KR20130078073A - Multilayer reflective polizer having bead coating layer - Google Patents

Abstract

PURPOSE: A multi layer reflective polarizer including a bead coating layer is provided to improve scratch resistance while enhancing an optical property including brightness. CONSTITUTION: Skin layers (189,190) are integrally formed at both sides of a core layer (180). Bead coating layers (191,192) are formed at one side of the skin layer. The core layer is separated into two groups. The group A alternatively laminates first layers (181, 183) which are first element and second layers (182, 184) which are second element. The first layer and the second layer are defined as one repetition unit (R1) and the group A can include at least 25 repetition units. The group B alternatively laminates first layers (185,187) and second layers (182,184). The first layer and the second layer are defined as one repetition unit (R2) and the group B can include at least 25 repetition units.

Description

 Multilayer reflective polizer having bead coating layer

The present invention relates to a reflective polarizer including a bead coating layer, and more particularly, to include a bead coating layer on at least one surface of the multilayer reflective polarizer to include an optical coating and a bead coating layer capable of improving scratch resistance. It is to provide a reflective polarizer.

Flat panel display technology is mainly composed of liquid crystal display (LCD), projection display, and plasma display (PDP), which have already secured a market in the TV field. In addition, field emission display (FED) and electroluminescence display (ELD) And it is expected to occupy the field according to each characteristic. Liquid crystal displays are currently being used in a wide range of applications such as notebook computers, personal computer monitors, liquid crystal TVs, automobiles, and aircrafts, accounting for 80% of the flat panel market, and booming demand for LCDs worldwide.

Conventional liquid crystal displays place a liquid crystal and an electrode matrix between a pair of light absorbing optical films. In liquid crystal displays, the liquid crystal portion has an optical state that changes accordingly by moving the liquid crystal portion by an electric field generated by applying a voltage to the two electrodes. This process displays an image by using a polarized light in a specific direction as a 'pixel' containing information. For this reason, liquid crystal displays include a front optical film and a rear optical film that induce polarization.

  The optical film used in such a liquid crystal display does not necessarily have a high utilization efficiency of light emitted from the backlight. This is because 50% or more of the light emitted from the backlight is absorbed by the back side optical film (absorption type polarizing film). Therefore, in order to improve the utilization efficiency of the backlight in the liquid crystal display, a reflection type polarizer is provided between the optical cavity and the liquid crystal assembly.

  1 is a view showing the optical principle of a conventional reflective polarizer. Specifically, the P polarized light from the optical cavity toward the liquid crystal assembly is transmitted through the reflective polarizer to the liquid crystal assembly. The S polarized light is reflected from the reflective polarizer into the optical cavity, Direction is reflected in a randomized state and is then transmitted to the reflective polarizer so that the S polarized light is converted into P polarized light that can pass through the polarizer of the liquid crystal assembly and is transmitted to the liquid crystal assembly after passing through the reflective polarizer.

The selective reflection of S-polarized light and the transmission of P-polarized light with respect to the incident light of the reflective polarizer are based on the refractive index of each optical layer in a state where an optical layer on a plate having anisotropic refractive index and an optical layer on a plate having an isotropic refractive index are laminated alternately. It is made by the optical thickness setting of each optical layer and the refractive index change of the optical layer according to the difference and the stretching process of the stacked optical layers.

  That is, the light incident on the reflective polarizer repeats the reflection of the S polarized light and the transmission of the P polarized light while passing through each optical layer, and finally, only the P polarized light of the incident polarized light is transmitted to the liquid crystal assembly. On the other hand, as described above, the reflected S polarized light is reflected in the polarization state of the diffused reflection plane of the optical cavity in a randomized state and then transmitted to the reflective polarizer. As a result, it is possible to reduce the waste of power with loss of light generated from the light source.

 However, the conventional reflective polarizer has an optical thickness and a refractive index between the optical layers that can be optimized for selective reflection and transmission of incident polarization by alternately stacking isotropic optical layers and anisotropic optical layers having different refractive indices. Since it is manufactured to have, there was a problem that the manufacturing process of the reflective polarizer is complicated. In particular, since each optical layer of the reflective polarizer has a flat plate structure, the P polarized light and the S polarized light must be separated in accordance with a wide incident angle range of incident polarized light, so that the number of layers of the optical layer is excessively increased and the production cost exponentially There was an increasing problem. Further, there is a problem that optical performance is deteriorated due to optical loss due to the structure in which the number of layers of the optical layer is excessively formed.

2 is a cross-sectional view of a conventional multilayer reflective polarizer (DBEF). Specifically, in the multilayer reflective polarizer, the skin layers 9 and 10 are formed on both sides of the core layer 8. The core layer 8 is divided into four groups (1, 2, 3, 4), in which each of the isotropic layers and the anisotropic layers are alternately stacked to form approximately 200 layers. Separate adhesive layers 5, 6, and 7 are formed between the four groups 1, 2, 3, and 4 forming the core layer 8. In addition, since each group has a very thin thickness of about 200 layers, these groups often contain a protective layer (PBL) since individual groups can be damaged if they are individually pneumatically shipped. In this case, there is a problem that the thickness of the core layer becomes thick and the manufacturing cost rises. In addition, since the reflective polarizer included in the display panel is limited in the thickness of the core layer for slimming, if the adhesive layer is formed on the core layer and / or the skin layer, the core layer is reduced by the thickness thereof, There was no problem. Further, since the inside of the core layer and the core layer and the skin layer are bonded by the adhesive layer, there is a problem that when the external force is applied, the elapse of time elapses, or the storage place is poor, delamination occurs. In addition, not only the defect rate is excessively increased in the process of adhering the adhesive layer, but also the destructive interference to the light source occurs due to the formation of the adhesive layer.

Skin layers 9 and 10 are formed on both sides of the core layer 8 and separate adhesive layers 11 and 12 are formed between the core layer 8 and the skin layers 9 and 10 for bonding them. do. In case of integrating the conventional polycarbonate skin layer and PEN-coPEN by alternatingly laminated core layer through co-extrusion, peeling may occur due to incompatibility, and the crystallization degree is about 15%. There is a high risk of birefringence. Accordingly, in order to apply the polycarbonate sheet of the non-smelting process, an adhesive layer has to be formed. As a result, the yield decreases due to external foreign matters and process defects due to the addition of the adhesive layer process. Generally, in producing a polycarbonate-free sheet of the skin layer, birefringence occurs due to uneven shear pressure due to the winding process, It is necessary to control the molecular structure of the polymer and speed control of the extrusion line in order to compensate for the deterioration of productivity.

The method of producing the conventional multilayer reflective polarizer described above will be briefly described. After four co-extruded groups having different average optical thicknesses forming the core layer are separately co-extruded, the four co-extruded four groups are stretched, And then the four layers are adhered with an adhesive to form a core layer. This is because the peeling phenomenon occurs when the core layer is stretched after bonding the adhesive. Thereafter, the skin layers are bonded to both sides of the core layer. As a result, in order to construct a multi-layer structure, a two-layer structure is folded to form a four-layer structure, and a group (209-layer) is formed through a process of forming a multi-layer structure in a continuous folding manner. It was difficult to form a group in the multilayer in the process. As a result, four groups having different average optical thicknesses have to be separately co-extruded and bonded.

Since the above-described process is intermittently performed, a remarkable increase in the manufacturing cost has been brought about. As a result, the cost of all the optical films included in the backlight unit is the most expensive. As a result, there has been a serious problem that liquid crystal displays other than the reflective polarizer are frequently released even when the decrease in luminance is reduced in terms of cost reduction.

Thus, there has been proposed a reflective polarizer in which a birefringent polymer stretched in the longitudinal direction is arranged in a substrate, not a multilayer reflective polarizer, and a polymer capable of achieving the function of the reflective polarizer is dispersed. 3 is a perspective view of a reflective polarizer 20 including a rod-shaped polymer, in which birefringent polymers 22 stretched in the longitudinal direction are arranged in one direction inside the base material 21. Fig. The birefringent interface between the base material 21 and the birefringent polymer 22 causes a light modulation effect to perform the function of the reflection type polarizer. However, as compared with the above-mentioned alternately stacked reflective polarizer, it is difficult to reflect light in the entire wavelength range of visible light, resulting in a problem that the light modulation efficiency is too low. Accordingly, in order to have a transmittance and a reflectance similar to those of the alternately stacked reflective polarizer, an excessively large number of birefringent polymers 22 must be disposed inside the substrate. Specifically, in order to have optical properties similar to those of the above-described laminate-type reflective polarizer in the substrate 21 having a width of 1580 mm and a height (thickness) of 400 μm or less when a horizontal 32-inch display panel is manufactured on the basis of the vertical cross section of the reflective polarizer, At least 100% of circular or elliptical birefringent polymer 22 having a cross-sectional diameter in the longitudinal direction of 0.1 to 0.3 탆 must be contained. In this case, not only the production cost is excessively increased but also the facilities are excessively complicated, There is a problem that it is difficult to produce the facility itself and thus it is difficult to commercialize it. Further, since it is difficult to make various optical thicknesses of the birefringent polymer 22 contained in the sheet, it is difficult to reflect light in the entire visible light region, and there is a problem that the physical properties are reduced.

In order to overcome this problem, a technical idea including a birefringent island-in-the-sea yarn has been proposed. FIG. 4A is a cross-sectional view of a birefringent island-in-the-sea yarn included in the substrate, and the birefringent island-in-the-sea yarn may generate a light modulation effect at an optical modulation interface between the island portion and the sea portion of the inner portion, and thus, a very large number of the above-described birefringent polymers Optical properties can be achieved even if the island-in-the-sea yarns are not disposed. However, since the birefringent island-in-the-sea yarn is a fiber, problems of compatibility, ease of handling, and adhesion with a substrate which is a polymer have arisen. Furthermore, due to the circular shape, light scattering is induced, and thus the reflection polarization efficiency of the visible wavelength is reduced, and the polarization characteristic is lowered compared to the existing products, thereby limiting the luminance improvement. As the area is subdivided, the voids cause the optical leakage due to light leakage, that is, light loss. In addition, there is a problem that a limitation occurs in the reflection and polarization characteristics due to the limitation of the layer configuration due to the organization of tissue in the form of a fabric.

The first object of the present invention is to be manufactured integrally without forming a separate adhesive layer between each group of the inside of the core layer and between the core layer and the skin layer not only significantly reduce the production cost but also maximize optical properties at a limited thickness A multilayer reflective polarizer can be provided.

A second object of the present invention is to provide a reflective polarizer including a bead coating layer capable of improving scratch resistance while improving optical properties.

In order to solve the above problems, the multilayer radial polarizer of the present invention includes a first layer having in-plane birefringence and a second layer alternated with the first layer in order to transmit the first polarized light irradiated from the outside and reflect the second polarized light. A layer, wherein the first layer and the second layer have different refractive indices in at least one axial direction, the first layer and the second layer extend in at least one axial direction, and the first layer and the second layer The layer forms one repeating unit, and the repeating units form a group to reflect the shear wave (S wave) of a desired wavelength, wherein the groups are two or more, the groups are integrally formed, and the intergroup repeating unit Core layers having different average optical thicknesses thereof, a skin layer integrally formed on at least one surface of the core layer, and a bead coating layer formed on at least one surface of the skin layer.

According to a preferred embodiment of the present invention, the first polarization may be longitudinal, and the second polarization may be transverse.

According to another preferred embodiment of the present invention, the first layer is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC ) Alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene ( ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM) Or phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the present invention, the second layer is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate ( PC) Alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM) ), Phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the present invention, the repeating units may form three groups to reflect light of three wavelength bands.

According to another preferred embodiment of the present invention, the repeating units may form three groups to reflect light of four wavelength bands.

According to another preferred embodiment of the present invention, the desired wavelength may include a visible light band.

According to another preferred embodiment of the present invention, the optical thickness of the repeating units included in the same group may be within 30%, preferably within 20%, more preferably within 15% of the average optical thickness.

According to another preferred embodiment of the present invention, the three reflection bands may include a wavelength band of 450nm, 550nm and 650nm.

According to another preferred embodiment of the present invention, the four reflection bands may include a wavelength band of 350nm, 450nm, 550nm and 650nm.

According to another preferred embodiment of the present invention, the plurality of groups may differ by 5% or more, preferably 10% or more by the average optical thickness of the repeating units.

According to another preferred embodiment of the present invention, the repeating units included in one group may be 25 or more, preferably 50 or more, more preferably 100 or more, and most preferably 150 or more.

According to another preferred embodiment of the present invention, the difference in the refractive index of the first layer and the second layer may be greater than the difference in the refractive index in the axial direction of the extended axial direction.

According to another preferred embodiment of the present invention, the difference between the refractive indices of the first layer and the second layer in the two axial direction is 0.05 or less, the difference in the refractive index in the other one axial direction is 0.1 or more Can be.

According to another preferred embodiment of the present invention, a birefringent interface may be formed between the first layer and the second layer.

According to another preferred embodiment of the present invention, the first layer may have optical birefringence, and the second layer may have optical isotropy.

According to another preferred embodiment of the present invention, the adhesive layer may not be formed between the group and the group.

According to another preferred embodiment of the present invention, the adhesive layer may not be formed between the core layer and the skin layer.

According to another preferred embodiment of the present invention, the skin layer may be stretched.

According to another preferred embodiment of the present invention, the bead coating layer may be a mixture of 30 to 1700 parts by weight of beads with respect to 100 parts by weight of the binder.

According to another preferred embodiment of the present invention, the average particle diameter of the beads may be 1 ~ 30㎛.

According to another preferred embodiment of the present invention, the beads may be any one or more selected from the group consisting of silica, zirconia, titanium dioxide, styrene, propylene, ethylene, urethane and methyl (meth) acrylate.

According to another preferred embodiment of the present invention, the binder may be any one or more selected from the group consisting of aliphatic urethane acrylate, epoxy acrylate, melamine acrylate and polyester acrylate.

According to another preferred embodiment of the present invention, the thickness of the binder may be 0.5 ~ 50㎛.

According to another preferred embodiment of the present invention, the arithmetic mean roughness (Ra) of the bead coating layer may be 0.1 ~ 5㎛.

According to another preferred embodiment of the present invention, the beads may be a mixture of monodisperse beads and polydisperse beads.

Hereinafter, terms used in this specification will be briefly described.

'Polymer has birefringence' means that when light is irradiated to fibers of different refractive index along the direction, the light incident on the polymer is refracted into two light beams with different directions.

'Isotropic' means that the refractive index is constant regardless of direction when light passes through the object.

'Anisotropy' means that the optical properties of an object are different according to the direction of light, and anisotropic objects have birefringence and correspond to isotropy.

'Light modulation' means that the irradiated light reflects, refracts, scatters, changes the intensity of the light, the period of the wave or the nature of the light.

The 'aspect ratio' means the ratio of the shortening length to the longest length based on the vertical section in the longitudinal direction of the elongated body.

"Mono Dispersive" refers to particles having the same particle size, and means that the particle size dispersion index (CV) is 9% or less as shown in FIG. 4B.

"Poly Dispersive" means that particles having different particle diameters are mixed. In the present invention, it means that the particle size distribution index is 20% or more.

Since the reflective polarizer of the present invention is formed integrally with a plurality of groups having different average optical thicknesses, a separate adhesive layer and / or protective layer PBL is not included in the core layer and between the core layer and the skin layer. This makes it possible to remarkably reduce the manufacturing cost and to maximize optical properties at a limited thickness. In addition, since a plurality of groups having different average optical thicknesses are formed, all S waves in the visible light wavelength region can be reflected. This makes it possible to remarkably reduce the manufacturing cost and to maximize optical properties at a limited thickness.

Furthermore, since the bead coating layer is included, scratch resistance can be improved while improving optical properties such as luminance.

1 is a schematic view for explaining the principle of a conventional reflective polarizer.
2 is a cross-sectional view of a currently used multi-layer reflective polarizer (DBEF).
3 is a perspective view of a reflection type polarizer including a bar-shaped polymer.
4A is a cross-sectional view showing a path of light incident on a birefringent island-in-the-sea yarn used in a reflective polarizer.
Figure 4b is a photograph and graph showing the shape and particle size distribution of the polydisperse particles and mono-disperse particles.
5 is a cross-sectional view of a multilayer reflective polarizer according to an exemplary embodiment of the present invention.
6 is a cross-sectional view of a multilayer reflective polarizer according to another exemplary embodiment of the present invention.
7 is a cross-sectional view of a multilayer reflective polarizer according to another preferred embodiment of the present invention.
Figure 8 is a perspective view of the distribution plate of the slit-shaped extrusion mold that can be used in the present invention, Figure 9 is a bottom view of them, Figure 10 is a bond.
11 is a cross-sectional view of a multilayer composite according to a preferred embodiment of the present invention.
12 is a schematic diagram comprising two first press means to form two multi-layered composite flows in accordance with a preferred embodiment of the present invention.
Figure 13 is a schematic diagram comprising two second pressurizing means to form two multilayered composite flows in accordance with a preferred embodiment of the present invention.
Figure 14 is a schematic diagram showing the laminated portion of the multi-layered composites and skin layer according to an embodiment of the present invention.
15 is a cross-sectional view of a coat-hanger die according to one preferred embodiment of the present invention, and FIG. 16 is a side view.
17 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to a preferred embodiment of the present invention.
18 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to another preferred embodiment of the present invention.
19 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to another preferred embodiment of the present invention.
20 is an exploded perspective view of a liquid crystal display device including the reflective polarizer of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in more detail with reference to the accompanying drawings.

According to a preferred embodiment of the present invention, the multilayer reflective polarizer of the present invention alternately with the first layer and the first layer having in-plane birefringence in order to transmit the first polarized light irradiated from the outside and reflect the second polarized light. And a second layer, wherein the first layer and the second layer have different refractive indices in at least one axial direction, the first layer and the second layer extending in at least one axial direction, and the first layer And the second layer form one repeating unit, and the repeating units form a group to reflect the shear wave (S wave) of a desired wavelength, the group is two or more, and the groups are integrally formed, and the group And a core layer having different average optical thicknesses of the liver repeating units, a skin layer integrally formed on at least one surface of the core layer, and a bead coating layer formed on at least one surface of the skin layer.

5 is a cross-sectional view of a multilayer reflective polarizer according to an exemplary embodiment of the present invention. Specifically, skin layers 189 and 190 are integrally formed on both surfaces of the core layer 180, and bead coating layers 191 and 192 are formed on one surface of the skin layers 189 and 190. First, the core layer 180 is divided into two groups A and B. In the drawing, a dotted line dividing groups A and B means a virtual line. In the group A, the first layers 181 and 183 corresponding to the first component and the second layers 182 and 184 corresponding to the second component are alternately stacked. Herein, the first layer 181 and the second layer 182 are defined as one repeating unit (R1), and the group A may include at least 25 repeating units. Group B also alternately stacks the first layer (185, 187) and the second layer (182, 184) corresponding to the second component. Here, the first layer 185 and the second layer 186 are defined as one repeating unit (R2), and the group A may include at least 25 or more repeating units, preferably 50 or more, more preferably May be 100 or more, most preferably 150 or more. The thicknesses of the first layer and the second layer may be the same.

On the other hand, the average optical thicknesses of the repeating units (R1) included in the group A and the average optical thicknesses of the repeating units (R2) included in the group B are different. This makes it possible to reflect different wavelengths of S waves. In addition, the optical thickness of the repeating units included in the group A may have an optical thickness deviation of less than 30%, preferably less than 20%, more preferably less than 15% based on the average optical thickness of the group A. In this case, the optical thickness means n (refractive index) x d (physical thickness). On the other hand, the wavelength of light and the optical thickness are defined by the following relational expression (1).

[Relation 2]

? = 2 (n ₁ d ₁ + n ₂ d ₂ )

(Nm), n ₁ is refractive index of one layer, n ₂ is refractive index of two layers, d ₁ is physical thickness of one layer (nm), and d ₂ is physical thickness of two layers (nm).

Therefore, when the average optical thickness of the group A is 200 nm, it is possible to reflect a transverse wave (S wave) of a wavelength of 400 nm by the above-mentioned relational expression 2. [ In this case, if the thickness deviation is 20%, the wavelength band of about 320 to 480 nm can be covered. If the average optical thickness of the repeating units (R2) in the group B is 130 nm, the transverse wave (S wave) of 520 nm wavelength can be reflected by the relational expression 1. If the thickness deviation is 20%, the wavelength band of about 420 to 620 nm And in this case can be partially overlapped with the wavelength band of the group A, thereby maximizing the light modulation effect. In addition, since the first layer having the in-plane birefringence must transmit the P wave and reflect the S wave, the refractive index (n) can be set based on the thickness direction (refractive index of the z axis) through which the light passes and the average optical thickness can be calculated.

On the other hand, they are integrally formed without an adhesive layer between the group and the group. And is also integrally formed between the core layer and the skin layer. As a result, it is possible not only to prevent deterioration of optical properties due to the adhesive layer, but also to add more layers to a limited thickness, thereby significantly improving optical properties and significantly reducing manufacturing costs. Further, since the skin layer is produced simultaneously with the core layer and then the stretching process is performed, unlike the conventional adhesion of the core layer after stretching to the unstretched skin layer, the skin layer of the present invention can be stretched in at least one axial direction. As a result, the surface hardness is improved as compared with the non-drawn skin layer, and the scratch resistance is improved and the heat resistance can be improved.

The bead coating layers 191 and 192 are formed on one surface of the 189 and 190. The bead coating layer used in the present invention is formed to improve scratch resistance at the same time to improve the optical properties, for this purpose, according to one embodiment, the bead coating layer is 30 to 1700 beads to 100 parts by weight of the binder The weight part may be mixed. Preferably, when the bead coating layer is formed on both sides of the reflective polarizer, one side may include 30 to 1700 parts by weight of beads and the other side of 30 to 200 parts by weight of beads.

First, the beads 193 and 194 that can be used in the present invention may preferably be used alone or in combination with silica, zirconia, titanium dioxide, styrene, propylene, ethylene, urethane and methyl (meth) acrylate. In this case, the average particle diameter of the beads may be 1 ~ 30㎛, monodisperse beads or polydisperse bead particles may be used alone or in combination as appropriate.

Next, the binder that can be used in the present invention may use a binder used in a conventional bead coating layer, preferably selected from the group consisting of aliphatic urethane acrylate, epoxy acrylate, melamine acrylate and polyester acrylate It may be any one or more. Preferably, the photocurable aliphatic urethane acrylate having a weight average molecular weight of 1,000 to 10,000 may be used. For example, the aliphatic urethane acrylate is first synthesized by reacting an aliphatic polyol and a diisocyanate to form an isocyanate, and then, an acrylate having a hydroxyl group, for example, ethyl hydroxyacrylate isocyanate. It can be used prepared by reacting with, can also be purchased commercially.

On the other hand, the thickness of the binder may be 0.5 ~ 50㎛. Therefore, as shown in FIG. 5, the thickness of the binder may be thicker than the diameters of the beads 193 and 194, and some of the beads 191 may form irregularities to roughen the outside of the bead coating layer. In this case, the arithmetic mean roughness Ra of the bead coating layer may be 0.5 to 3 μm. If the arithmetic mean roughness Ra is less than 0.5 μm, the light diffusion effect is reduced. If the arithmetic mean roughness Ra is less than 0.5 μm, curling may occur or the polarizer may be distorted.

In addition, 0.1 to 20 parts by weight of the photopolymerization initiator may be further included with respect to 100 parts by weight of the binder. If the content of the added photopolymerization initiator is less than 0.1% by weight, there is a problem that the hardness of the cured product is lowered. If the content of the photopolymerization initiator is more than 20% by weight, the physical properties of the cured product are lowered, which is not preferable. Photopolymerization initiators that can be used in the present invention include 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, benzaldehyde, anthraquinone, 3-methylacetophenone, 4-chlorobenzophenone, 4 , 4'-dimethoxybenzophenone, benzoinpropyl ether, benzoin ethyl ether, 1- (4-isopropyl-phenol) -2-hydroxy-2-methylpropan-1-one, thioxanthone, benzophenone, 2,4,6-trimethylbezoyl-diphenylphosphine, and commercially supplied products include Irgacure184,651,500,819,907,1800 (Shiba Gauge), Darocure 1116,1173 (Merck), Lucirine LR8728 (BASF), Micure HP-8, TPO, CP-4, BK-6 (Miwon Corp.) and the like can be used alone or in combination of two or more.

6 is a cross-sectional view of a multilayer reflective polarizer according to another exemplary embodiment of the present invention. 5, the three groups A, B, and C having different average optical thicknesses are formed inside the core layer, and the average optical thicknesses of the repeating units between the groups are different.

7 is a cross-sectional view of a multilayer reflective polarizer according to another preferred embodiment of the present invention. Specifically, the core layer is formed of four groups, and each of the groups can be adjusted in the average optical thickness to cover the light wavelength band of 350 nm, 450 nm, 550 nm and 650 nm, respectively. In this case, the outer layer of the core layer is formed with groups having a large average optical thickness, and groups having a small average optical thickness in the inner layer can be formed. On the other hand, in order to cover the entire visible light region, the average optical thickness of the repeating units should be determined so as to correspond to various light wavelengths. To set the average optical thickness of the repeat units per group within the core layer to correspond to the optical wavelength band of 350 nm, 450 nm, 550 nm and 650 nm, the average optical thickness of the first component between the groups may be different by at least 5% , And more preferably 10% or more. This allows reflection of the S wave in the entire visible region.

Meanwhile, in FIG. 7, the thickness of the binder in the bead coating layers 195 and 196 formed on one surface of the skin layer may be smaller than the diameter of some beads 198 of the beads 197 and 198. Through this, surface roughness may be added to the surface of the bead coating layer.

According to a preferred embodiment of the present invention, a birefringence interface may be formed between the first layer and the second layer forming the core layer. Specifically, in the multilayer reflective polarizer in which the first layer and the second layer are alternately laminated, the substantial coincidence or incoincidence of the refractive index along the X, Y and Z axes in the space between the first and second layers is determined by the axis Which affects the degree of scattering of the polarized light beam. Generally, the scattering ability changes in proportion to the square of the refractive index mismatch. Thus, the greater the degree of discrepancy in refractive index along a particular axis, the more scattered light rays are polarized along that axis. Conversely, when the inconsistency along a particular axis is small, the polarized light rays along the axis are scattered to a lesser degree. If the refractive index of the second layer substantially coincides with the refractive index of the first layer along an axis, incident light polarized with an electric field parallel to this axis is not scattered regardless of the size, shape and density of the portion of the first layer Will pass through the first layer. Also, when the refractive index along the axis is substantially coincident, the light rays pass through the object without being substantially scattered. More specifically, the first polarized light (P wave) is transmitted without being influenced by the birefringent interface formed at the boundary between the second layer and the first layer, while the second polarized light (S wave) The light is affected by the birefringent interface formed at the boundary. As a result, the P wave is transmitted and the S wave is modulated by light such as scattering and reflection of light, resulting in separation of polarized light.

Accordingly, since the first layer and the second layer may have a birefringent interface at the interface thereof to cause a light modulation effect, when the second layer is optically isotropic, the first layer may have birefringence. Specifically, when the refractive index in the x-axis direction is nX1, the refractive index in the y-axis direction is nY1, the refractive index in the z-axis direction is nZ1, and the refractive indexes of the second layer are nX2, nY2 and nZ2, Plane birefringence may occur. More preferably, the first layer and the second layer may differ in at least one of X, Y, and Z-axis refractive indexes, and more preferably, when the extension axis is the X-axis, Is 0.05 or less, and the difference in refractive index with respect to the X-axis can be 0.1 or more.

On the other hand, when the difference in the refractive index is 0.05 or less, it is interpreted as matching.

Meanwhile, according to a preferred embodiment of the present invention, the total number of layers of the multilayer reflective polarizer may be 100 to 2000. The thickness range of the repeating unit can be appropriately designed according to the wavelength range of the desired light and the refractive index, and may preferably be 65 to 300 nm. The thicknesses of the first layer and the second layer forming the repeating unit may be substantially the same or different. In the present invention, the core layer may have a thickness of 10 to 300 占 퐉 and the skin layer may have a thickness of 50 to 190 占 퐉, but the present invention is not limited thereto.

Next, a method of manufacturing a multilayer reflective polarizer integrally formed without including the adhesive layer of the present invention will be described.

First, in step (1), the first component, the second component, and the skin layer component are supplied to the extruding portions, respectively. The first component is a polymer dispersed in the second component forming the base material, and may be used without limitation as long as it is used in a reflective polarizer in which a conventional polymer is dispersed. Preferably, the first component is polyethylene naphthalate (PEN), copolyethylene Polymers such as phthalates (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloys, polystyrene (PS), heat resistant polystyrene (PS), polymethylmethacrylate (PB), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyesters (SI) and cycloolefin polymers Number and may be more preferably PEN.

The second component forms a substrate and can be used without limitation as long as it is used as a material of a substrate in a reflective polarizer in which a polymer is dispersed. Preferably, the second component is selected from the group consisting of polyethylene naphthalate (PEN), co-polyethylene naphthalate ), Polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat resistant polystyrene (PS), polymethylmethacrylate (PMMA), polybutylene terephthalate ), Polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP) The olefin polymer may be used singly or in combination Can be used and may be more preferably, dimethyl 2,6-naphthalenedicarboxylate, dimethyl terephthalate and ethylene glycol, Im chroman-hexane dimethanol (CHDM), such as the monomers are suitably polymerized co-PEN.

The skin layer component can be used without limitation as long as it is usually used in a reflective polarizer in which a polymer is dispersed. Preferably, the skin layer component may be a polyethylene terephthalate (PET), a polycarbonate (PC), a polycarbonate (PC) ), Heat resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane ), Polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile blend (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM) (UF), melamine (MF), unsaturated polyesters (UP), silicon (SI) and cycloolefin polymers. The polycarbonate alloy is preferably made of a polycarbonate and a modified glycol polycyclohexylene dimethylene terephthalate (PCTG), more preferably a polycarbonate and a modified glycol polycyclohexane (PCTG) may be a polycarbonate alloy having a weight ratio of 5:95 to 95: 5. In the meantime, the skin layer of the present invention is preferably made of a material having a small change in refractive index in the spreading and stretching process, more preferably polycarbonate or polycarbonate glass.

Meanwhile, the first component, the second component, and the skin layer component may be separately supplied to the independent extrusion units. In this case, the extrusion unit may be composed of three or more. It is also included in the present invention to feed one extruded portion including a separate supply path and a distribution port so that the polymers do not mix. The extruder may be an extruder, which may further include a heating means or the like to convert the supplied polymers in the solid phase into a liquid phase.

Next, as step (2), two or more multi-layer composite streams in which the repeating units of the first component and the second component are alternately stacked are formed, and each of the multi-layer composite streams is formed so as to reflect a transverse wave , And the first component and the second component transferred from the extrusion unit are put into a plurality of compound extrusion compartments to form two or more multilayer composite streams having different average optical thicknesses of the repeating units.

Specifically, FIGS. 8 to 10 are a perspective view, a bottom view, and a coupling diagram of the distribution plate of the slit-type extrusion mold that can be used in the present invention. FIG. 6 is a perspective view showing the coupling structure of the detent plates of the slit-type extrusion apparatus. FIG. The first receiving distribution plate S1 located at the upper end of the slit-shaped extrusion opening may be constituted by the first component supply path 50 and the second component supply path 51 in the interior thereof. So that the first component transferred through the extrusion portion can be supplied to the first component supply path 50 and the second component can be supplied to the second supply path 51. In some cases, a plurality of such supply paths may be formed. Polymers that have passed through the first receiving distribution plate S1 are transported to the second receiving distribution plate S2 located below. The first component introduced through the first component supply path 50 is branched and transferred to the plurality of first component supply paths 52 and 53 along the flow path. In addition, the second component injected through the second component supply path (51) is branched and transferred to the plurality of second component supply paths (54, 55, 56) along the flow path. The polymers that have passed through the second detention distribution plate S2 are transferred to the third detention distribution plate S3 located below.

The first component supplied through the first component supply paths 52 and 53 is connected to the first component supply paths 60, 61, 62, 63, 67, 68, 69, 70 along the flow path. Similarly, the second components injected through the second component supply paths 54, 55 and 56 are respectively connected to the second component supply paths 57, 58, 59, 64, 65, 66 , 71, 72 and 73 along the flow path. The first component introduced through the first component supply passages 60 and 67 of the first component supply passages formed in the third pickling distribution plate S3 is supplied to the first component supply passages 60 and 67, To the first flow path 74 of the first flow path 74. Likewise, the first component injected through the second component supply paths 57, 64 and 71 of the second component supply paths formed in the third pickling distribution plate S3 flows through the second component supply path 57, To the second one of the first and second flow paths (75). In this way, the first component transferred through the first component supply paths of the third holding distribution plate S3 is distributed to the odd-numbered flow paths 74, 76, 78, 80 of the fourth holding distribution board S4 And the second component transferred through the second component supply paths of the third component distribution plate S3 is transferred to the even flow channels 75, 77, 79 of the fourth component distribution plate S4. Whereby the first component and the second component can be alternately stacked. According to the above-described principle, the lower portion of the fourth housing distribution plate S4 may further include a separation plate (not shown) perpendicular to the flow direction of the fourth housing distribution plate and having a larger number of flow channels, It is obvious to those skilled in the art to extend the number of channels by the number. On the other hand, the first component transferred through the odd-numbered flow paths 74, 76, 78, 80 of the fourth bundled distribution plate S4 is divided into the odd-numbered flow paths 81, And the second component transferred through the even-numbered flow paths 75, 77 and 79 of the fourth holding distribution plate S4 is transferred to the fifth holding distribution plate 82, 84, 86, 88, 90, 91, 92 of the first to fifth flow paths S5, S5. FIG. 9 is a bottom view of the slit-type extrusion mold of FIG. 8, and the discharge path of the fifth mold distribution plate S5 is integrally formed with the slit type, not spaced apart from the hole type. Whereby the first component and the second component form respective layers. Therefore, the number of layers of the multilayer composite stream may be determined according to the number of slits of the fifth mold distribution plate S5. The number of preferable layers may be 100 or more, more preferably 150 or more, more preferably 200 or more, and most preferably 300 or more. Thereafter, the multilayer composite flow is discharged through the discharge port 94 of the sixth holding distribution plate. FIG. 11 is a cross-sectional view of the multilayer composites in which the first components 100, 102 and the second components 101, 103 are alternately stacked. In this case, one of the first component 100 and the deposited second component 101 can be defined as a repeating unit, and one compound stream includes a plurality of repeating units.

By the way, Figures 8 to 10 are examples of the detention distribution plate that can be used in the slit-type extrusion mold that can be used of the present invention, the detention distribution plate for producing a multilayer composite flow of the first component and the second component alternately laminated It will be apparent to those skilled in the art that the number, structure, size of the hole, size, shape, slit size of the fifth mold distribution plate, size of the discharge hole, etc. are properly designed and used by those skilled in the art. On the other hand, the diameter of the slits in the bottom view of the fifth housing distribution plate may be 0.17 to 0.6 mm, and the diameter of the discharge port may be 5 to 50 mm, but the present invention is not limited thereto. The diameter of the slit and the like are well known to those skilled in the art.

On the other hand, the plurality of multi-layer composite streams have different optical thicknesses, the number of repeating units, etc. of the repeating units of alternately stacked first and second components forming different multi-layer composite streams to cover different wavelength ranges of light, can do. For this purpose, the size of the spinneret, the thickness of the slit, the shape, or the number of layers may be different from each other in each multilayer extrusion opening. The reflection type polarizer, which is finally manufactured through the spreading and stretching processes, has a plurality of repeating units stacked therein to form one group, and each group can be set to have a different average optical thickness.

More specifically, the optical thickness means n (refractive index) x d (physical thickness). Therefore, if two multilayer composite streams are formed, the optical thickness is proportional to the physical thickness (d) if there is no difference in refractive index between the first and second components of the multi-layer composite stream. Therefore, by varying the average value of the physical thickness (d) of the repeating units of the first component and the second component contained in each of the multi-layer composite streams, it is possible to derive the difference in optical thickness between the multi-layer composite streams. For this purpose, the thickness of the slits included in the slit-type extrusion opening can be designed differently for each extrusion opening, thereby making it possible to produce multi-layer composite streams having different average optical thicknesses.

 On the other hand, in order to cover the entire visible light region, the average optical thickness of the multilayer composite flow must be determined so as to correspond to various light wavelengths. For example, in order to set the average optical thicknesses of the repeating units of the multi-layer composite stream such that three complex streams are formed and correspond to 450 nm, 550 nm and 650 nm of the wavelength range of each light, the average optical thickness May be at least 5% different, more preferably at least 10% different. This allows reflection of the S wave in the entire visible region. In this case, the thicknesses of the first component and the second component forming the same repeating unit may be the same.

 Also, the number, the cross-sectional area, the shape, the diameter of the slit, and the like of the spinneret holes may be the same or different in the slit-type extrusion nozzle forming one multilayer composite flow. Furthermore, the optical thickness of the repeating units forming the same multilayered composite may have a deviation of preferably within 30%, more preferably within 20% and even more preferably within 15% of the average optical thickness. For example, if the average optical thickness of the repeating units of the first multi-layer composite stream is 200 nm, the repeating units forming the same first multi-layer composite stream may have an optical thickness variation within about 20%. On the other hand, the wavelength of light and the optical thickness are defined by the following relational expression (1).

[Relationship 1]

λ = 4nd

Where? Is the wavelength of light (nm), n is the refractive index, d is the physical thickness (nm)

Therefore, when the optical thickness (nd) deviates, it is possible to cover not only the wavelength of the target light but also the wavelength range of the light including the target, thereby greatly improving uniform optical properties. Meanwhile, d denotes the thickness of one layer, and since the repeating unit is composed of two layers of the first component and the second component, if the physical thickness of the first component and the second component is the same, the repeating unit and the wavelength of light Can be defined according to relation 2 below.

[Relation 2]

? = 2 (n ₁ d ₁ + n ₂ d ₂ )

(Nm), n ₁ is refractive index of one layer, n ₂ is refractive index of two layers, d ₁ is physical thickness of one layer (nm), and d ₂ is physical thickness of two layers (nm).

 The deviation of the optical thickness described above can be attained through imparting a deviation to the number, the cross-sectional area, the shape, the diameter of the slit or the like of the fixing hole in one slit-type extrusion mouth, or naturally achieved through a fine pressure distribution in the spreading process or the like You can.

Therefore, the plurality of multi-layered composite streams of the present invention can cover the entire visible light region by setting the average optical thicknesses of the repeating units constituting the composite stream differently, It is possible to reflect an S wave in a wide wavelength range by giving a deviation. 8 to 10 illustrate that one multilayered composite flow is produced from one slit-type extrusion die, but a section is added to the inside of the slit-shaped extrusion die to produce a plurality of multilayered composite flows. It is also within the scope of the present invention to correspond to the integrated slit-type extruded through one laminated through one. In addition, the thickness of the slit included in the slit-type extrusion slot can be designed differently for each extrusion slot to produce multi-layer composite streams having different average optical thicknesses.

 According to another preferred embodiment of the present invention, the first component conveyed in the extrusion part between steps (1) and (2) may include a plurality of components having different ejection amounts to have different average optical thicknesses 1 pressing means, respectively, into different slit-type extrusion ports. Specifically, FIG. 12 is a schematic view including a first pressurizing means for forming two multi-layered composite flows, in which a first component conveyed from an extruder (not shown) includes the plurality of first pressurizing means 130 and 131. It is branched to and supplied to the respective slit-type extrusion holes 132 and 133 separately from the respective first pressing means 130 and 131. In this case, the first pressurizing means 130 and 131 have different discharge amounts, and an area difference occurs. When the slits 132 and 133 have the same specifications (when the diameters of the slits are the same) The average optical thickness of the first multi-layer composite stream and the second multi-layer composite stream formed through the second multi-layer composite stream may be different.

To this end, the discharge amount of the first pressurizing means 130 and 131 may be preferably 1 to 100 kg / hr, but is not limited thereto.

On the other hand, one first pressing means feeds the first component to the two slit-type push-pull corners and the two multi-layer composite streams formed by the two slit-type push-pull cores are joined to form one multi-layer composite stream, It is also possible that a group is formed. In this case, the final reflection type polarizer may be formed of four groups through four first component pressing means and eight slit type extrusion / detaching mechanisms. It is also possible that one of the first pressing means transports the first component to three or more slit-shaped push-pull tabs.

According to another preferred embodiment of the present invention, the second component conveyed in the extrusion part between the step (1) and step (2) includes a plurality of components having different discharge amounts in order to have different average optical thicknesses Respectively, through the two pressing means. Specifically, FIG. 13 is a schematic view including two second pressing means to form two multi-layered composite flows, wherein the second component conveyed from the extrusion unit (not shown) is the plurality of second pressing means 140, 141. ) And is supplied separately to the respective slit-type extrusion holes 142, 143 in the respective second pressing means 140, 141. At this time, the first pressurizing means 150 and 151 have different discharging amounts, and through which the slits 152 and 153 have the same specifications (when the shape diameters of the supply conduits, etc. are the same) Layer composite stream and the second component of the second multi-layer composite stream may have different average optical thicknesses. For this, the discharge amount of the second pressing means 150 and 151 may be preferably 1 to 100 kg / hr, but is not limited thereto.

On the other hand, one second pressurizing means feeds the second component to the two slit-type extrusion drills, and the two multi-layer composite streams formed in the two slit-type extrusion drums are joined to form one multi-layer composite stream, It is also possible that a group is formed. In this case, the final reflection type polarizer may be formed of four groups through four second component pressing means and eight slit-type extrusion / detaching units. It is also possible that one second pressing means transports the second component to three or more slit-shaped extrusion orifices.

In the next step (3), the two or more multilayer composite streams are combined into one to form a core layer. Specifically, FIG. 14 is a schematic view showing a lamination portion of a multilayer composite stream. The core layer 165 is formed by laminating a plurality of multilayer composite streams 161, 162, 163, and 164 manufactured through respective slit-type extrusion holes. To form. Meanwhile, the lapping step may be performed in a separate place, or in a case where an integral slit-type extrusion / detaching unit is used, the laminating unit may be joined together through a separate collecting / collecting distribution plate. When the number of the multi-layered composite streams is large, it is also possible to perform a multi-stage laminated structure in which some multi-layer composite streams are first lapped and lapped again to facilitate laminating. Meanwhile, the skin layer component may also be laminated simultaneously or sequentially with the core layer in the lamination portion.

Meanwhile, a separate preliminary spreading step may be further carried out between the steps (2) and (3) or between the steps (3) and (4) to facilitate the spreading of the repeating units described below.

Next, in step (4), at least one side of the core layer laminated is joined with the skin layer component transferred from the extrusion part. Preferably, the skin layer component may be laminated on both sides of the core layer. When the skin layers are laminated on both sides, the material and the thickness of the skin layer may be the same or different from each other. Meanwhile, as described above, when the skin layer components are simultaneously laminated in the lamination part of step (3), this step may be omitted.

Next, in step (5), the skin layer is spread and the core layer is spread in the flow control part. Specifically, FIG. 15 is a cross-sectional view of a coat-hanger die, which is a kind of preferred flow control unit that may be applied to the present invention, and FIG. 16 is a side view. The degree of spreading of the core layer can be appropriately adjusted to adjust the repeating unit to have an optical thickness suitable for reflecting light of a desired wavelength. This can be suitably designed in consideration of further reducing the optical thickness in the subsequent stretching process. In detail, since the core layer in which the skin layer transferred through the flow path is laminated in FIG. 15 is widely spread from side to side in the coat-hanger die, the first component included therein is also widely spread from side to side. In addition, as shown in the side view of Figure 16, the coat hanger die is wide spread from side to side but has a structure that is reduced up and down, so that the skin layer is spread in the horizontal direction of the laminated core layer or reduced in the thickness direction. This is based on Pascal's principle, in which the fluid in the enclosure is guided to spread widely in the width direction by the principle that the pressure is transmitted to the fine portion by a certain pressure. Therefore, the outlet size is wider in the width direction than the die inlet size, and the thickness is reduced. This requires the use of the Pascal principle in which the molten liquid material can flow and shape controlled by pressure in a closed system, preferably a polymer flow rate and viscosity induction such that a flow of laminar flow of less than 2,500 Reynolds numbers is preferred. When the flow of the turbulent flow is 2,500 or more, the induction of the plate-like type becomes uneven, and there is a possibility that the optical characteristic is varied. The left and right die width of the outlet of the coat-hanger die may be between 800 and 2,500 mm and the fluid flow of the polymer is required to regulate the pressure so that the Reynolds number does not exceed 2,500. The reason is that the polymer flow becomes turbulent and the arrangement of the cores may be disturbed. Also, the internal temperature may be 265 to 310 ° C.

The flow control unit may be a T-die or a manifold type Coat-hanger die capable of inducing the spread of the repeating unit, but is not limited thereto, and may be used without limitation as long as it can induce spreading of the core layer.

The manufacturing method of the present invention requires a separate adhesive layer and / or a protective layer (PBL) in the core layer since a plurality of multi-layer composite streams having different average optical thicknesses are manufactured using a plurality of composite extrusion / It is possible to reflect all of the S waves in the visible light wavelength range. Also, since the skin layer is formed on at least one surface of the core layer in a molten state, the skin layer is not subjected to a separate adhesion step. This makes it possible to remarkably reduce the manufacturing cost and to maximize optical properties at a limited thickness.

According to a preferred embodiment of the present invention, after the step (5), (6) cooling and smoothing the polarizer induced by the spread transferred from the flow control unit, (7) stretching the polarizer after the smoothing step ; And (8) heat setting the stretched polarizer.

First, in step (6), cooling and smoothing of the polarizer transferred from the flow control unit may be performed by cooling used in the manufacture of a conventional reflective polarizer to solidify it, and then may be performed by a casting roll process or the like.

Thereafter, a step of stretching the polarizer through the smoothing step is performed. The stretching may be performed through a conventional stretching process of a reflective polarizer, thereby causing a refractive index difference between the first component and the second component to cause a light modulation phenomenon at the interface, and the stretch- The optical thickness corresponding to the desired wavelength range is finally obtained. Therefore, in order to adjust the optical thickness of the repeating unit in the final reflective polarizer, it can be appropriately set in consideration of the slit diameter, spreading inducing condition, and stretching ratio of the slit-type extrusion / For this purpose, the uniaxial stretching or biaxial stretching can be preferably performed in the stretching step, and more preferably uniaxial stretching can be performed. In the case of uniaxial stretching, stretching can be performed in the longitudinal direction. The stretching ratio may be 3 to 12 times. On the other hand, a method of changing an isotropic material to birefringent is commonly known. For example, when stretching under appropriate temperature conditions, polymer molecules may be oriented so that the material becomes birefringent.

Next, the final reflective polarizer may be manufactured by performing heat setting of the stretched polarizer as (8). The thermal fixation may be heat-set through a conventional method, preferably at 180 to 200 ° C for 0.1 to 3 minutes through an IR heater.

On the other hand, in the present invention, when the average optical thickness of the target repeating unit between groups is determined, the reflection type polarizer of the present invention can be manufactured by properly controlling the slit size, the size of the flow control unit, and the stretching ratio .

Thereafter, the bead coating layer may be coated on at least one surface of the heat-fixed reflective polarizer and dried. In this case, a bead, a binder, and a photopolymerization initiator are mixed in a solvent such as ether, and the coating solution is coated on at least one side of the polarizer through a gravure method, and then a final bead coating layer may be formed through a curing and drying process. . Solvents that can be used include alcohols such as methanol, ethanol, propanol and isopropanol, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as methyl acetate and ethyl acetate, aromatics such as toluene, benzene and xylene Compounds, ethers, and the like can be used, and in order to facilitate the solubility and drying process of the organic matter, it is more preferable to prepare a mixture of a solvent such as a ketone solvent or toluene. However, it is not necessarily limited thereto. In addition, the amount of the solvent should be appropriately adjusted so as not to be too small or too large, it is possible to use alone or mixed, the solvent may be used 30-200 parts by weight, more preferably 80-120 parts by weight relative to the binder. If the solvent is less than 30 parts by weight with respect to 100 parts by weight of the binder, the viscosity is high, the thickness of the coating film is thick and adhesion with the substrate is lowered, if it exceeds 200 parts by weight, the viscosity is low, the coating film is low, the hardness may be reduced.

On the other hand, the bead coating layer may further include an antistatic agent for the antistatic effect. In this case, a quaternary ammonium salt-based polymer antistatic agent may be used as an antistatic agent. The polymer antistatic agent may be used in an amount of 20 parts by weight or less in the hard coating solution. Preferably 3-12 weight part is preferable. Various products are known, such as NanoCamtech's ELECON-100ED, ELECON-1700, Moa Chem's MORESTAT ES-7205, MORESTAT ES-7500, Sino-Japan Emulsion's JISTAT 2000 / 2000N, and Japan's First Pharmaceutical Co., Ltd. PU 101. Can be. Light stabilizers added for the UV stability of the hard coating liquids for the diffusion film and the protective film include Tinuvin 144, Tinuvin 292, Tinuvin 327, Tinuvin 329, Tinuvin 5050, and Tinuvin 5151 from Ciba Geigy. Examples include 22, LOWILITE 26, LOWILITE 55, LOWILITE 62, and LOWILITE 94.

The binder composition may appropriately contain one or more additives such as a light stabilizer, an ultraviolet absorber, an antistatic agent, a lubricant, a leveling agent, an antifoaming agent, a polymerization accelerator, an antioxidant, a flame retardant, an infrared absorber, a surfactant, and a surface modifier.

According to another preferred embodiment of the present invention, the first layer and the second component alternately laminated core layer and remind An apparatus for manufacturing a multilayer reflective polarizer comprising a skin layer formed on at least one surface of a core layer, the apparatus comprising: three or more extruded portions into which a first component, a second component, and a skin layer component are separately introduced; Layered composite streams in which the repeating units of the first component and the second component are alternately laminated, and each of the multi-layer composite streams includes a plurality of multi-layer composite streams, A spin block including a composite extrusion nozzle for injecting a first component and a second component to produce two or more multi-layer composite streams having different average optical thicknesses of the repeating units; A collection block for forming a core layer by laminating two or more multi-layer composite streams transferred from the spin block part; A feed block part communicating with the extruder into which the skin layer component is injected and joining the skin layer to at least one surface of the core layer conveyed in the collection block part; And a flow control unit for guiding the spread of the core layer to which the skin layer conveyed in the feed block unit leads the spreading of the core layer.

17 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer in which a skin layer and a core layer are integrally formed in accordance with a preferred embodiment of the present invention. Specifically, the first extrusion part 220 to which the first component is injected, the second extrusion part 221 to which the second component is injected, and the third extrusion part 222 to which the skin layer component is injected are included. The first extrusion part 220 is connected to the spin block part C including the four slit type extrusion tools 223, 224, 225 and 226. At this time, the first extruder 220 supplies the first slit extruded holes 223, 224, 225, and 226 in a molten state. The second extruded portion 221 is also connected to the spin block portion C and supplies the second component to the four slit-shaped extrusion orifices 223, 224, 225, and 226 contained therein in a molten state. The four components of the multi-layer composite stream are alternately stacked with the first component and the second component through the four slit-type extrusion ports 223, 224, 225, and 226, and the average optical thicknesses of the repeating units are different. For this purpose, the respective slit diameters of the four slit-shaped extrusion ports may be different. The four slit-type extrusion holes 223, 224, 225, and 226 may be the slit type extrusion holes shown in FIG. 8. In addition, although four slit-type extrusion / detachment mechanisms have been described as an example, it is also within the scope of the present invention that a single slit-type extrusion / detachment mechanism can be used. The four multi-layer composite streams produced through the four slit-shaped extrusion ports 223, 224, 225 and 226 are joined together in the collection block section 227 to form one core layer. In this case, the collection block portion 227 may be formed separately or may be combined with the multi-layer composite streams in the form of a bundle of nuts in the slit-type extrusion slot when a single slit-type extrusion slot is used. The core layer laminated in the collection block portion 227 is transferred to the feed block portion 228 and then laminated with the skin layer component transferred from the third extrusion portion 222. Therefore, the third extrusion part 222 and the feed block portion 228 may be in communication with each other. Thereafter, the core layer in which the skin layer is laminated is transferred to the flow control unit 229, and the spread of the first component is induced. Preferably, the flow control may be a T-die or a coat-hanger die. Meanwhile, when the skin layer and the core layer are laminated at the same time, the third extrusion part 222 may communicate with the collection block part 227, and in this case, the feed block part 228 may be omitted.

18 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another exemplary embodiment of the present invention. 17, the first extrusion part 220 transfers the first component to the four first pressing means 233, 234, 235, and 236. The first pressurizing means 233, 234, 235 and 236 have different discharge amounts and discharge the first component into the plurality of slit-shaped extrusion ports 241, 242, 243 and 244. The second extruding portion 221 feeds the second component to the four second pressing means 237, 238, 239, 240. The second pressurizing means 237, 238, 239 and 240 have discharge amounts different from each other and discharge the second component to the plurality of slit-shaped extrusion ports 241, 242, 243 and 244. Four multi-layer composite streams having different average optical thicknesses are produced through four slit-type extrusion ports 241, 242, 243, and 244. The first pushing means, the second pushing means, and the plurality of slit-shaped pushing-out portions form a spin block portion (C).

19 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another exemplary embodiment of the present invention. 18, the present invention is characterized in that, in order to manufacture a multilayer reflective polarizer having four groups, eight slit-type extrusion / detaching units are used instead of four slit-type extrusion / detaching units, and multi-stage laminating is performed . Specifically, the first pressing means 233 discharges the first component to the two slit-shaped pushing-out portions 250, 251. The second pressing means 234 also discharges the first component to the two slit-shaped pushing-out portions 250, 251. The two slit-shaped extrusion ports 250 and 251 have the same average optical thickness between the multilayer composite streams since the first component and the second component are transported through the same first pressing means and second pressing means. In this way, eight multi-layer composite streams are formed and the two multi-layer composite streams have the same average optical thickness. The two multilayer composite streams having the same average optical thickness are laminated in the first leg portions 258, 259, 260, and 261 to form four multi-layer composite streams, respectively, and the four multi- ) To form one core layer.

Meanwhile, in FIG. 19, one first pressing means transfers the first component to the two slit-type extrusion molds, but it is apparent to those skilled in the art that the first component can be transferred to the two or more slit-type extrusion molds. The same may be applied to the second pressing means.

Meanwhile, Korean Patent Application No. 2011-0145132 for a method and apparatus for manufacturing a multilayer reflective polarizer is incorporated herein by reference.

Hereinafter, the present invention will be described in detail by Examples and Experimental Examples. The following Examples and Experimental Examples are merely illustrative of the present invention, and the scope of the present invention is not limited to the following Examples and Experimental Examples.

≪ Example 1 >

The process was performed as shown in FIG. 17. Specifically, PEN having a refractive index of 1.65 as a first component and dimethyl terephthalate and dimethyl-2,6-naphthalene dicarboxylate as a second component in a molar ratio of 6: 4 are mixed with ethylene glycol (EG) and 1. : Refractive index polymerized to 90% by weight of polycarbonate and polycyclohexylene dimethylene terephthalate (PCTG) as a co-PEN and skin layer component having a refractive index of 1.64 reacted at a molar ratio of 2 A polycarbonate alloy of 1.58 was charged to the first extruded portion, the second extruded portion, and the third extruded portion, respectively. The extrusion temperature of the first component and the second component was 295 캜, and Cap. The polymer flow was calibrated through adjustment and the skin layer was subjected to an extrusion process at a temperature level of 280 占 폚.

Four composites with different average optical thicknesses were prepared using the four slit extruded molds shown in FIGS. 8 and 9. Specifically, the first component transferred from the first extruder is distributed to the four slit-type extrusion drills, and the second component transferred from the second extruder is transferred to the four slit-type extrusion drills. One slit-type extrusion mold is composed of 300 layers, the thickness of the slit of the first slit-type extrusion mold at the bottom of the fifth mold distribution plate of FIG. 9 is 0.26 mm, and the slit thickness of the second slit extrusion mold is 0.21 mm. The slit thickness of the third slit extruded die was 0.17 mm, the slit thickness of the fourth slit extruded die was 0.30 mm, and the diameter of the discharge port of the sixth die distribution plate was 15 mm 15 mm. Four composite streams discharged through the four slit-type extrusion ports were transported through a separate flow path and then lapped in a collection block to form one core layer polymer. In the feed block having a three-layer structure, a skin layer component flowed through the flow path from the skin layer extrusion part to form a skin layer on the upper and lower surfaces of the core layer polymer. The core layer polymer in which the skin layer was formed was induced in the coat hanger die of FIGS. 15 and 16 to correct the flow velocity and the pressure gradient. Specifically, the width of the die inlet is 200 mm, the thickness is 20 mm, the width of the die outlet is 960 mm, the thickness is 2.4 mm, and the flow rate is 1 m / min. Then, a smoothing process was performed on the cooling and casting rolls and stretched 6 times in the MD direction. Subsequently, heat setting was performed through an IR heater at 180 ° C. for 2 minutes to prepare a multilayer reflective polarizer as shown in FIG. 7. The refractive index (nx: 1.88, ny: 1.64, nz: 1.64) of the first component of the produced reflective polarizer was 1.64 and the refractive index of the second component was 1.64. The A group had 300 layers (150 repetition units), the thickness of the repeating unit was 168 nm, the average optical thickness was 275.5 nm, and the optical thickness variation was about 20%. The B group had 300 layers (150 repetition units), the thickness of the repeating unit was 138 nm, the average optical thickness was 226.3 nm, and the optical thickness variation was about 20%. The C group had 300 layers (150 repetition units), the thickness of the repeating unit was 110 nm, the average optical thickness was 180.4 nm, and the optical thickness variation was about 20%. The D group had 300 layers (150 repetition units), the thickness of the repeating unit was 200 nm, the average optical thickness was 328 nm, and the optical thickness variation was about 20%. The core layer thickness and the skin layer thickness of the manufactured multilayer reflective polarizer were set to 92.4 탆 and 153.8 탆, respectively, so that the total thickness was 400 탆.

On the other hand, as a binder, 100 parts by weight of a urethane acrylate compound having a molecular weight of 2000 MW and 6 functional groups (Miwon Corporation, Miramer PU620), and a polybutyl methacrylate polydisperse beads (Gantz Corporation, GB-05S) 600 having an average particle diameter of 5 µm Parts by weight, 100 parts by weight of propylene glycol monomethyl ether (PGME) 11 parts by weight of photoinitiator (Ciba-Geigy, Igacure-184), 0.025 parts by weight of silicone oil, 0.1 parts by weight of light stabilizer (Ciba-Geigy, Tinuvin 5050), A bead coating solution was prepared by mixing 9 parts by weight of a quaternary ammonium salt-based polymer antistatic agent (PU101, Japan) and stirring it at 1000 rpm, followed by sand milling for 30 minutes. This was coated on one surface of the reflective polarizer with a Mayer bar and dried at 80 ° C. for 1 minute, and then irradiated with ultraviolet rays. (350mJ / cm 2, 160W / cm 2) The coating layer formed in this manner has a thickness of 5 μm and supports a bead coating layer. The binder was found to be 2.5㎛ by FE-SEM. The back coating layer was applied in the same manner as above using 40 parts by weight based on 100 parts by weight of the binder compound, and dried after UV curing to form a coating layer.

<Example 2>

The bead coating layer was formed in the same manner as in Example 1 except that 1400 parts by weight of GB-05S PBMA (Polybutylmethacrylate) polydisperse beads having an average particle diameter of 5 μm of Ganz was added as added beads.

<Example 3>

A bead coating layer was formed in the same manner as in Example 1 except that 600 parts by weight of MX-500 PMMA (Polymethylmethacrylate) monodisperse beads having an average particle diameter of SOKEN Co., Ltd. was added as the added beads.

<Example 4>

A bead coating layer was formed in the same manner as in Example 1, except that 1400 parts by weight of MX-500 PMMA (polymethylmethacrylate) monodisperse beads having an average particle diameter of SOKEN Co., Ltd. was added as the added beads.

&Lt; Comparative Example 1 &

The coating layer was formed in the same manner as in Example 1 except that no beads were added.

Comparative Example 2

100 parts by weight of bisphenol A epoxy diacrylate compound having a molecular weight of 700 MW and two functional groups was used as a binder, and 600 parts by weight of GB-05S PBMA (polybutylmethacrylate) polydisperse beads having an average particle diameter of 5 μm was added as Ganz. Except for the same as in Example 1 to form a bead coating layer.

&Lt; Comparative Example 3 &

100 parts by weight of a bisphenol A epoxy diacrylate compound having a molecular weight of 700 MW and two functional groups was used as a binder, and 600 parts by weight of MX-500 PMMA (polymethylmethacrylate) monodisperse beads having an average particle diameter of 5 μm was added as a beads. Except for the same as in Example 1 to form a bead coating layer.

&Lt; Comparative Example 4 &

100 parts by weight of a bisphenol A epoxy diacrylate compound having a molecular weight of 700 MW and two functional groups as a binder was added, and 600 parts by weight of MR-2G polymethylmethacrylate polydisperse beads having an average particle diameter of 5 μm of SOKEN was added. Except for the same as in Example 1 to form a bead coating layer.

<Experimental Example>

The following physical properties of the reflective polarizers of Examples 1 to 4 and Comparative Examples 1 to 4 were evaluated, and the results are shown in Table 1.

1. Adhesion Strength Evaluation Method

Divide the cells by crosshatching 10mm horizontally and vertically 10mm by 10mm in 1mm increments. Put 3M (# 610) tape on 100 cells and press it tightly by hand, then peel it off at right angles to the tape adhesive direction. At this time, the number of eyes remaining on the film base material is measured to evaluate the adhesion.

2. Curling method

After curing the polarizer, cut into 20cm ⅹ 20cm size and put it on the plate and measure the height of the plate and the curled film of the four sides, respectively, and calculate the average (unit: mm).

3. Pencil Hardness Measurement

The pencil hardness is 10mm, 5 times, and the surface of the coated surface is checked using a pencil hardness tester in accordance with JIS K5400.

4. Haze measurement

Haze was measured using Haze Meter (HM-150, Murakami).

5. Color coordinate measurement

Color coordinate variation was measured using an optical measuring device (Topcon, SR-3AR).

6. Antistatic function measurement

The sheet resistance (Ω / sq) is measured by a surface resistance measuring instrument (Trustat Worksurface tester, ST-3) at a temperature of 25 ° C., a humidity of 50%, and a constant humidity.

7. High temperature and high humidity test

Check the migration after leaving the thermo-hygrostat chamber at 60 ℃, 75% RH, 96HR.

Ra (μm) Haze
(%) Color coordinates Pencil hardness Adhesiveness Curl Daejeon
(Ω / sq) High temperature and high humidity
Test Exterior features Example 1 0.85 75.1 X: 0.2729
Y: 0.2833 H Prize <1 mm 10 ¹¹ No metastasis Good Example 2 0.86 88.2 X: 0.2731
Y: 0.2805 2H Prize <1 mm 10 ¹² No metastasis Good Example 3 0.73 73.2 X: 0.2734
Y: 0.2816 H Prize <1 mm 10 ¹¹ No metastasis Good Example 4 0.84 84.2 X: 0.2729
Y: 0.2814 2H Prize <1 mm 10 ¹² No metastasis Good Comparative Example 1 0.05 23.5 X: 0.2716
Y: 0.2791 HB medium <4 mm 10 ¹¹ No metastasis Good Comparative Example 2 0.86 71.9 X: 0.2731
Y: 0.2813 F medium <3 mm 10 ¹¹ No metastasis Good Comparative Example 3 0.83 74.1 X: 0.2732
Y: 0.2817 F medium <3 mm 10 ¹¹ No metastasis Good Comparative Example 4 0.18 73.5 X: 0.2742
Y: 0.2827 F medium <5 mm 10 ¹¹ No metastasis Good

It can be seen from Table 1 that the reflective polarizers of Examples 1 to 4 satisfying the bead coating composition ratio and the Ra value of the present invention have superior optical properties as compared to Comparative Examples 1 to 4 which do not satisfy this.

Since the reflective polarizer of the present invention has excellent light modulation performance, it can be widely used in fields where optical modulation is required. Specifically, it can be widely used in flat panel display technologies such as a liquid crystal display device, a projection display, a plasma display, a field emission display, and an electroluminescence display which require high brightness such as a mobile display, an LCD and an LED.

Claims (20)

In order to transmit the first polarized light irradiated from the outside and reflect the second polarized light, a first layer having in-plane birefringence and a second layer alternately laminated with the first layer, wherein the first layer and the second layer are at least The refractive index differs in one axial direction, the first layer and the second layer extend in at least one axial direction, the first layer and the second layer form one repeating unit, and the repeating units have a desired wavelength. Groups are formed to reflect the transverse wave (S wave) of the group, the groups are two or more, the groups are integrally formed, and at least one surface of the core layer and the core layer having a different average optical thickness of repeating units between groups A multilayer reflective polarizer comprising a skin layer formed integrally with and a bead coating layer formed on at least one surface of the skin layer. The method of claim 1,
And a birefringent interface is formed between the first layer and the second layer. The multilayer reflective polarizer of claim 1, wherein the repeating units form three groups to reflect light of four wavelength bands. The method of claim 1,
The optical thickness of the repeating units included in the same group is a multilayer reflective polarizer, characterized in that the thickness deviation within 20% of the average optical thickness. 4. The multilayer reflective polarizer of claim 3, wherein the four reflection bands include wavelength bands of 350 nm, 450 nm, 550 nm, and 650 nm. 2. The multilayer reflective polarizer of claim 1, wherein the plurality of groups differ by at least 5% in average optical thickness of repeating units. The multilayer reflective polarizer of claim 1, wherein at least 25 repeating units are included in one group. The multilayer reflective polarizer of claim 1, wherein the number of repeating units included in one group is 100 or more. The multi-layered reflection of claim 1, wherein the refractive index of the first layer and the second layer has a difference in refractive index between two axial directions of 0.05 or less and a difference in refractive index for the other one axial direction of 0.1 or more. Type polarizer. The method of claim 1,
And said first layer has optical birefringence and said second layer is optically isotropic. The method of claim 1,
Multi-layer reflective polarizer, characterized in that the adhesive layer is not formed between the group and the group. The method of claim 1,
The multilayer reflective polarizer, characterized in that no adhesive layer is formed between the core layer and the skin layer. The method of claim 1,
And the skin layer is stretched. The method of claim 1,
The bead coating layer is beads based on 100 parts by weight of the binder A multilayer reflective polarizer comprising a bead coating layer, characterized in that 30 to 1700 parts by weight are mixed. 15. The method of claim 14,
Multi-layer reflective polarizer comprising a bead coating layer, characterized in that the average particle diameter of the bead is 1 ~ 30㎛. The method of claim 1,
The bead is a multilayer reflective polarizer comprising a bead coating layer, characterized in that any one or more selected from the group consisting of silica, zirconia, titanium dioxide, styrene, propylene, ethylene, urethane and methyl (meth) acrylate. 15. The method of claim 14,
The binder is a multilayer reflective polarizer comprising a bead coating layer, characterized in that any one or more selected from the group consisting of aliphatic urethane acrylate, epoxy acrylate, melamine acrylate and polyester acrylate. 15. The method of claim 14,
The thickness of the binder is a multilayer reflective polarizer comprising a bead coating layer, characterized in that 0.5 to 50㎛. The method of claim 1,
Arithmetic mean roughness (Ra) of the bead coating layer is a multilayer reflective polarizer comprising a bead coating layer, characterized in that 0.1 ~ 5㎛. The method of claim 1,
The bead is a multi-layer reflective polarizer comprising a bead coating layer, characterized in that the mixed monodisperse beads and polydisperse beads.

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