阅读说明：本技术 硬涂膜 (Hard coating film ) 是由 边真锡 金在永 张影来 申伦扜 徐光锡 于 2018-09-14 设计创作，主要内容包括：提供了硬涂膜,其包含：聚合物粘合剂树脂；分散在聚合物粘合剂树脂中并且平均颗粒尺寸为5nm至70nm的第一无机颗粒；和分散在聚合物粘合剂树脂中并且平均颗粒尺寸为70nm至150nm的第二无机颗粒,其中平均颗粒尺寸为70nm至150nm的第二无机颗粒的含量为4重量％至12重量％,以及在利用TAC膜通过向硬涂膜的表面施加400g的负荷而测量的测量摩擦力的图中,基于平均摩擦力的最大振幅(A)为0.15或更小。(Provided is a hard coat film comprising: a polymeric binder resin; first inorganic particles dispersed in the polymer binder resin and having an average particle size of 5nm to 70 nm; and second inorganic particles dispersed in the polymer binder resin and having an average particle size of 70nm to 150nm, wherein a content of the second inorganic particles having an average particle size of 70nm to 150nm is 4 wt% to 12 wt%, and a maximum amplitude (a) based on the average friction force is 0.15 or less in a graph of measuring the friction force measured by applying a load of 400g to a surface of the hard coating film using a TAC film.)

1. A hardcoat film comprising: a polymeric binder resin; first inorganic particles dispersed in the polymer binder resin and having an average particle size of 5nm to 70 nm; and second inorganic particles dispersed in the polymer binder resin and having an average particle size of 70nm to 150nm, wherein a content of the second inorganic particles having an average particle size of 70nm to 150nm is 4% by weight to 12% by weight, and a maximum amplitude (a) based on an average friction force is 0.15 or less in a graph for measuring a friction force measured by applying a load of 400g to a surface of the hard coat film using a TAC (triacetyl cellulose) film.

2. The hardcoat of claim 1 wherein two or more of the second inorganic particles are distributed on the polymeric binder resin while being spaced apart by a distance of 0.1 μ ι η or more.

3. The hard coating film according to claim 1, wherein there is no agglomeration between the second inorganic particles having an average particle size of 70nm to 150 nm.

4. The hard coat film according to claim 1, wherein, for at least two of the second inorganic particles, a distance between one surface of the hard coat film and a center of the second inorganic particle in a direction perpendicular to the one surface of the hard coat film is 35nm to 5.0 μm.

5. The hard coat film according to claim 4, wherein at least two of the second inorganic particles having a distance of 35nm to 5.0 μm between one surface of the hard coat film and the center of the particle in a direction perpendicular to the one surface of the hard coat film are adjacent to each other while being spaced apart by a distance of 0.1 μm to 1.5 μm in a horizontal direction with respect to the one surface of the hard coat film.

6. The hard coat film according to claim 1, wherein each of the second inorganic particles is located only inside the hard coat film.

7. The hard coating film according to claim 1, wherein reactive functional groups are respectively introduced on surfaces of the first inorganic particles and the second inorganic particles.

8. The hard coating film according to claim 7, wherein the first inorganic particles and the second inorganic particles have one or more reactive functional groups selected from a (meth) acrylate group, an epoxy group, a vinyl group, and a thiol group, or a compound containing the reactive functional groups, respectively, introduced thereon.

9. The hardcoat of claim 8 wherein the compound comprising the reactive functional group is a silane compound or a hydroxide compound comprising one or more reactive functional groups selected from a (meth) acrylate group, an epoxy group, a vinyl group, and a thiol group.

10. The hard coating film according to claim 7, wherein the reactive functional group introduced onto each surface of the first inorganic particle and the second inorganic particle forms a cross-linking bond with the polymer binder resin.

11. The hardcoat of claim 1 wherein the polymeric binder resin comprises one or more selected from the group consisting of acrylic resins, epoxy groups, vinyl groups, and thiol groups.

12. The hard coating film according to claim 1, further comprising a fluorine-based compound containing a reactive functional group, the fluorine-based compound forming a crosslinking bond with the polymer binder resin.

13. The hard coating film according to claim 1, wherein the content of the first inorganic particles is 1 to 30% by weight with respect to 100% by weight of the hard coating film.

14. The hard coating film according to claim 1, wherein the first inorganic particles and the second inorganic particles are one or more selected from silica and metal oxides.

15. The hard coating film according to claim 1, wherein at least one surface of the hard coating film has two or more irregularities, and the height of the irregularities is from 1nm to 50 nm.

16. The hard coating film according to claim 15, wherein an average distance between the concavities and convexities is 0.1 μm to 1.5 μm.

17. The hard coating film according to claim 1, wherein the hard coating film has a thickness of 500nm to 30 μm.

18. The hardcoat film of claim 1 wherein the maximum amplitude (a) is the maximum value of absolute values of a difference between the average frictional force and the maximum frictional force and a difference between the average frictional force and the minimum frictional force after measuring the average frictional force, the maximum frictional force, and the minimum frictional force in a dynamic test distance interval of the frictional force measurement map.

Technical Field

Cross Reference to Related Applications

This application claims the benefit of korean patent application No. 10-2017-0118861, filed by 2017, 9, 15 to the korean intellectual property office, the disclosure of which is incorporated herein by reference in its entirety.

The present invention relates to a hard coat film for the purpose of protecting the surface of a display or the like.

Background

An image display surface in an image display device such as a liquid crystal display, a CRT display, a projection display, a plasma display, an electroluminescence display, or the like is required to have scratch resistance in order to prevent the appearance of scratches during handling. Improvement in scratch resistance of an image display surface in an image display device is generally achieved by forming a hard coat film on a base film or by using a hard coat film (optical laminate) additionally having an optical function (e.g., antireflection property, glare resistance property, etc.).

During the winding process of the hard coating films using the roll, the distance between the hard coating films becomes small, and in an extreme case, a blocking phenomenon in which the hard coating films adhere to each other occurs. When the hard coating films adhered to each other are fed to travel on the wire, the film is scratched when the film is peeled from the winding roll, or the film is scratched due to vibration while traveling on the wire or while being in contact with the guide roll. This may cause a significant drop in yield.

Previously, several methods have been proposed to prevent the hard coating film from being scratched by applying an anti-blocking function to the surface of the hard coating film. For example, in order to prevent blocking, a technique of forming irregularities (unevenness) on the surface of a hard coat film by phase separation of an oligomer and a monomer has been proposed. There is also proposed a technique of forming irregularities by adding particles to a hard coating film to secure anti-blocking properties. However, with these known methods of forming the irregularities, it is difficult to control uniform formation of the irregularities. Therefore, coarse irregularities may be provided to cause defects in appearance, or when the formation of irregularities is insufficient, the anti-blocking property may be insufficient.

Disclosure of Invention

Technical problem

The present invention provides a hard coating film having excellent optical characteristics and an anti-blocking function while maintaining excellent physical characteristics.

Technical scheme

According to an embodiment of the present invention, there is provided a hard coating film comprising: a polymeric binder resin; first inorganic particles dispersed in the polymer binder resin and having an average particle size of 5nm to 70 nm; and second inorganic particles dispersed in the polymer binder resin and having an average particle size of 70nm to 150nm, wherein a content of the second inorganic particles having an average particle size of 70nm to 150nm is 4% by weight to 12% by weight, and a maximum amplitude (a) based on an average friction force is 0.15 or less in a graph for measuring a friction force measured by applying a load of 400g to a surface of the hard coating film using a TAC (triacetyl cellulose) film.

Hereinafter, the hard coating film according to an embodiment of the present invention will be described in more detail.

In the present invention, the terms "first", "second", and the like are used to describe various components, and these terms are used only to distinguish one component from other components.

Furthermore, (meth) acrylates cover both acrylates and methacrylates.

Further, the fluorine-based compound means a compound containing at least one fluorine atom in the compound.

According to an embodiment of the present invention, there is provided a hard coating film comprising: a polymeric binder resin; first inorganic particles dispersed in the polymer binder resin and having an average particle size of 5nm to 70 nm; and second inorganic particles dispersed in the polymer binder resin and having an average particle size of 70nm to 150nm, wherein a content of the second inorganic particles having an average particle size of 70nm to 150nm is 4% by weight to 12% by weight, and a maximum amplitude (a) based on the average friction force is 0.15 or less in a graph for measuring the friction force measured by applying a load of 400g to a surface using a TAC (triacetyl cellulose) film.

Conventionally, a method of forming irregularities on the surface of a hard coat film in order to prevent blocking of the hard coat film has been known, but there is a problem that it is difficult to control the formation of uniform irregularities.

Accordingly, the present inventors have conducted studies on a hard coating film, and found that when two kinds of inorganic particles having different average particle sizes are dispersed in a polymer binder resin and the content of second inorganic particles having an average particle size of 70nm to 150nm in the two kinds of inorganic particles is controlled to 4 wt% to 12 wt%, and the maximum amplitude (a) based on the average frictional force in a graph for measuring frictional force measured by applying a load of 400g to the surface of the hard coating film using a TAC film is 0.15 or less, the second inorganic particles dispersed in the hard coating film do not agglomerate, and thus uniform irregularities are formed to exhibit an anti-blocking function, and the hard coating film has excellent physical and optical characteristics, thereby completing the present invention.

In particular, the hard coating film of this embodiment may include a predetermined amount of the second inorganic particles, and the first inorganic particles, and thus it may have inherently uniform surface characteristics while having a low haze value and high light transmittance, thereby achieving an anti-blocking function.

More specifically, in the graph for measuring the frictional force measured by applying a load of 400g to the surface of the hard coat film using the TAC film, the maximum amplitude (a) of the hard coat film based on the average frictional force is 0.15 or less, 0.001 to 0.13, 0.005 to 0.10, 0.008 to 0.08, or 0.01 to 0.05. When the maximum amplitude (a) of the hard coating film based on the average frictional force is 0.15 or less, the second inorganic particles distributed inside the hard coating film are not agglomerated, and particularly, the second inorganic particles located near the surface of the hard coating film are uniformly distributed without being agglomerated, thereby forming uniform irregularities, and thus, the hard coating film exhibits an excellent anti-blocking function.

In contrast, when the maximum amplitude (a) is greater than 0.15, the second inorganic particles are agglomerated to form uneven unevenness and thus generate haze, resulting in deterioration of optical characteristics and occurrence of blocking phenomenon during a winding process of a hard coating film using a roll.

The friction force measurement chart of the hard coat film can be obtained by: a TAC film was brought into contact with the surface of the hard coat film, a slider (slid) having a load of 400g was placed thereon, and then the frictional force was measured while moving the slider at a constant test speed for a specific distance. In this regard, the friction force measurement map is obtained as a friction force (y-axis) with respect to a test distance (x-axis), and the test distance is divided into a static test distance interval and a dynamic test distance interval.

In this connection, the static test distance is an interval for measuring the static friction force, which is defined as the friction force measured at a distance of 3cm from the start of measurement. Further, the dynamic test distance is an interval for measuring the kinetic friction force, and is determined as an average value of the friction force measured in the interval in which the slide member moves (specifically, the friction force measured in the dynamic test distance interval).

In the present invention, the maximum amplitude (a) measured in the dynamic test distance section of the test distance sections means the maximum value among absolute values of differences between the average friction force and the maximum friction force or the minimum friction force after the average friction force, the maximum friction force, and the minimum friction force are measured in the dynamic test distance section.

Therefore, since the parameter of the maximum amplitude (a) is not measured from the starting point of the test distance, but is measured for the difference between the average frictional force and the maximum frictional force or the minimum frictional force in the dynamic test distance, it can be used as a measure for determining the smoothness of the surface of the hard coating film.

The content of the second inorganic particles is 4 to 12 wt%, 5 to 11 wt%, or 6 to 9 wt% with respect to 100 wt% of the hard coating film. When the hard coating film contains the second inorganic particles in the above amount, the second inorganic particles distributed inside the hard coating film are not agglomerated, and in particular, the second inorganic particles located near the surface of the hard coating film are uniformly distributed without being agglomerated, thereby forming uniform irregularities.

On the polymer binder resin contained in the hard coat film, two or more second inorganic particles are distributed, and a distance between the two or more second inorganic particles distributed on the polymer binder resin is 0.1 μm or more, 0.1 μm to 1.5 μm, 0.2 μm to 1.2 μm, or 0.5 μm to 1.0 μm. The distance between the second inorganic particles distributed on the polymer binder resin is based on the distance from the center of one second inorganic particle to the center of another second inorganic particle closest thereto. Therefore, since the distance between the two second inorganic particles (i.e., the shortest distance among the distances between the surfaces of the two second inorganic particles) is 0.1 μm or more, the second inorganic particles do not contact each other, and furthermore, agglomeration between the second inorganic particles does not occur.

For the at least two second inorganic particles included in the hard coating film, a distance between one surface of the hard coating film and a center of the second inorganic particle in a direction perpendicular to the one surface of the hard coating film may be 35nm to 5.0 μm. In this connection, the center of the second inorganic particle means the midpoint of the particle diameter of the second inorganic particle.

As described above, since the particle diameter of the second inorganic particles is 70nm to 150nm, the lower limit of the radius of the second inorganic particles may be 35 nm. Therefore, since the distance between one surface of the hard coat film and the center of the second inorganic particle is controlled to be 35nm or more, at least two second inorganic particles may be located near the surface of the hard coat film.

Further, since the distance between one surface of the hard coat film and the center of the second inorganic particle is controlled to be 35nm or more, each second inorganic particle may be located only inside the hard coat film, which means that all the individual second inorganic particles are distributed inside the hard coat film, more specifically, means that even a part of the second inorganic particles is not exposed to the outside of the hard coat film.

Meanwhile, if the second inorganic particles contact the surface of the hard coating film, for example, if the distance from one surface of the hard coating film to the center of the second inorganic particles is equal to the radius of the second inorganic particles, it can be considered that the second inorganic particles are not substantially exposed to the outside of the hard coating film.

At least two second inorganic particles in which a distance between one surface of the hard coat film and the center of the particle in a direction perpendicular to the one surface of the hard coat film is 35nm to 5.0 μm may elevate the binder resin to form irregularities on the one surface of the hard coat film. Further, as described above, since the second inorganic particles do not agglomerate, coarsening of the size of the irregularities formed by the second inorganic particles does not occur, and the size and distribution of the irregularities are controlled.

At least two second inorganic particles in which a distance between one surface of the hard coat film and a center of the particle in a direction perpendicular to the one surface of the hard coat film is 35nm to 5.0 μm may be adjacent to each other in a horizontal direction with respect to the one surface of the hard coat film while being spaced apart by a distance of 0.1 μm to 1.5 μm. The distance of the second inorganic particles adjacent to each other in the horizontal direction with respect to one surface of the hard coating film means an average value of the distances between the centers of one second inorganic particle and another adjacent second inorganic particle. In particular, since the average particle size of the second inorganic particles is 70nm to 150nm and the average distance between the centers of the second inorganic particles adjacent to each other in the horizontal direction with respect to one surface of the hard coating film is at least 100nm or more, the second inorganic particles may not contact each other and, in addition, agglomeration between the second inorganic particles may not occur.

If the average distance between the second inorganic particles is less than 100nm, the haze of the hard coating film increases, thereby causing a problem in that the surface thereof looks hazy. If the average distance is more than 1.5 μm, the anti-blocking property of the hard coating film may be deteriorated.

Fig. 1 is a cross-sectional TEM (transmission electron microscope) image of a hard coating film according to an embodiment of the present invention at 2500 times magnification. According to the image, two or more second inorganic particles are located near the surface of the hard coating film. Further, an arrow in fig. 1 indicates a method of measuring a distance between the second inorganic particles adjacent to each other in a horizontal direction with respect to one surface of the hard coating film. The shortest distance between the second inorganic particles adjacent to each other measured by this method may be 450nm to 1.7 μm, 480nm to 1.6 μm, or 500nm to 1.5 μm, and the average value of the shortest distances as described above is 500nm to 1.5 μm.

The height of the irregularities formed on the hard coating film may be 1nm to 50nm, 5nm to 45nm, 10nm to 40nm, or 15nm to 30 nm. If the height of the irregularities is less than 1nm, sufficient irregularities are not formed on the surface of the hard coating film, and the hard coating film may not exhibit the anti-blocking function. If the height of the unevenness is more than 50nm, there is a problem that haze is generated.

Meanwhile, the average distance between the irregularities formed on the hard coating film may be 0.1 to 1.5 μm, 0.2 to 1.2 μm, or 0.5 to 1.0 μm. The average distance between the concavities and convexities means an average value of distances from the center of one concave and convex portion to the center of another adjacent concave and convex portion. If the average distance between the irregularities is less than 0.1 μm, haze is generated, whereas if the average distance between the irregularities is greater than 1.5 μm, the interval between the irregularities on the surface of the hard coating film is too large, and thus the anti-blocking function may not be obtained.

The hard coat film contains two kinds of first inorganic particles having different average particle sizes. First, the first inorganic particles have an average particle size of 5nm to 70nm, 10nm to 40nm, or 15nm to 30 nm. If the average particle size of the first inorganic particles is less than 5nm, the hardness of the hard coating film may be weakened.

Meanwhile, the second inorganic particles have an average particle size of 70nm to 150nm, 75nm to 140nm, or 80nm to 135 nm. If the average particle size of the second inorganic particles is less than 70nm, irregularities having a sufficient size may not be formed, and thus anti-blocking properties may not be obtained.

The first inorganic particles and the second inorganic particles may be one or more selected from silica and metal oxides, and the metal oxide means a metal oxide other than silica as a metalloid oxide.

The content of the first inorganic particles may be 1 to 30% by weight with respect to 100% by weight of the hard coating film.

Meanwhile, a reactive functional group or a compound including a reactive functional group may be introduced on the surface of the first inorganic particle and the second inorganic particle, respectively. The reactive functional group may include various functional groups known to participate in polymerization by a stimulus such as light, heat, or the like. Specific examples of the reactive functional group may include a (meth) acrylate group, an epoxy group, a vinyl group, and a thiol group.

Further, the surfaces of the first inorganic particles and the second inorganic particles may be respectively introduced with a compound including a reactive functional group, and examples of the compound including a reactive functional group may include a silane compound and a hydroxide compound including a reactive functional group.

For example, the silane compound containing a reactive functional group may include vinylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-vinyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, p-vinyltrimethoxysilane, 3-, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1, 3-dimethylbutylidene) propylamine, n-phenyl-3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, and the like. These compounds may be used alone or as a mixture of two or more thereof.

Since the reactive functional group or the compound containing the reactive functional group is introduced on the surface of the first inorganic particle and the second inorganic particle, respectively, the reactive functional group may form a cross-linking bond with the polymer binder resin during the formation of the hard coating film, and the particles are sufficiently dispersed in the binder resin. Conversely, if the particles do not have reactive functional groups, the particles agglomerate with each other. Therefore, the finally manufactured hard coating film may have improved mechanical properties and anti-blocking properties without generating haze.

The hard coating film may include a polymer binder resin containing one or more selected from among an acrylic resin, an epoxy group, a vinyl group, and a thiol group.

The hard coating film may further include a fluorine-based compound having a reactive functional group, and the fluorine-based compound having a reactive functional group may form a crosslinking bond with the polymer binder resin. The reactive functional group contained in the fluorine-based compound may be the same as or different from the reactive group introduced into the first inorganic particle and the second inorganic particle. For example, the reactive functional group contained in the fluorine-based compound may be a (meth) acrylate group, an epoxy group, a vinyl group, or a thiol group; or may be a silane compound or a hydroxide compound containing a (meth) acrylate group, an epoxy group, a vinyl group or a thiol group.

At least two second inorganic particles in which the distance between one surface of the hard coat film and the center of the particle in the direction perpendicular to the one surface of the hard coat film is 35nm to 5.0 μm may elevate the binder resin to form irregularities on the one surface of the hard coat film. In particular, since the second inorganic particles do not agglomerate, a hard coating film having irregularities uniformly formed on the surface thereof can be obtained.

The thickness of the hard coating film may be 500nm to 30 μm, 1 μm to 25 μm, 5 μm to 20 μm, or 8 μm to 15 μm. If the thickness of the hard coating film is less than 500nm, the hardness of the hard coating film may be deteriorated, and if the thickness is more than 30 μm, the hard coating film may be severely curled, resulting in poor workability.

Hereinafter, a method of manufacturing a hard coating film will be described, but the method of manufacturing a hard coating film is not limited thereto.

First, a transparent base film and a composition for a hard coat film are prepared. The composition may comprise: a photocurable and/or thermally curable monomer or oligomer; first inorganic particles having an average particle size of 5nm to 70nm and having a reactive functional group introduced on the surface thereof; and second inorganic particles having an average particle size of 70nm to 150nm and having a reactive functional group introduced on the surface thereof.

Next, the composition for a hard coating film is coated on a transparent base film, and then dried. The coating method is not particularly limited as long as it is used to uniformly coat the film. Various methods such as spin coating, dipping, spray coating, die coating, bar coating, roll coating, meniscus coating (method), flexographic printing, screen printing, and feed coater (method) may be used. The drying method may be exemplified by vacuum drying or thermal drying or a combination thereof. For example, when a ketone-based solvent is used as the solvent, the drying process may be generally performed at a temperature of room temperature to 80 ℃, or 40 ℃ to 60 ℃ for 20 seconds to 3 minutes, or 30 seconds to 1 minute.

In this regard, the first inorganic particles and the second inorganic particles uniformly dispersed in the composition for a hard coating film are uniformly dispersed inside the hard coating film during the drying process, particularly, there is no agglomeration between the second inorganic particles in which the distance between one surface of the hard coating film and the center of the particles in the direction perpendicular to the one surface of the hard coating film is 35nm to 5.0 μm.

Thereafter, the dried coating film after coating with the composition may be cured by light irradiation and/or heating. As a result, the photocurable and/or thermally curable monomer or oligomer is polymerized, and the first inorganic particles and the second inorganic particles may form crosslinks with the photocurable and/or thermally curable monomer or oligomer, thereby forming a hard coating film. Therefore, the second inorganic particles in which the distance between one surface of the hard coat film and the center of the particle is 35nm to 5.0 μm can elevate the binder resin to form irregularities on one surface of the hard coat film. In particular, since the second inorganic particles do not agglomerate, a hard coating film having irregularities uniformly formed on the surface thereof can be obtained.

In the light irradiation, ultraviolet light, visible light, electron beam, ionizing radiation, or the like may be mainly used. In the case of ultraviolet curing, ultraviolet rays emitted from a light source such as an ultra-high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a xenon arc lamp, a metal halide lamp, or the like may be used. For cumulative exposure at an ultraviolet wavelength of 365nm, the irradiation dose of the light source is 50mJ/cm²To 5000mJ/cm². The heating may be generally carried out at a temperature of 40 ℃ to 120 ℃. Alternatively, the reaction may be allowed to proceed by leaving the membrane at room temperature for 24 hours or more.

Advantageous effects

According to the present invention, there is provided a hard coating film: which has excellent optical characteristics due to low haze and has an excellent anti-blocking function while maintaining excellent physical characteristics such as scratch resistance, pencil hardness, and the like.

Drawings

Fig. 1 is a sectional transmission electron microscope image of a hard coating film according to an embodiment of the present invention.

Detailed Description

The present invention will be described in more detail in the following examples. However, the following examples are for illustrative purposes only, and the contents of the present invention are not intended to be limited thereto.

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