calcium carbonate and the like. Examples of the organic nucleating agent include metal salts such as aromatic carboxylic acid metal salts and aromatic phosphoric acid metal salts, high-density polyethylene, poly-3-methylbutene-1, polycyclopentene, and polyvinylcyclohexane. It is done. Among these, organic nucleating agents are preferable, and the above metal salts and high density polyethylene are more preferable. Moreover, 0.01-3 weight% is preferable and, as for the addition amount of the nucleating agent with respect to propylene-type resin, 0.05-1.5 weight% is more preferable. A plurality of nucleating agents may be used in combination.

  The method for adding the nucleating agent is not particularly limited as long as it can be uniformly dispersed. For example, in the polymerization step for producing a polypropylene resin, nucleation is performed in the polymerization reaction mixture during the polymerization reaction or immediately after the completion of the polymerization reaction. What is necessary is just to add an agent. The nucleating agent may be added as a solution dissolved in a solvent, may be added as a dispersant pulverized in a powder form so that it can be easily dispersed, or may be added in a molten state by heating. Good.

(C) Method of rapid cooling in extrusion molding This method is performed by lowering the surface temperature of the cooling roll and the touch roll when the molten sheet of polypropylene resin is sandwiched between the cooling roll and the touch roll and solidified by cooling. This is a method of rapidly cooling the sheet. As described above, the surface temperature of both rolls is preferably 0 ° C. or higher and 30 ° C. or lower.

(D) Method of reducing the film thickness This method is a method of reducing the film thickness of the molten sheet in extrusion molding, thereby accompanying the haze reduction effect by thinning and the improvement of cooling efficiency by the cooling roll and touch roll. A haze reduction effect is obtained. The extrusion amount of the molten sheet can be arbitrarily selected.

  The lamination and lamination of the antiglare film and / or the biaxial retardation film to the second polarizing film may be the same as the method described for the first roll-shaped polarizing plate. When an adhesive layer is formed on both surfaces of the second polarizing film, the adhesive forming these adhesive layers may be the same or different. Moreover, the adhesive used for preparation of the first roll-shaped polarizing plate and the adhesive used for preparation of the second roll-shaped polarizing plate may be the same or different.

  The first roll-shaped polarizing plate and the second roll-shaped polarizing plate as described above are a roll-to-cell type bonding process as a set of roll-shaped polarizing plates (that is, a roll-shaped polarizing plate is used as a liquid crystal cell). It is used for the process of pasting and is made into a liquid crystal panel. According to the set of roll-shaped polarizing plates of the present invention, the first roll-shaped polarizing plate and the second roll-shaped polarizing plate each have a width corresponding to the long side and the short side of the liquid crystal cell to be bonded. Therefore, a polarizing plate having a size corresponding to the liquid crystal cell can be obtained simply by cutting the length corresponding to the short side and the long side of the liquid crystal cell. Moreover, since the 1st and 2nd roll-shaped polarizing plate has an absorption axis in the long side direction, it is bonding with a polarizing plate and a liquid crystal cell with the outstanding axial precision by bonding in a roll-to-cell. It can be performed. Thereby, it is possible to obtain a liquid crystal panel in which light leakage is remarkably reduced and display performance such as front contrast is remarkably improved.

<Method for producing roll-shaped polarizing plate set>
The roll-shaped polarizing plate set of the present invention includes a first roll-shaped polarizing plate production process including the following steps (a) to (c) and a second roll shape including the following steps (d) to (f). It can produce suitably by the method including a polarizing plate manufacturing process.

(A) A protective film made of a transparent resin, a first polarizing film, a biaxial retardation film, a first pressure-sensitive adhesive layer, and a first release film in this order, and a first polarizing film A first original fabric in which a film is laminated so that the absorption axis of the film is parallel to the long side direction (the long side direction of the first polarizing plate long original fabric) to produce a first polarizing plate long original fabric Production process,
(B) a first slitting step of obtaining a long polarizing plate by cutting the first polarizing plate long raw material obtained in the first raw fabric producing step so as to have a width corresponding to the long side of the liquid crystal cell;
(C) The 1st polarizing plate winding-up process which winds up the long polarizing plate obtained at a 1st slit process in roll shape.

(D) The anti-glare film, the second polarizing film, the second pressure-sensitive adhesive layer, and the second release film in this order, and the absorption axis of the second polarizing film is the long side direction (first A second original film production step of producing a second original film of the long polarizing plate by laminating it in a direction parallel to the long side direction of the long polarizing film of the polarizing plate 2),
(E) a second slitting step of obtaining a long polarizing plate by cutting the second polarizing plate long raw material obtained in the second raw fabric producing step so as to have a width corresponding to the short side of the liquid crystal cell;
(F) The 2nd polarizing plate winding-up process which winds up the long polarizing plate obtained at a 2nd slit process in roll shape.

  When a non-oriented film is used, the second roll-shaped polarizing plate raw material is an antiglare film, a second polarizing film, a non-oriented film, a second pressure-sensitive adhesive layer, and a second release film. Are laminated in this order.

  Bonding and laminating of various films (including the pressure-sensitive adhesive layer) performed in the first original fabric producing step (a) and the second original fabric producing step (d) may be performed simultaneously or sequentially. Also good. Bonding and laminating of these films can be performed by, for example, a roll-to-roll method using a roll film.

  In the first slit step (b), the first polarizing plate original is a liquid crystal parallel to the absorption axis of the first polarizing film (parallel to the long side direction of the first polarizing plate original). It is slit with a width corresponding to the short side of the cell. In the second slitting step (e), the second polarizing plate long original fabric is liquid crystal parallel to the absorption axis of the second polarizing film (parallel to the long side direction of the second polarizing plate long original fabric). It is slit with a width corresponding to the short side of the cell. The “width corresponding to the short side or long side of the liquid crystal cell” is as described above.

  In the first slitting step (b) and the subsequent first polarizing plate winding step (c), the length of slitting while unwinding and slitting the first polarizing plate long roll wound up in a roll shape A method of winding a long polarizing plate into a roll shape, slitting without winding up the first polarizing plate long raw material that is not wound into a roll obtained in the first raw fabric preparation step, and the slit length There is a method of winding a long polarizing plate into a roll shape, and any of them can be adopted. The same applies to the second slitting step (e) and the subsequent second polarizing plate winding step (f). Although the winding direction of the polarizing plate is not particularly limited by the slit slit in the first polarizing plate winding step (c) and the second polarizing plate winding step (f), for example, the first and second release films It can be wound up so that the side is inside.

  The order in particular of the 1st roll-shaped polarizing plate manufacturing process and the 2nd roll-shaped polarizing plate manufacturing process is not restrict | limited, You may carry out simultaneously in parallel, and may carry out sequentially.

  According to the method for producing a set of roll-shaped polarizing plates of the present invention, the first roll-shaped polarizing plate is slit-processed with a width corresponding to the long side of the liquid crystal cell, and the second roll-shaped polarizing plate is short of the liquid crystal cell. Since slit processing is performed with a width corresponding to the side, by using them as a roll-shaped polarizing plate as a set, it is possible to correspond to the liquid crystal cell only by cutting each to the short side of the liquid crystal cell and the length corresponding to the long side. A polarizing plate having the size to be obtained can be obtained. Moreover, since the first and second roll-shaped polarizing plates have an absorption axis in the long side direction, the axial accuracy at the time of bonding between the polarizing plate and the liquid crystal cell is improved, and light leakage is significantly reduced. A liquid crystal panel excellent in display performance such as front contrast can be obtained. Furthermore, in the set of roll-shaped polarizing plates obtained, the absorption axis of one roll-shaped polarizing plate is parallel to the long side of the liquid crystal cell, and the absorption axis of the other roll-shaped polarizing plate is parallel to the short side of the liquid crystal cell. Therefore, the long side direction of both roll-shaped polarizing plates (or polarizing plates obtained by cutting them into a predetermined shape) is parallel to the liquid crystal cell transport direction in the liquid crystal panel manufacturing process. The absorption axes of the respective polarizing plates can be made orthogonal to each other only by pasting.

<Manufacturing method of liquid crystal panel>
The present invention uses the above-mentioned set of roll-shaped polarizing plates, and bonds a first polarizing plate (a polarizing plate cut into a predetermined shape from the first roll-shaped polarizing plate) on the back side of the liquid crystal cell, A method for producing a liquid crystal panel by bonding a second polarizing plate (a polarizing plate cut into a predetermined shape from a second roll-shaped polarizing plate) to the viewing side of the film is provided. The manufacturing method of the liquid crystal panel of the present invention includes a first transporting step of a liquid crystal cell for transporting the liquid crystal cell so that the short side direction is the flow direction; a first polarizing plate comprising the following steps (A) to (D) Supply bonding process; 2nd conveyance process of the liquid crystal cell which conveys a liquid crystal cell so that the long side direction turns into a flow direction; and the 2nd polarizing plate supply bonding provided with following process (E)-(H). Including a process. As a result, a liquid crystal panel is obtained in which the first polarizing plate is laminated on one surface of the liquid crystal cell and the second polarizing plate is laminated on the other surface.

(A) Of the set of roll-shaped polarizing plates, a long polarizing plate is unwound from the first roll-shaped polarizing plate so as to face the back side of the liquid crystal cell supplied in the first transporting step of the liquid crystal cell. First polarizing plate unwinding step,
(B) First polarizing plate cutting to obtain a first polarizing plate by cutting the long polarizing plate after being unwound in the first polarizing plate unwinding step into a length corresponding to the short side of the liquid crystal cell Process,
(C) The long polarizing plate unwound in the first polarizing plate unwinding step or the polarizing plate (first polarizing plate) cut in the first polarizing plate cutting step in the first transport step of the liquid crystal cell A first polarizing plate alignment step that matches the position where the liquid crystal cell to be conveyed is to be bonded;
(D) A long polarizing plate or a cut polarizing plate (first polarizing plate) after passing through the first polarizing plate alignment step is placed on the back side of the liquid crystal cell that is transported in the first transporting step of the liquid crystal cell. The 1st polarizing plate bonding process to bond.

(E) Of the set of roll-shaped polarizing plates, a long polarizing plate is unwound from the second roll-shaped polarizing plate so as to be directed to the viewing side of the liquid crystal cell conveyed in the second conveying step of the liquid crystal cell. Second polarizing plate unwinding step,
(F) Second polarizing plate cutting to obtain a second polarizing plate by cutting the long polarizing plate after being unwound in the second polarizing plate unwinding step into a length corresponding to the long side of the liquid crystal cell Process,
(G) The long polarizing plate unwound in the second polarizing plate unwinding step or the polarizing plate (second polarizing plate) cut in the second polarizing plate cutting step in the second transport step of the liquid crystal cell A second polarizing plate alignment step that matches the position where the liquid crystal cell to be conveyed is to be bonded;
(H) The long polarizing plate or the cut polarizing plate (second polarizing plate) after passing through the second polarizing plate alignment step is placed on the viewing side of the liquid crystal cell that is transported in the second transporting step of the liquid crystal cell. The 2nd polarizing plate bonding process to bond.

  FIG. 1 is a schematic view showing an example of a method for producing a liquid crystal panel of the present invention. Specifically, the liquid crystal panel is suitably used for the first transport step, the first polarizing plate supply bonding step, and the implementation of these steps. 1 schematically shows an apparatus that can be used. As shown in FIG. 1, the first polarizing plate 20 is bonded to the back side of the liquid crystal cell 40 using a first conveying step 64 of the liquid crystal cell 40 using a belt conveyor or the like; Then, the long polarizing plate 72 is unwound from the first roll-shaped polarizing plate 71. (A) First polarizing plate unwinding step 60; The unwinding long polarizing plate 72 is cut using the cutting means 62a. Then, the first polarizing plate 20 is obtained by cutting to a length corresponding to the short side of the liquid crystal cell 40. (B) First polarizing plate cutting step 62; unrolled long polarizing plate 72 or first polarized light The first polarizing plate 20 obtained by cutting in the plate cutting step 62 is aligned with the position where the conveyed liquid crystal cell 40 is to be bonded by position control using the sensor 61a or the like. (C) First polarization Plate alignment step 61; long polarized light after passing through the first polarizing plate alignment step 61 72 or the first polarizing plate 20 obtained by cutting is bonded to the back side of the conveyed liquid crystal cell 40 using a bonding roll 63a or the like (D) through a first polarizing plate bonding step 63. This is done to obtain the liquid crystal cell 41 having the first polarizing plate 20 bonded to one side.

  (B) As the cutting means 62a used in the first polarizing plate cutting step 62, for example, a laser, a cutting blade, or other known cutting means can be used. In the cutting step, as shown in FIG. 1, only the other layers are cut without cutting the first release film 80 disposed on the outermost surface of the long polarizing plate 72. It is preferable to perform “half-cut”. Thereby, the 1st release film 80 can be utilized as a conveyance medium of the 1st polarizing plate 20 cut | judged by the predetermined shape. At this time, by applying an appropriate tension to the first release film 80, the curling of the first polarizing plate 20 cut into a predetermined shape can be suppressed.

  However, as shown in FIG. 2, when a separate release film collection film 76 is used as the transport medium for the first polarizing plate 20 cut into a predetermined shape, it is not a “half cut” but a long one. All the layers constituting the long polarizing plate 72 may be cut. In such a case, in the release film collection step 65 described later, the release film collection film 76 is collected together with the first release film 80 peeled from the cut polarizing plate. As the release film collection film 76, a film having adhesiveness with respect to the first release film 80 is used.

  (C) In the first polarizing plate alignment step 61, the long polarizing plate 72 obtained by the sensor 61 a or the long polarizing plate 72 or the first polarizing plate 20 and the liquid crystal cell 40 based on the relative positional relationship information. The polarizing plate 72 or the first polarizing plate 20 may be fixed, and the position of the liquid crystal cell 40 may be adjusted for alignment, or the liquid crystal cell 40 may be fixed and the long polarizing plate 72 or the first polarizing plate. You may align by adjusting the position of the board 20. In the latter case, from the viewpoint of handling properties, (B) the first polarizing plate cutting step 62 is performed before the (C) first polarizing plate positioning step 61, and the first polarizing plate 20 cut into a predetermined shape is used. It is preferable to perform alignment in a state.

  (D) In the first polarizing plate bonding step 63, the bonding of the long polarizing plate 72 or the first polarizing plate 20 obtained by cutting to the liquid crystal cell 40 is as shown in FIG. After releasing the first release film 80 from the aligned long polarizing plate 72 or the first polarizing plate 20 using the release film peeling device 81 (release film recovery step 65), the film was exposed. It can carry out by laminating | stacking on the liquid crystal cell 40 by the 1st adhesive layer side, and pressing using the bonding roll 63a. The release film collecting step 65 includes a step of winding up the peeled first release film 80.

  Here, (B) first polarizing plate cutting step 62, (C) first polarizing plate alignment step 61, and (D) first polarizing plate bonding step, following (A) first polarizing plate unwinding step 60. The order of 63 is not particularly limited, and can be performed in the order of (B) → (C) → (D) or (C) → (B) → (D), for example. Or as FIG. 3 shows, it can also carry out in order of (C)-> (D)-> (B). In the apparatus performed in this order, as shown in FIG. 3, the sensor 61a, the cutting means 62a, the bonding roll 63a, and the like move the position of each component in the apparatus by expansion and contraction as necessary. The elastic part 75 which can be provided can be provided. Even if each component is a fixed type and a space for performing any one of the steps cannot be secured, the position of the component can be moved after the step by providing the expansion / contraction part 75. Therefore, a space for performing the next step can be secured.

  From the viewpoint of handling properties, (B) the first polarizing plate cutting step 62 is performed before the (C) first polarizing plate alignment step 61, and the first polarizing plate 20 is cut into a predetermined shape. It is preferable to combine them.

  When performing in the order of (B) → (C) → (D), the cutting timing of the long polarizing plate 72 in the step (B) and the alignment timing in the step (C) are not particularly limited and are shown in FIG. As shown in FIG. 4, the alignment of the step (B) may be performed immediately before the step (C), or as shown in FIG. 4, there is a fixed interval between the steps (B) and (C). An interval may be provided. In the latter case, it is possible to prevent the alignment accuracy in the step (C) from deteriorating due to the displacement of the polarizing plate during cutting.

  Bonding of the second polarizing plate 30 (not shown in FIG. 1) to the viewing side of the liquid crystal cell 40 (second polarizing plate supply bonding step) is also performed on the first polarizing plate 20 to the liquid crystal cell 40. It can carry out like the bonding (1st polarizing plate supply bonding process). 1 to 4 and FIGS. 5 to 6 to be described later show an example in which the first polarizing plate 20 is first bonded to the liquid crystal cell 40, but after the second polarizing plate 30 is bonded, Of course, one polarizing plate 20 may be bonded.

  FIG. 5 is a schematic view showing an example of a method for manufacturing a liquid crystal panel according to the present invention. Specifically, the first polarizing plate 20 is bonded to the back side of the liquid crystal cell 40, and the first side is attached to one side. An example in which the liquid crystal panel 94 is manufactured by obtaining the liquid crystal cell 94 including the polarizing plate 20 and then bonding the second polarizing plate 30 to the viewing side of the liquid crystal cell 40 is shown. In FIG. 5, (A) the first polarizing plate unwinding step 60 and (E) the second polarizing plate unwinding step 60 ′ are (A) the first polarizing plate unwinding step 60 in the first polarizing plate unwinding step 60. And the flow direction of the long polarizing plate 72 unwound from (2) the long polarizing plate 72 ′ unwound from the second roll-shaped polarizing plate 71 ′ in the second polarizing plate unwinding step 60 ′. The flow direction is perpendicular to each other. If the flow directions are orthogonal, the absorption axes of the polarizing plates bonded to both surfaces of the liquid crystal cell are inevitably orthogonal to each other, which is necessary in the method shown in FIG. 6 described later. The liquid crystal cell turning step 92 is omitted, and the first polarizing plate supply bonding step and the second polarizing plate supply bonding step can be continuously performed only through the upside down step 91, thereby improving the production efficiency. Can be made. In addition, a 1st polarizing plate supply bonding process and a 2nd polarizing plate supply bonding process may be performed in the same place, and may be performed in a different place.

  Moreover, (A) 1st polarizing plate unwinding process 60 and (E) 2nd polarizing plate unwinding process 60 'are 1st in (A) 1st polarizing plate unwinding process 60, as FIG. 6 shows. The flow direction of the long polarizing plate 72 unwound from the roll-shaped polarizing plate 71, and (E) the length unwound from the second rolled polarizing plate 71 ′ in the second polarizing plate unwinding step 60 ′ It may be performed so that the flow direction of the long polarizing plate 72 ′ is parallel. In such a case, normally, as shown in FIG. 6, the liquid crystal cell 94 including the first polarizing plate 20 on one side after the upside down step 91 is used in the next second polarizing plate supply bonding step. A turning step 92 for turning in the flow direction is provided. As shown in FIG. 6, it is preferable that the process line of the 1st polarizing plate supply bonding process and the process line of the 2nd polarizing plate supply bonding process are arrange | positioned up and down from a space-saving viewpoint.

  In any of the above liquid crystal panel manufacturing methods, the supply of the long polarizing plates 72 and 72 ′ in (A) the first polarizing plate unwinding step 60 and (E) the second polarizing plate unwinding step 60 ′. By performing from both sides of the liquid crystal cell 40, the upside down process 91 can be omitted. In FIGS. 5 and 6, the long polarizing plate 72 unwound in the first polarizing plate unwinding step 60 and the long polarizing plate 72 ′ unwound in the second polarizing plate unwinding step 60 ′ are both Although the liquid crystal cells 40 and 94 are supplied from the upper side and are bonded, the upper and lower sides are reversed, and the long polarizing plates 72 and 72 ′ are supplied from the lower side of the liquid crystal cells 40 and 94, respectively. Of course, it is also possible to make it stick.

  A defect inspection step for the polarizing plate may be provided before or after any of the steps (A) to (H) or in parallel with any of these steps. The defect inspection method is not particularly limited. For example, a method of detecting an image from an image obtained by irradiating transmitted light or reflected light on both surfaces of a polarizing plate, and detecting the defect from the obtained image, a CCD is used. An image is taken between the camera and the inspection object so as to be crossed Nicols with the absorption axis of the polarizing plate to be inspected (sometimes referred to as 0 degree crossing), and an image is taken. The inspection polarizing plate is placed between the CCD camera and the inspection object, and the absorption axis of the inspection polarizing plate is larger than a predetermined angle (for example, greater than 0 degree) with respect to the absorption axis of the polarizing plate to be inspected. A method of detecting a defect from an image obtained by taking an image by arranging (sometimes referred to as an x-degree cross) so as to be within a range of 10 degrees or less may be mentioned. Note that a known method can be applied to an image processing algorithm for detecting a defect from the obtained image. For example, the defect can be detected by density determination by binarization processing.

  Among the above, in the method of taking an image by irradiating transmitted light, foreign matter inside the polarizing plate can be detected. In the method of taking an image by irradiating reflected light, foreign matter adhering to the surface of the polarizing plate can be detected. In the method of taking an image by arranging a polarizing plate for inspection at 0 degree cross, mainly foreign matter or dirt adhering to the surface and internal foreign matter can be detected as bright spots. In the method in which a polarizing plate for inspection is arranged with an x degree cross and an image is taken, this mainly occurs at the interface between the polarizing film and the protective film / antiglare film / biaxial retardation film / non-oriented film. Local uneven defects, so-called nicks, can be detected.

  When the defect inspection step is provided, based on the defect information obtained in the defect inspection step, a cutting step (steps (B) and (F), an alignment step (steps (C) and (G)) or In the bonding step (steps (D) and (H)), it is preferable that the film is cut, aligned or bonded while avoiding the defects so as not to include the defects in the polarizing plate region bonded to the liquid crystal cell. From the viewpoint of yield, the defect inspection step is preferably performed before the first and second polarizing plate bonding steps (D) and (H) to eliminate the defect portion.

  Moreover, in the manufacturing method of the liquid crystal panel of this invention, after bonding a polarizing plate on both surfaces of a liquid crystal cell, it is preferable to include the fault inspection process of the liquid crystal panel which test | inspects a liquid crystal panel. Examples of the defect inspection method include a method of irradiating reflected light on both surfaces of the liquid crystal panel to take an image and detecting a defect from the obtained image. As another method, a method of installing an inspection polarizing plate between the CCD camera and the inspection object is also exemplified. Note that a known method can be applied to an image processing algorithm for detecting a defect from the obtained image. For example, the defect can be detected by density determination by binarization processing.

  Furthermore, a determination process for determining whether or not the liquid crystal panel is non-defective may be provided based on the defect information obtained in the defect inspection process of the liquid crystal panel. The liquid crystal panel that has been determined to be non-defective is used in a mounting process for a liquid crystal display device, which is the next process. On the other hand, when a defective product is determined, a rework process (a step of removing the polarizing plate from the liquid crystal cell) is performed, a polarizing plate is newly bonded, and then inspected. In the case of non-defective product determination, the process proceeds to the mounting process, and in the case of defective product determination, the rework process is performed again or is discarded.

  The manufacturing method of the liquid crystal panel of this invention shown above can implement the 1st polarizing plate supply bonding process and the 2nd polarizing plate supply bonding process with the continuous manufacturing line, and is excellent in manufacturing efficiency. In order to obtain a high-quality liquid crystal panel, each step included in the method for producing a liquid crystal panel of the present invention is preferably performed inside an isolation structure with a high cleanliness.

  The liquid crystal cell used in the present invention is not particularly limited, but is preferably a VA mode liquid crystal cell. When a liquid crystal panel is formed using a VA mode liquid crystal cell, the absorption axes of the polarizing plates are usually orthogonal to each other, and these absorption axes are in the long side direction or short side direction of the rectangular liquid crystal cell. Therefore, the present invention uses the first and second roll-shaped polarizing plates having an absorption axis in the long side direction and a width corresponding to the long side or the short side of the liquid crystal cell. The production method can be preferably used.

<Liquid crystal panel and liquid crystal display device>
FIG. 7 is a schematic cross-sectional view showing an example of a basic layer configuration of a liquid crystal panel manufactured by the method of the present invention and a liquid crystal display device to which the liquid crystal panel is applied. The liquid crystal display device shown in FIG. 7 includes a backlight 10, a light diffusing plate 50, a liquid crystal cell 40, and a first polarizing plate 20 as a back side polarizing plate bonded to one surface of the liquid crystal cell 40. And the liquid crystal panel 96 which consists of the 2nd polarizing plate 30 as the front side polarizing plate bonded by the other surface of the liquid crystal cell 40 is arrange | positioned in this order. The first polarizing plate 20 has a configuration in which the first polarizing film 21 is sandwiched between a biaxial retardation film 23 and a protective film 25 made of a transparent resin, and the biaxial retardation film 23 is It is bonded to the liquid crystal cell 40 via the first pressure-sensitive adhesive layer 27 so as to face the liquid crystal cell 40. The second polarizing plate 30 has a configuration in which the second polarizing film 31 is sandwiched between the non-oriented film 33 and the antiglare film 34, and the non-oriented film 33 is attached to the liquid crystal cell 40. It is bonded to the liquid crystal cell 40 through the second pressure-sensitive adhesive layer 37 so as to face each other. In this example, the antiglare film 34 is composed of a transparent resin film 35 and a hard coat layer 36 having a fine uneven shape on the surface laminated thereon. In the liquid crystal display device of the present invention shown in FIG. 7, the liquid crystal panel 96 is arranged so that the first polarizing plate 20 that is the back side polarizing plate is on the backlight side, that is, the protective film 25 is the light diffusing plate 50. It arrange | positions so that it may oppose.

  The second polarizing plate 30 may not have the non-oriented film 33 interposed between the second polarizing film 31 and the second pressure-sensitive adhesive layer 37.

  In the present invention, the long polarizing plate drawn out from the roll-shaped polarizing plate is subjected to the manufacturing process of the liquid crystal panel without being cut into single sheets, so that curling is less likely to occur even when the polarizing plate is asymmetrical on the front and back sides. The first polarizing plate 20 cut into a predetermined shape from the first roll-shaped polarizing plate and the second polarizing plate 30 cut into a predetermined shape from the second roll-shaped polarizing plate are bonded to the liquid crystal cell 40. At this time, it is difficult to cause problems such as entrapment of bubbles and foreign matters. Moreover, since the 1st polarizing plate 20 and the 2nd polarizing plate 30 are bonded to the liquid crystal cell 40 by the roll-to-cell system using the set of roll-shaped polarizing plates, the liquid crystal panel obtained is a polarizing plate and The axial accuracy of the bonding with the liquid crystal cell 40 is excellent, and the occurrence of defects due to contamination in the apparatus can be suppressed, thereby light leakage is remarkably reduced and display performance such as front contrast is remarkably improved. An improved liquid crystal display device can be obtained. Furthermore, since a biaxial retardation film made of a polyolefin resin having low moisture permeability is used, the moisture and heat resistance of the obtained liquid crystal panel and liquid crystal display device can be improved.

  The light diffusing plate 50 is an optical member having a function of diffusing light from the backlight 10, for example, a particle obtained by dispersing particles as a light diffusing agent in a thermoplastic resin to impart light diffusibility, thermoplasticity The surface of the resin film may be uneven to provide light diffusibility, or the resin film may be provided with a coating layer of a resin composition in which particles are dispersed on the surface of the thermoplastic resin film. . The thickness can be about 0.1-5 mm.

  Between the light diffusing plate 50 and the liquid crystal panel 96, a prism sheet (also called a condensing sheet, for example, “BEF” manufactured by 3M, etc.), a brightness enhancement sheet (the reflective polarization described above). It is also possible to arrange a sheet or film exhibiting other optical functionality, such as a light diffusion sheet, which is the same as the film (such as “DBEF”). Two or more sheets or films showing other optical functionalities can be arranged as required. Further, as the light diffusion plate 50, for example, a light diffusion plate such as a laminated integrated product of a prism sheet having a cylindrical shape on the surface and a light diffusion plate (for example, one described in Japanese Patent Application Laid-Open No. 2006-284597). It is also possible to use an optical sheet in which other functions are combined with each other.

10 Backlight,
20 first polarizing plate,
21 1st polarizing film,
23 Biaxial retardation film,
25 Protective film made of transparent resin,
27 first adhesive layer,
30 Second polarizing plate,
31 Second polarizing film,
33 non-oriented film,
34 Anti-glare film,
35 Transparent resin film,
36 Hard coat layer,
37 second adhesive layer,
40 liquid crystal cell,
41 A liquid crystal cell having a first polarizing plate bonded on one side,
50 light diffusion plate,
60 First polarizing plate unwinding step,
60 '2nd polarizing plate unwinding process,
61 1st polarizing plate alignment process,
61 '2nd polarizing plate alignment process,
61a sensor,
62 1st polarizing plate cutting process,
62 '2nd polarizing plate cutting process,
62a cutting means,
63 1st polarizing plate bonding process,
63 '2nd polarizing plate bonding process,
63a bonding roll,
64 The first transfer step of the liquid crystal cell,
64 '2nd conveyance process of liquid crystal cell,
65, 65 ′ release film recovery process,
71 1st roll-shaped polarizing plate,
71 '2nd roll-shaped polarizing plate,
72 A long polarizing plate unwound from the first roll-shaped polarizing plate,
72 ′ a long polarizing plate unwound from the second roll-shaped polarizing plate,
75 telescopic part,
76 Release film collection film,
80 the first release film,
81 release film peeling device,
91 Upside down process,
92 swivel process,
94 A liquid crystal cell comprising a first polarizing plate on one side,
96 LCD panel.

Claims (6)

It is a set of a roll-shaped polarizing plate comprising a first roll-shaped polarizing plate for bonding to the back side of the liquid crystal cell and a second roll-shaped polarizing plate for bonding to the viewing side of the liquid crystal cell. And
The first roll-shaped polarizing plate is
A protective film made of transparent resin;
A first polarizing film made of a polyvinyl alcohol-based resin;
The in-plane retardation value is in the range of 30 to 200 nm, the thickness direction retardation value is in the range of 100 to 350 nm, and a biaxial retardation film made of polyolefin resin,
A first adhesive layer;
A first release film;
Are formed in this order, and the absorption axis of the first polarizing film is parallel to the long side direction of the long polarizing plate, and the long side of the liquid crystal cell Wound into a roll with a corresponding width;
The second roll-shaped polarizing plate is
An antiglare film having a haze value in the range of 0.1 to 45%;
A second polarizing film made of a polyvinyl alcohol-based resin;
A second adhesive layer;
A second release film;
Are formed in this order, and the absorption axis of the second polarizing film is parallel to the long side direction of the long polarizing plate, and the short side of the liquid crystal cell Rolled into a roll with a corresponding width,
A set of roll-shaped polarizing plates.   The second roll-shaped polarizing plate has a haze value of 0.5% or less and an in-plane retardation value of less than 30 nm between the second polarizing film and the second pressure-sensitive adhesive layer. The set of the roll-shaped polarizing plate of Claim 1 which has a non-orientation film which consists of a certain polyolefin-type resin. Manufactures a set of roll-shaped polarizing plates comprising a first roll-shaped polarizing plate for bonding to the back side of the liquid crystal cell and a second roll-shaped polarizing plate for bonding to the viewing side of the liquid crystal cell How to do;
A protective film made of a transparent resin, a first polarizing film made of a polyvinyl alcohol-based resin, an in-plane retardation value in the range of 30 to 200 nm, a thickness direction retardation value in the range of 100 to 350 nm, a polyolefin A biaxial retardation film made of a resin, the first pressure-sensitive adhesive layer, and the first release film in this order, and a direction in which the absorption axis of the first polarizing film is parallel to the long side direction; A first raw material production step of producing a first polarizing plate long original material by laminating to be,
A first slitting step of cutting the first polarizing plate long original fabric obtained in the first original fabric producing step so as to have a width corresponding to the long side of the liquid crystal cell;
A first polarizing plate winding step comprising: winding a long polarizing plate obtained in the first slit step into a roll shape; and a haze value of 0.1 to 45% The antiglare film in the range, the second polarizing film made of polyvinyl alcohol resin, the second pressure-sensitive adhesive layer, and the second release film in this order, and the second polarizing film A second raw material production step of producing a second polarizing plate long raw material by laminating so that the absorption axis is parallel to the long side direction;
A second slitting step of cutting the second polarizing plate long original fabric obtained in the second original fabric producing step so as to have a width corresponding to the short side of the liquid crystal cell;
A second polarizing plate winding step including a second polarizing plate winding step of winding the long polarizing plate obtained in the second slit step into a roll shape. Method. A method for producing a liquid crystal panel by laminating a first polarizing plate on the back side of a liquid crystal cell and laminating a second polarizing plate on the viewing side of the liquid crystal cell;
A first transporting step of the liquid crystal cell for transporting the liquid crystal cell so that the short side direction is the flow direction;
The back side of the liquid crystal cell supplied from the first roll-shaped polarizing plate in the first transporting step of the liquid crystal cell in the roll-shaped polarizing plate set according to claim 1 or 2. A first polarizing plate unwinding step of unwinding toward
A first polarizing plate cutting step of cutting the long polarizing plate after being unwound in the first polarizing plate unwinding step into a length corresponding to the short side of the liquid crystal cell;
Adhering a long polarizing plate unwound in the first polarizing plate unwinding step or a polarizing plate cut in the first polarizing plate cutting step to the liquid crystal cell conveyed in the first conveying step of the liquid crystal cell A first polarizing plate alignment step for adjusting to a position to be combined;
1st polarizing plate sticking which bonds the elongate polarizing plate after passing through the 1st polarizing plate alignment process, or the cut polarizing plate to the back side of the liquid crystal cell conveyed at the 1st conveyance process of the liquid crystal cell. A first polarizing plate unwinding step is performed first, and then the first polarizing plate cutting step, the first polarizing plate alignment step, and the first polarizing plate bonding step. Or the order of the first polarizing plate alignment step, the first polarizing plate cutting step, and the first polarizing plate bonding step, or the first polarizing plate alignment step, the first polarizing plate. 1st polarizing plate supply bonding process performed in order of the bonding process and the 1st polarizing plate cutting process;
The 2nd conveyance process of the liquid crystal cell which conveys the said liquid crystal cell so that the long side direction may turn into a flow direction; and the 2nd roll-shaped polarization | polarized-light among the sets of the roll-shaped polarizing plate of Claim 1 or 2. A second polarizing plate unwinding step of unwinding the long polarizing plate from the plate toward the viewing side of the liquid crystal cell conveyed in the second conveying step of the liquid crystal cell;
A second polarizing plate cutting step of cutting the long polarizing plate after being unwound in the second polarizing plate unwinding step into a length corresponding to the long side of the liquid crystal cell;
Adhering the long polarizing plate unwound in the second polarizing plate unwinding step or the polarizing plate cut in the second polarizing plate cutting step to the liquid crystal cell transported in the second transport step of the liquid crystal cell A second polarizing plate alignment step to match the position to be combined;
The second polarizing plate is pasted to the long polarizing plate after the second polarizing plate alignment step or the cut polarizing plate is bonded to the viewing side of the liquid crystal cell conveyed in the second conveying step of the liquid crystal cell. And the second polarizing plate unwinding step is first performed, and then the second polarizing plate cutting step, the second polarizing plate alignment step, and the second polarizing plate bonding step. Or the order of the second polarizing plate alignment step, the second polarizing plate cutting step, and the second polarizing plate bonding step, or the second polarizing plate alignment step, and the second polarizing plate. The manufacturing method of a liquid crystal panel including the 2nd polarizing plate supply bonding process performed in order of the bonding process and the said 2nd polarizing plate cutting process.   In the first polarizing plate unwinding step and the second polarizing plate unwinding step, the flow direction of the long polarizing plate unwound from the first roll-shaped polarizing plate in the first polarizing plate unwinding step, The manufacturing method of the liquid crystal panel of Claim 4 performed so that the flow direction of the elongate polarizing plate unwound from the 2nd roll-shaped polarizing plate at the said 2nd polarizing plate unwinding process may orthogonally cross.   6. The method of manufacturing a liquid crystal panel according to claim 4, wherein the liquid crystal cell is a VA mode liquid crystal cell.

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