TW201629539A - Manufacturing method of polarizing sheet plate - Google Patents

Abstract

The invention provides a manufacturing method of polarizing sheet plate has: a step that prepares a first polarizing sheet plate, being a rectangle shape with long sides and short sides, having a polarizer and a protect film laminated on at least one surface of the polarizer has one or more wave-shape defects on at least any one of the long sides; a step that reduces moisture percentage of 0.05 mass% or more and obtains second polarizing sheet plate.

Description

Method for manufacturing polarizing plate sheet

The present invention relates to a method of manufacturing a polarizing plate sheet suitable for use in an image display device such as a liquid crystal display device and capable of reducing waveform defects.

A polarizing plate used in an image display device such as a liquid crystal display device 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, and a long polarizing plate and a strip are used. In the form of a roll of the protective film, a long strip (polarizer roll) is produced by a roll-to-roll method [for example, JP-A-2009-134190 (Patent Document 1)]. The obtained long strip-shaped polarizing plate is cut into a sheet-like body of a predetermined size in accordance with the screen size of the image display device, and is adhered to an image display element such as a liquid crystal cell by an adhesive layer or the like, and laminated. And combined in the image display device.

Patent Document 1 describes a method for suppressing the problem of so-called reverse curl and waveform curl generated in a polarizing plate by laminating a long polarizing film and a long protective film via an adhesive. Obtaining a laminated body, and then forming an arc along the longitudinal direction of the laminated body On the convex curved surface, the laminate is adhered to one another, and the adhesive is polymerized and cured.

[Previous Technical Literature] (Patent Literature)

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2009-134190

According to the method described in Patent Document 1, the occurrence of the above problem can be suppressed immediately after the production of at least a long polarizing plate or immediately after cutting into a sheet-like body. However, the polarizing plate (polarizing plate sheet) which has been cut into a sheet-like body does not have the above-mentioned problem at the initial stage, but a waveform defect may occur during storage due to moisture absorption through the storage environment. The "waveform defect" refers to a deformation defect which is undulated in at least one side of the sheet of the polarizing plate and the end portion including the polarizing plate. When a wave defect is generated in the polarizing plate sheet, for example, when the liquid crystal display device is used as an example, when the polarizing plate sheet is bonded to the liquid crystal cell via the adhesive layer, the adhesive layer and the liquid crystal cell are bonded. The bonding interface is particularly easy to mix air bubbles in the end region of the bonding interface and its vicinity. When this bubble is generated in the image display area of the liquid crystal panel, it becomes a bright spot at the time of lighting, and the visibility of the liquid crystal display device is lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a polarizing plate sheet having a reduced number or height of waveform defects.

The present invention provides a method of producing a polarizing plate sheet body shown below.

[1] A method for producing a polarizing plate sheet, comprising the steps of: preparing a first polarizing plate-like body, wherein the first polarizing plate-like system includes a polarizing plate and at least one side of the polarizing plate; a laminated protective film having a square shape of a long side and a short side, and having one or more waveform defects in at least one of the long sides; and the first polarizing plate-like body The step of reducing the water content by 0.05% by weight or more to obtain the second polarizing plate sheet.

[2] The production method according to the above [1], wherein the first polarizing plate-like body includes an adhesive layer, and in the step of obtaining the second polarizing plate-like body, the first polarizing plate-like body is used The moisture content is reduced by less than 0.2% by weight.

[3] The production method according to the above [1], wherein, in the step of preparing the first polarizing plate sheet, the waveform defects included in at least one of the long sides are three or more.

[4] The production method according to the above [1], wherein, in the step of preparing the first polarizing plate sheet, the height of the waveform defect included in at least one of the long sides exceeds 2 mm.

The production method according to any one of the above aspects, wherein the first polarizing plate-like system includes the polarizer, and a layer of the first adhesive layer is laminated on one surface thereof. The first protective film and the second protective film laminated on the other surface via the second adhesive layer.

[6] The production method according to the above [5], wherein the first protective film and the second protective film have a moisture permeability of 30 g/(m ² ‧24 hr) or more at a temperature of 40 ° C and a relative humidity of 90%.

The production method according to the above [5], wherein at least one of the first adhesive layer and the second adhesive layer is composed of a cured product of an active energy ray-curable adhesive. .

[8] The production method according to any one of [1] to [7], wherein the moisture content is reduced by sealing the first polarizing plate sheet and the humidity control agent together in the moisture-proof container.

According to the present invention, it is possible to provide a polarizing plate sheet having a reduced number or height of waveform defects. In particular, the present invention can provide a method for producing a polarizing plate sheet-like body, and can reduce waveform defects to a polarizing plate-like sheet having three or more waveform defects having a wave defect of more than 2 mm. limit.

1‧‧‧1st polarizing plate sheet

10‧‧‧ polarizer

20‧‧‧1st protective film

30‧‧‧2nd protective film

40‧‧‧Adhesive layer

50‧‧‧Separation film

60‧‧‧Protective film

Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of a first polarizing plate sheet.

The method for producing a polarizing plate sheet of the present invention comprises the steps of: (1) preparing a first polarizing plate sheet, wherein the first polarizing plate system includes a polarizing film and at least the polarizing film a protective film laminated on one side, and is a polarizing plate-like body having a square shape of long sides and short sides, And a step of obtaining a second polarizing plate sheet by having one or more waveform defects in at least one of the long sides and (2) reducing the moisture content of the first polarizing plate sheet by 0.05% by weight or more .

Hereinafter, each step will be described.

(1) Step of preparing the first polarizing plate sheet

In the case where the first polarizing plate-like system is subjected to the operation of the waveform defect, the polarizing plate-like body which is likely to be mixed with the above-described bubble and the problem of the decrease in visibility therewith is specifically at least one. A polarizing plate sheet having one or more waveform defects in the long side. As a result of further generating a waveform defect in the first polarizing plate sheet, it is possible to have a waveform defect having a height exceeding 2 mm in at least one long side or three or more waveform defects in at least one long side. In the polarizing plate sheet-like body, the first polarizing plate sheet body has three or more waveform defects in at least one long side, and any one or more of the waveform defects is a waveform defect having a height exceeding 2 mm. .

The height of the waveform defect refers to the height from the plane table to the top of the waveform defect when the first polarizing plate sheet is placed on the plane table. At this time, the first polarizing plate sheet is attached to the image display element. The side of the side (for example, the liquid crystal cell) is placed face up on the flat table. The height of the waveform defect was measured at the side (end portion) of the first polarizing plate sheet. In addition, the number of waveform defects is substantially the number of waveform defects. Specifically, when the first polarizing plate-like body is placed on a flat table, the height is 0.5 mm or more from the plane. The number of waveform defects. The number of waveform defects is also in the first 1 Measured in the side (end) of the sheet of the polarizing plate.

The first polarizing plate sheet is a square shape having a long side and a short side, and is a typical rectangular shape. The length of the long side and the short side is not particularly limited, but usually, the long side of the first polarizing plate-like body is 700 mm or more, and the short side is 400 mm or more. The waveform defect is the larger the size of the first polarizing plate sheet, and the height of the waveform and the number of generated waveforms are likely to be remarkable. When the size (long side and/or short side) is too small, the problem of waveform defects itself is not easy to occur. The first polarizing plate sheet-like body is a polarizing plate in which a polarizing plate for producing a long strip is cut, and then stored and transported under any conditions, and a polarizing plate having a waveform defect as described above can be produced.

In general, the first polarizing plate-like body having a waveform defect having a height of more than 2 mm or three or more waveform defects on the long side of any one of the long sides has the same degree of waveform defects on the long side opposite to the long side. . Further, the first polarizing plate-like body having a waveform defect having a height exceeding 2 mm or three or more waveform defects on any one of the long sides is often a waveform defect in the two short sides. However, the waveform defects generated on the two short sides have a smaller tendency in the height and/or the number of waveform defects generated on the long side, and the waveform defects in the short side, Compared with the waveform defects on the long side, there is a tendency that bubbles do not easily enter. Therefore, in order to suppress the problem of air bubble incorporation and the decrease in visibility therewith, it is necessary to particularly reduce the waveform defects generated on the long side.

The layer structure of the first polarizing plate-like sheet is not particularly limited as long as it includes a protective film which is laminated on at least one surface of the polarizing plate, and the protective film can be bonded to the two-layer layer of the polarizing plate. Protective film usually The laminate is laminated on the polarizer via an adhesive layer.

The first polarizing plate sheet may have a layer (or film) other than the polarizing plate and the protective film. For example, in general, a polarizing plate for manufacturing a long strip and a polarizing plate sheet system for cutting the same are used to adhere to an adhesive layer of an image display element (for example, a liquid crystal cell), and are formed to be laminated on the polarizing plate in advance. A polarizing plate having an adhesive layer on its surface, although many are also circulated on the market, may include a first polarizing plate sheet or such an adhesive layer. When the adhesive layer is contained, a separation film (separation sheet) for protecting the surface (outer surface) is usually laminated on the outer surface of the adhesive layer.

Further, a polarizing plate for producing a long article is usually stored as a polarizing plate roll and stored or circulated. However, in order to protect the outer protective film surface during winding, a protective film is generally provided with protection. A film (surface protection film). In this case, the polarizing plate is cut into a polarizing plate sheet and generally has a protective film. In this case, the first polarizing plate sheet may include a protective film laminated on the protective film.

Further, the protective film of the first polarizing plate sheet may have a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and the like on the outer surface (the surface opposite to the polarizer). The surface treatment layer (coating layer) of the stain layer. Further, the first polarizing plate sheet may include a layer or film having an optical function other than the polarizing plate. One example of this is a retardation film.

An example of the layer configuration of the first polarizing plate sheet is shown in Fig. 1. The first polarizing plate sheet 1 shown in Fig. 1 includes a polarizing plate 10, a first protective film 20 bonded to one surface of the polarizing film 10, and a second protective layer bonded to the other surface of the polarizing film 10. Film 30; laminated in the second The adhesive layer 40 on the outer surface of the 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. In addition to the polarizer 10 and the protective film (the first protective film 20 and the second protective film 30), the layer structure of the adhesive layer 40, the separation film 50, and the protective film 60 is ideal for the first polarizing plate sheet. One of the layers.

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

The polarizer 10 can be produced by a method comprising the following steps. These steps are a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, adsorbing the dichroic dye, and adsorbing a dichroic dye. The polyvinyl alcohol-based resin film is treated with a boric acid aqueous solution, and the step of washing 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 of the aqueous boric acid solution can be carried out by immersing the film in an aqueous boric acid solution.

Uniaxial extension of a polyvinyl alcohol resin film, which can be used in two The dyeing of the coloring pigment is carried out simultaneously with the dyeing or after the dyeing. When the uniaxial extension is carried out after dyeing, this uniaxial stretching can be carried out before the boric acid treatment or in the boric acid treatment. Also, uniaxial stretching can be performed in these plural stages.

The first and second protective films 20 and 30 may be a translucent (ideally optically transparent) thermoplastic resin film. Specific examples of the thermoplastic resin include a polyolefin resin such as a chain polyolefin resin (such as a polypropylene resin) or a cyclic polyolefin resin (such as a decene resin); and a polyester resin (poly pair) Ethylene phthalate resin, etc.; (meth)acrylic resin (methyl methacrylate resin, etc.); cellulose resin (such as triethylene fluorene cellulose [TAC], diethyl phthalocyanine) Cellulose acetate resin; polycarbonate resin; polyvinyl alcohol resin; polyvinyl acetate resin; polyarylate resin; polystyrene resin; polyether oxime resin; polyfluorene resin; Polyamide resin; polyamido resin; and mixtures and copolymers thereof. The thickness of the first and second protective films 20 and 30 is, for example, about 5 to 200 μm, preferably 10 to 150 μm, and more preferably 15 to 100 μm. In the present specification, "(meth)acrylic acid" means at least one selected from the group consisting of acrylic acid and methacrylic acid.

The first polarizing plate sheet 1 shown in FIG. 1 includes the first protective film 20 on one surface of the polarizer 10 and the first protective film 20 on the other surface. 2 The protective film 30 may be composed of the same type of thermoplastic resin or may be composed of different types of thermoplastic resins. However, when the moisture permeability of the protective film bonded to both surfaces is different when the thermoplastic resin is composed of different types of thermoplastic resins, Waveform defects are particularly prone to occur due to differences in hygroscopicity, so the present invention is particularly advantageous as the case may be. According to the present invention, even if the moisture permeability difference of the protective film laminated on both sides is 30 g/(m ² ‧24 hr) or more, further 50 g/(m ² ‧24 hr) or more, even 100 g/(m ² ‧24 hr) In the above, in particular, when it is 300 g/(m ² ‧24 hr) or more, a polarizing plate sheet having a problem that the waveform defects are reduced and the bubble is less likely to be mixed and the visibility is lowered can be obtained. Usually, the difference in moisture permeability of the protective film bonded to both sides is 900 g/(m ² ‧24 hr) or less.

The moisture permeability is measured at a temperature of 40 ° C and a relative humidity of 90% by a cup method in accordance with JIS Z 0208. The combination of the protective film having a temperature difference of 40° C. and a relative humidity of 90% and having a moisture permeability difference of 30 g/(m ² ‧24 hr) or more may, for example, be a cellulose resin film (such as a TAC film) and a cyclic polyolefin. A combination of a resin, a combination of a cellulose resin film (such as a TAC film) and a (meth)acrylic resin film, a combination of a cyclic polyolefin resin and a (meth)acrylic resin film, and the like. Further, even if the thermoplastic resin constituting the protective film bonded to both surfaces is of the same type, the difference in moisture permeability occurs due to the presence or absence of the surface treatment layer deposited thereon or the type of the surface treatment layer.

The polarizer 10 and the first protective film 20 and the second protective film 30 can be bonded together via an adhesive layer. As the adhesive for forming the adhesive layer, a water-based adhesive, that is, a person in which the adhesive component is dissolved in water, or dispersed in water, or an active energy ray-curable adhesive can be used.

The adhesive component of the aqueous adhesive, for example, may be polyethylene An enol resin or a urethane resin. The active energy ray-curable adhesive may be, for example, an active energy ray-curable compound containing an epoxy compound or a (meth)acrylic compound, and a curable composition of a polymerization initiator. The active energy ray-curable adhesive may be a solventless adhesive, but may also contain an organic solvent. If a solventless type of adhesive is used, there is no need for a drying treatment to remove the solvent. When an active energy ray-curable adhesive is used, the protective film is bonded to the adhesive layer, and then an active energy ray such as visible light, ultraviolet light, X-ray, or electron beam is irradiated, and it is preferable to irradiate the ultraviolet light to form an adhesive layer. hardening. Then, in this case, the adhesive layer of the first polarizer sheet-like body contains a cured product of an active energy ray-curable adhesive.

The first polarizing plate sheet 1 shown in FIG. 1 includes the first protective film 20 on one surface of the polarizer 10 and the first protective film 20 when the second protective film 30 is provided on the other surface. The first adhesive layer and the second adhesive layer to which the second protective film 30 is bonded may be formed of the same type of adhesive or may be formed of different types of adhesives, but it is preferable from the viewpoint of production efficiency. It is formed by the same kind of adhesive.

When at least one of the first adhesive layer and the second adhesive layer (preferably both) contains a cured product of an active energy ray-curable adhesive, waveform defects due to moisture absorption are particularly likely to occur. Such a situation is particularly advantageous for the present invention.

Examples of the adhesive constituting the adhesive layer 40 for bonding an image display element (for example, a liquid crystal cell) include a (meth)acrylic adhesive, an urethane adhesive, and a bismuth adhesive. Polyester An adhesive, a polyamide-based adhesive, a polyether 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 when the polarizing plate is stored/carried or inspected. The separation film 50 of the protective pressure-sensitive adhesive layer 40 is actually peeled off immediately after being used for a second polarizing plate sheet to be described later (for example, bonded to an image display element such as a liquid crystal cell). Further, the protective film 60 is usually used after being supplied to the second polarizing plate sheet (for example, bonded to an image display element such as a liquid crystal cell), and the respective adhesive layers are peeled off.

The separation film 50 is usually composed of a thermoplastic resin film which is subjected to release treatment on one side, and the release-treated surface is bonded to the adhesive layer 40. Further, the protective film 60 is usually formed by providing an adhesive layer on one surface of a thermoplastic resin film. The thermoplastic resin constituting the separation film 50 and the protective film 60 may be, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, such as polyethylene terephthalate or polyethylene naphthalate. Polyester resin, etc. Regarding the adhesive layer contained in the protective film 60, the related description of the above-mentioned adhesive layer 40 is cited.

The layer configuration of the first polarizing plate sheet is not limited to the example shown in Fig. 1, and may be, for example, a layer configuration as described below.

[a] omitting the adhesive layer 40, the separation film 50, and the protective film 60 Any one or more of the configurations, [b] omitting one of the first protective film 20 and the second protective film 30, and [c] using an optical compensation film such as a retardation film as the second protective film 30, [d] A configuration of an optical compensation film having a retardation film in addition to the first protective film 20 and the second protective film 30.

An example of the above [b] is a configuration in which the second protective film 30 is omitted. A preferred embodiment is to directly laminate the adhesive layer 40 on the surface of the polarizer 10 opposite to the first protective film 20 to form a protective film. 60/layer 1 of the first protective film 20/polarizer 10/adhesive layer 40/separation film 50.

A preferred embodiment of the above [c] is a layer constitution of the protective film 60 / the first protective film 20 / the polarizer 10 / the retardation film (second protective film 30) / the adhesive layer 40 / the separation film 50. A preferred embodiment of the above [d] is a layer constitution 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. In this case, the second protective film 30 and the retardation film can be bonded together via, for example, an adhesive layer.

The retardation film is an optical film having optical anisotropy such as uniaxial or biaxial, and may be, for example, a stretched film of a thermoplastic resin. The thermoplastic resin may be a polyvinylidene fluoride/polymethyl methacrylate copolymer, a liquid crystal polyester, or an acetaminophen, in addition to the above-described first and second protective films 20 and 30. Ethylene-vinyl acetate a saponified product of a copolymer, polyvinyl chloride or the like. The stretching ratio is usually about 1.01 to 6 times.

According to the method of the present invention, when the first polarizing plate sheet is a polarizing plate sheet including an adhesive layer, the deformation problem called "reverse curling" can be suppressed unlike the waveform defect. In the polarizing plate sheet containing the adhesive layer, the adhesive layer is as shown in Fig. 1, or a preferred embodiment of the above [b] as exemplified above, which can be laminated in the protective film and the polarizer The surface on the opposite side or the surface of the polarizer may be laminated. The polarizing plate sheet containing the adhesive layer may further include a separation film laminated on the outer surface of the adhesive layer as described above.

(2) Step of obtaining a second polarizing plate sheet (water content lowering step)

In this step, the moisture content of the first polarizing plate sheet having one or more waveform defects in at least one of the long sides is lowered (drying treatment), and the second polarizing plate having the waveform defect reduced is obtained. The step of the sheet.

In this step, the moisture content of the first polarizing plate sheet is reduced by 0.05% by weight or more. In other words, when the moisture content of the first polarizer sheet-like body is S1 and the water content of the second polarizer sheet-like body is S2, the absolute value |ΔS| of the water content difference ΔS of S2-S1 becomes 0.05 weight. %the above. When ΔS| is less than 0.05% by weight, it is impossible to obtain an effect of sufficiently reducing the waveform defect. The ΔS| is preferably 0.06% by weight or more, more preferably 0.07% by weight or more. The method of measuring the moisture content S1, S2 and the moisture content difference ΔS of the polarizing plate sheet is described in the following examples.

When the first polarizing plate-like sheet is a polarizing plate-like body including the above-mentioned adhesive layer, |ΔS| is preferably less than 0.2% by weight, more preferably 0.18% by weight or less, even more preferably 0.15% by weight or less. . Thereby, "reverse curling" can be effectively suppressed. "Reverse curling" refers to a polarizing plate sheet containing an adhesive layer in a state where there is no separation film for protecting the adhesive layer (for example, a polarizing plate sheet having a separation film on the outer surface of the adhesive layer) When the body is peeled off and the separation film is removed, the polarizing plate is placed on the side of the image display element (for example, the liquid crystal cell) facing upward (that is, the adhesive layer is facing upward) on the flat table. The four corner portions of the sheet-like body are floated from the flat table, and when viewed from the side, the entire polarizing plate-like system has a U-shaped deformation. It is preferable to suppress the visibility due to the reverse curling, and it is easy to have the incorporation of bubbles or the like.

Further, the reverse curl is generally the first visible deformation in the state in which the separation layer is not present on the adhesive layer.

For example, the first polarizing plate sheet is continuously held (storage) in a low-humidity environment for a predetermined period of time as a method of appropriately lowering the water content of the first polarizing plate-like sheet. Method 2) A method of heating the first polarizing plate sheet, and the like. The heating temperature of the method 2) is, for example, about 35 to 65 °C. Among them, the quality (optical characteristics) of the obtained second polarizing plate sheet can be more favorably maintained, and the waveform defect can be easily maintained after the waveform defect is reduced. Therefore, the method 1) is preferably used.

Specific examples of the method 1) include, for example: 1-1) The method of holding (storing) the first polarizing plate sheet in the sealed container in a continuous period in a low-humidity environment, and 1-2) in the low-humidity environment, the first in the room The method of holding (storing) the polarizing plate sheet body in a continuous period, and the like. Among them, the method 1-1) is suitable because it does not require a burden on the equipment and is suitable for transportation and circulation. In a low humidity environment, for example, the relative humidity may be 20 to 55%, desirably 30 to 50%, and more desirably 35 to 50%. The temperature in a low humidity environment may be, for example, about 15 to 35 °C.

The container used in the method 1-1) is a sealable container, and may be, for example, a film package, a plastic container, a metal container or the like. In order to maintain a low-humidity environment in the interior of the container, it is preferable to use a container having a moisture-proof property, and a container having a moisture-proof layer as a representative of a multilayer film package having an aluminum layer as a moisture-proof layer.

In order to make the sealed container a low-humidity environment (reducing the relative humidity in the sealed container), a low-humidity inert gas (dry nitrogen, dry air, etc.) or a desiccant (dehumidifying agent) is sealed in a sealed container. . When an inert gas having a low humidity is used, the first polarizing plate sheet may be sealed and packaged by introducing the inert gas into the sealed container and replacing the gas in the container. When a desiccant (dehumidifying agent) is used, a desiccant is placed in a sealed container, and the package may be sealed together with the first polarizing plate sheet.

As a desiccant (dehumidifying agent), various porous bodies can be used, for example, tannin (silicone type A, tannin type B, etc.), zeolite, molecular sieve, activated carbon, activated clay, and the like. In method 1-1), in keeping (keeping) It is advantageous to maintain the relative humidity in the sealed container at a certain value within the above-mentioned relative humidity range during the period of the first polarizing plate sheet. Therefore, even among the above-mentioned desiccant (dehumidifying agent), it is preferable not only to absorb moisture but also to use a humidity-controlling agent capable of releasing moisture in accordance with the relative humidity of the surroundings. As the humidity control agent, silicone type B, zeolite, activated clay or the like can be used.

As described above, the water content reduction treatment (drying treatment) of the first polarizing plate sheet is particularly effective at a height of 2 mm or more, or a reduction in the number of waveform defects of three or more, and in any case, the height is 2 mm or less and the number is A waveform defect of less than three, or a reduction of a waveform defect of a short side is also effective.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples, but the invention is not limited by the examples. In the following examples, the number and height of the waveform defects, the height of the reverse curl, and the difference in the moisture content and the water content of the polarizing plate sheet are in accordance with the following measurement methods.

(number and height of waveform defects)

The side of the separation film 50 faces upward, and a polarizing plate sheet body is placed on the plane table, and the number of waveform defects in the two long sides of the polarizing plate sheet body is measured (as described above, the height is determined from the plane table) Waveform defects of 0.5 mm or more.), and the height from the plane of the waveform defect. In Table 1, among the two long sides, the number and height of waveform defects in the long side of many waveform defects are described. When the height of the waveform defect described in Table 1 has a plurality of waveform defects, it means the height of the highest waveform defect.

(reverse curl height)

The separation film 50 was peeled off, and the side of the adhesive layer 40 was faced upward, and a polarizing plate sheet was placed on a flat table. In this state, the height from the plane of the four corners is measured, and the maximum value of these is regarded as the height of the reverse curl.

(Moisture rate S1, S2 of the polarizing plate sheet and moisture ratio difference ΔS)

In the relationship between the measured values of the infrared absorption method and the measured value of the infrared absorption type moisture meter ("IM series 1100S" manufactured by CINO Co., Ltd.), a plurality of polarizing plate-like sample samples were used in advance. The calibration curve (conversion formula) presented was obtained by the following formula: moisture content (% by weight) by dry weight method = 22.739 × (measured value of moisture meter) + 2.5046. In this case, the weight of the polarizing plate-like sheet which was dried at 105 ° C for 2 hours was set to W1 by the moisture content of the dry weight method, and the weight of the polarizing plate-like sheet before drying was set to W0, and the following formula was used. Get: moisture content by weight (% by weight) = {(W0-W1) ÷ W0} × 100

In the following example, the moisture content S1 of the first polarizing plate sheet and the water content S2 of the second polarizing plate sheet are obtained by using the moisture meter described above, and are substituted into the calibration curve (converted formula). The moisture content (% by weight) is converted into a moisture content by a dry weight method. The difference in S1 is subtracted from S2, and the water content ratio ΔS of the water content S2 of the second polarizing plate sheet and the water content S1 of the first polarizing plate sheet is calculated.

<Example 1>

[1] Production of the first polarizing plate sheet

A long polarizing plate having a layer configuration as shown in Fig. 1 was prepared. The layer structure of the polarizing plate is a protective film 60 having a thickness of 53 μm (including a (meth)acrylic adhesive layer and a polyethylene terephthalate film)/a first protective film 20 (TAC film) having a thickness of 60 μm/ Polarizing sheet 10 having a thickness of 25 μm (uniaxially-stretched polyvinyl alcohol film adsorbing oriented iodine)/second protective film 30 having a thickness of 52 μm (phase-difference film containing cyclic polyolefin-based resin)/adhesive layer 40 having a thickness of 20 μm ( (Meth)acrylic adhesive layer)/separation film 50 having a thickness of 38 μm (polyethylene terephthalate film subjected to release treatment on one side). Each of the first protective film 20 and the second protective film 30 is an ultraviolet curable adhesive containing an active energy ray-curable adhesive (a curable compound containing a cationically polymerizable epoxy compound and a photocationic polymerization initiator), ADEKA ( The cured product of "KR-70T" manufactured by the company) is bonded to the polarizer 10 via an adhesive layer. Further, the first protective film 20 and the second protective film 30 have a moisture permeability at 40 ° C and a relative humidity of 90%, respectively, of 560 g / (m ² ‧ ²⁴ hr) and 5 g / (m ² ‧ 24 hr).

A rectangular polarizing plate sheet having a size of 46 inches (long side 1031 mm × short side 585 mm) was cut out from the long polarizing plate, and then stored in an environment of 23 ° C and a relative humidity of 55% for 7 days, according to the above measurement method. The first polarizing plate sheet having a waveform height of 1.0 mm and a number of waveform defects of three long sides was obtained.

[2] Production of the second polarizing plate sheet (water content lowering step)

In the retort bag (retort bag) with the aluminum layer as the moisture-proof layer, put in 1 While the first polarizing plate-like sheet obtained above was placed, 8 g of a humidity-control agent (silicone type B) and a hygrometer ("TR-77Ui" manufactured by T & D CORP.) were placed, and the retort pouch was sealed. This was stored in a room at a constant temperature for 7 days to obtain a second polarizing plate sheet. After storage for 7 days, the temperature and relative humidity in the retort pouch were substantially constant except for the initial storage, which were 21 ° C and 48.0%, respectively.

<Example 2>

In addition to using a first polarizing plate sheet having a waveform height of 0.5 mm and a long side with four waveform defects, 16 g of a silicone B type, and a temperature and a relative humidity of a retort stored for 7 days are set as The second polarizing plate sheet was obtained in the same manner as in Example 1 except for the above.

<Example 3>

The second polarizing plate sheet was obtained in the same manner as in Example 1 except that 32 g of the silicone B type was used, and the temperature and relative humidity in the retort pouch stored for 7 days were as shown in Table 1.

<Example 4>

The second polarizing plate was obtained in the same manner as in Example 1 except that 80 g of the silicone type A was used instead of the silicone type B, and the temperature and relative humidity in the retort pouch stored for 7 days were set as shown in Table 1. Platelet.

<Example 5>

In addition to using the first polarizing plate-like body having a long side with four waveform defects, and using 80 g of the silicone A type, the retort pouch storing the first polarizing plate-like body is replaced with a moisture-proof plastic container. And the temperature and relative humidity in the storage for 7 days are set as shown in Table 1, and the rest and the embodiment 1 In the same manner, the second polarizing plate sheet was obtained.

The moisture content S1 of the first polarizing plate sheet before the moisture content lowering step, the number and height of the waveform defects, the moisture content S2 of the second polarizing plate sheet after the moisture content lowering step, and the waveform defects The number, height, and height of the reverse curl were determined according to the methods described above. The results are shown in Table 1. The calculation result of the moisture content difference ΔS is also shown in Table 1.

1‧‧‧1st polarizing plate sheet

10‧‧‧ polarizer

20‧‧‧1st protective film

30‧‧‧2nd protective film

40‧‧‧Adhesive layer

50‧‧‧Separation film

60‧‧‧Protective film

Claims (8)

A method for producing a polarizing plate sheet includes a step of preparing a first polarizing plate-like body, wherein the first polarizing plate-like system includes a polarizing plate and a layer deposited on at least one side of the polarizing plate The protective film is a polarizing plate-like body having a square shape of a long side and a short side, and has one or more waveform defects in at least one of the long sides; and moisture of the first polarizing plate-like body The step of lowering the ratio by 0.05% by weight or more to obtain the second polarizing plate sheet. The manufacturing method according to the first aspect of the invention, wherein the first polarizing plate sheet body comprises an adhesive layer, and in the step of obtaining the second polarizing plate sheet body, the first polarizing plate sheet is formed The moisture content of the body decreased by less than 0.2% by weight. The manufacturing method according to the first or second aspect of the invention, wherein in the step of preparing the first polarizing plate sheet, the waveform defects included in at least one of the long sides are three or more. The manufacturing method according to the first or second aspect of the invention, wherein in the step of preparing the first polarizing plate sheet, the height of the waveform defect included in at least one of the long sides exceeds 2 mm. The manufacturing method according to any one of the first to fourth aspect, wherein the first polarizing plate-like system includes the polarizer, and the first layer of the polarizer is laminated on one surface thereof 1 protective film and 2nd layer deposited on the other surface via the second adhesive layer Protective film. The manufacturing method according to claim 5, wherein the first protective film and the second protective film have a moisture permeability of 30 g/(m ² ‧24 hr) or more at a temperature of 40 ° C and a relative humidity of 90%. The production method according to claim 5, wherein at least one of the first adhesive layer and the second adhesive layer is made of a cured product of an active energy ray-curable adhesive. The manufacturing method according to any one of claims 1 to 7, wherein the moisture content is reduced by sealing the first polarizing plate sheet and the humidity control agent together in the moisture-proof container.