TWI584005B - Method for storing polarizing plate, method for eleminating or decreasing wrinkle defect of polarizing plate, and method for producing polarizing plate - Google Patents

Description

Method for storing polarizing plate, method for eliminating or reducing wrinkle defects of polarizing plate, and method for manufacturing polarizing plate

The present invention relates to a method of storing a polarizing plate suitable for use in an image display device such as a liquid crystal display device, a method for eliminating or reducing wrinkle defects in a polarizing plate, and a method for producing a polarizing plate.

As a liquid crystal display device, a liquid crystal panel including a liquid crystal cell and a polarizing plate attached to the front and back surfaces thereof, and a casing accommodating the liquid crystal panel are widely used, and a liquid crystal panel is covered on the front side of the casing to cover the liquid crystal panel. And the frame edge of the peripheral portion of the front side polarizing plate. The frame edge has a requirement to further reduce the width from the viewpoint of design and the like.

On the other hand, the polarizing plate generally has a laminated structure in which a protective film is bonded to one surface or both surfaces of a polarizer via an adhesive layer (for example, JP-A-2004-245925). The polarizer and the protective film are usually made of different materials, and therefore, the polarizing plate may have wavy wrinkles (also referred to as wavy bending) during storage after manufacture. In this specification, weigh The appearance of the wavy deformation of such a polarizing plate is a "wrinkle defect".

Wrinkle defects, especially when the size of the polarizing plate is large, the height and/or number of wrinkles produced are more pronounced. When a wrinkle defect occurs on a polarizing plate, for example, when it is used in a liquid crystal display device, when a polarizing plate and a liquid crystal cell are bonded via an adhesive layer, the bonding interface between the adhesive layer and the liquid crystal cell is particularly Air bubbles are easily mixed in the peripheral portion of the bonding interface or in the vicinity thereof. When the bubble is generated in the image display area of the liquid crystal panel, a light spot may be formed at the time of lighting to reduce the sharpness. Therefore, the polarizing plate is required to be bonded to the liquid crystal cell, particularly in a liquid crystal display device using a casing having a narrow frame width as described above and a region in which a peripheral portion of the polarizing plate is used as an image display region. There is no wrinkle defect, or the wrinkle defect is sufficiently reduced to the extent that the above-mentioned bubble incorporation and the accompanying deterioration of the problem are not caused.

Therefore, an object of the present invention is to provide a method of storing a polarizing plate in a state in which a wrinkle-free defect is substantially maintained or a wrinkle defect can be suppressed so as not to cause a problem that the bubble is mixed and the clarity is reduced. . Further, another object of the present invention is to provide a method for substantially eliminating the wrinkle defects of a polarizing plate which has reached wrinkle defects, or suppressing wrinkle defects so as not to cause the above problems. Still another object of the present invention is to provide a method for producing a polarizing plate which is substantially free of wrinkle defects or which suppresses wrinkle defects so as not to cause the above problems.

The present invention provides a method of storing a polarizing plate shown below, a method for eliminating or reducing wrinkle defects of a polarizing plate, and a biasing method. The manufacturing method of the light board.

[1] A method of storing a polarizing plate, comprising: preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, wherein the polarizing plate is stored at 23 ° C and a relative humidity of 55%. At one week, a step of producing a polarizing plate having a height of more than 3 mm or a polarizing plate having three or more wrinkle defects on any side is generated on any side; and the moisture content of the polarizing plate after storage is changed The step of storing the polarizing plate in an environment where the moisture content of the polarizing plate at one week was stored in an environment of 23 ° C and a relative humidity of 55% was obtained.

[2] A method for eliminating or reducing wrinkle defects in a polarizing plate, comprising: preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, the polarizing plate being on either side a step of having a wrinkle having a height of more than 3 mm or a polarizing plate having three or more wrinkle defects on any side; and a moisture content of the polarizing plate after storage is lower than a moisture content of the polarizing plate before storage The step of storing the aforementioned polarizing plate in an environment.

[3] A method of producing a polarizing plate, comprising: preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, wherein the polarizing plate is stored at 23 ° C and a relative humidity of 55%. At one week, a step of producing a polarizing plate having a height of more than 3 mm or a polarizing plate having three or more wrinkle defects on any side is generated on any side; and the moisture content of the polarizing plate after storage is changed The step of storing the polarizing plate in an environment where the moisture content of the polarizing plate at one week was stored in an environment of 23 ° C and a relative humidity of 55% was obtained.

[4] A method of producing a polarizing plate, comprising: preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, the polarizing plate having a wrinkle defect having a height exceeding 3 mm on any side Or a step of having a polarizing plate having three or more wrinkle defects on any side; and a step of storing the polarizing plate in an environment in which the water content of the polarizing plate after storage is lower than the moisture content of the polarizing plate before storage .

[5] The method according to any one of [1] to [4] wherein the storing step includes the step of storing the polarizing plate in an environment of a relative humidity of 30 to 50%.

[6] The method according to any one of [1] to [5] wherein, in the storing step, the polarizing plate is stored in a sealed container.

[7] The method according to any one of [1] to [5] wherein, in the storing step, the polarizing plate is stored in a sealed container in which the dehumidifying agent is placed.

[8] The method according to any one of [1] to [7] wherein the polarizing plate prepared in the preparation step has a square shape having a long side of 700 mm or more and a short side of 400 mm or more.

The method according to any one of the above aspects, wherein at least one of the protective films is selected from the group consisting of a polyolefin resin film and a (meth)acrylic resin film. A thermoplastic resin film.

According to the present invention, it is possible to provide a degree of substantially no wrinkle defects when adhering to other members such as a liquid crystal cell, or to suppress wrinkle defects so as not to cause the above-mentioned bubble incorporation and the accompanying problem of reduced clarity. Polarized plate.

1‧‧‧Polar plate

10‧‧‧ polarizer

20‧‧‧1st protective film

30‧‧‧2nd protective film

40‧‧‧Adhesive layer

50‧‧‧Separation film

60‧‧‧ protective film

K‧‧‧End of polarizing plate

W‧‧‧Wave deformation

X‧‧‧ wave deformation

Y‧‧‧ wave deformation

Z‧‧‧ wave deformation

Fig. 1 is a side view showing an example of a polarizing plate having wrinkle defects.

2 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate which is provided in the storage method of the present invention, the method for eliminating or reducing wrinkle defects, and the method for producing a polarizing plate.

<Storage method of polarizing plate>

The method for storing a polarizing plate of the present invention comprises the steps of: (1) preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, the polarizing plate being at 23 ° C and a relative humidity of 55% In the case of storage for one week, a step of generating a wrinkle defect having a height of more than 3 mm or a polarizing plate A having three or more wrinkle defects on any side is generated on one side; and (2) The water content of the polarizing plate after the polarizing plate is lower than the step of storing the polarizing plate A in an environment in which the moisture content of the polarizing plate is stored for one week in an environment of 23 ° C and a relative humidity of 55%. Hereinafter, each step will be described.

(1) Polarizing plate A preparation step

The polarizing plate A which is provided in the storage method of the polarizing plate of the present invention is a polarizing plate which is liable to cause wrinkle defects which are caused by the above-mentioned bubble mixing and the problem of the sharpness reduction accompanying it under normal storage conditions, specifically Referring to Fig. 1, when stored at 23 ° C and 55% relative humidity for 1 week, a polarizing plate having a wrinkle defect of more than 3 mm or a wrinkle defect of 3 or more on any side is generated on either side. . Bias with such wrinkle defects The light board is very prone to the above problems. Fig. 1 is a side view showing an example of a polarizing plate having a wrinkle defect, which is a side showing a wrinkle defect in the polarizing plate. In the example of Fig. 1, the side has five wrinkle defects (wavy deformations W, X, and Z in Fig. 1), one of which is a wrinkle defect having a height of more than 3 mm (the wavy shape in Fig. 1) Deformation W).

The height of the wrinkle defect refers to the height from the plane to the top of the wrinkle defect when the polarizing plate is placed on the flat table. This height is measured in the side (edge portion) of the polarizing plate. Further, the number of wrinkle defects is substantially confirmed as the number of wrinkle defects, and specifically, the number of wrinkle defects from the height of the flat table when the polarizing plate is placed on the flat table is 0.5 mm or more. Therefore, the wavy deformation of the Y-based self-planar table having a height of less than 0.5 mm as shown in Fig. 1 is not counted as a wrinkle defect. When the height of the wavy deformation Z shown in Fig. 1 is 0.5 mm, it is calculated as a wrinkle defect. The number of wrinkle defects was also measured in the edge (edge portion) of the polarizing plate. Further, as shown in Fig. 1, K is the end (corner portion) of the edge (edge portion) of the polarizing plate, and is not calculated as a wrinkle defect even if it is floated from the flat table.

The shape of the polarizing plate A is not particularly limited, and a square (typically rectangular) polarizing plate layer having a long side of 700 mm or more and a short side of 400 mm or more is preferable. In a polarizing plate smaller than this size, wrinkle defects are generally difficult to be a problem. The polarizing plate A of the laminate can be obtained, for example, by cutting a polarizing plate manufactured into an elongated body. In the present specification, "preparation of the polarizing plate A" means that the polarizing plate A is obtained (manufactured).

The layer structure of the polarizing plate A is not particularly limited as long as it includes a polarizing plate and at least one protective film laminated on the polarizing plate. In the storage of the liquid crystal display device, for example, in the case of the storage of the liquid crystal display device, the polarizing plate has an adhesive layer for bonding to the liquid crystal cell. And, in general, a separate film for protecting the surface (outer surface) of the adhesive layer, and a protective film (surface protective film) for protecting the surface (outer surface) of the protective film, and thus the polarizing plate A, It is preferred to include not only a polarizer and a protective film but also an adhesive layer, a separation film, and a protective film.

An example of the layer configuration of the polarizing plate A is shown in the second aspect. The polarizing plate 1 shown in Fig. 2 includes a polarizing plate 10, a first protective film 20 bonded to one surface of the polarizing film 10, and a second protective film 30 bonded to the other surface of the polarizing film 10; The adhesive layer 40 on the outer surface of the second protective film 30; the separation film 50 laminated on the outer surface of the adhesive layer 40; and the protective film 60 laminated on the outer surface of the first protective film 20.

The polarizer 10 is provided with an optical film that absorbs linearly polarized light having a vibration plane parallel to the optical axis and penetrates linearly polarized light having a vibration plane perpendicular to the optical axis, and can be, for example, elongated in a uniaxial direction. A polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and aligned. As the dichroic dye, iodine and a dichroic organic dye can be used. The polyvinyl alcohol-based resin constituting the polarizer 10 may be, in addition to the polyvinyl alcohol of the polyvinyl acetate saponified product, vinyl acetate and other monomers copolymerizable with vinyl acetate (for example, ethylene and an unsaturated carboxylic acid). A vinyl alcohol-based copolymer of a saponified product of a copolymer of acid or the like. The thickness of the polarizer 10 is usually about 5 to 40 μm.

The polarizer 10 can be thinned by a polyvinyl alcohol resin a step of uniaxially stretching the film, a step of dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, and a step of treating the polyvinyl alcohol-based resin film having the dichroic dye adsorbed thereon with a boric acid aqueous solution And the step of treating with a boric acid aqueous solution and then washing with water. The dyeing of the dichroic dye can be carried out by immersing the film in an aqueous solution containing a dichroic dye, and the treatment with the aqueous boric acid solution can be carried out by immersing the film in an aqueous boric acid solution.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before dyeing, dyeing, or after dyeing of the dichroic dye. In the case where the uniaxial stretching is carried out after dyeing, the uniaxial stretching can be carried out before the boric acid treatment or in the boric acid treatment. Moreover, uniaxial stretching can also be performed among the plurality of stages.

The first and second protective films 20 and 30 may be a thermoplastic resin film having light transmissivity (preferably optically transparent). Specific examples of the thermoplastic resin include a polyolefin-based resin such as a chain polyolefin resin or a cyclic polyolefin resin (such as a decene resin); and a polyester resin such as polyethylene terephthalate; (meth)acrylic resin such as methyl methacrylate resin; cellulose resin such as cellulose triacetate or cellulose diacetate; polycarbonate resin; polyvinyl alcohol resin; Vinyl acetate resin; polyarylate resin; polystyrene resin; polyether-antimony resin; polyfluorene resin; polyamine resin; polyimine resin; and mixtures and copolymerizations thereof Things. In the present specification, the term "(meth)acrylic resin" means at least one selected from the group consisting of acrylic resins and methacrylic resins. Other terms with "(methyl)" are also with. At least one of the protective films contained in the polarizing plate A is preferably a thermoplastic resin film selected from the group consisting of a polyolefin resin film and a (meth)acrylic resin film.

The first protective film 20 and the second protective film 30 may be composed of a thermoplastic resin of the same type or may be composed of a different thermoplastic resin. The thickness of the first and second protective films 20 and 30 is, for example, about 5 to 200 μm, more preferably 10 to 150 μm, still more preferably 20 to 100 μm.

The adhesive layer 40 is for bonding a polarizing plate to a layer such as other members of the liquid crystal cell. Examples of the adhesive constituting the adhesive layer 40 include a (meth)acrylic adhesive, an urethane adhesive, a polyoxygen adhesive, a polyester adhesive, and a poly A guanamine-based adhesive, a polyether-based adhesive, a fluorine-based adhesive, a rubber-based adhesive, or the like. Among them, a (meth)acrylic adhesive is preferably used from the viewpoints of transparency, adhesion, reliability, reworkability and the like. The thickness of the adhesive layer 40 is usually 2 to 40 μm.

The separation film 50 and the protective film 60 are provided for the purpose of temporarily protecting the adhesive layer 40 and the first protective film 20 during storage, transportation, and inspection of the polarizing plate. The separation film 50 of the protective adhesive layer 40, which is the polarizing plate 1, is peeled off before being provided for practical use (for example, being attached to other members such as liquid crystal cells). Further, the protective film 60, usually after the polarizing plate 1 is provided for practical use (for example, attached to other members such as liquid crystal cells), is peeled off together with the adhesive layer.

The separation film 50 is usually composed of a thermoplastic resin film which has been subjected to release treatment on one side, and the release-treated surface is adhered to the adhesive film. Agent layer 40. Further, the protective film 60 is usually formed by providing an adhesive layer on one surface of a thermoplastic resin film. Examples of the thermoplastic resin constituting the separation film 50 and the pellicle film 60 may be, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, such as polyethylene terephthalate or polynaphthalene. A polyester resin such as ethylene formate. The description of the adhesive layer 40 will be described with respect to the adhesive layer of the protective film 60.

The layer configuration of the polarizing plate A is not limited to the example shown in Fig. 2, and may be, for example, the following layer configuration.

[a] omitting the configuration of any one or more of the adhesive layer 40, the separation film 50, and the protective film 60, [b] omitting the configuration of any of the first protective film 20 and the second protective film 30, and [c] use The optical compensation film of the retardation film is configured as the second protective film 30, and [d] includes an optical compensation film such as a retardation film in addition to the first protective film 20 and the second protective film 30.

One example of the above [b] is a configuration in which the second protective film 30 is omitted. A preferred embodiment is that the adhesive layer 40 is directly laminated on the surface of the polarizer 10 opposite to the protective film 60 to form the protective film 60. / First protective film 20 / polarizer 10 / adhesive layer 40 / separation film 50 layer structure.

A preferred specific example of the above [c] is a layer structure of the protective film 60 / the first protective film 20 / the polarizing plate 10 / the retardation film (second protective film 30) / the adhesive layer 40 / the separation film 50. Preferred one of the above [d] The embodiment is a layer of the protective film 60 / the first protective film 20 / the polarizer 10 / the second protective film 30 / the retardation film / the adhesive layer 40 / the separation film 50.

The retardation film is an optical film having optical anisotropy such as uniaxial or biaxial, and may be, for example, a film stretched with a thermoplastic resin. The thermoplastic resin may be a polytetrafluoroethylene/polymethyl methacrylate copolymer, a liquid crystal polyester, or a B, in addition to the above-mentioned first and second protective films 20 and 30. Sulfhydryl cellulose, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride, and the like. The extension ratio is usually about 1.01 to 6 times.

When the polarizer 10 and the first protective film 20 and the second protective film 30 (including the case of a retardation film), an adhesive or an adhesive (refer to the above description for the adhesive layer 40 for the adhesive) can be used. Hehe. As the subsequent agent, a water-based adhesive, that is, a person who dissolves the adhesive component in water or is dispersed in water, and an active energy ray-curable adhesive can be used.

The adhesive component of the water-based adhesive may, for example, be a polyvinyl alcohol-based resin or a urethane resin. The active energy ray-curable adhesive may, for example, be an active energy ray-curable compound such as an epoxy compound or a (meth)acrylic compound, or a curable composition containing a polymerization initiator. The active energy ray-curable adhesive may be a solventless adhesive or an organic solvent (a solvent other than water). When a solventless type of adhesive is used, there is no need for a drying treatment for removing the solvent. When an active energy ray-curable adhesive is used, the film is laminated via an adhesive, and then irradiated with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, preferably purple. The outer layer is irradiated to harden the adhesive layer.

When a water-based adhesive is used, the film laminate which is bonded via the adhesive is usually subjected to a drying treatment to remove moisture of the adhesive layer. In this case, when the film bonded to the polarizer 10 is a low moisture permeable thermoplastic resin film, the drying time is prolonged, the productivity is lowered, or the water in the water-based adhesive cannot be sufficiently dried, and the force is further increased. Reduced situation. In this regard, the active energy ray-curable adhesive is more advantageous in that the above problem is not caused when the low moisture permeable thermoplastic resin film is bonded.

When the low moisture permeable thermoplastic resin film is bonded to the polarizer 10, the difference in moisture content from the polarizer 10 becomes large, and the wrinkle defect of the polarizing plate tends to be large. Therefore, the present invention is particularly effective when a low moisture permeability thermoplastic resin film is used as the first protective film 20 and/or the second protective film 30 (including a case of a retardation film). Specific examples of the low moisture permeable thermoplastic resin film include a polyolefin resin such as a chain polyolefin resin or a cyclic polyolefin resin (northrene resin); for example, a methyl methacrylate system Resin (meth)acrylic resin.

(2) Polarizer A storage step

In the present embodiment, the polarizing plate A is stored in an environment in which the moisture content S1 of the polarizing plate after storage is lower than the moisture content S0 of the polarizing plate stored for one week in an environment of 23° C. and a relative humidity of 55%. Further, the storage referred to therein also includes the case where the polarizing plate A or the like is carried.

The polarizing plate A described above has a wrinkle defect having a height of more than 3 mm or a polarized light having three or more wrinkle defects on an arbitrary side on any side under conditions of 23° C., a relative humidity of 55%, and storage for one week. According to the storage method of the present step, the plate can be kept in a state in which the wrinkle-free defect is substantially maintained, or the wrinkle defect can be suppressed, and the polarizing plate can be stored to the extent that the bubble is not mixed and the clarity is reduced. In other words, the polarizing plate can be stored in a state in which no wrinkle defect of more than 3 mm is generated on any side, and three or more wrinkle defects are not generated on any side.

The water content of the polarizing plate was determined by the following drying test. That is, a sample of 200 mm × 300 mm was cut out from the polarizing plate to be measured, and the sample was dried in an oven set at 105 ° C for 2 hours to carry out a drying test. When the weight of the sample before the drying test is taken as W0, and the weight of the sample after the drying test is taken as W1, the moisture content (%) of the polarizing plate can be defined by the following formula: Polarizer moisture content (%) = 100 × {(W0-W1) / W0}

The moisture content S1 of the polarizing plate of the polarizing plate A after storage is 0.9 times the moisture content S0 of the polarizing plate when stored at 23 ° C and a relative humidity of 55% from the viewpoint of effectively suppressing the wrinkle defect. The following (S1 ≦ 0.9S0) is preferable, and 0.85 times or less (S1 ≦ 0.85 S0) is more preferable. Further, in general, the moisture content S1 of the polarizing plate is 0.5 times or more (S1 ≧ 0.5 S0) of the water content S0 of the polarizing plate.

A specific method for storing the polarizing plate A in a low-humidity environment in which the moisture content of the polarizing plate is lower than 23 ° C and the relative humidity is 55% in an environment where the moisture content of the polarizing plate is kept for one week. The method of storage under conditions is preferred. The method of storing under low humidity conditions may be, for example, a method of sealing a polarizing plate A by using a sealable film package having water repellency (moisture resistance) and gas barrier properties as a sealed container; use A sealable plastic container, a metal container, or the like as a sealed container, a method of sealing the polarizing plate A, and the like.

Further, in view of effectively suppressing wrinkle defects, the step of storing the polarizing plate A in an environment containing 30 to 50% relative humidity is preferred to include internal relative humidity of 30 to 50%. The step of storing the polarizing plate A in the sealed container is more preferable, and the step of storing the polarizing plate A in the sealed container having the internal relative humidity of 35 to 45% as described above is more preferable. When it is stored in an environment where the relative humidity is less than 30%, the wrinkle defect height tends to increase. Further, when stored in an environment where the relative humidity exceeds 50%, the number of wrinkle defects tends to increase.

A suitable method for making the relative humidity in the sealed container within the above range (reducing the relative humidity in the sealed container) is to introduce a low-humidity inert gas (nitrogen, air, etc.) and a desiccant such as a desiccant into a sealed container. In the case of using an inert gas, an inert gas is introduced into the sealed container, and the polarizing plate A is sealed in a state of being replaced by the gas. In the case of using a desiccant, a desiccant is placed in a sealed container, and the package is sealed at the same time as the polarizing plate A.

For low-humidity air, dry air can be used. For example, instrument air compressed by an air compressor (relative humidity, usually about 40% or less) can be used. As the desiccant, various porous bodies such as silicone (silicone type A, silicone type B, etc.), molecular sieves, activated carbon, and the like can be used.

The present invention also relates to a method of producing a polarizing plate comprising the step of storing the polarizing plate A in the above environment. The manufacturing method of the polarizing plate comprises the following steps: (1') A polarizing plate comprising at least one protective film comprising a polarizer and a layer deposited on the polarizer is prepared, and the polarizing plate is produced on any side when stored at 23 ° C and a relative humidity of 55% for one week. a step of forming a polarizing plate A having a height of more than 3 mm, or a polarizing plate A having three or more wrinkle defects on any side; and (2') making the moisture content of the polarizing plate after storage lower than 23 ° C, relative The step of storing the polarizing plate A in an environment where the moisture content of the polarizing plate at one week is stored in an environment of 55% humidity.

For the details of steps (1') and (2'), the above description of steps (1) and (2) is cited. According to the method for producing a polarizing plate, it is possible to provide a polarizing plate which is substantially free of wrinkle defects or which suppresses wrinkle defects so as not to cause the above-mentioned bubble incorporation and the problem of reduced clarity.

<Method for eliminating or reducing wrinkle defects>

The method for eliminating or reducing the wrinkle defect of the present invention comprises the steps of: (I) preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, and the polarizing plate is on any side a step of having a wrinkle defect having a height of more than 3 mm or a polarizing plate B having three or more wrinkle defects on any side; and (II) a polarizing plate having a moisture content after storage of the polarizing plate lower than that before storage The step of storing the polarizing plate B in an environment of moisture content.

The polarizing plate B which is provided to the method for eliminating or reducing the wrinkle defect of the present invention is a polarizing plate which generates wrinkle defects accompanying the problem of bubble mixing as described above and the accompanying problem of reduced clarity, specifically, A polarizing plate having a wrinkle defect having a height exceeding 3 mm on any side or having three or more wrinkle defects on any side. The meaning and measurement method of the height and number of wrinkle defects are the same as described above.

The shape of the polarizing plate B is not particularly limited, and a square (typically rectangular) polarizing plate layer having a long side of 700 mm or more and a short side of 400 mm or more is preferable. In a polarizing plate smaller than this size, wrinkle defects are generally difficult to be a problem. The polarizing plate B of the laminate may be, for example, a polarizing plate in which a polarizing plate manufactured as an elongated body is cut, and wrinkles are generated during storage and transportation under arbitrary conditions. Regarding the layer constitution of the polarizing plate B, the description about the polarizing plate A is cited. In the present specification, "preparation of the polarizing plate B" means that the polarizing plate B is obtained (made).

According to the above step (II), by storing the polarizing plate B in an environment in which the moisture content T1 of the polarizing plate after storage is lower than the moisture content T0 of the polarizing plate before storage, the wrinkle defect of the polarizing plate B can be substantially eliminated. Or, the wrinkle defect can be suppressed to the extent that the bubble intrusion and the accompanying deterioration of the problem are not caused. That is, a polarizing plate which does not have a wrinkle defect having a height exceeding 3 mm on any side and which does not have three or more wrinkle defects on any side can be obtained. At the same time, the storage referred to therein also includes the case of carrying the polarizing plate B and the like. The method of determining the moisture content of the polarizing plate is as described above.

The moisture content T1 of the polarizing plate of the polarizing plate B after storage is preferably 0.9 times or less (T1 ≦ 0.9T0) of the moisture content T0 of the polarizing plate before storage, from the viewpoint of effectively eliminating or reducing the wrinkle defect. 0.85 times or less (T1 ≦ 0.85T0) is more preferable. Further, in general, the moisture content of the polarizing plate T1 is 0.5 times or more (T1 ≧ 0.5 T0) of the moisture content T0 of the polarizing plate.

The specific method for storing the moisture content T1 of the polarizing plate after storage is lower than the moisture content T0 of the polarizing plate before storage, and the above-described method for making the moisture content S1 of the polarizing plate lower than 23 The specific method of storing the polarizing plate A in the environment where the moisture content of the polarizing plate S0 is stored for one week in an environment of ° C and a relative humidity of 55% is the same.

From the viewpoint of effectively eliminating or reducing wrinkle defects, the step of storing the polarizing plate B in the environment of the relative humidity of 30 to 50% in the above step (II) is preferable to include the internal relative humidity of 30 to 50. The step of storing the polarizing plate B in the % sealed container is more preferable, and the step of storing the polarizing plate B in the sealed container having the internal relative humidity of 35 to 45% is more preferable. When it is stored in an environment where the relative humidity is less than 30%, the wrinkle defect height tends to increase. Further, when stored in an environment where the relative humidity exceeds 50%, the number of wrinkle defects tends to increase. The description of the method for storing the polarizing plate A is made for a specific method of making the relative humidity in the sealed container within the above range (reducing the relative humidity in the sealed container).

The present invention relates to a method of producing a polarizing plate including the step of storing the polarizing plate B in the above environment. The method for producing the polarizing plate includes the steps of: (I') preparing a polarizing plate including a polarizing plate and at least one protective film laminated on the polarizing plate, and the polarizing plate has a height exceeding 3 mm on any side. a step of wrinkle defects or a polarizing plate B having three or more wrinkle defects on any side; and (II') a moisture content of the polarizing plate after storage is lower than a moisture content of the polarizing plate before storage The step of storing the polarizing plate B in the environment.

For the details of steps (I') and (II'), the foregoing descriptions of steps (I) and (II) are cited. According to the method for producing a polarizing plate, it is possible to provide a polarizing plate which is substantially free of wrinkle defects or which suppresses wrinkle defects so as not to cause the above-mentioned bubble incorporation and the problem of reduced clarity.

(Example)

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

<Experiment 1>

[1] Production of polarizing plate

An elongated body polarizing plate having the configuration shown in Fig. 2 was prepared. The layer structure of the polarizing plate is a protective film 60 (composed of a (meth)acrylic adhesive layer and a polyethylene terephthalate film) having a thickness of 75 μm/the first protective film 20 having a thickness of 80 μm ((A) (Acrylic resin film) / Polarizing sheet 10 having a thickness of 23 μm (Polyvinyl alcohol film adsorbed and iodine-adsorbed) / Second protective film 30 having a thickness of 50 μm (Retardation film composed of a cyclic polyolefin resin) / Thickness A 25 μm adhesive layer 40 ((meth)acrylic adhesive layer)/38 μm thick separation film 50 (polyethylene terephthalate film). The long-length polarizing plate was cut into a rectangle of 1220 mm × 690 mm to prepare a polarizing plate A of a laminate.

[2] Storage of polarizing plate A

The storage step of the polarizing plate A of the laminate obtained above was carried out under the following four conditions of Reference Example 1, Comparative Example 1, and Examples 1 to 2. The following four storage steps are carried out immediately after the polarizing plate A of the laminate is cut.

(Reference example 1)

200 sheets of polarizing plate A were placed in a container and stored in an environment of 23 ° C and a relative humidity of 55% for 7 days.

(Comparative Example 1)

200 sheets of polarizing plate A were placed in a plastic container having a rubber groove in the opening portion and sealed, and sealed, and stored in an environment of 23 ° C for 10 days. The relative humidity at the beginning of storage was 55%, and the relative humidity after storage for 10 days was 53%. For the measurement of the temperature and humidity in the container, "Ondotori" (Tr-72Ui manufactured by T & D Corporation) was used (the same applies hereinafter).

(Example 1)

In the same plastic container as the user of Comparative Example 1, 200 polarizing plates A were placed, and 10 g of a silicone type A (CP series manufactured by Fuji GEL Industries Co., Ltd.) was placed and sealed, and sealed at 23 Store in the environment of °C for 10 days. The relative humidity at the beginning of storage was 55%, and the relative humidity after storage for 10 days was 42%.

(Example 2)

After 200 polarizing plates A were placed in the same plastic container as the user in Comparative Example 1, the container air was introduced and filled in a container at 23 ° C and a relative humidity of 30%, and sealed, and the environment was sealed at 23 ° C. Keep it for 10 days. The relative humidity at the beginning of storage was 45%, and the relative humidity after storage for 10 days was 47%.

[3] Evaluation of polarizing plates after storage

For the following items, the evaluation of the polarizing plate after the storage step is performed. The results are shown in Table 1.

(Polarizer moisture content)

One piece of the polarizing plate 200 after the storage step was randomly taken out, and the above-mentioned drying test was performed on the polarizing plate, and the moisture content of the polarizing plate was calculated according to the above definition. Further, the moisture content of the polarizing plate of the polarizing plate A before storage (immediately after cutting) was 1.8%.

(number and height of wrinkle defects)

One piece of the polarizing plate 200 after the storage step is randomly taken out, and the polarizing plate is placed down on the plane of the protective film 60 to measure the number of wrinkle defects on each side of the polarizing plate (as described above, limited to the self-plane) The height of the table is 0.5 mm or more of the wrinkle defect), and the height of the wrinkle defect from the plane table. In Table 1, the number of wrinkle defects including the side of the most wrinkle defect and the height of the highest wrinkle defect among all the wrinkle defects are described.

(The presence or absence of bubbles)

One piece of the polarizing plate 200 after the storage step was randomly taken out, and the polarizing plate was attached to the alkali-free glass through a large-scale precision laminating machine (manufactured by Climb Products, HAL-1485) through an adhesive layer of a polarizing plate. (Manufactured by Corning, EAGLE XG), it was visually confirmed whether or not bubbles were present in the peripheral portion of the bonding interface between the adhesive layer and the alkali-free glass.

<Experiment 2>

[1] Storage of polarizing plate A

The storage step of the polarizing plate A of the laminate produced in Experiment 1 was carried out under the following four conditions of Comparative Example 2 and Examples 3 to 5. The following four storage steps are carried out immediately after the polarizing plate A of the laminate is cut.

(Comparative Example 2)

As a film package having water repellency and gas barrier properties, a sterilizing bag in which a film of aluminum is used as a moisture-proof layer and a plurality of layers of gas barrier resin film are laminated (Poto Chemical Industry Co., Ltd.) 30 sheets of polarizing plate A were placed, sealed, and stored in an environment of 23 ° C for 10 days. The relative humidity at the beginning of storage was 55%, and the relative humidity after storage for 10 days was 50%.

(Example 3)

After placing 30 polarizing plates in the same sterilization bag as the user of Comparative Example 2, the container air was introduced and filled in a container at 23° C. and a relative humidity of 30%, and sealed, and stored in an environment of 23° C. 10th. The relative humidity at the beginning of storage was 36%, and the relative humidity after storage for 10 days was 39%.

(Example 4)

After placing 30 polarizing plates in the same sterilization bag as the user of Comparative Example 2, the container was introduced and filled with nitrogen gas at 23 ° C, sealed, and stored in an environment of 23 ° C for 10 days. The relative humidity at the beginning of storage was 35%, and the relative humidity after storage for 10 days was 36%.

(Example 5)

In the same sterilization bag as the user of Comparative Example 2, 30 polarizing plates A were placed, and 10 g of a silicone type A (product of the CP series manufactured by Fuji GEL Industries Co., Ltd.) was placed and sealed, and sealed at 23 Store in the environment of °C for 10 days. The relative humidity at the beginning of storage was 55%, and the relative humidity after storage for 10 days was 35%.

[2] Evaluation of polarizing plates after storage

In the same manner as in Experiment 1, the polarizing plate after the storage step was evaluated for the moisture content of the polarizing plate, the number and height of wrinkle defects, and the presence or absence of bubbles. The results are shown in Table 2. Furthermore, in Table 2, for comparison, The storage conditions and evaluation results of Reference Example 1 are also displayed.

<Experiment 3>

[1] Storage of polarizing plate B (elimination or reduction of wrinkle defects)

With respect to the polarizing plate (polarizing plate B) after the storage step obtained in Reference Example 1, the storage step was carried out under the following two conditions of Examples 6 to 7, and the wrinkle defects were eliminated or reduced.

(Example 6)

200 in the same plastic container as the user in Comparative Example 1 After the polarizing plate B, the instrument air was introduced and filled in a container at 23 ° C and a relative humidity of 30%, sealed, and stored in an environment of 23 ° C for 5 days. The relative humidity at the beginning of the storage was 44% (relative humidity, adjusted according to the introduction time of the instrument air), and the relative humidity after storage for 5 days was 45%.

(Example 7)

After 200 polarizing plates B were placed in the same plastic container as those of the user in Comparative Example 1, the container air was introduced and filled in a container at 23 ° C and a relative humidity of 30%, and sealed in an environment of 23 ° C. Keep it for 5 days. The relative humidity at the beginning of the storage was 38% (relative humidity, adjusted according to the introduction time of the instrument air), and the relative humidity after storage for 5 days was 40%.

[2] Evaluation of polarizing plates after storage

With respect to the polarizing plate after the storage step, the moisture content of the polarizing plate, the number and height of the wrinkle defects, and the presence or absence of bubbles were evaluated in the same manner as in Experiment 1. The results are shown in Table 3. In addition, in Table 3, the storage conditions and the evaluation result of Reference Example 1 are also shown together for comparison.

1‧‧‧Polar plate

10‧‧‧ polarizer

20‧‧‧1st protective film

30‧‧‧2nd protective film

40‧‧‧Adhesive layer

50‧‧‧Separation film

60‧‧‧ protective film

Claims (10)

A method for storing a polarizing plate, comprising: a step of preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, wherein the polarizing plate has a square having a long side of 700 mm or more and a short side of 400 mm or more The shape is a laminate, and when the polarizer is stored in an environment of 23° C. and a relative humidity of 55% for one week, wrinkles having a height of more than 3 mm are generated on either side, or may be generated on any side. a polarizing plate having three or more wrinkle defects; and an environment in which the moisture content of the polarizing plate after storage is kept lower than the moisture content of the polarizing plate stored in an environment of 23° C. and a relative humidity of 55% for one week. In the storage step of the polarizing plate, the moisture content (S1) of the polarizing plate after storage is 0.5 times or more and 0.9 times the moisture content (S0) of the polarizing plate stored for one week in an environment of 23° C. and a relative humidity of 55%. the following. A method for reducing wrinkle defects in a polarizing plate, comprising: a step of preparing a polarizing plate comprising a polarizing plate and at least one protective film laminated on the polarizing plate, wherein the polarizing plate has a long side of 700 mm or more, a square shape having a short side of 400 mm or more and a laminate body, and the polarizing plate is a polarizing plate having a wrinkle defect having a height exceeding 3 mm on any side or having three or more wrinkle defects on an arbitrary side; The storage step of storing the polarizing plate in an environment in which the moisture content of the polarizing plate after storage is lower than the moisture content of the polarizing plate before storage. In addition, the moisture content (T1) of the polarizing plate after storage is 0.5 times or more and 0.9 times or less of the moisture content (T0) of the polarizing plate before storage. The method of storing a polarizing plate according to the first aspect of the invention, wherein the storing step includes the step of storing the polarizing plate in an environment of a relative humidity of 30 to 50%. The method for eliminating wrinkle defects in the polarizing plate according to the second aspect of the invention, wherein the storing step includes the step of storing the polarizing plate in an environment of a relative humidity of 30 to 50%. The method of storing a polarizing plate according to claim 1, wherein in the storing step, the polarizing plate is stored in the sealed container. The method for eliminating wrinkle defects in the polarizing plate according to the second aspect of the invention, wherein in the storing step, the polarizing plate is stored in the sealed container. The method of storing a polarizing plate according to the first aspect of the invention, wherein in the storing step, the polarizing plate is stored in a sealed container in which the dehumidifying agent is placed. The method for eliminating wrinkle defects in the polarizing plate according to the second aspect of the invention, wherein in the storing step, the polarizing plate is stored in a sealed container in which the dehumidifying agent is placed. The method of storing a polarizing plate according to the first aspect of the invention, wherein at least one of the protective films is a thermoplastic resin selected from the group consisting of a polyolefin resin film and a (meth)acrylic resin film. film. The pleats of the polarizing plate described in item 2 of the patent application scope In the protective film, at least one of the protective films is a thermoplastic resin film selected from the group consisting of a polyolefin resin film and a (meth)acrylic resin film.