KR102161886B1 - Method for manufacturing polarizing plate and equiment of manufacfuring polarizing plate - Google Patents

Abstract

The present invention relates to a method for manufacturing a polarizing plate and an apparatus for manufacturing a polarizing plate including the step of separating a mask film and a release film having through holes.

Description

Polarizing plate manufacturing method and polarizing plate manufacturing apparatus {METHOD FOR MANUFACTURING POLARIZING PLATE AND EQUIMENT OF MANUFACFURING POLARIZING PLATE}

The present invention relates to a method for manufacturing a polarizing plate and an apparatus for manufacturing a polarizing plate.

Polarizing plates are applied to various display devices such as liquid crystal display devices and organic light emitting devices. The polarizing plate that is currently mainly used is after dyeing iodine and/or dichroic dye on a polyvinyl alcohol (PVA)-based film, and then crosslinking the iodine and/or dichroic dye using boric acid, and stretching It is used in a form in which a protective film is laminated on one or both sides of a PVA polarizer manufactured by oriented in the manner described above.

Meanwhile, recently, display devices are becoming more and more slimmer, and in order to implement a large screen, a bezel portion and an edge thickness on which the screen is not displayed are being minimized. In addition, in order to implement various functions, components such as cameras are being mounted on display devices, and attempts have been made to impart various colors to product logos or border areas in consideration of design factors.

However, in the case of a conventional polarizing plate, the polarizing plate is dyed with iodine and/or a dichroic dye in the entire area of the polarizing plate, so that the polarizing plate shows a dark black color. In this case, the polarizing plate absorbs 50% or more of the amount of light, thereby causing problems such as lowering the visibility of the camera lens.

In order to solve this problem, methods of physically removing a partial region of a polarizing plate by punching or cutting have been used. However, in the process of punching or cutting the polarizing plate as described above, a problem of tearing the polarizing plate may occur, and according to the recent trend that the thickness of the polarizing plate is becoming thinner, such a problem is intensifying. In addition, in order to perform punching or cutting without damaging the polarizing plate, the area to be punched or cut must maintain a sufficient distance from the edge of the polarizing plate, but in this case, there is a problem that it is not suitable for the recent design trend to reduce the bezel area. .

A method of locally decolorizing a polyvinyl alcohol polarizer using a strong base solution without physical punching or cutting is known.

Japanese Public Publication 2003-121644

In the process of separating the mask film and the release film having through holes, the present invention prevents the through holes from being torn or pushed at the interface between the mask film and the release film, and furthermore, in the process of laminating the mask film and the polarizer, cracks occur in the polarizer. It is intended to provide a method of manufacturing a polarizing plate in which a localized decolorization area is formed by preventing the phenomenon that the through hole is torn or the interface between a mask film and a polarizer from being pushed, and an apparatus for manufacturing the polarizing plate. Specifically, it is intended to provide a chemical method with excellent ease of performing a continuous process and excellent stability of a continuous process.

In one aspect, the present invention comprises the steps of (S1) preparing a laminate (A) in which a release film and a mask film having a through hole are stacked;

(S2) transferring the laminate (A) to the second mask film guide roll (M2) to separate the release film and the mask film;

(S3) transferring the separated mask film to the first mask film guide roll (M1); And

(S4) Including the step of transferring the separated release film to the release film roll (R1) side,

The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 A method of manufacturing a polarizing plate having an angle (C) of 15° to 140° formed by a line connecting the center of rotation of) is provided.

At this time, the center of rotation refers to a point located at the center in the vertical section of the roll with respect to the rotation axis of the roll.

In addition, the manufacturing method of the present invention, if necessary, the laminate (A) further comprises a pressure-sensitive adhesive layer between the release film and the mask film, in the step S2, the mask to which the release film and the pressure-sensitive adhesive layer are attached It can be separated by a film.

At this time, the mask film having the through hole is a polyethylene (PolyEthylene, PE) film, a polypropylene (PP) film, a polyethylene terephthalate (PET) film, an ethylene vinyl acetate (EVA) film or a poly It may be a vinyl acetate (PolyVinyl Acetate) film.

In addition, step S1 may be to integrally penetrate the release film and the mask film to form a laminate (A).

In addition, in step S1, a through hole may be formed using a laser or a die cut.

In addition, the manufacturing method of the present invention may further include a step of attaching the separated mask film and the polarizer, if necessary. In this case, a protective film may be attached to one surface of the polarizer.

In addition, the manufacturing method of the present invention may further include a step of decolorizing the polarizer and the mask film by contacting a decolorizing solution, if necessary.

At this time, the decolorization solution is preferably a strong base having a pH of 11 to 14, and more specifically, sodium hydroxide (NaOH), sodium sulfate (NaSH), sodium azitide (NaN ₃ ), potassium hydroxide (KOH) , Potassium sulfate (KSH) and potassium thiosulfate (KS ₂ O ₃ ) It may be to include one or more bleaching agents selected from the group consisting of. Meanwhile, the viscosity of the bleaching solution may be about 1 cP to 2000 cP, and the bleaching solution may contain 1% to 30% by weight of a bleaching agent based on the total weight.

In addition, the manufacturing method of the present invention may further include washing with an alcohol or acid solution after the decolorizing step, if necessary.

In addition, the manufacturing method of the present invention may further include removing the mask film after the decolorizing step, if necessary.

In another aspect, the present invention is a second mask film guide roll (M2) for separating the laminate (A) in which a release film and a mask film having a through hole are stacked into the release film and the mask film;

A first mask film guide roll (M1) rotating the direction of the separated mask film; And

Including a release film roll (R1) winding the separated release film,

The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 A polarizing plate manufacturing apparatus with an angle (C) of 15° to 140° formed by a line connecting the rotation center of) is provided.

According to the present invention, the angle between the rolls is adjusted in the process of peeling the release film of the mask film having the through hole used to manufacture the polarizing plate having the localized decolorization region through chemical treatment, so that the through hole is torn or the interface between the mask film and the release film is It can prevent being pushed. Therefore, not only the loss of raw materials is minimized, but also the process can be performed continuously, thereby providing excellent process efficiency and low manufacturing cost.

1 is a view showing an embodiment of a method of manufacturing a polarizing plate according to the present invention.
2 is a flowchart illustrating a method of manufacturing a polarizing plate according to the present invention.
3 is a photograph of the pressure-sensitive adhesive protruding from the through hole portion of the peeled mask film.
4 is a photograph of a mask film in which a through hole portion is torn.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided in order to more completely explain the present invention to those having average knowledge in the art.

It is difficult to directly measure the angle between the films in the roll to roll process of the film, and the angle between the films varies depending on the size or thickness of the roll. Therefore, it is difficult to control the peeling condition of the film based on the angle between the films in the roll-to-roll process. On the other hand, in the method of manufacturing a polarizing plate of the present invention, the roll-to-roll process conditions can be easily controlled based on the angle between the rotation centers of the roll, thereby effectively peeling the film.

1 shows an embodiment of a method for manufacturing a polarizing plate of the present invention. 2 is a schematic flowchart of a method of manufacturing a polarizing plate according to the present invention. Hereinafter, the present invention will be described in more detail with reference to FIGS. 1 and 2. However, the matters described in the following drawings are only one embodiment of the present invention, and the present invention is not limited to the matters described in these drawings.

The manufacturing method of the polarizer of the present invention, as shown in FIG. 1, the release film and the release film while passing the laminate (A) in which the release film and the mask film having the through hole are stacked toward the second mask film guide roll (M2). It is a method comprising the step of separating the mask film. At this time, the laminate (A) is sequentially transferred to the second mask film guide roll (M2), separated into a release film and a mask film, and the separated mask film is toward the first mask film guide roll (M1), and separated The film is transferred to the release film roll (R1) side. The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 The angle (C) formed by the line connecting the center of rotation of) is 15° to 140°.

Meanwhile, the method of manufacturing a polarizing plate according to an exemplary embodiment of the present specification may further include attaching a polarizer, decoloring, washing, and/or removing the mask film, if necessary.

The term "rotation center of a roll" in the present specification refers to a point located at the center of the vertical section of the roll with respect to the rotation axis of the roll used in the process. Preferably, the cross section of the roll perpendicular to the axis of rotation of the roll is a circle and refers to the center of the circle.

The term "guide roll" in the present specification refers to a roll for guiding or rotating the transport/travel direction of a mask film, an optical film, or a polarizer.

In the present specification, "feature" may mean "lamination".

In the present specification, "run" may mean "transfer".

The present inventors, unlike physical removal methods such as punching and cutting, when forming a polarization canceling region locally by selectively contacting a decolorizing solution to a partial region of a polyvinyl alcohol-based polarizer dyed with iodine and/or a dichroic dye. It was found that no perforation occurs, and by first laminating the protective film on one side of the polarizer and then performing the decolorization process, the swelling phenomenon of the polarizer is suppressed, thereby minimizing fine wrinkles in the polarization canceling region.

In general, when the decolorization solution is directly contacted with a polyvinyl alcohol-based polarizer on which the protective film is not laminated, swelling of the polarizer occurs due to moisture, which causes wrinkles in the polarization resolution area and the surrounding area. Can occur. In this case, the surface roughness of the polarization canceling region increases and the haze increases, and as a result, it is difficult to sufficiently secure the appearance of the polarizing plate and the visibility of the camera positioned in the polarization canceling region. Thus, when the protective film is laminated on one side of the polarizer before contacting the decolorization solution as in the manufacturing method of the polarizing plate according to the exemplary embodiment of the present specification, since the protective film and the polarizer are adhered to each other, swelling and wrinkles are suppressed. I can make it.

In addition, the present inventors use a decolorization solution having a low surface tension, provide a mask layer including one or more through holes before contacting the polarizer with the decolorization solution, and then perform the step of forming a polarization elimination region, thereby making the continuous process easy and poor. It was found that the inhibitory effect of occurrence can be effectively improved.

In addition, the present inventors have found that by performing the step of attaching and peeling a release film during the process of manufacturing a mask layer including a through hole and attaching it to a polarizer, it is possible to protect the mask film and prevent tearing of the through hole. I put it out.

Hereinafter, each step of the manufacturing method according to an exemplary embodiment of the present specification will be described in more detail.

The polarizer may be manufactured through a method of manufacturing a polyvinyl alcohol-based (PVA) polarizer well known in the art, or may be used by purchasing a commercially available polyvinyl alcohol-based polarizer.

The step of providing the polyvinyl alcohol-based polarizer is, for example, but not limited thereto, for example, a dyeing step of dyeing a polyvinyl alcohol-based polymer film with iodine and/or a dichroic dye, It may be performed through a crosslinking step of crosslinking the polyvinyl alcohol-based film and a dye, and a stretching step of stretching the polyvinyl alcohol-based film.

First, the dyeing step is for dyeing iodine molecules and/or dichroic dye to a polyvinyl alcohol-based film, and iodine molecules and/or dichroic dye molecules absorb light vibrating in the stretching direction of the polarizer, and in the vertical direction By passing the light vibrating in the direction, it is possible to obtain polarized light having a specific vibration direction. In this case, the dyeing may be performed by impregnating a polyvinyl alcohol-based film into a treatment bath containing an iodine solution and/or a solution containing a dichroic dye, for example.

In this case, water is generally used as the solvent used in the solution in the dyeing step, but an appropriate amount of an organic solvent compatible with water may be added. Meanwhile, iodine and/or dichroic dye may be used in an amount of 0.06 parts by weight to 0.25 parts by weight based on 100 parts by weight of the solvent. When the dichroic material such as iodine is within the above range, the transmittance of the polarizer manufactured after stretching may satisfy the range of 40.0% to 47.0%.

On the other hand, when iodine is used as the dichroic material, it is preferable to further contain an auxiliary agent such as an iodide compound to improve dyeing efficiency, and the auxiliary agent is in a ratio of 0.3 to 2.5 parts by weight based on 100 parts by weight of the solvent. Can be used. At this time, the reason for the addition of the auxiliary agent such as the iodide compound is to increase the solubility of iodine in water because iodine has low solubility in water. On the other hand, the mixing ratio of the iodine and the iodide compound is preferably 1:5 to 1:10 by weight.

Specific examples of the iodide compound that may be added include potassium iodide, lithium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, or a mixture thereof. , But is not limited thereto.

On the other hand, the temperature of the treatment bath is preferably maintained at about 25 ℃ to 40 ℃. If the temperature of the treatment bath is less than 25°C, dyeing efficiency may decrease, and if the temperature of the treatment bath exceeds 40°C, iodine sublimates a lot and the amount of iodine used may increase.

At this time, the time to immerse the polyvinyl alcohol-based film in the treatment bath is preferably about 30 seconds to 120 seconds. If the immersion time is less than 30 seconds, dyeing may not be uniformly performed on the polyvinyl alcohol-based film, and if it exceeds 120 seconds, dyeing is saturated and there is no need for further immersion.

On the other hand, the crosslinking step is to allow iodine and/or dichroic dye to be adsorbed on the polyvinyl alcohol polymer matrix, and an immersion method performed by immersing a polyvinyl alcohol-based film in a crosslinking bath containing an aqueous boric acid solution, etc. is generally used. However, the present invention is not limited thereto, and may be carried out by a coating method or spraying method of applying or spraying a solution containing a crosslinking agent on a polyvinyl alcohol-based film.

At this time, the solvent used in the solution of the crosslinking bath is generally water, but an appropriate amount of an organic solvent compatible with water may be added, and the crosslinking agent is 0.5 parts by weight to 5.0 parts by weight based on 100 parts by weight of the solvent. It can be added in part. At this time, when the crosslinking agent is contained in an amount of less than 0.5 parts by weight, the strength of the polyvinyl alcohol-based film in water may decrease due to insufficient cross-linking in the polyvinyl alcohol-based film, and when it exceeds 5.0 parts by weight, excessive cross-linking is formed. As a result, the stretchability of the polyvinyl alcohol-based film can be reduced. Specific examples of the crosslinking agent include boron compounds such as boric acid and borax, glyoxal, glutaraldehyde, and the like, and these may be used alone or in combination. However, it is not limited thereto.

On the other hand, the temperature of the crosslinking bath varies depending on the amount of the crosslinking agent and the draw ratio, and is not limited thereto, but is generally preferably 45°C to 60°C. In general, when the amount of crosslinking agent increases, the temperature of the crosslinking bath is adjusted under high temperature conditions to improve the mobility of the polyvinyl alcohol-based film chain. Adjust the temperature. However, since the method of manufacturing a polarizing plate according to an exemplary embodiment of the present specification is a process in which 5 times or more stretching is performed, the temperature of the crosslinking bath must be maintained at 45° C. or higher in order to improve the stretchability of the polyvinyl alcohol-based film. On the other hand, the time for immersing the polyvinyl alcohol-based film in the crosslinking bath is preferably about 30 seconds to 120 seconds. If the immersion time is less than 30 seconds, crosslinking may not be uniformly performed on the polyvinyl alcohol-based film, and if it exceeds 120 seconds, the crosslinking is saturated and there is no need for further immersion.

On the other hand, stretching in the stretching step is to orient the polymer chains of the polyvinyl alcohol-based film in a certain direction. The stretching method can be divided into a wet stretching method and a dry stretching method, and the dry stretching method is again inter-roll stretching. A method, a heating roll stretching method, a compression stretching method, a tenter stretching method, and the like, and the wet stretching method is classified into a tenter stretching method, an inter-roll stretching method, and the like.

At this time, the stretching step is preferably stretching the polyvinyl alcohol-based film at a draw ratio of 4 to 10 times. Because, in order to impart polarization performance to the polyvinyl alcohol-based film, the polymer chains of the polyvinyl alcohol-based film must be oriented. At a draw ratio of less than 4 times, the chain may not be sufficiently oriented. This is because the chains of vinyl alcohol-based films can be cut.

At this time, the stretching is preferably stretched at a stretching temperature of 45 ℃ to 60 ℃. The stretching temperature may vary depending on the content of the crosslinking agent. At a temperature of less than 45° C., the fluidity of the polyvinyl alcohol-based film chain may decrease, resulting in a decrease in stretching efficiency. When it exceeds 60° C., the polyvinyl alcohol-based film This is because the strength may be weakened due to softening. Meanwhile, the stretching step may be performed simultaneously or separately with the dyeing step or crosslinking step.

Meanwhile, the stretching may be performed by the polyvinyl alcohol-based film alone, or by laminating the base film on the polyvinyl alcohol-based film, and then stretching the polyvinyl alcohol-based film and the base film together. In the case of stretching a thin polyvinyl alcohol-based film (for example, a PVA film of 60 μm or less), the latter two are used to prevent the polyvinyl alcohol-based film from breaking during the stretching process. It can be used to manufacture a thin PVA polarizer.

In this case, as the base film, polymer films having a maximum draw ratio of 5 times or more under a temperature condition of 20°C to 85°C may be used, for example, a high-density polyethylene film, a polyurethane film, a polypropylene film, a polyolefin film, Ester-based film, low-density polyethylene film, high-density polyethylene and low-density polyethylene coextrusion film, copolymer resin film containing ethylene vinyl acetate in high-density polyethylene, acrylic film, polyethylene terephthalate film, polyvinyl alcohol-based film, cellulose-based film, etc. Can be used. Meanwhile, the maximum draw ratio means a draw ratio just before fracture occurs.

In addition, the method of laminating the base film and the polyvinyl alcohol-based film is not particularly limited. For example, the base film and the polyvinyl alcohol-based film may be laminated through an adhesive or pressure-sensitive adhesive, or may be laminated by placing a polyvinyl alcohol-based film on the base film without a separate medium. In addition, it may be performed by a method of coextruding a resin forming a base film and a resin forming a polyvinyl alcohol-based film, or by coating a polyvinyl alcohol-based resin on the base film.

Meanwhile, the base film may be removed by separating from the polarizer after the stretching is completed, but may proceed to the next step without removing it. In this case, the base film may be used as a polarizer protective film to be described later.

Next, when a polarizer is prepared through the method, a step of providing a protective film on one surface of the polarizer may be performed.

The step of providing the protective film may be performed by a method of providing a polarizer in the stretching step or a method of providing a protective film on a surface opposite to a surface of the polarizer facing the mask film.

At this time, the protective film is a film for protecting a polarizer having a very thin thickness, and refers to a transparent film attached to one side of the polarizer, and a film having excellent mechanical strength, thermal stability, moisture shielding property, and isotropic property may be used. For example, acetate-based, polyester-based, polyethersulfone-based, polycarbonate-based, polyamide-based, polyimide-based, polyolefin-based, cycloolefin-based, polyurethane-based and acrylic resin films such as triacetylcellulose (TAC), etc. Can be used, but is not limited thereto.

In addition, the protective film may be an isotropic film, may be an anisotropic film to which a compensation function such as a retardation is given, and may be composed of one sheet or formed by bonding two or more sheets. In addition, the protective film may be an unstretched, uniaxial or biaxially stretched film, and the thickness of the protective film may be generally 1 μm to 500 μm, preferably 1 μm to 300 μm.

In this case, the protective film may preferably have an adhesive strength of 1N/2cm or more to a polyalcohol-based polarizer, and more preferably 2N/2cm or more. Specifically, the adhesion refers to adhesion measured by 90 degree peeling force using a texture analyzer after attaching the protective film to a polyvinyl alcohol polarizer dyed with at least one of iodine and dichroic dye. When the adhesive strength satisfies the above range, swelling between the protective film and the polyvinyl alcohol-based polarizer can be suppressed, and the occurrence of curls and defects during the manufacturing process can be minimized.

On the other hand, the step of laminating the protective film on one surface of the polyvinyl alcohol-based polarizer is by bonding the protective film to the polarizer, and may be bonded using an adhesive. At this time, it may be carried out through a method of laminating films known in the art, and for example, water-based adhesives such as polyvinyl alcohol-based adhesives, thermosetting adhesives such as urethane-based adhesives, photo cation curable adhesives such as epoxy-based adhesives, It can be carried out using adhesives known in the art, such as photo-radical curable adhesives such as acrylic adhesives.

The protective film may be removed after the mask film is provided on the polarizer.

In an exemplary embodiment of the present invention, a step of removing the protective film after the decolorization step to be described later may be further included.

On the other hand, it is possible to perform the step of providing a mask film having a through hole. One or more through-holes.

In an exemplary embodiment of the present invention, the number of through holes is two or more, and are disposed at predetermined intervals in the length direction of the mask film.

In an exemplary embodiment of the present invention, the number of through holes is two or more, and are arranged at equal intervals in the length direction of the mask film.

In one embodiment of the present invention, the number of through holes is two or more, and are disposed at predetermined intervals in the width direction of the mask film.

In an exemplary embodiment of the present invention, the number of through holes is two or more, and are arranged at equal intervals in the width direction of the mask film.

In an exemplary embodiment of the present invention, the number of through holes is two or more, and are arranged at equal intervals in the length direction of the mask film and the width direction of the mask film. The distance in the length direction and the distance in the width direction are the same or different.

The spacing of the through holes may vary depending on the application of the device or product to be applied. For example, several through-holes are arranged at different intervals to form one unit, and the units may be arranged at equal intervals. In the mobile device, several through-holes are formed at positions corresponding to the camera part, the logo-shaped part, the sensor part, and/or the flash part, and the units may be arranged at equal intervals to form one unit.

In this case, as the mask film, an olefin-based film such as polyethylene (PolyEthylene, PE), polypropylene (PolyPropylene, PP), polyethylene terephthalate (PolyEthyleneTerephtalate, PET), etc.; Alternatively, a vinyl acetate-based film such as ethylene vinyl acetate (EVA) or polyvinyl acetate may be used, but is not limited thereto. Further, the thickness of the mask film is not limited thereto, but may be about 10 μm to 100 μm, preferably about 10 μm to 70 μm.

According to an exemplary embodiment of the present specification, the mask film is a polyethylene (PolyEthylene, PE) film, a polypropylene (PP) film, a polyethylene terephthalate (PET) film, and an ethylene vinyl acetate (EVA) film. Film or polyvinyl acetate (PolyVinyl Acetate) film.

The step of forming the through hole in the mask film is not particularly limited, and may be performed through film penetrating methods well known in the art, for example, die cutting, mold processing, knife processing, or laser processing. .

According to the exemplary embodiment of the present specification, the step of forming the through hole may be performed using laser processing or die cut.

The laser processing may be performed using laser processing apparatuses generally known in the art, and is not particularly limited. Laser processing conditions such as the type of laser device, output, laser pulse repetition rate, etc. may vary depending on the material or thickness of the film, the shape of the through hole, etc., and those skilled in the art may consider the above points and appropriate the laser processing conditions. You will be able to choose. For example, in the case of using a polyolefin film having a thickness of 30 µm to 100 µm as a mask film, a carbon dioxide (CO ₂ ) laser device having a center wavelength of about 9 µm to 11 µm or an ultraviolet ray having a center wavelength of about 300 nm to 400 nm ( A through hole may be formed using a UV) device or the like, and in this case, the maximum average power of the laser device may be about 0.1W to 30W, and the pulse repetition rate may be about 0kHz to 50kHz, but is not limited thereto.

On the other hand, the through hole may be formed to correspond to the shape of the region to be decolored, and the shape or formation position thereof is not particularly limited. For example, the through hole may be formed to correspond to the shape of the part at a position where a part such as a camera is mounted, may be formed in the shape of a product logo in the area where the product logo is printed, and the edge of the polarizer If you want to give a color to the polarizer may be formed in the form of a frame on the edge of the polarizer.

The step of forming the through hole may be performed before or after the step of attaching to the other surface of the polarizer. In other words, after forming the through hole in the mask film in advance, the mask film in which the through hole is formed may be attached to the polarizer, or the through hole may be formed after attaching the mask film to the polarizer.

Attaching the mask film to the polarizer may be performed by laminating films well known in the art, for example, attaching the mask film and the polarizing member through an adhesive layer, wherein the adhesive layer Silver may be formed by applying an adhesive such as an acrylic adhesive, a silicone adhesive, an epoxy adhesive, a rubber adhesive, or the like on a mask film or a polarizing member, but is not limited thereto. For example, when using self-adhesive films (eg, EVA film, PVAC film, PP film, etc.) as a mask film, the mask film may be directly attached to the other surface of the polarizer without forming an adhesive layer.

According to an exemplary embodiment of the present specification, a release film may be provided on one surface of the mask film.

According to an exemplary embodiment of the present specification, an adhesive layer and a release film may be provided on one surface of the mask film.

According to an exemplary embodiment of the present specification, a pressure-sensitive adhesive layer and a release film may be provided on a surface of the mask film facing the polarizer.

Since the release film serves to prevent deformation of the outer shape such as shrinkage of the mask film in the step of forming the through hole, the step of providing the release film may be performed before the step of forming the through hole.

Examples of the release film include olefin-based films such as polyethylene (PolyEthylene, PE), polypropylene (PP), polyethylene terephthalate (PET), and the like; Alternatively, a vinyl acetate-based film such as ethylene vinyl acetate (EVA) or polyvinyl acetate may be used, but is not limited thereto.

The step of providing the release film on the surface of the mask film facing the polarizer is to adhere the release film to the protective film, which may be bonded using an adhesive. The pressure-sensitive adhesive may be a pressure sensitive adhesive (PSA). In addition, according to an exemplary embodiment of the present specification, the release film may be a release film itself has adhesive strength. That is, the protective film and the release film are provided on one side of the polarizer as if they were one film.

According to an exemplary embodiment of the present specification, comprising: providing a release film on one surface of the mask film; And integrally penetrating the mask film and the release film to form a laminate (A) having the through hole. In this case, the release film is provided on a surface opposite to a surface of the pressure-sensitive adhesive that faces the mask film.

According to an exemplary embodiment of the present specification, the laminate (A) further includes an adhesive layer between the release film and the mask film.

According to an exemplary embodiment of the present specification, it includes removing the release film before the mask film is attached to the polarizer. The step of removing the release film may be performed by a method of peeling the release film from the protective film. More specifically, the step of removing the release film may be performed by a method of peeling the release film from the protective film using a release roll or the like.

According to an exemplary embodiment of the present specification, the stack (A) of the release film and the mask film is transferred to the second mask film guide roll (M2), and separated into the release film and the mask film. Thereafter, the separated mask film is transferred to the first mask film guide roll M1 side, and the separated release film is transferred to the release film roll R1 side.

The second mask film guide roll M2 separates the stack A to rotate the driving direction of the mask film and the release film, and the first mask film guide roll M1 determines the driving direction of the separated mask film. Rotate. The release film roll is wound up the separated release film.

According to an exemplary embodiment of the present specification, sizes of the release film roll R1 and the first and second mask film guide rolls M1 and M2 are the same or different from each other.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of R1, M1 and M2 are the same or different from each other.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and M2 are the same or different from each other.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and M2 are the same.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and M2 are different from each other.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and R1 are the same or different from each other.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and R1 are the same.

According to an exemplary embodiment of the present specification, the rotation directions of the rolls of M1 and R1 are different from each other.

The material of the roll is not limited to SUS, rubber, etc., and the diameter of the roll has a size of 8cm to 2500cm. In general, the tension (tension) control of the rolled film is performed so that the speed of the release film roll is adjusted according to the increase in the amount of the release film. Although not limited thereto, it is preferable to perform the tension at 5 to 80kgf.

According to an exemplary embodiment of the present specification, the diameter of the release film roll (R1) is 8cm to 2500cm.

According to an exemplary embodiment of the present specification, the tension of the release film wound in the release film (R1) is 5 to 80kgf.

According to an exemplary embodiment of the present specification, a line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, and the rotation center of the release film roll R1 The angle C formed by the line connecting the rotation center of the first mask film guide roll M1 is 15° to 140°. At this time, the angle C is the rotation center of the release film roll R1 and the first mask film guide from a line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2. It refers to the angle measured in the rotation direction of the first mask film guide roll M1 up to the line connecting the rotation center of the roll M1. Preferably, the angle C is 30 ° to 120 °, 50 ° to 80 °. If the angle C is less than 15°, the interface between the pressure-sensitive adhesive and the release film is pushed, making a continuous process difficult, and the shape of the mask is not clear during decolorization because the pressure-sensitive adhesive is pushed out of the through hole. If the angle C is more than 140°, the mask film The through hole is torn, making it difficult to expect the role of the mask film. When the interface between the films is pushed, it is difficult for the decolorizing liquid to enter between the polarizer and the mask film and decolorize only the portion corresponding to the through hole.

In the present invention, by controlling the angle between rolls in a roll-to-roll process, it is possible to quickly respond to defects occurring during the process, and to minimize loss of raw materials.

Next, the mask film having the through hole passes through the first mask film guide roll M1 and is transferred to the first bonding roll L1 side.

In addition, the polarizer passes through the polarizer guide roll P1 and is transferred to the second bonding roll L2.

The first mask film guide roll M1 guides the driving direction of the mask film, and the polarizer guide roll P1 guides the driving direction of the polarizer.

The sizes of the rolls of M1, P1, L1 and L2 are the same or different from each other.

The mask film and the polarizer are stacked while passing the transferred mask film and the transferred polarizer between the first bonding roll L1 and the second bonding roll L2 contacting each other. The advantage of reducing the rate of defects during the Roll to Roll process because the areas that do not want to be decolored are not covered with the mask layer, and the process speed is not limited because the polyvinyl alcohol polarizer and mask layer are stacked. There is this.

In addition, the manufacturing method of the present invention may further include the step of decolorizing the mask film and the polarizer by contacting a decolorizing solution if necessary.

Meanwhile, the decolorization solution essentially contains a decolorizing agent and a solvent capable of decolorizing iodine and/or a dichroic dye. The decolorizing agent is not particularly limited as long as it can decolorize iodine and/or dichroic dye dyed on the polarizer.

At this time, the decolorization solution is preferably a strong base having a pH of 11 to 14, and more specifically, sodium hydroxide (NaOH), sodium sulfate (NaSH), sodium azitide (NaN ₃ ), potassium hydroxide (KOH) , Potassium sulfate (KSH) and potassium thiosulfate (KS ₂ O ₃ ) It may be to include one or more bleaching agents selected from the group consisting of. The viscosity of the bleaching solution may be about 1 cP to 2000 cP, and the bleaching solution may contain 1% to 30% by weight of a bleaching agent based on the total weight. In addition, the decolorization solution may contain 1% to 50% by weight of an alcohol-based solvent based on the total weight, and may contain 0.01% to 0.5% by weight of a surfactant based on the total weight.

It is preferable to use water such as distilled water or the like as the solvent. In addition, the solvent may be used by additionally mixing an alcohol solvent. Although not limited thereto, for example, methanol, ethanol, butanol, isopropyl alcohol, and the like may be mixed and used.

On the other hand, the content of the bleaching agent in the bleaching solution may vary depending on the contact time in the bleaching process, but preferably about 1% to 30% by weight, more preferably 5% by weight to the total weight of the bleaching solution. It is preferable to include about 15% by weight. When the content of the bleaching agent is less than 1% by weight, decolorization does not occur, or it takes tens of minutes or more to decolorize, making it difficult to apply practically, and when it exceeds 30% by weight, the decolorization solution does not easily diffuse into the polarizer. Therefore, the increase in the bleaching efficiency is insignificant, and the economic feasibility is poor.

In addition, according to the exemplary embodiment of the present specification, the pH of the bleaching solution may be 11 to 14. Preferably, it may be 13 to 14. The bleaching agent is a strong basic compound and must have a strong basicity enough to destroy boric acid forming a crosslinking between polyvinyl alcohols, and when the pH satisfies the above range, bleaching may occur well. For example, sodium thiosulfate (pH 7), as a solution that decomposes (decolors) iodine and makes it transparent (ioding clock reaction), may cause discoloration in a general iodine compound aqueous solution, but even if contacted for a long time in an actual polarizer (PVA). (10 hours) No discoloration occurs. In other words, this suggests that the crosslinking of boric acid with a strong base must be broken before decomposing iodine.

According to the exemplary embodiment of the present specification, the viscosity of the bleaching solution may be 1 cP to 2000 cP. More specifically, according to the exemplary embodiment of the present specification, the viscosity of the bleaching solution may be 5 cP to 2000 cP.

An exemplary embodiment of the present specification also provides a bleaching solution having a surface tension of 50 mN/m or less.

According to an exemplary embodiment of the present specification, the decolorization solution may include 1% to 50% by weight of an alcohol-based solvent based on the total weight of the decolorization solution.

According to the exemplary embodiment of the present specification, the bleaching solution may include 0.01% to 0.5% by weight of a surfactant based on the total weight of the bleaching solution.

When the content range of the alcohol-based solvent and/or surfactant is within the above range, there is an advantage in that a bleaching solution having a surface tension of 50 mN/m or less can be obtained.

On the other hand, the decolorization step is preferably performed for 1 second to 60 seconds in a decolorization solution of 10 ℃ to 70 ℃. When the temperature and the immersion time of the decolorization solution are out of the above numerical range, problems such as swelling and separation of the polarizer may occur due to the decolorization solution, resulting in a bend in the polarizer or decolorization to an undesired area.

Meanwhile, in the present specification, in the step of decolorizing by contacting the decolorizing solution, only the portion in which the through hole is formed by being immersed in the decolorizing solution is subjected to a decolorization process. Specifically, after forming a mask layer on one surface of the polarizer, the polarizer provided with the protective film may be immersed in a decolorization solution. In the case of using the immersion process, unlike the coating process in which it is difficult to properly adjust the treatment time according to the situation due to a short treatment time, there is an advantage that the treatment time can be appropriately adjusted when the temperature or concentration is changed. That is, when performing the decolorization process using the immersion process, there is an advantage that the treatment time can be adjusted if necessary.

When a polarizer provided with a mask film including a through hole is immersed in the decolorization solution as described above, the decolorization solution comes into contact with the polarizer through the through hole, and as a result, only the portion corresponding to the through hole area is partially decolored. .

On the other hand, the mechanism by which polarization is eliminated through the decolorization step of the present specification will be described in detail. It is known that a composite of polyvinyl alcohol dyed with iodine and/or a dichroic dye can absorb light in the visible range of 400 nm to 800 nm. At this time, when the decolorization solution is brought into contact with the polarizer, iodine and/or a dichroic dye that absorbs light in the visible wavelength band present in the polarizer is decomposed, thereby decolorizing the polarizer to increase transmittance and lower the degree of polarization.

For example, when an aqueous solution containing potassium hydroxide (KOH), which is a decolorizing agent, is brought into contact with a partial region of a polyvinyl alcohol-based polarizer dyed with iodine, iodine is decomposed in a series of processes as shown in the following Chemical Formulas 1 and 2. . On the other hand, in the case of crosslinking with boric acid when preparing a polyvinyl alcohol polarizer with iodine dyed, potassium hydroxide directly decomposes boric acid as described in Formula 3 below, thereby removing the crosslinking effect through hydrogen bonding between polyvinyl alcohol and boric acid. Is done.

[Formula 1]

[Formula 2]

[Formula 3]

That is, by absorbing visible light ^{_{I 5 - (620nm), I}} 3 - (340nm), I 2 - decomposing the iodine and / or iodine ion complexes, such as (460nm), I ^- (300nm or less), or As salt is formed, most of the light in the visible region is transmitted. As a result, the polarization function is eliminated in a region of about 400 nm to 800 nm, which is a visible light region of the polarizer, so that overall transmittance is increased and the polarizer becomes transparent. In other words, the polarization function can be eliminated by decomposing the arrayed iodine complex that absorbs visible light into a single molecule that does not absorb visible light in order to make polarization in the polarizer.

In addition, the manufacturing method of the present invention may further include washing using an alcohol or acid solution after the step of decolorizing the mask film and the polarizer, if necessary.

When the decolorization process as described above is completed, if necessary, a step of washing the decolorization solution (not shown) may be performed. This is because when the decolorization solution remains in the polarizing member, polarizer decolorization may occur in an unwanted area due to the decolorization solution remaining in a subsequent process.

In this case, the washing may be performed by immersing the polarizing member in alcohol or acidic aqueous solution, or pure water, or applying alcohol or acidic aqueous solution or pure water on the polarizing member. In particular, in the case of the alcohol, it is easy to dry and can be easily removed, and since it does not affect transmittance or polarization degree to a polarizer other than a polarization canceling region, it may be suitably used. At this time, as the alcohol, for example, ethanol, methanol, propanol, butanol, isopropyl alcohol, or a mixture thereof may be used. In addition, in the case of the acidic solution, the residual decolorizing agent, which is mainly basic, is removed by neutralizing the acid solution and the acidic solution includes, for example, an aqueous acetic acid solution, an aqueous adipic acid solution, an aqueous boric acid solution, an aqueous phosphoric acid solution, An aqueous solution, an aqueous sulfuric acid solution, an aqueous nitric acid solution, or a mixed solution thereof may be used, but is not limited thereto.

In the washing step, the polarizer is immersed in alcohol for 1 second to 180 seconds, more preferably for 3 seconds to 30 seconds, or in contact with the decolorizing solution, and using a dispenser or ink jet, the alcohol or acid A method of applying a solution can be used.

According to an exemplary embodiment of the present specification, by washing with an alcohol or acid solution after using a bleaching agent, the iodine compound and salt formed by the bleaching agent are washed out as described above, and the content of iodine and iodine ion complexes in the through hole region Is minimized. Accordingly, the absorption of light of residual iodine and iodine ion complexes in the through-hole region is reduced, resulting in a more transparent effect.

In addition, the manufacturing method of the present invention may further include removing the mask film from the decolored polarizer, if necessary.

The step of removing the mask film may be performed by a method of peeling the mask film from the polarizer. More specifically, the step of removing the mask film may be performed by a method of peeling the mask film from the polarizer using a peeling roll or the like.

In addition, the manufacturing method of the present invention may further include forming an optical layer on at least one surface of the polarizer after the decolorization step, if necessary, although not essential. At this time, the optical layer may be a polymer film layer such as a protective film or a retardation film, may be a functional film layer such as a brightness enhancing film, a hard coating layer, an antireflection layer, an adhesive layer, a functional layer such as an adhesive layer, or a combination thereof May be.

In an exemplary embodiment of the present invention, a polarizing plate is formed by laminating a protective film on one or both sides of the decolored polarizer.

In another aspect, the present invention provides an apparatus for manufacturing a polarizing plate that performs the above process.

The apparatus for manufacturing a polarizing plate according to an exemplary embodiment of the present specification includes a second mask film guide roll (M2) for separating a laminate (A) in which a release film and a mask film having a through hole are stacked into the release film and the mask film. ;

A first mask film guide roll (M1) rotating the direction of the separated mask film; And

Including a release film roll (R1) winding the separated release film,

The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 The angle (C) formed by the line connecting the center of rotation of) is 15° to 140°. Preferably, the angle C is between 30° and 120°.

The apparatus for manufacturing the polarizing plate may include components known in the art except for the first mask film guide roll (M1), the second mask film guide roll (M2), the release film roll (R1), and the angle C. have. For example, it may include a first bonding roll (L1), a second bonding roll (L2), or/and a polarizer guide roll (P1).

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited thereby.

[Production Example] Preparation of mask film and release film

A laminate of a release film and a mask film was prepared by coating a pressure-sensitive adhesive on PET (mask film) having a thickness of 30 μm and laminating 15 μm PET (release film) on the top. After that, a hole having a diameter of 3 mm was formed at intervals of 30 cm with an output of 10 W and a pulse repetition rate of 20 kHz using a CO ₂ laser.

[Example]

<Examples 1 to 4 and Comparative Examples 1 to 5>

The release film and the mask film were separated from the laminate prepared in the above Preparation Example by adjusting the angle between the bonding roll and the guide roll to the angle of C shown in Table 1 below.

[evaluation]

<Evaluation of release film/adhesive interface slippage>

If the pressure-sensitive adhesive slipped into the through hole, it was evaluated as Y, and if not, it was evaluated as N.

<Evaluation of tearing through mask film>

Out of 100 through holes, if 10 or more torn were evaluated as O, 5 to 10 were evaluated as △, and 4 or less were evaluated as X.

The evaluation results are shown in Table 1 below.

C(°) Release film/adhesive interface push Mask film through hole tear Example 1 20 N X Example 2 50 N X Example 3 80 N X Example 4 130 N X Comparative Example 1 5 Y X Comparative Example 2 10 Y X Comparative Example 3 150 N △ Comparative Example 4 180 N O Comparative Example 5 200 N O

When the release film and the mask film are peeled off by the method of Examples 1 to 4, a continuous process is possible without the release film and the adhesive interface being pushed. On the other hand, in Comparative Examples 1 and 2, the angle C was less than 15°, and the interface between the release film and the adhesive was pushed, making it difficult to perform a continuous process. This is not clear. In FIG. 3, the adhesive protruding from the through hole portion of the peeled mask film of Comparative Example 1 can be seen.

In the case of Examples 1 to 4, the through holes of the peeled mask film were not torn, whereas in Comparative Examples 3 to 5, the angle C was greater than 140°, and the through holes of the peeled mask film were torn. 4, it can be seen that the through hole of Comparative Example 4 is torn.

Therefore, the manufacturing of the polarizing plate by the method of the present invention can minimize the loss of raw materials and is excellent in process efficiency.

Through the above, although the preferred embodiment of the present specification has been described, the present invention is not limited thereto, and it is possible to implement various modifications within the scope of the claims and the detailed description of the invention, and this also falls within the scope of the invention. Belongs.

M1: first mask film guide roll
M2: second mask film guide roll
P1: Polarizer guide roll
L1: 1st bonding roll
L2: second bonding roll
C: The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, and the rotation center of the release film roll R1 and the first mask film guide roll M1 The angle formed by the line connecting the center of rotation
10: polarizer/protective film
20: mask film/adhesive
30: mask film/adhesive/polarizer/protective film
40: mask film/adhesive/release film
50: release film

Claims (16)

(S1) preparing a laminate (A) in which a release film and a mask film having a through hole are stacked;
(S2) transferring the laminate (A) to the second mask film guide roll (M2) to separate the release film and the mask film;
(S3) transferring the separated mask film to the first mask film guide roll (M1); And
(S4) Including the step of transferring the separated release film to the release film roll (R1) side,
The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 A method of manufacturing a polarizing plate having an angle (C) of 15° to 140° formed by a line connecting the center of rotation of ). The method according to claim 1,
The angle C is a method of manufacturing a polarizing plate of 30 ° to 120 °. The method according to claim 1,
The laminate (A) further includes a pressure-sensitive adhesive layer between the release film and the mask film having a through hole, and the step S2 is to separate the release film and the mask film to which the pressure-sensitive adhesive layer is attached to prepare a polarizing plate Way. The method according to claim 1,
A method of manufacturing a polarizing plate further comprising attaching the separated mask film and a polarizer. The method according to claim 1,
The S1 step is a method of manufacturing a polarizing plate to form a laminate (A) by integrally penetrating the release film and the mask film. The method of claim 5,
The method of manufacturing a polarizing plate to form a through hole using a laser or die cut in the step S1. The method of claim 4,
A method of manufacturing a polarizing plate further comprising the step of decolorizing the mask film and the polarizer by contacting a decolorizing solution. The method of claim 7,
After the decolorizing step, a method of manufacturing a polarizing plate further comprising washing with an alcohol or acid solution. The method of claim 7,
The method of manufacturing a polarizing plate further comprising removing the mask film after the decolorizing step. The method of claim 7,
The bleaching solution is a method of manufacturing a polarizing plate that has a pH of 11 to 14. The method of claim 7,
The bleaching solution is a group consisting of sodium hydroxide (NaOH), sodium sulfate (NaSH), sodium azite (NaN ₃ ), potassium hydroxide (KOH), potassium sulfate (KSH), and potassium thiosulfate (KS ₂ O ₃ ) A method of manufacturing a polarizing plate comprising at least one bleaching agent selected from. The method of claim 7,
The method of manufacturing a polarizing plate that the viscosity of the bleaching solution is 1 cP to 2000 cP. The method of claim 7,
The bleaching solution is a method of manufacturing a polarizing plate containing 1% to 30% by weight of a bleaching agent based on the total weight. The method according to claim 1,
The mask film having the through-hole is a polyethylene (PolyEthylene, PE) film, a polypropylene (PP) film, a polyethylene terephthalate (PET) film, an ethylene vinyl acetate (EVA) film, or a polyvinyl acetate film. (PolyVinyl Acetate) A method of manufacturing a polarizing plate, characterized in that the film. A second mask film guide roll (M2) separating the stacked body (A) in which a release film and a mask film having a through hole are stacked into the release film and the mask film;
A first mask film guide roll (M1) rotating the direction of the separated mask film; And
Including a release film roll (R1) winding the separated release film,
The line connecting the rotation center of the first mask film guide roll M1 and the rotation center of the second mask film guide roll M2, the rotation center of the release film roll R1, and the first mask film guide roll M1 A polarizing plate manufacturing device with an angle (C) of 15° to 140° formed by a line connecting the center of rotation of ). The method of claim 15,
The angle C is an apparatus for manufacturing a polarizing plate of 30 ° to 120 °.

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