KR102281566B1 - Polarizing plate roll - Google Patents

Abstract

A winding core having first and second projections extending in the circumferential direction on an outer circumferential surface thereof, and a polarizing plate wound around the winding core, wherein the polarizing plate includes a polarizer and a protective film laminated on at least one surface thereof , The polarizing plate roll wound around the core so that one end area|region in the width direction of a protective film may be located on a 1st convex part, and the other end area|region may be located on a 2nd convex part is provided.

Description

Polarizing plate roll {POLARIZING PLATE ROLL}

The present invention relates to a polarizing plate roll formed by winding a long polarizing plate around a core.

A polarizing plate is widely used for display apparatuses, such as a liquid crystal display device, especially in various mobile devices, such as a smart phone, in recent years. As a polarizing plate, it is common to have the structure which laminated|attached the protective film on one side or both surfaces of a polarizer, but thin film formation of the polarizer and protective film which comprises a polarizing plate is requested|required as it develops into mobile devices.

In the manufacture of a polarizing plate, a long (belt-shaped) raw material film is used and the raw material film is unwound from a roll in which the raw material film is wound on a winding core (winding core), while processing the unwound raw material film to obtain a long (belt-shaped) raw material film. It is common to set it as the polarizing plate of ), and to wind up the obtained polarizing plate to a core to make a roll, what is called a roll-to-roll system. Therefore, a polarizing plate is usually obtained as a polarizing plate roll which wound up the elongate polarizing plate around the core (for example, Unexamined-Japanese-Patent No. 2013-029754 (patent document 1)).

Patent Document 1: Japanese Patent Application Laid-Open No. 2013-029754

As described above, the polarizing plate is generally manufactured in the form of a polarizing plate roll. For example, when the film length of the polarizing plate is 2000 m and the diameter of the core is 150 mmφ, the number of turns of the polarizing plate reaches about 4000.

A polarizing plate manufactured as a polarizing plate roll is maintained in a roll state for a certain continuous period, such as between until it is provided for a subsequent process such as further bonding of other films or forming a coating layer, or between transport to a supplier often becomes

However, there existed a problem that the polarizing plate unwound after being maintained in a roll state for a certain continuous period was easy to accompany the problem called "winding stem defect". This problem is so remarkable that the polarizer and protective film which comprise a polarizing plate are thin. Referring to FIG. 7 , "winding stem defect" is a stem extending in the width direction of the polarizing plate, which is generated by pressing the polarizing plate wound on the height difference, that is, the step portion that occurs between the winding start end of the polarizing plate and the outer peripheral surface of the winding core. It is a shape depression defect. In the case where the polarizing plate is wound after fixing the winding start end of the polarizing plate to the core using a fixing member such as a double-sided tape, the winding stem defect is particularly conspicuous. As shown in FIG. 7 , the winding stem defect is a defect K ₁ (short side edge of the end) originating in the corner at the beginning of winding of the polarizing plate (the corner at the beginning of winding of the polarizing plate by being pressed against it. defect) and, when the fixing member is used, also includes a defect K ₂ (defect caused by being pressed against the edge of the fixing member) originating in the corner portion of the fixing member.

The winding stem defect is strongly generated in the polarizing plate (polarizing plate at the initial start of winding) on the inside of the polarizing plate roll and becomes weaker toward the outside of the polarizing plate roll, but may occur over several tens of meters in the longitudinal direction from the start of winding of the polarizing plate. When a polarizing plate containing a winding stem defect is applied to an image display device such as a liquid crystal display device, there is a fear that visibility may decrease, and if the polarizing plate portion having the defect is removed as a defective product, the product yield of the polarizing plate will greatly decrease.

Then, this invention is a polarizing plate roll formed by winding a polarizing plate around a core, Comprising: An object of this invention is to provide the polarizing plate roll which can suppress the "winding stem defect" which can be confirmed when unwinding a polarizing plate from the roll.

The present invention provides a polarizing plate roll described below.

[1] A winding core having a first convex portion and a second convex portion extending in the circumferential direction on an outer circumferential surface thereof, and a polarizing plate wound around the winding core,

The polarizing plate includes a polarizer and a protective film laminated on at least one surface thereof,

The said polarizing plate roll is wound around the said core so that one end area|region in the width direction of the said protective film may be located on the said 1st convex part, and the other end area|region may be located on the said 2nd protrusion.

[2] In the polarizing plate, one end in the width direction of the polarizer is located inside the inner end of the first convex portion, and the other end is located inside the inner end of the second convex portion. The polarizing plate roll as described in [1] wound around.

[3] The polarizing plate roll according to [1] or [2], wherein the winding start end of the polarizing plate is fixed to the outer peripheral surface using a fixing member.

[4] The polarizing plate roll according to any one of [1] to [3], wherein the height of the first convex portion and the second convex portion is 50 µm or more, respectively.

[5] The polarizing plate roll according to any one of [1] to [4], wherein the first convex portion and the second convex portion are constituted by a resin film adhered to the outer peripheral surface.

ADVANTAGE OF THE INVENTION According to this invention, the polarizing plate roll which can suppress winding-up stem defect can be provided. By suppressing the winding stem defect, the product quality or product yield of a polarizing plate can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the winding core which has a convex part used for the polarizing plate roll which concerns on this invention.
Fig. 2 is a cross-sectional view of a portion having a first convex portion of a winding core having a convex portion shown in Fig. 1;
3 is a cross-sectional view schematically showing an example of a positional relationship in the width direction between a convex portion of a winding core having a convex portion and a wound polarizing plate.
Fig. 4 is a cross-sectional view schematically showing another example of the positional relationship in the width direction between the convex portion of the winding core having the convex portion and the wound polarizing plate.
5 is a cross-sectional view showing another example of a winding core having a convex portion.
6 is a schematic view showing a state in which a winding start end of a polarizing plate is fixed to a core having a convex portion using a fixing member.
7 is a schematic diagram for explaining a winding stem defect.

A polarizing plate roll according to the present invention, as shown in FIGS. 1 and 2 an example thereof, as a winding core, having a first convex portion 10a and a second convex portion 10b extending in the circumferential direction on the outer peripheral surface It is a roll-shaped polarizing plate formed by winding a long polarizing plate on this using the winding core 10 which has a convex part. In this invention, in order to suppress generation|occurrence|production of the "winding stem defect" mentioned above, as for a polarizing plate, one end area|region in the width direction of the protective film which comprises this is located on the 1st convex part 10a, and the other It is wound around the core 10 having the convex portion so that the end region is located on the second convex portion 10b. The positional relationship with respect to the width direction between the convex parts 10a, 10b of the winding core 10 with a convex part and the polarizing plate to be wound is demonstrated in detail in the following (3) term.

(1) Winding core with convex part

The winding core 10 having the convex portion may have the same shape as a conventionally known winding core, except that it has the first convex portion 10a and the second convex portion 10b, and the body portion of the winding core except for these convex portions is , such as cylindrical or cylindrical. There is no restriction|limiting in particular also in a material, A metal, an alloy, and resin (thermoplastic resin, etc.) can be used. The length in the width direction (rotation axis direction) of the winding core 10 having the convex portion is equal to or longer than the width of the wound polarizing plate. When the winding core 10 having the convex portion is cylindrical or cylindrical, the diameter may be a general diameter of the winding core, and is, for example, about 100 to 200 mmφ.

The installation positions of the first convex part 10a and the second convex part 10b formed on the outer peripheral surface of the winding core 10 having the convex part depend on the width of the polarizing plate to be wound. Specifically, the first convex portion 10a and the second convex portion 10b have positions different from each other on the outer peripheral surface, and one end region in the width direction of the protective film constituting the polarizing plate is the first convex portion. It is located on the part 10a, and is provided so that the other end area|region may be located on the 2nd convex part 10b. As shown in Fig. 1, the first convex portion 10a and the second convex portion 10b are usually an end region (including the end portion) in the width direction (rotation axis direction) of the winding core 10 having the convex portion; or formed near the end.

The first convex portion 10a and the second convex portion 10b are formed so as to extend in the circumferential direction of the winding core 10 having the convex portion on the outer peripheral surface of the winding core 10 having the convex portion, preferably the convex portion It extends parallel to the circumferential direction of the core 10 with the convex portion (in the direction perpendicular to the direction of the rotation axis of the core 10 with the convex portion). As shown in Fig. 2, the first convex portion 10a and the second convex portion 10b are preferably in the shape of a belt, and are formed on the entire circumference or approximately the entire circumference of the outer peripheral surface of the winding core 10 having the projections. It is preferably formed in an annular shape over.

The first convex portion 10a and the second convex portion 10b may be integrally formed with the main body portion of the winding core 10 having the convex portion, or are formed using a separate member different from the main body portion. good to be As a method of forming the convex portion using a separate member, the first convex portion 10a and the second convex portion 10b are formed on the outer peripheral surface of the cylindrical or cylindrical winding core as the main body portion of the winding core 10 having the convex portion. The method of sticking the resin film (for example, the film tape which consists of a thermoplastic resin) to form is mentioned. This resin film may have an adhesive layer on one surface for adhesion to the outer peripheral surface of a winding core. According to the method of sticking a resin film using an adhesive, since it becomes possible to fix and stick, the position adjustment or position change of a convex part becomes easy. The method of forming the convex portion by adhesion of the resin film is advantageous in terms of manufacturing cost and manufacturing simplicity of the winding core 10 having the convex portion, and furthermore, the winding core 10 having the convex portion having sufficient strength can be obtained. there is. The resin film may be adhered to the outer peripheral surface of the winding core using an adhesive.

(2) Polarizer

The polarizing plate wound around the core 10 with a convex part is equipped with a polarizer and the protective film laminated|stacked on the at least one surface. A protective film may be laminated|stacked on both surfaces of a polarizer. The protective film is usually bonded to the polarizer through an adhesive layer. As the adhesive, an active energy ray-curable adhesive such as an ultraviolet curable adhesive or a water-based adhesive such as an aqueous polyvinyl alcohol-based resin solution can be used. The overall thickness of the polarizing plate is generally about 30 to 300 μm.

As a polarizer, what carried out the adsorption|suction orientation of the dichroic dye to the polyvinyl alcohol-type resin uniaxially stretched can be used suitably. As a dichroic dye, iodine or a dichroic dye can be used. As polyvinyl alcohol-type resin which comprises a polarizer, what saponified polyvinyl acetate-type resin can be used. As polyvinyl acetate-type resin, the copolymer of vinyl acetate and other monomer copolymerizable to this other than polyvinyl acetate which is a homopolymer of vinyl acetate is illustrated. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group. In this specification, "(meth)acryl" means at least one chosen from acryl and methacryl. The same applies to "(meth)acryloyl".

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal and polyvinyl acetal modified with aldehydes may be used. The polymerization degree of polyvinyl alcohol-type resin is about 1000-10000 normally, and about 1500-5000 is preferable.

The polarizer is a step of uniaxially stretching (typically, longitudinal uniaxial stretching in the longitudinal direction of the film) of the raw film made of the polyvinyl alcohol-based resin, dyeing the polyvinyl alcohol-based resin film with a dichroic dye to obtain the dichroic dye It can manufacture by the method including the process of making it adsorb|suck, the process of treating the polyvinyl alcohol-type resin film to which the dichroic dye has adsorbed with the aqueous boric acid solution, and the process of washing with water after the process with boric acid aqueous solution. You may provide the swelling process which performs the process of immersing in water before a dyeing process.

Uniaxial stretching of a polyvinyl alcohol-type resin film can be performed before dyeing of a dichroic dye, simultaneously with dyeing, or after dyeing|staining. When performing uniaxial stretching after dyeing|staining, you may perform this uniaxial stretching before a boric-acid process or during a boric-acid process. Moreover, you may perform uniaxial stretching in these several steps.

The thickness (average thickness in the overall width) of the polarizer is, for example, 40 µm or less, preferably 25 µm or less, more preferably 20 µm or less, and in particular, in a polarizing plate for mobile devices, the viewpoint of thinning the polarizing plate It is more preferable that it is 10 μm or less. The thickness of a polarizer is 2 micrometers or more normally. Even when such a thin film polarizer is used, according to the present invention, winding stem defects can be effectively suppressed.

The protective film bonded to the polarizer is a translucent (preferably optically transparent) thermoplastic resin, for example, a polyolefin such as a chain polyolefin-based resin (polypropylene-based resin, etc.) or a cyclic polyolefin-based resin (norbornene-based resin, etc.) based resin; Cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; polyester-based resin; polycarbonate-based resin; (meth)acrylic resin; polystyrene-based resin; Or it may be a film made of a mixture or copolymer thereof. When a protective film is bonded on both surfaces of a polarizer, the protective film which consists of mutually same kind of resin may be sufficient as these, and the protective film which consists of different kinds of resin may be sufficient.

The protective film may be a protective film having an optical function such as a retardation film or a brightness improving film. For example, by stretching the film made of the thermoplastic resin (uniaxial stretching or biaxial stretching, etc.) or forming a liquid crystal layer or the like on the film, a retardation film to which an arbitrary retardation value is provided can be obtained.

As chain polyolefin resin, the copolymer which consists of 2 or more types of chain olefin other than the homopolymer of a chain olefin like a polyethylene resin and a polypropylene resin is mentioned.

Cyclic polyolefin-type resin is a generic name of resin superposed|polymerized using cyclic olefin as a polymerization unit. Specific examples of the cyclic polyolefin resin include a ring-opened (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer of a cyclic olefin and a chain olefin such as ethylene and propylene (typically a random copolymer) and unsaturated Graft polymers modified with carboxylic acids or derivatives thereof, and hydrides thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers are preferably used as cyclic olefins.

Cellulose ester-based resins are esters of cellulose and fatty acids. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, these copolymers and the thing by which a part of hydroxyl group was modified by other substituents can also be used. Among these, cellulose triacetate (triacetyl cellulose: TAC) is especially preferable.

Polyester-type resin is resin other than the said cellulose-ester-type resin which has an ester bond, and what consists of polycondensate of polyhydric carboxylic acid or its derivative(s), and polyhydric alcohol is common. As polyhydric carboxylic acid or its derivative, dicarboxylic acid or its derivative can be used, For example, terephthalic acid, isophthalic acid, dimethyl terephthalate, naphthalenedicarboxylic acid dimethyl, etc. are mentioned. Diol can be used as polyhydric alcohol, For example, ethylene glycol, propanediol, butanediol, neopentyl glycol, cyclohexane dimethanol, etc. are mentioned.

Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexane. dimethyl naphthalate.

The polycarbonate-based resin is composed of a polymer to which a monomer unit is bonded through a carbonate group. The polycarbonate-based resin may be a resin called a modified polycarbonate, a copolymer polycarbonate, or the like having a polymer skeleton modified.

(meth)acrylic-type resin is resin which uses the compound which has a (meth)acryloyl group as a main structural monomer. Specific examples of the (meth)acrylic resin include poly(meth)acrylic acid esters such as polymethyl methacrylate; methyl methacrylate-(meth)acrylic acid copolymer; methyl methacrylate-(meth)acrylic acid ester copolymer; methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin, etc.); copolymers of methyl methacrylate and a compound having an alicyclic hydrocarbon group (eg, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-(meth) acrylate norbornyl copolymer, etc.) . Preferably, the poly (meth) poly (meth) acrylic acid C _{1 -6} The polymer is used as a main component, alkyl ester, more preferably the meta main component methyl methacrylate (50 to 100% by weight, preferably, such as methyl acrylate Preferably 70 to 100% by weight) of a methyl methacrylate-based resin is used.

From a viewpoint of thickness reduction of a polarizing plate, the thickness of a protective film becomes like this. Preferably it is 90 micrometers or less, More preferably, it is 50 micrometers or less, More preferably, it is 30 micrometers or less. The thickness of a protective film is 5 micrometers or more normally from a viewpoint of intensity|strength and handleability. Even when such a thin protective film is used, according to the present invention, winding stem defects can be effectively suppressed.

A polarizing plate may contain films and layers other than a protective film. Specific examples of films and layers other than the protective film include an adhesive layer; a separate film (release film) that protects the outer surface of the pressure-sensitive adhesive layer; The protection film which protects the surface of a protection film (surface protection film); a surface treatment layer (coating layer) for imparting various functions to the polarizing plate; Various optical function films are included.

As the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, a conventionally known appropriate pressure-sensitive adhesive can be used, for example, (meth)acrylic pressure-sensitive adhesive, urethane pressure-sensitive adhesive, silicone pressure-sensitive adhesive, polyester-based pressure-sensitive adhesive, polyamide-based pressure-sensitive adhesive, polyether-based pressure-sensitive adhesive, fluorine-based pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive An adhesive etc. are mentioned. Especially, from viewpoints, such as transparency, adhesive force, reliability, rework property, a (meth)acrylic-type adhesive is used preferably. The thickness of the pressure-sensitive adhesive layer may be generally 1 to 40 μm (eg, 3 to 25 μm).

The material of the separator film may be a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Especially, the stretched film of polyethylene terephthalate is preferable.

Examples of the constituent material of the protection film include polyethylene-based resins such as polyethylene, polypropylene-based resins such as polypropylene, and polyester-based resins such as polyethylene terephthalate. Among them, polyethylene terephthalate from the viewpoint of moisture permeability and mechanical strength. of the stretched film is preferred.

Examples of the surface treatment layer include a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer.

Examples of the optical function film include a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light exhibiting the opposite property; A film having an anti-glare function having an uneven shape on the surface; film with surface anti-reflection function; a reflective film having a reflective function on the surface; a transflective film having both a reflective function and a transmissive function; A viewing angle compensation film is mentioned.

Although the width in particular of the polarizing plate wound around the core 10 with a convex part is not restrict|limited, Usually, it is about 300-2500 mm, More typically, it is about 500-2000 mm. Moreover, the length in particular of a polarizing plate is also although it does not restrict|limit, Usually, it is about several hundred m - about 3000 m (for example, about 2000 m), More typically, it is about 1500-2500 m. Although the width of the polarizer and the width of the protective film bonded thereto may be the same or different, the width of the protective film is made larger so that both ends (both end surfaces) in the width direction of the protective film are outside the width direction both ends (both end surfaces) of the polarizer It is common to bond a protective film so that it is located on the

(3) Positional relationship in the width direction between the convex part of the winding core having the convex part and the polarizing plate to be wound

3 : is sectional drawing which shows typically an example of the positional relationship regarding the width direction between the convex part of the winding core 10 which has a convex part, and the polarizing plate 20 to be wound. In FIG. 3, as an example, the polarizing plate 20 comprised with the polarizer 21, the 1st protective film 22 bonded to the one surface, and the 2nd protective film 23 bonded to the other surface is used. Although the case is shown, the layer structure of a polarizing plate is not limited to this as mentioned above. In addition, although FIG. 3 employ|adopts only the 1st convex part 10a of the winding core 10 which has a convex part, the content demonstrated below is similarly applied about the positional relationship with the 2nd convex part 10b.

The polarizing plate roll of this invention WHEREIN: As for the polarizing plate 20, although one edge part area|region in the width direction of a protective film is located on the 1st convex part 10a, and is not shown in FIG. 3, the other edge part It is wound around the core 10 having the convex portion so that the region is located on the second convex portion 10b. When protective films (first and second protective films 22 and 23) are provided on both surfaces of the polarizer 21 as in the example of FIG. 3 , the protective films of both sides are wound so as to satisfy the above positional relationship. desirable.

As in the example shown in FIG. 3 that one edge part area|region of a protective film is located on the 1st convex part 10a, the edge part (end surface, T ₁ in FIG. 3) of a protective film is 1st convex part. in addition, if positioned on the portion (10a), the end of T ₁ is the distal end T ₂ end end region in the vicinity of T ₁ in all but located on the outside, a protective film of the first convex portion (10a) of the protective film, the first projections This includes the case of being placed on the portion 10a. T end is the end area of _the vicinity of the protective film, an area of up to 15% of the polarizer with respect to the respective width end. Accordingly, it is possible to obtain a winding stem defect suppression effect. That the end T ₁ of the protective film is located on the first convex portion 10a means that the end T ₁ is located between _{the outer end T 2} and the inner end T ₃ of the first convex portion 10a (T ₁ matches T ₂ or T ₃ ). When the edge part T ₁ of a protective film is located inside the inner edge part (end surface) T ₃ of the 1st convex part 10a, it is difficult to acquire the winding-up stem defect suppression effect.

In obtaining the winding stem defect suppression effect polarizing plate 20, as illustrated in Figure 3, than the end portion T ₄ in the width direction of the polarizer 21, the inner end T ₃ of the first projections (10a) It may be wound around the core 10 having a convex portion so as to be located inside, and as shown in FIG. 4 , the end T ₄ of the polarizer 21 is located on the first convex portion 10a, that is, the polarizer 21 ) so that the end T ₄ of the first convex portion 10a is located between _{the outer end T 2} and the inner end T ₃ of the first convex portion 10a (including the case where _{T 1} coincides with T ₂ or T _{3 ).} (10) may be wound. Preferably the former.

_{3 and 4, the width W 2} (overlapping width of the protective film and the first convex portion 10a) of the end region of the protective film positioned on (riding on) the first convex portion 10a is, It is preferable that it is 5 mm or more, and it is more preferable that it is 10 mm or more. When the overlap width W ₂ is too small, it is difficult to obtain a sufficient winding stem defect suppression effect. The upper limit of the overlapping width W ₂ is not particularly limited, for example, it may be about 30 mm. _{The width W 1} of the first convex portion 10a is preferably 5 mm or more so as to obtain the desired overlapping width W _{2 .} The upper limit of the width W ₁ is not particularly limited, and is, for example, 100 mm.

In order to obtain the winding-up stem defect suppression effect more effectively, it is preferable that the height H of the 1st convex part 10a shall be 50 micrometers or more. The upper limit of the height H may be 1500 μm (eg 1000 μm). For example, when forming a convex part by adhesion of a resin film, as shown in FIG. 5, in order to increase height H, you may overlap and wind up the resin film in multiple layers. 5 is an example in which the first convex portion (10a) by winding overlaps the second resin film, t ₂ t ₁ on the first resin film. In the case of overlapping a plurality of resin films, it is preferable to displace the seams without matching them, as shown in FIG. 5 . If matched, the connected seam can be a factor in winding stem defects.

As shown in FIG. 4 , when the end T ₄ of the polarizer 21 is located on the first convex portion 10a, in order to more effectively obtain the winding stem defect suppression effect, the end T ₄ is the first convex portion as compared with the case of an inner end located on an inner side than the T ₃ in (10a), the first is preferred to be lower than the height H of the convex portion (10a). That is, the thickness of the polarizer 21 positioned on the first convex portion 10a increases the height difference (step difference portion) generated between the winding start end of the polarizing plate and the outer peripheral surface of the winding core, which is a factor of winding stem defects, It is advantageous for winding stem defect suppression to make the height H of the 1st convex part 10a lower, for example to 400 micrometers or less, and further 200 micrometers or less.

On the other hand, when the end T ₄ of the polarizer 21 is located inside the inner end T ₃ of the first convex portion 10a, in order to more effectively obtain the winding stem defect suppression effect, the first convex portion 10a It is preferable to make the height H relatively high, for example, 150 micrometers or more, Furthermore, it is preferable to set it as 300 micrometers or more.

As described above, it is common to bond the protective film so that both ends of the protective film in the width direction are positioned outside the width direction both ends of the polarizer by making the width of the protective film larger. Referring to FIG. 3 , the protective film ( _{The protrusion width W 3} of the first protective film 22 and the second protective film 23 _{(the distance from the end T 1} of the protective films 22 and 23 to the end T ₄ of the polarizer 21) is 1 to 100 mm accuracy (eg, about 5 to 60 mm).

(4) Fixing of the polarizing plate winding start end to the winding core having a convex part

The polarizing plate 20 is wound by rotating the core 10 having the convex part about its rotation axis. At this time, as shown in FIG. 6 , before starting winding, by using the fixing member 30 [ FIG. 6 ( a ) ], the winding start end (longitudinal end) of the polarizing plate 20 has a convex part It is preferable to fix it to the outer peripheral surface of the core 10 (Fig. 6(b)). Since the polarizing plate 20 can be easily fixed, a double-sided tape can be preferably used as the fixing member 30 . For example, a fixing member 30, which is a double-sided tape, is adhered to the outer peripheral surface of the winding core 10 having a convex portion parallel to the rotation axis of the winding core 10 having a convex portion, and the winding start end of the polarizing plate 20 is placed thereon, a polarizing plate ( 20) is adhered so that the direction of the short side is parallel to the axis of rotation of the winding core 10 having the convex portion. By fixing the winding start end of the polarizing plate 20 to the winding core 10 having a convex portion, especially the polarizing plate 20 in the initial stage can be smoothly wound. When the winding start end of the polarizing plate 20 is fixed to the winding core 10 having a convex part using a fixing member, a difference in height (step difference) between the winding starting end of the polarizing plate 20 and the outer peripheral surface of the winding core 10 having a convex part Since the winding stem defects are likely to occur, according to the present invention, it is possible to effectively suppress the winding stem defects even in such a case.

Example

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited by these examples.

<Comparative Example 1>

A first protective film made of triacetyl cellulose (TAC) [thickness 40 µm] / adhesive layer / polarizer formed by adsorbing and orienting a dichroic dye to a polyvinyl alcohol-based resin film uniaxially stretched longitudinally [thickness 28 µm] / adhesive layer / A long polarizing plate consisting of a layered configuration of a second protective film [thickness 40 μm] made of TAC / protection film [thickness 62 μm] made of stretched polyethylene phthalate is continuously produced by a roll-to-roll method, and a columnar core (convex No part), and the polarizing plate roll was obtained. Specific conditions for producing a polarizing plate roll are as follows. Moreover, the winding start end (longitudinal end) of the polarizing plate was fixed to the outer peripheral surface of the core using the double-sided tape of 176 micrometers in thickness.

[1] Cylindrical winding core (without projections)

·Material: FRP (fiber-reinforced plastic),

·Width direction (rotation axis direction) length: 1480 mm,

Diameter: 167 mmφ,

[2] Polarizing plate

・Width of protective film: 1330 mm,

Width of polarizer: 1270 mm,

(Both ends) 30 mm,: · W ₃ in Fig. 3

·Polarizer length: about 2000 m,

·Tension when winding the polarizer: 60 N.

<Comparative Examples 2 to 4>

A polarizing plate roll was produced in the same manner as in Comparative Example 1, except that the tension at the time of winding up the polarizing plate was 100 N (Comparative Example 2), 150 N (Comparative Example 3), and 250 N (Comparative Example 4), respectively.

<Example 1>

A polarizing plate roll was produced in the same manner as in Comparative Example 1 except that the winding core having a convex portion as shown in Fig. 1 was used and the specific conditions in polarizing plate roll production were set as follows. The polarizing plate was wound so that one end area|region in the width direction of the protective film bonded on both surfaces of a polarizer might be located on a 1st convex part, and the other end area|region might be located on a 2nd convex part. However, as shown in Fig. 3, the end T _{4 of the polarizer 21 is located inside the inner end T 3} of the first convex portion 10a and the second convex portion 10b (the polarizer and the convex portion overlap) not to be) recommended. The first and second convex portions of the winding core having the convex portions are, as shown in FIG. 5, a resin film tape of a certain width having a pressure-sensitive adhesive layer on one side is adhered to the outer circumferential surface of the core body portion over almost the entire perimeter, and On the outer peripheral surface, a resin film tape of the same width having an adhesive layer on one surface was formed by displacing the seam by about 15 mm and sticking it over almost the entire periphery.

[1] Winding core with convex part (body part: columnar)

·Material: FRP (fiber-reinforced plastic),

·Width direction (rotation axis direction) length: 1480 mm,

・The diameter of the body part: 167 mmφ,

Width of the first and second convex portions (W ₁ in FIG. 3 ): 10 mm;

- Height of 1st and 2nd convex part (H in FIG. 3): 360 micrometers,

[2] Polarizing plate

・Width of protective film: 1330 mm,

Width of polarizer: 1270 mm,

·Protrusion width of the protective film (W ₃ in Fig. 3 ): 30 mm (both ends);

·Polarizer length: about 2000 m,

·Tension when winding the polarizer: 60 N,

[3] Positional relationship between the polarizing plate and the winding core having a convex part

· The overlapping width of the protective film on both sides and the first and second convex portions (W ₂ in FIG. 3 ): 10 mm,

· The overlap width between the polarizer and the first and second convex portions: 0 mm.

<Examples 2-3>

A polarizing plate roll was produced in the same manner as in Example 1 except that the tension at the time of winding up a polarizing plate was 150N (Example 2) and 250N (Example 3), respectively.

<Example 4>

In the same manner as in Example 1, except that the tension at the time of winding the polarizing plate was 150 N, three layers of resin film tape were wound, and the height (H in Fig. 3) of the first and second convex portions was 540 µm. Thus, a polarizing plate roll was produced.

<Example 5>

A polarizing plate roll was produced in the same manner as in Comparative Example 1 except that the winding core having a convex portion as shown in Fig. 1 was used and the specific conditions in polarizing plate roll production were set as follows. The polarizing plate was wound so that one end area|region in the width direction of the protective film bonded on both surfaces of a polarizer might be located on a 1st convex part, and the other end area|region might be located on a 2nd convex part. In the present embodiment, as shown in FIG. 4 , one end T ₄ in the width direction of the polarizer 21 is located on the first convex portion 10a, and the other end T ₄ is the second convex portion. It was wound so that it might be located on the part 10b. The first and second convex portions of the winding core having the convex portions were formed by sticking a resin film tape of a certain width having an adhesive layer on one side thereof to the outer peripheral surface of the core body portion as shown in FIG. 2 over almost the entire periphery.

[1] Winding core with convex part (body part: columnar)

·Material: FRP (fiber-reinforced plastic),

·Width direction (rotation axis direction) length: 1480 mm,

・The diameter of the body part: 167 mmφ,

Width of the first and second convex portions (W ₁ in FIG. 4 ): 10 mm;

- The height of the 1st and 2nd convex part (H in FIG. 4): 360 micrometers,

[2] Polarizing plate

・Width of protective film: 1330 mm,

Width of polarizer: 1270 mm,

·Protrusion width of the protective film (W ₃ in Fig. 3 ): 30 mm (both ends);

·Polarizer length: about 2000 m,

·Tension when winding the polarizer: 250 N

[3] Positional relationship between the polarizing plate and the winding core having a convex part

· The overlapping width of the protective film on both sides and the first and second convex portions (W ₂ in FIG. 4 ): 10 mm,

· The overlap width between the polarizer and the first and second convex portions ( _{distance from the end T 4} in FIG. 4 to the inner end T ₃ of the convex portion): 10 mm.

<Example 6>

A polarizing plate roll was produced in the same manner as in Example 5 except that the height (H in Fig. 4) of the first and second convex portions was 180 µm.

Table 1 put together the main manufacturing conditions of the polarizing plate roll in Examples 1-6 and Comparative Examples 1-4. After storing the produced polarizing plate roll in the environment of 25 degreeC 50%RH for 15 days, the polarizing plate roll was unwound, and the generation|occurrence|production length of the winding-up stem defect from the start of winding of a polarizing plate was measured. A result is shown in Table 1.

DESCRIPTION OF SYMBOLS 10: winding core with a convex part, 10a: 1st convex part, 10b: 2nd convex part, 20: polarizing plate, 21: polarizer, 22: 1st protective film, 23: 2nd protective film, 30: fixing member.

Claims (9)

A winding core having a first convex portion and a second convex portion extending in a circumferential direction on an outer peripheral surface thereof, and a polarizing plate wound around the winding core,
The polarizing plate includes a polarizer and a protective film laminated on at least one surface thereof,
The polarizing plate is wound around the core so that one end region in the width direction of the protective film is located on the first convex portion and the other end region is located on the second convex portion, and further A polarizing plate roll wound around the core so that one end of the polarizer in the width direction is located inside the inner end of the first convex portion and the other end is located inside the inner end of the second convex portion. The polarizing plate roll according to claim 1, wherein a winding start end of the polarizing plate is fixed to the outer peripheral surface using a fixing member. The polarizing plate roll according to claim 1, wherein a height of the first convex portion and the second convex portion is 50 μm or more, respectively. The polarizing plate roll according to claim 2, wherein a height of the first convex portion and the second convex portion is 50 μm or more, respectively. The polarizing plate roll according to any one of claims 1 to 4, wherein the first convex portion and the second convex portion are composed of a resin film adhered to the outer peripheral surface. delete delete delete delete

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